ELF/AMDGPU: Add support for R_AMDGPU_REL32 relocations

Reviewers: rafael, ruiu

Subscribers: kzhuravl, llvm-commits

Differential Revision: http://reviews.llvm.org/D21294

llvm-svn: 273192

lld/ELF/Target.cpp

@@ -1405,17 +1405,16 @@ void AArch64TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type,
   llvm_unreachable("invalid relocation for TLS IE to LE relaxation");
 }
 
-// Implementing relocations for AMDGPU is low priority since most
-// programs don't use relocations now. Thus, this function is not
-// actually called (relocateOne is called for each relocation).
-// That's why the AMDGPU port works without implementing this function.
 void AMDGPUTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type,
                                    uint64_t Val) const {
-  llvm_unreachable("not implemented");
+  assert(Type == R_AMDGPU_REL32);
+  write32le(Loc, Val);
 }
 
 RelExpr AMDGPUTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const {
-  llvm_unreachable("not implemented");
+  if (Type != R_AMDGPU_REL32)
+    error("do not know how to handle relocation");
+  return R_PC;
 }
 
 ARMTargetInfo::ARMTargetInfo() {

lld/test/ELF/amdgpu-relocs.s

@@ -0,0 +1,18 @@
+# RUN: llvm-mc -filetype=obj -triple=amdgcn--amdhsa -mcpu=fiji %s -o %t.o
+# RUN: ld.lld -shared %t.o -o %t.so
+# RUN: llvm-readobj -r %t.so | FileCheck %s
+
+# REQUIRES: amdgpu
+
+# Make sure that the reloc for local_var is resolved by lld.
+
+  .text
+
+kernel0:
+  s_mov_b32 s0, local_var+4
+  s_endpgm
+
+  .local local_var
+
+# CHECK: Relocations [
+# CHECK-NEXT: ]