[PATCH] D53993: [ELF] Change sh_link of .rel{, a}.plt to make GNU strip happy

[Fangrui Song via Phabricator via llvm-commits]

MaskRay updated this revision to Diff 172243.
MaskRay retitled this revision from "[ELF] Set sh_link to 0 in static link to make GNU strip happy" to "[ELF] Change sh_link of .rel{,a}.plt to make GNU strip happy".
MaskRay edited the summary of this revision.
MaskRay added a comment.

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Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D53993

Files:
  ELF/SyntheticSections.cpp
  test/ELF/aarch64-gnu-ifunc.s
  test/ELF/gnu-ifunc-i386.s
  test/ELF/gnu-ifunc.s


Index: test/ELF/gnu-ifunc.s
===================================================================
--- test/ELF/gnu-ifunc.s
+++ test/ELF/gnu-ifunc.s
@@ -15,16 +15,13 @@
 // CHECK-NEXT:  Address: [[RELA:.*]]
 // CHECK-NEXT:  Offset: 0x158
 // CHECK-NEXT:  Size: 48
-// CHECK-NEXT:  Link: [[SYMTAB:.*]]
+// CHECK-NEXT:  Link: 0
 // CHECK-NEXT:  Info: [[GOTPLT:.*]]
 // CHECK-NEXT:  AddressAlignment: 8
 // CHECK-NEXT:  EntrySize: 24
 // CHECK-NEXT: }
 // CHECK:      Index: [[GOTPLT]]
 // CHECK-NEXT: Name: .got.plt
-// CHECK:      Index: [[SYMTAB]]
-// CHECK-NEXT: Name: .symtab
-// CHECK-NEXT: Type: SHT_SYMTAB
 // CHECK:      Relocations [
 // CHECK-NEXT:   Section ({{.*}}) .rela.plt {
 // CHECK-NEXT:     0x202000 R_X86_64_IRELATIVE
Index: test/ELF/gnu-ifunc-i386.s
===================================================================
--- test/ELF/gnu-ifunc-i386.s
+++ test/ELF/gnu-ifunc-i386.s
@@ -15,7 +15,7 @@
 // CHECK-NEXT:  Address: [[RELA:.*]]
 // CHECK-NEXT:  Offset: 0xD4
 // CHECK-NEXT:  Size: 16
-// CHECK-NEXT:  Link: 6
+// CHECK-NEXT:  Link: 0
 // CHECK-NEXT:  Info: 4
 // CHECK-NEXT:  AddressAlignment: 4
 // CHECK-NEXT:  EntrySize: 8
Index: test/ELF/aarch64-gnu-ifunc.s
===================================================================
--- test/ELF/aarch64-gnu-ifunc.s
+++ test/ELF/aarch64-gnu-ifunc.s
@@ -15,7 +15,7 @@
 // CHECK-NEXT:  Address: [[RELA:.*]]
 // CHECK-NEXT:  Offset: 0x158
 // CHECK-NEXT:  Size: 48
-// CHECK-NEXT:  Link: 6
+// CHECK-NEXT:  Link: 0
 // CHECK-NEXT:  Info: 4
 // CHECK-NEXT:  AddressAlignment: 8
 // CHECK-NEXT:  EntrySize: 24
Index: ELF/SyntheticSections.cpp
===================================================================
--- ELF/SyntheticSections.cpp
+++ ELF/SyntheticSections.cpp
@@ -1491,13 +1491,11 @@
 }
 
 void RelocationBaseSection::finalizeContents() {
-  // If all relocations are R_*_{,I}RELATIVE they don't refer to any dynamic
-  // symbol and we don't need a dynamic symbol table. If that is the case, use
-  // the index of the regular symbol table section (if exists) or 0.
-  if (In.DynSymTab)
-    getParent()->Link = In.DynSymTab->getParent()->SectionIndex;
-  else if (In.SymTab)
-    getParent()->Link = In.SymTab->getParent()->SectionIndex;
+  // When linking glibc statically, .rel{,a}.plt contains R_*_IRELATIVE
+  // relocations due to IFUNC (e.g. strcpy). sh_link will be set to 0 in that
+  // case.
+  if (InputSection *SymTab = Config->Relocatable ? In.SymTab : In.DynSymTab)
+    getParent()->Link = SymTab->getParent()->SectionIndex;
   else
     getParent()->Link = 0;
 


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