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[BOLT][DWARF] Add support for DW_IDX_parent #85285

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Merged
merged 3 commits into from
Mar 15, 2024
Merged

[BOLT][DWARF] Add support for DW_IDX_parent #85285

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c8719cc
[BOLT][DWARF] Add support for DW_IDX_parent
ayermolo Mar 14, 2024
ec7b96a
addressed comments
ayermolo Mar 14, 2024
d3eb837
change to uint32_max
ayermolo Mar 15, 2024
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5 changes: 4 additions & 1 deletion bolt/include/bolt/Core/DIEBuilder.h
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Original file line number Diff line number Diff line change
Expand Up @@ -209,7 +209,10 @@ class DIEBuilder {
void updateReferences();

/// Update the Offset and Size of DIE, populate DebugNames table.
uint32_t finalizeDIEs(DWARFUnit &CU, DIE &Die, uint32_t &CurOffset);
uint32_t
finalizeDIEs(DWARFUnit &CU, DIE &Die,
std::vector<std::optional<BOLTDWARF5AccelTableData *>> &Parents,
uint32_t &CurOffset);

void registerUnit(DWARFUnit &DU, bool NeedSort);

Expand Down
13 changes: 10 additions & 3 deletions bolt/include/bolt/Core/DebugNames.h
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,9 @@ class BOLTDWARF5AccelTableData : public DWARF5AccelTableData {
bool isTU() const { return DWARF5AccelTableData::isTU(); }
std::optional<unsigned> getSecondUnitID() const { return SecondUnitID; }

void setPatchOffset(uint64_t PatchOffset) { OffsetVal = PatchOffset; }
uint64_t getPatchOffset() const { return std::get<uint64_t>(OffsetVal); }

private:
std::optional<unsigned> SecondUnitID;
};
Expand All @@ -51,8 +54,10 @@ class DWARF5AcceleratorTable {
/// Add DWARF5 Accelerator table entry.
/// Input is DWARFUnit being processed, DIE that belongs to it, and potential
/// SkeletonCU if the Unit comes from a DWO section.
void addAccelTableEntry(DWARFUnit &Unit, const DIE &Die,
const std::optional<uint64_t> &DWOID);
std::optional<BOLTDWARF5AccelTableData *>
addAccelTableEntry(DWARFUnit &Unit, const DIE &Die,
const std::optional<uint64_t> &DWOID,
std::optional<BOLTDWARF5AccelTableData *> &Parent);
/// Set current unit being processed.
void setCurrentUnit(DWARFUnit &Unit, const uint64_t UnitStartOffset);
/// Emit Accelerator table.
Expand Down Expand Up @@ -121,6 +126,8 @@ class DWARF5AcceleratorTable {
llvm::DenseMap<llvm::hash_code, uint64_t> StrCacheToOffsetMap;
// Contains DWO ID to CUList Index.
llvm::DenseMap<uint64_t, uint32_t> CUOffsetsToPatch;
// Contains a map of Entry ID to Entry relative offset.
llvm::DenseMap<uint64_t, uint32_t> EntryRelativeOffsets;
/// Adds Unit to either CUList, LocalTUList or ForeignTUList.
/// Input Unit being processed, and DWO ID if Unit is being processed comes
/// from a DWO section.
Expand All @@ -143,7 +150,7 @@ class DWARF5AcceleratorTable {
/// Write Entries.
void writeEntries();
/// Write an Entry.
void writeEntry(const BOLTDWARF5AccelTableData &Entry);
void writeEntry(BOLTDWARF5AccelTableData &Entry);
/// Write augmentation_string for BOLT.
void writeAugmentationString();
/// Emit out Header for DWARF5 Accelerator table.
Expand Down
28 changes: 22 additions & 6 deletions bolt/lib/Core/DIEBuilder.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -377,20 +377,32 @@ getUnitForOffset(DIEBuilder &Builder, DWARFContext &DWCtx,
return nullptr;
}

uint32_t DIEBuilder::finalizeDIEs(DWARFUnit &CU, DIE &Die,
uint32_t &CurOffset) {
uint32_t DIEBuilder::finalizeDIEs(
DWARFUnit &CU, DIE &Die,
std::vector<std::optional<BOLTDWARF5AccelTableData *>> &Parents,
uint32_t &CurOffset) {
getState().DWARFDieAddressesParsed.erase(Die.getOffset());
uint32_t CurSize = 0;
Die.setOffset(CurOffset);
DebugNamesTable.addAccelTableEntry(
CU, Die, SkeletonCU ? SkeletonCU->getDWOId() : std::nullopt);
std::optional<BOLTDWARF5AccelTableData *> NameEntry =
DebugNamesTable.addAccelTableEntry(
CU, Die, SkeletonCU ? SkeletonCU->getDWOId() : std::nullopt,
Parents.back());
// It is possible that an indexed debugging information entry has a parent
// that is not indexed (for example, if its parent does not have a name
// attribute). In such a case, a parent attribute may point to a nameless
// index entry (that is, one that cannot be reached from any entry in the name
// table), or it may point to the nearest ancestor that does have an index
// entry.
if (NameEntry)
Parents.push_back(std::move(NameEntry));
for (DIEValue &Val : Die.values())
CurSize += Val.sizeOf(CU.getFormParams());
CurSize += getULEB128Size(Die.getAbbrevNumber());
CurOffset += CurSize;

for (DIE &Child : Die.children()) {
uint32_t ChildSize = finalizeDIEs(CU, Child, CurOffset);
uint32_t ChildSize = finalizeDIEs(CU, Child, Parents, CurOffset);
CurSize += ChildSize;
}
// for children end mark.
Expand All @@ -400,6 +412,8 @@ uint32_t DIEBuilder::finalizeDIEs(DWARFUnit &CU, DIE &Die,
}

Die.setSize(CurSize);
if (NameEntry)
Parents.pop_back();

return CurSize;
}
Expand All @@ -410,7 +424,9 @@ void DIEBuilder::finish() {
uint32_t HeaderSize = CU.getHeaderSize();
uint32_t CurOffset = HeaderSize;
DebugNamesTable.setCurrentUnit(CU, UnitStartOffset);
finalizeDIEs(CU, *UnitDIE, CurOffset);
std::vector<std::optional<BOLTDWARF5AccelTableData *>> Parents;
Parents.push_back(std::nullopt);
finalizeDIEs(CU, *UnitDIE, Parents, CurOffset);

DWARFUnitInfo &CurUnitInfo = getUnitInfoByDwarfUnit(CU);
CurUnitInfo.UnitOffset = UnitStartOffset;
Expand Down
82 changes: 70 additions & 12 deletions bolt/lib/Core/DebugNames.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/LEB128.h"
#include <cstdint>
#include <optional>

namespace llvm {
namespace bolt {
Expand Down Expand Up @@ -163,10 +164,16 @@ static uint64_t getNameOffset(BinaryContext &BC, DWARFUnit &Unit,
Index * DwarfOffsetByteSize);
}

void DWARF5AcceleratorTable::addAccelTableEntry(
DWARFUnit &Unit, const DIE &Die, const std::optional<uint64_t> &DWOID) {
static uint64_t getEntryID(const BOLTDWARF5AccelTableData &Entry) {
return reinterpret_cast<uint64_t>(&Entry);
}

std::optional<BOLTDWARF5AccelTableData *>
DWARF5AcceleratorTable::addAccelTableEntry(
DWARFUnit &Unit, const DIE &Die, const std::optional<uint64_t> &DWOID,
std::optional<BOLTDWARF5AccelTableData *> &Parent) {
if (Unit.getVersion() < 5 || !NeedToCreate)
return;
return std::nullopt;
std::string NameToUse = "";
auto canProcess = [&](const DIE &Die) -> bool {
switch (Die.getTag()) {
Expand Down Expand Up @@ -217,7 +224,7 @@ void DWARF5AcceleratorTable::addAccelTableEntry(
};

if (!canProcess(Die))
return;
return std::nullopt;

// Addes a Unit to either CU, LocalTU or ForeignTU list the first time we
// encounter it.
Expand All @@ -227,10 +234,11 @@ void DWARF5AcceleratorTable::addAccelTableEntry(
addUnit(Unit, DWOID);
}

auto addEntry = [&](DIEValue ValName) -> void {
auto addEntry =
[&](DIEValue ValName) -> std::optional<BOLTDWARF5AccelTableData *> {
if ((!ValName || ValName.getForm() == dwarf::DW_FORM_string) &&
NameToUse.empty())
return;
return std::nullopt;
std::string Name = "";
uint64_t NameIndexOffset = 0;
if (NameToUse.empty()) {
Expand Down Expand Up @@ -275,13 +283,23 @@ void DWARF5AcceleratorTable::addAccelTableEntry(
<< ".\n";
SecondIndex = Iter->second;
}
std::optional<uint64_t> ParentOffset =
(Parent ? std::optional<uint64_t>(getEntryID(**Parent)) : std::nullopt);
// This will be populated later in writeEntry.
// This way only parent entries get tracked.
// Keeping memory footprint down.
if (ParentOffset)
EntryRelativeOffsets.insert({*ParentOffset, 0});
It.Values.push_back(new (Allocator) BOLTDWARF5AccelTableData(
Die.getOffset(), std::nullopt, DieTag, UnitID, IsTU, SecondIndex));
Die.getOffset(), ParentOffset, DieTag, UnitID, IsTU, SecondIndex));
return It.Values.back();
};

addEntry(Die.findAttribute(dwarf::Attribute::DW_AT_name));
addEntry(Die.findAttribute(dwarf::Attribute::DW_AT_linkage_name));
return;
std::optional<BOLTDWARF5AccelTableData *> NameEntry =
addEntry(Die.findAttribute(dwarf::Attribute::DW_AT_name));
std::optional<BOLTDWARF5AccelTableData *> LinkageNameEntry =
addEntry(Die.findAttribute(dwarf::Attribute::DW_AT_linkage_name));
return NameEntry ? NameEntry : LinkageNameEntry;
}

/// Algorithm from llvm implementation.
Expand Down Expand Up @@ -382,6 +400,11 @@ void DWARF5AcceleratorTable::populateAbbrevsMap() {
if (SecondEntryRet)
Abbrev.addAttribute(SecondEntryRet->Encoding);
Abbrev.addAttribute({dwarf::DW_IDX_die_offset, dwarf::DW_FORM_ref4});
if (std::optional<uint64_t> Offset = Value->getParentDieOffset())
Abbrev.addAttribute({dwarf::DW_IDX_parent, dwarf::DW_FORM_ref4});
else
Abbrev.addAttribute(
{dwarf::DW_IDX_parent, dwarf::DW_FORM_flag_present});
FoldingSetNodeID ID;
Abbrev.Profile(ID);
void *InsertPos;
Expand All @@ -401,7 +424,11 @@ void DWARF5AcceleratorTable::populateAbbrevsMap() {
}
}

void DWARF5AcceleratorTable::writeEntry(const BOLTDWARF5AccelTableData &Entry) {
void DWARF5AcceleratorTable::writeEntry(BOLTDWARF5AccelTableData &Entry) {
const uint64_t EntryID = getEntryID(Entry);
if (EntryRelativeOffsets.find(EntryID) != EntryRelativeOffsets.end())
EntryRelativeOffsets[EntryID] = EntriesBuffer->size();

const std::optional<DWARF5AccelTable::UnitIndexAndEncoding> EntryRet =
getIndexForEntry(Entry);
// For forgeign type (FTU) units that need to refer to the FTU and to the CU.
Expand Down Expand Up @@ -456,6 +483,17 @@ void DWARF5AcceleratorTable::writeEntry(const BOLTDWARF5AccelTableData &Entry) {
llvm::endianness::little);
break;
}
case dwarf::DW_IDX_parent: {
assert(
(AttrEnc.Form == dwarf::DW_FORM_ref4 && Entry.getParentDieOffset()) ||
AttrEnc.Form == dwarf::DW_FORM_flag_present);
if (std::optional<uint64_t> ParentOffset = Entry.getParentDieOffset()) {
Entry.setPatchOffset(EntriesBuffer->size());
support::endian::write(*Entriestream, static_cast<uint32_t>(0xBADF00D),
llvm::endianness::little);
}
break;
}
}
}
}
Expand All @@ -464,13 +502,33 @@ void DWARF5AcceleratorTable::writeEntries() {
for (auto &Bucket : getBuckets()) {
for (DWARF5AcceleratorTable::HashData *Hash : Bucket) {
Hash->EntryOffset = EntriesBuffer->size();
for (const BOLTDWARF5AccelTableData *Value : Hash->Values) {
for (BOLTDWARF5AccelTableData *Value : Hash->Values) {
writeEntry(*Value);
}
support::endian::write(*Entriestream, static_cast<uint8_t>(0),
llvm::endianness::little);
}
}
// Patching parent offsets.
for (auto &Bucket : getBuckets()) {
for (DWARF5AcceleratorTable::HashData *Hash : Bucket) {
for (BOLTDWARF5AccelTableData *Entry : Hash->Values) {
std::optional<uint64_t> ParentOffset = Entry->getParentDieOffset();
if (!ParentOffset)
continue;
if (const auto Iter = EntryRelativeOffsets.find(*ParentOffset);
Iter != EntryRelativeOffsets.end()) {
const uint64_t PatchOffset = Entry->getPatchOffset();
uint32_t *Ptr = reinterpret_cast<uint32_t *>(
&EntriesBuffer.get()->data()[PatchOffset]);
*Ptr = Iter->second;
} else {
BC.errs() << "Could not find entry with offset " << *ParentOffset
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Is it a warning or an error and when can it get triggered? If the former, change the message to: "BOLT-WARNING: could not find...".

<< "\n";
}
}
}
}
}

void DWARF5AcceleratorTable::writeAugmentationString() {
Expand Down
16 changes: 14 additions & 2 deletions bolt/test/X86/dwarf5-debug-names-generate-debug-names.test
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Original file line number Diff line number Diff line change
Expand Up @@ -14,15 +14,15 @@
; BOLT: [[OFFSET2:0x[0-9a-f]*]]: Compile Unit
; BOLT: Name Index @ 0x0 {
; BOLT-NEXT: Header {
; BOLT-NEXT: Length: 0x103
; BOLT-NEXT: Length: 0x109
; BOLT-NEXT: Format: DWARF32
; BOLT-NEXT: Version: 5
; BOLT-NEXT: CU count: 2
; BOLT-NEXT: Local TU count: 0
; BOLT-NEXT: Foreign TU count: 0
; BOLT-NEXT: Bucket count: 8
; BOLT-NEXT: Name count: 8
; BOLT-NEXT: Abbreviations table size: 0x19
; BOLT-NEXT: Abbreviations table size: 0x1F
; BOLT-NEXT: Augmentation: 'BOLT'
; BOLT-NEXT: }
; BOLT-NEXT: Compilation Unit offsets [
Expand All @@ -34,16 +34,19 @@
; BOLT-NEXT: Tag: DW_TAG_base_type
; BOLT-NEXT: DW_IDX_compile_unit: DW_FORM_data1
; BOLT-NEXT: DW_IDX_die_offset: DW_FORM_ref4
; BOLT-NEXT: DW_IDX_parent: DW_FORM_flag_present
; BOLT-NEXT: }
; BOLT-NEXT: Abbreviation [[ABBREV2:0x[0-9a-f]*]] {
; BOLT-NEXT: Tag: DW_TAG_subprogram
; BOLT-NEXT: DW_IDX_compile_unit: DW_FORM_data1
; BOLT-NEXT: DW_IDX_die_offset: DW_FORM_ref4
; BOLT-NEXT: DW_IDX_parent: DW_FORM_flag_present
; BOLT-NEXT: }
; BOLT-NEXT: Abbreviation [[ABBREV3:0x[0-9a-f]*]] {
; BOLT-NEXT: Tag: DW_TAG_variable
; BOLT-NEXT: DW_IDX_compile_unit: DW_FORM_data1
; BOLT-NEXT: DW_IDX_die_offset: DW_FORM_ref4
; BOLT-NEXT: DW_IDX_parent: DW_FORM_flag_present
; BOLT-NEXT: }
; BOLT-NEXT: ]
; BOLT-NEXT: Bucket 0 [
Expand All @@ -55,12 +58,14 @@
; BOLT-NEXT: Tag: DW_TAG_base_type
; BOLT-NEXT: DW_IDX_compile_unit: 0x01
; BOLT-NEXT: DW_IDX_die_offset: 0x00000033
; BOLT-NEXT: DW_IDX_parent: <parent not indexed>
; BOLT-NEXT: }
; BOLT-NEXT: Entry @ {{.+}} {
; BOLT-NEXT: Abbrev: [[ABBREV1]]
; BOLT-NEXT: Tag: DW_TAG_base_type
; BOLT-NEXT: DW_IDX_compile_unit: 0x00
; BOLT-NEXT: DW_IDX_die_offset: 0x0000007f
; BOLT-NEXT: DW_IDX_parent: <parent not indexed>
; BOLT-NEXT: }
; BOLT-NEXT: }
; BOLT-NEXT: ]
Expand All @@ -73,6 +78,7 @@
; BOLT-NEXT: Tag: DW_TAG_subprogram
; BOLT-NEXT: DW_IDX_compile_unit: 0x01
; BOLT-NEXT: DW_IDX_die_offset: 0x0000005e
; BOLT-NEXT: DW_IDX_parent: <parent not indexed>
; BOLT-NEXT: }
; BOLT-NEXT: }
; BOLT-NEXT: Name 3 {
Expand All @@ -83,6 +89,7 @@
; BOLT-NEXT: Tag: DW_TAG_subprogram
; BOLT-NEXT: DW_IDX_compile_unit: 0x00
; BOLT-NEXT: DW_IDX_die_offset: 0x00000028
; BOLT-NEXT: DW_IDX_parent: <parent not indexed>
; BOLT-NEXT: }
; BOLT-NEXT: }
; BOLT-NEXT: ]
Expand All @@ -95,6 +102,7 @@
; BOLT-NEXT: Tag: DW_TAG_subprogram
; BOLT-NEXT: DW_IDX_compile_unit: 0x00
; BOLT-NEXT: DW_IDX_die_offset: 0x00000028
; BOLT-NEXT: DW_IDX_parent: <parent not indexed>
; BOLT-NEXT: }
; BOLT-NEXT: }
; BOLT-NEXT: Name 5 {
Expand All @@ -105,6 +113,7 @@
; BOLT-NEXT: Tag: DW_TAG_subprogram
; BOLT-NEXT: DW_IDX_compile_unit: 0x00
; BOLT-NEXT: DW_IDX_die_offset: 0x00000049
; BOLT-NEXT: DW_IDX_parent: <parent not indexed>
; BOLT-NEXT: }
; BOLT-NEXT: }
; BOLT-NEXT: Name 6 {
Expand All @@ -115,6 +124,7 @@
; BOLT-NEXT: Tag: DW_TAG_variable
; BOLT-NEXT: DW_IDX_compile_unit: 0x01
; BOLT-NEXT: DW_IDX_die_offset: 0x00000028
; BOLT-NEXT: DW_IDX_parent: <parent not indexed>
; BOLT-NEXT: }
; BOLT-NEXT: }
; BOLT-NEXT: ]
Expand All @@ -127,6 +137,7 @@
; BOLT-NEXT: Tag: DW_TAG_base_type
; BOLT-NEXT: DW_IDX_compile_unit: 0x00
; BOLT-NEXT: DW_IDX_die_offset: 0x00000092
; BOLT-NEXT: DW_IDX_parent: <parent not indexed>
; BOLT-NEXT: }
; BOLT-NEXT: }
; BOLT-NEXT: ]
Expand All @@ -145,6 +156,7 @@
; BOLT-NEXT: Tag: DW_TAG_subprogram
; BOLT-NEXT: DW_IDX_compile_unit: 0x01
; BOLT-NEXT: DW_IDX_die_offset: 0x0000005e
; BOLT-NEXT: DW_IDX_parent: <parent not indexed>
; BOLT-NEXT: }
; BOLT-NEXT: }
; BOLT-NEXT: ]
Expand Down
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