[PATCH] D33763: [ELF] - Assign SHF_INFO_LINK flag to REL[A] sections.

[George Rimar via Phabricator via llvm-commits]

grimar created this revision.
Herald added a subscriber: emaste.

Spec says: (http://www.sco.com/developers/gabi/latest/ch4.sheader.html)

sh_info
This member holds extra information, whose interpretation depends on the section type. A table below describes the values. 
**If the sh_flags field for this section header includes the attribute SHF_INFO_LINK, then this member represents a section header table index.**

SHF_INFO_LINK
The sh_info field of this section header holds a section header table index.

Since sh_info for SHT_REL[A] sections should contain the section header index of the section to which the relocation applies, this is
consistent with spec to put this flag. Behavior matches both bfd and gold as well.


https://reviews.llvm.org/D33763

Files:
  ELF/OutputSections.cpp
  test/ELF/emit-relocs.s


Index: test/ELF/emit-relocs.s
===================================================================
--- test/ELF/emit-relocs.s
+++ test/ELF/emit-relocs.s
@@ -1,7 +1,7 @@
 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t1.o
 # RUN: ld.lld --emit-relocs %t1.o -o %t
-# RUN: llvm-readobj -t -r %t | FileCheck %s
+# RUN: llvm-readobj -t -r -s %t | FileCheck %s
 
 ## Check single dash form.
 # RUN: ld.lld -emit-relocs %t1.o -o %t1
@@ -11,6 +11,13 @@
 # RUN: ld.lld -q %t1.o -o %t2
 # RUN: llvm-readobj -t -r %t2 | FileCheck %s
 
+# CHECK:      Section {
+# CHECK:        Index: 2
+# CHECK-NEXT:   Name: .rela.text
+# CHECK-NEXT:   Type: SHT_RELA
+# CHECK-NEXT:   Flags [
+# CHECK-NEXT:     SHF_INFO_LINK
+# CHECK-NEXT:   ]
 # CHECK:      Relocations [
 # CHECK-NEXT:   Section ({{.*}}) .rela.text {
 # CHECK-NEXT:     0x201002 R_X86_64_32 .text 0x1
Index: ELF/OutputSections.cpp
===================================================================
--- ELF/OutputSections.cpp
+++ ELF/OutputSections.cpp
@@ -156,6 +156,7 @@
   // the section to which the relocation applies.
   InputSectionBase *S = First->getRelocatedSection();
   Info = S->getOutputSection()->SectionIndex;
+  Flags |= SHF_INFO_LINK;
 }
 
 static uint64_t updateOffset(uint64_t Off, InputSection *S) {


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