[clang] [clang][CodeGen] Make `UnqualPtrTy` truly unqualified (PR #94388)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-codegen

@llvm/pr-subscribers-clang

Author: Alex Voicu (AlexVlx)

<details>
<summary>Changes</summary>

At the moment we alias `UnqualPtrTy` with the other default AS pointer types, which means that for certain targets using it doesn't actually yield an unqualified pointer. This patch changes that so that it does exactly what it says on the tin, under the assumption that if someone asks for an unqualified pointer they do so knowingly and expect to get exactly that.

---
Full diff: https://github.com/llvm/llvm-project/pull/94388.diff


3 Files Affected:

- (modified) clang/lib/CodeGen/CodeGenModule.cpp (+1) 
- (modified) clang/lib/CodeGen/CodeGenTypeCache.h (+3-1) 
- (modified) clang/lib/CodeGen/ItaniumCXXABI.cpp (+3-3) 


``````````diff
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index be7bf0b72dc0c..b58ca03ce69da 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -368,6 +368,7 @@ CodeGenModule::CodeGenModule(ASTContext &C,
   IntTy = llvm::IntegerType::get(LLVMContext, C.getTargetInfo().getIntWidth());
   IntPtrTy = llvm::IntegerType::get(LLVMContext,
     C.getTargetInfo().getMaxPointerWidth());
+  UnqualPtrTy = llvm::PointerType::getUnqual(LLVMContext);
   Int8PtrTy = llvm::PointerType::get(LLVMContext,
                                      C.getTargetAddressSpace(LangAS::Default));
   const llvm::DataLayout &DL = M.getDataLayout();
diff --git a/clang/lib/CodeGen/CodeGenTypeCache.h b/clang/lib/CodeGen/CodeGenTypeCache.h
index e273ebe3b060f..3b659bc182aa4 100644
--- a/clang/lib/CodeGen/CodeGenTypeCache.h
+++ b/clang/lib/CodeGen/CodeGenTypeCache.h
@@ -51,9 +51,11 @@ struct CodeGenTypeCache {
     llvm::IntegerType *PtrDiffTy;
   };
 
+  /// unqualified void*
+  llvm::PointerType *UnqualPtrTy;
+
   /// void*, void** in the target's default address space (often 0)
   union {
-    llvm::PointerType *UnqualPtrTy;
     llvm::PointerType *VoidPtrTy;
     llvm::PointerType *Int8PtrTy;
     llvm::PointerType *VoidPtrPtrTy;
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index 8427286dee887..8952e7ca072da 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -4656,14 +4656,14 @@ static void InitCatchParam(CodeGenFunction &CGF,
   auto catchRD = CatchType->getAsCXXRecordDecl();
   CharUnits caughtExnAlignment = CGF.CGM.getClassPointerAlignment(catchRD);
 
-  llvm::Type *PtrTy = CGF.UnqualPtrTy; // addrspace 0 ok
+  llvm::Type *PtrTy = CGF.UnqualPtrTy; // unqualified is ok
 
   // Check for a copy expression.  If we don't have a copy expression,
   // that means a trivial copy is okay.
   const Expr *copyExpr = CatchParam.getInit();
   if (!copyExpr) {
     llvm::Value *rawAdjustedExn = CallBeginCatch(CGF, Exn, true);
-    Address adjustedExn(CGF.Builder.CreateBitCast(rawAdjustedExn, PtrTy),
+    Address adjustedExn(CGF.Builder.CreatePointerCast(rawAdjustedExn, PtrTy),
                         LLVMCatchTy, caughtExnAlignment);
     LValue Dest = CGF.MakeAddrLValue(ParamAddr, CatchType);
     LValue Src = CGF.MakeAddrLValue(adjustedExn, CatchType);
@@ -4677,7 +4677,7 @@ static void InitCatchParam(CodeGenFunction &CGF,
     CGF.EmitNounwindRuntimeCall(getGetExceptionPtrFn(CGF.CGM), Exn);
 
   // Cast that to the appropriate type.
-  Address adjustedExn(CGF.Builder.CreateBitCast(rawAdjustedExn, PtrTy),
+  Address adjustedExn(CGF.Builder.CreatePointerCast(rawAdjustedExn, PtrTy),
                       LLVMCatchTy, caughtExnAlignment);
 
   // The copy expression is defined in terms of an OpaqueValueExpr.

``````````

</details>


https://github.com/llvm/llvm-project/pull/94388