ASTMatchers: enable hasBody() matcher for FunctionDecls

[a.sidorin]

Summary

This patch enables matching for FunctionDecls that have bodies.

[a.sidorin]

Update comments and documentation.

[aaron.ballman]

The examples and test code you use seem to imply that the isDefinition() matcher may be all you need; is isDefinition() insufficient for some reason? If so, can you expand the test cases to cover that particular usage? Also, FunctionDecl::getBody() does more work than FunctionDecl::hasBody() -- it would be better to implement the AST matcher in terms of FunctionDecl::hasBody() instead.

[a.sidorin]

Match only FunctionDecls which are definitions and ignore redeclarations without bodies.

[aaron.ballman]

include/clang/ASTMatchers/ASTMatchers.h

3118

s/declaration/definition.

include/clang/ASTMatchers/ASTMatchersInternal.h

1590

Indentation here is incorrect, you should run clang-format over the patch.

lib/ASTMatchers/ASTMatchersInternal.cpp

342 ↗

(On Diff #45232)

The specialization should live in the header file, not the source file.

344 ↗

(On Diff #45232)

I would use Node.doesThisDeclarationHaveABody() instead; otherwise this will match definitions that are explicitly deleted, which isn't particularly useful.

[a.sidorin]

Fix issues pointed on review.

[aaron.ballman]

With one small nit, LGTM, thanks!

include/clang/ASTMatchers/ASTMatchersInternal.h

1596

s/NULL/nullptr

[a.sidorin]

Replace NULL with nullptr.

[aaron.ballman]

Thanks! I went ahead and commit in r258322.

docs/LibASTMatchersReference.html

 
 
 <tr><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1CXXForRangeStmt.html">CXXForRangeStmt</a>&gt;</td><td class="name" onclick="toggle('hasBody3')"><a name="hasBody3Anchor">hasBody</a></td><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt; InnerMatcher</td></tr>
-<tr><td colspan="4" class="doc" id="hasBody3"><pre>Matches a 'for', 'while', or 'do while' statement that has
-a given body.
+<tr><td colspan="4" class="doc" id="hasBody3"><pre>Matches a 'for', 'while', 'do while' statement or a function
+definition that has a given body.
 
 Given
   for (;;) {}

 
 
 <tr><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1DoStmt.html">DoStmt</a>&gt;</td><td class="name" onclick="toggle('hasBody0')"><a name="hasBody0Anchor">hasBody</a></td><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt; InnerMatcher</td></tr>
-<tr><td colspan="4" class="doc" id="hasBody0"><pre>Matches a 'for', 'while', or 'do while' statement that has
-a given body.
+<tr><td colspan="4" class="doc" id="hasBody0"><pre>Matches a 'for', 'while', 'do while' statement or a function
+definition that has a given body.
 
 Given
   for (;;) {}

 
 
 <tr><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1ForStmt.html">ForStmt</a>&gt;</td><td class="name" onclick="toggle('hasBody1')"><a name="hasBody1Anchor">hasBody</a></td><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt; InnerMatcher</td></tr>
-<tr><td colspan="4" class="doc" id="hasBody1"><pre>Matches a 'for', 'while', or 'do while' statement that has
-a given body.
+<tr><td colspan="4" class="doc" id="hasBody1"><pre>Matches a 'for', 'while', 'do while' statement or a function
+definition that has a given body.
 
 Given
   for (;;) {}

 </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('hasBody4')"><a name="hasBody4Anchor">hasBody</a></td><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt; InnerMatcher</td></tr>
+<tr><td colspan="4" class="doc" id="hasBody4"><pre>Matches a 'for', 'while', 'do while' statement or a function
+definition that has a given body.
+
+Given
+  for (;;) {}
+hasBody(compoundStmt())
+  matches 'for (;;) {}'
+with compoundStmt()
+  matching '{}'
+</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('hasParameter0')"><a name="hasParameter0Anchor">hasParameter</a></td><td>unsigned N, Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1ParmVarDecl.html">ParmVarDecl</a>&gt; InnerMatcher</td></tr>
 <tr><td colspan="4" class="doc" id="hasParameter0"><pre>Matches the n'th parameter of a function declaration.
 

 
 
 <tr><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1WhileStmt.html">WhileStmt</a>&gt;</td><td class="name" onclick="toggle('hasBody2')"><a name="hasBody2Anchor">hasBody</a></td><td>Matcher&lt<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt; InnerMatcher</td></tr>
-<tr><td colspan="4" class="doc" id="hasBody2"><pre>Matches a 'for', 'while', or 'do while' statement that has
-a given body.
+<tr><td colspan="4" class="doc" id="hasBody2"><pre>Matches a 'for', 'while', 'do while' statement or a function
+definition that has a given body.
 
 Given
   for (;;) {}

include/clang/ASTMatchers/ASTMatchers.h

   return false;
 }
 
-/// \brief Matches a 'for', 'while', or 'do while' statement that has
-/// a given body.
+/// \brief Matches a 'for', 'while', 'do while' statement or a function
+/// definition that has a given body.
 ///
 /// Given
 /// \code

 AST_POLYMORPHIC_MATCHER_P(hasBody,
                           AST_POLYMORPHIC_SUPPORTED_TYPES(DoStmt, ForStmt,
                                                           WhileStmt,
-                                                          CXXForRangeStmt),
+                                                          CXXForRangeStmt,
+                                                          FunctionDecl),
                           internal::Matcher<Stmt>, InnerMatcher) {
-  const Stmt *const Statement = Node.getBody();
+  const Stmt *const Statement = internal::GetBodyMatcher<NodeType>::get(Node);
   return (Statement != nullptr &&
           InnerMatcher.matches(*Statement, Finder, Builder));
 }

include/clang/ASTMatchers/ASTMatchersInternal.h

   ast_type_traits::DynTypedNode Node;
 };
 
+template <typename Ty>
+struct GetBodyMatcher {
+  static const Stmt *get(const Ty &Node) {
+    return Node.getBody();
+  }
+};
+
+template <>
+inline const Stmt *GetBodyMatcher<FunctionDecl>::get(const FunctionDecl &Node) {
+  return Node.doesThisDeclarationHaveABody() ? Node.getBody() : nullptr;
+}
+
 } // end namespace internal
 } // end namespace ast_matchers
 } // end namespace clang

unittests/ASTMatchers/ASTMatchersTest.cpp

               doStmt(hasBody(compoundStmt()))));
   EXPECT_TRUE(matches("void f() { int p[2]; for (auto x : p) {} }",
               cxxForRangeStmt(hasBody(compoundStmt()))));
+  EXPECT_TRUE(matches("void f() {}", functionDecl(hasBody(compoundStmt()))));
+  EXPECT_TRUE(notMatches("void f();", functionDecl(hasBody(compoundStmt()))));
+  EXPECT_TRUE(matches("void f(); void f() {}",
+                         functionDecl(hasBody(compoundStmt()))));
 }
 
 TEST(HasAnySubstatement, MatchesForTopLevelCompoundStatement) {

unittests/ASTMatchers/Dynamic/ParserTest.cpp

             "1:1: Matcher does not support binding.",
             ParseWithError("isArrow().bind(\"foo\")"));
   EXPECT_EQ("Input value has unresolved overloaded type: "
-            "Matcher<DoStmt|ForStmt|WhileStmt|CXXForRangeStmt>",
+            "Matcher<DoStmt|ForStmt|WhileStmt|CXXForRangeStmt|FunctionDecl>",
             ParseMatcherWithError("hasBody(stmt())"));
 }