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llvm-symbolizer: Fix "start file" to work with Split DWARF
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A followup to the feature added in
69da27c that added the optional "start
file name" to match "start line" - but this didn't work with Split DWARF
because of the need for the decl file number resolution code to refer
back to the skeleton unit to find its .debug_line contribution. So this
patch adds the necessary infrastructure to track the skeleton unit
corresponding to a split full unit for the purpose of this lookup.
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@dwblaikie
dwblaikie committed Jul 10, 2021
1 parent 882ee7f commit 04c203e
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Showing 4 changed files with 229 additions and 4 deletions.
7 changes: 7 additions & 0 deletions llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h
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Original file line number Diff line number Diff line change
Expand Up @@ -218,6 +218,7 @@ class DWARFUnit {
StringRef StringSection;
const DWARFSection &StringOffsetSection;
const DWARFSection *AddrOffsetSection;
DWARFUnit *SU;
Optional<uint64_t> AddrOffsetSectionBase;
bool isLittleEndian;
bool IsDWO;
Expand Down Expand Up @@ -301,6 +302,12 @@ class DWARFUnit {
return StringOffsetSection;
}

void setSkeletonUnit(DWARFUnit *SU) { this->SU = SU; }
// Returns itself if not using Split DWARF, or if the unit is a skeleton unit
// - otherwise returns the split full unit's corresponding skeleton, if
// available.
DWARFUnit *getLinkedUnit() { return IsDWO ? SU : this; }

void setAddrOffsetSection(const DWARFSection *AOS, uint64_t Base) {
AddrOffsetSection = AOS;
AddrOffsetSectionBase = Base;
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13 changes: 9 additions & 4 deletions llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -571,11 +571,16 @@ uint64_t DWARFDie::getDeclLine() const {

std::string
DWARFDie::getDeclFile(DILineInfoSpecifier::FileLineInfoKind Kind) const {
auto D = getAttributeValueAsReferencedDie(DW_AT_abstract_origin);
if (!D)
D = *this;
std::string FileName;
if (auto DeclFile = toUnsigned(findRecursively(DW_AT_decl_file))) {
if (const auto *LT = U->getContext().getLineTableForUnit(U)) {
LT->getFileNameByIndex(*DeclFile, U->getCompilationDir(), Kind, FileName);
}
if (auto DeclFile = toUnsigned(D.find(DW_AT_decl_file))) {
if (const auto *LineTable =
getDwarfUnit()->getContext().getLineTableForUnit(
D.getDwarfUnit()->getLinkedUnit()))
LineTable->getFileNameByIndex(
*DeclFile, D.getDwarfUnit()->getCompilationDir(), Kind, FileName);
}
return FileName;
}
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2 changes: 2 additions & 0 deletions llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -388,6 +388,7 @@ void DWARFUnit::clear() {
RangeSectionBase = 0;
LocSectionBase = 0;
AddrOffsetSectionBase = None;
SU = nullptr;
clearDIEs(false);
DWO.reset();
}
Expand Down Expand Up @@ -586,6 +587,7 @@ bool DWARFUnit::parseDWO() {
if (!DWOCU)
return false;
DWO = std::shared_ptr<DWARFCompileUnit>(std::move(DWOContext), DWOCU);
DWO->setSkeletonUnit(this);
// Share .debug_addr and .debug_ranges section with compile unit in .dwo
if (AddrOffsetSectionBase)
DWO->setAddrOffsetSection(AddrOffsetSection, *AddrOffsetSectionBase);
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211 changes: 211 additions & 0 deletions llvm/test/DebugInfo/X86/symbolize_function_start.s
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Original file line number Diff line number Diff line change
@@ -0,0 +1,211 @@
# RUN: rm -rf %t
# RUN: mkdir %t
# RUN: llvm-mc -filetype=obj -triple=x86_64 -dwarf-version=4 %s -o %t/test.o
# RUN: cd %t
# RUN: llvm-symbolizer -verbose 0x0 -obj=test.o | FileCheck --check-prefix=SYM %s
# RUN: llvm-dwarfdump -lookup=0x1 test.o | FileCheck --check-prefix=LOOKUP %s

# SYM: Filename: ./././test.h
# SYM: Function start filename: ./test.cpp

# LOOKUP: Line info: line 0, column 0, start file 'test.cpp', start line 1


.text
.file "test.cpp"
.globl _Z2f1v # -- Begin function _Z2f1v
.p2align 4, 0x90
.type _Z2f1v,@function
_Z2f1v: # @_Z2f1v
.Lfunc_begin0:
.file 1 "." "test.cpp"
.loc 1 1 0 # test.cpp:1:0
.cfi_startproc
# %bb.0: # %entry
.file 2 "." "./test.h"
.loc 2 1 1 prologue_end # ./test.h:1:1
xorl %eax, %eax
retq
.Ltmp0:
.Lfunc_end0:
.size _Z2f1v, .Lfunc_end0-_Z2f1v
.cfi_endproc
# -- End function
.section .debug_abbrev,"",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 0 # DW_CHILDREN_no
.byte 16 # DW_AT_stmt_list
.byte 23 # DW_FORM_sec_offset
.byte 27 # DW_AT_comp_dir
.byte 14 # DW_FORM_strp
.ascii "\264B" # DW_AT_GNU_pubnames
.byte 25 # DW_FORM_flag_present
.ascii "\260B" # DW_AT_GNU_dwo_name
.byte 14 # DW_FORM_strp
.ascii "\261B" # DW_AT_GNU_dwo_id
.byte 7 # DW_FORM_data8
.byte 17 # DW_AT_low_pc
.byte 1 # DW_FORM_addr
.byte 18 # DW_AT_high_pc
.byte 6 # DW_FORM_data4
.ascii "\263B" # DW_AT_GNU_addr_base
.byte 23 # DW_FORM_sec_offset
.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 4 # DWARF version number
.long .debug_abbrev # Offset Into Abbrev. Section
.byte 8 # Address Size (in bytes)
.byte 1 # Abbrev [1] 0xb:0x25 DW_TAG_compile_unit
.long .Lline_table_start0 # DW_AT_stmt_list
.long .Lskel_string0 # DW_AT_comp_dir
# DW_AT_GNU_pubnames
.long .Lskel_string1 # DW_AT_GNU_dwo_name
.quad 7198491773836599109 # DW_AT_GNU_dwo_id
.quad .Lfunc_begin0 # DW_AT_low_pc
.long .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
.long .Laddr_table_base0 # DW_AT_GNU_addr_base
.Ldebug_info_end0:
.section .debug_str,"MS",@progbits,1
.Lskel_string0:
.asciz "." # string offset=0
.Lskel_string1:
.asciz "test.o" # string offset=2
.section .debug_str.dwo,"eMS",@progbits,1
.Linfo_string0:
.asciz "_Z2f1v" # string offset=0
.Linfo_string1:
.asciz "f1" # string offset=7
.Linfo_string2:
.asciz "int" # string offset=10
.Linfo_string3:
.asciz "clang version 13.0.0 (git@github.com:llvm/llvm-project.git 882ee7fbd6fc989fba53f3d9672440771feb80f5)" # string offset=14
.Linfo_string4:
.asciz "test.cpp" # string offset=115
.Linfo_string5:
.asciz "test.o" # string offset=124
.section .debug_str_offsets.dwo,"e",@progbits
.long 0
.long 7
.long 10
.long 14
.long 115
.long 124
.section .debug_info.dwo,"e",@progbits
.long .Ldebug_info_dwo_end0-.Ldebug_info_dwo_start0 # Length of Unit
.Ldebug_info_dwo_start0:
.short 4 # DWARF version number
.long 0 # Offset Into Abbrev. Section
.byte 8 # Address Size (in bytes)
.byte 1 # Abbrev [1] 0xb:0x23 DW_TAG_compile_unit
.byte 3 # DW_AT_producer
.short 33 # DW_AT_language
.byte 4 # DW_AT_name
.byte 5 # DW_AT_GNU_dwo_name
.quad 7198491773836599109 # DW_AT_GNU_dwo_id
.byte 2 # Abbrev [2] 0x19:0x10 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
# DW_AT_GNU_all_call_sites
.byte 0 # DW_AT_linkage_name
.byte 1 # DW_AT_name
.byte 1 # DW_AT_decl_file
.byte 1 # DW_AT_decl_line
.long 41 # DW_AT_type
# DW_AT_external
.byte 3 # Abbrev [3] 0x29:0x4 DW_TAG_base_type
.byte 2 # DW_AT_name
.byte 5 # DW_AT_encoding
.byte 4 # DW_AT_byte_size
.byte 0 # End Of Children Mark
.Ldebug_info_dwo_end0:
.section .debug_abbrev.dwo,"e",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 1 # DW_CHILDREN_yes
.byte 37 # DW_AT_producer
.ascii "\202>" # DW_FORM_GNU_str_index
.byte 19 # DW_AT_language
.byte 5 # DW_FORM_data2
.byte 3 # DW_AT_name
.ascii "\202>" # DW_FORM_GNU_str_index
.ascii "\260B" # DW_AT_GNU_dwo_name
.ascii "\202>" # DW_FORM_GNU_str_index
.ascii "\261B" # DW_AT_GNU_dwo_id
.byte 7 # DW_FORM_data8
.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
.ascii "\201>" # DW_FORM_GNU_addr_index
.byte 18 # DW_AT_high_pc
.byte 6 # DW_FORM_data4
.byte 64 # DW_AT_frame_base
.byte 24 # DW_FORM_exprloc
.ascii "\227B" # DW_AT_GNU_all_call_sites
.byte 25 # DW_FORM_flag_present
.byte 110 # DW_AT_linkage_name
.ascii "\202>" # DW_FORM_GNU_str_index
.byte 3 # DW_AT_name
.ascii "\202>" # DW_FORM_GNU_str_index
.byte 58 # DW_AT_decl_file
.byte 11 # DW_FORM_data1
.byte 59 # DW_AT_decl_line
.byte 11 # DW_FORM_data1
.byte 73 # DW_AT_type
.byte 19 # DW_FORM_ref4
.byte 63 # DW_AT_external
.byte 25 # DW_FORM_flag_present
.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
.ascii "\202>" # DW_FORM_GNU_str_index
.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_addr,"",@progbits
.Laddr_table_base0:
.quad .Lfunc_begin0
.section .debug_gnu_pubnames,"",@progbits
.long .LpubNames_end0-.LpubNames_start0 # Length of Public Names Info
.LpubNames_start0:
.short 2 # DWARF Version
.long .Lcu_begin0 # Offset of Compilation Unit Info
.long 48 # Compilation Unit Length
.long 25 # DIE offset
.byte 48 # Attributes: FUNCTION, EXTERNAL
.asciz "f1" # External Name
.long 0 # End Mark
.LpubNames_end0:
.section .debug_gnu_pubtypes,"",@progbits
.long .LpubTypes_end0-.LpubTypes_start0 # Length of Public Types Info
.LpubTypes_start0:
.short 2 # DWARF Version
.long .Lcu_begin0 # Offset of Compilation Unit Info
.long 48 # Compilation Unit Length
.long 41 # DIE offset
.byte 144 # Attributes: TYPE, STATIC
.asciz "int" # External Name
.long 0 # End Mark
.LpubTypes_end0:
.ident "clang version 13.0.0 (git@github.com:llvm/llvm-project.git 882ee7fbd6fc989fba53f3d9672440771feb80f5)"
.section ".note.GNU-stack","",@progbits
.addrsig
.section .debug_line,"",@progbits
.Lline_table_start0:

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