CodeGen: Allow !associated metadata to point to aliases.

This is a small extension of !associated, mostly useful for the implementation
convenience of instrumentation passes that RAUW globals with aliases, such
as LowerTypeTests.

Differential Revision: https://reviews.llvm.org/D64951

llvm-svn: 366502

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 4c8f75b..23cb1c1 100644 (file)
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -524,8 +524,8 @@ static const MCSymbolELF *getAssociatedSymbol(const GlobalObject *GO,
   if (!VM)
     report_fatal_error("MD_associated operand is not ValueAsMetadata");
 
-  GlobalObject *OtherGO = dyn_cast<GlobalObject>(VM->getValue());
-  return OtherGO ? dyn_cast<MCSymbolELF>(TM.getSymbol(OtherGO)) : nullptr;
+  auto *OtherGV = dyn_cast<GlobalValue>(VM->getValue());
+  return OtherGV ? dyn_cast<MCSymbolELF>(TM.getSymbol(OtherGV)) : nullptr;
 }
 
 static unsigned getEntrySizeForKind(SectionKind Kind) {

diff --git a/llvm/test/CodeGen/X86/elf-associated.ll b/llvm/test/CodeGen/X86/elf-associated.ll
index 7d58c34..e0e9e00 100644 (file)
--- a/llvm/test/CodeGen/X86/elf-associated.ll
+++ b/llvm/test/CodeGen/X86/elf-associated.ll
@@ -33,7 +33,7 @@
 ; CHECK-DAG: .section  bbb,"awo",@progbits,h,unique,2
 ; CHECK-DAG: .section  .data.k,"awo",@progbits,h
 
-; Non-GlobalObject metadata.
+; Non-GlobalValue metadata.
 @l = global i32 1, section "ccc", !associated !5
 !5 = !{i32* null}
 ; CHECK-DAG: .section  ccc,"aw",@progbits
@@ -42,3 +42,9 @@
 @m = global i32 1, section "ddd", !associated !6
 !6 = distinct !{null}
 ; CHECK-DAG: .section  ddd,"aw",@progbits
+
+; Aliases are OK.
+@n = alias i32, i32* inttoptr (i64 add (i64 ptrtoint (i32* @a to i64), i64 1297036692682702848) to i32*)
+@o = global i32 1, section "eee", !associated !7
+!7 = !{i32* @n}
+; CHECK-DAG: .section  eee,"awo",@progbits,n,unique,3