[clang-tidy] Add a generic header guard checker + LLVM implementation.

The implementation is split into a generic part and a LLVM-specific part.
Other codebases can implement it with their own style. The specific features
supported are:

- Verification (and fixing) of header guards against a style based on the file path
- Automatic insertion of header guards for headers that are missing them
- A warning when the header guard doesn't enable our fancy header guard optimization
(e.g. when there's an include preceeding the guard)
- Automatic insertion of a comment with the guard name after #endif.

For the LLVM style we disable #endif comments for now, they're not very common
in the codebase. We also only flag headers in the include directories, there
doesn't seem to be a common style outside.

Differential Revision: http://reviews.llvm.org/D4867

llvm-svn: 215548

1 files changed, 41 insertions, 0 deletions

diff --git a/clang-tools-extra/unittests/clang-tidy/LLVMModuleTest.cpp b/clang-tools-extra/unittests/clang-tidy/LLVMModuleTest.cpp
index 6bc52b2..b57630d 100644
--- a/clang-tools-extra/unittests/clang-tidy/LLVMModuleTest.cpp
+++ b/clang-tools-extra/unittests/clang-tidy/LLVMModuleTest.cpp
@@ -1,4 +1,5 @@
 #include "ClangTidyTest.h"
+#include "llvm/HeaderGuardCheck.h"
 #include "llvm/IncludeOrderCheck.h"
 #include "llvm/NamespaceCommentCheck.h"
 #include "gtest/gtest.h"
@@ -85,6 +86,46 @@ TEST(NamespaceCommentCheckTest, FixWrongComments) {
                                                   "} // namespace asdf"));
 }
 
+static std::string runHeaderGuardCheck(StringRef Code, const Twine &Filename) {
+  return test::runCheckOnCode<LLVMHeaderGuardCheck>(
+      Code, /*Errors=*/nullptr, Filename, std::string("-xc++-header"));
+}
+
+TEST(LLVMHeaderGuardCheckTest, FixHeaderGuards) {
+  EXPECT_EQ("#ifndef LLVM_ADT_FOO_H\n#define LLVM_ADT_FOO_H\n#endif\n",
+            runHeaderGuardCheck("#ifndef FOO\n#define FOO\n#endif\n",
+                                "include/llvm/ADT/foo.h"));
+
+  // Allow trailing underscores.
+  EXPECT_EQ("#ifndef LLVM_ADT_FOO_H_\n#define LLVM_ADT_FOO_H_\n#endif\n",
+            runHeaderGuardCheck(
+                "#ifndef LLVM_ADT_FOO_H_\n#define LLVM_ADT_FOO_H_\n#endif\n",
+                "include/llvm/ADT/foo.h"));
+
+  EXPECT_EQ("#ifndef LLVM_CLANG_C_BAR_H\n#define LLVM_CLANG_C_BAR_H\n\n\n#endif\n",
+            runHeaderGuardCheck("", "./include/clang-c/bar.h"));
+
+  EXPECT_EQ("#ifndef LLVM_CLANG_LIB_CODEGEN_C_H\n#define "
+            "LLVM_CLANG_LIB_CODEGEN_C_H\n\n\n#endif\n",
+            runHeaderGuardCheck("", "tools/clang/lib/CodeGen/c.h"));
+
+  EXPECT_EQ("#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_X_H\n#define "
+            "LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_X_H\n\n\n#endif\n",
+            runHeaderGuardCheck("", "tools/clang/tools/extra/clang-tidy/x.h"));
+
+  EXPECT_EQ(
+      "int foo;\n#ifndef LLVM_CLANG_BAR_H\n#define LLVM_CLANG_BAR_H\n#endif\n",
+      runHeaderGuardCheck("int foo;\n#ifndef LLVM_CLANG_BAR_H\n"
+                          "#define LLVM_CLANG_BAR_H\n#endif\n",
+                          "include/clang/bar.h"));
+
+  EXPECT_EQ("#ifndef LLVM_CLANG_BAR_H\n#define LLVM_CLANG_BAR_H\n\n"
+            "int foo;\n#ifndef FOOLOLO\n#define FOOLOLO\n#endif\n\n#endif\n",
+            runHeaderGuardCheck(
+                "int foo;\n#ifndef FOOLOLO\n#define FOOLOLO\n#endif\n",
+                "include/clang/bar.h"));
+}
+
 } // namespace test
 } // namespace tidy
 } // namespace clang