[IR] Add method to GlobalVariable to change type of initializer. (#102553)

With opaque pointers, nothing directly uses the value type, so we can
mutate it if we want. This avoid doing a complicated RAUW dance.

1 files changed, 1 insertions, 27 deletions

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 882dbad..563f728 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -370,38 +370,12 @@ CodeGenFunction::AddInitializerToStaticVarDecl(const VarDecl &D,
   assert(VarSize == CstSize && "Emitted constant has unexpected size");
 #endif
 
-  // The initializer may differ in type from the global. Rewrite
-  // the global to match the initializer.  (We have to do this
-  // because some types, like unions, can't be completely represented
-  // in the LLVM type system.)
-  if (GV->getValueType() != Init->getType()) {
-    llvm::GlobalVariable *OldGV = GV;
-
-    GV = new llvm::GlobalVariable(
-        CGM.getModule(), Init->getType(), OldGV->isConstant(),
-        OldGV->getLinkage(), Init, "",
-        /*InsertBefore*/ OldGV, OldGV->getThreadLocalMode(),
-        OldGV->getType()->getPointerAddressSpace());
-    GV->setVisibility(OldGV->getVisibility());
-    GV->setDSOLocal(OldGV->isDSOLocal());
-    GV->setComdat(OldGV->getComdat());
-
-    // Steal the name of the old global
-    GV->takeName(OldGV);
-
-    // Replace all uses of the old global with the new global
-    OldGV->replaceAllUsesWith(GV);
-
-    // Erase the old global, since it is no longer used.
-    OldGV->eraseFromParent();
-  }
-
   bool NeedsDtor =
       D.needsDestruction(getContext()) == QualType::DK_cxx_destructor;
 
   GV->setConstant(
       D.getType().isConstantStorage(getContext(), true, !NeedsDtor));
-  GV->setInitializer(Init);
+  GV->replaceInitializer(Init);
 
   emitter.finalize(GV);