[TypeSystem] Fix inspection of Objective-C object types

ptr_refs exposed a problem in ClangASTContext's implementation: it
uses an accessor to downcast a QualType to an
ObjCObjectPointerType, but the accessor is not fully general.
getAs() is the safer way to go.

I've added a test case that uses ptr_refs in a way that would
crash before the fix.

<rdar://problem/31363513>


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@303110 91177308-0d34-0410-b5e6-96231b3b80d8

Author: scallanan

packages/Python/lldbsuite/test/lang/objc/ptr_refs/Makefile

@@ -0,0 +1,5 @@
+LEVEL = ../../../make
+
+OBJC_SOURCES := main.m
+
+include $(LEVEL)/Makefile.rules

packages/Python/lldbsuite/test/lang/objc/ptr_refs/TestPtrRefsObjC.py

@@ -0,0 +1,50 @@
+"""
+Test the ptr_refs tool on Darwin with Objective-C
+"""
+
+from __future__ import print_function
+
+import os
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class TestPtrRefsObjC(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @skipUnlessDarwin
+    def test_ptr_refs(self):
+        """Test the ptr_refs tool on Darwin with Objective-C"""
+        self.build()
+        exe_name = 'a.out'
+        exe = os.path.join(os.getcwd(), exe_name)
+
+        target = self.dbg.CreateTarget(exe)
+        self.assertTrue(target, VALID_TARGET)
+
+        main_file_spec = lldb.SBFileSpec('main.m')
+        breakpoint = target.BreakpointCreateBySourceRegex(
+            'break', main_file_spec)
+        self.assertTrue(breakpoint and
+                        breakpoint.GetNumLocations() == 1,
+                        VALID_BREAKPOINT)
+
+        process = target.LaunchSimple(
+            None, None, self.get_process_working_directory())
+        self.assertTrue(process, PROCESS_IS_VALID)
+
+        # Frame #0 should be on self.line1 and the break condition should hold.
+        thread = lldbutil.get_stopped_thread(
+            process, lldb.eStopReasonBreakpoint)
+        self.assertTrue(
+            thread.IsValid(),
+            "There should be a thread stopped due to breakpoint condition")
+
+        frame = thread.GetFrameAtIndex(0)
+
+        self.dbg.HandleCommand("script import lldb.macosx.heap")
+        self.expect("ptr_refs self", substrs=["malloc", "stack"])
+

packages/Python/lldbsuite/test/lang/objc/ptr_refs/main.m

@@ -0,0 +1,39 @@
+//===-- main.c --------------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#import <Foundation/Foundation.h>
+
+@interface MyClass : NSObject {
+};
+-(void)test;
+@end
+
+@implementation MyClass
+-(void)test {
+    printf("%p\n", self); // break here
+}
+@end
+
+@interface MyOwner : NSObject {
+  @public id ownedThing; // should be id, to test <rdar://problem/31363513>
+};
+@end
+
+@implementation MyOwner
+@end
+
+int main (int argc, char const *argv[]) {
+    @autoreleasepool {
+        MyOwner *owner = [[MyOwner alloc] init];
+        owner->ownedThing = [[MyClass alloc] init];
+        [(MyClass*)owner->ownedThing test];
+    }
+    return 0;
+}
+

source/Symbol/ClangASTContext.cpp

@@ -4551,7 +4551,7 @@ ClangASTContext::GetNumMemberFunctions(lldb::opaque_compiler_type_t type) {
 
     case clang::Type::ObjCObjectPointer: {
       const clang::ObjCObjectPointerType *objc_class_type =
-          qual_type->getAsObjCInterfacePointerType();
+          qual_type->getAs<clang::ObjCObjectPointerType>();
       const clang::ObjCInterfaceType *objc_interface_type =
           objc_class_type->getInterfaceType();
       if (objc_interface_type &&
@@ -4659,7 +4659,7 @@ ClangASTContext::GetMemberFunctionAtIndex(lldb::opaque_compiler_type_t type,
 
     case clang::Type::ObjCObjectPointer: {
       const clang::ObjCObjectPointerType *objc_class_type =
-          qual_type->getAsObjCInterfacePointerType();
+          qual_type->getAs<clang::ObjCObjectPointerType>();
       const clang::ObjCInterfaceType *objc_interface_type =
           objc_class_type->getInterfaceType();
       if (objc_interface_type &&
@@ -5766,7 +5766,7 @@ uint32_t ClangASTContext::GetNumFields(lldb::opaque_compiler_type_t type) {
 
   case clang::Type::ObjCObjectPointer: {
     const clang::ObjCObjectPointerType *objc_class_type =
-        qual_type->getAsObjCInterfacePointerType();
+        qual_type->getAs<clang::ObjCObjectPointerType>();
     const clang::ObjCInterfaceType *objc_interface_type =
         objc_class_type->getInterfaceType();
     if (objc_interface_type &&
@@ -5913,7 +5913,7 @@ CompilerType ClangASTContext::GetFieldAtIndex(lldb::opaque_compiler_type_t type,
 
   case clang::Type::ObjCObjectPointer: {
     const clang::ObjCObjectPointerType *objc_class_type =
-        qual_type->getAsObjCInterfacePointerType();
+        qual_type->getAs<clang::ObjCObjectPointerType>();
     const clang::ObjCInterfaceType *objc_interface_type =
         objc_class_type->getInterfaceType();
     if (objc_interface_type &&