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Support for 64-bit PC-relative relocations for X86_64

ELF files generated for X86_64 targets may contain 64-bit PC-relative 
relocations. For instance, an exception handler table entry contains the start 
of exception-throwing frame relative to the start of exception handler. As these 
two labels belong to different sections, their difference and so the relocation 
is 64-bit.

An attempt to parse such file, i.e. in DWARFContext::create, results in "failed 
to compute relocation" error.

This fix adds support for such relocations to RelocationResolver.cpp.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D67779

Patch by Oleg Pliss (Oleg.Pliss@azul.com)

llvm-svn: 372447
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arpilipe committed Sep 21, 2019
1 parent c96d554 commit 3e6590c45177958030513e6be199fc2d54f13ac7
Showing with 2 additions and 0 deletions.
  1. +2 −0 llvm/lib/Object/RelocationResolver.cpp
@@ -30,6 +30,7 @@ static bool supportsX86_64(uint64_t Type) {
case ELF::R_X86_64_DTPOFF32:
case ELF::R_X86_64_DTPOFF64:
case ELF::R_X86_64_PC32:
case ELF::R_X86_64_PC64:
case ELF::R_X86_64_32:
case ELF::R_X86_64_32S:
return true;
@@ -47,6 +48,7 @@ static uint64_t resolveX86_64(RelocationRef R, uint64_t S, uint64_t A) {
case ELF::R_X86_64_DTPOFF64:
return S + getELFAddend(R);
case ELF::R_X86_64_PC32:
case ELF::R_X86_64_PC64:
return S + getELFAddend(R) - R.getOffset();
case ELF::R_X86_64_32:
case ELF::R_X86_64_32S:

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