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[ELF] .ARM.exidx sentinel section should use InputSectionDescriptions. 

This change converts the writing of the .ARM.exidx sentinel section to use
the InputSectionDescriptions instead of OutputSection::Sections this is in
preparation for the retirement of OutputSection::Sections.
    
Differential Revision: https://reviews.llvm.org/D33500

llvm-svn: 304289
This commit is contained in:
Peter Smith 2017-05-31 09:02:21 +00:00
parent 5ecc5166d9
commit ea79b215d6
1 changed files with 16 additions and 6 deletions
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22
lld/ELF/SyntheticSections.cpp
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@ -2186,13 +2186,23 @@ ARMExidxSentinelSection::ARMExidxSentinelSection()
// This section will have been sorted last in the .ARM.exidx table.
// This table entry will have the form:
// | PREL31 upper bound of code that has exception tables | EXIDX_CANTUNWIND |
// The sentinel must have the PREL31 value of an address higher than any
// address described by any other table entry.
void ARMExidxSentinelSection::writeTo(uint8_t *Buf) {
// Get the InputSection before us, we are by definition last
auto RI = this->OutSec->Sections.rbegin();
InputSection *LE = *(++RI);
InputSection *LC = cast<InputSection>(LE->getLinkOrderDep());
uint64_t S = LC->OutSec->Addr + LC->getOffset(LC->getSize());
uint64_t P = this->getVA();
// The Sections are sorted in order of ascending PREL31 address with the
// sentinel last. We need to find the InputSection that precedes the
// sentinel. By construction the Sentinel is in the last
// InputSectionDescription as the InputSection that precedes it.
OutputSectionCommand *C = Script->getCmd(OutSec);
auto ISD = std::find_if(C->Commands.rbegin(), C->Commands.rend(),
[](const BaseCommand *Base) {
return isa<InputSectionDescription>(Base);
});
auto L = cast<InputSectionDescription>(*ISD);
InputSection *Highest = L->Sections[L->Sections.size() - 2];
InputSection *LS = cast<InputSection>(Highest->getLinkOrderDep());
uint64_t S = LS->OutSec->Addr + LS->getOffset(LS->getSize());
uint64_t P = getVA();
Target->relocateOne(Buf, R_ARM_PREL31, S - P);
write32le(Buf + 4, 0x1);
}