[XCOFF] Enable symbol alias for AIX

Summary:
AIX assembly's .set directive is not usable for aliasing purpose.
We need to use extra-label-at-defintion strategy to generate symbol
aliasing on AIX.

Reviewed By: DiggerLin, Xiangling_L

Differential Revision: https://reviews.llvm.org/D83252

1 files changed, 13 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 27bebe5..6531277 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -2125,9 +2125,11 @@ const MCExpr *TargetLoweringObjectFileXCOFF::lowerRelativeReference(
   report_fatal_error("XCOFF not yet implemented.");
 }
 
-XCOFF::StorageClass TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(
-    const GlobalObject *GO) {
-  switch (GO->getLinkage()) {
+XCOFF::StorageClass
+TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(const GlobalValue *GV) {
+  assert(!isa<GlobalIFunc>(GV) && "GlobalIFunc is not supported on AIX.");
+
+  switch (GV->getLinkage()) {
   case GlobalValue::InternalLinkage:
   case GlobalValue::PrivateLinkage:
     return XCOFF::C_HIDEXT;
@@ -2149,10 +2151,16 @@ XCOFF::StorageClass TargetLoweringObjectFileXCOFF::getStorageClassForGlobal(
 }
 
 MCSymbol *TargetLoweringObjectFileXCOFF::getFunctionEntryPointSymbol(
-    const Function *F, const TargetMachine &TM) const {
+    const GlobalValue *Func, const TargetMachine &TM) const {
+  assert(
+      isa<Function>(Func) ||
+      (isa<GlobalAlias>(Func) &&
+       isa_and_nonnull<Function>(cast<GlobalAlias>(Func)->getBaseObject())) &&
+          "Func must be a function or an alias which has a function as base "
+          "object.");
   SmallString<128> NameStr;
   NameStr.push_back('.');
-  getNameWithPrefix(NameStr, F, TM);
+  getNameWithPrefix(NameStr, Func, TM);
   return getContext().getOrCreateSymbol(NameStr);
 }