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[PDB] Simplify symbol handling code, NFC

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- Make mergeSymbolRecords a method of PDBLinker to reduce the number of
parameters it needs.

- Remove a stale FIXME comment about error handling. We already drop
unknown symbol records, log them, and continue.

- Update a comment about why we're copying the symbol record. We do it
to realign the record. We can already mutate the symbol record memory,
it's memory allocated by relocateDebugChunk.

- Avoid the extra `CVSymbol NewSym` variable. We can mutate Sym in
place, which is best, since we're mutating the underlying record anyway.

llvm-svn: 346817
This commit is contained in:
Reid Kleckner 2018-11-13 23:44:39 +00:00
parent 4e97ec94d9
commit 944843c880
1 changed files with 22 additions and 25 deletions
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47
lld/COFF/PDB.cpp
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@ -154,6 +154,10 @@ public:
std::pair<CVIndexMap &, bool /*already there*/>
registerPrecompiledHeaders(uint32_t Signature);
void mergeSymbolRecords(ObjFile *File, const CVIndexMap &IndexMap,
std::vector<ulittle32_t *> &StringTableRefs,
BinaryStreamRef SymData);
/// Add the section map and section contributions to the PDB.
void addSections(ArrayRef<OutputSection *> OutputSections,
ArrayRef<uint8_t> SectionTable);
@ -1028,20 +1032,15 @@ static void addGlobalSymbol(pdb::GSIStreamBuilder &Builder, ObjFile &File,
}
}
static void mergeSymbolRecords(BumpPtrAllocator &Alloc, ObjFile *File,
pdb::GSIStreamBuilder &GsiBuilder,
const CVIndexMap &IndexMap,
TypeCollection &IDTable,
std::vector<ulittle32_t *> &StringTableRefs,
BinaryStreamRef SymData) {
// FIXME: Improve error recovery by warning and skipping records when
// possible.
void PDBLinker::mergeSymbolRecords(ObjFile *File, const CVIndexMap &IndexMap,
std::vector<ulittle32_t *> &StringTableRefs,
BinaryStreamRef SymData) {
ArrayRef<uint8_t> SymsBuffer;
cantFail(SymData.readBytes(0, SymData.getLength(), SymsBuffer));
SmallVector<SymbolScope, 4> Scopes;
auto EC = forEachCodeViewRecord<CVSymbol>(
SymsBuffer, [&](const CVSymbol &Sym) -> llvm::Error {
SymsBuffer, [&](CVSymbol Sym) -> llvm::Error {
// Discover type index references in the record. Skip it if we don't
// know where they are.
SmallVector<TiReference, 32> TypeRefs;
@ -1051,8 +1050,10 @@ static void mergeSymbolRecords(BumpPtrAllocator &Alloc, ObjFile *File,
return Error::success();
}
// Copy the symbol record so we can mutate it.
// Copy the symbol and fix the symbol record alignment. The symbol
// record in the object file may not be aligned.
MutableArrayRef<uint8_t> NewData = copySymbolForPdb(Sym, Alloc);
Sym = CVSymbol(Sym.kind(), NewData);
// Re-map all the type index references.
MutableArrayRef<uint8_t> Contents =
@ -1062,32 +1063,29 @@ static void mergeSymbolRecords(BumpPtrAllocator &Alloc, ObjFile *File,
// An object file may have S_xxx_ID symbols, but these get converted to
// "real" symbols in a PDB.
translateIdSymbols(NewData, IDTable);
translateIdSymbols(NewData, getIDTable());
Sym = CVSymbol(symbolKind(NewData), NewData);
// If this record refers to an offset in the object file's string table,
// add that item to the global PDB string table and re-write the index.
recordStringTableReferences(Sym.kind(), Contents, StringTableRefs);
SymbolKind NewKind = symbolKind(NewData);
// Fill in "Parent" and "End" fields by maintaining a stack of scopes.
CVSymbol NewSym(NewKind, NewData);
if (symbolOpensScope(NewKind))
scopeStackOpen(Scopes, File->ModuleDBI->getNextSymbolOffset(),
NewSym);
else if (symbolEndsScope(NewKind))
if (symbolOpensScope(Sym.kind()))
scopeStackOpen(Scopes, File->ModuleDBI->getNextSymbolOffset(), Sym);
else if (symbolEndsScope(Sym.kind()))
scopeStackClose(Scopes, File->ModuleDBI->getNextSymbolOffset(), File);
// Add the symbol to the globals stream if necessary. Do this before
// adding the symbol to the module since we may need to get the next
// symbol offset, and writing to the module's symbol stream will update
// that offset.
if (symbolGoesInGlobalsStream(NewSym))
addGlobalSymbol(GsiBuilder, *File, NewSym);
if (symbolGoesInGlobalsStream(Sym))
addGlobalSymbol(Builder.getGsiBuilder(), *File, Sym);
// Add the symbol to the module.
if (symbolGoesInModuleStream(NewSym))
File->ModuleDBI->addSymbol(NewSym);
if (symbolGoesInModuleStream(Sym))
File->ModuleDBI->addSymbol(Sym);
return Error::success();
});
cantFail(std::move(EC));
@ -1181,9 +1179,8 @@ void DebugSHandler::handleDebugS(lld::coff::SectionChunk &DebugS) {
break;
}
case DebugSubsectionKind::Symbols: {
mergeSymbolRecords(Linker.Alloc, &File, Linker.Builder.getGsiBuilder(),
IndexMap, Linker.getIDTable(), StringTableReferences,
SS.getRecordData());
Linker.mergeSymbolRecords(&File, IndexMap, StringTableReferences,
SS.getRecordData());
break;
}
default: