[llvm] [LLVM][DebugInfo] Refactor some code for easier sharing. (PR #82153)
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Sat Feb 17 22:35:06 PST 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-debuginfo
Author: None (cmtice)
<details>
<summary>Changes</summary>
Refactor the code that calculates the offsets for the various pieces of the DWARF .debug_names index section, to make it easier to share the code with other tools, such as LLD.
---
Full diff: https://github.com/llvm/llvm-project/pull/82153.diff
2 Files Affected:
- (modified) llvm/include/llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h (+21-7)
- (modified) llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp (+46-25)
``````````diff
diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h
index a26c44bf7e9c29..0dd5ed55efe702 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h
@@ -562,6 +562,17 @@ class DWARFDebugNames : public DWARFAcceleratorTable {
uint64_t getEntryOffset() const { return EntryOffset; }
};
+ // Offsets for the start of various important tables from the start of the
+ // section.
+ struct DWARFDebugNamesOffsets {
+ uint64_t CUsBase;
+ uint64_t BucketsBase;
+ uint64_t HashesBase;
+ uint64_t StringOffsetsBase;
+ uint64_t EntryOffsetsBase;
+ uint64_t EntriesBase;
+ };
+
/// Represents a single accelerator table within the DWARF v5 .debug_names
/// section.
class NameIndex {
@@ -572,12 +583,7 @@ class DWARFDebugNames : public DWARFAcceleratorTable {
// Base of the whole unit and of various important tables, as offsets from
// the start of the section.
uint64_t Base;
- uint64_t CUsBase;
- uint64_t BucketsBase;
- uint64_t HashesBase;
- uint64_t StringOffsetsBase;
- uint64_t EntryOffsetsBase;
- uint64_t EntriesBase;
+ DWARFDebugNamesOffsets Offsets;
void dumpCUs(ScopedPrinter &W) const;
void dumpLocalTUs(ScopedPrinter &W) const;
@@ -638,7 +644,7 @@ class DWARFDebugNames : public DWARFAcceleratorTable {
/// Returns the Entry at the relative `Offset` from the start of the Entry
/// pool.
Expected<Entry> getEntryAtRelativeOffset(uint64_t Offset) const {
- auto OffsetFromSection = Offset + this->EntriesBase;
+ auto OffsetFromSection = Offset + this->Offsets.EntriesBase;
return getEntry(&OffsetFromSection);
}
@@ -793,6 +799,14 @@ class DWARFDebugNames : public DWARFAcceleratorTable {
const NameIndex *getCUNameIndex(uint64_t CUOffset);
};
+// Calculates the starting offsets for various sections within the
+// debug_names section. This has been pulled out of DWARFDebugNames, to
+// allow easier sharing of the code with other tools, such as LLD.
+uint64_t FindDebugNamesOffsets(DWARFDebugNames::DWARFDebugNamesOffsets &Offsets,
+ uint64_t HdrSize,
+ const dwarf::DwarfFormat Format,
+ const DWARFDebugNames::Header &Hdr);
+
/// If `Name` is the name of a templated function that includes template
/// parameters, returns a substring of `Name` containing no template
/// parameters.
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp b/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp
index 78f819dd052aac..68adad517f9364 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFAcceleratorTable.cpp
@@ -510,7 +510,7 @@ DWARFDebugNames::Abbrev DWARFDebugNames::AbbrevMapInfo::getTombstoneKey() {
Expected<DWARFDebugNames::AttributeEncoding>
DWARFDebugNames::NameIndex::extractAttributeEncoding(uint64_t *Offset) {
- if (*Offset >= EntriesBase) {
+ if (*Offset >= Offsets.EntriesBase) {
return createStringError(errc::illegal_byte_sequence,
"Incorrectly terminated abbreviation table.");
}
@@ -536,7 +536,7 @@ DWARFDebugNames::NameIndex::extractAttributeEncodings(uint64_t *Offset) {
Expected<DWARFDebugNames::Abbrev>
DWARFDebugNames::NameIndex::extractAbbrev(uint64_t *Offset) {
- if (*Offset >= EntriesBase) {
+ if (*Offset >= Offsets.EntriesBase) {
return createStringError(errc::illegal_byte_sequence,
"Incorrectly terminated abbreviation table.");
}
@@ -552,6 +552,37 @@ DWARFDebugNames::NameIndex::extractAbbrev(uint64_t *Offset) {
return Abbrev(Code, dwarf::Tag(Tag), AbbrevOffset, std::move(*AttrEncOr));
}
+uint64_t llvm::FindDebugNamesOffsets(
+ DWARFDebugNames::DWARFDebugNamesOffsets &Offsets,
+ uint64_t HdrSize,
+ dwarf::DwarfFormat Format,
+ const DWARFDebugNames::Header &Hdr) {
+ uint32_t DwarfSize = (Format == llvm::dwarf::DwarfFormat::DWARF32) ? 4 : 8;
+ uint64_t Offset = HdrSize;
+ Offsets.CUsBase = Offset;
+ Offset += Hdr.CompUnitCount * DwarfSize;
+ Offset += Hdr.LocalTypeUnitCount * DwarfSize;
+ Offset += Hdr.ForeignTypeUnitCount * 8;
+
+ Offsets.BucketsBase = Offset;
+ Offset += Hdr.BucketCount * 4;
+
+ Offsets.HashesBase = Offset;
+ if (Hdr.BucketCount > 0)
+ Offset += Hdr.NameCount * 4;
+
+ Offsets.StringOffsetsBase = Offset;
+ Offset += Hdr.NameCount * DwarfSize;
+
+ Offsets.EntryOffsetsBase = Offset;
+ Offset += Hdr.NameCount * DwarfSize;
+
+ Offset += Hdr.AbbrevTableSize;
+ Offsets.EntriesBase = Offset;
+
+ return Offset;
+}
+
Error DWARFDebugNames::NameIndex::extract() {
const DWARFDataExtractor &AS = Section.AccelSection;
uint64_t Offset = Base;
@@ -559,25 +590,15 @@ Error DWARFDebugNames::NameIndex::extract() {
return E;
const unsigned SectionOffsetSize = dwarf::getDwarfOffsetByteSize(Hdr.Format);
- CUsBase = Offset;
- Offset += Hdr.CompUnitCount * SectionOffsetSize;
- Offset += Hdr.LocalTypeUnitCount * SectionOffsetSize;
- Offset += Hdr.ForeignTypeUnitCount * 8;
- BucketsBase = Offset;
- Offset += Hdr.BucketCount * 4;
- HashesBase = Offset;
- if (Hdr.BucketCount > 0)
- Offset += Hdr.NameCount * 4;
- StringOffsetsBase = Offset;
- Offset += Hdr.NameCount * SectionOffsetSize;
- EntryOffsetsBase = Offset;
- Offset += Hdr.NameCount * SectionOffsetSize;
+ Offset = FindDebugNamesOffsets(Offsets, Offset, Hdr.Format, Hdr);
+
+ Offset = Offsets.EntryOffsetsBase + (Hdr.NameCount * SectionOffsetSize);
if (!AS.isValidOffsetForDataOfSize(Offset, Hdr.AbbrevTableSize))
return createStringError(errc::illegal_byte_sequence,
"Section too small: cannot read abbreviations.");
- EntriesBase = Offset + Hdr.AbbrevTableSize;
+ Offsets.EntriesBase = Offset + Hdr.AbbrevTableSize;
for (;;) {
auto AbbrevOr = extractAbbrev(&Offset);
@@ -679,7 +700,7 @@ void DWARFDebugNames::Entry::dumpParentIdx(
return;
}
- auto AbsoluteOffset = NameIdx->EntriesBase + FormValue.getRawUValue();
+ auto AbsoluteOffset = NameIdx->Offsets.EntriesBase + FormValue.getRawUValue();
W.getOStream() << "Entry @ 0x" + Twine::utohexstr(AbsoluteOffset);
}
@@ -708,14 +729,14 @@ std::error_code DWARFDebugNames::SentinelError::convertToErrorCode() const {
uint64_t DWARFDebugNames::NameIndex::getCUOffset(uint32_t CU) const {
assert(CU < Hdr.CompUnitCount);
const unsigned SectionOffsetSize = dwarf::getDwarfOffsetByteSize(Hdr.Format);
- uint64_t Offset = CUsBase + SectionOffsetSize * CU;
+ uint64_t Offset = Offsets.CUsBase + SectionOffsetSize * CU;
return Section.AccelSection.getRelocatedValue(SectionOffsetSize, &Offset);
}
uint64_t DWARFDebugNames::NameIndex::getLocalTUOffset(uint32_t TU) const {
assert(TU < Hdr.LocalTypeUnitCount);
const unsigned SectionOffsetSize = dwarf::getDwarfOffsetByteSize(Hdr.Format);
- uint64_t Offset = CUsBase + SectionOffsetSize * (Hdr.CompUnitCount + TU);
+ uint64_t Offset = Offsets.CUsBase + SectionOffsetSize * (Hdr.CompUnitCount + TU);
return Section.AccelSection.getRelocatedValue(SectionOffsetSize, &Offset);
}
@@ -723,7 +744,7 @@ uint64_t DWARFDebugNames::NameIndex::getForeignTUSignature(uint32_t TU) const {
assert(TU < Hdr.ForeignTypeUnitCount);
const unsigned SectionOffsetSize = dwarf::getDwarfOffsetByteSize(Hdr.Format);
uint64_t Offset =
- CUsBase +
+ Offsets.CUsBase +
SectionOffsetSize * (Hdr.CompUnitCount + Hdr.LocalTypeUnitCount) + 8 * TU;
return Section.AccelSection.getU64(&Offset);
}
@@ -759,28 +780,28 @@ DWARFDebugNames::NameIndex::getNameTableEntry(uint32_t Index) const {
assert(0 < Index && Index <= Hdr.NameCount);
const unsigned SectionOffsetSize = dwarf::getDwarfOffsetByteSize(Hdr.Format);
uint64_t StringOffsetOffset =
- StringOffsetsBase + SectionOffsetSize * (Index - 1);
+ Offsets.StringOffsetsBase + SectionOffsetSize * (Index - 1);
uint64_t EntryOffsetOffset =
- EntryOffsetsBase + SectionOffsetSize * (Index - 1);
+ Offsets.EntryOffsetsBase + SectionOffsetSize * (Index - 1);
const DWARFDataExtractor &AS = Section.AccelSection;
uint64_t StringOffset =
AS.getRelocatedValue(SectionOffsetSize, &StringOffsetOffset);
uint64_t EntryOffset = AS.getUnsigned(&EntryOffsetOffset, SectionOffsetSize);
- EntryOffset += EntriesBase;
+ EntryOffset += Offsets.EntriesBase;
return {Section.StringSection, Index, StringOffset, EntryOffset};
}
uint32_t
DWARFDebugNames::NameIndex::getBucketArrayEntry(uint32_t Bucket) const {
assert(Bucket < Hdr.BucketCount);
- uint64_t BucketOffset = BucketsBase + 4 * Bucket;
+ uint64_t BucketOffset = Offsets.BucketsBase + 4 * Bucket;
return Section.AccelSection.getU32(&BucketOffset);
}
uint32_t DWARFDebugNames::NameIndex::getHashArrayEntry(uint32_t Index) const {
assert(0 < Index && Index <= Hdr.NameCount);
- uint64_t HashOffset = HashesBase + 4 * (Index - 1);
+ uint64_t HashOffset = Offsets.HashesBase + 4 * (Index - 1);
return Section.AccelSection.getU32(&HashOffset);
}
``````````
</details>
https://github.com/llvm/llvm-project/pull/82153
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