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Don't set dso_local flag in LTO resolutions for absolute symbols defined in ELF

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objects, it confuses codegen into generating pc-rel relocations for those
symbols, which leads to linker errors.

Differential Revision: https://reviews.llvm.org/D42977

llvm-svn: 324435
This commit is contained in:
Dmitry Mikulin 2018-02-07 00:49:51 +00:00
parent 532fa0e1ca
commit c84e0ee0e2
3 changed files with 23 additions and 1 deletions
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8
lld/ELF/LTO.cpp
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@ -154,8 +154,14 @@ void BitcodeCompiler::add(BitcodeFile &F) {
R.VisibleToRegularObj = Config->Relocatable || Sym->IsUsedInRegularObj ||
(R.Prevailing && Sym->includeInDynsym()) ||
UsedStartStop.count(ObjSym.getSectionName());
const auto *DR = dyn_cast<Defined>(Sym);
R.FinalDefinitionInLinkageUnit =
Sym->isDefined() && (IsExecutable || Sym->Visibility != STV_DEFAULT);
(IsExecutable || Sym->Visibility != STV_DEFAULT) && DR &&
// Skip absolute symbols from ELF objects, otherwise PC-rel relocations
// will be generated by for them, triggering linker errors.
// Symbol section is always null for bitcode symbols, hence the check
// for isElf().
!(Sym->File && Sym->File->isElf() && DR->Section == nullptr);
if (R.Prevailing)
undefine(Sym);

2
lld/test/ELF/lto/Inputs/absolute.s Normal file
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@ -0,0 +1,2 @@
.globl blah
blah = 0xdeadbeef

14
lld/test/ELF/lto/abs-resol.ll Normal file
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@ -0,0 +1,14 @@
; REQUIRES: x86
; RUN: llvm-as %s -o %t.o
; RUN: llvm-mc -triple=x86_64-pc-linux %p/Inputs/absolute.s -o %t2.o -filetype=obj
; RUN: ld.lld %t.o %t2.o -o %t.out -pie
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@blah = external global i8, align 1
define i8* @_start() {
ret i8* @blah
}