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[llvm-dwp] Adding support for v5 index writing
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This patch adds general support for DWARFv5 index writing.
In particular, this means only allowing inputs with one version,
either DWARFv5 or DWARFv4.

This patch adds the .debug_macro section as an example,
but the DWARFv5 type support and loc and rangelists are still
missing (and upcoming).

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D102315
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@ktran @dwblaikie
ktran authored and dwblaikie committed Jun 2, 2021
1 parent fa51c5a commit 6e2d304
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Showing 5 changed files with 139 additions and 53 deletions.
55 changes: 55 additions & 0 deletions llvm/test/tools/llvm-dwp/X86/debug_macro_v5.s
View file
@@ -0,0 +1,55 @@
# This test checks the support for writing macro sections and their index (v5).

# RUN: llvm-mc -triple x86_64-unknown-linux --filetype=obj --split-dwarf-file=%t.dwo -dwarf-version=5 %s -o %t.o
# RUN: llvm-dwp %t.dwo -o %t.dwp 2>&1
# RUN: llvm-dwarfdump -debug-macro -debug-cu-index %t.dwp | FileCheck %s

# CHECK-DAG: .debug_macro.dwo contents:
# CHECK: macro header: version = 0x0005, flags = 0x00, format = DWARF32
# CHECK-NEXT: DW_MACRO_start_file - lineno: 0 filenum: 0
# CHECK-NEXT: DW_MACRO_define_strx - lineno: 1 macro: x 5
# CHECK-NEXT: DW_MACRO_end_file

# CHECK-DAG: .debug_cu_index contents:
# CHECK-NEXT: version = 5, units = 1, slots = 2
# CHECK: Index Signature INFO ABBREV STR_OFFSETS MACRO
# CHECK: 1 0x0000000000000000 [0x00000000, 0x00000019) [0x00000000, 0x00000008) [0x00000000, 0x0000000c) [0x00000000, 0x0000000b)

.section .debug_info.dwo,"e",@progbits
.long .Ldebug_info_dwo_end0-.Ldebug_info_dwo_start0 # Length of Unit
.Ldebug_info_dwo_start0:
.short 5 # DWARF version number
.byte 5 # DWARF Unit Type (DW_UT_split_compile)
.byte 8 # Address Size (in bytes)
.long 0 # Offset Into Abbrev. Section
.quad 0
.byte 1 # Abbrev [1] 0x14:0x5 DW_TAG_compile_unit
.long 0 # DW_AT_macros
.Ldebug_info_dwo_end0:
.section .debug_macro.dwo,"e",@progbits
.short 5 # Macro information version
.byte 0 # Flags: 32 bit
.byte 3 # DW_MACRO_start_file
.byte 0 # Line Number
.byte 0 # File Number
.byte 11 # DW_MACRO_define_strx
.byte 1 # Line Number
.byte 0 # Macro String
.byte 4 # DW_MACRO_end_file
.byte 0 # End Of Macro List Mark
.section .debug_abbrev.dwo,"e",@progbits
.byte 1 # Abbreviation Code
.byte 17 # DW_TAG_compile_unit
.byte 0 # DW_CHILDREN_no
.byte 121 # DW_AT_macros
.byte 23 # DW_FORM_sec_offset
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 0 # EOM(3)
.section .debug_str.dwo,"eMS",@progbits,1
.asciz "x 5" # string offset=0
.section .debug_str_offsets.dwo,"e",@progbits
.long 8 # Length of String Offsets Set
.short 5
.short 0
.long 0
7 changes: 4 additions & 3 deletions ...vm-dwp/X86/unsupported_cu_index_version.s → ...-dwp/X86/incompatible_cu_index_versions.s
View file
@@ -1,19 +1,20 @@
# RUN: llvm-mc -triple x86_64-unknown-linux %s -filetype=obj -o %t.dwp
# RUN: not llvm-dwp %t.dwp -o %t 2>&1 | FileCheck %s

# CHECK: error: unsupported cu_index version: 5 (only version 2 is supported)
# CHECK: error: incompatible cu_index versions, found 2 and expecting 5
.section .debug_info.dwo, "e", @progbits
.long .Ldebug_info_dwo_end0-.Ldebug_info_dwo_start0 # Length of Unit
.Ldebug_info_dwo_start0:
.short 5 # DWARF version number
.byte 5 # DWARF Unit type
.byte 5 # DWARF Unit type (DW_UT_split_compile)
.byte 8 # Address Size (in bytes)
.long 0 # Offset Into Abbrev. Section
.quad -346972125991005518
.byte 0 # Abbrev [9] 0xb:0x37 DW_TAG_compile_unit
.Ldebug_info_dwo_end0:
.section .debug_cu_index, "", @progbits
## Header:
.short 5 # Version
.short 2 # Version
.space 2 # Padding
.long 2 # Section count
.long 1 # Unit count
Expand Down
2 changes: 1 addition & 1 deletion llvm/test/tools/llvm-dwp/X86/info-v5.s
View file
Expand Up @@ -9,7 +9,7 @@
#CHECK: 0x00000000: Compile Unit: length = 0x00000050, format = DWARF32, version = 0x0005, unit_type = DW_UT_split_compile, abbr_offset = 0x0000, addr_size = 0x08, DWO_id = [[DWOID:.*]] (next unit at 0x00000054)

# CHECK-DAG: .debug_cu_index contents:
# CHECK: version = 2, units = 1, slots = 2
# CHECK: version = 5, units = 1, slots = 2
# CHECK: Index Signature INFO ABBREV
# CHECK: 1 [[DWOID]] [0x00000000, 0x00000054) [0x00000000, 0x0000002a)

Expand Down
2 changes: 1 addition & 1 deletion llvm/test/tools/llvm-dwp/X86/unsupported_tu_index_version.s
View file
Expand Up @@ -5,7 +5,7 @@
## of version 2 and a TU index of version 5. A valid TU is not required, but
## the .debug_types.dwo section should not be empty.

# CHECK: error: unsupported tu_index version: 5 (only version 2 is supported)
# CHECK: error: expected index version 2, but got: 5

.section .debug_abbrev.dwo, "e", @progbits
.LAbbrevBegin:
Expand Down
126 changes: 78 additions & 48 deletions llvm/tools/llvm-dwp/llvm-dwp.cpp
View file
Expand Up @@ -174,7 +174,7 @@ static void writeStringsAndOffsets(MCStreamer &Out, DWPStringPool &Strings,
MCSection *StrOffsetSection,
StringRef CurStrSection,
StringRef CurStrOffsetSection,
const InfoSectionUnitHeader &Header) {
uint16_t Version) {
// Could possibly produce an error or warning if one of these was non-null but
// the other was null.
if (CurStrSection.empty() || CurStrOffsetSection.empty())
Expand All @@ -195,7 +195,7 @@ static void writeStringsAndOffsets(MCStreamer &Out, DWPStringPool &Strings,

Out.SwitchSection(StrOffsetSection);

uint64_t HeaderSize = debugStrOffsetsHeaderSize(Data, Header.Version);
uint64_t HeaderSize = debugStrOffsetsHeaderSize(Data, Version);
uint64_t Offset = 0;
uint64_t Size = CurStrOffsetSection.size();
// FIXME: This can be caused by bad input and should be handled as such.
Expand Down Expand Up @@ -340,10 +340,10 @@ static bool isSupportedSectionKind(DWARFSectionKind Kind) {

// Convert an internal section identifier into the index to use with
// UnitIndexEntry::Contributions.
static unsigned getContributionIndex(DWARFSectionKind Kind) {
// Assuming the pre-standard DWP format.
assert(serializeSectionKind(Kind, 2) >= DW_SECT_INFO);
return serializeSectionKind(Kind, 2) - DW_SECT_INFO;
static unsigned getContributionIndex(DWARFSectionKind Kind,
uint32_t IndexVersion) {
assert(serializeSectionKind(Kind, IndexVersion) >= DW_SECT_INFO);
return serializeSectionKind(Kind, IndexVersion) - DW_SECT_INFO;
}

// Convert a UnitIndexEntry::Contributions index to the corresponding on-disk
Expand Down Expand Up @@ -379,12 +379,14 @@ static void addAllTypesFromDWP(
for (auto Kind : TUIndex.getColumnKinds()) {
if (!isSupportedSectionKind(Kind))
continue;
auto &C = Entry.Contributions[getContributionIndex(Kind)];
auto &C =
Entry.Contributions[getContributionIndex(Kind, TUIndex.getVersion())];
C.Offset += I->Offset;
C.Length = I->Length;
++I;
}
unsigned TypesIndex = getContributionIndex(DW_SECT_EXT_TYPES);
unsigned TypesIndex =
getContributionIndex(DW_SECT_EXT_TYPES, TUIndex.getVersion());
auto &C = Entry.Contributions[TypesIndex];
Out.emitBytes(Types.substr(
C.Offset - TUEntry.Contributions[TypesIndex].Offset, C.Length));
Expand All @@ -406,7 +408,7 @@ static void addAllTypes(MCStreamer &Out,
UnitIndexEntry Entry = CUEntry;
// Zero out the debug_info contribution
Entry.Contributions[0] = {};
auto &C = Entry.Contributions[getContributionIndex(DW_SECT_EXT_TYPES)];
auto &C = Entry.Contributions[getContributionIndex(DW_SECT_EXT_TYPES, 2)];
C.Offset = TypesOffset;
auto PrevOffset = Offset;
// Length of the unit, including the 4 byte length field.
Expand Down Expand Up @@ -438,10 +440,10 @@ writeIndexTable(MCStreamer &Out, ArrayRef<unsigned> ContributionOffsets,
Out.emitIntValue(E.second.Contributions[i].*Field, 4);
}

static void
writeIndex(MCStreamer &Out, MCSection *Section,
ArrayRef<unsigned> ContributionOffsets,
const MapVector<uint64_t, UnitIndexEntry> &IndexEntries) {
static void writeIndex(MCStreamer &Out, MCSection *Section,
ArrayRef<unsigned> ContributionOffsets,
const MapVector<uint64_t, UnitIndexEntry> &IndexEntries,
uint32_t IndexVersion) {
if (IndexEntries.empty())
return;

Expand All @@ -467,7 +469,7 @@ writeIndex(MCStreamer &Out, MCSection *Section,
}

Out.SwitchSection(Section);
Out.emitIntValue(2, 4); // Version
Out.emitIntValue(IndexVersion, 4); // Version
Out.emitIntValue(Columns, 4); // Columns
Out.emitIntValue(IndexEntries.size(), 4); // Num Units
Out.emitIntValue(Buckets.size(), 4); // Num Buckets
Expand Down Expand Up @@ -551,7 +553,8 @@ static Error handleSection(
StringRef &CurStrSection, StringRef &CurStrOffsetSection,
std::vector<StringRef> &CurTypesSection,
std::vector<StringRef> &CurInfoSection, StringRef &AbbrevSection,
StringRef &CurCUIndexSection, StringRef &CurTUIndexSection) {
StringRef &CurCUIndexSection, StringRef &CurTUIndexSection,
std::vector<std::pair<DWARFSectionKind, uint32_t>> &SectionLength) {
if (Section.isBSS())
return Error::success();

Expand All @@ -578,11 +581,8 @@ static Error handleSection(
return Error::success();

if (DWARFSectionKind Kind = SectionPair->second.second) {
auto Index = getContributionIndex(Kind);
if (Kind != DW_SECT_EXT_TYPES && Kind != DW_SECT_INFO) {
CurEntry.Contributions[Index].Offset = ContributionOffsets[Index];
ContributionOffsets[Index] +=
(CurEntry.Contributions[Index].Length = Contents.size());
SectionLength.push_back(std::make_pair(Kind, Contents.size()));
}

if (Kind == DW_SECT_ABBREV) {
Expand Down Expand Up @@ -664,6 +664,7 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
{"debug_str.dwo", {StrSection, static_cast<DWARFSectionKind>(0)}},
{"debug_loc.dwo", {MCOFI.getDwarfLocDWOSection(), DW_SECT_EXT_LOC}},
{"debug_line.dwo", {MCOFI.getDwarfLineDWOSection(), DW_SECT_LINE}},
{"debug_macro.dwo", {MCOFI.getDwarfMacroDWOSection(), DW_SECT_MACRO}},
{"debug_abbrev.dwo", {MCOFI.getDwarfAbbrevDWOSection(), DW_SECT_ABBREV}},
{"debug_cu_index", {CUIndexSection, static_cast<DWARFSectionKind>(0)}},
{"debug_tu_index", {TUIndexSection, static_cast<DWARFSectionKind>(0)}}};
Expand All @@ -672,6 +673,8 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
MapVector<uint64_t, UnitIndexEntry> TypeIndexEntries;

uint32_t ContributionOffsets[8] = {};
uint16_t Version = 0;
uint32_t IndexVersion = 0;

DWPStringPool Strings(Out, StrSection);

Expand All @@ -698,14 +701,19 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
StringRef CurCUIndexSection;
StringRef CurTUIndexSection;

// This maps each section contained in this file to its length.
// This information is later on used to calculate the contributions,
// i.e. offset and length, of each compile/type unit to a section.
std::vector<std::pair<DWARFSectionKind, uint32_t>> SectionLength;

for (const auto &Section : Obj.sections())
if (auto Err = handleSection(
KnownSections, StrSection, StrOffsetSection, TypesSection,
CUIndexSection, TUIndexSection, InfoSection, Section, Out,
UncompressedSections, ContributionOffsets, CurEntry,
CurStrSection, CurStrOffsetSection, CurTypesSection,
CurInfoSection, AbbrevSection, CurCUIndexSection,
CurTUIndexSection))
CurTUIndexSection, SectionLength))
return Err;

if (CurInfoSection.empty())
Expand All @@ -717,11 +725,25 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
return HeaderOrErr.takeError();
InfoSectionUnitHeader &Header = *HeaderOrErr;

if (Version == 0) {
Version = Header.Version;
IndexVersion = Version < 5 ? 2 : 5;
} else if (Version != Header.Version) {
return make_error<DWPError>("incompatible DWARF compile unit versions.");
}

writeStringsAndOffsets(Out, Strings, StrOffsetSection, CurStrSection,
CurStrOffsetSection, Header);
CurStrOffsetSection, Header.Version);

for (auto Pair : SectionLength) {
auto Index = getContributionIndex(Pair.first, IndexVersion);
CurEntry.Contributions[Index].Offset = ContributionOffsets[Index];
ContributionOffsets[Index] +=
(CurEntry.Contributions[Index].Length = Pair.second);
}

uint32_t &InfoSectionOffset =
ContributionOffsets[getContributionIndex(DW_SECT_INFO)];
ContributionOffsets[getContributionIndex(DW_SECT_INFO, IndexVersion)];
if (CurCUIndexSection.empty()) {
bool FoundCUUnit = false;
Out.SwitchSection(InfoSection);
Expand All @@ -737,7 +759,8 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
InfoSectionUnitHeader &Header = *HeaderOrError;

UnitIndexEntry Entry = CurEntry;
auto &C = Entry.Contributions[getContributionIndex(DW_SECT_INFO)];
auto &C = Entry.Contributions[getContributionIndex(DW_SECT_INFO,
IndexVersion)];
C.Offset = InfoSectionOffset;
C.Length = Header.Length + 4;

Expand Down Expand Up @@ -768,11 +791,12 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
if (!FoundCUUnit)
return make_error<DWPError>("no compile unit found in file: " + Input);

// Add types from the .debug_types section from DWARF < 5.
addAllTypes(Out, TypeIndexEntries, TypesSection, CurTypesSection,
CurEntry,
ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES)]);

if (IndexVersion == 2) {
// Add types from the .debug_types section from DWARF < 5.
addAllTypes(
Out, TypeIndexEntries, TypesSection, CurTypesSection, CurEntry,
ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)]);
}
continue;
}

Expand All @@ -785,10 +809,10 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
DataExtractor CUIndexData(CurCUIndexSection, Obj.isLittleEndian(), 0);
if (!CUIndex.parse(CUIndexData))
return make_error<DWPError>("failed to parse cu_index");
if (CUIndex.getVersion() != 2)
return make_error<DWPError>(
"unsupported cu_index version: " + utostr(CUIndex.getVersion()) +
" (only version 2 is supported)");
if (CUIndex.getVersion() != IndexVersion)
return make_error<DWPError>("incompatible cu_index versions, found " +
utostr(CUIndex.getVersion()) +
" and expecting " + utostr(IndexVersion));

Out.SwitchSection(InfoSection);
for (const DWARFUnitIndex::Entry &E : CUIndex.getRows()) {
Expand Down Expand Up @@ -821,12 +845,13 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
for (auto Kind : CUIndex.getColumnKinds()) {
if (!isSupportedSectionKind(Kind))
continue;
auto &C = NewEntry.Contributions[getContributionIndex(Kind)];
auto &C =
NewEntry.Contributions[getContributionIndex(Kind, IndexVersion)];
C.Offset += I->Offset;
C.Length = I->Length;
++I;
}
unsigned Index = getContributionIndex(DW_SECT_INFO);
unsigned Index = getContributionIndex(DW_SECT_INFO, IndexVersion);
auto &C = NewEntry.Contributions[Index];
Out.emitBytes(CUInfoSection);
C.Offset = InfoSectionOffset;
Expand All @@ -841,30 +866,35 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
if (!TUIndex.parse(TUIndexData))
return make_error<DWPError>("failed to parse tu_index");
if (TUIndex.getVersion() != 2)
return make_error<DWPError>(
"unsupported tu_index version: " + utostr(TUIndex.getVersion()) +
" (only version 2 is supported)");
return make_error<DWPError>("expected index version 2, but got: " +
utostr(TUIndex.getVersion()));

addAllTypesFromDWP(
Out, TypeIndexEntries, TUIndex, TypesSection, CurTypesSection.front(),
CurEntry,
ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES)]);
ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)]);
}
}

// Lie about there being no info contributions so the TU index only includes
// the type unit contribution
ContributionOffsets[0] = 0;
if (Version < 5) {
// Lie about there being no info contributions so the TU index only includes
// the type unit contribution for DWARF < 5. In DWARFv5 the TU index has a
// contribution to the info section, so we do not want to lie about it.
ContributionOffsets[0] = 0;
}
writeIndex(Out, MCOFI.getDwarfTUIndexSection(), ContributionOffsets,
TypeIndexEntries);

// Lie about the type contribution
ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES)] = 0;
// Unlie about the info contribution
ContributionOffsets[0] = 1;
TypeIndexEntries, IndexVersion);

if (Version < 5) {
// Lie about the type contribution for DWARF < 5. In DWARFv5 the type
// section does not exist, so no need to do anything about this.
ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)] = 0;
// Unlie about the info contribution
ContributionOffsets[0] = 1;
}

writeIndex(Out, MCOFI.getDwarfCUIndexSection(), ContributionOffsets,
IndexEntries);
IndexEntries, IndexVersion);

return Error::success();
}
Expand Down

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