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[llvm-nm] Add --line-numbers flag
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This parallels the binutils/BSD flag of the same name. Debugging
information is loaded to print line number information for symbols.
Defined symbols are symbolized by their section addresses, and undefined
symbols by their first text reloc with line info.

Differential Revision: https://reviews.llvm.org/D150987
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@mysterymath
mysterymath committed Sep 19, 2023
1 parent 86b32c4 commit c649f29
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6 changes: 6 additions & 0 deletions llvm/docs/CommandGuide/llvm-nm.rst
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Expand Up @@ -190,6 +190,12 @@ OPTIONS

Print just the symbol names. Alias for `--format=just-symbols``.

.. option:: --line-numbers, -l

Use debugging information to print the filenames and line numbers where
symbols are defined. Undefined symbols have the location of their first
relocation printed instead.

.. option:: -m

Use Darwin format. Alias for ``--format=darwin``.
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3 changes: 3 additions & 0 deletions llvm/docs/ReleaseNotes.rst
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Expand Up @@ -177,6 +177,9 @@ Changes to the LLVM tools
* llvm-readelf now supports ``--extra-sym-info`` (``-X``) to display extra
information (section name) when showing symbols.

* ``llvm-nm`` now supports the ``--line-numbers`` (``-l``) option to use
debugging information to print symbols' filenames and line numbers.

Changes to LLDB
---------------------------------

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240 changes: 240 additions & 0 deletions llvm/test/tools/llvm-nm/X86/line-numbers.test
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@@ -0,0 +1,240 @@
## Check that printing line numbers isn't attempted for files like bitcode,
## which have symbols but limited/no section or debug info.
# RUN: llvm-nm --line-numbers %p/Inputs/test.IRobj-x86_64 | FileCheck %s --check-prefix=BITCODE --match-full-lines --implicit-check-not={{.}}
# BITCODE: ---------------- S _global_const
# BITCODE-NEXT: ---------------- D _global_data
# BITCODE-NEXT: ---------------- T _global_func
# BITCODE-NEXT: ---------------- S _hidden_const
# BITCODE-NEXT: ---------------- D _hidden_data
# BITCODE-NEXT: ---------------- T _hidden_func
# BITCODE-NEXT: ---------------- s _static_const
# BITCODE-NEXT: ---------------- d _static_data
# BITCODE-NEXT: ---------------- t _static_func

## Check that various symbol types can use debug information if available to
## print line numbers, and if unavailable, don't print anything erroneous. The
## specific cases checked are given by the symbol names below. Other test cases
## place requirements on the contents of the whole file, so they are kept out
## of main.o.
# RUN: rm -rf %t
# RUN: split-file %s %t
# RUN: llvm-mc -g --filetype=obj %t/main.s -o %t/main.o
# RUN: llvm-nm -l %t/main.o | FileCheck %s --match-full-lines --implicit-check-not={{.}}
# RUN: llvm-nm --line-numbers %t/main.o | FileCheck %s --match-full-lines --implicit-check-not={{.}}

# CHECK: 0000000000001234 a absolute_symbol
# CHECK-NEXT: 0000000000000000 d data_no_dwarf
# CHECK-NEXT: 0000000000000000 T defined_global_function [[FILENAME:.*main.s]]:4
# CHECK-NEXT: 0000000000000001 t defined_local_function [[FILENAME]]:7
# CHECK-NEXT: 0000000000000000 t function_no_dwarf
# CHECK-NEXT: U undef1 [[FILENAME]]:12
# CHECK-NEXT: U undef2 [[FILENAME]]:14
# CHECK-NEXT: U undef_no_reloc
# CHECK-NEXT: 0000000000000002 t undefined_references [[FILENAME]]:12

## Check that in the absence of DWARF in the whole object, no line number
## information is printed.
# RUN: llvm-mc --filetype=obj %t/main.s -o %t/no-dwarf.o
# RUN: llvm-nm -l %t/no-dwarf.o | FileCheck %s --check-prefix=NO-DWARF --match-full-lines --implicit-check-not={{.}}

# NO-DWARF: 0000000000001234 a absolute_symbol
# NO-DWARF-NEXT: 0000000000000000 d data_no_dwarf
# NO-DWARF-NEXT: 0000000000000000 T defined_global_function
# NO-DWARF-NEXT: 0000000000000001 t defined_local_function
# NO-DWARF-NEXT: 0000000000000000 t function_no_dwarf
# NO-DWARF-NEXT: U undef1
# NO-DWARF-NEXT: U undef2
# NO-DWARF-NEXT: U undef_no_reloc
# NO-DWARF-NEXT: 0000000000000002 t undefined_references

## Check that printing line numbers for undefined values is not attempted in
## the absence of any relocation section.
# RUN: llvm-mc --filetype=obj %t/undef-no-reloc-sections.s -o %t/undef-no-reloc-sections.o
# RUN: llvm-nm --line-numbers %t/undef-no-reloc-sections.o | FileCheck %s --check-prefix=UNDEF-NO-RELOC-SECTIONS --match-full-lines --implicit-check-not={{.}}

# UNDEF-NO-RELOC-SECTIONS: U undef

## Check that printing line numbers for undefined values does not include
## relocations for non-text sections. This is broken out of main.s to ensure
## that the data relocation for undef comes first.
# RUN: llvm-mc -g --filetype=obj %t/undef-data-reloc.s -o %t/undef-data-reloc.o
# RUN: llvm-nm --line-numbers %t/undef-data-reloc.o | FileCheck %s --check-prefix=UNDEF-DATA-RELOC --match-full-lines --implicit-check-not={{.}}

# UNDEF-DATA-RELOC: 0000000000000000 r data_reloc
# UNDEF-DATA-RELOC-NEXT: U undef

## Check that line numbers can be printed for data definitions. These are broken
## out of main.s since their DWARF cannot be generated with llvm-mc -g.
# RUN: llvm-mc -g --filetype=obj %t/data-dwarf.s -o %t/data-dwarf.o
# RUN: llvm-nm --line-numbers %t/data-dwarf.o | FileCheck %s --check-prefix=DATA-DWARF --match-full-lines --implicit-check-not={{.}}

# DATA-DWARF: 0000000000000000 D defined_data /tmp/tmp.c:1

#--- main.s
.text
.globl defined_global_function
defined_global_function:
ret

defined_local_function:
ret

absolute_symbol = 0x1234

undefined_references:
nop
.long undef1
nop
.long undef2
ret

# Note: llvm-mc -g produces no DWARF for data.
.data
data_no_dwarf:
.byte 0

.globl undef_no_reloc

# Note: llvm-mc -g does not produce DWARF for non-SHF_ALLOC sections.
.section no_alloc_text,"x",@progbits
function_no_dwarf:
ret

#--- undef-no-reloc-sections.s
.globl undef

#--- undef-data-reloc.s
.globl undef
.rodata
data_reloc:
.long undef

#--- data-dwarf.s
# char defined_data = 42
.text
.file "tmp.c"
.file 0 "/tmp" "/tmp/tmp.c" md5 0x39602a53b15a32d6a622ca86936e88d7
.file 1 "tmp.c" md5 0x39602a53b15a32d6a622ca86936e88d7
.type defined_data,@object # @defined_data
.data
.globl defined_data
defined_data:
.byte 42 # 0x2a
.size defined_data, 1

.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 1 # DW_CHILDREN_yes
.byte 37 # DW_AT_producer
.byte 37 # DW_FORM_strx1
.byte 19 # DW_AT_language
.byte 5 # DW_FORM_data2
.byte 3 # DW_AT_name
.byte 37 # DW_FORM_strx1
.byte 114 # DW_AT_str_offsets_base
.byte 23 # DW_FORM_sec_offset
.byte 16 # DW_AT_stmt_list
.byte 23 # DW_FORM_sec_offset
.byte 27 # DW_AT_comp_dir
.byte 37 # DW_FORM_strx1
.byte 115 # DW_AT_addr_base
.byte 23 # DW_FORM_sec_offset
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 2 # Abbreviation Code
.byte 52 # DW_TAG_variable
.byte 0 # DW_CHILDREN_no
.byte 3 # DW_AT_name
.byte 37 # DW_FORM_strx1
.byte 73 # DW_AT_type
.byte 19 # DW_FORM_ref4
.byte 63 # DW_AT_external
.byte 25 # DW_FORM_flag_present
.byte 58 # DW_AT_decl_file
.byte 11 # DW_FORM_data1
.byte 59 # DW_AT_decl_line
.byte 11 # DW_FORM_data1
.byte 2 # DW_AT_location
.byte 24 # DW_FORM_exprloc
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 3 # Abbreviation Code
.byte 36 # DW_TAG_base_type
.byte 0 # DW_CHILDREN_no
.byte 3 # DW_AT_name
.byte 37 # DW_FORM_strx1
.byte 62 # DW_AT_encoding
.byte 11 # DW_FORM_data1
.byte 11 # DW_AT_byte_size
.byte 11 # DW_FORM_data1
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 0 # EOM(3)
.section .debug_info,"",@progbits
.Lcu_begin0:
.long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
.Ldebug_info_start0:
.short 5 # DWARF version number
.byte 1 # DWARF Unit Type
.byte 8 # Address Size (in bytes)
.long .debug_abbrev # Offset Into Abbrev. Section
.byte 1 # Abbrev [1] 0xc:0x22 DW_TAG_compile_unit
.byte 0 # DW_AT_producer
.short 12 # DW_AT_language
.byte 1 # DW_AT_name
.long .Lstr_offsets_base0 # DW_AT_str_offsets_base
.long .Lline_table_start0 # DW_AT_stmt_list
.byte 2 # DW_AT_comp_dir
.long .Laddr_table_base0 # DW_AT_addr_base
.byte 2 # Abbrev [2] 0x1e:0xb DW_TAG_variable
.byte 3 # DW_AT_name
.long 41 # DW_AT_type
# DW_AT_external
.byte 1 # DW_AT_decl_file
.byte 1 # DW_AT_decl_line
.byte 2 # DW_AT_location
.byte 161
.byte 0
.byte 3 # Abbrev [3] 0x29:0x4 DW_TAG_base_type
.byte 4 # DW_AT_name
.byte 6 # DW_AT_encoding
.byte 1 # DW_AT_byte_size
.byte 0 # End Of Children Mark
.Ldebug_info_end0:
.section .debug_str_offsets,"",@progbits
.long 24 # Length of String Offsets Set
.short 5
.short 0
.Lstr_offsets_base0:
.section .debug_str,"MS",@progbits,1
.Linfo_string0:
.asciz "Debian clang version 14.0.6" # string offset=0
.Linfo_string1:
.asciz "/tmp/tmp.c" # string offset=28
.Linfo_string2:
.asciz "/tmp" # string offset=39
.Linfo_string3:
.asciz "defined_data" # string offset=44
.Linfo_string4:
.asciz "char" # string offset=57
.section .debug_str_offsets,"",@progbits
.long .Linfo_string0
.long .Linfo_string1
.long .Linfo_string2
.long .Linfo_string3
.long .Linfo_string4
.section .debug_addr,"",@progbits
.long .Ldebug_addr_end0-.Ldebug_addr_start0 # Length of contribution
.Ldebug_addr_start0:
.short 5 # DWARF version number
.byte 8 # Address size
.byte 0 # Segment selector size
.Laddr_table_base0:
.quad defined_data
.Ldebug_addr_end0:
.ident "Debian clang version 14.0.6"
.section ".note.GNU-stack","",@progbits
.addrsig
.section .debug_line,"",@progbits
.Lline_table_start0:
1 change: 1 addition & 0 deletions llvm/tools/llvm-nm/CMakeLists.txt
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Expand Up @@ -8,6 +8,7 @@ set(LLVM_LINK_COMPONENTS
Object
Option
Support
Symbolize
TargetParser
TextAPI
)
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2 changes: 2 additions & 0 deletions llvm/tools/llvm-nm/Opts.td
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Expand Up @@ -22,6 +22,7 @@ def export_symbols : FF<"export-symbols", "Export symbol list for all inputs">;
def extern_only : FF<"extern-only", "Show only external symbols">;
defm format : Eq<"format", "Specify output format: bsd (default), posix, sysv, darwin, just-symbols">, MetaVarName<"<format>">;
def help : FF<"help", "Display this help">;
def line_numbers : FF<"line-numbers", "Use debugging information to print symbols' filenames and line numbers">;
def no_llvm_bc : FF<"no-llvm-bc", "Disable LLVM bitcode reader">;
def no_sort : FF<"no-sort", "Show symbols in order encountered">;
def no_weak : FF<"no-weak", "Show only non-weak symbols">;
Expand Down Expand Up @@ -67,6 +68,7 @@ def : JoinedOrSeparate<["-"], "f">, HelpText<"Alias for --format">, Alias<format
def : F<"h", "Alias for --help">, Alias<help>;
def : F<"g", "Alias for --extern-only">, Alias<extern_only>;
def : F<"j", "Alias for --format=just-symbols">, Alias<format_EQ>, AliasArgs<["just-symbols"]>;
def : F<"l", "Alias for --line-numbers">, Alias<line_numbers>;
def : F<"m", "Alias for --format=darwin">, Alias<format_EQ>, AliasArgs<["darwin"]>;
def : F<"M", "Deprecated alias for --print-armap">, Alias<print_armap>, Flags<[HelpHidden]>;
def : F<"n", "Alias for --numeric-sort">, Alias<numeric_sort>;
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