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[DebugInfo] Fix emitting DWARF64 compilation units (5/19). 

The patch also adds a method to choose an appropriate DWARF form
to represent section offsets according to the version and the format
of producing debug info.

Differential Revision: https://reviews.llvm.org/D87014
This commit is contained in:
Igor Kudrin 2020-09-15 11:30:30 +07:00
parent 982b31fad2
commit 5dd1c59188
9 changed files with 93 additions and 14 deletions
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2
llvm/lib/CodeGen/AsmPrinter/DIE.cpp
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@ -502,6 +502,8 @@ unsigned DIELabel::SizeOf(const AsmPrinter *AP, dwarf::Form Form) const {
switch (Form) {
case dwarf::DW_FORM_data4:
return 4;
case dwarf::DW_FORM_data8:
return 8;
case dwarf::DW_FORM_sec_offset:
case dwarf::DW_FORM_strp:
return AP->getDwarfOffsetByteSize();

4
llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
View File

@ -289,8 +289,8 @@ public:
return DwarfUnit::getHeaderSize() + DWOIdSize;
}
unsigned getLength() {
return sizeof(uint32_t) + // Length field
getHeaderSize() + getUnitDie().getSize();
return Asm->getUnitLengthFieldByteSize() + // Length field
getHeaderSize() + getUnitDie().getSize();
}
void emitHeader(bool UseOffsets) override;

9
llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
View File

@ -3358,6 +3358,15 @@ uint16_t DwarfDebug::getDwarfVersion() const {
return Asm->OutStreamer->getContext().getDwarfVersion();
}
dwarf::Form DwarfDebug::getDwarfSectionOffsetForm() const {
if (Asm->getDwarfVersion() >= 4)
return dwarf::Form::DW_FORM_sec_offset;
assert((!Asm->isDwarf64() || (Asm->getDwarfVersion() == 3)) &&
"DWARF64 is not defined prior DWARFv3");
return Asm->isDwarf64() ? dwarf::Form::DW_FORM_data8
: dwarf::Form::DW_FORM_data4;
}
const MCSymbol *DwarfDebug::getSectionLabel(const MCSection *S) {
return SectionLabels.find(S)->second;
}

6
llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
View File

@ -729,6 +729,12 @@ public:
/// Returns the Dwarf Version.
uint16_t getDwarfVersion() const;
/// Returns a suitable DWARF form to represent a section offset, i.e.
/// * DW_FORM_sec_offset for DWARF version >= 4;
/// * DW_FORM_data8 for 64-bit DWARFv3;
/// * DW_FORM_data4 for 32-bit DWARFv3 and DWARFv2.
dwarf::Form getDwarfSectionOffsetForm() const;
/// Returns the previous CU that was being updated
const DwarfCompileUnit *getPrevCU() const { return PrevCU; }
void setPrevCU(const DwarfCompileUnit *PrevCU) { this->PrevCU = PrevCU; }

4
llvm/lib/CodeGen/AsmPrinter/DwarfFile.cpp
View File

@ -79,8 +79,8 @@ void DwarfFile::computeSizeAndOffsets() {
unsigned DwarfFile::computeSizeAndOffsetsForUnit(DwarfUnit *TheU) {
// CU-relative offset is reset to 0 here.
unsigned Offset = sizeof(int32_t) + // Length of Unit Info
TheU->getHeaderSize(); // Unit-specific headers
unsigned Offset = Asm->getUnitLengthFieldByteSize() + // Length of Unit Info
TheU->getHeaderSize(); // Unit-specific headers
// The return value here is CU-relative, after laying out
// all of the CU DIE.

11
llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
View File

@ -1695,15 +1695,15 @@ DIE *DwarfUnit::getOrCreateStaticMemberDIE(const DIDerivedType *DT) {
void DwarfUnit::emitCommonHeader(bool UseOffsets, dwarf::UnitType UT) {
// Emit size of content not including length itself
Asm->OutStreamer->AddComment("Length of Unit");
if (!DD->useSectionsAsReferences()) {
StringRef Prefix = isDwoUnit() ? "debug_info_dwo_" : "debug_info_";
MCSymbol *BeginLabel = Asm->createTempSymbol(Prefix + "start");
EndLabel = Asm->createTempSymbol(Prefix + "end");
Asm->emitLabelDifference(EndLabel, BeginLabel, 4);
Asm->emitDwarfUnitLength(EndLabel, BeginLabel, "Length of Unit");
Asm->OutStreamer->emitLabel(BeginLabel);
} else
Asm->emitInt32(getHeaderSize() + getUnitDie().getSize());
Asm->emitDwarfUnitLength(getHeaderSize() + getUnitDie().getSize(),
"Length of Unit");
Asm->OutStreamer->AddComment("DWARF version number");
unsigned Version = DD->getDwarfVersion();
@ -1759,10 +1759,7 @@ DIE::value_iterator
DwarfUnit::addSectionLabel(DIE &Die, dwarf::Attribute Attribute,
const MCSymbol *Label, const MCSymbol *Sec) {
if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
return addLabel(Die, Attribute,
DD->getDwarfVersion() >= 4 ? dwarf::DW_FORM_sec_offset
: dwarf::DW_FORM_data4,
Label);
return addLabel(Die, Attribute, DD->getDwarfSectionOffsetForm(), Label);
return addSectionDelta(Die, Attribute, Label, Sec);
}

6
llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
View File

@ -253,9 +253,9 @@ public:
/// Compute the size of a header for this unit, not including the initial
/// length field.
virtual unsigned getHeaderSize() const {
return sizeof(int16_t) + // DWARF version number
sizeof(int32_t) + // Offset Into Abbrev. Section
sizeof(int8_t) + // Pointer Size (in bytes)
return sizeof(int16_t) + // DWARF version number
Asm->getDwarfOffsetByteSize() + // Offset Into Abbrev. Section
sizeof(int8_t) + // Pointer Size (in bytes)
(DD->getDwarfVersion() >= 5 ? sizeof(int8_t)
: 0); // DWARF v5 unit type
}

63
llvm/test/DebugInfo/X86/debug-info-dwarf64.ll Normal file
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@ -0,0 +1,63 @@
; This checks that .debug_info can be generated in the DWARF64 format.
; RUN: llc -mtriple=x86_64 -dwarf-version=3 -dwarf64 -filetype=obj %s -o %t3
; RUN: llvm-dwarfdump -debug-abbrev -debug-info -v %t3 | \
; RUN: FileCheck %s --check-prefixes=CHECK,DWARFv3
; RUN: llc -mtriple=x86_64 -dwarf-version=4 -dwarf64 -filetype=obj %s -o %t4
; RUN: llvm-dwarfdump -debug-abbrev -debug-info -v %t4 | \
; RUN: FileCheck %s --check-prefixes=CHECK,DWARFv4
; CHECK: .debug_abbrev contents:
; CHECK: [1] DW_TAG_compile_unit DW_CHILDREN_yes
; CHECK-NEXT: DW_AT_producer DW_FORM_strp
; CHECK-NEXT: DW_AT_language DW_FORM_data2
; CHECK-NEXT: DW_AT_name DW_FORM_strp
; DWARFv3-NEXT: DW_AT_stmt_list DW_FORM_data8
; DWARFv4-NEXT: DW_AT_stmt_list DW_FORM_sec_offset
; CHECK-NEXT: DW_AT_comp_dir DW_FORM_strp
; CHECK: [2] DW_TAG_variable DW_CHILDREN_no
; CHECK-NEXT: DW_AT_name DW_FORM_strp
; CHECK-NEXT: DW_AT_type DW_FORM_ref4
; CHECK: [3] DW_TAG_base_type DW_CHILDREN_no
; CHECK-NEXT: DW_AT_name DW_FORM_strp
; CHECK: .debug_info contents:
; CHECK: Compile Unit: length = 0x{{([[:xdigit:]]{16})}}, format = DWARF64,
; CHECK: DW_TAG_compile_unit [1] *
; CHECK-NEXT: DW_AT_producer [DW_FORM_strp] ( .debug_str[0x{{([[:xdigit:]]{16})}}] = "clang version 12.0.0")
; CHECK-NEXT: DW_AT_language [DW_FORM_data2] (DW_LANG_C99)
; CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x{{([[:xdigit:]]{16})}}] = "foo.c")
; DWARFv3-NEXT: DW_AT_stmt_list [DW_FORM_data8] (0x0000000000000000)
; DWARFv4-NEXT: DW_AT_stmt_list [DW_FORM_sec_offset] (0x0000000000000000)
; CHECK-NEXT: DW_AT_comp_dir [DW_FORM_strp] ( .debug_str[0x{{([[:xdigit:]]{16})}}] = "/tmp")
; CHECK: DW_TAG_variable [2]
; CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x{{([[:xdigit:]]{16})}}] = "foo")
; CHECK-NEXT: DW_AT_type [DW_FORM_ref4] (cu + {{.+}} => {{.+}} "int")
; CHECK: DW_TAG_base_type [3]
; CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x{{([[:xdigit:]]{16})}}] = "int")
; IR generated and reduced from:
; $ cat foo.c
; int foo;
; $ clang -g -S -emit-llvm foo.c -o foo.ll
target triple = "x86_64-unknown-linux-gnu"
@foo = dso_local global i32 0, align 4, !dbg !0
!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!7, !8, !9}
!llvm.ident = !{!10}
!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
!1 = distinct !DIGlobalVariable(name: "foo", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true)
!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 12.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, splitDebugInlining: false, nameTableKind: None)
!3 = !DIFile(filename: "foo.c", directory: "/tmp")
!4 = !{}
!5 = !{!0}
!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!7 = !{i32 7, !"Dwarf Version", i32 4}
!8 = !{i32 2, !"Debug Info Version", i32 3}
!9 = !{i32 1, !"wchar_size", i32 4}
!10 = !{!"clang version 12.0.0"}

2
llvm/unittests/CodeGen/DIETest.cpp
View File

@ -117,10 +117,12 @@ INSTANTIATE_TEST_CASE_P(
DIETestParams, DIELabelFixture,
testing::Values(
DIETestParams{4, dwarf::DWARF32, dwarf::DW_FORM_data4, 4u},
DIETestParams{4, dwarf::DWARF32, dwarf::DW_FORM_data8, 8u},
DIETestParams{4, dwarf::DWARF32, dwarf::DW_FORM_sec_offset, 4u},
DIETestParams{4, dwarf::DWARF32, dwarf::DW_FORM_strp, 4u},
DIETestParams{4, dwarf::DWARF32, dwarf::DW_FORM_addr, 8u},
DIETestParams{4, dwarf::DWARF64, dwarf::DW_FORM_data4, 4u},
DIETestParams{4, dwarf::DWARF64, dwarf::DW_FORM_data8, 8u},
DIETestParams{4, dwarf::DWARF64, dwarf::DW_FORM_sec_offset, 8u},
DIETestParams{4, dwarf::DWARF64, dwarf::DW_FORM_strp, 8u},
DIETestParams{4, dwarf::DWARF64, dwarf::DW_FORM_addr, 8u}), );