Fix address space for function pointers with qualifier

This patch fixes a bug introduced in commit 4eaf5846d0. Commit
4eaf5846d0 sets address space of function type as program
address space unconditionally. This breaks types which have
address space qualifiers. E.g. __ptr32.

This patch fixes the bug by using address space qualifiers if
present.

Differential Revision: https://reviews.llvm.org/D119045

clang/lib/AST/ASTContext.cpp

@@ -11959,8 +11959,13 @@ uint64_t ASTContext::getTargetNullPointerValue(QualType QT) const {
 }
 
 unsigned ASTContext::getTargetAddressSpace(QualType T) const {
-  return T->isFunctionType() ? getTargetInfo().getProgramAddressSpace()
-                             : getTargetAddressSpace(T.getQualifiers());
+  // Return the address space for the type. If the type is a
+  // function type without an address space qualifier, the
+  // program address space is used. Otherwise, the target picks
+  // the best address space based on the type information
+  return T->isFunctionType() && !T.hasAddressSpace()
+             ? getTargetInfo().getProgramAddressSpace()
+             : getTargetAddressSpace(T.getQualifiers());
 }
 
 unsigned ASTContext::getTargetAddressSpace(Qualifiers Q) const {

clang/test/CodeGen/address-space-ptr32.c

@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -triple x86_64-windows-msvc -fms-extensions -emit-llvm < %s | FileCheck %s
+
+int foo(void) {
+  int (*__ptr32 a)(int);
+  return sizeof(a);
+}
+
+// CHECK: define dso_local i32 @foo
+// CHECK: %a = alloca i32 (i32) addrspace(270)*, align 4
+// CHECK: ret i32 4