[clang] Add AST matcher for block expressions 🔍

Summary:
This change adds a new AST matcher for block expressions.

Test Notes:
Ran the clang unit tests.

Reviewers: aaron.ballman

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D55546

llvm-svn: 349004

5 files changed, 22 insertions, 0 deletions

diff --git a/clang/docs/LibASTMatchersReference.html b/clang/docs/LibASTMatchersReference.html
index 0a8a5a95faf8..28017cab39d5 100644
--- a/clang/docs/LibASTMatchersReference.html
+++ b/clang/docs/LibASTMatchersReference.html
@@ -707,6 +707,14 @@ Example matches a || b
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('blockExpr0')"><a name="blockExpr0Anchor">blockExpr</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1BlockExpr.html">BlockExpr</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="blockExpr0"><pre>MAtches a reference to a block.
+
+Example: matches "^{}":
+  void f() { ^{}(); }
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('breakStmt0')"><a name="breakStmt0Anchor">breakStmt</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1BreakStmt.html">BreakStmt</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="breakStmt0"><pre>Matches break statements.
 
diff --git a/clang/include/clang/ASTMatchers/ASTMatchers.h b/clang/include/clang/ASTMatchers/ASTMatchers.h
index e06bda7d3efb..b913e54b371b 100644
--- a/clang/include/clang/ASTMatchers/ASTMatchers.h
+++ b/clang/include/clang/ASTMatchers/ASTMatchers.h
@@ -1798,6 +1798,14 @@ extern const internal::VariadicDynCastAllOfMatcher<Stmt, DeclRefExpr>
 extern const internal::VariadicDynCastAllOfMatcher<Stmt, ObjCIvarRefExpr>
     objcIvarRefExpr;
 
+/// Matches a reference to a block.
+///
+/// Example: matches "^{}":
+/// \code
+///   void f() { ^{}(); }
+/// \endcode
+extern const internal::VariadicDynCastAllOfMatcher<Stmt, BlockExpr> blockExpr;
+
 /// Matches if statements.
 ///
 /// Example matches 'if (x) {}'
diff --git a/clang/lib/ASTMatchers/ASTMatchersInternal.cpp b/clang/lib/ASTMatchers/ASTMatchersInternal.cpp
index 08fca5b46bdc..6a87a672752d 100644
--- a/clang/lib/ASTMatchers/ASTMatchersInternal.cpp
+++ b/clang/lib/ASTMatchers/ASTMatchersInternal.cpp
@@ -688,6 +688,7 @@ const internal::VariadicDynCastAllOfMatcher<Stmt, CXXOperatorCallExpr>
 const internal::VariadicDynCastAllOfMatcher<Stmt, Expr> expr;
 const internal::VariadicDynCastAllOfMatcher<Stmt, DeclRefExpr> declRefExpr;
 const internal::VariadicDynCastAllOfMatcher<Stmt, ObjCIvarRefExpr> objcIvarRefExpr;
+const internal::VariadicDynCastAllOfMatcher<Stmt, BlockExpr> blockExpr;
 const internal::VariadicDynCastAllOfMatcher<Stmt, IfStmt> ifStmt;
 const internal::VariadicDynCastAllOfMatcher<Stmt, ForStmt> forStmt;
 const internal::VariadicDynCastAllOfMatcher<Stmt, CXXForRangeStmt>
diff --git a/clang/lib/ASTMatchers/Dynamic/Registry.cpp b/clang/lib/ASTMatchers/Dynamic/Registry.cpp
index edebb5c43a58..5f11c153dc45 100644
--- a/clang/lib/ASTMatchers/Dynamic/Registry.cpp
+++ b/clang/lib/ASTMatchers/Dynamic/Registry.cpp
@@ -139,6 +139,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(binaryConditionalOperator);
   REGISTER_MATCHER(binaryOperator);
   REGISTER_MATCHER(blockDecl);
+  REGISTER_MATCHER(blockExpr);
   REGISTER_MATCHER(blockPointerType);
   REGISTER_MATCHER(booleanType);
   REGISTER_MATCHER(breakStmt);
diff --git a/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp b/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
index e37bcbeec1f3..d1f949543221 100644
--- a/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
+++ b/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
@@ -1386,6 +1386,10 @@ TEST(ObjCIvarRefExprMatcher, IvarExpr) {
         hasDeclaration(namedDecl(hasName("y"))))));
 }
 
+TEST(BlockExprMatcher, BlockExpr) {
+  EXPECT_TRUE(matchesObjC("void f() { ^{}(); }", blockExpr()));
+}
+
 TEST(StatementCountIs, FindsNoStatementsInAnEmptyCompoundStatement) {
   EXPECT_TRUE(matches("void f() { }",
                       compoundStmt(statementCountIs(0))));