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Implement relocation-overflow behavior for PE/COFF. 

This needs a test, but it will take some time to figure
out the best way to get an input that will produce > 2^16 relocs.

Patch by Graydon Hoare!

llvm-svn: 152787
This commit is contained in:
Michael J. Spencer 2012-03-15 09:03:03 +00:00
parent d6533ccd48
commit fa39bd2d42
1 changed files with 29 additions and 2 deletions
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31
llvm/lib/MC/WinCOFFObjectWriter.cpp
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@ -783,9 +783,22 @@ void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
}
if (Sec->Relocations.size() > 0) {
Sec->Header.NumberOfRelocations = Sec->Relocations.size();
bool RelocationsOverflow = Sec->Relocations.size() >= 0xffff;
if (RelocationsOverflow) {
// Signal overflow by setting NumberOfSections to max value. Actual
// size is found in reloc #0. Microsoft tools understand this.
Sec->Header.NumberOfRelocations = 0xffff;
} else {
Sec->Header.NumberOfRelocations = Sec->Relocations.size();
}
Sec->Header.PointerToRelocations = offset;
if (RelocationsOverflow) {
// Reloc #0 will contain actual count, so make room for it.
offset += COFF::RelocationSize;
}
offset += COFF::RelocationSize * Sec->Relocations.size();
for (relocations::iterator cr = Sec->Relocations.begin(),
@ -820,8 +833,12 @@ void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
MCAssembler::const_iterator j, je;
for (i = Sections.begin(), ie = Sections.end(); i != ie; i++)
if ((*i)->Number != -1)
if ((*i)->Number != -1) {
if ((*i)->Relocations.size() >= 0xffff) {
(*i)->Header.Characteristics |= COFF::IMAGE_SCN_LNK_NRELOC_OVFL;
}
WriteSectionHeader((*i)->Header);
}
for (i = Sections.begin(), ie = Sections.end(),
j = Asm.begin(), je = Asm.end();
@ -841,6 +858,16 @@ void WinCOFFObjectWriter::WriteObject(MCAssembler &Asm,
assert(OS.tell() == (*i)->Header.PointerToRelocations &&
"Section::PointerToRelocations is insane!");
if ((*i)->Relocations.size() >= 0xffff) {
// In case of overflow, write actual relocation count as first
// relocation. Including the synthetic reloc itself (+ 1).
COFF::relocation r;
r.VirtualAddress = (*i)->Relocations.size() + 1;
r.SymbolTableIndex = 0;
r.Type = 0;
WriteRelocation(r);
}
for (relocations::const_iterator k = (*i)->Relocations.begin(),
ke = (*i)->Relocations.end();
k != ke; k++) {