Suggest automated replacements of C-style casts with C++ casts.

Summary:
This patch implements a subset of possible replacements of C-style
casts with const_cast/static_cast/reinterpret_cast. This should cover a large
portion of cases in real code. Handling of a few more cases may be implemented
eventually.

Reviewers: sbenza, djasper

Reviewed By: djasper

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D4478

llvm-svn: 212924

1 files changed, 91 insertions, 8 deletions

diff --git a/clang-tools-extra/test/clang-tidy/avoid-c-style-casts.cpp b/clang-tools-extra/test/clang-tidy/avoid-c-style-casts.cpp
index 8b9feb43d93..a81c26246b0 100644
--- a/clang-tools-extra/test/clang-tidy/avoid-c-style-casts.cpp
+++ b/clang-tools-extra/test/clang-tidy/avoid-c-style-casts.cpp
@@ -1,14 +1,56 @@
-// RUN: clang-tidy -checks=-*,google-readability-casting %s -- | FileCheck %s
-
-// CHECK-NOT: warning:
+// RUN: $(dirname %s)/check_clang_tidy_fix.sh %s google-readability-casting %t
+// REQUIRES: shell
 
 bool g() { return false; }
 
-void f(int a, double b) {
+struct X {};
+struct Y : public X {};
+
+void f(int a, double b, const char *cpc, const void *cpv, X *pX) {
+  const char *cpc2 = (const char*)cpc;
+  // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: Redundant cast to the same type. [google-readability-casting]
+  // CHECK-FIXES: const char *cpc2 = cpc;
+
+  char *pc = (char*)cpc;
+  // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: C-style casts are discouraged. Use const_cast. {{.*}}
+  // CHECK-FIXES: char *pc = const_cast<char *>(cpc);
+
+  char *pc2 = (char*)(cpc + 33);
+  // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: C-style casts are discouraged. Use const_cast. {{.*}}
+  // CHECK-FIXES: char *pc2 = const_cast<char *>((cpc + 33));
+
+  const char &crc = *cpc;
+  char &rc = (char&)crc;
+  // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: C-style casts are discouraged. Use const_cast. {{.*}}
+  // CHECK-FIXES: char &rc = const_cast<char &>(crc);
+
+  char &rc2 = (char&)*cpc;
+  // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: C-style casts are discouraged. Use const_cast. {{.*}}
+  // CHECK-FIXES: char &rc2 = const_cast<char &>(*cpc);
+
+  char ** const* const* ppcpcpc;
+  char ****ppppc = (char****)ppcpcpc;
+  // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: C-style casts are discouraged. Use const_cast. {{.*}}
+  // CHECK-FIXES: char ****ppppc = const_cast<char ****>(ppcpcpc);
+
   int b1 = (int)b;
-  // CHECK: :[[@LINE-1]]:12: warning: C-style casts are discouraged. Use static_cast{{.*}}
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: C-style casts are discouraged. Use static_cast. [google-readability-casting]
+  // CHECK-FIXES: int b1 = static_cast<int>(b);
+
+  Y *pB = (Y*)pX;
+  // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: C-style casts are discouraged. Use static_cast/const_cast/reinterpret_cast. [google-readability-casting]
+  Y &rB = (Y&)*pX;
+  // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: C-style casts are discouraged. Use static_cast/const_cast/reinterpret_cast. [google-readability-casting]
 
-  // CHECK-NOT: warning:
+  const char *pc3 = (const char*)cpv;
+  // CHECK-MESSAGES: :[[@LINE-1]]:21: warning: C-style casts are discouraged. Use reinterpret_cast. [google-readability-casting]
+  // CHECK-FIXES: const char *pc3 = reinterpret_cast<const char *>(cpv);
+
+  char *pc4 = (char*)cpv;
+  // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: C-style casts are discouraged. Use static_cast/const_cast/reinterpret_cast. [google-readability-casting]
+  // CHECK-FIXES: char *pc4 = (char*)cpv;
+
+  // CHECK-MESSAGES-NOT: warning:
   int b2 = int(b);
   int b3 = static_cast<double>(b);
   int b4 = b;
@@ -17,8 +59,49 @@ void f(int a, double b) {
   return (void)g();
 }
 
-// CHECK-NOT: warning:
+template <typename T>
+void template_function(T t, int n) {
+  int i = (int)t;
+  // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: C-style casts are discouraged. Use static_cast/const_cast/reinterpret_cast.
+  // CHECK-FIXES: int i = (int)t;
+  int j = (int)n;
+  // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: Redundant cast to the same type.
+  // CHECK-FIXES: int j = n;
+}
+
+template <typename T>
+struct TemplateStruct {
+  void f(T t, int n) {
+    int k = (int)t;
+    // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: C-style casts are discouraged. Use static_cast/const_cast/reinterpret_cast.
+    // CHECK-FIXES: int k = (int)t;
+    int l = (int)n;
+    // CHECK-MESSAGES: :[[@LINE-1]]:13: warning: Redundant cast to the same type.
+    // CHECK-FIXES: int l = n;
+  }
+};
+
+void test_templates() {
+  template_function(1, 42);
+  template_function(1.0, 42);
+  TemplateStruct<int>().f(1, 42);
+  TemplateStruct<double>().f(1.0, 42);
+}
+
+#define CAST(type, value) (type)(value)
+void macros(double d) {
+  int i = CAST(int, d);
+  // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: C-style casts are discouraged. Use static_cast.
+  // CHECK-FIXES: #define CAST(type, value) (type)(value)
+  // CHECK-FIXES: int i = CAST(int, d);
+}
+
 enum E { E1 = 1 };
 template <E e>
-struct A { static const E ee = e; };
+struct A {
+  // Usage of template argument e = E1 is represented as (E)1 in the AST for
+  // some reason. We have a special treatment of this case to avoid warnings
+  // here.
+  static const E ee = e;
+};
 struct B : public A<E1> {};