LLVM-SYMBOLIZER(1)

💖 llvm-symbolizer 💖

okay bestie, welcome to the LLVM-SYMBOLIZER(1) manual from the LLVM fam — this is the page for turning addresses into source code locations, and it’s genuinely iconic debugger-bestie energy fr fr.

🎀 NAME 🎀

llvm-symbolizer — convert addresses into source code locations.

✨ SYNOPSIS ✨

llvm-symbolizer [options] [addresses...]

🦋 DESCRIPTION 🦋

okay so llvm-symbolizer reads input names and addresses from the command-line and prints the corresponding source code locations to standard output. it can also symbolize logs containing Symbolizer Markup via --filter-markup. no cap, that’s the whole main-character job.

If no address is specified on the command-line, it reads the addresses from standard input. If no input name is specified on the command-line, but addresses are, or if at any time an input value is not recognized, the input is simply echoed to the output. like, it just sends it right back, lowkey.

Input names can be specified together with the addresses either on standard input or as positional arguments on the command-line. By default, input names are interpreted as object file paths. However, prefixing a name with BUILDID: states that it is a hex build ID rather than a path — that will look up the corresponding debug binary. For consistency, prefixing a name with FILE: explicitly states that it is an object file path (which is the default). iykyk.

A positional argument or standard input value can be preceded by "DATA" or "CODE" to indicate that the address should be symbolized as data or executable code respectively. If neither is specified, "CODE" is assumed. DATA is symbolized as address and symbol size rather than line number. periodt.

llvm-symbolizer parses options from the environment variable LLVM_SYMBOLIZER_OPTS after parsing options from the command line. LLVM_SYMBOLIZER_OPTS is primarily useful for supplementing the command-line options when llvm-symbolizer is invoked by another program or runtime. bestie, it’s the little options sidecar.

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🧪 EXAMPLES 🧪

All of the following examples use the following two source files as input. They use a mixture of C-style and C++-style linkage to illustrate how these names are printed differently (see --demangle).

// test.h
extern "C" inline int foz() {
  return 1234;
}

// test.cpp
#include "test.h"
int bar=42;

int foo() {
  return bar;
}

int baz() {
  volatile int k = 42;
  return foz() + k;
}

int main() {
  return foo() + baz();
}

These files are built as follows:

$ clang -g test.cpp -o test.elf
$ clang -g -O2 test.cpp -o inlined.elf

🧪 Example 1 - addresses and object on command-line:

$ llvm-symbolizer --obj=test.elf 0x4004d0 0x400490
foz
/tmp/test.h:1:0

baz()
/tmp/test.cpp:11:0

🌸 Example 2 - addresses on standard input:

$ cat addr.txt
0x4004a0
0x400490
0x4004d0
$ llvm-symbolizer --obj=test.elf < addr.txt
main
/tmp/test.cpp:15:0

baz()
/tmp/test.cpp:11:0

foz
/tmp/./test.h:1:0

🦋 Example 3 - object specified with address:

$ llvm-symbolizer "test.elf 0x400490" "FILE:inlined.elf 0x400480"
baz()
/tmp/test.cpp:11:0

foo()
/tmp/test.cpp:8:10

$ cat addr2.txt
FILE:test.elf 0x4004a0
inlined.elf 0x400480

$ llvm-symbolizer < addr2.txt
main
/tmp/test.cpp:15:0

foo()
/tmp/test.cpp:8:10

💅 Example 4 - BUILDID and FILE prefixes:

$ llvm-symbolizer "FILE:test.elf 0x400490" "DATA BUILDID:123456789abcdef 0x601028"
baz()
/tmp/test.cpp:11:0

bar
6295592 4

$ cat addr3.txt
FILE:test.elf 0x400490
DATA BUILDID:123456789abcdef 0x601028

$ llvm-symbolizer < addr3.txt
baz()
/tmp/test.cpp:11:0

bar
6295592 4

🎀 Example 5 - CODE and DATA prefixes:

$ llvm-symbolizer --obj=test.elf "CODE 0x400490" "DATA 0x601028"
baz()
/tmp/test.cpp:11:0

bar
6295592 4

$ cat addr4.txt
CODE test.elf 0x4004a0
DATA inlined.elf 0x601028

$ llvm-symbolizer < addr4.txt
main
/tmp/test.cpp:15:0

bar
6295592 4

🌈 Example 6 - path-style options:

This example uses the same source file as above, but the source file's full path is /tmp/foo/test.cpp and is compiled as follows. The first case shows the default absolute path, the second --basenames, and the third shows --relativenames.

$ pwd
/tmp
$ clang -g foo/test.cpp -o test.elf
$ llvm-symbolizer --obj=test.elf 0x4004a0
main
/tmp/foo/test.cpp:15:0
$ llvm-symbolizer --obj=test.elf 0x4004a0 --basenames
main
test.cpp:15:0
$ llvm-symbolizer --obj=test.elf 0x4004a0 --relativenames
main
foo/test.cpp:15:0

✨ OPTIONS ✨

• --adjust-vma <offset> — adds that offset to object file addresses while doing lookups, so it's like the object got relocated by the offset. iykyk 🎀
• --basenames, -s — prints just the file's name with no directories at all, instead of the absolute path. no folder drama 💅
• --build-id — looks up the object using the build ID you give it, as a hexadecimal string. mutually exclusive with --obj, bestie — pick one 🦋
• --color [=<always|auto|never>] — says whether to use color in --filter-markup mode. defaults to auto, which sniffs out whether standard output even supports color. and if you just say --color all by itself, that's the same as --color=always ✨
• --debug-file-directory <path> — hands the tool a path to a directory that has a .build-id subdirectory, so it can go hunting for debug information for stripped binaries. if you pass this multiple times, they get searched in the order you gave them 🔍
• --debuginfod, --no-debuginfod — toggles whether debuginfod lookups happen for debug binaries. unless you say otherwise, debuginfod is only enabled if libcurl was compiled in (LLVM_ENABLE_CURL) and at least one server URL came in through the environment variable DEBUGINFOD_URLS. two conditions, no skipping 🌸
• --demangle, -C — prints demangled function names when the names are mangled (so the mangled name _Z3bazv becomes baz(), while the non-mangled name foz gets printed exactly as it is). defaults to true — yes, it's already on, you're welcome 💖
• --dwp <path> — uses the DWP file sitting at <path> for any CUs that have split DWARF debug data 🧚
• --fallback-debug-path <path> — when a separate file holds the debug data and a GNU debug link section points at it, this path becomes the basis for locating that debug data whenever it can't be found relative to the object. a little backup plan 🫶
• --filter-markup — reads from standard input, converts the Symbolizer Markup inside into human-readable form, and prints the results to standard output. heads up: these markup elements are not yet supported:
  • {{{hexdict}}}
  • {{{dumpfile}}}

the {{{bt}}} backtrace element reports frames using this syntax:

#<number>[.<inline>] <address> <function> <file>:<line>:<col>
(<module>+<relative address>)

<inline> gives you frame numbers for calls inlined into the caller corresponding to <number>. the inlined call numbers start at 1 and grow from callee to caller 📈

<address> is an address inside the call instruction to the function — so yeah, it might not be the start of the instruction, don't come for me. <relative address> is the corresponding virtual offset in the <module> loaded at that address ⭐

• --functions [=<none|short|linkage>], -f — controls how function names get printed: omit the function name, print the short function name, or print the full linkage name (that's none, short, linkage, in order). defaults to linkage 👑
• --help, -h — shows help and usage for this command. the classic 🎀
• --inlining, --inlines, -i — if a source code location is inside an inlined function, prints all the inlined frames. this is the default, so it's already doing the most 💅
• --no-inlines — don't print inlined frames. simple as that 🙈
• --no-demangle — don't print demangled function names. the opposite of the vibe above 💀
• --obj <path>, --exe, -e — path to the object file that's getting symbolized. if you specify -, it reads the object straight from the standard input stream. mutually exclusive with --build-id 🦋
• --output-style <LLVM|GNU|JSON> — picks the preferred output style. defaults to LLVM. when it's set to GNU, the tool follows the style of GNU's addr2line. the differences from the LLVM style are:
  • it does not print the column of a source code location.
  • it does not add an empty line after the report for an address.
  • it does not replace the name of an inlined function with the name of the topmost caller when inlined frames aren't shown.
  • it does print an address's debug-data discriminator when it's non-zero. one way to produce discriminators is to compile with clang's -fdebug-info-for-profiling.

JSON style gives you a machine readable output in JSON. if addresses are supplied via stdin, the output JSON is a series of individual objects; otherwise all the results live in a single array 🌈

$ llvm-symbolizer --obj=inlined.elf 0x4004be 0x400486 -p
baz() at /tmp/test.cpp:11:18
 (inlined by) main at /tmp/test.cpp:15:0

foo() at /tmp/test.cpp:6:3

$ llvm-symbolizer --output-style=LLVM --obj=inlined.elf 0x4004be 0x400486 -p --no-inlines
main at /tmp/test.cpp:11:18

foo() at /tmp/test.cpp:6:3

$ llvm-symbolizer --output-style=GNU --obj=inlined.elf 0x4004be 0x400486 -p --no-inlines
baz() at /tmp/test.cpp:11
foo() at /tmp/test.cpp:6

$ clang -g -fdebug-info-for-profiling test.cpp -o profiling.elf
$ llvm-symbolizer --output-style=GNU --obj=profiling.elf 0x401167 -p --no-inlines
main at /tmp/test.cpp:15 (discriminator 2)

$ llvm-symbolizer --output-style=JSON --obj=inlined.elf 0x4004be 0x400486 -p
[
  {
    "Address": "0x4004be",
    "ModuleName": "inlined.elf",
    "Symbol": [
      {
        "Column": 18,
        "Discriminator": 0,
        "FileName": "/tmp/test.cpp",
        "FunctionName": "baz()",
        "Line": 11,
        "StartAddress": "0x4004be",
        "StartFileName": "/tmp/test.cpp",
        "StartLine": 9
      },
      {
        "Column": 0,
        "Discriminator": 0,
        "FileName": "/tmp/test.cpp",
        "FunctionName": "main",
        "Line": 15,
        "StartAddress": "0x4004be",
        "StartFileName": "/tmp/test.cpp",
        "StartLine": 14
      }
    ]
  },
  {
    "Address": "0x400486",
    "ModuleName": "inlined.elf",
    "Symbol": [
      {
        "Column": 3,
        "Discriminator": 0,
        "FileName": "/tmp/test.cpp",
        "FunctionName": "foo()",
        "Line": 6,
        "StartAddress": "0x400486",
        "StartFileName": "/tmp/test.cpp",
        "StartLine": 5
      }
    ]
  }
]

• --pretty-print, -p — prints human readable output. if --inlining is specified, the enclosing scope gets prefixed by (inlined by). for JSON output, this option makes the JSON indented and split over new lines; otherwise the JSON prints in a compact form. slay 🌸

$ llvm-symbolizer --obj=inlined.elf 0x4004be --inlining --pretty-print
baz() at /tmp/test.cpp:11:18
 (inlined by) main at /tmp/test.cpp:15:0

• --print-address, --addresses, -a — prints the address before the source code location. defaults to false 💜

$ llvm-symbolizer --obj=inlined.elf --print-address 0x4004be
0x4004be
baz()
/tmp/test.cpp:11:18
main
/tmp/test.cpp:15:0

$ llvm-symbolizer --obj=inlined.elf 0x4004be --pretty-print --print-address
0x4004be: baz() at /tmp/test.cpp:11:18
 (inlined by) main at /tmp/test.cpp:15:0

• --print-source-context-lines <N> — prints N lines of source context for each symbolized address 🎀

$ llvm-symbolizer --obj=test.elf 0x400490 --print-source-context-lines=3
baz()
/tmp/test.cpp:11:0
10  :   volatile int k = 42;
11 >:   return foz() + k;
12  : }

• --relativenames — prints the file's path relative to the compilation directory instead of the absolute path. and if the command-line to the compiler included the full path, this ends up being the same as the default. literally identical vibes at that point 🦋
• --verbose — prints verbose address, line and column information. the full tea ☕

$ llvm-symbolizer --obj=inlined.elf --verbose 0x4004be
baz()
  Filename: /tmp/test.cpp
  Function start filename: /tmp/test.cpp
  Function start line: 9
  Function start address: 0x4004b6
  Line: 11
  Column: 18
main
  Filename: /tmp/test.cpp
  Function start filename: /tmp/test.cpp
  Function start line: 14
  Function start address: 0x4004b0
  Line: 15
  Column: 18

• --version, -v — prints version information for the tool 👑
• @<FILE> — reads command-line options from the response file <FILE>. cute little options-in-a-file moment 🎀

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💻 WINDOWS/PDB SPECIFIC OPTIONS 💻

• --dia — uses the Windows DIA SDK for symbolization. if the DIA SDK isn't found, llvm-symbolizer falls back to the native implementation. no cap, it's got a backup plan 🫶

🍎 MACH-O SPECIFIC OPTIONS 🍎

• --default-arch <arch> — if a binary contains object files for multiple architectures (think a Mach-O universal binary), this symbolizes the object file for the given architecture. you can also specify the architecture by writing binary_name:arch_name in the input (example right below 👇). if the architecture isn't specified in either way, the address will not be symbolized. defaults to empty string — yes, empty 💀

$ cat addr.txt
/tmp/mach_universal_binary:i386 0x1f84
/tmp/mach_universal_binary:x86_64 0x100000f24

$ llvm-symbolizer < addr.txt
_main
/tmp/source_i386.cc:8

_main
/tmp/source_x86_64.cc:8

• --dsym-hint <path/to/file.dSYM> — if the debug info for a binary isn't chilling in the default location, look for it at the .dSYM path you hand over here. this flag can be used multiple times, stack 'em up 🧚

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🚪 EXIT STATUS 🚪

llvm-symbolizer returns 0. any other exit code means there's an internal program error — so if you see something else, that's a whole thing 😭

👀 SEE ALSO 👀

llvm-addr2line(1) — go read that one too, bestie 💖

🫶 AUTHOR 🫶

Maintained by the LLVM Team (https://llvm.org/).

©️ COPYRIGHT ©️

2003-2023, LLVM Project

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okay that's the whole page, we did it 🎉 this one's LLVM-SYMBOLIZER(1), version/source line 17, dated 2023-12-01 — iconic, historic, periodt 💅✨