[lld] r250865 - Fix symbol value calculation in SHF_MERGE.

[Rafael Espindola via llvm-commits]

Author: rafael
Date: Tue Oct 20 17:08:49 2015
New Revision: 250865

URL: http://llvm.org/viewvc/llvm-project?rev=250865&view=rev
Log:
Fix symbol value calculation in SHF_MERGE.

We would get the wrong value if the symbol was in the middle of an entry.

Added:
    lld/trunk/test/elf2/merge-sym.s
Modified:
    lld/trunk/ELF/InputSection.cpp
    lld/trunk/ELF/OutputSections.cpp

Modified: lld/trunk/ELF/InputSection.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/InputSection.cpp?rev=250865&r1=250864&r2=250865&view=diff
==============================================================================
--- lld/trunk/ELF/InputSection.cpp (original)
+++ lld/trunk/ELF/InputSection.cpp Tue Oct 20 17:08:49 2015
@@ -134,10 +134,14 @@ typename MergeInputSection<ELFT>::uintX_
 MergeInputSection<ELFT>::getOffset(uintX_t Offset) const {
   ArrayRef<uint8_t> Data = this->getSectionData();
   uintX_t EntSize = this->Header->sh_entsize;
+  uintX_t Addend = Offset % EntSize;
+  Offset -= Addend;
   if (Offset + EntSize > Data.size())
     error("Entry is past the end of the section");
   Data = Data.slice(Offset, EntSize);
-  return static_cast<MergeOutputSection<ELFT> *>(this->OutSec)->getOffset(Data);
+  return static_cast<MergeOutputSection<ELFT> *>(this->OutSec)
+             ->getOffset(Data) +
+         Addend;
 }
 
 namespace lld {

Modified: lld/trunk/ELF/OutputSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/OutputSections.cpp?rev=250865&r1=250864&r2=250865&view=diff
==============================================================================
--- lld/trunk/ELF/OutputSections.cpp (original)
+++ lld/trunk/ELF/OutputSections.cpp Tue Oct 20 17:08:49 2015
@@ -530,8 +530,7 @@ lld::elf2::getLocalRelTarget(const Objec
   uintX_t Offset = Sym->st_value;
   if (Sym->getType() == STT_SECTION) {
     Offset += Addend;
-    Addend = Offset % Section->getSectionHdr()->sh_entsize;
-    Offset -= Addend;
+    Addend = 0;
   }
   return VA + cast<MergeInputSection<ELFT>>(Section)->getOffset(Offset) +
          Addend;

Added: lld/trunk/test/elf2/merge-sym.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf2/merge-sym.s?rev=250865&view=auto
==============================================================================
--- lld/trunk/test/elf2/merge-sym.s (added)
+++ lld/trunk/test/elf2/merge-sym.s Tue Oct 20 17:08:49 2015
@@ -0,0 +1,21 @@
+// REQUIRES: x86
+// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+// RUN: ld.lld2 %t.o -o %t.so -shared
+// RUN: llvm-readobj -t -s %t.so | FileCheck %s
+
+        .section        .rodata.cst4,"aM", at progbits,4
+        .short 0
+foo:
+        .short 42
+
+
+// CHECK:      Name: .rodata
+// CHECK-NEXT: Type: SHT_PROGBITS
+// CHECK-NEXT: Flags [
+// CHECK-NEXT:   SHF_ALLOC
+// CHECK-NEXT:   SHF_MERGE
+// CHECK-NEXT: ]
+// CHECK-NEXT: Address: 0x120
+
+// CHECK:      Name: foo
+// CHECK-NEXT: Value: 0x122