Append |.get()| to: auto* var_ptr = my_struct.ptr_field;

Bug: 1069567
Change-Id: Ie1b48c0a6ee3ed66213b59827dc77ef7d57d9a45
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2156069
Commit-Queue: Łukasz Anforowicz <lukasza@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#774879}

tools/clang/rewrite_raw_ptr_fields/RewriteRawPtrFields.cpp

@@ -529,6 +529,20 @@ int main(int argc, const char* argv[]) {
   match_finder.addMatcher(affected_ternary_operator_arg_matcher,
                           &affected_expr_rewriter);
 
+  // |auto| type declarations =========
+  // Given
+  //   struct S { int* y; };
+  //   void foo(const S& s) {
+  //     auto* p = s.y;
+  //   }
+  // binds the |s.y| expr if it matches the |affected_expr_matcher| above.
+  auto auto_var_decl_matcher = declStmt(forEach(varDecl(
+      allOf(hasType(pointerType(pointee(autoType()))),
+            hasInitializer(anyOf(
+                affected_implicit_expr_matcher,
+                initListExpr(hasInit(0, affected_implicit_expr_matcher))))))));
+  match_finder.addMatcher(auto_var_decl_matcher, &affected_expr_rewriter);
+
   // Prepare and run the tool.
   std::unique_ptr<clang::tooling::FrontendActionFactory> factory =
       clang::tooling::newFrontendActionFactory(&match_finder,

tools/clang/rewrite_raw_ptr_fields/tests/affected-expr-expected.cc

@@ -13,8 +13,79 @@ struct MyStruct {
   CheckedPtr<SomeClass> ptr;
   CheckedPtr<SomeClass> ptr2;
   CheckedPtr<const SomeClass> const_ptr;
+  int (*func_ptr_field)();
 };
 
+namespace auto_tests {
+
+MyStruct* GetMyStruct() {
+  return nullptr;
+}
+
+SomeClass* GetSomeClass() {
+  return nullptr;
+}
+
+SomeClass* ConvertSomeClassToSomeClass(SomeClass* some_class) {
+  return some_class;
+}
+
+void foo() {
+  MyStruct my_struct;
+
+  // After the rewrite |my_struct.ptr_field| is no longer a pointer,
+  // so |auto*| won't work.  We fix this up, by appending |.get()|.
+  // Expected rewrite: auto* ptr_var = my_struct.ptr.get();
+  auto* ptr_var = my_struct.ptr.get();
+
+  // Tests for other kinds of initialization.
+  // Expected rewrite: |.get()| should be appended in both cases below.
+  auto* init_test1(my_struct.ptr.get());
+  auto* init_test2{my_struct.ptr.get()};
+
+  // Test for handling of the |const| qualifier.
+  // Expected rewrite: const auto* ptr_var = my_struct.ptr.get();
+  const auto* const_ptr_var = my_struct.ptr.get();
+
+  // More complicated initialization expression, but the |ptr_field| struct
+  // member dereference is still the top/last expression here.
+  // Expected rewrite: ...->ptr.get()
+  auto* complicated_var = GetMyStruct()->ptr.get();
+
+  // The test below covers:
+  // 1. Two variables with single |auto|,
+  // 2. Tricky placement of |*| (next to the variable name).
+  // Expected rewrite: ...ptr.get()... (twice in the 2nd example).
+  auto *ptr_var1 = my_struct.ptr.get(), *ptr_var2 = GetSomeClass();
+  auto *ptr_var3 = my_struct.ptr.get(), *ptr_var4 = my_struct.ptr.get();
+  auto *ptr_var5 = GetSomeClass(), *ptr_var6 = my_struct.ptr.get();
+
+  // Test for the case where
+  // 1. The resulting type is the same as in the |ptr_var| and |complicated_var|
+  //    examples
+  // 2. Deep in the initialization expression there is a member dereference
+  //    of |ptr_field|
+  // but
+  // 3. The final/top-level initialization expression doesn't dereference
+  //    |ptr_field|.
+  // No rewrite expected.
+  auto* not_affected_field_var = ConvertSomeClassToSomeClass(my_struct.ptr);
+
+  // Test for pointer |auto| assigned from non-CheckedPtr-elligible field.
+  // No rewrite expected.
+  auto* func_ptr_var = my_struct.func_ptr_field;
+
+  // Test for non-pointer |auto| assigned from CheckedPtr-elligible field.
+  // No rewrite expected.
+  auto non_pointer_auto_var = my_struct.ptr;
+
+  // Test for non-auto pointer.
+  // No rewrite expected.
+  SomeClass* non_auto_ptr_var = my_struct.ptr;
+}
+
+}  // namespace auto_tests
+
 namespace printf_tests {
 
 int ConvertSomeClassToInt(SomeClass* some_class) {

tools/clang/rewrite_raw_ptr_fields/tests/affected-expr-original.cc

@@ -11,8 +11,79 @@ struct MyStruct {
   SomeClass* ptr;
   SomeClass* ptr2;
   const SomeClass* const_ptr;
+  int (*func_ptr_field)();
 };
 
+namespace auto_tests {
+
+MyStruct* GetMyStruct() {
+  return nullptr;
+}
+
+SomeClass* GetSomeClass() {
+  return nullptr;
+}
+
+SomeClass* ConvertSomeClassToSomeClass(SomeClass* some_class) {
+  return some_class;
+}
+
+void foo() {
+  MyStruct my_struct;
+
+  // After the rewrite |my_struct.ptr_field| is no longer a pointer,
+  // so |auto*| won't work.  We fix this up, by appending |.get()|.
+  // Expected rewrite: auto* ptr_var = my_struct.ptr.get();
+  auto* ptr_var = my_struct.ptr;
+
+  // Tests for other kinds of initialization.
+  // Expected rewrite: |.get()| should be appended in both cases below.
+  auto* init_test1(my_struct.ptr);
+  auto* init_test2{my_struct.ptr};
+
+  // Test for handling of the |const| qualifier.
+  // Expected rewrite: const auto* ptr_var = my_struct.ptr.get();
+  const auto* const_ptr_var = my_struct.ptr;
+
+  // More complicated initialization expression, but the |ptr_field| struct
+  // member dereference is still the top/last expression here.
+  // Expected rewrite: ...->ptr.get()
+  auto* complicated_var = GetMyStruct()->ptr;
+
+  // The test below covers:
+  // 1. Two variables with single |auto|,
+  // 2. Tricky placement of |*| (next to the variable name).
+  // Expected rewrite: ...ptr.get()... (twice in the 2nd example).
+  auto *ptr_var1 = my_struct.ptr, *ptr_var2 = GetSomeClass();
+  auto *ptr_var3 = my_struct.ptr, *ptr_var4 = my_struct.ptr;
+  auto *ptr_var5 = GetSomeClass(), *ptr_var6 = my_struct.ptr;
+
+  // Test for the case where
+  // 1. The resulting type is the same as in the |ptr_var| and |complicated_var|
+  //    examples
+  // 2. Deep in the initialization expression there is a member dereference
+  //    of |ptr_field|
+  // but
+  // 3. The final/top-level initialization expression doesn't dereference
+  //    |ptr_field|.
+  // No rewrite expected.
+  auto* not_affected_field_var = ConvertSomeClassToSomeClass(my_struct.ptr);
+
+  // Test for pointer |auto| assigned from non-CheckedPtr-elligible field.
+  // No rewrite expected.
+  auto* func_ptr_var = my_struct.func_ptr_field;
+
+  // Test for non-pointer |auto| assigned from CheckedPtr-elligible field.
+  // No rewrite expected.
+  auto non_pointer_auto_var = my_struct.ptr;
+
+  // Test for non-auto pointer.
+  // No rewrite expected.
+  SomeClass* non_auto_ptr_var = my_struct.ptr;
+}
+
+}  // namespace auto_tests
+
 namespace printf_tests {
 
 int ConvertSomeClassToInt(SomeClass* some_class) {