[AST] Fix the EndLoc calculation for ObjCObjectPointer

[lpetre]

Summary

There is an issue where the AST code does not compute the correct SourceRange for a ObjCObjectPointer.

From Richard Smith (ie @zygoloid) in discord:

I think the problem is that we set an invalid location for the * (because there isn't one): https://github.com/llvm/llvm-project/blob/main/clang/lib/Sema/SemaType.cpp#L1121
And then we use the default getLocalSourceRangeImpl for a PointerLikeTypeLoc that just assumes the * location is the type's end location: https://github.com/llvm/llvm-project/blob/main/clang/include/clang/AST/TypeLoc.h#L1293
Possibly we should be special-casing that here: https://github.com/llvm/llvm-project/blob/main/clang/lib/AST/TypeLoc.cpp#L228

My change:

• introduces a AST dump test to show the issue in the first commit
• special cases ObjCObjectPointerType in the second commit to correctly compute the end location

[lpetre]

Updating diff with full commit range

My initial arc diff only picked up the final commit, now running for all commits

[lpetre]

Trying again to include both commits

[aaron.ballman]

LGTM! Do you need someone to commit on your behalf? If so, let me know what name and email address you would like me to use for patch attribution and I can land it after giving a day or two for @rsmith to review.

[aaron.ballman]

I've commit on your behalf in a9db0a804a5335b6534995c54ab9d6fcef06e739, thank you for the fix!

[rsmith]

I think this is still not quite right: if the ObjCObjectPointerType has a valid star location, we should use that. We should only be falling back on the inner location's end when there is no star. For example:

@interface X @end;
using ObjectPointer = X*;

... should have an end loc that points at the *, not the X.

[rsmith]

In D112101#3097387, @rsmith wrote:

I think this is still not quite right

Fixed in rG68ffcd521347e3c8b97ca233239d503beff239f4.

[aaron.ballman]

In D112101#3097618, @rsmith wrote:

In D112101#3097387, @rsmith wrote:

I think this is still not quite right

Fixed in rG68ffcd521347e3c8b97ca233239d503beff239f4.

Thanks for the quick fix!

clang/lib/AST/TypeLoc.cpp

while (true) {
     case BlockPointer:
     case MemberPointer:
     case LValueReference:
     case RValueReference:
     case PackExpansion:
       if (!Last)
         Last = Cur;
       break;
+    case ObjCObjectPointer:
     case Qualified:
     case Elaborated:
       break;
     }
     Cur = Cur.getNextTypeLoc();
   }
 }
 

clang/test/AST/ast-dump-decl.mm

void f() {
     // CHECK-NEXT:     BlockExpr {{.*}} <col:5, col:22> 'void (^)()'
     // CHECK-NEXT:       BlockDecl {{.*}} <col:5, col:22> col:5 captures_this
     // CHECK-NEXT:         CompoundStmt {{.*}} <col:6, col:22>
     // CHECK-NEXT:           CXXMemberCallExpr {{.*}} <col:8, col:19> 'void'
     // CHECK-NEXT:             MemberExpr {{.*}} <col:8, col:14> '<bound member function type>' ->yada
     // CHECK-NEXT:               CXXThisExpr {{.*}} <col:8> 'Test *' this
   }
   void yada();
+  // CHECK:      CXXMethodDecl {{.*}} <line:[[@LINE-1]]:3, col:13> col:8 used yada 'void ()'
 };
+
+@protocol P
+@end;
+
+using TestAlias = id<P>;
+// CHECK:      TypeAliasDecl {{.+}} <{{.+}}:[[@LINE-1]]:1, col:23> col:7 TestAlias 'id<P>'