[PATCH] D80603: add isAtPosition narrowing matcher for parmVarDecl

[Vy Nguyen via Phabricator via cfe-commits]

oontvoo updated this revision to Diff 266714.
oontvoo added a comment.

use helper for examining the node instead of nested matchers


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D80603/new/

https://reviews.llvm.org/D80603

Files:
  clang/docs/LibASTMatchersReference.html
  clang/include/clang/AST/ASTContext.h
  clang/include/clang/ASTMatchers/ASTMatchers.h
  clang/lib/AST/ASTContext.cpp
  clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp


Index: clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
===================================================================
--- clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
+++ clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
@@ -2643,6 +2643,29 @@
                       parmVarDecl(hasDefaultArgument())));
 }
 
+TEST(IsAtPosition, Basic) {
+  EXPECT_TRUE(matches("void x(int a) {}", parmVarDecl(isAtPosition(0))));
+  EXPECT_TRUE(matches("void x(int a, int b) {}", parmVarDecl(isAtPosition(0))));
+  EXPECT_TRUE(matches("void x(int a, int b) {}", parmVarDecl(isAtPosition(1))));
+  EXPECT_TRUE(notMatches("void x(int val) {}", parmVarDecl(isAtPosition(1))));
+
+  // Tests with function-decls
+  EXPECT_TRUE(matches("void x(int a);", parmVarDecl(isAtPosition(0))));
+  EXPECT_TRUE(matches("void x(int a, int b);", parmVarDecl(isAtPosition(0))));
+  EXPECT_TRUE(matches("void x(int a, int b);", parmVarDecl(isAtPosition(1))));
+  EXPECT_TRUE(notMatches("void x(int val);", parmVarDecl(isAtPosition(1))));
+
+  // Tests with lamdas
+  EXPECT_TRUE(
+      matches("void x() { [](int a) {};  }", parmVarDecl(isAtPosition(0))));
+  EXPECT_TRUE(matches("void x() { [](int a, int b) {}; }",
+                      parmVarDecl(isAtPosition(0))));
+  EXPECT_TRUE(matches("void x() { [](int a, int b) {}; }",
+                      parmVarDecl(isAtPosition(1))));
+  EXPECT_TRUE(
+      notMatches("void x() { [](int val) {}; }", parmVarDecl(isAtPosition(1))));
+}
+
 TEST(IsArray, Basic) {
   EXPECT_TRUE(matches("struct MyClass {}; MyClass *p1 = new MyClass[10];",
                       cxxNewExpr(isArray())));
Index: clang/lib/AST/ASTContext.cpp
===================================================================
--- clang/lib/AST/ASTContext.cpp
+++ clang/lib/AST/ASTContext.cpp
@@ -10749,6 +10749,13 @@
   return I->second;
 }
 
+bool ASTContext::parameterHasIndex(const ParmVarDecl *D, unsigned index) const {
+  ParameterIndexTable::const_iterator I = ParamIndices.find(D);
+  if (I == ParamIndices.end())
+    return false;
+  return I->second == index;
+}
+
 QualType ASTContext::getStringLiteralArrayType(QualType EltTy,
                                                unsigned Length) const {
   // A C++ string literal has a const-qualified element type (C++ 2.13.4p1).
Index: clang/include/clang/ASTMatchers/ASTMatchers.h
===================================================================
--- clang/include/clang/ASTMatchers/ASTMatchers.h
+++ clang/include/clang/ASTMatchers/ASTMatchers.h
@@ -4615,6 +4615,27 @@
          InnerMatcher.matches(*DeclarationStatement, Finder, Builder);
 }
 
+/// Matches the ParmVarDecl nodes that are at the N'th position in the parameter
+/// list. The parameter list could be that of either a block, function, or
+/// objc-method.
+///
+///
+/// Given
+///
+/// \code
+/// void f(int a, int b, int c) {
+/// }
+/// \endcode
+///
+/// ``parmVarDecl(isAtPosition(0))`` matches ``int a``.
+///
+/// ``parmVarDecl(isAtPosition(1))`` matches ``int b``.
+AST_MATCHER_P(clang::ParmVarDecl, isAtPosition, unsigned, N) {
+  const clang::DeclContext *ParentContext = Node.getParentFunctionOrMethod();
+  return ParentContext != nullptr &&
+         ParentContext->getParentASTContext().parameterHasIndex(&Node, N);
+}
+
 /// Matches the index expression of an array subscript expression.
 ///
 /// Given
Index: clang/include/clang/AST/ASTContext.h
===================================================================
--- clang/include/clang/AST/ASTContext.h
+++ clang/include/clang/AST/ASTContext.h
@@ -2795,6 +2795,10 @@
   /// index of the parameter when it exceeds the size of the normal bitfield.
   unsigned getParameterIndex(const ParmVarDecl *D) const;
 
+  // Returns "true" iff the given ParmVarDecl exists in this context at the
+  // given position.
+  bool parameterHasIndex(const ParmVarDecl *D, unsigned index) const;
+
   /// Return a string representing the human readable name for the specified
   /// function declaration or file name. Used by SourceLocExpr and
   /// PredefinedExpr to cache evaluated results.
Index: clang/docs/LibASTMatchersReference.html
===================================================================
--- clang/docs/LibASTMatchersReference.html
+++ clang/docs/LibASTMatchersReference.html
@@ -4671,6 +4671,23 @@
 Usable as: Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html";>FunctionDecl</a>&gt;, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1VarDecl.html";>VarDecl</a>&gt;, Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1CXXRecordDecl.html";>CXXRecordDecl</a>&gt;
 </pre></td></tr>
 
+
+<tr><td>Matcher&lt;clang::ParmVarDecl&gt;</td><td class="name" onclick="toggle('isAtPosition0')"><a name="isAtPosition0Anchor">isAtPosition</a></td><td>unsigned N</td></tr>
+<tr><td colspan="4" class="doc" id="isAtPosition0"><pre>Matches the ParmVarDecl nodes that are at the N'th position in the parameter
+list. The parameter list could be that of either a block, function, or
+objc-method.
+
+
+Given
+
+void f(int a, int b, int c) {
+}
+
+``parmVarDecl(isAtPosition(0))`` matches ``int a``.
+
+``parmVarDecl(isAtPosition(1))`` matches ``int b``.
+</pre></td></tr>
+
 <!--END_NARROWING_MATCHERS -->
 </table>
 

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