From: Alexander Kornienko <alexfh@google.com>
Date: Thu, 29 Jan 2015 15:17:13 +0000 (+0000)
Subject: [clang-tidy] Fix some false positives in google-readability-casting
X-Git-Tag: llvmorg-3.7.0-rc1~13736
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=78070fbae59b29b5fc7b970b948a9991cc9e9bbc;p=platform%2Fupstream%2Fllvm.git

[clang-tidy] Fix some false positives in google-readability-casting

Summary:
Ignore C-style casts in extern "C" {} sections. Be more careful when
detecting redundant casts between typedefs to the same type - emit a more
specific warning and don't automatically fix them.

Reviewers: klimek

Reviewed By: klimek

Subscribers: curdeius, cfe-commits

Differential Revision: http://reviews.llvm.org/D7247

llvm-svn: 227444
---

diff --git a/clang-tools-extra/clang-tidy/google/AvoidCStyleCastsCheck.cpp b/clang-tools-extra/clang-tidy/google/AvoidCStyleCastsCheck.cpp
index 093250d..20440fe 100644
--- a/clang-tools-extra/clang-tidy/google/AvoidCStyleCastsCheck.cpp
+++ b/clang-tools-extra/clang-tidy/google/AvoidCStyleCastsCheck.cpp
@@ -68,19 +68,30 @@ void AvoidCStyleCastsCheck::check(const MatchFinder::MatchResult &Result) {
   if (CastExpr->getTypeAsWritten()->isVoidType())
     return;
 
-  QualType SourceType =
-      CastExpr->getSubExprAsWritten()->getType().getCanonicalType();
-  QualType DestType = CastExpr->getTypeAsWritten().getCanonicalType();
+  QualType SourceType = CastExpr->getSubExprAsWritten()->getType();
+  QualType DestType = CastExpr->getTypeAsWritten();
 
   if (SourceType == DestType) {
-    diag(CastExpr->getLocStart(), "Redundant cast to the same type.")
+    diag(CastExpr->getLocStart(), "redundant cast to the same type")
         << FixItHint::CreateRemoval(ParenRange);
     return;
   }
+  SourceType = SourceType.getCanonicalType();
+  DestType = DestType.getCanonicalType();
+  if (SourceType == DestType) {
+    diag(CastExpr->getLocStart(),
+         "possibly redundant cast between typedefs of the same type");
+    return;
+  }
+
 
   // The rest of this check is only relevant to C++.
   if (!Result.Context->getLangOpts().CPlusPlus)
     return;
+  // Ignore code inside extern "C" {} blocks.
+  if (!match(expr(hasAncestor(linkageSpecDecl())), *CastExpr, *Result.Context)
+           .empty())
+    return;
 
   // Leave type spelling exactly as it was (unlike
   // getTypeAsWritten().getAsString() which would spell enum types 'enum X').
@@ -94,7 +105,7 @@ void AvoidCStyleCastsCheck::check(const MatchFinder::MatchResult &Result) {
       diag(CastExpr->getLocStart(), "C-style casts are discouraged. %0");
 
   auto ReplaceWithCast = [&](StringRef CastType) {
-    diag_builder << ("Use " + CastType + ".").str();
+    diag_builder << ("Use " + CastType).str();
 
     const Expr *SubExpr = CastExpr->getSubExprAsWritten()->IgnoreImpCasts();
     std::string CastText = (CastType + "<" + DestTypeString + ">").str();
@@ -108,6 +119,7 @@ void AvoidCStyleCastsCheck::check(const MatchFinder::MatchResult &Result) {
     }
     diag_builder << FixItHint::CreateReplacement(ParenRange, CastText);
   };
+
   // Suggest appropriate C++ cast. See [expr.cast] for cast notation semantics.
   switch (CastExpr->getCastKind()) {
   case CK_NoOp:
@@ -145,7 +157,7 @@ void AvoidCStyleCastsCheck::check(const MatchFinder::MatchResult &Result) {
     break;
   }
 
-  diag_builder << "Use static_cast/const_cast/reinterpret_cast.";
+  diag_builder << "Use static_cast/const_cast/reinterpret_cast";
 }
 
 } // namespace readability
diff --git a/clang-tools-extra/test/clang-tidy/google-readability-casting.c b/clang-tools-extra/test/clang-tidy/google-readability-casting.c
index 55ee095..9765365 100644
--- a/clang-tools-extra/test/clang-tidy/google-readability-casting.c
+++ b/clang-tools-extra/test/clang-tidy/google-readability-casting.c
@@ -3,7 +3,7 @@
 
 void f(const char *cpc) {
   const char *cpc2 = (const char*)cpc;
-  // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: Redundant cast to the same type. [google-readability-casting]
+  // 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;
 }
diff --git a/clang-tools-extra/test/clang-tidy/google-readability-casting.cpp b/clang-tools-extra/test/clang-tidy/google-readability-casting.cpp
index 97df300..a8c1989 100644
--- a/clang-tools-extra/test/clang-tidy/google-readability-casting.cpp
+++ b/clang-tools-extra/test/clang-tidy/google-readability-casting.cpp
@@ -9,67 +9,83 @@ 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-MESSAGES: :[[@LINE-1]]:22: warning: redundant cast to the same type [google-readability-casting]
   // CHECK-FIXES: const char *cpc2 = cpc;
 
+  typedef const char *Typedef1;
+  typedef const char *Typedef2;
+  Typedef1 t1;
+  (Typedef2)t1;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: possibly redundant cast between typedefs of the same type [google-readability-casting]
+  // CHECK-FIXES: {{^}}  (Typedef2)t1;
+  (const char*)t1;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: possibly redundant cast {{.*}}
+  // CHECK-FIXES: {{^}}  (const char*)t1;
+  (Typedef1)cpc;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: possibly redundant cast {{.*}}
+  // CHECK-FIXES: {{^}}  (Typedef1)cpc;
+  (Typedef1)t1;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: redundant cast to the same type
+  // CHECK-FIXES: {{^}}  t1;
+
   char *pc = (char*)cpc;
-  // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: C-style casts are discouraged. Use const_cast. {{.*}}
+  // CHECK-MESSAGES: :[[@LINE-1]]:14: warning: C-style casts are discouraged. Use const_cast [google-readability-casting]
   // 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-MESSAGES: :[[@LINE-1]]:15: warning: {{.*}}. 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-MESSAGES: :[[@LINE-1]]:14: warning: {{.*}}. 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-MESSAGES: :[[@LINE-1]]:15: warning: {{.*}}. 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-MESSAGES: :[[@LINE-1]]:20: warning: {{.*}}. Use const_cast {{.*}}
   // CHECK-FIXES: char ****ppppc = const_cast<char****>(ppcpcpc);
 
   char ***pppc = (char***)*(ppcpcpc);
-  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: C-style casts are discouraged. Use const_cast. {{.*}}
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: {{.*}}. Use const_cast {{.*}}
   // CHECK-FIXES: char ***pppc = const_cast<char***>(*(ppcpcpc));
 
   char ***pppc2 = (char***)(*ppcpcpc);
-  // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: C-style casts are discouraged. Use const_cast. {{.*}}
+  // CHECK-MESSAGES: :[[@LINE-1]]:19: warning: {{.*}}. Use const_cast {{.*}}
   // CHECK-FIXES: char ***pppc2 = const_cast<char***>(*ppcpcpc);
 
   char *pc5 = (char*)(const char*)(cpv);
-  // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: C-style casts are discouraged. Use const_cast. {{.*}}
-  // CHECK-MESSAGES: :[[@LINE-2]]:22: warning: C-style casts are discouraged. Use reinterpret_cast. {{.*}}
+  // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: {{.*}}. Use const_cast {{.*}}
+  // CHECK-MESSAGES: :[[@LINE-2]]:22: warning: {{.*}}. Use reinterpret_cast {{.*}}
   // CHECK-FIXES: char *pc5 = const_cast<char*>(reinterpret_cast<const char*>(cpv));
 
   int b1 = (int)b;
-  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: C-style casts are discouraged. Use static_cast. [google-readability-casting]
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: {{.*}}. Use static_cast {{.*}}
   // 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]
+  // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: {{.*}}. Use static_cast/const_cast/reinterpret_cast {{.*}}
   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-MESSAGES: :[[@LINE-1]]:11: warning: {{.*}}. Use static_cast/const_cast/reinterpret_cast {{.*}}
 
   const char *pc3 = (const char*)cpv;
-  // CHECK-MESSAGES: :[[@LINE-1]]:21: warning: C-style casts are discouraged. Use reinterpret_cast. [google-readability-casting]
+  // CHECK-MESSAGES: :[[@LINE-1]]:21: warning: {{.*}}. Use reinterpret_cast {{.*}}
   // 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-MESSAGES: :[[@LINE-1]]:15: warning: {{.*}}. Use static_cast/const_cast/reinterpret_cast {{.*}}
   // CHECK-FIXES: char *pc4 = (char*)cpv;
 
   b1 = (int)Enum1;
-  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: C-style casts are discouraged. Use static_cast. [google-readability-casting]
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: {{.*}}. Use static_cast {{.*}}
   // CHECK-FIXES: b1 = static_cast<int>(Enum1);
 
   Enum e = (Enum)b1;
-  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: C-style casts are discouraged. Use static_cast. [google-readability-casting]
+  // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: {{.*}}. Use static_cast {{.*}}
   // CHECK-FIXES: Enum e = static_cast<Enum>(b1);
 
   // CHECK-MESSAGES-NOT: warning:
@@ -84,10 +100,10 @@ void f(int a, double b, const char *cpc, const void *cpv, X *pX) {
 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-MESSAGES: :[[@LINE-1]]:11: warning: {{.*}}. 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-MESSAGES: :[[@LINE-1]]:11: warning: redundant cast to the same type
   // CHECK-FIXES: int j = n;
 }
 
@@ -95,10 +111,10 @@ 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-MESSAGES: :[[@LINE-1]]:13: warning: {{.*}}. 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-MESSAGES: :[[@LINE-1]]:13: warning: redundant cast to the same type
     // CHECK-FIXES: int l = n;
   }
 };
@@ -110,6 +126,15 @@ void test_templates() {
   TemplateStruct<double>().f(1.0, 42);
 }
 
+extern "C" {
+void extern_c_code(const char *cpc) {
+  const char *cpc2 = (const char*)cpc;
+  // CHECK-MESSAGES: :[[@LINE-1]]:22: warning: redundant cast to the same type
+  // CHECK-FIXES: const char *cpc2 = cpc;
+  char *pc = (char*)cpc;
+}
+}
+
 #define CAST(type, value) (type)(value)
 void macros(double d) {
   int i = CAST(int, d);