[ASTMatchers] Add a new matcher for callee declarations of Obj-C message expressions

[ziqingluo-90]

Summary

For an Obj-C message expression [o m], the adding matcher will match the declaration of the method m. This matcher is the Obj-C counterpart of the existing callee ASTMatcher which matches function/method declarations for C/C++ calls. So I think this matcher is general enough to be added to the ASTMatcher.h.

[njames93]

LGTM

[NoQ]

clang/include/clang/ASTMatchers/ASTMatchers.h

3841

Nitpick carryover: needs capital letter and .

[aaron.ballman]

clang/include/clang/ASTMatchers/ASTMatchers.h

3841

Don't forget to regen the docs when you fix this, too. :-)

3853

Is there a reason why we want a separate matcher here instead of overloading callee()?

[ziqingluo-90]

clang/include/clang/ASTMatchers/ASTMatchers.h

3853

This is a good question!

callee has already been overloaded to accept both Matcher<Decl> and Matcher<Stmt> as the parameter. In my case, I will need callee to be polymorphic in returning both Matcher<CallExpr> and Matcher<ObjCMessageExpr> types. So that will end up in 4 definitions of callee, one of which has different return type and parameter type from one of the others.

Is this achievable? I know I can overload parameters or make return types polymorphic, but can I mix them together?

[ziqingluo-90]

clang/include/clang/ASTMatchers/ASTMatchers.h

3853

I figured it out. I will soon update this patch to simply overload callee

[ziqingluo-90]

Taking @aaron.ballman 's advice to overload callee instead of creating a new matcher. Avoid to bloat ASTMatchers.h.

Sorry to the reviewers that have to review this patch again.

[aaron.ballman]

Thank you, this is looking really promising!

Can you also add a test to unittests/ASTMatchers/Dynamic/RegistryTest.cpp to the TEST_F(RegistryTest, OverloadedMatchers) test which tests the behavior of callee() to make sure it works from dynamic matchers? If that test fails, I think you may need to update lib/ASTMatchers/Dynamic/Registry.cpp to add a REGISTER_OVERLOADED_3 that is used by both callee and equals.

clang/include/clang/ASTMatchers/ASTMatchers.h

3871

This way you get an assert if someone adds another type and forgets to update the rest of the body.

[ziqingluo-90]

Added a test to unittests/ASTMatchers/Dynamic/RegistryTest.cpp and confirms that the overloaded callee still works with dynamic matchers

[aaron.ballman]

LGTM, thank you!

[ziqingluo-90]

Thanks @aaron.ballman , I plan to commit this patch on Monday (18th July 2022).

clang/docs/LibASTMatchersReference.html

Usable as: Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1BlockDecl.html">BlockDecl</a>&gt;, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXBaseSpecifier.html">CXXBaseSpecifier</a>&gt;,
   Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXUnresolvedConstructExpr.html">CXXUnresolvedConstructExpr</a>&gt;,
   Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ClassTemplateSpecializationDecl.html">ClassTemplateSpecializationDecl</a>&gt;, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CompoundLiteralExpr.html">CompoundLiteralExpr</a>&gt;,
   Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1DeclaratorDecl.html">DeclaratorDecl</a>&gt;, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ExplicitCastExpr.html">ExplicitCastExpr</a>&gt;,
   Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCPropertyDecl.html">ObjCPropertyDecl</a>&gt;, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1TemplateArgumentLoc.html">TemplateArgumentLoc</a>&gt;,
   Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1TypedefNameDecl.html">TypedefNameDecl</a>&gt;
 </pre></td></tr>
 
 
-<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CallExpr.html">CallExpr</a>&gt;</td><td class="name" onclick="toggle('callee1')"><a name="callee1Anchor">callee</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt; InnerMatcher</td></tr>
-<tr><td colspan="4" class="doc" id="callee1"><pre>Matches if the call expression's callee's declaration matches the
-given matcher.
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CallExpr.html">CallExpr</a>&gt;</td><td class="name" onclick="toggle('callee2')"><a name="callee2Anchor">callee</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt; InnerMatcher</td></tr>
+<tr><td colspan="4" class="doc" id="callee2"><pre>Matches 1) if the call expression's callee's declaration matches the
+given matcher; or 2) if the Obj-C message expression's callee's method
+declaration matches the given matcher.
 
 Example matches y.x() (matcher = callExpr(callee(
                                    cxxMethodDecl(hasName("x")))))
   class Y { public: void x(); };
   void z() { Y y; y.x(); }
+
+Example 2. Matches [I foo] with
+objcMessageExpr(callee(objcMethodDecl(hasName("foo"))))
+
+  @interface I: NSObject
+  +(void)foo;
+  @end
+  ...
+  [I foo]
 </pre></td></tr>
 
 
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CallExpr.html">CallExpr</a>&gt;</td><td class="name" onclick="toggle('callee0')"><a name="callee0Anchor">callee</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt; InnerMatcher</td></tr>
 <tr><td colspan="4" class="doc" id="callee0"><pre>Matches if the call expression's callee expression matches.
 
 Given
   class Y { void x() { this-&gt;x(); x(); Y y; y.x(); } };

 
 
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCInterfaceDecl.html">ObjCInterfaceDecl</a>&gt;</td><td class="name" onclick="toggle('isSameOrDerivedFrom1')"><a name="isSameOrDerivedFrom1Anchor">isSameOrDerivedFrom</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1NamedDecl.html">NamedDecl</a>&gt; Base</td></tr>
 <tr><td colspan="4" class="doc" id="isSameOrDerivedFrom1"><pre>Similar to isDerivedFrom(), but also matches classes that directly
 match Base.
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;</td><td class="name" onclick="toggle('callee1')"><a name="callee1Anchor">callee</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt; InnerMatcher</td></tr>
+<tr><td colspan="4" class="doc" id="callee1"><pre>Matches 1) if the call expression's callee's declaration matches the
+given matcher; or 2) if the Obj-C message expression's callee's method
+declaration matches the given matcher.
+
+Example matches y.x() (matcher = callExpr(callee(
+                                   cxxMethodDecl(hasName("x")))))
+  class Y { public: void x(); };
+  void z() { Y y; y.x(); }
+
+Example 2. Matches [I foo] with
+objcMessageExpr(callee(objcMethodDecl(hasName("foo"))))
+
+  @interface I: NSObject
+  +(void)foo;
+  @end
+  ...
+  [I foo]
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;</td><td class="name" onclick="toggle('hasAnyArgument3')"><a name="hasAnyArgument3Anchor">hasAnyArgument</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
 <tr><td colspan="4" class="doc" id="hasAnyArgument3"><pre>Matches any argument of a call expression or a constructor call
 expression, or an ObjC-message-send expression.
 
 Given
   void x(int, int, int) { int y; x(1, y, 42); }
 callExpr(hasAnyArgument(declRefExpr()))
   matches x(1, y, 42)

clang/include/clang/ASTMatchers/ASTMatchers.h

 /// implemented in terms of implicit casts.
 AST_MATCHER_P(CallExpr, callee, internal::Matcher<Stmt>,
               InnerMatcher) {
   const Expr *ExprNode = Node.getCallee();
   return (ExprNode != nullptr &&
           InnerMatcher.matches(*ExprNode, Finder, Builder));
 }
 
-/// Matches if the call expression's callee's declaration matches the
-/// given matcher.
+/// Matches 1) if the call expression's callee's declaration matches the
+/// given matcher; or 2) if the Obj-C message expression's callee's method
+/// declaration matches the given matcher.
 ///
 /// Example matches y.x() (matcher = callExpr(callee(
 ///                                    cxxMethodDecl(hasName("x")))))
 /// \code
 ///   class Y { public: void x(); };
 ///   void z() { Y y; y.x(); }
 /// \endcode
-AST_MATCHER_P_OVERLOAD(CallExpr, callee, internal::Matcher<Decl>, InnerMatcher,
-                       1) {
-  return callExpr(hasDeclaration(InnerMatcher)).matches(Node, Finder, Builder);
+///
+/// Example 2. Matches [I foo] with
+/// objcMessageExpr(callee(objcMethodDecl(hasName("foo"))))
+///
+/// \code
+///   @interface I: NSObject
+///   +(void)foo;
+///   @end
+///   ...
+///   [I foo]
+/// \endcode
+AST_POLYMORPHIC_MATCHER_P_OVERLOAD(
+    callee, AST_POLYMORPHIC_SUPPORTED_TYPES(ObjCMessageExpr, CallExpr),
+    internal::Matcher<Decl>, InnerMatcher, 1) {
+  if (const auto *CallNode = dyn_cast<CallExpr>(&Node))
+    return callExpr(hasDeclaration(InnerMatcher))
+        .matches(Node, Finder, Builder);
+  else {
+    // The dynamic cast below is guaranteed to succeed as there are only 2
+    // supported return types.
+    const auto *MsgNode = cast<ObjCMessageExpr>(&Node);
+    const Decl *DeclNode = MsgNode->getMethodDecl();
+    return (DeclNode != nullptr &&
+            InnerMatcher.matches(*DeclNode, Finder, Builder));
+  }
 }
 
 /// Matches if the expression's or declaration's type matches a type
 /// matcher.
 ///
 /// Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X")))))
 ///             and z (matcher = varDecl(hasType(cxxRecordDecl(hasName("X")))))
 ///             and U (matcher = typedefDecl(hasType(asString("int")))

clang/unittests/ASTMatchers/ASTMatchersNodeTest.cpp

if (!GetParam().isCXX14OrLater()) {
     return;
   }
   EXPECT_FALSE(matches(
       "int main() { auto lambda = [xx = 1] {return xx;}; }",
       lambdaExpr(hasAnyCapture(lambdaCapture(capturesVar(varDecl(
           hasName("cc"), hasInitializer(integerLiteral(equals(1))))))))));
 }
 
+TEST(ASTMatchersTestObjC, ObjCMessageCalees) {
+  StatementMatcher MessagingFoo =
+      objcMessageExpr(callee(objcMethodDecl(hasName("foo"))));
+
+  EXPECT_TRUE(matchesObjC("@interface I"
+                          "+ (void)foo;"
+                          "@end\n"
+                          "int main() {"
+                          "  [I foo];"
+                          "}",
+                          MessagingFoo));
+  EXPECT_TRUE(notMatchesObjC("@interface I"
+                             "+ (void)foo;"
+                             "+ (void)bar;"
+                             "@end\n"
+                             "int main() {"
+                             "  [I bar];"
+                             "}",
+                             MessagingFoo));
+  EXPECT_TRUE(matchesObjC("@interface I"
+                          "- (void)foo;"
+                          "- (void)bar;"
+                          "@end\n"
+                          "int main() {"
+                          "  I *i;"
+                          "  [i foo];"
+                          "}",
+                          MessagingFoo));
+  EXPECT_TRUE(notMatchesObjC("@interface I"
+                             "- (void)foo;"
+                             "- (void)bar;"
+                             "@end\n"
+                             "int main() {"
+                             "  I *i;"
+                             "  [i bar];"
+                             "}",
+                             MessagingFoo));
+}
+
 TEST(ASTMatchersTestObjC, ObjCMessageExpr) {
   // Don't find ObjCMessageExpr where none are present.
   EXPECT_TRUE(notMatchesObjC("", objcMessageExpr(anything())));
 
   StringRef Objc1String = "@interface Str "
                           " - (Str *)uppercaseString;"
                           "@end "
                           "@interface foo "

clang/unittests/ASTMatchers/Dynamic/RegistryTest.cpp

TEST_F(RegistryTest, OverloadedMatchers) {
   Matcher<Stmt> CallExpr1 = constructMatcher(
       "callExpr",
       constructMatcher(
           "callee",
           constructMatcher("cxxMethodDecl",
                            constructMatcher("hasName", StringRef("x")))))
       .getTypedMatcher<Stmt>();
 
+  Matcher<Stmt> ObjCMsgExpr =
+      constructMatcher(
+          "objcMessageExpr",
+          constructMatcher(
+              "callee",
+              constructMatcher("objcMethodDecl",
+                               constructMatcher("hasName", StringRef("x")))))
+          .getTypedMatcher<Stmt>();
+
   std::string Code = "class Y { public: void x(); }; void z() { Y y; y.x(); }";
   EXPECT_FALSE(matches(Code, CallExpr0));
   EXPECT_TRUE(matches(Code, CallExpr1));
+  EXPECT_FALSE(matches(Code, ObjCMsgExpr));
 
   Code = "class Z { public: void z() { this->z(); } };";
   EXPECT_TRUE(matches(Code, CallExpr0));
   EXPECT_FALSE(matches(Code, CallExpr1));
+  EXPECT_FALSE(matches(Code, ObjCMsgExpr));
+
+  Code = "@interface I "
+         "+ (void)x; "
+         "@end\n"
+         "int main() { [I x]; }";
+  EXPECT_FALSE(matchesObjC(Code, CallExpr0));
+  EXPECT_FALSE(matchesObjC(Code, CallExpr1));
+  EXPECT_TRUE(matchesObjC(Code, ObjCMsgExpr));
 
   Matcher<Decl> DeclDecl = declaratorDecl(hasTypeLoc(
       constructMatcher(
           "loc", constructMatcher("asString", StringRef("const double *")))
           .getTypedMatcher<TypeLoc>()));
 
   Matcher<NestedNameSpecifierLoc> NNSL =
       constructMatcher(