[clang] 956582a - [Sema] Iteratively strip sugar when removing address spaces.

[Bevin Hansson via cfe-commits]

Author: Bevin Hansson
Date: 2020-08-11T17:26:19+02:00
New Revision: 956582aa165804dd8335879c3a7f833901e5424c

URL: https://github.com/llvm/llvm-project/commit/956582aa165804dd8335879c3a7f833901e5424c
DIFF: https://github.com/llvm/llvm-project/commit/956582aa165804dd8335879c3a7f833901e5424c.diff

LOG: [Sema] Iteratively strip sugar when removing address spaces.

ASTContext::removeAddrSpaceQualType does not properly deal
with sugar. QualTypes derive their ASes from the AS on the
canonical type, not the type itself. However,
removeAddrSpaceQualType only strips the outermost qualifiers,
which means that it can fail to remove addrspace qualifiers
if there is sugar in the way.

Change the function to desugar types until the address space
really no longer exists on the corresponding QualType. This
should guarantee the removal of the address space.

This fixes the erroneous behavior in D62574.

Reviewed By: rjmccall, svenvh

Differential Revision: https://reviews.llvm.org/D83325

Added: 
    

Modified: 
    clang/lib/AST/ASTContext.cpp
    clang/test/CodeGenCXX/address-space-cast.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 7947de3a31fc..4d708d57cabf 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -2934,14 +2934,27 @@ QualType ASTContext::getAddrSpaceQualType(QualType T,
 }
 
 QualType ASTContext::removeAddrSpaceQualType(QualType T) const {
+  // If the type is not qualified with an address space, just return it
+  // immediately.
+  if (!T.hasAddressSpace())
+    return T;
+
   // If we are composing extended qualifiers together, merge together
   // into one ExtQuals node.
   QualifierCollector Quals;
-  const Type *TypeNode = Quals.strip(T);
+  const Type *TypeNode;
 
-  // If the qualifier doesn't have an address space just return it.
-  if (!Quals.hasAddressSpace())
-    return T;
+  while (T.hasAddressSpace()) {
+    TypeNode = Quals.strip(T);
+
+    // If the type no longer has an address space after stripping qualifiers,
+    // jump out.
+    if (!QualType(TypeNode, 0).hasAddressSpace())
+      break;
+
+    // There might be sugar in the way. Strip it and try again.
+    T = T.getSingleStepDesugaredType(*this);
+  }
 
   Quals.removeAddressSpace();
 

diff  --git a/clang/test/CodeGenCXX/address-space-cast.cpp b/clang/test/CodeGenCXX/address-space-cast.cpp
index e0cf3c199b88..7b0792df8588 100644
--- a/clang/test/CodeGenCXX/address-space-cast.cpp
+++ b/clang/test/CodeGenCXX/address-space-cast.cpp
@@ -6,6 +6,16 @@ void func_pchar(__private__ char *x);
 void func_pvoid(__private__ void *x);
 void func_pint(__private__ int *x);
 
+class Base {
+};
+
+class Derived : public Base {
+};
+
+void fn(Derived *p) {
+  __private__ Base *b = (__private__ Base *)p;
+}
+
 void test_cast(char *gen_char_ptr, void *gen_void_ptr, int *gen_int_ptr) {
   // CHECK: %[[cast:.*]] = addrspacecast i8* %{{.*}} to i8 addrspace(5)*
   // CHECK-NEXT: store i8 addrspace(5)* %[[cast]]