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ELF: Allow ICF on .data.rel.ro sections. 

Differential Revision: https://reviews.llvm.org/D47234

llvm-svn: 333040
This commit is contained in:
Peter Collingbourne 2018-05-22 23:22:35 +00:00
parent 3ef8f858da
commit 3a9e2ca051
2 changed files with 19 additions and 2 deletions
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9
lld/ELF/ICF.cpp
View File

@ -162,8 +162,13 @@ template <class ELFT> static uint32_t getHash(InputSection *S) {
// Returns true if section S is subject of ICF.
static bool isEligible(InputSection *S) {
if (!S->Live || S->KeepUnique || !(S->Flags & SHF_ALLOC) ||
(S->Flags & SHF_WRITE))
if (!S->Live || S->KeepUnique || !(S->Flags & SHF_ALLOC))
return false;
// Don't merge writable sections. .data.rel.ro sections are marked as writable
// but are semantically read-only.
if ((S->Flags & SHF_WRITE) && S->Name != ".data.rel.ro" &&
!S->Name.startswith(".data.rel.ro."))
return false;
// Don't merge read only data sections unless

12
lld/test/ELF/icf-relro.s Normal file
View File

@ -0,0 +1,12 @@
# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
# RUN: ld.lld %t -o %t2 --icf=all --ignore-data-address-equality --print-icf-sections | FileCheck %s
# CHECK: selected section {{.*}}:(.data.rel.ro)
# CHECK: removing identical section {{.*}}:(.data.rel.ro.foo)
.section .data.rel.ro,"aw"
.quad foo
.section .data.rel.ro.foo,"aw"
foo:
.quad foo