Add forEachArgumentWithParam AST matcher.

The new matcher allows users to provide a matcher for both the argument
of a CallExpr/CxxConstructExpr a well as the ParmVarDecl of the
argument.

Patch by Felix Berger.

Differential Revision: http://reviews.llvm.org/D13845

llvm-svn: 258042

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -2871,6 +2871,57 @@ AST_MATCHER_P2(FunctionDecl, hasParameter,
               *Node.getParamDecl(N), Finder, Builder));
 }
 
+/// \brief Matches all arguments and their respective ParmVarDecl.
+///
+/// Given
+/// \code
+///   void f(int i);
+///   int y;
+///   f(y);
+/// \endcode
+/// callExpr(declRefExpr(to(varDecl(hasName("y")))),
+/// parmVarDecl(hasType(isInteger())))
+///   matches f(y);
+/// with declRefExpr(...)
+///   matching int y
+/// and parmVarDecl(...)
+///   matching int i
+AST_POLYMORPHIC_MATCHER_P2(forEachArgumentWithParam,
+                           AST_POLYMORPHIC_SUPPORTED_TYPES(CallExpr,
+                                                           CXXConstructExpr),
+                           internal::Matcher<Expr>, ArgMatcher,
+                           internal::Matcher<ParmVarDecl>, ParamMatcher) {
+  BoundNodesTreeBuilder Result;
+  // The first argument of an overloaded member operator is the implicit object
+  // argument of the method which should not be matched against a parameter, so
+  // we skip over it here.
+  BoundNodesTreeBuilder Matches;
+  unsigned ArgIndex = cxxOperatorCallExpr(callee(cxxMethodDecl()))
+                              .matches(Node, Finder, &Matches)
+                          ? 1
+                          : 0;
+  int ParamIndex = 0;
+  bool Matched = false;
+  for (; ArgIndex < Node.getNumArgs(); ++ArgIndex) {
+    BoundNodesTreeBuilder ArgMatches(*Builder);
+    if (ArgMatcher.matches(*(Node.getArg(ArgIndex)->IgnoreParenCasts()),
+                           Finder, &ArgMatches)) {
+      BoundNodesTreeBuilder ParamMatches(ArgMatches);
+      if (expr(anyOf(cxxConstructExpr(hasDeclaration(cxxConstructorDecl(
+                         hasParameter(ParamIndex, ParamMatcher)))),
+                     callExpr(callee(functionDecl(
+                         hasParameter(ParamIndex, ParamMatcher))))))
+              .matches(Node, Finder, &ParamMatches)) {
+        Result.addMatch(ParamMatches);
+        Matched = true;
+      }
+    }
+    ++ParamIndex;
+  }
+  *Builder = std::move(Result);
+  return Matched;
+}
+
 /// \brief Matches any parameter of a function declaration.
 ///
 /// Does not match the 'this' parameter of a method.

clang/lib/ASTMatchers/Dynamic/Registry.cpp

@@ -174,6 +174,7 @@ RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(fieldDecl);
   REGISTER_MATCHER(floatLiteral);
   REGISTER_MATCHER(forEach);
+  REGISTER_MATCHER(forEachArgumentWithParam);
   REGISTER_MATCHER(forEachConstructorInitializer);
   REGISTER_MATCHER(forEachDescendant);
   REGISTER_MATCHER(forEachSwitchCase);

clang/unittests/ASTMatchers/ASTMatchersTest.cpp

@@ -1608,6 +1608,91 @@ TEST(Matcher, AnyArgument) {
   EXPECT_TRUE(notMatches("void x(int, int) { x(1, 2); }", CallArgumentY));
 }
 
+TEST(ForEachArgumentWithParam, ReportsNoFalsePositives) {
+  StatementMatcher ArgumentY =
+      declRefExpr(to(varDecl(hasName("y")))).bind("arg");
+  DeclarationMatcher IntParam = parmVarDecl(hasType(isInteger())).bind("param");
+  StatementMatcher CallExpr =
+      callExpr(forEachArgumentWithParam(ArgumentY, IntParam));
+
+  // IntParam does not match.
+  EXPECT_FALSE(matches("void f(int* i) { int* y; f(y); }", CallExpr));
+  // ArgumentY does not match.
+  EXPECT_FALSE(matches("void f(int i) { int x; f(x); }", CallExpr));
+}
+
+TEST(ForEachArgumentWithParam, MatchesCXXMemberCallExpr) {
+  StatementMatcher ArgumentY =
+      declRefExpr(to(varDecl(hasName("y")))).bind("arg");
+  DeclarationMatcher IntParam = parmVarDecl(hasType(isInteger())).bind("param");
+  StatementMatcher CallExpr =
+      callExpr(forEachArgumentWithParam(ArgumentY, IntParam));
+  EXPECT_TRUE(matchAndVerifyResultTrue(
+      "struct S {"
+      "  const S& operator[](int i) { return *this; }"
+      "};"
+      "void f(S S1) {"
+      "  int y = 1;"
+      "  S1[y];"
+      "}",
+      CallExpr, new VerifyIdIsBoundTo<ParmVarDecl>("param", 1)));
+}
+
+TEST(ForEachArgumentWithParam, MatchesCallExpr) {
+  StatementMatcher ArgumentY =
+      declRefExpr(to(varDecl(hasName("y")))).bind("arg");
+  DeclarationMatcher IntParam = parmVarDecl(hasType(isInteger())).bind("param");
+  StatementMatcher CallExpr =
+      callExpr(forEachArgumentWithParam(ArgumentY, IntParam));
+
+  EXPECT_TRUE(
+      matchAndVerifyResultTrue("void f(int i) { int y; f(y); }", CallExpr,
+                               new VerifyIdIsBoundTo<ParmVarDecl>("param")));
+  EXPECT_TRUE(
+      matchAndVerifyResultTrue("void f(int i) { int y; f(y); }", CallExpr,
+                               new VerifyIdIsBoundTo<DeclRefExpr>("arg")));
+
+  EXPECT_TRUE(matchAndVerifyResultTrue(
+      "void f(int i, int j) { int y; f(y, y); }", CallExpr,
+      new VerifyIdIsBoundTo<ParmVarDecl>("param", 2)));
+  EXPECT_TRUE(matchAndVerifyResultTrue(
+      "void f(int i, int j) { int y; f(y, y); }", CallExpr,
+      new VerifyIdIsBoundTo<DeclRefExpr>("arg", 2)));
+}
+
+TEST(ForEachArgumentWithParam, MatchesConstructExpr) {
+  StatementMatcher ArgumentY =
+      declRefExpr(to(varDecl(hasName("y")))).bind("arg");
+  DeclarationMatcher IntParam = parmVarDecl(hasType(isInteger())).bind("param");
+  StatementMatcher ConstructExpr =
+      cxxConstructExpr(forEachArgumentWithParam(ArgumentY, IntParam));
+
+  EXPECT_TRUE(matchAndVerifyResultTrue(
+      "struct C {"
+      "  C(int i) {}"
+      "};"
+      "int y = 0;"
+      "C Obj(y);",
+      ConstructExpr, new VerifyIdIsBoundTo<ParmVarDecl>("param")));
+}
+
+TEST(ForEachArgumentWithParam, HandlesBoundNodesForNonMatches) {
+  EXPECT_TRUE(matchAndVerifyResultTrue(
+      "void g(int i, int j) {"
+      "  int a;"
+      "  int b;"
+      "  int c;"
+      "  g(a, 0);"
+      "  g(a, b);"
+      "  g(0, b);"
+      "}",
+      functionDecl(
+          forEachDescendant(varDecl().bind("v")),
+          forEachDescendant(callExpr(forEachArgumentWithParam(
+              declRefExpr(to(decl(equalsBoundNode("v")))), parmVarDecl())))),
+      new VerifyIdIsBoundTo<VarDecl>("v", 4)));
+}
+
 TEST(Matcher, ArgumentCount) {
   StatementMatcher Call1Arg = callExpr(argumentCountIs(1));