LD(1)

📦

version 2.44 · 3 versions

✨ LD(1) ✨

the GNU linker — aka the GNU Development Tools girlie of the manual pages, section 1, bestie 💅

NAME 💖

ld — the GNU linker. that's it, that's the whole name, she's simple like that 🎀

SYNOPSIS ✨

ld [options] objfile ...

DESCRIPTION 🦋

okay so. ld takes a whole bunch of object and archive files, relocates their data, and ties up symbol references. no cap. usually the very last step in compiling a program is running ld — she's the finale, the last one on stage, the closing number 👑

ld accepts Linker Command Language files written in a superset of AT&T's Link Editor Command Language syntax, which is how you get explicit and total control over the linking process. total control. main character energy fr fr.

heads up bestie: this man page does not describe the command language. for full details on the command language and on other aspects of the GNU linker, go look at the ld entry in info. iykyk 🌸

this version of ld uses the general purpose BFD libraries to operate on object files, which is the whole reason she can read, combine, and write object files in so many different formats — for example, COFF or a.out. different formats can even be linked together to produce any available kind of object file. versatile queen 🌈

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 keeps going, which lets you identify other errors — or, in some cases, to get an output file in spite of the error. she's not a quitter 💀

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. so many. buckle up 🎀

OPTIONS 🌸

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. noted. don't forget 📝

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. that one's a hard no 🙈

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.

(okay technically the message is just No input files — no output, no vibes, nothing 💀)

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. two very different things, bestie, don't mix them up 💅

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. sneaky little detail, love that for us 🔥

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. cute 💖

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

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. ngl that's a polite fallback 🫶

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. it's giving inception ✨

`-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. go off 💅

`--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. ELF girlies only 💜

`-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.) handy 👀

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. so she'll go hunting 🕵️‍♀️

`-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. same vibe, different name ✨

`--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. position matters bestie, she's picky 💅

`--disable-linker-version` 💀

disables the LINKER_VERSION linker script directive, so that it does not insert a version string. this is the default. the chill one, the go-to, the no-effort queen 🫶

--enable-non-contiguous-regions — bestie this one is SO chill, it literally refuses to throw a fit when an input section doesn't fit into a matching output section. Instead of erroring out immediately, the linker goes shopping: it tries to allocate that input section into subsequent matching output sections, and only actually generates an error if no output section is big enough. It's giving "there's always another option" energy. Super useful when you've got several non-contiguous memory regions kicking around and your input section doesn't need any particular one. The order in which input sections get evaluated does not change, like so:

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
}

and with these input sections:

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

the result is .data.1 affected to mem1, and .data.2 and .data.3 affected to mem2 — even though .data.3 would have fit in mem3. Yes, the linker really said "nope, we're going in order, I don't make the rules."

Heads up queen: this option is incompatible with INSERT statements, because it changes the way input sections are mapped to output sections. Not compatible. At all. 💀

--enable-non-contiguous-regions-warnings — turns on warnings for when --enable-non-contiguous-regions allows possibly unexpected matches in section mapping. Why do you care? Because those sneaky matches could potentially lead to a section being silently discarded instead of just failing loudly because it doesn't fit any output region. Silent discards are the villain of this story, so this flag snitches. 🚨
-e entry —
--entry=entry — bestie, this says: use entry as the explicit symbol for beginning execution of your program, instead of the default entry point. And if there's no symbol named entry? The linker will try to parse entry as a number and use that as the entry address. That number is interpreted in base 10, but you may use a leading 0x for base 16, or a leading 0 for base 8. Cute, right? 🎀
--exclude-libs lib,lib,... — gives you a list of archive libraries whose symbols should not be automatically exported. The library names may be delimited by commas or colons. If you say --exclude-libs ALL, you're excluding symbols in all archive libraries from automatic export. Iconic, bold, sweeping.

This option is available only for the i386 PE targeted port of the linker and for ELF targeted ports. For i386 PE, 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,... — a list of object files or archive members whose symbols should not be automatically exported, but which should still be copied wholesale into the import library being generated during the link. The module names may be delimited by commas or colons, and they 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 you list must include and match precisely any path used to specify the input file on the linker's command-line. Exact match only, no vibes-based guessing. 🙈

This option is available only for the i386 PE targeted port of the linker. Symbols explicitly listed in a .def file are still exported, regardless of this option.

-E
--export-dynamic
--no-export-dynamic — okay so when you're 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. And what is the dynamic symbol table? It's the set of symbols which are visible from dynamic objects at run time. It's the VIP list, basically. 🌟

If you don't use either of these options (or you use --no-export-dynamic 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. Small list. Exclusive list.

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. (Yes, "probably" — that's the original's word, not mine.)

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. So if you're not on one of those, it's just ✨decorative✨.
--export-dynamic-symbol-list=file — specifies 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, this sets 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.

So 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. And get this — 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. Imagine shipping a whole override and the file isn't even there. Main character behavior. 👑

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. Curated. ✨

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. Ignored. Not even looked at.

-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. The goodbye ritual. 🦋
-g — Ignored. Provided for compatibility with other tools. That's it. That's the whole thing. It's giving "I'm here so nothing breaks." 💅
-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. So the name inside wins over the name on the file. It's the government name vs. the stage name. 🎤
-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. The hello ritual. 🌸
-l namespec
--library=namespec — adds 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. One pass, bestie. It's not coming back for you. 😭

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. As many times as you want. Go off.

This type of archive searching is standard for Unix linkers. However, if you are using ld on AIX, note that it is different from the behaviour of the AIX linker. Different vibes over there entirely.

-L searchdir, --library-path=searchdir — bestie, this one adds the path searchdir to the list of paths that ld will go looking through for archive libraries and ld control scripts. You can drop this option as many times as you want 💖 The directories get searched in the order you typed them on the command line, and anything you specify on the command line gets searched before the default directories.

Also super important: every single -L option applies to all the -l options, no matter what order everything shows up in. But -L options do not affect how ld searches for a linker script unless the -T option is specified. iykyk.

If searchdir starts with = or $SYSROOT, then that prefix gets swapped out for the sysroot prefix — the one controlled by the --sysroot option, or specified back when the linker was configured.

The default set of paths that get searched (when you didn't say -L at all) depends on which emulation mode ld is using, and in some cases also on how it was configured. Very much a "depends on your setup" situation 🦋

You can also specify the paths in a link script with the "SEARCH_DIR" command. Directories specified that way are searched at the point in which the linker script appears in the command line.

-m emulation — emulate the emulation linker. You can list all the available emulations with the --verbose or -V options, go peek 👀

If the -m option is not used, the emulation is taken from the "LDEMULATION" environment variable, if that is defined.

Otherwise, the default emulation depends upon how the linker was configured.

--remap-inputs=pattern=filename, --remap-inputs-file=file — okay so these two are the glow-up options ✨ They let you change the names of input files before the linker even attempts to open them. Like, --remap-inputs=foo.o=bar.o will cause any attempt to load a file called foo.o to instead try to load a file called bar.o. Wildcard patterns are permitted in the first filename, so --remap-inputs=foo*.o=bar.o will rename any input file that matches foo*.o to bar.o. So versatile 💅

An alternative form of the option, --remap-inputs-file=filename, lets the remappings be read from a file. Each line in the file can contain a single remapping. Blank lines are ignored. Anything from a hash character (#) to the end of a line is considered to be a comment and is also ignored. The mapping pattern can be separated from the filename by whitespace or an equals (=) character.

The options can be specified multiple times. Their contents accumulate. The remappings will be processed in the order in which they occur on the command line, and if they come from a file, in the order in which they occur in the file. If a match is made, no further checking for that filename will be performed.

If the replacement filename is /dev/null or just NUL then the remapping will actually cause the input file to be ignored. This can be a convenient way to experiment with removing input files from a complicated build environment. Honestly kind of iconic for debugging 🧚

Note that this option is position dependent and only affects filenames that come after it on the command line. So:

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

Will have no effect 😭 whereas:

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

Will rename the input file foo.o to bar.o. Order matters, bestie, always.

Note — these options also affect files referenced by INPUT statements in linker scripts. But since linker scripts are 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 then any mappings that match will be reported, although again the verbose option needs to be enabled on the command line before the remaped filenames appear.

If the -Map or --print-map options are enabled then the remapping list will be included in the map output.

-M, --print-map — prints a link map to the standard output. A link map gives you the tea ☕ about the link, including the following:
- 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 which caused the archive member to be brought in.
- The values assigned to symbols.

Note — symbols whose values are computed by an expression which involves a reference to a previous value of the same symbol may not have correct result displayed in the link map. This is because the linker discards intermediate results and only retains the final value of an expression. Under such circumstances the linker will display the final value enclosed by square brackets. Thus 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 information 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 are 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 will have the text (local) printed before their name, and will be listed after all of the global symbols in a given section. Temporary local symbols (typically those that start with .L) will not be included in the output. Disabled by default 🙈
-n, --nmagic — turn off page alignment of sections, and disable linking against shared libraries. If the output format supports Unix style magic numbers, mark the output as "NMAGIC".
-N, --omagic — set the text and data sections to be readable and writable. Also, do not 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. So like, it works but Microsoft said no 💀

--no-omagic — this option negates most of the effects of the -N option. 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 this.

-o output, --output=output — use output as the name for the program produced by ld; if this option is not specified, 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 to write to it. It will do this even if it turns out that the link cannot be completed due to errors. 😭

Note — the linker will check to make sure that the output file name does not match the name of any of the input files, but that is all. In particular it will not complain if the output file might overwrite a source file or some other important file. Therefore in build systems it is recommended to use the -o option as the last option on the linker command line. For example consider:

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

If the EXE variable is not 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 of the linker command will generate an error message and not delete anything. Protect your files, bestie, put -o last 🫶

--dependency-file=depfile — write 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 is 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 values 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 is no difference in the linker's behaviour for different non-zero values of this option. Again this may change with future releases. It's giving "watch this space" ⭐
-plugin name — involve a plugin in the linking process. The name parameter is the absolute filename of the plugin. Usually this parameter is automatically added by the compiler, when using link time optimization, but users can also add their own plugins if they so wish. Custom plugins? Main character energy 👑

Okay so tiny little heads-up before we keep going — the place where the compiler-originated plugins live is not the same place where ar, nm and ranlib go hunting for their plugins. So if you want those commands to actually use a compiler-based plugin, you gotta copy it into the ${libdir}/bfd-plugins directory first. And good news bestie: all gcc-based linker plugins are backward compatible, so literally just copy in the newest one and you're done. ✨

--push-state — saves the current state of all the flags that govern input file handling, so you can bring them all back later with one matching --pop-state. It's giving "save point in a video game" 💾

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

One of the main targets for this is pkg-config specs. When you use it with the --libs option, it lists all possibly needed libraries and then they get linked in all the time. Like, girl, that's not it. It's way better to return something like this instead:

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

--pop-state — undoes what --push-state did, restoring the previous values of the flags governing input file handling. The un-save. The rewind. 🔄
-q, --emit-relocs — leaves relocation sections and their contents in fully linked executables. Post-link analysis and optimization tools may need this info so they can correctly modify executables. The tradeoff? Bigger executables. No cap.

This option is currently only supported on ELF platforms. 🐧

--force-dynamic — forces the output file to have dynamic sections. This one is specific to VxWorks targets.
-r, --relocatable — generates relocatable output, i.e. an output file that can itself serve as input to ld later. This is often called partial linking. As a 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 heads up: when linking C++ programs, this option will not resolve references to constructors — for that, use -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 that require link-time optimization (LTO) and contents that don't require LTO, a .gnu_object_only section will be created to hold a relocatable object file, as if -r were applied to all relocatable inputs that don't require LTO. And when processing a relocatable input with a .gnu_object_only section, the linker will extract that .gnu_object_only section as a separate input.

Note that 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. 😭

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 may use this option more than once. 🫶

For compatibility with other ELF linkers: if -R is followed by a directory name rather than a file name, it gets treated as the -rpath option. Sneaky little plot twist.

--rosegment, --no-rosegment — attempts to ensure that only a single read-only, non-code segment is created. Only useful when used together 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 lowkey misleading, but they were chosen so the linker stays compatible with the LLD and GOLD linkers. It's giving "don't blame us, blame the ecosystem" 🙈

These options are only supported by ELF targets.

-s, --strip-all — omits all symbol information from the output file. Gone. Deleted. Not invited. 💅
-S, --strip-debug — omits debugger symbol information from the output file (but not all symbols). So like, the debug crumbs go but the symbols stay. ✨
--strip-discarded, --no-strip-discarded — omit (or do not omit) global symbols defined in discarded sections. Enabled by default.
-plugin-save-temps — stores the plugin "temporary" intermediate files permanently. They're not temps anymore bestie, they live here now 🏡
-t, --trace — prints the names of the input files as ld processes them. If -t is given twice, then members within archives are also printed. The -t output is super 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 (rather than adding to it), unless the script contains "INSERT", so 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, babes.

Multiple -T options will accumulate if they are augmenting the current script — otherwise the last, non-augmenting, -T option will be used.

There are other ways of specifying linker scripts. See

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

This option is similar to the --script option, except that processing of the script is delayed until after the rest of the command line has been processed. That way, options placed after the --default-script option on the command line can affect the behaviour of the linker script — which is important when the linker command line can't be directly controlled by the user (like, say, because the command line is being constructed by another tool such as 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 option to force additional modules into the link, and it's an error for the symbol to remain undefined, then use the --require-defined option instead. Read the room, use the right tool 🎀

--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. This option 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 in turn serve as input to ld. For other binaries though, -Ur is similar to -r but it also resolves references to constructors and destructors.

For those 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. So use -Ur only for the last partial link, and -r for all 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 the following values:

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

The default if --orphan-handling isn't given is "place".

--unique[=SECTION] — creates a separate output section for every input section matching SECTION, or if the optional wildcard SECTION argument is missing, for every orphan input section. (An orphan section, once again, is one not specifically mentioned in a linker script.) You may use this option multiple times on the command line — it prevents the normal merging of input sections with the same name, overriding output section assignments in a linker script. No merging, no blending, everyone gets their own room 🚪
-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. Bye bestie 🫡
-X, --discard-locals — deletes all temporary local symbols. These symbols start with system-specific local label prefixes — typically .L for ELF systems, or L for traditional a.out systems. 🍓
-y symbol, --trace-symbol=symbol — prints the name of each linked file in which symbol appears. This option may be given any number of times. On many systems it's necessary to prepend an underscore.

This option is genuinely iconic when you've got an undefined symbol in your link and you have no clue where the reference is coming from. Detective mode: activated 🔍

-Y path — adds path to the default library search path. This option exists for Solaris compatibility. 🌸
-z keyword — the recognized keywords are:
call-nop=prefix-addr, call-nop=suffix-nop, call-nop=prefix-byte, call-nop=suffix-byte — okay so this is all about the 1-byte NOP padding when the linker transforms an indirect call to a locally defined function, foo, via its GOT slot. bestie, each flavor gives you a different byte:
- 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. 💅
cet-report=none, cet-report=warning, cet-report=error — so like this controls how you wanna report 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 is the default and means the linker just doesn't report missing properties in input files. cet-report=warning makes it issue a warning for missing properties in input files. cet-report=error makes it 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 — slay! combreloc combines multiple dynamic relocation sections and sorts them to improve dynamic symbol lookup caching. Do not do this if nocombreloc. 💖
common, nocommon — common generates common symbols with STT_COMMON type during a relocatable link. Use STT_OBJECT type if nocommon. periodt ✨
common-page-size=value — Set the page size most commonly used to value. Memory image layout will be optimized to minimize memory pages if the system is using pages of this size. lowkey important 🦋
defs — Report unresolved symbol references from regular object files. This is done even if the linker is creating a non-symbolic shared library. This option is the inverse of -z undefs. iykyk 👑
dynamic-undefined-weak, nodynamic-undefined-weak — Make undefined weak symbols dynamic when building a dynamic object, if they are 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. Not all targets support these options. 😭
execstack — Marks the object as requiring executable stack. vibe check: it's giving security implications 🫶
global — This option is only meaningful when building a shared object. It makes the symbols defined by this shared object available for symbol resolution of subsequently loaded libraries. main character energy 🌟
globalaudit — This option is only meaningful when building a dynamic executable. This option 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. no cap 🔥
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 .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 .note.gnu.property section to indicate that 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 .note.gnu.property section. obsessed 💖
initfirst — This option is 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. iconic ✨
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. the way that works 😌
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). fr fr 🫶
lam-u48 — Generate GNU_PROPERTY_X86_FEATURE_1_LAM_U48 in .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 .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 input .note.gnu.property section. lam-u48-report=none, which is the default, will make the linker not report missing properties in input files. lam-u48-report=warning will make the linker issue a warning for missing properties in input files. lam-u48-report=error will make 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 input .note.gnu.property section. lam-u57-report=none, which is the default, will make the linker not report missing properties in input files. lam-u57-report=warning will make the linker issue a warning for missing properties in input files. lam-u57-report=error will make 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 input .note.gnu.property section. lam-report=none, which is the default, will make the linker not report missing properties in input files. lam-report=warning will make the linker issue a warning for missing properties in input files. lam-report=error will make 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 called (lazy binding), rather than at load time. Lazy binding is the default. periodt 💅
loadfltr — Specify that the object's filters be processed immediately at runtime. it's giving instant gratification ✨
max-page-size=value — Set the maximum memory page size supported to value. simple as that 🦋
mark-plt, nomark-plt — Mark PLT entries with dynamic tags, DT_X86_64_PLT, DT_X86_64_PLTSZ and DT_X86_64_PLTENT. 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. no gatekeeping 👑
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. not like other girls 💅
nodelete — Specify that the object shouldn't be unloaded at runtime. it stays ✨
nodlopen — Specify that the object is not available to dlopen. sorry bestie 🫶
nodump — Specify that the object can not be dumped by dldump. no dump for you 💀
noexecstack — Marks the object as not requiring executable stack. good vibes only 🌸
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. 💜
noreloc-overflow — Disable relocation overflow check. This can be used to disable relocation overflow check if there will be no dynamic relocation overflow at run-time. Supported for x86_64. 🔥
memory-seal, nomemory-seal — Instruct the executable or shared library that the all PT_LOAD segments should be sealed to avoid further manipulation (such as changing the protection flags, the segment size, or remove the mapping). This is a security hardening that requires system support. This generates GNU_PROPERTY_MEMORY_SEAL in .note.gnu.property section. slay security queen 👑
now — when you're making an executable or a shared library, slap a mark on it that tells the dynamic linker "bestie, resolve ALL the symbols the second the program starts, or the second the shared library gets loaded by dlopen" — instead of doing the lazy thing and waiting until a function is literally first called. ✨
- origin — says that the object needs $ORIGIN handling in paths.
- pack-relative-relocs, nopack-relative-relocs — generates compact relative relocation in position-independent executable and shared library. It adds DT_RELR, DT_RELRSZ and DT_RELRENT entries to the dynamic section. It is ignored when building position-dependent executable and 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. 🎀
- relro, 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 supported. Heads up though: specifying common-page-size smaller than the system page size will render this protection ineffective 😭. Don't create an ELF PT_GNU_RELRO segment if norelro.
- report-relative-reloc — reports dynamic relative relocations generated by the linker. Supported for Linux/i386 and Linux/x86_64.
- sectionheader, nosectionheader — generate section header. Don't generate section header if nosectionheader is used. sectionheader is the default. 💅
- separate-code, 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. Don't create separate code PT_LOAD segment if noseparate-code is used.
- shstk — generates GNU_PROPERTY_X86_FEATURE_1_SHSTK in .note.gnu.property section to indicate compatibility with Intel Shadow Stack. Supported for Linux/i386 and Linux/x86_64. 🛡️
- stack-size=value — specify a stack size for an ELF PT_GNU_STACK segment. Specifying zero will override any default non-zero sized PT_GNU_STACK segment creation.
- start-stop-gc, nostart-stop-gc — okay so 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. -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.
- start-stop-visibility=value — specify 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. However, 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. 👑
- text, notext, textoff — report an error if DT_TEXTREL is set, i.e., if the position-independent or shared object has dynamic relocations in read-only sections. Don't report an error if notext or textoff.
- 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.
- unique-symbol, nounique-symbol — avoid duplicated local symbol names in the symbol string table. Append "."number"" to duplicated local symbol names if unique-symbol is used. nounique-symbol is the default.
- x86-64-baseline, x86-64-v2, x86-64-v3, x86-64-v4 — specify the x86-64 ISA level needed in .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. ⭐
- isa-level-report=none, isa-level-report=all, isa-level-report=needed, isa-level-report=used — specify 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.
- Other keywords are ignored for Solaris compatibility.

-( archives -), --start-group archives --end-group — the 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 will all be searched repeatedly until all possible references are resolved. 🌀

Using this option has a significant performance cost. It is best to use it only when there are unavoidable circular references between two or more archives.

--accept-unknown-input-arch, --no-accept-unknown-input-arch — tells the linker to accept input files whose architecture cannot be recognised. The assumption is that the user knows what they are 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, and so the --accept-unknown-input-arch option has been added to restore the old behaviour.
--as-needed, --no-as-needed — this option affects ELF DT_NEEDED tags for dynamic libraries mentioned on the command line after the --as-needed option. Normally the linker will add a DT_NEEDED tag for each dynamic library mentioned on the command line, regardless of whether the library is actually needed or not. --as-needed causes a DT_NEEDED tag to only be emitted 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 is not found in the DT_NEEDED lists of other needed libraries, a non-weak undefined symbol reference from another needed dynamic library. Object files or libraries appearing on the command line after the library in question do not affect whether the library is seen as needed. This is similar to the rules for extraction of object files from archives. --no-as-needed restores the default behaviour.

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 options have been deprecated 💀 because of the similarity of their names to the --as-needed and --no-as-needed options. They have been replaced by --copy-dt-needed-entries and --no-copy-dt-needed-entries.
-assert keyword — this option is ignored for SunOS compatibility.
-Bdynamic, -dy, -call_shared — link against dynamic libraries. This is only meaningful on platforms for which shared libraries are supported. This option is normally the default on such platforms. The different variants of this option 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. ✨
-Bgroup — set the DF_1_GROUP flag in the DT_FLAGS_1 entry in the dynamic section. This causes the runtime linker to handle lookups in this object and its dependencies to be performed only inside the group. --unresolved-symbols=report-all is implied. This option is only meaningful on ELF platforms which support shared libraries.
-Bstatic, -dn, -non_shared, -static — do not link against shared libraries. This is only meaningful on platforms for which shared libraries are supported. The different variants of this option 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. This option can be used with -shared. Doing so means that 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. 🫶
-Bsymbolic — when creating a shared library, bind references to global symbols to the definition within the shared library, if any. Normally, it is possible for a program linked against a shared library to override the definition within the shared library. This option is only meaningful on ELF platforms which support shared libraries.
-Bsymbolic-functions — bestie, when you're making a shared library, this one binds every reference to a global function symbol straight to its definition inside that shared library (if there even is one, ok). Heads up: it only actually means anything on ELF platforms that support shared libraries. ✨
-Bno-symbolic — the undo button 💅 this one cancels out any -Bsymbolic and -Bsymbolic-functions you said earlier. not me rewriting history, it's literally the point.
--dynamic-list=dynamic-list-file — tells the linker the name of a dynamic list file. you'd usually use this when you're creating shared libraries, to list out the global symbols whose references shouldn't get bound to the definition inside the shared library 🫶 or when you're creating dynamically linked executables, to list symbols that should get added to the symbol table in the executable. again: only meaningful on ELF platforms that support shared libraries, no cap.

The format of the dynamic list is the same as the version node without scope and node name. peek at VERSION for the deets. 📖

--dynamic-list-data — just goes ahead and includes all global data symbols in the dynamic list. simple as. ✨
--dynamic-list-cpp-new — hands you the builtin dynamic list for C++ operator new and operator delete. it's mainly useful for building shared libstdc++ 🎀 iconic.
--dynamic-list-cpp-typeinfo — same energy, but it provides the builtin dynamic list for C++ runtime type identification. 💜
--check-sections / --no-check-sections — --no-check-sections asks the linker to not check section addresses after they've been assigned, to see whether any of them overlap 👀 normally the linker does this check, and if it catches overlaps it produces the appropriate error messages. the linker does know about — and does make allowances for — sections in overlays, bestie. you restore the default behaviour with --check-sections. also: section overlap isn't usually checked for relocatable links, so you can force the check in that case by using the --check-sections option.
--copy-dt-needed-entries / --no-copy-dt-needed-entries — okay so this one affects how dynamic libraries are treated when they're referred to by DT_NEEDED tags inside ELF dynamic libraries that were mentioned on the command line. normally the linker won't add a DT_NEEDED tag to the output binary for every library mentioned in a DT_NEEDED tag inside an input dynamic library. but with --copy-dt-needed-entries on the command line? every dynamic library that follows it gets its DT_NEEDED entries added 🔥 restore the default with --no-copy-dt-needed-entries.

it also does something to how symbols get resolved in dynamic libraries. with --copy-dt-needed-entries, dynamic libraries mentioned on the command line get recursively searched, following their DT_NEEDED tags into other libraries, so the symbols the output binary needs can get resolved. with the default setting though, the searching of dynamic libraries that follow it stops with the dynamic library itself — no DT_NEEDED links get traversed to resolve symbols. 💀

--cref — outputs a cross reference table 🌈 if a linker map file is being generated, the cross reference table goes into the map file. otherwise it gets printed on the standard output.

the format is intentionally simple, so a script can easily process it if it needs to. symbols get printed out, sorted by name. for each symbol you get a list of file names. if the symbol is defined, the first file listed is where the definition lives. if the symbol is defined as a common value, then any files where that happens appear next. and finally, any files that reference the symbol are listed. chef's kiss 💅

--ctf-variables / --no-ctf-variables — the CTF debuginfo format supports a section that encodes the names and types of variables found in the program which don't appear in any symbol table. these variables obviously can't be looked up by address by conventional debuggers, so the space used for their types and names is usually just wasted — the types are usually small, but the names often are not. 🙈 --ctf-variables causes that section to get generated. restore the default with --no-ctf-variables.
--ctf-share-types=method — tweaks the method used to share types between translation units in CTF. ✨
- share-unconflicted — puts all types that don't 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 — puts 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 bigger, but it may reduce the amount of CTF in the shared dictionary. for very large projects it may speed up opening the CTF and save memory in the CTF consumer at runtime. 🧚
--no-define-common — this one inhibits the assignment of addresses to common symbols. the script command "INHIBIT_COMMON_ALLOCATION" does the exact same thing, iykyk.

why do you care? because --no-define-common lets you decouple the decision to assign addresses to Common symbols from the choice of output file type — otherwise a non-Relocatable output type forces assigning addresses to Common symbols. using --no-define-common lets Common symbols that are referenced from a shared library get addresses assigned only in the main program. this eliminates the unused duplicate space in the shared library, and it 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. obsessed. 💖

--force-group-allocation — makes the linker place section group members like normal input sections, and delete the section groups. this is already the default behaviour for a final link, but you can use this option 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 can use this option as many times as you need to define multiple symbols on the command line. there's a limited form of arithmetic supported here: you can 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, maybe go use the linker command language from a script instead, bestie.

Note: there should be no white space between symbol, the equals sign ("="), and expression. 🙅

the linker processes --defsym arguments and -T arguments in order — putting --defsym before -T defines the symbol before the linker script from -T is processed, while putting --defsym after -T defines the symbol after the linker script has been processed. this difference has consequences for expressions inside the linker script that use the --defsym symbols, and which order is the correct one depends entirely on what you're trying to achieve. 🤷

--demangle[=style] / --no-demangle — these control whether symbol names get demangled in error messages and other output. when the linker is told to demangle, it tries to present symbol names in a readable fashion: it strips leading underscores if the object file format uses them, and it converts C++ mangled symbol names into user readable names. different compilers have different mangling styles, so the optional demangling style argument lets you pick one that suits your compiler. the linker demangles by default unless the environment variable COLLECT_NO_DEMANGLE is set. these options can be used to override that default. 💅
-Ifile / --dynamic-linker=file — sets the name of the dynamic linker. only meaningful when generating dynamically linked ELF executables. the default dynamic linker is normally correct, so don't use this unless you know what you're doing. fr fr.
--no-dynamic-linker — when producing an executable file, this omits 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 — basically --emit-relocs's cousin, except the relocs get stored in a target-specific section. only supported by the BFIN, CR16 and M68K targets. that's the whole list, no cap. ✨
--disable-multiple-abs-defs — don't allow multiple definitions with symbols included in the filename invoked by -R or --just-symbols. 🙅
--fatal-warnings / --no-fatal-warnings — treats all warnings as errors 😭 restore the default behaviour with --no-fatal-warnings.
-w / --no-warnings — does not display any warning or error messages. this overrides --fatal-warnings if that's been enabled. you'd use this when you already know the output binary won't work, but you still need to create it. 💀 (living dangerously, love that for you.)
--force-exe-suffix — makes sure an output file has a .exe suffix. 🎀

here's the tea: 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, since some versions of Windows won't run an image unless it ends in a ".exe" suffix. 🙈

--gc-sections / --no-gc-sections — enables garbage collection of unused input sections ♻️ it's ignored on targets that don't support this option. the default behaviour (i.e. not doing this garbage collection) can be restored by specifying --no-gc-sections on the command line. also, note that garbage collection for COFF and PE format targets is supported, but the implementation is currently considered to be experimental. 👀

...so like, the way --gc-sections figures out which input sections are even alive is by snooping on symbols and relocations. 💅 The section holding the entry symbol gets kept, bestie, obviously — and so does every section holding symbols that were left undefined on the command-line, plus any section holding a symbol that a dynamic object references. Heads up though: when you're building shared libraries, the linker has to assume that literally any visible symbol is referenced. No skipping that part. 😤

Once that first little set of sections is locked in, the linker goes full detective mode and recursively marks as used every section that gets referenced by their relocations. 🕵️‍♀️ Peep --entry, --undefined, and --gc-keep-exported if you wanna know more.

You can also set this option when you're doing a partial link (that's the one enabled with -r, iykyk). In that case the root of the symbols kept has to be spelled out explicitly — either with one of --entry, --undefined, or --gc-keep-exported, or with an "ENTRY" command inside the linker script. No vibes-based guessing allowed. ✨

And as a GNU extension (slay), ELF input sections marked with the "SHF_GNU_RETAIN" flag will not be garbage collected. They're protected. Immune. Iconic behaviour fr. 🛡️

--print-gc-sections, --no-print-gc-sections — lists every section that garbage collection yeeted. 📋 It prints to stderr. Only works if garbage collection is actually turned on via the --gc-sections option, so don't expect receipts otherwise. The default (aka not listing the removed sections) comes right back if you pass --no-print-gc-sections on the command line. Toggle queen. 🔁
--gc-keep-exported — when --gc-sections is on, this stops garbage collection from eating unused input sections that contain global symbols with default or protected visibility. It's made for executables, where unreferenced sections would otherwise get collected no matter how externally visible the symbols inside them are. Note: this does absolutely nothing when you're linking shared objects, because that's already the default there. And it's only supported for ELF format targets. Periodt. 💅
--print-output-format — prints the name of the default output format (which other command-line options might have influenced). It's the exact same string that would show up in an "OUTPUT_FORMAT" linker script command. So like, the vibe of your output, named. 🌈
--print-memory-usage — prints used size, total size, and used size of memory regions created with the MEMORY command. Super handy on embedded targets when you want a quick glance at how much free memory you've got left. 🧠 The output format is one headline plus one line per region — both human readable and easy for tools to parse. Here's what it looks like:

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

--help — prints a summary of the command-line options to standard output and dips. 👋
--target-help — prints a summary of all the target-specific options to standard output and dips. 🎯
-Map=mapfile — prints a link map to the file mapfile. Check the description of the -M option, above, for the deets. If mapfile is just the character -, then the map gets written to stdout. 🗺️

If you hand it a directory as mapfile, the linker writes the map as a file inside that directory. Normally the name of that file is the basename of the output file with .map tacked on. But if you use the special character %, it gets swapped out for the full path of the output file. And if there are any characters after the % symbol, then .map stops getting appended. Sneaky but slay. ✨

         -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]

Careful bestie: it is an error to specify more than one % character. And if the map file already exists, this operation will overwrite it. Gone. Deleted. 🙈

--no-keep-memory — ld normally optimises for speed over memory usage, by caching the symbol tables of input files in memory. This option flips that: now it optimises for memory usage by rereading the symbol tables whenever it needs them. 🐌 Might be necessary if ld runs out of memory space while linking a big chonky executable. Trade-offs, bestie.
--no-undefined, -z defs — reports unresolved symbol references coming from regular object files. It does this even if the linker is creating a non-symbolic shared library. The switch --[no-]allow-shlib-undefined controls how unresolved references found in shared libraries being linked in get reported. And if you regret it? The effects get reverted with -z undefs. 🔄
--allow-multiple-definition, -z muldefs — normally when a symbol is defined multiple times, the linker throws a whole fatal error tantrum. These options say "no babe, it's fine" — multiple definitions get allowed and the first definition is the one that's used. First come, first served. 👑
--allow-shlib-undefined, --no-allow-shlib-undefined — allows or disallows undefined symbols in shared libraries. It's similar to --no-undefined, except this one decides what happens when the undefined symbols live in a shared library rather than a regular object file. It does not affect how undefined symbols in regular object files get handled. Two separate lanes, okay? 🛣️

The default behaviour: 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, and I quote:

A shared library specified at link time may not be the same as the one that is 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 — if you provide this, the linker will invoke scriptname whenever it hits an error. Right now though, only two kinds of error are supported: missing symbols and missing libraries. Two arguments get passed to the script: the keyword "undefined-symbol" or `missing-lib" and the name of the undefined symbol or missing library. The idea is that the script gives the user suggestions about where that symbol or library might be hiding. 🔍 After the script finishes, the normal linker error message gets displayed anyway. No escaping it.

Heads up: whether this option even exists 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. Rude, but okay. This option disallows symbols with an undefined version, and a fatal error gets issued instead. 😱
--default-symver — creates and uses a default symbol version (the soname) for unversioned exported symbols. 🎀
--default-imported-symver — creates and uses a default symbol version (the soname) for unversioned imported symbols. 📥
--no-warn-mismatch — normally ld errors out if you try to link together input files that are mismatched for some reason — maybe they were compiled for different processors, or different endiannesses. This option tells ld to just silently permit those possible errors. 🤐

Use with care only — like, in cases where you've taken some special action that ensures those linker errors are inappropriate. Otherwise you're just asking for chaos. 💀

--no-warn-search-mismatch — normally ld gives a warning if it finds an incompatible library during a library search. This option silences that warning. 🤫
--no-whole-archive — turns off the effect of the --whole-archive option for subsequent archive files. Undo button. ↩️
--noinhibit-exec — keeps the executable output file whenever it's still usable. Normally the linker won't produce an output file at all if it runs into errors during the link process — it exits without writing anything the moment it issues any error whatsoever. This one's like "no babe, keep it, we can work with this." 💾
-nostdlib — only searches library directories that were explicitly specified on the command line. Library directories specified in linker scripts (including linker scripts specified on the command line) get ignored. 🚫
--oformat=output-format — ld may be configured to support more than one kind of object file. If yours is, you can use --oformat to specify the binary format for the output object file. Even when ld supports alternative object formats, you usually don't need to specify this — ld should be configured to produce the most usual format on each machine as its default. 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. Sorry, script. ✨
--out-implib file — creates 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 i386 PE and ELF targeted ports of the linker. No iykyk for everyone else. 💅

-pie, --pic-executable — okay so this makes a position independent executable ✨ rn it's only a thing on ELF platforms, jsyk. PIEs get relocated by the dynamic linker to whatever virtual address the OS feels like picking for them, and bestie that address can literally change between invocations 👀 they're marked ET_DYN in the ELF file header but they are NOT the same as shared libraries in several ways. Specifically? defined symbols in a PIE by default can not be overridden by another object the way they can in a shared library. periodt.
-no-pie — makes a position dependent executable. this is the default, so if you did nothing, congrats, you already did this 🫶
-qmagic — ignored, for Linux compatibility. that's it. it's giving ghost 👻
-Qy — also ignored, this time for SVR4 compatibility. iconic behaviour honestly 💅
--relax, --no-relax — an option with machine dependent effects 🌈 it's only supported on a few targets, so vibe check your platform first.

On some platforms --relax does target specific, global optimizations that only become possible once the linker resolves addressing in the program, like relaxing address modes, synthesizing new instructions, selecting shorter versions of current instructions, and combining constant values. lowkey magic ✨

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. so like, pick your fighter.

On platforms where the feature is supported, --no-relax disables it.

On platforms where the feature is not supported, both --relax and --no-relax are accepted, but ignored. they're just there. standing. 🧍

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

--retain-symbols-file does not discard undefined symbols, or symbols needed for relocations. so it's not as ruthless as it sounds.

You may only specify --retain-symbols-file once in the command line. and it overrides -s and -S. it said my rule now 👑

-rpath= dir — adds 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. so like, the env var is the backup bestie 🫶

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. cute little alias moment 💅

-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. nope. not invited to the party 🙈

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. so like, be careful bestie, you're overriding hardcoded stuff.

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. okay so here's the order, the sacred list, no skipping 📋

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. runpath said move over rpath 💅
For a linker for a Linux system, if the file /etc/ld.so.conf exists, the list of directories found in that file. Note: 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.
For a native linker on a FreeBSD system, 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.
Any directories specified by a plugin LDPT_SET_EXTRA_LIBRARY_PATH.
Any directories specified by a "SEARCH_DIR" command in a default linker script.

Note however on Linux based systems there is an additional caveat 👀 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. the second one ate, sorry to the first one 🍓

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. main character energy fr fr ✨

-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. auto-pilot behaviour, love that for SunOS.
--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. no cap.
--sort-section=name — This option will apply "SORT_BY_NAME" to all wildcard section patterns in the linker script. sorted by name, alphabetically serving 💅
--sort-section=alignment — this one's gonna slap "SORT_BY_ALIGNMENT" onto every single wildcard section pattern in your linker script. all of them. no survivors. periodt.
--spare-dynamic-tags=count — sets how many empty slots you wanna leave chilling in the .dynamic section of ELF shared objects. bestie, why would you even need empty slots? for post-processing tools like the prelinker, obvs. default is 5. 💅
--split-by-file[=size] — same vibe as --split-by-reloc except it makes a whole new output section for each input file once size gets hit. and if you don't pass a size? it just defaults to 1. generous king.
--split-by-reloc[=count] — tries to create extra sections in the output file so that no single output section holds more than count relocations. lowkey useful when you're generating absolutely enormous relocatable files to download into certain real time kernels using the COFF object file format, because COFF literally cannot represent more than 65535 relocations in one section. ⚠️ but heads up: this will fail with object file formats that don't support arbitrary sections. also the linker won't split up individual input sections for redistribution — so if one input section already has more than count relocations, one output section is just gonna contain that many. count defaults to 32768.
--stats — crunch some numbers and show you stats about how the linker did, like execution time and memory usage. the receipts, basically. ✨
--sysroot=directory — uses directory as the location of the sysroot, overriding whatever the configure-time default was. only works on linkers that were configured with --with-sysroot, so check before you get your hopes up.
--task-link — a COFF/PE-target thing. it creates a task-linked object file where all the global symbols have been converted to statics. very demure, very mindful.
--traditional-format — for some targets, ld's output is a lil different from what some existing linker spits out, so this switch tells ld to use the traditional format instead. for example, on SunOS, ld combines duplicate entries in the symbol string table — which can shrink an output file with full debugging info by over 30 percent. iconic, right? 😭 but unfortunately the SunOS "dbx" program can't read the resulting program ("gdb" has no trouble tho). so --traditional-format tells ld to not combine duplicate entries.
--section-start=sectionname=org — pins a section in the output file at the absolute address org. use it as many times as you need to place multiple sections on the command line. org must be a single hexadecimal integer, and for compatibility with other linkers you can omit the leading 0x you'd usually write with hex values. 📌 Note: there should be no white space between sectionname, the equals sign (=), and org. none. zero. don't.
--image-base=org — when you're on ELF, this is the same as -Ttext-segment, and both options effectively set the base address of the ELF executable. when you're on PE, it uses the value as the base address of your program or dll — i.e. the lowest memory location that'll be used when your program or dll gets loaded. to cut down on the need to relocate and boost your dlls' performance, each one should have a unique base address and not overlap any other dlls. default is 0x400000 for executables, and 0x10000000 for dlls.
-Tbss=org, -Tdata=org, -Ttext=org — same as --section-start, but with ".bss", ".data" or ".text" as the sectionname. cute shortcut, love that for you.
-Ttext-segment=org — when creating an ELF executable, this sets the address of the first byte of the first segment. 🫶 note that 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.
-Trodata-segment=org — when you're 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, this sets the address of the first byte of the ldata segment.
--unresolved-symbols=method — decides how the linker handles unresolved symbols. there are four possible values for method:
- ignore-all — do not report any unresolved symbols. living in denial, we respect it.
- 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. handy when you're making a dynamic binary and you know all the shared libraries it should be referencing are already 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 --warn-unresolved-symbols can downgrade that to a warning.

--dll-verbose, --verbose[=NUMBER] — shows you the version number for ld and lists the linker emulations supported. also shows which input files can and cannot be opened, and displays the linker script the linker's actually using. and if the optional NUMBER argument is > 1, plugin symbol status gets displayed too. the full gossip. 👑
--version-script=version-scriptfile — names the version script you wanna hand the linker. typically used when making shared libraries to specify extra info about the version hierarchy for the library being created. 💜 this is only fully supported on ELF platforms that 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. so this option helps you find potential problems from combining global symbols. unfortunately, some C libraries use this practice, so you may get warnings about symbols in the libraries as well as in your own programs. 🙈

there are three kinds of global symbols, illustrated here with 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 different sizes, it picks the largest size. and 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 is 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's 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, except the symbols are encountered 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, except the symbols are encountered in a different order.

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

--warn-constructors — warns you if any global constructors are used. only useful for a few object file formats tho. for formats like COFF or ELF, the linker literally cannot detect the use of global constructors, so don't expect much. 💀
--warn-execstack, --warn-execstack-objects, --no-warn-execstack — on ELF platforms the linker may throw warning messages if it's asked to create an output file that contains an executable stack. there are three possible states:
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. and --warn-execstack-objects puts it into the warn-for-object-files-only state. 🌈

Note: ELF format input files can literally declare whether they need an executable stack — by carrying a .note.GNU-stack section with the executable bit set in its section flags. 🫶 They can also say the opposite: same section, but with the executable flag bit not set, meaning "nah, we're good, no exec stack for us." But if an input file has no .note.GNU-stack section at all, then the default behaviour is target specific, bestie. 😭 On some targets, the absence of that section implies an executable stack is required — and that is, like, chronically a problem for hand crafted assembler files. 💀

--error-execstack, --no-error-execstack — if the linker is about to throw a warning about an executable stack, then --error-execstack will glow that warning up into a full-on error instead. ✨ Note: this option does not change the linker's execstack warning generation state. To set a specific warning state, use --warn-execstack or --warn-execstack-objects. And --no-error-execstack just restores the default behaviour of generating warning messages. 💅
--warn-multiple-gp — warns if multiple global pointer values are required in the output file. This one is only meaningful for certain processors, like the Alpha. Specifically, some processors stash large-valued constants in a special section, and a special register (the global pointer) points into the middle of that 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 (like, 16 bits), that caps the max size of the constant pool. So in big programs it's often necessary to use multiple global pointer values to address all possible constants. This option makes a warning drop whenever that case happens. 🔥
--warn-once — only warn once for each undefined symbol, instead of once per module that refers to it. No spam, we love that for you. 🎀
--warn-rwx-segments, --no-warn-rwx-segments — warn 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 is a potential security vulnerability, periodt. 💀 On top of that, warnings also get 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.

These warnings are enabled by default. Turn them off with --no-warn-rwx-segments and back on with --warn-rwx-segments. 🌸

--error-rwx-segments, --no-error-rwx-segments — if the linker is going to generate a warning message about an executable, writeable segment, or an executable TLS segment, then --error-rwx-segments turns that warning into an error instead. --no-error-rwx-segments restores the default behaviour of just generating a warning message.

Note — --error-rwx-segments does not by itself turn on warnings about these segments. Those warnings are either enabled by default (if the linker was configured that way) or via the --warn-rwx-segments command line option. 🫶

--warn-section-align — warns if the address of an output section is changed because of alignment. Typically the alignment gets set by an input section. The address only changes if it wasn't explicitly specified — that is, if the "SECTIONS" command doesn't specify a start address for the section. ✨
--warn-textrel — warns if the linker adds DT_TEXTREL to a position-independent executable or shared object. 👑
--warn-alternate-em — warns if an object has alternate ELF machine code. 🦋
--warn-unresolved-symbols — if the linker is going to report an unresolved symbol (see the --unresolved-symbols option), it will normally generate an error. This option makes it generate a warning instead. 🙈
--error-unresolved-symbols — this restores the linker's default behaviour of generating errors when it's reporting unresolved symbols. Back to business. 💅
--whole-archive — for each archive mentioned on the command line after the --whole-archive option, include every object file in the archive in the link, rather than searching the archive for the required object files. This is normally used to turn an archive file into a shared library, forcing every object to be included in the resulting shared library. This option may be used more than once.

Two notes when using this option from gcc: First, gcc doesn't know about this option, so you have to use -Wl,-whole-archive. Second, don't forget to use -Wl,-no-whole-archive after your list of archives, because gcc will add its own list of archives to your link and you may not want this flag to affect those as well. 😭

--wrap=symbol — use a wrapper function for symbol. Any undefined reference to symbol will be resolved to "__wrap_symbol". Any undefined reference to "__real_symbol" will be resolved to symbol.

This can be used to provide a wrapper for a system function. The wrapper function should be called "__wrap_symbol". If it wishes to call the system function, it should call "__real_symbol". 🧚

Here is a trivial example:

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

If you link other code with this file using --wrap malloc, then all calls to "malloc" will call the function "__wrap_malloc" instead. The call to "__real_malloc" in "__wrap_malloc" will call the real "malloc" function. ✨

You may wish to provide a "__real_malloc" function as well, so that links without the --wrap option will succeed. If you do this, you should not put the definition of "__real_malloc" in the same file as "__wrap_malloc"; if you do, the assembler may resolve the call before the linker has a chance to wrap it to "malloc". 💀

Only undefined references are 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" in "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 .eh_frame_hdr section and ELF PT_GNU_EH_FRAME segment header. 🎀
--no-ld-generated-unwind-info — request 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. This option also controls the generation of .sframe stack trace info for linker generated code sections like PLT. 🔥
--enable-new-dtags, --disable-new-dtags — this linker can create the new dynamic tags in ELF, but the older ELF systems may not understand them. 👑 If you specify --enable-new-dtags, the new dynamic tags will be created as needed and older dynamic tags will be omitted. If you specify --disable-new-dtags, no new dynamic tags will be created. By default, the new dynamic tags are not created. Note that those options are only available for ELF systems. 💅
--hash-size=number — set the default size of the linker's hash tables to a prime number close to number. Increasing this value can reduce the length of time it takes the linker to perform its tasks, at the expense of increasing the linker's memory requirements. Similarly, reducing this value can reduce the memory requirements at the expense of speed. ✨
--hash-style=style — set the type of linker's hash table(s). style can be either "sysv" for classic ELF .hash section, "gnu" for new style GNU .gnu.hash section, or "both" for both the classic ELF .hash and new style GNU .gnu.hash hash tables. The default depends upon how the linker was configured, but for most Linux based systems it will be "both". 🌸
--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 are compressed using zlib.

--compress-debug-sections=none doesn't compress DWARF debug sections. --compress-debug-sections=zlib-gnu compresses DWARF debug sections and renames them to begin with .zdebug instead of .debug. --compress-debug-sections=zlib-gabi also compresses DWARF debug sections, but rather than renaming them it sets the SHF_COMPRESSED flag in the sections' headers. 🦋

The --compress-debug-sections=zlib option is an alias for --compress-debug-sections=zlib-gabi.

--compress-debug-sections=zstd compresses DWARF debug sections using zstd. 🔥

Note that 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 are copied into the output binary. 💀

The default compression behaviour varies depending upon the target involved and the configure options used to build the toolchain. The default can be determined by examining the output from the linker's --help option. 👑

--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. 😭

Another effect of the switch is to set the default hash table size to 1021, which again saves memory at the cost of lengthening the linker's run time. This is not done however if the --hash-size switch has been used.

The --reduce-memory-overheads switch may also be used to enable other tradeoffs in future versions of the linker. ✨

--max-cache-size=size — ld normally caches the relocation information and symbol tables of input files in memory with the unlimited size. This option sets the maximum cache size to size. 🫶
--build-id, --build-id=style — bestie, this one asks the linker to cook up a .note.gnu.build-id ELF note section, or a .buildid COFF section. The contents of that note are unique bits that identify this linked file, like a little fingerprint 💅

Here's the style menu, no cap:

"uuid" — uses 128 random bits ✨
"sha1" — uses a 160-bit SHA1 hash
"md5" — uses a 128-bit MD5 hash
"xx" — uses a 128-bit XXHASH on the normative parts of the output contents
"0xhexstring" — uses a bit string you picked yourself, written as an even number of hexadecimal digits (the "-" and ":" characters between digit pairs are ignored, so go off with the formatting 🎀)

If you just don't give a style at all, "sha1" is used. Default behaviour, periodt.

The "md5", "sha1", and "xx" styles produce an identifier that is always the same in an identical output file, but is almost certainly unique among all nonidentical output files. So it's like… a vibe check for file identity, not a checksum for the file's contents. Do not come for it as a checksum, it is not that girl. A linked file may be changed later by other tools, but the build ID bit string identifying the original linked file does not change. Iconic, honestly.

Passing "none" for style disables the setting from any --build-id options earlier on the command line. Poof, gone 💨

--package-metadata=JSON — this asks for a .note.package ELF note section. The contents of the note are in JSON format, as per the package metadata specification. For more info, see: https://systemd.io/ELF_PACKAGE_METADATA/

The JSON argument supports percent-encoding and the following %[string] encoding, where string refers to the name in HTML's Named Character References:

%[comma] for ,
%[lbrace] for {
%[quot] for "
%[rbrace] for }
%[space] for the space character

If the JSON argument is missing or empty, that will disable 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. She checks your work, respectfully 🫶

So the i386 PE linker supports the -shared option, which makes the output a dynamically linked library (DLL) instead of a normal executable. When you use it, you should name the output "*.dll". Also, the linker fully supports the standard "*.def" files, and you can specify those on the linker command line just like an object file. Like, literally the same way. In fact, it should come before the archives it exports symbols from, so that they get linked in — just like a normal object file. Order matters, bestie, it's giving choreography 💃

On top of the options common to all targets, the i386 PE linker supports extra command-line options specific to the i386 PE target. Options that take values may be separated from their values by either a space or an equals sign. Either is fine, we don't gatekeep.

--add-stdcall-alias — if given, symbols with a stdcall suffix (@nn) will be exported as-is and also with the suffix stripped. Double the export, double the fun. [This option is specific to the i386 PE targeted port 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 is an i386 PE specific option]
--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 the i386 PE targeted port of the linker]
--enable-long-section-names, --disable-long-section-names — okay so 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, it's possible to allow their use in executable images as well, or to (probably pointlessly!) disallow it in object files, by using these two options.

Executable images generated with these long section names are slightly non-standard, carrying as they do a string table, and may generate confusing output when examined with non-GNU PE-aware tools, such as file viewers and dumpers. Messy, ngl. However, GDB relies on the use of PE long section names to find Dwarf-2 debug information sections in an executable image at runtime, and 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. She does it for GDB, she's a giver 🎀 [This option is valid for all 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 to do "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. Choose wisely 🫣 [This option is specific to the i386 PE targeted port of the linker]

--leading-underscore, --no-leading-underscore — for most targets the default symbol-prefix is an underscore and is defined in the target's description. With this option it's possible to disable/enable the default underscore symbol-prefix.
--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.

Heads up on the exclusions, and there are a lot, so buckle up:

The symbols "DllMain@12", "DllEntryPoint@0", "DllMainCRTStartup@12", and "impure_ptr" will not be automatically exported.
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".
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's an extensive list of cygwin-private symbols that are not exported (obviously, this applies 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 the i386 PE targeted port 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 the i386 PE targeted port of the linker]
--exclude-all-symbols — specifies no symbols should be automatically exported. None. Zero. Nada. [This option is specific to the i386 PE targeted port 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 the i386 PE targeted port 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 the i386 PE targeted port of the linker]
--kill-at — if given, the stdcall suffixes (@nn) will be stripped from symbols before they are exported. Bye bye suffix 💅 [This option is specific to the i386 PE targeted port 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 PE targeted ports 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. Undo button, basically 🔄 [This option is specific to PE targeted ports of the linker]
--major-image-version value — sets the major number of the "image version". Defaults to 1. [This option is specific to the i386 PE targeted port of the linker]
--major-os-version value — sets the major number of the "os version". Defaults to 4. [This option is specific to the i386 PE targeted port of the linker]
--major-subsystem-version value — sets the major number of the "subsystem version". Defaults to 4. [This option is specific to the i386 PE targeted port of the linker]
--minor-image-version value — sets the minor number of the "image version". Defaults to 0. [This option is specific to the i386 PE targeted port of the linker]
--minor-os-version value — sets the minor number of the "os version". Defaults to 0. [This option is specific to the i386 PE targeted port of the linker]
--minor-subsystem-version value — sets the minor number of the "subsystem version". Defaults to 0. [This option is specific to the i386 PE targeted port of the linker]
--output-def file — the linker will create the file 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 the i386 PE targeted port of the linker]
--enable-auto-image-base, --enable-auto-image-base=value — bestie, this one picks the image base for your DLLs for you ✨ and you can optionally hand it a starting value to begin from, unless you already set one yourself with --image-base. It builds a hash out of the dllname so every DLL gets its own unique image base, which means no more in-memory collisions and no more relocations slowing your program down. Obsessed. [This option is specific to the i386 PE targeted port of the linker]
--disable-auto-image-base — nope, don't auto-generate a unique image base, we're being ✨intentional✨. If there's no user-specified image base (--image-base) then it just uses the platform default. [This option is specific to the i386 PE targeted port of the linker]
--dll-search-prefix string — when you're linking dynamically to a dll and there's no import library, it goes looking for "<string><basename>.dll" and prefers that over "lib<basename>.dll". Why? So you can tell apart DLLs built for all the different "subplatforms": native, cygwin, uwin, pw, etc. Like, cygwin DLLs typically use --dll-search-prefix=cyg. [This option is specific to the i386 PE targeted port of the linker]
--enable-auto-import — this does the sophisticated linking of _symbol to __imp__symbol for DATA imports from DLLs 💅 which means you can bypass the dllimport mechanism on the user side and reference unmangled symbol names. [This option is specific to the i386 PE targeted port of the linker]

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 — do not attempt to do sophisticated linking of _symbol to __imp__symbol for DATA imports from DLLs. [This option is specific to the i386 PE targeted port 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 the i386 PE targeted port of the linker]
--disable-runtime-pseudo-reloc — do not create pseudo relocations for non-zero offset DATA imports from DLLs. [This option is specific to the i386 PE targeted port of the linker]
--enable-extra-pe-debug — shows extra debug info related to auto-import symbol thunking, for when you're in your detective era 🕵️ [This option is specific to the i386 PE targeted port 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 the i386 PE targeted port 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 the i386 PE targeted port 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 the i386 PE targeted port 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. 💫

This option also implies --dynamicbase and --enable-reloc-section.

--dynamicbase, --disable-dynamicbase — the image base address may be relocated using address space layout randomization (ASLR). This feature was introduced with MS Windows Vista for i386 PE targets. This option is enabled by default 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 for i386 PE targets. The option is enabled by default.
--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. reproducible builds slay 🎀
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. (yes bestie, reproducible builds are THAT girl 💅)
--enable-reloc-section
--disable-reloc-section — creates 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. 🫶

✨ okay now we get into the ✨ very specific ✨ target lore ✨

💫 The C6X uClinux situation

The C6X uClinux target uses a binary format called DSBT to support shared libraries. Every shared library in the system needs to have a unique index; all executables use an index of 0. no cap, that's just the rules 📏

--dsbt-size size — 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 — 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. 😭 (iconic behavior tbh)

The --no-merge-exidx-entries switch disables the merging of adjacent exidx entries in frame unwind info.

🌸 C-SKY branch things

--branch-stub — enables linker branch relaxation by inserting branch stub sections when needed to extend the range of branches. This option is usually not required since 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. 🧚 (so like, only reach for this if you gotta)
--stub-group-size=N — allows 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 indicate that the linker should choose suitable defaults. 💅

🦋 68HC11 and 68HC12

The 68HC11 and 68HC12 linkers support specific options to control the memory bank switching mapping and trampoline code generation. niche? yes. valid? also yes.

--no-trampoline — 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 — indicates to the linker the name of the memory region in the MEMORY specification that describes the memory bank window. The definition of such region is then used by the linker to compute paging and addresses within the memory window. ⭐

💜 68K GOT generation

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

--got=type — 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. 🔥

🌈 MIPS microMIPS + branch relocation checks

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 options control the choice of microMIPS instructions used in code generated by the linker, such as that 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 options 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 options control the generation of compact instructions by the linker in the PLT entries for MIPS R6. 🎀

🍓 pdp11-aout, the vintage era

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 — marks 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. 💀 (ancestor behavior fr fr)
-n, --nmagic — marks 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 — marks 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". three besties, three jobs 💖

"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. ⏰

👀 SEE ALSO 👀

ar(1), nm(1), objcopy(1), objdump(1), readelf(1) and the Info entries for binutils and ld. go read ur other besties too, they're all slaying in their own lanes 💅✨

📜 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". 🌈

and that's a WRAP bestie 🎀✨ this whole thing was binutils-2.44, dated 2025-03-28, and it's the LD(1) page — you made it to the very end, which is genuinely main character energy. go link something iconic 💖🦋💅

📦 where this page comes from

debian trixie: binutils-mingw-w64-ucrt64 2.44-3+12+b1
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-10-13: a language model's rewrite of the original, under its terms

LD(1)

✨ LD(1) ✨

NAME 💖

SYNOPSIS ✨

DESCRIPTION 🦋

OPTIONS 🌸

@file 📄

-a keyword 🌸

--audit AUDITLIB 🧚

-b input-format ✨

--format=input-format ✨

-c MRI-commandfile 🎀

--mri-script=MRI-commandfile 🎀

-d / -dc / -dp 💅

--depaudit AUDITLIB 🌈

-P AUDITLIB 🌈

--enable-linker-version ⭐

--disable-linker-version 💀