[ASTMatchers] Add an isMain() matcher

Differential Revision: https://reviews.llvm.org/D49615

llvm-svn: 337761

Author: George Karpenkov

clang/docs/LibASTMatchersReference.html

@@ -2919,6 +2919,12 @@ <h2 id="narrowing-matchers">Narrowing Matchers</h2>
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html">FunctionDecl</a>&gt;</td><td class="name" onclick="toggle('isMain0')"><a name="isMain0Anchor">isMain</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isMain0"><pre>Determines whether the function is "main", which is the entry point
+into an executable program.
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html">FunctionDecl</a>&gt;</td><td class="name" onclick="toggle('isNoReturn0')"><a name="isNoReturn0Anchor">isNoReturn</a></td><td></td></tr>
 <tr><td colspan="4" class="doc" id="isNoReturn0"><pre>Matches FunctionDecls that have a noreturn attribute.
 

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -616,6 +616,12 @@ AST_MATCHER_P(FieldDecl, hasInClassInitializer, internal::Matcher<Expr>,
           InnerMatcher.matches(*Initializer, Finder, Builder));
 }
 
+/// Determines whether the function is "main", which is the entry point
+/// into an executable program.
+AST_MATCHER(FunctionDecl, isMain) {
+  return Node.isMain();
+}
+
 /// Matches the specialized template of a specialization declaration.
 ///
 /// Given

clang/lib/ASTMatchers/Dynamic/Registry.cpp

@@ -359,6 +359,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(isInTemplateInstantiation);
   REGISTER_MATCHER(isLambda);
   REGISTER_MATCHER(isListInitialization);
+  REGISTER_MATCHER(isMain);
   REGISTER_MATCHER(isMemberInitializer);
   REGISTER_MATCHER(isMoveAssignmentOperator);
   REGISTER_MATCHER(isMoveConstructor);

clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp

@@ -2158,5 +2158,13 @@ TEST(IsAssignmentOperator, Basic) {
       notMatches("void x() { int a; if(a == 0) return; }", BinAsgmtOperator));
 }
 
+TEST(Matcher, isMain) {
+  EXPECT_TRUE(
+    matches("int main() {}", functionDecl(isMain())));
+
+  EXPECT_TRUE(
+    notMatches("int main2() {}", functionDecl(isMain())));
+}
+
 } // namespace ast_matchers
 } // namespace clang