[clang-format] Improve detection of Objective-C block types

Summary:
Previously, clang-format would detect the following as an
Objective-C block type:

  FOO(^);

when it actually must be a C or C++ macro dealing with an XOR
statement or an XOR operator overload.

According to the Clang Block Language Spec:

https://clang.llvm.org/docs/BlockLanguageSpec.html

block types are of the form:

  int (^)(char, float)

and block variables of block type are of the form:

  void (^blockReturningVoidWithVoidArgument)(void);
  int (^blockReturningIntWithIntAndCharArguments)(int, char);
  void (^arrayOfTenBlocksReturningVoidWithIntArgument[10])(int);

This tightens up the detection so we don't unnecessarily detect
C macros which pass in the XOR operator.

Depends On D43904

Test Plan: New tests added. Ran tests with:
  make -j12 FormatTests &&
  ./tools/clang/unittests/Format/FormatTests

Reviewers: krasimir, jolesiak, djasper

Reviewed By: djasper

Subscribers: djasper, cfe-commits, klimek

Differential Revision: https://reviews.llvm.org/D43906

llvm-svn: 327285

1 files changed, 9 insertions, 0 deletions

diff --git a/clang/unittests/Format/FormatTestObjC.cpp b/clang/unittests/Format/FormatTestObjC.cpp
index 8773088c82e..efc227d3109 100644
--- a/clang/unittests/Format/FormatTestObjC.cpp
+++ b/clang/unittests/Format/FormatTestObjC.cpp
@@ -845,6 +845,15 @@ TEST_F(FormatTestObjC, ObjCAt) {
   verifyFormat("@ /*foo*/ interface");
 }
 
+TEST_F(FormatTestObjC, ObjCBlockTypesAndVariables) {
+  verifyFormat("void DoStuffWithBlockType(int (^)(char));");
+  verifyFormat("int (^foo)(char, float);");
+  verifyFormat("int (^foo[10])(char, float);");
+  verifyFormat("int (^foo[kNumEntries])(char, float);");
+  verifyFormat("int (^foo[kNumEntries + 10])(char, float);");
+  verifyFormat("int (^foo[(kNumEntries + 10)])(char, float);");
+}
+
 TEST_F(FormatTestObjC, ObjCSnippets) {
   verifyFormat("@autoreleasepool {\n"
                "  foo();\n"