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Add support to properly reference private symbols on relocation entries.

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Use proper relocation type to build relocations for JumpTables (rodata
sections).

llvm-svn: 76326
This commit is contained in:
Bruno Cardoso Lopes
2009-07-18 19:30:09 +00:00
parent eb6bcf3462
commit 484e90b45e
7 changed files with 103 additions and 18 deletions
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40
llvm/lib/CodeGen/ELFWriter.cpp
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@@ -296,8 +296,16 @@ void ELFWriter::EmitGlobal(const GlobalValue *GV) {
}
}
if (!GV->hasPrivateLinkage())
// Private symbols must never go to the symbol table.
unsigned SymIdx = 0;
if (GV->hasPrivateLinkage()) {
PrivateSyms.push_back(GblSym);
SymIdx = PrivateSyms.size()-1;
} else {
SymbolList.push_back(GblSym);
}
GblSymLookup[GV] = SymIdx;
}
void ELFWriter::EmitGlobalConstantStruct(const ConstantStruct *CVS,
@@ -394,20 +402,16 @@ bool ELFWriter::doFinalization(Module &M) {
for (Module::global_iterator I = M.global_begin(), E = M.global_end();
I != E; ++I) {
EmitGlobal(I);
GblSymLookup[I] = 0;
}
// Emit all pending globals
// TODO: this should be done only for referenced symbols
for (SetVector<GlobalValue*>::const_iterator I = PendingGlobals.begin(),
E = PendingGlobals.end(); I != E; ++I) {
// No need to emit the symbol again
if (GblSymLookup.find(*I) != GblSymLookup.end())
continue;
EmitGlobal(*I);
GblSymLookup[*I] = 0;
}
// Emit non-executable stack note
@@ -480,7 +484,8 @@ void ELFWriter::EmitRelocations() {
MRE = Relos.end(); MRI != MRE; ++MRI) {
MachineRelocation &MR = *MRI;
// Offset from the start of the section containing the symbol
// Holds the relocatable field address as an offset from the
// beginning of the section where it lives
unsigned Offset = MR.getMachineCodeOffset();
// Symbol index in the symbol table
@@ -498,15 +503,34 @@ void ELFWriter::EmitRelocations() {
if (MR.isGlobalValue()) {
const GlobalValue *G = MR.getGlobalValue();
SymIdx = GblSymLookup[G];
Addend = TEW->getAddendForRelTy(RelType);
if (G->hasPrivateLinkage()) {
// If the target uses a section offset in the relocation:
// SymIdx + Addend = section sym for global + section offset
unsigned SectionIdx = PrivateSyms[SymIdx]->SectionIdx;
Addend = PrivateSyms[SymIdx]->Value;
SymIdx = SectionList[SectionIdx]->getSymbolTableIndex();
} else {
Addend = TEW->getDefaultAddendForRelTy(RelType);
}
} else {
// Get the symbol index for the section symbol referenced
// by the relocation
unsigned SectionIdx = MR.getConstantVal();
SymIdx = SectionList[SectionIdx]->Sym->SymTabIdx;
SymIdx = SectionList[SectionIdx]->getSymbolTableIndex();
Addend = (uint64_t)MR.getResultPointer();
}
// The target without addend on the relocation symbol must be
// patched in the relocation place itself to contain the addend
if (!HasRelA) {
if (TEW->getRelocationTySize(RelType) == 32)
S.fixWord32(Addend, Offset);
else if (TEW->getRelocationTySize(RelType) == 64)
S.fixWord64(Addend, Offset);
else
llvm_unreachable("don't know howto patch relocatable field");
}
// Get the relocation entry and emit to the relocation section
ELFRelocation Rel(Offset, SymIdx, RelType, HasRelA, Addend);
EmitRelocation(RelSec, Rel, HasRelA);