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[BOLT] Fix DWARF4/5 file index handling in debug info functions #151401

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Merged
merged 5 commits into from
Aug 29, 2025
Merged

[BOLT] Fix DWARF4/5 file index handling in debug info functions #151401

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bf6a278
Use getFileNameEntry for retrieving FileNameEntry DWARF version agnos…
grigorypas Jul 30, 2025
18c8d04
Drop changes to perf_test.lds
grigorypas Aug 18, 2025
89d18e2
Add tests that trigger DWARF4 vs DWARF5 bug explicitly
grigorypas Aug 20, 2025
2327070
Convert tests to assembly
grigorypas Aug 27, 2025
9e6f437
Fix typo in comment
grigorypas Aug 29, 2025
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18 changes: 7 additions & 11 deletions bolt/lib/Core/BinaryContext.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1568,23 +1568,19 @@ unsigned BinaryContext::addDebugFilenameToUnit(const uint32_t DestCUID,
DWARFCompileUnit *SrcUnit = DwCtx->getCompileUnitForOffset(SrcCUID);
const DWARFDebugLine::LineTable *LineTable =
DwCtx->getLineTableForUnit(SrcUnit);
const std::vector<DWARFDebugLine::FileNameEntry> &FileNames =
LineTable->Prologue.FileNames;
// Dir indexes start at 1, as DWARF file numbers, and a dir index 0
const DWARFDebugLine::FileNameEntry &FileNameEntry =
LineTable->Prologue.getFileNameEntry(FileIndex);
// Dir indexes start at 1 and a dir index 0
// means empty dir.
assert(FileIndex > 0 && FileIndex <= FileNames.size() &&
"FileIndex out of range for the compilation unit.");
StringRef Dir = "";
if (FileNames[FileIndex - 1].DirIdx != 0) {
if (FileNameEntry.DirIdx != 0) {
if (std::optional<const char *> DirName = dwarf::toString(
LineTable->Prologue
.IncludeDirectories[FileNames[FileIndex - 1].DirIdx - 1])) {
LineTable->Prologue.IncludeDirectories[FileNameEntry.DirIdx - 1])) {
Dir = *DirName;
}
}
StringRef FileName = "";
if (std::optional<const char *> FName =
dwarf::toString(FileNames[FileIndex - 1].Name))
if (std::optional<const char *> FName = dwarf::toString(FileNameEntry.Name))
FileName = *FName;
assert(FileName != "");
DWARFCompileUnit *DstUnit = DwCtx->getCompileUnitForOffset(DestCUID);
Expand Down Expand Up @@ -1925,7 +1921,7 @@ static void printDebugInfo(raw_ostream &OS, const MCInst &Instruction,
const DWARFDebugLine::Row &Row = LineTable->Rows[RowRef.RowIndex - 1];
StringRef FileName = "";
if (std::optional<const char *> FName =
dwarf::toString(LineTable->Prologue.FileNames[Row.File - 1].Name))
dwarf::toString(LineTable->Prologue.getFileNameEntry(Row.File).Name))
FileName = *FName;
OS << " # debug line " << FileName << ":" << Row.Line;
if (Row.Column)
Expand Down
148 changes: 148 additions & 0 deletions bolt/test/X86/dwarf5-debug-line-print.s
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Original file line number Diff line number Diff line change
@@ -0,0 +1,148 @@
# REQUIRES: system-linux

## Check that BOLT correctly prints debug line comments for DWARF-5.


# RUN: llvm-mc -dwarf-version=5 -filetype=obj -triple x86_64-unknown-linux %s -o %t1.o
# RUN: %clang %cflags -dwarf-5 %t1.o -o %t.exe -Wl,-q
# RUN: llvm-bolt %t.exe --update-debug-sections --print-debug-info \
# RUN: --print-after-lowering -o %t.bolt | FileCheck %s

# CHECK: xorq %rdi, %rdi # debug line main.c:2:5

# __attribute__((naked)) void _start() {
# __asm__(
# "xor %rdi, %rdi\n" // exit code 0
# "mov $60, %rax\n" // syscall number for exit
# "syscall\n"
# );
# }

.file "main.c"
.text
.globl _start # -- Begin function _start
.p2align 4
.type _start,@function
_start: # @_start
.Lfunc_begin0:
.file 0 "/home/gpastukhov/tmp2" "main.c" md5 0x94c0e54a615c2a21415ddb904991abd8
.cfi_startproc
# %bb.0:
.loc 0 2 5 prologue_end # main.c:2:5
#APP
xorq %rdi, %rdi
movq $60, %rax
syscall

#NO_APP
.Ltmp0:
.Lfunc_end0:
.size _start, .Lfunc_end0-_start
.cfi_endproc
# -- End function
.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 17 # DW_AT_low_pc
.byte 27 # DW_FORM_addrx
.byte 18 # DW_AT_high_pc
.byte 6 # DW_FORM_data4
.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 46 # DW_TAG_subprogram
.byte 0 # DW_CHILDREN_no
.byte 17 # DW_AT_low_pc
.byte 27 # DW_FORM_addrx
.byte 18 # DW_AT_high_pc
.byte 6 # DW_FORM_data4
.byte 64 # DW_AT_frame_base
.byte 24 # DW_FORM_exprloc
.byte 3 # DW_AT_name
.byte 37 # DW_FORM_strx1
.byte 58 # DW_AT_decl_file
.byte 11 # DW_FORM_data1
.byte 59 # DW_AT_decl_line
.byte 11 # DW_FORM_data1
.byte 63 # DW_AT_external
.byte 25 # DW_FORM_flag_present
.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:0x23 DW_TAG_compile_unit
.byte 0 # DW_AT_producer
.short 29 # 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
.byte 0 # DW_AT_low_pc
.long .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
.long .Laddr_table_base0 # DW_AT_addr_base
.byte 2 # Abbrev [2] 0x23:0xb DW_TAG_subprogram
.byte 0 # DW_AT_low_pc
.long .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
.byte 1 # DW_AT_frame_base
.byte 87
.byte 3 # DW_AT_name
.byte 0 # DW_AT_decl_file
.byte 1 # DW_AT_decl_line
# DW_AT_external
.byte 0 # End Of Children Mark
.Ldebug_info_end0:
.section .debug_str_offsets,"",@progbits
.long 20 # Length of String Offsets Set
.short 5
.short 0
.Lstr_offsets_base0:
.section .debug_str,"MS",@progbits,1
.Linfo_string0:
.asciz "clang version 20.1.8 (CentOS 20.1.8-1.el9)" # string offset=0
.Linfo_string1:
.asciz "main.c" # string offset=43
.Linfo_string2:
.asciz "/home/gpastukhov/tmp2" # string offset=50
.Linfo_string3:
.asciz "_start" # string offset=72
.section .debug_str_offsets,"",@progbits
.long .Linfo_string0
.long .Linfo_string1
.long .Linfo_string2
.long .Linfo_string3
.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 .Lfunc_begin0
.Ldebug_addr_end0:
.ident "clang version 20.1.8 (CentOS 20.1.8-1.el9)"
.section ".note.GNU-stack","",@progbits
.addrsig
.section .debug_line,"",@progbits
.Lline_table_start0:
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