LD(1)

📦 version 2.47, in arch rolling

💅 LD(1) — GNU Development Tools — `ld`, the GNU linker, bestie ✨

okay so real talk: ld is the GNU linker, and it’s basically the final boss of your compile pipeline. It combines a bunch of object and archive files, relocates their data, and ties up symbol references. Usually the last step in compiling a program is running ld.

ld accepts Linker Command Language files written in a superset of AT&T’s Link Editor Command Language syntax, so you get explicit and total control over the linking process. slay.

This man page does not describe the command language; see the ld entry in info for full details on the command language and on other aspects of the GNU linker.

This version of ld uses the general purpose BFD libraries to operate on object files. That lets ld read, combine, and write object files in many different formats — for example, COFF or a.out. Different formats may be linked together to produce any available kind of object file. iconic behavior.

Aside from its flexibility, the GNU linker is more helpful than other linkers in providing diagnostic information. Many linkers abandon execution immediately upon encountering an error; whenever possible, ld continues executing, allowing you to identify other errors (or, in some cases, to get an output file in spite of the error). bestie linker is trying.

The GNU linker ld is meant to cover a broad range of situations, and to be as compatible as possible with other linkers. As a result, you have many choices to control its behavior.

✨ SYNOPSIS ✨

ld [options] objfile ...

🦋 DESCRIPTION 🦋

The linker supports a plethora of command-line options, but in actual practice few of them are used in any particular context. For instance, a frequent use of ld is to link standard Unix object files on a standard, supported Unix system. On such a system, to link a file hello.o:

ld -o <output> /lib/crt0.o hello.o -lc

This tells ld to produce a file called output as the result of linking the file /lib/crt0.o with hello.o and the library libc.a, which will come from the standard search directories. (See the discussion of the -l option below.)

Some of the command-line options to ld may be specified at any point in the command line. However, options which refer to files, such as -l or -T, cause the file to be read at the point at which the option appears in the command line, relative to the object files and other file options. Repeating non-file options with a different argument will either have no further effect, or override prior occurrences (those further to the left on the command line) of that option. Options which may be meaningfully specified more than once are noted in the descriptions below.

Non-option arguments are object files or archives which are to be linked together. They may follow, precede, or be mixed in with command-line options, except that an object file argument may not be placed between an option and its argument.

Usually the linker is invoked with at least one object file, but you can specify other forms of binary input files using -l, -R, and the script command language. If no binary input files at all are specified, the linker does not produce any output, and issues the message No input files.

If the linker cannot recognize the format of an object file, it will assume that it is a linker script. A script specified in this way augments the main linker script used for the link (either the default linker script or the one specified by using -T). This feature permits the linker to link against a file which appears to be an object or an archive, but actually merely defines some symbol values, or uses INPUT or GROUP to load other objects. Specifying a script in this way merely augments the main linker script, with the extra commands placed after the main script; use the -T option to replace the default linker script entirely, but note the effect of the INSERT command.

For options whose names are a single letter, option arguments must either follow the option letter without intervening whitespace, or be given as separate arguments immediately following the option that requires them.

For options whose names are multiple letters, either one dash or two can precede the option name; for example, -trace-symbol and --trace-symbol are equivalent. Note — there is one exception to this rule. Multiple letter options that start with a lower case 'o' can only be preceded by two dashes. This is to reduce confusion with the -o option. So for example -omagic sets the output file name to magic whereas --omagic sets the NMAGIC flag on the output.

Arguments to multiple-letter options must either be separated from the option name by an equals sign, or be given as separate arguments immediately following the option that requires them. For example, --trace-symbol foo and --trace-symbol=foo are equivalent. Unique abbreviations of the names of multiple-letter options are accepted.

Note — if the linker is being invoked indirectly, via a compiler driver (e.g. gcc) then all the linker command-line options should be prefixed by -Wl, (or whatever is appropriate for the particular compiler driver) like this:

gcc -Wl,--start-group foo.o bar.o -Wl,--end-group

This is important, because otherwise the compiler driver program may silently drop the linker options, resulting in a bad link. Confusion may also arise when passing options that require values through a driver, as the use of a space between option and argument acts as a separator, and causes the driver to pass only the option to the linker and the argument to the compiler. In this case, it is simplest to use the joined forms of both single- and multiple-letter options, such as:

gcc foo.o bar.o -Wl,-eENTRY -Wl,-Map=a.map

💅 OPTIONS 💅

Here is a table of the generic command-line switches accepted by the GNU linker:

@file — Read command-line options from file. The options read are inserted in place of the original @file option. If file does not exist, or cannot be read, then the option will be treated literally, and not removed.

Options in file are separated by whitespace. A whitespace character may be included in an option by surrounding the entire option in either single or double quotes. Any character (including a backslash) may be included by prefixing the character to be included with a backslash. The file may itself contain additional @file options; any such options will be processed recursively.

-a keyword — This option is supported for HP/UX compatibility. The keyword argument must be one of the strings archive, shared, or default. -aarchive is functionally equivalent to -Bstatic, and the other two keywords are functionally equivalent to -Bdynamic. This option may be used any number of times.
--audit AUDITLIB — Adds AUDITLIB to the DT_AUDIT entry of the dynamic section. AUDITLIB is not checked for existence, nor will it use the DT_SONAME specified in the library. If specified multiple times DT_AUDIT will contain a colon separated list of audit interfaces to use. If the linker finds an object with an audit entry while searching for shared libraries, it will add a corresponding DT_DEPAUDIT entry in the output file. This option is only meaningful on ELF platforms supporting the rtld-audit interface.
-b input-format, --format=input-format — ld may be configured to support more than one kind of object file. If your ld is configured this way, you can use the -b option to specify the binary format for input object files that follow this option on the command line. Even when ld is configured to support alternative object formats, you don’t usually need to specify this, as ld should be configured to expect as a default input format the most usual format on each machine. input-format is a text string, the name of a particular format supported by the BFD libraries. (You can list the available binary formats with objdump -i.)

You may want to use this option if you are linking files with an unusual binary format. You can also use -b to switch formats explicitly (when linking object files of different formats), by including -b input-format before each group of object files in a particular format.

The default format is taken from the environment variable GNUTARGET.

You can also define the input format from a script, using the command TARGET;

-c MRI-commandfile, --mri-script=MRI-commandfile — For compatibility with linkers produced by MRI, ld accepts script files written in an alternate, restricted command language, described in the MRI Compatible Script Files section of GNU ld documentation. Introduce MRI script files with the option -c; use the -T option to run linker scripts written in the general-purpose ld scripting language. If MRI-cmdfile does not exist, ld looks for it in the directories specified by any -L options.
-d, -dc, -dp — These three options are equivalent; multiple forms are supported for compatibility with other linkers. They assign space to common symbols even if a relocatable output file is specified (with -r). The script command FORCE_COMMON_ALLOCATION has the same effect.
--depaudit AUDITLIB, -P AUDITLIB — Adds AUDITLIB to the DT_DEPAUDIT entry of the dynamic section. AUDITLIB is not checked for existence, nor will it use the DT_SONAME specified in the library. If specified multiple times DT_DEPAUDIT will contain a colon separated list of audit interfaces to use. This option is only meaningful on ELF platforms supporting the rtld-audit interface. The -P option is provided for Solaris compatibility.
--enable-linker-version — Enables the LINKER_VERSION linker script directive, described in Output Section Data. If this directive is used in a linker script and this option has been enabled then a string containing the linker version will be inserted at the current point.

Note — this location of this option on the linker command line is significant. It will only affect linker scripts that come after it on the command line, or which are built into the linker.

--disable-linker-version — Disables the LINKER_VERSION linker script directive, so that it does not insert a version string. This is the default.
--enable-non-contiguous-regions — okay bestie, this one is lowkey a lifesaver: it avoids generating an error if an input section does not fit a matching output section. The linker tries to allocate the input section to subsequent matching output sections, and only throws an error if no output section is large enough. It’s giving “I have several non-contiguous memory regions and this input section doesn’t require one particular region” energy. The order in which input sections are evaluated does not change, fr fr, for instance:

MEMORY {
  MEM1 (rwx) : ORIGIN = 0x1000, LENGTH = 0x14
  MEM2 (rwx) : ORIGIN = 0x1000, LENGTH = 0x40
  MEM3 (rwx) : ORIGIN = 0x2000, LENGTH = 0x40
}
SECTIONS {
  mem1 : { *(.data.*); } > MEM1
  mem2 : { *(.data.*); } > MEM2
  mem3 : { *(.data.*); } > MEM3
}

with input sections:

.data.1: size 8
.data.2: size 0x10
.data.3: size 4

results in .data.1 affected to mem1, and .data.2 and .data.3 affected to mem2, even though .data.3 would fit in mem3.

This option is incompatible with INSERT statements because it changes the way input sections are mapped to output sections. 💅

--enable-non-contiguous-regions-warnings — this one enables warnings when --enable-non-contiguous-regions allows possibly unexpected matches in sections mapping, potentially leading to silently discarding a section instead of failing because it does not fit any output region. Basically a little “hey bestie, check this” alarm 🚨.
-e entry, --entry=entry — use entry as the explicit symbol for beginning execution of your program, rather than the default entry point. If there is no symbol named entry, the linker will try to parse entry as a number, and use that as the entry address (the number will be interpreted in base 10; you may use a leading 0x for base 16, or a leading 0 for base 8). For i386 PE, entry can also be the original function name (without the leading underscore and/or the trailing stdcall @number when applicable). 👑
--exclude-libs lib,lib,... — specifies a list of archive libraries from which symbols should not be automatically exported. The library names may be delimited by commas or colons. Specifying --exclude-libs ALL excludes symbols in all archive libraries from automatic export. This option is available only for ELF and PE targeted ports of the linker. For PE targets, symbols explicitly listed in a .def file are still exported, regardless of this option. For ELF targeted ports, symbols affected by this option will be treated as hidden. 🙈
--exclude-modules-for-implib module,module,... — specifies a list of object files or archive members from which symbols should not be automatically exported, but which should be copied wholesale into the import library being generated during the link. The module names may be delimited by commas or colons, and must match exactly the filenames used by ld to open the files; for archive members, this is simply the member name, but for object files the name listed must include and match precisely any path used to specify the input file on the linker’s command-line. Symbols explicitly listed in a .def file are still exported, regardless of this option. [This option is specific to PE targeted ports of the linker] 🫶
-E, --export-dynamic, --no-export-dynamic — when creating a dynamically linked executable, using the -E option or the --export-dynamic option causes the linker to add all symbols to the dynamic symbol table. The dynamic symbol table is the set of symbols which are visible from dynamic objects at run time. ✨

If you do not use either of these options (or use the --no-export-dynamic option to restore the default behavior), the dynamic symbol table will normally contain only those symbols which are referenced by some dynamic object mentioned in the link.

If you use "dlopen" to load a dynamic object which needs to refer back to the symbols defined by the program, rather than some other dynamic object, then you will probably need to use this option when linking the program itself.

You can also use the dynamic list to control what symbols should be added to the dynamic symbol table if the output format supports it. See the description of --dynamic-list.

Note that this option is specific to ELF targeted ports. PE targets support a similar function to export all symbols from a DLL or EXE; see the description of --export-all-symbols below. 💀

--export-dynamic-symbol=glob — when creating a dynamically linked executable, symbols matching glob will be added to the dynamic symbol table. When creating a shared library, references to symbols matching glob will not be bound to the definitions within the shared library. This option is a no-op when creating a shared library and -Bsymbolic or --dynamic-list are not specified. This option is only meaningful on ELF platforms which support shared libraries. 🦋
--export-dynamic-symbol-list=file — specify a --export-dynamic-symbol for each pattern in the file. The format of the file is the same as the version node without scope and node name. See VERSION for more information. 🎀
-EB — link big-endian objects. This affects the default output format. 🌈
-EL — link little-endian objects. This affects the default output format. 🌸
-f name, --auxiliary=name — when creating an ELF shared object, set the internal DT_AUXILIARY field to the specified name. This tells the dynamic linker that the symbol table of the shared object should be used as an auxiliary filter on the symbol table of the shared object name. 👑

If you later link a program against this filter object, then, when you run the program, the dynamic linker will see the DT_AUXILIARY field. If the dynamic linker resolves any symbols from the filter object, it will first check whether there is a definition in the shared object name. If there is one, it will be used instead of the definition in the filter object. The shared object name need not exist. Thus the shared object name may be used to provide an alternative implementation of certain functions, perhaps for debugging or for machine-specific performance.

This option may be specified more than once. The DT_AUXILIARY entries will be created in the order in which they appear on the command line. 💅

-F name, --filter=name — when creating an ELF shared object, set the internal DT_FILTER field to the specified name. This tells the dynamic linker that the symbol table of the shared object which is being created should be used as a filter on the symbol table of the shared object name. 🦋

If you later link a program against this filter object, then, when you run the program, the dynamic linker will see the DT_FILTER field. The dynamic linker will resolve symbols according to the symbol table of the filter object as usual, but it will actually link to the definitions found in the shared object name. Thus the filter object can be used to select a subset of the symbols provided by the object name.

Some older linkers used the -F option throughout a compilation toolchain for specifying object-file format for both input and output object files. The GNU linker uses other mechanisms for this purpose: the -b, --format, --oformat options, the "TARGET" command in linker scripts, and the "GNUTARGET" environment variable. The GNU linker will ignore the -F option when not creating an ELF shared object. 😭

-fini=name — when creating an ELF executable or shared object, call NAME when the executable or shared object is unloaded, by setting DT_FINI to the address of the function. By default, the linker uses "_fini" as the function to call. 🔥
-g — ignored. Provided for compatibility with other tools. literally just vibes 💀
-G value, --gpsize=value — set the maximum size of objects to be optimized using the GP register to size. This is only meaningful for object file formats such as MIPS ELF that support putting large and small objects into different sections. This is ignored for other object file formats. 👑
-h name, -soname=name — when creating an ELF shared object, set the internal DT_SONAME field to the specified name. When an executable is linked with a shared object which has a DT_SONAME field, then when the executable is run the dynamic linker will attempt to load the shared object specified by the DT_SONAME field rather than using the file name given to the linker. 🎀
-i — perform an incremental link (same as option -r). 🌈
-init=name — when creating an ELF executable or shared object, call NAME when the executable or shared object is loaded, by setting DT_INIT to the address of the function. By default, the linker uses "_init" as the function to call. ✨
-l namespec, --library=namespec — add the archive or object file specified by namespec to the list of files to link. This option may be used any number of times. If namespec is of the form :filename, ld will search the library path for a file called filename, otherwise it will search the library path for a file called libnamespec.a. 🫶

On systems which support shared libraries, ld may also search for files other than libnamespec.a. Specifically, on ELF and SunOS systems, ld will search a directory for a library called libnamespec.so before searching for one called libnamespec.a. (By convention, a ".so" extension indicates a shared library.) Note that this behavior does not apply to :filename, which always specifies a file called filename.

The linker will search an archive only once, at the location where it is specified on the command line. If the archive defines a symbol which was undefined in some object which appeared before the archive on the command line, the linker will include the appropriate file(s) from the archive. However, an undefined symbol in an object appearing later on the command line will not cause the linker to search the archive again. 😭

See the -( option for a way to force the linker to search archives multiple times.

You may list the same archive multiple times on the command line. 💅

Like, this kind of archive searching is standard for Unix linkers — periodt. But bestie, heads up: if you're using ld on AIX, it's genuinely different from how the AIX linker behaves. Not a vibe, just a fact. 💅

-L searchdir / --library-path=searchdir — adds searchdir to the list of paths ld searches for archive libraries and ld control scripts. Use it as many times as you want, no cap. ✨ Directories get searched in the order you put them on the command line, and command-line directories are searched before the default ones. Every -L applies to every -l, no matter what order the options show up in. Lowkey important: -L options don't affect how ld searches for a linker script unless you also specify the -T option.
- If searchdir starts with = or $SYSROOT, that prefix gets replaced by the sysroot prefix — controlled by --sysroot, or specified when the linker was configured. 🫶
- The default set of searched paths (the ones you didn't specify with -L) depends on which emulation mode ld is using, and in some cases on how it was configured.
- You can also specify paths inside a link script with the SEARCH_DIR command. Directories set that way get searched at the point where the linker script appears on the command line. iykyk 🌸
-m emulation — emulate the emulation linker. You can list the available emulations with --verbose or -V. 👑
- If -m isn't used, the emulation comes from the LDEMULATION environment variable — if that's defined.
- Otherwise, the default emulation depends on how the linker was configured.
--remap-inputs=pattern=filename / --remap-inputs-file=file — these let you change input file names before the linker even tries to open them. Iconic behaviour, honestly. So --remap-inputs=foo.o=bar.o makes any attempt to load a file called foo.o try to load bar.o instead. Wildcard patterns are allowed in the first filename, so --remap-inputs=foo*.o=bar.o renames any input file matching foo*.o to bar.o. 🦋
- --remap-inputs-file=filename is the alternate form: it reads the remappings from a file. Each line can contain a single remapping. Blank lines are ignored. Anything from a hash character (#) to the end of the line counts as a comment and is also ignored. The mapping pattern can be separated from the filename by whitespace or an equals (=) character.
- You can specify these options multiple times — their contents accumulate. Remappings get processed in the order they occur on the command line, and if they come from a file, in the order they occur in the file. If a match is made, no further checking for that filename happens. Done, next. 💅
- If the replacement filename is /dev/null or just NUL, the remapping actually makes the input file get ignored. Genuinely a convenient way to experiment with removing input files from a complicated build environment. 🙈
- Position-dependent alert: this option only affects filenames that come after it on the command line. So:

          ld foo.o --remap-inputs=foo.o=bar.o

will have, like, zero effect — whereas:

          ld --remap-inputs=foo.o=bar.o foo.o

will rename the input file foo.o to bar.o. Slay. ✨

Note — these options also affect files referenced by INPUT statements in linker scripts. But since linker scripts get processed after the entire command line is read, the position of the remap options on the command line is not significant.
If the verbose option is enabled, any mappings that match get reported — although again, the verbose option needs to be enabled on the command line before the remapped filenames appear.
If -Map or --print-map is enabled, the remapping list gets included in the map output. 🎀

-M, --print-map — prints a link map to standard output. A link map gives you info about the link, including all this:
- Where object files are mapped into memory.
- How common symbols are allocated.
- All archive members included in the link, with a mention of the symbol that caused the archive member to be brought in. 👀
- The values assigned to symbols.

Note — symbols whose values are computed by an expression that involves a reference to a previous value of the same symbol may not have the correct result displayed in the link map. Why? Because the linker discards intermediate results and only keeps the final value of an expression. In such situations the linker displays the final value enclosed by square brackets. So for example, a linker script containing:

foo = 1
foo = foo * 4
foo = foo + 8

will produce the following output in the link map if the -M option is used:

0x00000001                foo = 0x1
[0x0000000c]                foo = (foo * 0x4)
[0x0000000c]                foo = (foo + 0x8)

See Expressions for more info about expressions in linker scripts. 📖

How GNU properties are merged. When the linker merges input .note.gnu.property sections into one output .note.gnu.property section, some properties get removed or updated. These actions are reported in the link map. For example:

Removed property 0xc0000002 to merge foo.o (0x1) and bar.o (not found)

This indicates that property 0xc0000002 is removed from output when merging properties in foo.o, whose property 0xc0000002 value is 0x1, and bar.o, which doesn't have property 0xc0000002. 💀

Updated property 0xc0010001 (0x1) to merge foo.o (0x1) and bar.o (0x1)

This indicates that property 0xc0010001 value is updated to 0x1 in output when merging properties in foo.o, whose 0xc0010001 property value is 0x1, and bar.o, whose 0xc0010001 property value is 0x1. 🌈

On some ELF targets, a list of fixups inserted by --relax:

foo.o: Adjusting branch at 0x00000008 towards "far" in section .text

This indicates that the branch at 0x00000008 in foo.o, targeting the symbol "far" in section .text, has been replaced by a trampoline. 🔥

--print-map-discarded, --no-print-map-discarded — print (or do not print) the list of discarded and garbage collected sections in the link map. Enabled by default. 💖
--print-map-locals, --no-print-map-locals — print (or do not print) local symbols in the link map. Local symbols get the text (local) printed before their name, and get listed after all the global symbols in a given section. Temporary local symbols (typically the ones starting with .L) won't be included in the output. Disabled by default. 🌸
-n, --nmagic — turns off page alignment of sections, and disables linking against shared libraries. If the output format supports Unix style magic numbers, mark the output as "NMAGIC". ✨
-N, --omagic — sets the text and data sections to be readable and writable. Also, don't page-align the data segment, and disable linking against shared libraries. If the output format supports Unix style magic numbers, mark the output as "OMAGIC".

Note: although a writable text section is allowed for PE-COFF targets, it does not conform to the format specification published by Microsoft. ⚠️

--no-omagic — negates most of the effects of -N. It sets the text section to be read-only, and forces the data segment to be page-aligned.

Note — this option does not enable linking against shared libraries. Use -Bdynamic for that. 🫶

-o output / --output=output — use output as the name for the program ld produces; if you don't specify this option, the name a.out is used by default. The script command OUTPUT can also specify the output file name.

Note — the linker will delete the output file before it starts writing to it. It'll do this even if it turns out the link can't be completed due to errors. 😭 Note — the linker checks to make sure the output file name doesn't match the name of any of the input files, but that's all. In particular, it won't complain if the output file might overwrite a source file or some other important file. Therefore in build systems it's recommended to use -o as the last option on the linker command line. For example, consider:

ld -o $(EXE) $(OBJS)
ld $(OBJS) -o $(EXE)

If the EXE variable isn't defined for some reason, the first version of the linker command could end up deleting one of the object files (the first one in the OBJS list) — whereas the second version will generate an error message and not delete anything. Main character energy from the second one, honestly. 👑

--dependency-file=depfile — writes a dependency file to depfile. This file contains a rule suitable for make describing the output file and all the input files that were read to produce it. The output is similar to the compiler's output with -M -MP. 🎀
- Note that there's no option like the compiler's -MM to exclude "system files" (which is not a well-specified concept in the linker, unlike "system headers" in the compiler). So the output from --dependency-file is always specific to the exact state of the installation where it was produced, and should not be copied into distributed makefiles without careful editing. 💅
-O level — if level is a numeric value greater than zero, ld optimizes the output. This might take significantly longer and therefore probably should only be enabled for the final binary. At the moment this option only affects ELF shared library generation. Future releases of the linker may make more use of this option. Also, currently there's no difference in the linker's behaviour for different non-zero values of this option — again, this may change with future releases. ⭐
-O level continuation energy ✨ — so like, if level is zero or the string fast, then ld is gonna skip the optional stuff, which means a faster link but lowkey slower + bigger binaries. Right now the only thing it skips is combining mergeable sections, but bestie that could change in the future, no cap.

And if level is the string default or just the - character, you get the linker's default behaviour — neither optimizing nor skipping anything. Comfy middle ground 💅

-plugin name — pulls a plugin into the linking process 🫶. The name param is the absolute filename of the plugin. Usually your compiler adds this automatically when it's doing link time optimization, but honestly you can add your own plugins if you feel like it.

heads up bestie: compiler-originated plugins live somewhere different from where ar, nm and ranlib look for their plugins 😭. For those commands to use a compiler-based plugin, you gotta copy it into the ${libdir}/bfd-plugins directory first. Good news? All gcc-based linker plugins are backward compatible, so just copying in the newest one is literally enough. slay ✨

--push-state — saves the current state of all the flags that govern input file handling, so you can restore them all with one matching --pop-state. It's giving save point 🎀

The options covered are: -Bdynamic, -Bstatic, -dn, -dy, -call_shared, -non_shared, -static, -N, -n, --whole-archive, --no-whole-archive, --link-mapless, --no-link-mapless, -r, -Ur, --copy-dt-needed-entries, --no-copy-dt-needed-entries, --as-needed, --no-as-needed, and -a.

One iconic target for this option: pkg-config specifications 👑. When you use it with the --libs option, all possibly-needed libraries get listed and then possibly linked all the time. Way better to return something like this:

-Wl,--push-state,--as-needed -libone -libtwo -Wl,--pop-state

--pop-state — undoes the effect of --push-state, restoring the previous values of the flags governing input file handling. The undo button we deserve 🦋
-q, --emit-relocs — leaves relocation sections and their contents in fully linked executables. Post-link analysis and optimization tools might need this info to correctly modify executables. Side effect? Bigger executables. (trade-offs, am I right 💀)

currently this option is only supported on ELF platforms.

--force-dynamic — forces the output file to have dynamic sections. Very specific — this one's only for VxWorks targets 🌸
-r, --relocatable — generates relocatable output, i.e. it generates an output file that can itself serve as input to ld. We call this partial linking ✨. Fun side effect: in environments that support standard Unix magic numbers, this option also sets the output file's magic number to "OMAGIC". If you don't specify this option, you get an absolute file instead. And when you're linking C++ programs, this option will not resolve references to constructors — for that you want -Ur.

When an input file doesn't have the same format as the output file, partial linking is only supported if that input file contains no relocations. Different output formats can have further restrictions — for example, some "a.out"-based formats don't support partial linking with input files in other formats at all. 😭

When the relocatable output contains both contents which require link-time optimization (LTO) and contents which don't, a .gnu_object_only section gets created to contain a relocatable object file, as if -r is applied to all relocatable inputs which don't require LTO. And when the linker processes a relocatable input with a .gnu_object_only section, it extracts the .gnu_object_only section as a separate input 🧚

ngl, since -r groups some sections from different input files together, there may be negative impacts on code size and locality in the final executable or shared library. Keep that in mind 💜

This option does the same thing as -i.

-R filename, --just-symbols=filename — reads symbol names and their addresses from filename, but doesn't relocate it or include it in the output. This lets your output file refer symbolically to absolute locations of memory defined in other programs 🙈. You can use this option more than once.

For compatibility with other ELF linkers: if the -R option is followed by a directory name rather than a file name, it's treated as the -rpath option. (sneaky but iconic 🌈)

--rosegment, --no-rosegment — tries to make sure only a single read-only, non-code segment is created. Only useful when used with the -z separate-code option ✨. The resulting binaries should be smaller than if -z separate-code is used on its own. Without this option — or if --no-rosegment is specified — the -z separate-code option will create two read-only segments: one before the code segment and one after it.

the names of these options are misleading (💀), but they were chosen so the linker stays compatible with the LLD and GOLD linkers.

These options are only supported by ELF targets.

-s, --strip-all — omits all symbol information from the output file. bye symbols 👋
-S, --strip-debug — omits debugger symbol information from the output file (but not all symbols, okay?).
--strip-discarded, --no-strip-discarded — omits (or doesn't omit) global symbols defined in discarded sections. Enabled by default 🎀
-plugin-save-temps — stores the plugin "temporary" intermediate files permanently. Like, they're not temporary anymore bestie, they live here now 💅
-t, --trace — prints the names of the input files as ld processes them. Give -t twice and members within archives get printed too 🔥. -t output is genuinely useful for generating a list of all the object files and scripts involved in linking — for example when you're packaging files for a linker bug report.
-T scriptfile, --script=scriptfile — uses scriptfile as the linker script. This script replaces ld's default linker script (it doesn't add to it), unless the script contains "INSERT" — in which case commandfile must specify everything necessary to describe the output file 👑

If scriptfile doesn't exist in the current directory, ld looks for it in the directories specified by any preceding -L options.

Command line options that appear before the -T option can affect the script, but command line options that appear after it do not. (order matters, always 🌸)

Multiple -T options will accumulate if they're augmenting the current script — otherwise the last, non-augmenting, -T option is used.

There are other ways of specifying linker scripts. See

-dT scriptfile, --default-script=scriptfile — uses scriptfile as the default linker script 🦋.

This is like --script except that processing of the script is delayed until after the rest of the command line has been processed. That means options placed after --default-script on the command line can still affect the behaviour of the linker script — which is super important when the linker command line can't be directly controlled by the user (e.g. because the command line is being constructed by another tool, like gcc).

-u symbol, --undefined=symbol — forces symbol to be entered in the output file as an undefined symbol. Doing this may, for example, trigger linking of additional modules from standard libraries ✨. -u may be repeated with different option arguments to enter additional undefined symbols. This option is equivalent to the "EXTERN" linker script command.

if you're using this to force extra modules into the link, and it's an error for the symbol to remain undefined, use --require-defined instead, bestie 🙈

--require-defined=symbol — requires that symbol is defined in the output file. Same as --undefined except that if symbol isn't defined in the output file, the linker issues an error and exits 💀. You can get the same effect in a linker script by using "EXTERN", "ASSERT" and "DEFINED" together. Can be used multiple times to require additional symbols.
-Ur — for programs that don't use constructors or destructors, or for ELF-based systems, this option is equivalent to -r: it generates relocatable output, i.e. an output file that can itself serve as input to ld 🎀. For other binaries though, -Ur is similar to -r but it also resolves references to constructors and destructors.

on systems where -r and -Ur behave differently, it does not work to use -Ur on files that were themselves linked with -Ur — once the constructor table has been built, it cannot be added to 😭. Use -Ur only for the last partial link, and -r for the others. periodt.

--orphan-handling=MODE — controls how orphan sections are handled. An orphan section is one not specifically mentioned in a linker script 🧚.

MODE can have any of these values:

"place" — orphan sections are placed into a suitable output section following the strategy described in Orphan Sections. The --unique option also affects how sections are placed.
"discard" — all orphan sections are discarded, by placing them in the /DISCARD/ section.
"warn" — the linker places the orphan section as for "place" and also issues a warning.
"error" — the linker exits with an error if any orphan section is found.

If --orphan-handling isn't given, the default is "place" 💅

--unique[=SECTION] — creates a separate output section for every input section matching SECTION. If the optional wildcard SECTION argument is missing, it does this for every orphan input section instead (an orphan section being one not specifically mentioned in a linker script). You may use this option multiple times on the command line 🔥. It stops the normal merging of input sections with the same name, overriding output section assignments in a linker script. main character option energy, honestly 👑
-v, --version, -V — displays the version number for ld ✨. The -V option also lists the supported emulations. See also the description of the --enable-linker-version in Options,,Command-line Options, which can be used to insert the linker version string into a binary 🎀
-x, --discard-all — deletes all local symbols. gone, reduced to atoms 💀

okay bestie, picking right back up where we left off 💖

-X, --discard-locals — deletes all the temporary local symbols. These are the ones starting with system-specific local label prefixes — usually .L on ELF systems, or L on the old-school traditional a.out systems. Yeeted, gone, no cap 🗑️
-y symbol, --trace-symbol=symbol — prints the name of every linked file that symbol shows up in. You can pass this one as many times as you want, truly no limit. Heads up tho: on lots of systems you gotta stick an underscore in front of it 🙈

This one is lowkey a lifesaver when you've got an undefined symbol in your link and you're sitting there like "where is this reference even coming from?? 😭"

-Y path — adds path to the default library search path. It literally only exists for Solaris compatibility, so it's giving legacy vibes ✨
-z keyword — the keywords it recognizes are:
- call-nop=prefix-addr, call-nop=suffix-nop, call-nop=prefix-byte, call-nop=suffix-byte — specify the 1-byte "NOP" padding when transforming an indirect call to a locally defined function, foo, via its GOT slot. The way each one shakes out:
  - call-nop=prefix-addr generates "0x67 call foo".
  - call-nop=suffix-nop generates "call foo 0x90".
  - call-nop=prefix-byte generates "byte call foo".
  - call-nop=suffix-byte generates "call foo byte". Supported for i386 and x86_64. slay 🎀
- cet-report=none, cet-report=warning, cet-report=error — specify how to report the missing GNU_PROPERTY_X86_FEATURE_1_IBT and GNU_PROPERTY_X86_FEATURE_1_SHSTK properties in the input .note.gnu.property section. cet-report=none, which is the default, makes the linker not report missing properties in input files. cet-report=warning makes the linker issue a warning for missing properties in input files. cet-report=error makes the linker issue an error for missing properties in input files. Note that ibt will turn off the missing GNU_PROPERTY_X86_FEATURE_1_IBT property report and shstk will turn off the missing GNU_PROPERTY_X86_FEATURE_1_SHSTK property report. Supported for Linux/i386 and Linux/x86_64 💅
- combreloc, nocombreloc — combine multiple dynamic relocation sections and sort them to improve dynamic symbol lookup caching. Do not do this if nocombreloc. periodt ✋
- common, nocommon — generate common symbols with STT_COMMON type during a relocatable link. Use STT_OBJECT type if nocommon.
- common-page-size=value — set the page size most commonly used to value. The memory image layout will be optimized to minimize memory pages if the system is using pages of this size 🦋
- defs — report unresolved symbol references from regular object files. This happens even if the linker is creating a non-symbolic shared library. This option is the inverse of -z undefs 🔄
- dynamic-undefined-weak, nodynamic-undefined-weak — make undefined weak symbols dynamic when building a dynamic object, if they're referenced from a regular object file and not forced local by symbol visibility or versioning. Do not make them dynamic if nodynamic-undefined-weak. If neither option is given, a target may default to either option being in force, or make some other selection of undefined weak symbols dynamic. Fun fact: not all targets support these options 🙃
- execstack — marks the object as requiring executable stack.
- global — only meaningful when building a shared object. It makes the symbols defined by this shared object available for symbol resolution of subsequently loaded libraries 👑
- globalaudit — only meaningful when building a dynamic executable. It marks the executable as requiring global auditing by setting the "DF_1_GLOBAUDIT" bit in the "DT_FLAGS_1" dynamic tag. Global auditing requires that any auditing library defined via the --depaudit or -P command-line options be run for all dynamic objects loaded by the application.
- ibtplt — generate Intel Indirect Branch Tracking (IBT) enabled PLT entries. Supported for Linux/i386 and Linux/x86_64.
- ibt — generate GNU_PROPERTY_X86_FEATURE_1_IBT in the .note.gnu.property section to indicate compatibility with IBT. This also implies ibtplt. Supported for Linux/i386 and Linux/x86_64 🔥
- indirect-extern-access, noindirect-extern-access — generate GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS in the .note.gnu.property section to indicate that the object file requires canonical function pointers and cannot be used with copy relocation. This option also implies noextern-protected-data and nocopyreloc. Supported for i386 and x86-64.

noindirect-extern-access removes GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS from the .note.gnu.property section 🌸

initfirst — only meaningful when building a shared object. It marks the object so that its runtime initialization will occur before the runtime initialization of any other objects brought into the process at the same time. Similarly, the runtime finalization of the object will occur after the runtime finalization of any other objects. main character energy fr fr ✨
interpose — specify that the dynamic loader should modify its symbol search order so that symbols in this shared library interpose all other shared libraries not so marked.
unique, nounique — when generating a shared library or other dynamically loadable ELF object, mark it as one that should (by default) only ever be loaded once, and only in the main namespace (when using "dlmopen"). This is primarily used to mark fundamental libraries such as libc, libpthread et al which do not usually function correctly unless they are the sole instances of themselves. This behaviour can be overridden by the "dlmopen" caller and does not apply to certain loading mechanisms (such as audit libraries) 💅
lam-u48 — generate GNU_PROPERTY_X86_FEATURE_1_LAM_U48 in the .note.gnu.property section to indicate compatibility with Intel LAM_U48. Supported for Linux/x86_64.
lam-u57 — generate GNU_PROPERTY_X86_FEATURE_1_LAM_U57 in the .note.gnu.property section to indicate compatibility with Intel LAM_U57. Supported for Linux/x86_64.
lam-u48-report=none, lam-u48-report=warning, lam-u48-report=error — specify how to report the missing GNU_PROPERTY_X86_FEATURE_1_LAM_U48 property in the input .note.gnu.property section. lam-u48-report=none, which is the default, makes the linker not report missing properties in input files. lam-u48-report=warning makes the linker issue a warning for missing properties in input files. lam-u48-report=error makes the linker issue an error for missing properties in input files. Supported for Linux/x86_64 🧚
lam-u57-report=none, lam-u57-report=warning, lam-u57-report=error — specify how to report the missing GNU_PROPERTY_X86_FEATURE_1_LAM_U57 property in the input .note.gnu.property section. lam-u57-report=none, which is the default, makes the linker not report missing properties in input files. lam-u57-report=warning makes the linker issue a warning for missing properties in input files. lam-u57-report=error makes the linker issue an error for missing properties in input files. Supported for Linux/x86_64 🧚
lam-report=none, lam-report=warning, lam-report=error — specify how to report the missing GNU_PROPERTY_X86_FEATURE_1_LAM_U48 and GNU_PROPERTY_X86_FEATURE_1_LAM_U57 properties in the input .note.gnu.property section. lam-report=none, which is the default, makes the linker not report missing properties in input files. lam-report=warning makes the linker issue a warning for missing properties in input files. lam-report=error makes the linker issue an error for missing properties in input files. Supported for Linux/x86_64 💜
lazy — when generating an executable or shared library, mark it to tell the dynamic linker to defer function call resolution to the point when the function is actually called (lazy binding), rather than at load time. Lazy binding is the default, so this is very much the vibe 😴
loadfltr — specify that the object's filters be processed immediately at runtime.
max-page-size=value — set the maximum memory page size supported to value.
mark-plt, nomark-plt — mark PLT entries with dynamic tags, DT_X86_64_PLT, DT_X86_64_PLTSZ and DT_X86_64_PLTENT.

⚠️ okay real talk bestie: since this option stores a non-zero value in the r_addend field of R_X86_64_JUMP_SLOT relocations, the resulting executables and shared libraries are incompatible with dynamic linkers, such as those in older versions of glibc without the change to ignore r_addend in R_X86_64_GLOB_DAT and R_X86_64_JUMP_SLOT relocations, which don't ignore the r_addend field of R_X86_64_JUMP_SLOT relocations. Supported for x86_64. 💀

muldefs — allow multiple definitions. chaos, but sanctioned chaos 🙈
nocopyreloc — disable linker generated .dynbss variables used in place of variables defined in shared libraries. May result in dynamic text relocations.
nodefaultlib — specify that the dynamic loader search for dependencies of this object should ignore any default library search paths.
nodelete — specify that the object shouldn't be unloaded at runtime.
nodlopen — specify that the object is not available to "dlopen".
nodump — specify that the object can not be dumped by "dldump".
noexecstack — marks the object as not requiring executable stack.
noextern-protected-data — don't treat protected data symbols as external when building a shared library. This option overrides the linker backend default. It can be used to work around incorrect relocations against protected data symbols generated by compiler. Updates on protected data symbols by another module aren't visible to the resulting shared library. Supported for i386 and x86-64 🌈

okay so the -z keyword saga is still going and honestly it's kind of a lot, but we're gonna get through it together bestie 🫶

-z noreloc-overflow — turns OFF the relocation overflow check. Like, disables it completely. Only reach for this if there's genuinely not gonna be any dynamic relocation overflow at run-time, mmmkay? Supported for x86_64.
-z memory-seal, -z nomemory-seal — tells the executable or shared library that ALL the PT_LOAD segments should be sealed to avoid any further manipulation (think: changing the protection flags, the segment size, or straight up removing the mapping). It's a security hardening move and it needs system support to actually work. Generates GNU_PROPERTY_MEMORY_SEAL in the .note.gnu.property section. locked, sealed, delivered 💅
-z now — when generating an executable or shared library, marks it to tell the dynamic linker to resolve all symbols when the program is started, or when the shared library is loaded by dlopen, instead of deferring function call resolution to the point when the function is first called. no lazy vibes, everything resolved up front ✨
-z origin — specifies that the object requires $ORIGIN handling in paths.
-z pack-relative-relocs, -z nopack-relative-relocs — generates compact relative relocation in position-independent executables and shared libraries. It adds "DT_RELR", "DT_RELRSZ" and "DT_RELRENT" entries to the dynamic section. It gets ignored when you're building a position-dependent executable or relocatable output. nopack-relative-relocs is the default, which disables compact relative relocation. When linked against the GNU C Library, a GLIBC_ABI_DT_RELR symbol version dependency on the shared C Library is added to the output. Supported for i386 and x86-64. compact and cute 🎀
-z relro, -z norelro — creates an ELF "PT_GNU_RELRO" segment header in the object. This specifies a memory segment that should be made read-only after relocation, if that's supported. Heads up though: specifying common-page-size smaller than the system page size will render this protection ineffective 😭 so like, don't do that. With norelro, it does not create an ELF "PT_GNU_RELRO" segment.
-z report-relative-reloc — reports dynamic relative relocations generated by the linker. Supported for Linux/i386 and Linux/x86_64. receipts! 🧾
-z sectionheader, -z nosectionheader — generates the section header. Don't generate the section header if nosectionheader is used. sectionheader is the default, bestie.
-z separate-code, -z noseparate-code — creates a separate code "PT_LOAD" segment header in the object. This specifies a memory segment that should contain only instructions and must be in wholly disjoint pages from any other data. noseparate-code means don't create that separate code "PT_LOAD" segment.
-z shstk — generates GNU_PROPERTY_X86_FEATURE_1_SHSTK in the .note.gnu.property section to indicate compatibility with Intel Shadow Stack. Supported for Linux/i386 and Linux/x86_64. shadow stack said hi 👋
-z stack-size=value — specifies a stack size for an ELF "PT_GNU_STACK" segment. Specifying zero will override any default non-zero sized "PT_GNU_STACK" segment creation. yes, zero counts as a real answer here 🍓
-z start-stop-gc, -z nostart-stop-gc — okay this one's a whole paragraph so stay with me. When --gc-sections is in effect, a reference from a retained section to "__start_SECNAME" or "__stop_SECNAME" causes all input sections named "SECNAME" to also be retained, if "SECNAME" is representable as a C identifier and either "__start_SECNAME" or "__stop_SECNAME" is synthesized by the linker. -z start-stop-gc disables this effect, allowing sections to be garbage collected as if the special synthesized symbols were not defined. And importantly: -z start-stop-gc has no effect on a definition of "__start_SECNAME" or "__stop_SECNAME" in an object file or linker script. Such a definition will prevent the linker providing a synthesized "__start_SECNAME" or "__stop_SECNAME" respectively, and therefore the special treatment by garbage collection for those references. iykyk, it's giving very niche but very real ✨
-z start-stop-visibility=value — specifies the ELF symbol visibility for synthesized "__start_SECNAME" and "__stop_SECNAME" symbols. value must be exactly default, internal, hidden, or protected. If no -z start-stop-visibility option is given, protected is used for compatibility with historical practice. BUT — and this is the important part — it's highly recommended to use -z start-stop-visibility=hidden in new programs and shared libraries so that these symbols are not exported between shared objects, which is not usually what's intended. 💅
-z text, -z notext, -z textoff — reports an error if DT_TEXTREL is set, i.e. if the position-independent or shared object has dynamic relocations in read-only sections. With notext or textoff, don't report an error. text mode said "not today" 💀
-z undefs — do NOT report unresolved symbol references from regular object files, either when creating an executable or when creating a shared library. This option is the inverse of -z defs. the chill, forgiving one 🙈
-z unique-symbol, -z nounique-symbol — avoids duplicated local symbol names in the symbol string table. Appends "." followed by a number to duplicated local symbol names if unique-symbol is used. nounique-symbol is the default, so this is opt-in.
-z x86-64-baseline, -z x86-64-v2, -z x86-64-v3, -z x86-64-v4 — specifies the x86-64 ISA level needed in the .note.gnu.property section. x86-64-baseline generates "GNU_PROPERTY_X86_ISA_1_BASELINE". x86-64-v2 generates "GNU_PROPERTY_X86_ISA_1_V2". x86-64-v3 generates "GNU_PROPERTY_X86_ISA_1_V3". x86-64-v4 generates "GNU_PROPERTY_X86_ISA_1_V4". Supported for Linux/i386 and Linux/x86_64. pick your power level 🦋
-z isa-level-report=none, -z isa-level-report=all, -z isa-level-report=needed, -z isa-level-report=used — specifies how to report x86-64 ISA levels in input relocatable files. isa-level-report=none, which is the default, will make the linker not report x86-64 ISA levels in input files. isa-level-report=all will make the linker report needed and used x86-64 ISA levels in input files. isa-level-report=needed will make the linker report needed x86-64 ISA levels in input files. isa-level-report=used will make the linker report used x86-64 ISA levels in input files. Supported for Linux/i386 and Linux/x86_64. choose your gossip level ☕

also, heads up: other keywords are ignored, for Solaris compatibility. 🫶

--gnu-tls-tag, --no-gnu-tls-tag — adds a "GLIBC_ABI_GNU_TLS" version tag dependency in output programs and shared libraries when linking against glibc, if input relocatable object files call "___tls_get_addr". Fair warning: the output will fail to load and run at run-time against a glibc which doesn't define the "GLIBC_ABI_GNU_TLS" version tag 😭. Unless it's disabled by the --disable-gnu-tls-tag configure option at linker build time, when no options are specified the linker will add the "GLIBC_ABI_GNU_TLS" version tag dependency if inputs have a "___tls_get_addr" call and libc.so defines the "GLIBC_ABI_GNU_TLS" version tag. Supported for Linux/i386.
--gnu2-tls-tag, --no-gnu2-tls-tag — adds a "GLIBC_ABI_GNU2_TLS" version tag dependency in output programs and shared libraries when linking against glibc, if input relocatable object files have "R_386_TLS_DESC_CALL" or "R_X86_64_TLSDESC_CALL" relocation. Same deal here: the output will fail to load and run at run-time against a glibc which doesn't define the "GLIBC_ABI_GNU2_TLS" version tag. Unless it's disabled by the --disable-gnu2-tls-tag configure option at linker build time, when no options are specified the linker will add the "GLIBC_ABI_GNU2_TLS" version tag dependency if inputs have "R_386_TLS_DESC_CALL" or "R_X86_64_TLSDESC_CALL" relocation and libc.so defines the "GLIBC_ABI_GNU2_TLS" version tag. Supported for Linux/i386 and Linux/x86_64. the sequel tag, iconic behavior ✨
-( archives -), --start-group archives --end-group — archives should be a list of archive files. They may be either explicit file names, or -l options.

The specified archives are searched repeatedly until no new undefined references are created. Normally, an archive is searched only once, in the order that it is specified on the command line. If a symbol in that archive is needed to resolve an undefined symbol referred to by an object in an archive that appears later on the command line, the linker would not be able to resolve that reference. By grouping the archives, they'll all be searched repeatedly until all possible references are resolved. group project but it actually works 🫶

this option is not allowed within a --start-lib/--end-lib option pair.

also real talk: using this option has a significant performance cost. It's best to use it only when there are unavoidable circular references between two or more archives. 💀

--start-lib objects --end-lib — objects should be a list of object files.

The specified objects are treated as if they were members of an archive whose name has been placed at the location of --start-lib on the command line. All the usual linker archive handling properties and command line options apply to such an artificial archive. fake archive, real vibes 💅

This option may be used multiple times, in which case each set of the objects specified will be treated as an individual archive. Nesting this option is not allowed though — no inception, bestie 🙈.

Options that affect archive processing are not allowed between --start-lib and --end-lib, as it would make no sense to apply them midway through handling an archive. These options include: -(/--start-group, -)/--end-group, --whole-archive, and --no-whole-archive, as well as --pop-state where it would change the state of --whole-archive setting.

--accept-unknown-input-arch, --no-accept-unknown-input-arch — tells the linker to accept input files whose architecture can't be recognised. The assumption is that the user knows what they're doing and deliberately wants to link in these unknown input files 👑. This was the default behaviour of the linker before release 2.14. The default behaviour from release 2.14 onwards is to reject such input files, which is why the --accept-unknown-input-arch option has been added — to restore the old behaviour. vintage mode unlocked ⭐
--as-needed, --no-as-needed — okay so this one is about ELF DT_NEEDED tags for dynamic libs you list on the command line after --as-needed shows up ✨. Normally the linker is a little extra and slaps a DT_NEEDED tag on for every dynamic library you mention, whether it's actually needed or not (rude, honestly). --as-needed is the vibe check: it only emits a DT_NEEDED tag for a library that, at that point in the link, satisfies a non-weak undefined symbol reference from a regular object file — or, if the library isn't found in the DT_NEEDED lists of other needed libraries, a non-weak undefined symbol reference from another needed dynamic library 🫶. And bestie, object files or libraries that appear on the command line after the library in question do not affect whether it's seen as needed — very "your opinion is noted but irrelevant" 💅. It's similar to the rules for extraction of object files from archives. --no-as-needed restores the default behaviour, no cap.

Note 🎀: on Linux based systems the --as-needed option also has an affect on the behaviour of the --rpath and --rpath-link options. See the description of --rpath-link for more details.

--add-needed, --no-add-needed — these two are deprecated 😭 literally because their names were too similar to --as-needed and --no-as-needed and everyone kept getting confused. They've been replaced by --copy-dt-needed-entries and --no-copy-dt-needed-entries. Use the new ones, iykyk.
-assert keyword — this option is ignored for SunOS compatibility 🦋. That's it. It's just sitting there. Iconic of it honestly.
-Bdynamic, -dy, -call_shared — link against dynamic libraries 💖. This is only meaningful on platforms for which shared libraries are supported, and it's normally the default on those platforms anyway. The different variants of this option exist for compatibility with various systems (so many little aliases, they ate). You may use this option multiple times on the command line: it affects library searching for -l options which follow it ✨.
-Bgroup — sets the DF_1_GROUP flag in the DT_FLAGS_1 entry in the dynamic section 👑. This makes the runtime linker handle lookups in this object and its dependencies as something to be performed only inside the group. --unresolved-symbols=report-all is implied. Only meaningful on ELF platforms which support shared libraries 🦋.
-Bstatic, -dn, -non_shared, -static — the opposite energy: do not link against shared libraries 💀. Only meaningful on platforms for which shared libraries are supported. The different variants are for compatibility with various systems. You may use this option multiple times on the command line: it affects library searching for -l options which follow it. This option also implies --unresolved-symbols=report-all. Fun fact: this option can be used with -shared — doing so means a shared library is being created but that all of the library's external references must be resolved by pulling in entries from static libraries 🔥. Chaotic combo but it works.
-Bsymbolic — when creating a shared library, bind references to global symbols to the definition within the shared library, if any 🌸. Normally it's possible for a program linked against a shared library to override the definition within the shared library — this option says "no bestie, we're keeping it in-house" 💅. Only meaningful on ELF platforms which support shared libraries.
-Bsymbolic-functions — same idea as -Bsymbolic but only for global function symbols: bind references to them to the definition within the shared library, if any ✨. Only meaningful on ELF platforms which support shared libraries.
-Bno-symbolic — this one can cancel previously specified -Bsymbolic and -Bsymbolic-functions 🫶. A little undo button, we love to see it.
--dynamic-list=dynamic-list-file — tells the linker the name of a dynamic list file 📄. This is typically used when creating shared libraries to specify a list of global symbols whose references shouldn't be bound to the definition within the shared library, or when creating dynamically linked executables to specify a list of symbols which should be added to the symbol table in the executable. Only meaningful on ELF platforms which support shared libraries 🦋.

The format of the dynamic list is the same as the version node without scope and node name. See VERSION for more information 👀.

--dynamic-list-data — include all global data symbols to the dynamic list ✨. Short, sweet, slay.
--dynamic-list-cpp-new — provides the builtin dynamic list for C++ operator new and delete 🎀. It's mainly useful for building shared libstdc++.
--dynamic-list-cpp-typeinfo — provides the builtin dynamic list for C++ runtime type identification 👑.
--check-sections, --no-check-sections — --no-check-sections asks the linker not to check section addresses after they have been assigned to see if there are any overlaps 🙈. Normally the linker will perform this check, and if it finds any overlaps it will produce suitable error messages (as it should!). The linker does know about, and does make allowances for, sections in overlays. The default behaviour can be restored by using the command-line switch --check-sections 💅. Section overlap is not usually checked for relocatable links — you can force checking in that case by using the --check-sections option ✨.
--copy-dt-needed-entries, --no-copy-dt-needed-entries — this affects the treatment of dynamic libraries referred to by DT_NEEDED tags inside ELF dynamic libraries mentioned on the command line 🦋. Normally the linker won't add a DT_NEEDED tag to the output binary for each library mentioned in a DT_NEEDED tag in an input dynamic library. With --copy-dt-needed-entries specified on the command line however, any dynamic libraries that follow it will have their DT_NEEDED entries added ✨. The default behaviour can be restored with --no-copy-dt-needed-entries.

This option also has an effect on the resolution of symbols in dynamic libraries 👀. With --copy-dt-needed-entries, dynamic libraries mentioned on the command line will be recursively searched, following their DT_NEEDED tags to other libraries, in order to resolve symbols required by the output binary. With the default setting however, the searching of dynamic libraries that follow it will stop with the dynamic library itself — no DT_NEEDED links will be traversed to resolve symbols 💅.

--cref — outputs a cross reference table 📊. If a linker map file is being generated, the cross reference table is printed to the map file. Otherwise, it's printed on the standard output ✨.

The format of the table is intentionally simple, so that it may be easily processed by a script if necessary (considerate king 👑). The symbols are printed out, sorted by name. For each symbol, a list of file names is given. If the symbol is defined, the first file listed is the location of the definition. If the symbol is defined as a common value then any files where this happens appear next. Finally any files that reference the symbol are listed 🫶.

--ctf-variables, --no-ctf-variables — the CTF debuginfo format supports a section which encodes the names and types of variables found in the program which do not appear in any symbol table 🌸. These variables clearly cannot be looked up by address by conventional debuggers, so the space used for their types and names is usually wasted: the types are usually small but the names are often not 😭. --ctf-variables causes the generation of such a section. The default behaviour can be restored with --no-ctf-variables 💅.
--ctf-share-types=method — adjusts the method used to share types between translation units in CTF ✨. The methods are:
- share-unconflicted — put all types that do not have ambiguous definitions into the shared dictionary, where debuggers can easily access them, even if they only occur in one translation unit 💖. This is the default.
- share-duplicated — put only types that occur in multiple translation units into the shared dictionary: types with only one definition go into per-translation-unit dictionaries 🦋. Types with ambiguous definitions in multiple translation units always go into per-translation-unit dictionaries. This tends to make the CTF larger, but may reduce the amount of CTF in the shared dictionary. For very large projects this may speed up opening the CTF and save memory in the CTF consumer at runtime 🔥.
--no-define-common — this option inhibits the assignment of addresses to common symbols 🙅. The script command INHIBIT_COMMON_ALLOCATION has the same effect.

The --no-define-common option allows decoupling the decision to assign addresses to Common symbols from the choice of the output file type; otherwise a non-Relocatable output type forces assigning addresses to Common symbols 👀. Using --no-define-common allows Common symbols that are referenced from a shared library to be assigned addresses only in the main program. This eliminates the unused duplicate space in the shared library, and also prevents any possible confusion over resolving to the wrong duplicate when there are many dynamic modules with specialized search paths for runtime symbol resolution 🎀.

--force-group-allocation — this option causes the linker to place section group members like normal input sections, and to delete the section groups 🫶. This is the default behaviour for a final link, but this option can be used to change the behaviour of a relocatable link (-r). The script command FORCE_GROUP_ALLOCATION has the same effect ✨.
--defsym=symbol=expression — creates a global symbol in the output file, containing the absolute address given by expression 👑. You may use this option as many times as necessary to define multiple symbols in the command line. A limited form of arithmetic is supported for the expression in this context: you may give a hexadecimal constant or the name of an existing symbol, or use + and - to add or subtract hexadecimal constants or symbols 🦋. If you need more elaborate expressions, consider using the linker command language from a script.

Note bestie 📢: there should be no white space between symbol, the equals sign (=), and expression. The linker will not forgive the space. It never does 😭.

...okay so real talk, the linker handles --defsym args and -T args in order ✨ — like, it literally goes through them one by one, in the order you typed them. So bestie, if you put --defsym before -T, the symbol gets defined before the linker script from -T gets processed. But if you put --defsym after -T? Then the symbol gets defined after the linker script has already been processed 👀. And no, this isn't a whatever-detail — this difference has actual consequences for expressions inside the linker script that use the --defsym symbols 💅. Which order is the "correct" one totally depends on what you're trying to achieve. iykyk.

--demangle[=style], --no-demangle — these control whether symbol names get demangled in error messages and other output 🎀. When you tell the linker to demangle, it tries to show symbol names in a readable way: it strips leading underscores if the object file format uses them, and converts C++ mangled symbol names into names us humans can actually read 😭. Different compilers have different mangling styles, so the optional style argument lets you pick the demangling style that matches your compiler. Default behavior: the linker demangles unless the environment variable COLLECT_NO_DEMANGLE is set. These options override that default 🦋.
-Ifile, --dynamic-linker=file — sets the name of the dynamic linker. This is only meaningful when you're generating dynamically linked ELF executables. The default dynamic linker is normally correct, so like... don't use this unless you know what you're doing 🙈 (genuine warning, not a vibe).
--no-dynamic-linker — when producing an executable file, omit the request for a dynamic linker to be used at load-time. Only meaningful for ELF executables that contain dynamic relocations, and it usually requires entry point code that's capable of processing those relocations 💀.
--embedded-relocs — similar to --emit-relocs, except the relocs are stored in a target-specific section. Only supported by the BFIN, CR16 and M68K targets 👑.
--disable-multiple-abs-defs — do not allow multiple definitions with symbols included in filename invoked by -R or --just-symbols 🫶.
--fatal-warnings, --no-fatal-warnings — treat all warnings as errors 😳. You can restore the default behavior with --no-fatal-warnings.
-w, --no-warnings — do not display any warning or error messages. This overrides --fatal-warnings if that's been enabled. Use it when you already know the output binary won't work but you still need to create it anyway 💀 (yes, that's the actual use case).
--force-exe-suffix — makes sure the output file has a .exe suffix. If a successfully built, fully linked output file doesn't have a .exe or .dll suffix, this option forces the linker to copy the output file to one of the same name with a .exe suffix. Super useful when you're using unmodified Unix makefiles on a Microsoft Windows host, because some versions of Windows won't run an image unless it ends in .exe 🍓.

--gc-sections, --no-gc-sections — enable garbage collection of unused input sections ✨. It's ignored on targets that don't support it. You can restore the default (i.e. not doing this garbage collection) by passing --no-gc-sections on the command line. Heads up: garbage collection for COFF and PE format targets is supported, but the implementation is currently considered experimental 🙈.

So how does --gc-sections decide which input sections get used? It examines symbols and relocations 🔍. The section containing the entry symbol is kept, along with all sections containing symbols undefined on the command-line, and sections containing symbols referenced by dynamic objects. Note that when building shared libraries, the linker must assume that any visible symbol is referenced 👀. Once that initial set of sections is figured out, the linker recursively marks as used any section referenced by their relocations. Go check --entry, --undefined, and --gc-keep-exported for the details.

You can also set this option when doing a partial link (enabled with the -r option). In that case, the root of symbols kept must be explicitly specified — either by one of --entry, --undefined, or --gc-keep-exported, or by an ENTRY command in the linker script 🎀.

As a GNU extension, ELF input sections marked with the SHF_GNU_RETAIN flag will not be garbage collected 🛡️.

--print-gc-sections, --no-print-gc-sections — list all sections removed by garbage collection, printed on stderr. Only effective if garbage collection has been enabled via the --gc-sections option. Default behavior (not listing removed sections) can be restored with --no-print-gc-sections on the command line 💅.
--gc-keep-exported — when --gc-sections is enabled, this stops garbage collection of unused input sections that contain global symbols with default or protected visibility. It's meant for executables where unreferenced sections would otherwise get garbage collected regardless of the external visibility of contained symbols. Ngl, this option has no effect when linking shared objects, since that's already the default behavior there. Only supported for ELF format targets 🌈.
--print-output-format — print the name of the default output format (which might be influenced by other command-line options). This is the string that would show up in an OUTPUT_FORMAT linker script command ⭐.
--print-memory-usage — print used size, total size and used size of memory regions created with the MEMORY command. Super handy on embedded targets to get a quick view of how much free memory you have left 🧚. The output format has one headline and one line per region, and it's both human readable and easily parsable by tools. Example output:

        Memory region         Used Size  Region Size  %age Used
                     ROM:        256 KB         1 MB     25.00%
                     RAM:          32 B         2 GB      0.00%

Note: if you wanna find out the memory usage of the linker itself, the --stats option does that 💖.

--help — print a summary of the command-line options on standard output and exit. iconic.
--target-help — print a summary of all target-specific options on standard output and exit ✨.
-Map=mapfile — print a link map to the file mapfile. See the description of the -M option above. If mapfile is just the character -, the map gets written to stdout 🦋.

Specifying a directory as mapfile causes the linker map to be written as a file inside that directory. Normally the name of the file inside the directory is computed as the basename of the output file with .map appended. But if the special character % is used, that gets replaced by the full path of the output file 🔥. And additionally, if there are any characters after the % symbol, then .map is no longer appended.

 -o foo.exe -Map=bar                  [Creates ./bar]
 -o ../dir/foo.exe -Map=bar           [Creates ./bar]
 -o foo.exe -Map=../dir               [Creates ../dir/foo.exe.map]
 -o ../dir2/foo.exe -Map=../dir       [Creates ../dir/foo.exe.map]
 -o foo.exe -Map=%                    [Creates ./foo.exe.map]
 -o ../dir/foo.exe -Map=%             [Creates ../dir/foo.exe.map]
 -o foo.exe -Map=%.bar                [Creates ./foo.exe.bar]
 -o ../dir/foo.exe -Map=%.bar         [Creates ../dir/foo.exe.bar]
 -o ../dir2/foo.exe -Map=../dir/%     [Creates ../dir/../dir2/foo.exe.map]
 -o ../dir2/foo.exe -Map=../dir/%.bar [Creates ../dir/../dir2/foo.exe.bar]

It is an error to specify more than one % character 💀.

And if the map file already exists, it will be overwritten by this operation. (Fair warning, bestie 😭.)

--no-keep-memory — ld normally optimizes for speed over memory usage by caching the symbol tables of input files in memory. This option tells ld to optimize for memory usage instead, by re-reading the symbol tables as necessary. Might be needed if ld runs out of memory space while linking a large executable 🫶.
--no-undefined, -z defs — report unresolved symbol references from regular object files 📢. This happens even if the linker is creating a non-symbolic shared library. The switch --[no-]allow-shlib-undefined controls the behavior for reporting unresolved references found in shared libraries being linked in. You can revert the effects of this option by using -z undefs 👑
--allow-multiple-definition, -z muldefs — normally, when a symbol is defined multiple times, the linker reports a fatal error 😳. These options allow multiple definitions, and the first definition will be used.
--allow-shlib-undefined, --no-allow-shlib-undefined — allows or disallows undefined symbols in shared libraries. Similar to --no-undefined, except this one decides the behavior when the undefined symbols are in a shared library rather than a regular object file 💅. It does not affect how undefined symbols in regular object files are handled.

Default behavior: report errors for any undefined symbols referenced in shared libraries if the linker is being used to create an executable, but allow them if the linker is being used to create a shared library ✨.

The reasons for allowing undefined symbol references in shared libraries specified at link time are:

A shared library specified at link time may not be the same as the one available at load time, so the symbol might actually be resolvable at load time 👀.
There are some operating systems, eg BeOS and HPPA, where undefined symbols in shared libraries are normal.

The BeOS kernel, for example, patches shared libraries at load time to select whichever function is most appropriate for the current architecture. This is used, for example, to dynamically select an appropriate memset function 🌸.

--error-handling-script=scriptname — okay so if you pass this, the linker invokes scriptname whenever it hits an error. Currently only two kinds of error are supported: missing symbols and missing libraries. Two arguments get passed to script: the keyword "undefined-symbol" or missing-lib" and the name of the undefined symbol or missing library. The whole intention is that the script gives the user suggestions about where that symbol or library might be found. After the script has finished, the normal linker error message is displayed. 🫶

The availability of this option is controlled by a configure time switch, so it may not be present in specific implementations. 😭

--no-undefined-version — normally, when a symbol has an undefined version, the linker just ignores it. This option says nope, not today: symbols with undefined version are disallowed and a fatal error is issued instead. 💅
--default-symver — create and use a default symbol version (the soname) for unversioned exported symbols. slay.
--default-imported-symver — same vibe, but for unversioned imported symbols: create and use a default symbol version (the soname). ✨
--no-warn-mismatch — normally ld gives an error if you try to link together input files that are mismatched for some reason, maybe because they were compiled for different processors or for different endiannesses. This option tells ld to silently permit such possible errors. Use with care only when you’ve taken some special action that ensures the linker errors are inappropriate. 🫣
--no-warn-search-mismatch — normally ld gives a warning if it finds an incompatible library during a library search. This option silences that warning. quiet girl behavior, lowkey.
--no-whole-archive — turn off the effect of the --whole-archive option for subsequent archive files. Not allowed within a --start-lib/--end-lib option pair. no cap.
--no-link-mapless — reject archives that lack an index aka symbol map for all the subsequent archives referred on the command line. If such a file is encountered, a link error occurs. This is the traditional behavior. fr fr.
--noinhibit-exec — retain the executable output file whenever it is still usable. Normally, the linker will not produce an output file if it encounters errors during the link process; it exits without writing an output file when it issues any error whatsoever. this one’s giving “keep the messy draft anyway” energy. 💀
-nostdlib — only search library directories explicitly specified on the command line. Library directories specified in linker scripts (including linker scripts specified on the command line) are ignored. periodt.
--oformat=output-format — ld may be configured to support more than one kind of object file. If your ld is configured this way, you can use --oformat to specify the binary format for the output object file. Even when ld is configured to support alternative object formats, you don’t usually need to specify this, as ld should be configured to produce as a default output format the most usual format on each machine. output-format is a text string, the name of a particular format supported by the BFD libraries. (You can list the available binary formats with objdump -i.) The script command OUTPUT_FORMAT can also specify the output format, but this option overrides it. 👑
--out-implib file — create an import library in file corresponding to the executable the linker is generating (eg. a DLL or ELF program). This import library (which should be called *.dll.a or *.a for DLLs) may be used to link clients against the generated executable; this behaviour makes it possible to skip a separate import library creation step (eg. dlltool for DLLs). This option is only available for the PE and ELF targetted ports of the linker. 🎀
-pie, --pic-executable — create a position independent executable. This is currently only supported on ELF platforms. Position independent executables are relocated by the dynamic linker to the virtual address the OS chooses for them, which can vary between invocations. They are marked ET_DYN in the ELF file header, but differ from shared libraries in a number of ways. In particular, defined symbols in a PIE by default can not be overridden by another object as they can be in a shared library. main character energy but relocated. 🦋
-no-pie — create a position dependent executable. This is the default. back to basics, bestie.
-qmagic — this option is ignored for Linux compatibility. literally just there for the vibe.
-Qy — this option is ignored for SVR4 compatibility. also just vibing. 💜
--relax, --no-relax — an option with machine dependent effects. This option is only supported on a few targets. 👀

On some platforms the --relax option performs target specific, global optimizations that become possible when the linker resolves addressing in the program, such as relaxing address modes, synthesizing new instructions, selecting shorter version of current instructions, and combining constant values.

On some platforms these link time global optimizations may make symbolic debugging of the resulting executable impossible. This is known to be the case for the Matsushita MN10200 and MN10300 family of processors. not me learning that the hard way 😭

On platforms where the feature is supported, the option --no-relax will disable it.

On platforms where the feature is not supported, both --relax and --no-relax are accepted, but ignored. iconic “we listen and we don’t judge” behavior.

--retain-symbols-file=filename — retain only the symbols listed in the file filename, discarding all others. filename is simply a flat file, with one symbol name per line. This option is especially useful in environments (such as VxWorks) where a large global symbol table is accumulated gradually, to conserve run-time memory. memory queen behavior ✨

--retain-symbols-file does not discard undefined symbols, or symbols needed for relocations.

You may only specify --retain-symbols-file once in the command line. It overrides -s and -S. no duplicating, bestie.

-rpath=dir — add a directory to the runtime library search path. This is used when linking an ELF executable with shared objects. All -rpath arguments are concatenated and passed to the runtime linker, which uses them to locate shared objects at runtime. 🫶

The -rpath option is also used when locating shared objects which are needed by shared objects explicitly included in the link; see the description of the -rpath-link option. Searching -rpath in this way is only supported by native linkers and cross linkers which have been configured with the --with-sysroot option.

If -rpath is not used when linking an ELF executable, the contents of the environment variable LD_RUN_PATH will be used if it is defined.

The -rpath option may also be used on SunOS. By default, on SunOS, the linker will form a runtime search path out of all the -L options it is given. If a -rpath option is used, the runtime search path will be formed exclusively using the -rpath options, ignoring the -L options. This can be useful when using gcc, which adds many -L options which may be on NFS mounted file systems.

For compatibility with other ELF linkers, if the -R option is followed by a directory name, rather than a file name, it is treated as the -rpath option. iykyk. 💅

-rpath-link=dir — when using ELF or SunOS, one shared library may require another. This happens when an ld -shared link includes a shared library as one of the input files. 🌀

When the linker encounters such a dependency when doing a non-shared, non-relocatable link, it will automatically try to locate the required shared library and include it in the link, if it is not included explicitly. In such a case, several directories are searched as described below. The -rpath-link option specifies the first set of directories to search. This option may specify a sequence of directory names either by providing a list of names separated by colons, or by appearing multiple times.

The tokens $ORIGIN and $LIB can appear in these search directories. They will be replaced by the full path to the directory containing the program or shared object in the case of $ORIGIN and either lib — for 32-bit binaries — or lib64 — for 64-bit binaries — in the case of $LIB.

The alternative form of these tokens — ${ORIGIN} and ${LIB} — can also be used. The token $PLATFORM is not supported. do not come for me with $PLATFORM, it’s not invited 🙈

The --rpath-link option should be used with caution as it overrides the search path that may have been hard compiled into a shared library. In such a case it is possible to unintentionally use a different search path than the runtime linker would have used. ⚠️

When additional shared libraries are required, the linker will search directories in the order listed below in order to find them. Note however that this only applies to additional libraries needed to satisfy already included shared libraries. It does not apply to libraries that are included via the -l command line option. Searches for -l libraries are only conducted in directories specified by the -L option.

Any directories specified by -rpath-link options.
Any directories specified by -rpath options. The difference between -rpath and -rpath-link is that directories specified by -rpath options are included in the executable and used at runtime, whereas the -rpath-link option is only effective at link time. Searching -rpath in this way is only supported by native linkers and cross linkers which have been configured with the --with-sysroot option.
On an ELF system, for native linkers, if the -rpath and -rpath-link options were not used, search the contents of the environment variable LD_RUN_PATH.
On SunOS, if the -rpath option was not used, search any directories specified using -L options.
For a native linker, search the contents of the environment variable LD_LIBRARY_PATH.
For a native ELF linker, the directories in DT_RUNPATH or DT_RPATH of a shared library are searched for shared libraries needed by it. The DT_RPATH entries are ignored if DT_RUNPATH entries exist. the way that search order ate, honestly 💚

Linux linker era — if the file /etc/ld.so.conf exists, the list of directories found in that file is in the mix. Tiny side-quest: the path to this file is prefixed with the "sysroot" value, if that is defined, and then any "prefix" string if the linker was configured with the --prefix=<path> option. 🐧
FreeBSD native linker bestie — any directories specified by the "_PATH_ELF_HINTS" macro defined in the elf-hints.h header file. 🦋
Any directories specified by a "SEARCH_DIR" command in a linker script given on the command line, including scripts specified by -T (but not -dT). 📜
The default directories, normally /lib and /usr/lib. Classic. 🏠
Any directories specified by a plugin LDPT_SET_EXTRA_LIBRARY_PATH. Plugins stay doing the most. 🔌
Any directories specified by a "SEARCH_DIR" command in a default linker script. ✨

⚠️ Linux plot twist, no cap: if the --as-needed option is active and a shared library is located which would normally satisfy the search and this library does not have DT_NEEDED tag for libc.so, and there is a shared library later on in the set of search directories which also satisfies the search and this second shared library does have a DT_NEEDED tag for libc.so, then the second library will be selected instead of the first. 😭

If the required shared library is not found, the linker will issue a warning and continue with the link. It's giving "we move." 💅

--section-ordering-file=script — This option is used to augment the current linker script with additional mapping of input sections to output sections. This file must use the same syntax for SECTIONS as is used in normal linker scripts, but it should not do anything other than place input sections into output sections. @pxref{SECTIONS}

A second constraint on the section ordering script is that it can only reference output sections that are already defined by whichever linker script is currently in use. (Ie the default linker script or a script specified on the command line). The benefit of the section ordering script however is that the input sections are mapped to the start of the output sections, so that they can ensure the ordering of sections in the output section. For example, imagine that the default linker script looks like this:

                   SECTIONS {
                     .text : { *(.text.hot) ; *(.text .text.*) }
                     .data : { *(.data.big) ; *(.data .data.*) }
                     }

Then if a section ordering file like this is used:

                     .text : { *(.text.first) ; *(.text.z*) }
                     .data : { foo.o(.data.first) ; *(.data.small) }

This would be equivalent to a linker script like this:

                   SECTIONS {
                     .text : { *(.text.first) ; *(.text.z*) ; *(.text.hot) ; *(.text .text.*) }
                     .data : { foo.o(.data.first) ; *(.data.small) ; *(.data.big) ; *(.data .data.*) }
                     }

The advantage of the section ordering file is that it can be used to order those sections that matter to the user without having to worry about any other sections, or memory regions, or anything else. iconic behavior, honestly 🌈

-shared, -Bshareable — Create a shared library. This is currently only supported on ELF, XCOFF and SunOS platforms. On SunOS, the linker will automatically create a shared library if the -e option is not used and there are undefined symbols in the link. 🫶
--sort-common, --sort-common=ascending, --sort-common=descending — This option tells ld to sort the common symbols by alignment in ascending or descending order when it places them in the appropriate output sections. The symbol alignments considered are sixteen-byte or larger, eight-byte, four-byte, two-byte, and one-byte. This is to prevent gaps between symbols due to alignment constraints. If no sorting order is specified, then descending order is assumed. lowkey tidy ✨
--sort-section=name — This option will apply "SORT_BY_NAME" to all wildcard section patterns in the linker script. 🏷️
--sort-section=alignment — This option will apply "SORT_BY_ALIGNMENT" to all wildcard section patterns in the linker script. 📐
--spare-dynamic-tags=count — This option specifies the number of empty slots to leave in the .dynamic section of ELF shared objects. Empty slots may be needed by post processing tools, such as the prelinker. The default is 5. 🎀
--split-by-file[=size] — Similar to --split-by-reloc but creates a new output section for each input file when size is reached. size defaults to a size of 1 if not given. 🍓
--split-by-reloc[=count] — Tries to creates extra sections in the output file so that no single output section in the file contains more than count relocations. This is useful when generating huge relocatable files for downloading into certain real time kernels with the COFF object file format; since COFF cannot represent more than 65535 relocations in a single section. Note that this will fail to work with object file formats which do not support arbitrary sections. The linker will not split up individual input sections for redistribution, so if a single input section contains more than count relocations one output section will contain that many relocations. count defaults to a value of 32768. 💀
--stats[=filename] — Compute and display statistics about the operation of the linker, such as execution time and memory usage.

If the optional filename argument is not supplied then only basic information is reported, and it is sent to the standard error output stream. If the filename argument is supplied then extended information is written to the named file. If filename is set to just the - symbol, then the extended information is sent to the standard output stream. If the filename starts with + then the file is opened in append mode rather than overwrite mode.

If the -Map option has been enabled then the information is also recorded in the map file as well. Note: if both the --stats option and the -Map options have been given filename arguments and they match, then the information will only be written out once not twice.

If the "LD_STATS" environment variable is defined then this behaves likes the --stats option. If the variable's value is a string then this will used as the name of a file into which the information should be recorded. Otherwise the information will be sent to the standard output stream. Using the environment variable allows stats to be recorded without having to alter the linker's command line. Note: if both the environment variable and the --stats option are used then the --stats option takes precedence.

The extended information reported includes the cpu time used and, if the getrusage() system library call is available then maximum set size and the user and system run times as well. In addition if the mallinfo or mallinfo2 system library calls are available then the total memory usage is reported,

The information is displayed for individual parts of the linking process which are referred to as phases. Note that individual phases can contain or overlap with each other so it should not be assumed that the overall resources used by the linker is the sum of the resources used by the individual phases.

In addition the information is also reported for a special phase called ALL which covers the entire linking process.

When extended information is being reported the linker version, command line arguments and linker start time are also included. This makes it easier to handle the situation where multiple links are being invoked by a build system and to identify exactly which arguments were responsible for producing the statistics that are reported.

The extended output looks something like this:

                   Stats: linker version: (GNU Binutils) 2.44.50.20250401
                   Stats: linker started: Wed Apr  2 09:36:41 2025
                   Stats: args: ld -z norelro -z nomemory-seal -z no-separate-code -o a.out [...]

                   Stats: phase               cpu time       rss      user time    system time     memory
                   Stats: name                (microsec)   (KiB)      (seconds)      (seconds)      (KiB)
                   Stats: ALL                   390082    217740              0              0   25219440
                   Stats: ctf processing            12         0              0              0          0
                   Stats: string merge            1324         0              0              0     406544
                   Stats: parsing                  349       288              0              0     119792
                   Stats: plugins                    1         0              0              0          0
                   Stats: processing files      259616    214524              0              0   31569120
                   Stats: write                 116493         0              0              0      48096

--no-stats — Disables the reporting of usage statistics, should it have been enabled via the --stats command line option or the LD_STATS environment variable. 🙈
--sysroot=directory — Use directory as the location of the sysroot, overriding the configure-time default. This option is only supported by linkers that were configured using --with-sysroot. 🧚
--task-link — This is used by COFF/PE based targets to create a task-linked object file where all of the global symbols have been converted to statics. 👑
--traditional-format — For some targets, the output of ld is different in some ways from the output of some existing linker. This switch requests ld to use the traditional format instead.

For example, on SunOS, ld combines duplicate entries in the symbol string table. This can reduce the size of an output file with full debugging information by over 30 percent. Unfortunately, the SunOS "dbx" program can not read the resulting program ("gdb" has no trouble). The --traditional-format switch tells ld to not combine duplicate entries. 💜

--section-start=sectionname=org — pins a section in the output file to the absolute address org gives you 🎯 use it as many times as you want to pin multiple sections right there on the command line, no cap. org has to be one single hexadecimal integer — and for compat with other linkers you're allowed to drop the leading 0x that hex values usually wear. Heads up bestie: there must be no white space between sectionname, the equals sign (=), and org. Not one lil space, or it's giving broken.
--image-base=org — depends on your flavour, so listen up 👇

When you're using ELF, this is the same as -Ttext-segment, with both options effectively setting the base address of the ELF executable.

When you're using PE, the value becomes the base address of your program or dll. This is the lowest memory location that will be used when your program or dll is loaded. To reduce the need to relocate and improve performance of your dlls, each one should have a unique base address and not overlap any other dlls. Defaults are 0x400000 for executables and 0x10000000 for dlls 💅

-Tbss=org
-Tdata=org
-Ttext=org — same as --section-start, except the sectionname is locked in as ".bss", ".data" or ".text" respectively. Shortcut city ✨
-Ttext-segment=org — when you're creating an ELF executable, it sets the address of the first byte of the first segment. Important lore: when -pie is used with -Ttext-segment=org, the output executable gets marked ET_EXEC so that the address of the first byte of the text segment is guaranteed to be org at run time. Guaranteed, fr fr 🔥
-Trodata-segment=org — when creating an ELF executable or shared object for a target where the read-only data lives in its own segment separate from the executable text, this sets the address of the first byte of the read-only data segment 🎀
-Tldata-segment=org — when creating an ELF executable or shared object for x86-64 medium memory model, it sets the address of the first byte of the ldata segment. Niche but iconic 🦋
--unresolved-symbols=method — decides how to handle unresolved symbols. There are four possible values for method, and they are:
- ignore-all — do not report any unresolved symbols. Ignorance is bliss 😌
- report-all — report all unresolved symbols. This is the default.
- ignore-in-object-files — report unresolved symbols that are contained in shared libraries, but ignore them if they come from regular object files.
- ignore-in-shared-libs — report unresolved symbols that come from regular object files, but ignore them if they come from shared libraries. This one's a whole vibe when you're creating a dynamic binary and you already know that all the shared libraries it should be referencing are included on the linker's command line 🫶

The behaviour for shared libraries on their own can also be controlled by the --[no-]allow-shlib-undefined option.

Normally the linker generates an error message for each reported unresolved symbol, but the option --warn-unresolved-symbols can change this to a warning. Downgrade slay 💅

--dll-verbose
--verbose[=NUMBER] — displays the version number for ld and lists the linker emulations supported. Also displays which input files can and cannot be opened, and displays the linker script being used by the linker. If the optional NUMBER argument is > 1, plugin symbol status will also be displayed. The more you know 🌈
--version-script=version-scriptfile — tells the linker the name of a version script. Typically used when creating shared libraries to specify additional information about the version hierarchy for the library being created. This option is only fully supported on ELF platforms which support shared libraries; see VERSION. It's partially supported on PE platforms, which can use version scripts to filter symbol visibility in auto-export mode: any symbols marked local in the version script will not be exported 👀
--warn-common — warns you when a common symbol gets combined with another common symbol or with a symbol definition. Unix linkers allow this somewhat sloppy practice, but linkers on some other operating systems do not. This option lets you find potential problems from combining global symbols. Unfortunately, some C libraries use this practice, so you may get some warnings about symbols in the libraries as well as in your programs. Not the libs catching strays 😭

There are three kinds of global symbols, illustrated here by C examples:

int i = 1;

A definition, which goes in the initialized data section of the output file.

extern int i;

An undefined reference, which does not allocate space. There must be either a definition or a common symbol for the variable somewhere.

int i;

A common symbol. If there are only (one or more) common symbols for a variable, it goes in the uninitialized data area of the output file. The linker merges multiple common symbols for the same variable into a single symbol. If they're of different sizes, it picks the largest size. The linker turns a common symbol into a declaration if there's a definition of the same variable.

The --warn-common option can produce five kinds of warnings. Each warning consists of a pair of lines: the first describes the symbol just encountered, and the second describes the previous symbol encountered with the same name. One or both of the two symbols will be a common symbol.

Turning a common symbol into a reference, because there is already a definition for the symbol.

<file>(<section>): warning: common of `<symbol>'
   overridden by definition
<file>(<section>): warning: defined here

Turning a common symbol into a reference, because a later definition for the symbol is encountered. Same as the previous case, just the symbols show up in a different order.

<file>(<section>): warning: definition of `<symbol>'
   overriding common
<file>(<section>): warning: common is here

Merging a common symbol with a previous same-sized common symbol.

<file>(<section>): warning: multiple common
   of `<symbol>'
<file>(<section>): warning: previous common is here

Merging a common symbol with a previous larger common symbol.

<file>(<section>): warning: common of `<symbol>'
   overridden by larger common
<file>(<section>): warning: larger common is here

Merging a common symbol with a previous smaller common symbol. Same as the previous case, just in a different encounter order.

<file>(<section>): warning: common of `<symbol>'
   overriding smaller common
<file>(<section>): warning: smaller common is here

--warn-constructors — warns if any global constructors are used. Only useful for a few object file formats. For formats like COFF or ELF, the linker cannot detect the use of global constructors. So like… it just won't know 💀
--warn-execstack
--warn-execstack-objects
--no-warn-execstack — on ELF platforms the linker may generate warning messages if it's asked to create an output file that contains an executable stack. Three possible states, bestie:
1. Do not generate any warnings.
2. Always generate warnings, even if the executable stack is requested via the -z execstack command line option.
3. Only generate a warning if an object file requests an executable stack, but not if the -z execstack option is used.

The default state depends on how the linker was configured when it was built. --no-warn-execstack always puts the linker into the no-warnings state. --warn-execstack puts it into the warn-always state. --warn-execstack-objects puts it into the warn-for-object-files-only state.

Note: ELF format input files can specify that they need an executable stack by having a .note.GNU-stack section with the executable bit set in its section flags. They can specify that they do not need an executable stack by having the same section, but without the executable flag bit set. If an input file doesn't have a .note.GNU-stack section then the default behaviour is target specific. For some targets, the absence of such a section implies that an executable stack is required. This is often a problem for hand crafted assembler files 🙈

--error-execstack
--no-error-execstack — if the linker is going to generate a warning message about an executable stack, then --error-execstack will instead change that warning into an error. Careful though: this option does not change the linker's execstack warning generation state. Use --warn-execstack or --warn-execstack-objects to set a specific warning state. --no-error-execstack restores the default behaviour of generating warning messages 💖
--warn-multiple-gp — warns if multiple global pointer values are required in the output file. Only meaningful for certain processors, like the Alpha. Specifically: some processors put large-valued constants in a special section. A special register (the global pointer) points into the middle of this section, so constants can be loaded efficiently via a base-register relative addressing mode. Since the offset in base-register relative mode is fixed and relatively small (e.g., 16 bits), that limits the maximum size of the constant pool. So in large programs it's often necessary to use multiple global pointer values to be able to address all possible constants. This option causes a warning whenever that case occurs. Big program problems 🧚
--warn-once — only warn once for each undefined symbol, rather than once per module which refers to it. One warning, one time, we move 🦋
--warn-rwx-segments
--no-warn-rwx-segments — warns if the linker creates a loadable, non-zero sized segment that has all three of the read, write and execute permission flags set. Such a segment represents a potential security vulnerability 🚨 In addition, warnings will be generated if a thread local storage segment is created with the execute permission flag set, regardless of whether or not it has the read and/or write flags set. R W and X together is not the flex you think it is, bestie 💀

These warnings are on by default, bestie — that's the whole point ✨. You can turn them off with --no-warn-rwx-segments and turn them back on with --warn-rwx-segments. That's it, that's the toggle.

--error-rwx-segments, --no-error-rwx-segments — so if the linker is about to warn you about an executable, writeable segment, or an executable TLS segment, then --error-rwx-segments upgrades that lil warning into a full-on error 😤. And --no-error-rwx-segments puts the vibe back to default behaviour — just a warning message, no drama.

Heads up bestie 🫶 — --error-rwx-segments does not by itself switch on warnings about these segments. Those warnings are already enabled by default (if the linker was configured that way), or you turn them on yourself with the --warn-rwx-segments command line option. Don't skip the step, iykyk.

--warn-section-align — warns you if the address of an output section gets changed because of alignment. Typically the alignment comes from an input section. The address only gets changed if it wasn't explicitly specified — meaning if the SECTIONS command doesn't specify a start address for that section. So yeah, only the vibes-without-a-plan case ✨
--warn-textrel — warns if the linker adds DT_TEXTREL to a position-independent executable or shared object. lowkey scary tag, now you'll know 💀
--warn-alternate-em — warns if an object has alternate ELF machine code. Niche? Yes. Still important 🎀
--warn-unresolved-symbols — if the linker is about to report an unresolved symbol (peep the --unresolved-symbols option), it normally throws an error at you. This option makes it genuinely just warn instead. Soft launch of a problem 😭
--error-unresolved-symbols — and this one restores the linker's default behaviour of generating errors when it's reporting unresolved symbols. back to business 👑
--whole-archive — okay so for each archive mentioned on the command line after --whole-archive, it includes every object file in that archive in the link, instead of searching the archive for just the required object files. It's normally used to turn an archive file into a shared library, forcing every single object to be included in the resulting shared library. You can use this option more than once, go off 💅

Small thing but real thing: this option isn't allowed inside a --start-lib/--end-lib option pair.

Two notes when you're using this from gcc:

gcc doesn't know about this option, so you have to use -Wl,-whole-archive.
Don't forget to use -Wl,-no-whole-archive after your list of archives! Because gcc adds its own list of archives to your link and you probably don't want this flag affecting those too 😬

--link-mapless — accepts archives that lack an index aka a symbol map for all the subsequent archives referred to on the command line. If it's missing, the index gets made internally on the fly at a performance cost. And this is the default, so it's already doing this for you 🧚
*--wrap=symbol* — okay this one's iconic, pay attention 👑. Use a wrapper function for symbol. Any undefined reference to symbol gets resolved to __wrap_symbol. And any undefined reference to __real_symbol gets resolved to symbol.

This is how you provide a wrapper for a system function. Your wrapper function should be called __wrap_symbol. And if it wants to call the actual system function, it should call __real_symbol.

Here's a trivial example, literally right here:

void *
__wrap_malloc (size_t c)
{
  printf ("malloc called with %zu\n", c);
  return __real_malloc (c);
}

So if you link other code with this file using --wrap malloc, then all calls to malloc will call the function __wrap_malloc instead. And the call to __real_malloc inside __wrap_malloc will call the real malloc function. Chef's kiss, it works 🍓

You might also want to provide a __real_malloc function so that links without the --wrap option will succeed. But if you do that, do not put the definition of __real_malloc in the same file as __wrap_malloc — because if you do, the assembler may resolve the call before the linker has a chance to wrap it to malloc. And then the whole bit falls apart 😭

Another thing: only undefined references get replaced by the linker. So translation-unit-internal references to symbol are not resolved to __wrap_symbol. In the next example, the call to f inside g is not resolved to __wrap_f:

int
f (void)
{
  return 123;
}

int
g (void)
{
  return f();
}

--eh-frame-hdr, --no-eh-frame-hdr — request (--eh-frame-hdr) or suppress (--no-eh-frame-hdr) the creation of the .eh_frame_hdr section and the ELF PT_GNU_EH_FRAME segment header. Pick your fighter ✨
--no-ld-generated-unwind-info — requests creation of .eh_frame unwind info for linker generated code sections like PLT. This option is on by default if linker generated unwind info is supported. yes the name is confusing, that's just how it is 🙈
--discard-sframe — discards .sframe stack trace info from the output. It also prohibits the creation of SFrame stack trace data for linker generated code sections like PLT. This option is off by default, so it's opt-in only 🎀
--enable-new-dtags, --disable-new-dtags — okay so this linker can create the new dynamic tags in ELF. But older ELF systems may not understand them 😬. If you specify --enable-new-dtags, the new dynamic tags get created as needed and older dynamic tags get omitted. If you specify --disable-new-dtags, no new dynamic tags get created at all. By default, the new dynamic tags are not created. And note that these options are only available for ELF systems, periodt 💅
*--hash-size=number* — sets the default size of the linker's hash tables to a prime number close to number. Bumping this value up can reduce how long the linker takes to do its tasks, at the expense of increasing the linker's memory requirements. Same energy in reverse: lowering it can reduce memory requirements at the expense of speed. The default value is 4051 under normal circumstances, and 1021 if the --reduce-memory-overheads command line option is used. Numbers matter, don't forget them 🔥
*--hash-style=style* — sets the type of the linker's hash table(s). style can be sysv for the classic ELF .hash section, gnu for the new style GNU .gnu.hash section, or both for both the classic ELF .hash and the new style GNU .gnu.hash hash tables. The default depends on how the linker was configured, but for most Linux based systems it'll be both. Slay 🌈
--compress-debug-sections=none, --compress-debug-sections=zlib, --compress-debug-sections=zlib-gnu, --compress-debug-sections=zlib-gabi, --compress-debug-sections=zstd — on ELF platforms, these options control how DWARF debug sections get compressed using zlib 🦋

Let's break it down:

--compress-debug-sections=none doesn't compress DWARF debug sections at all.
--compress-debug-sections=zlib-gnu compresses them and renames them to begin with .zdebug instead of .debug.
--compress-debug-sections=zlib-gabi also compresses them, but rather than renaming, it sets the SHF_COMPRESSED flag in the sections' headers.
--compress-debug-sections=zlib is an alias for --compress-debug-sections=zlib-gabi. Same thing, shorter name ✨
--compress-debug-sections=zstd compresses DWARF debug sections using zstd.

Important note bestie 😭 — this option overrides any compression in input debug sections. So if a binary is linked with --compress-debug-sections=none, for example, then any compressed debug sections in input files will be uncompressed before they get copied into the output binary. It redoes the whole thing.

The default compression behaviour varies depending on the target involved and the configure options used to build the toolchain. You can figure out the default by examining the output from the linker's --help option. Detective work, but make it cute 🔍

--reduce-memory-overheads — this option reduces memory requirements at ld runtime, at the expense of linking speed. It was introduced to select the old O(n^2) algorithm for link map file generation rather than the new O(n) algorithm, which uses about 40% more memory for symbol storage. Trade-offs, babes ⚖️

Another effect of the switch is setting the default hash table size to 1021, which again saves memory at the cost of lengthening the linker's run time. That is not done, however, if the --hash-size switch has been used — so if you already picked your hash size, it respects that 💅

And the --reduce-memory-overheads switch may also be used to enable other tradeoffs in future versions of the linker. Future-proofed, we love to see it.

--max-cache-size=size — ld normally caches the relocation information and symbol tables of input files in memory with an *unlimited size. This option sets the maximum cache size to *size. Note — if the --no-keep-memory command line option has been used, then the linker acts as if the maximum cache size has been set to 0, ie nothing is retained. Cold. Empty. Nothing in the cache 🥲
*--build-id, --build-id=style* — requests the creation of a .note.gnu.build-id ELF note section or a .buildid COFF section. The contents of the note are unique bits identifying this linked file, like a lil fingerprint 👑

style can be:

uuid — to use 128 random bits
sha1 — to use a 160-bit SHA1 hash
md5 — to use a 128-bit MD5 hash
xx — to use a 128-bit XXHASH
0xhexstring — to use a chosen bit string specified as an even number of hexadecimal digits (the - and : characters between digit pairs are ignored)

The md5, sha1, and xx styles are computed on the normative parts of the output contents. And if style is omitted, sha1 is used.

The md5, sha1, and xx styles produce an identifier that's always the same in an identical output file, but are almost certainly unique among all nonidentical output files. It is not intended to be compared as a checksum for the file's contents — like, don't do that, that's not what it's for 🙈. A linked file may be changed later by other tools, but the build ID bit string identifying the original linked file does not change. Loyal to the end 🫶

Passing none for style disables the setting from any --build-id options earlier on the command line. Cancel that, queen 💅

--package-metadata=JSON — okay so this one asks the linker to create a .note.package ELF note section for you ✨ and the contents of that note are in JSON format, exactly as the package metadata specification says. Want the receipts? Here: https://systemd.io/ELF_PACKAGE_METADATA/ 🫶

And the JSON argument itself? It supports percent-encoding, plus these %[string] escapes (where string is the name over in HTML's Named Character References): %[comma] for ,, %[lbrace] for {, %[quot] for ", %[rbrace] for }, and %[space] for the space character 💅

Also important, bestie: if the JSON argument is missing or empty, this disables the creation of the metadata note — but only if one had been enabled by an earlier occurrence of the --package-metadata option. And if the linker has been built with libjansson, then the JSON string will be validated ✅

So, plot twist: the PE linker also supports the -shared option, which makes the output a dynamically linked library (DLL) instead of a normal executable 🎀 You should name that output "*.dll" when you use this option, fr fr.

On top of that, the linker fully supports the standard "*.def" files, which you can specify on the linker command line just like an object file — in fact, it should precede the archives it exports symbols from, to make sure those actually get linked in, just like a normal object file 👑

In addition to the options common to all targets, the PE linker supports extra command-line options that are specific to the PE target. And options that take values may be separated from their values by either a space or an equals sign — flexible, we love that 🌸

✨ PE-target options ✨

--add-stdcall-alias — if given, symbols with a stdcall suffix (@nn) will be exported as-is and also with the suffix stripped 🦋 [This option is specific to PE targeted ports of the linker]
--base-file file — use file as the name of a file in which to save the base addresses of all the relocations needed for generating DLLs with dlltool 💖 [This option is specific to PE targeted ports of the linker]
--dll — create a DLL instead of a regular executable. You may also use -shared or specify a "LIBRARY" in a given ".def" file 🎀 [This option is specific to PE targeted ports of the linker]
--enable-long-section-names
--disable-long-section-names — the PE variants of the COFF object format add an extension that permits section names longer than eight characters, which is the normal limit for COFF. By default these names are only allowed in object files, because fully-linked executable images do not carry the COFF string table required to support the longer names. As a GNU extension, you can allow their use in executable images as well — or (probably pointlessly!) disallow it in object files — by using these two options 🙈 Executable images generated with these long section names are slightly non-standard, since they carry a string table, and may generate confusing output when examined with non-GNU PE-aware tools, such as file viewers and dumpers 👀 However, GDB relies on the use of PE long section names to find Dwarf-2 debug information sections in an executable image at runtime — so if neither option is specified on the command-line, ld will enable long section names, overriding the default and technically correct behaviour, when it finds the presence of debug information while linking an executable image and not stripping symbols 🔥 [This option is specific to PE targeted ports of the linker]
--enable-stdcall-fixup
--disable-stdcall-fixup — if the link finds a symbol that it cannot resolve, it will attempt "fuzzy linking" by looking for another defined symbol that differs only in the format of the symbol name (cdecl vs stdcall) and will resolve that symbol by linking to the match 😭 For example, the undefined symbol "_foo" might be linked to the function "_foo@12", or the undefined symbol "_bar@16" might be linked to the function "_bar". When the linker does this it prints a warning, since it normally should have failed to link — but sometimes import libraries generated from third-party dlls may need this feature to be usable. If you specify --enable-stdcall-fixup, this feature is fully enabled and warnings are not printed ✨ If you specify --disable-stdcall-fixup, this feature is disabled and such mismatches are considered to be errors 💀 [This option is specific to PE targeted ports of the linker]
--leading-underscore
--no-leading-underscore — for most targets the default symbol-prefix is an underscore, and it's defined in the target's description. With this option it is possible to disable/enable the default underscore symbol-prefix 💅 [This option is specific to PE targeted ports of the linker]
--export-all-symbols — if given, all global symbols in the objects used to build a DLL will be exported by the DLL 🎉 Note that this is the default if there otherwise wouldn't be any exported symbols. When symbols are explicitly exported via DEF files or implicitly exported via function attributes, the default is to not export anything else unless this option is given.

Note that the symbols "DllMain@12", "DllEntryPoint@0", "DllMainCRTStartup@12", and "impure_ptr" will not be automatically exported 🙅‍♀️ Also, symbols imported from other DLLs will not be re-exported, nor will symbols specifying the DLL's internal layout such as those beginning with "_head_" or ending with "_iname".

In addition, no symbols from "libgcc", "libstd++", "libmingw32", or "crtX.o" will be exported. Symbols whose names begin with "__rtti_" or "__builtin_" will not be exported, to help with C++ DLLs 🧚 Finally, there is an extensive list of cygwin-private symbols that are not exported (obviously, this applies only when building DLLs for cygwin targets). These cygwin-excludes are: "_cygwin_dll_entry@12", "_cygwin_crt0_common@8", "_cygwin_noncygwin_dll_entry@12", "_fmode", "_impure_ptr", "cygwin_attach_dll", "cygwin_premain0", "cygwin_premain1", "cygwin_premain2", "cygwin_premain3", and "environ" 🌈 [This option is specific to PE targeted ports of the linker]

--exclude-symbols symbol,symbol,... — specifies a list of symbols which should not be automatically exported. The symbol names may be delimited by commas or colons 🍓 [This option is specific to PE targeted ports of the linker]
--exclude-all-symbols — specifies no symbols should be automatically exported 🙈 [This option is specific to PE targeted ports of the linker]
--file-alignment — specify the file alignment. Sections in the file will always begin at file offsets which are multiples of this number. This defaults to 512 📏 [This option is specific to PE targeted ports of the linker]
--heap reserve
--heap reserve,commit — specify the number of bytes of memory to reserve (and optionally commit) to be used as heap for this program. The default is 1MB reserved, 4K committed 💖 [This option is specific to PE targeted ports of the linker]
--kill-at — if given, the stdcall suffixes (@nn) will be stripped from symbols before they are exported ✂️ [This option is specific to PE targeted ports of the linker]
--large-address-aware — if given, the appropriate bit in the "Characteristics" field of the COFF header is set to indicate that this executable supports virtual addresses greater than 2 gigabytes 🔥 This should be used in conjunction with the /3GB or /USERVA=value megabytes switch in the "[operating systems]" section of the BOOT.INI. Otherwise, this bit has no effect. [This option is specific to the i386 PE targeted port of the linker]
--disable-large-address-aware — reverts the effect of a previous --large-address-aware option. This is useful if --large-address-aware is always set by the compiler driver (e.g. Cygwin gcc) and the executable does not support virtual addresses greater than 2 gigabytes 💀 [This option is specific to the i386 PE targeted port of the linker]
--major-image-version value — sets the major number of the "image version". Defaults to 1 ⭐ [This option is specific to PE targeted ports of the linker]
--major-os-version value — sets the major number of the "os version". Defaults to 4 ⭐ [This option is specific to PE targeted ports of the linker]
--major-subsystem-version value — sets the major number of the "subsystem version". Defaults to 4 ⭐ [This option is specific to PE targeted ports of the linker]
--minor-image-version value — sets the minor number of the "image version". Defaults to 0 ✨ [This option is specific to PE targeted ports of the linker]
--minor-os-version value — sets the minor number of the "os version". Defaults to 0 ✨ [This option is specific to PE targeted ports of the linker]
--minor-subsystem-version value — sets the minor number of the "subsystem version". Defaults to 0 ✨ [This option is specific to PE targeted ports of the linker]
--output-def file — the linker will create file, which will contain a DEF file corresponding to the DLL the linker is generating 🎀 This DEF file (which should be called "*.def") may be used to create an import library with "dlltool", or may be used as a reference to automatically or implicitly exported symbols. [This option is specific to PE targeted ports of the linker]
--enable-auto-image-base
--enable-auto-image-base= value — automatically choose the image base for DLLs, optionally starting with base value, unless one is specified using the "--image-base" argument 🦋 By using a hash generated from the dllname to create unique image bases for each DLL, in-memory collisions and relocations which can delay program execution are avoided ✨ [This option is specific to PE targeted ports of the linker]
--disable-auto-image-base — do not automatically generate a unique image base. If there is no user-specified image base ("--image-base") then use the platform default 🙅‍♀️ [This option is specific to PE targeted ports of the linker]
--dll-search-prefix string — when linking dynamically to a dll without an import library, search for "<string><basename>.dll" in preference to "lib<basename>.dll" 🔍 This behaviour allows easy distinction between DLLs built for the various "subplatforms": native, cygwin, uwin, pw, etc. For instance, cygwin DLLs typically use "--dll-search-prefix=cyg" 👑 [This option is specific to PE targeted ports of the linker]
--enable-auto-import — ngl this one does ✨sophisticated✨ linking of _symbol to __imp__symbol for DATA imports from DLLs, which means you can straight-up bypass the dllimport mechanism on the user side and reference unmangled symbol names. [This option is specific to PE targeted ports of the linker]

Quick heads up bestie: the following remarks pertain to the original implementation of the feature and are obsolete nowadays for Cygwin and MinGW targets.

Note: use of the 'auto-import' extension will cause the text section of the image file to be made writable. This does not conform to the PE-COFF format specification published by Microsoft. 😬

Note — use of the 'auto-import' extension will also cause read only data which would normally be placed into the .rdata section to be placed into the .data section instead. This is in order to work around a problem with consts that is described here: http://www.cygwin.com/ml/cygwin/2004-09/msg01101.html

Using 'auto-import' generally will 'just work' — but sometimes you may see this message:

"variable '<var>' can't be auto-imported. Please read the
documentation for ld's "--enable-auto-import" for details."

This message occurs when some (sub)expression accesses an address ultimately given by the sum of two constants (Win32 import tables only allow one). Instances where this may occur include accesses to member fields of struct variables imported from a DLL, as well as using a constant index into an array variable imported from a DLL. Any multiword variable (arrays, structs, long long, etc) may trigger this error condition. However, regardless of the exact data type of the offending exported variable, ld will always detect it, issue the warning, and exit. 💀

There are several ways to address this difficulty, regardless of the data type of the exported variable:

One way is to use --enable-runtime-pseudo-reloc switch. This leaves the task of adjusting references in your client code for runtime environment, so this method works only when runtime environment supports this feature.

A second solution is to force one of the 'constants' to be a variable — that is, unknown and un-optimizable at compile time. For arrays, there are two possibilities: a) make the indexee (the array's address) a variable, or b) make the 'constant' index a variable. Thus:

        extern type extern_array[];
        extern_array[1] -->
           { volatile type *t=extern_array; t[1] }

        extern type extern_array[];
        extern_array[1] -->
           { volatile int t=1; extern_array[t] }

For structs (and most other multiword data types) the only option is to make the struct itself (or the long long, or the ...) variable:

        extern struct s extern_struct;
        extern_struct.field -->
           { volatile struct s *t=&extern_struct; t->field }

        extern long long extern_ll;
        extern_ll -->
          { volatile long long * local_ll=&extern_ll; *local_ll }

A third method of dealing with this difficulty is to abandon 'auto-import' for the offending symbol and mark it with "__declspec(dllimport)". However, in practice that requires using compile-time #defines to indicate whether you are building a DLL, building client code that will link to the DLL, or merely building/linking to a static library. In making the choice between the various methods of resolving the 'direct address with constant offset' problem, you should consider typical real-world usage:

Original:

        --foo.h
        extern int arr[];
        --foo.c
        #include "foo.h"
        void main(int argc, char **argv){
          printf("%d\n",arr[1]);
        }

Solution 1:

        --foo.h
        extern int arr[];
        --foo.c
        #include "foo.h"
        void main(int argc, char **argv){
          /* This workaround is for win32 and cygwin; do not "optimize" */
          volatile int *parr = arr;
          printf("%d\n",parr[1]);
        }

Solution 2:

        --foo.h
        /* Note: auto-export is assumed (no __declspec(dllexport)) */
        #if (defined(_WIN32) || defined(__CYGWIN__)) && \
          !(defined(FOO_BUILD_DLL) || defined(FOO_STATIC))
        #define FOO_IMPORT __declspec(dllimport)
        #else
        #define FOO_IMPORT
        #endif
        extern FOO_IMPORT int arr[];
        --foo.c
        #include "foo.h"
        void main(int argc, char **argv){
          printf("%d\n",arr[1]);
        }

A fourth way to avoid this problem is to re-code your library to use a functional interface rather than a data interface for the offending variables (e.g. set_foo() and get_foo() accessor functions). 🫶

--disable-auto-import — yeah, don't attempt the sophisticated linking of _symbol to __imp__symbol for DATA imports from DLLs. [This option is specific to PE targeted ports of the linker]
--enable-runtime-pseudo-reloc — if your code contains expressions described in the --enable-auto-import section (that is, DATA imports from DLL with non-zero offset), this switch will create a vector of 'runtime pseudo relocations' which can be used by runtime environment to adjust references to such data in your client code. [This option is specific to PE targeted ports of the linker]
--disable-runtime-pseudo-reloc — nope, do not create pseudo relocations for non-zero offset DATA imports from DLLs. [This option is specific to PE targeted ports of the linker]
--enable-extra-pe-debug — show additional debug info related to auto-import symbol thunking. [This option is specific to PE targeted ports of the linker]
--section-alignment — sets the section alignment. Sections in memory will always begin at addresses which are a multiple of this number. Defaults to 0x1000. [This option is specific to PE targeted ports of the linker]
--stack reserve
--stack reserve,commit — specify the number of bytes of memory to reserve (and optionally commit) to be used as stack for this program. The default is 2MB reserved, 4K committed. [This option is specific to PE targeted ports of the linker]
--subsystem which
--subsystem which:major
--subsystem which:major.minor — specifies the subsystem under which your program will execute. The legal values for which are "native", "windows", "console", "posix", and "xbox". You may optionally set the subsystem version also. Numeric values are also accepted for which. [This option is specific to PE targeted ports of the linker]

The following options set flags in the "DllCharacteristics" field of the PE file header: [These options are specific to PE targeted ports of the linker]

--high-entropy-va
--disable-high-entropy-va — image is compatible with 64-bit address space layout randomization (ASLR). This option is enabled by default for 64-bit PE images in MinGW targets.

This option also implies --dynamicbase and --enable-reloc-section. [This options is specific to 64-bit PE targeted ports of the linker]

--dynamicbase
--disable-dynamicbase — the image base address may be relocated using address space layout randomization (ASLR). This feature was introduced with MS Windows Vista. This option is enabled by default for MinGW targets but can be disabled via the --disable-dynamicbase option. This option also implies --enable-reloc-section.
--forceinteg
--disable-forceinteg — code integrity checks are enforced. This option is disabled by default.
--nxcompat
--disable-nxcompat — the image is compatible with the Data Execution Prevention. This feature was introduced with MS Windows XP SP2. The option is enabled by default for MinGW targets.
--no-isolation
--disable-no-isolation — although the image understands isolation, do not isolate the image. This option is disabled by default.
--no-seh
--disable-no-seh — the image does not use SEH. No SE handler may be called from this image. This option is disabled by default.
--no-bind
--disable-no-bind — do not bind this image. This option is disabled by default.
--wdmdriver
--disable-wdmdriver — the driver uses the MS Windows Driver Model. This option is disabled by default.
--tsaware
--disable-tsaware — the image is Terminal Server aware. This option is disabled by default. 🦋
--insert-timestamp
--no-insert-timestamp — insert a real timestamp into the image. This is the default behaviour as it matches legacy code and it means that the image will work with other, proprietary tools. The problem with this default is that it will result in slightly different images being produced each time the same sources are linked. The option --no-insert-timestamp can be used to insert a zero value for the timestamp, this ensuring that binaries produced from identical sources will compare identically. ⭐

If --insert-timestamp is active then the time inserted is either the time that the linking takes place or, if the "SOURCE_DATE_EPOCH" environment variable is defined, the number of seconds since Unix epoch as specified by that variable.

--enable-reloc-section
--disable-reloc-section — create the base relocation table, which is necessary if the image is loaded at a different image base than specified in the PE header. This option is enabled by default.

<h2>🧚 the DSBT era (C6X uClinux girlies rise) 🧚</h2>

The C6X uClinux target uses a binary format called DSBT to support shared libraries. Each shared library in the system needs to have a unique index; all executables use an index of 0.

--dsbt-size size — this option sets the number of entries in the DSBT of the current executable or shared library to size. The default is to create a table with 64 entries.
--dsbt-index index — this option sets the DSBT index of the current executable or shared library to index. The default is 0, which is appropriate for generating executables. If a shared library is generated with a DSBT index of 0, the "R_C6000_DSBT_INDEX" relocs are copied into the output file. 💅
--no-merge-exidx-entries — this switch disables the merging of adjacent exidx entries in frame unwind info. no cap 🫶
--branch-stub — this turns on linker branch relaxation by inserting branch stub sections when needed to extend the range of branches. It’s usually not required because C-SKY supports branch and call instructions that can access the full memory range, and branch relaxation is normally handled by the compiler or assembler. 💅
--stub-group-size=N — this gives you finer control of linker branch stub creation. It sets the maximum size of a group of input sections that can be handled by one stub section. A negative value of N locates stub sections after their branches, while a positive value allows stub sections to appear either before or after the branches. Values of 1 or -1 mean the linker should choose suitable defaults. ✨

The 68HC11 and 68HC12 linkers support specific options to control the memory bank switching mapping and trampoline code generation. 🎀

--no-trampoline — this disables the generation of trampoline. By default a trampoline is generated for each far function which is called using a jsr instruction (this happens when a pointer to a far function is taken). 🙈
--bank-window name — this tells the linker the name of the memory region in the MEMORY specification that describes the memory bank window. That region’s definition is then used by the linker to compute paging and addresses within the memory window. 🌸

The following options are supported to control handling of GOT generation when linking for 68K targets. 💜

--got=type — this tells the linker which GOT generation scheme to use. type should be one of single, negative, multigot or target. For more information refer to the Info entry for ld. 🔥

The following options are supported to control microMIPS instruction generation and branch relocation checks for ISA mode transitions when linking for MIPS targets. 🦋

--insn32, --no-insn32 — these control the choice of microMIPS instructions used in code generated by the linker, like the code in the PLT or lazy binding stubs, or in relaxation. If --insn32 is used, then the linker only uses 32-bit instruction encodings. By default, or if --no-insn32 is used, all instruction encodings are used, including 16-bit ones where possible. 👑
--ignore-branch-isa, --no-ignore-branch-isa — these control branch relocation checks for invalid ISA mode transitions. If --ignore-branch-isa is used, then the linker accepts any branch relocations, and any ISA mode transition required is lost in relocation calculation — except for some cases of BAL instructions which meet relaxation conditions and are converted to equivalent JALX instructions as the associated relocation is calculated. By default, or if --no-ignore-branch-isa is used, a check is made causing the loss of an ISA mode transition to produce an error. 😭
--compact-branches, --no-compact-branches — these control the generation of compact instructions by the linker in the PLT entries for MIPS R6. ⭐

For the pdp11-aout target, three variants of the output format can be produced as selected by the following options. The default variant for pdp11-aout is the --omagic option, whereas for other targets --nmagic is the default. The --imagic option is defined only for the pdp11-aout target, while the others are described here as they apply to the pdp11-aout target. 🧚

-N, --omagic — mark the output as OMAGIC (0407) in the a.out header to indicate that the text segment is not to be write-protected and shared. Since the text and data sections are both readable and writable, the data section is allocated immediately contiguous after the text segment. This is the oldest format for PDP11 executable programs and is the default for ld on PDP11 Unix systems from the beginning through 2.11BSD. 🌈
-n, --nmagic — mark the output as NMAGIC (0410) in the a.out header to indicate that when the output file is executed, the text portion will be read-only and shareable among all processes executing the same file. This involves moving the data areas up to the first possible 8K byte page boundary following the end of the text. This option creates a pure executable format. ✨
-z, --imagic — mark the output as IMAGIC (0411) in the a.out header to indicate that when the output file is executed, the program text and data areas will be loaded into separate address spaces using the split instruction and data space feature of the memory management unit in larger models of the PDP11. This doubles the address space available to the program. The text segment is again pure, write-protected, and shareable. The only difference in the output format between this option and the others, besides the magic number, is that both the text and data sections start at location 0. The -z option selected this format in 2.11BSD. This option creates a separate executable format. 💖
--no-omagic — equivalent to --nmagic for pdp11-aout. 🎀

🌱 ENVIRONMENT 🌱

You can change the behaviour of ld with the environment variables GNUTARGET, LDEMULATION and COLLECT_NO_DEMANGLE. 🫶

GNUTARGET determines the input-file object format if you don’t use -b (or its synonym --format). Its value should be one of the BFD names for an input format. If there is no GNUTARGET in the environment, ld uses the natural format of the target. If GNUTARGET is set to default then BFD attempts to discover the input format by examining binary input files; this method often succeeds, but there are potential ambiguities, since there is no method of ensuring that the magic number used to specify object-file formats is unique. However, the configuration procedure for BFD on each system places the conventional format for that system first in the search-list, so ambiguities are resolved in favor of convention. 💅

LDEMULATION determines the default emulation if you don’t use the -m option. The emulation can affect various aspects of linker behaviour, particularly the default linker script. You can list the available emulations with the --verbose or -V options. If the -m option is not used, and the LDEMULATION environment variable is not defined, the default emulation depends upon how the linker was configured. 👑

Normally, the linker will default to demangling symbols. However, if COLLECT_NO_DEMANGLE is set in the environment, then it will default to not demangling symbols. This environment variable is used in a similar fashion by the gcc linker wrapper program. The default may be overridden by the --demangle and --no-demangle options. 🦋

If the PE/COFF specific --insert-timestamp is active and the SOURCE_DATE_EPOCH environment variable is defined, then the timestamp value in this variable will be inserted into the COFF header instead of the current time. ⭐

If the LD_STATS environment variable is defined then linker resource use information will be recorded, just as if the --stats option had been used. If the LD_STATS variable has a string value then this will be used as the name of a file into which the information should be stored. Otherwise the information will be sent to the standard output stream. 🌸

👀 SEE ALSO 👀

ar(1), nm(1), objcopy(1), objdump(1), readelf(1) and the Info entries for binutils and ld. 💖

📜 COPYRIGHT 📜

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License”. 🌈

That’s the whole page, bestie — this one comes from binutils-2.47, dated 2026-07-26 💖🎀✨

📦 where this page comes from

arch rolling: loongarch64-linux-gnu-binutils 2.47-1 · GPL-2.0-or-later AND GPL-3.0-or-later AND LGPL-2.0-or-later AND LGPL-3.0-or-later AND GFDL-1.3-or-later AND FSFAP
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on 2026-11-04: a language model's rewrite of the original, under its terms