diff options
| -rw-r--r-- | clang/docs/LibASTMatchersReference.html | 21 | ||||
| -rw-r--r-- | clang/include/clang/ASTMatchers/ASTMatchers.h | 32 | ||||
| -rw-r--r-- | clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp | 17 |
3 files changed, 47 insertions, 23 deletions
diff --git a/clang/docs/LibASTMatchersReference.html b/clang/docs/LibASTMatchersReference.html index 31f71b76ae0..68d536a0704 100644 --- a/clang/docs/LibASTMatchersReference.html +++ b/clang/docs/LibASTMatchersReference.html @@ -5805,14 +5805,15 @@ Example matches x (matcher = expr(hasType(cxxRecordDecl(hasName("X"))))) <tr><td>Matcher<<a href="https://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>></td><td class="name" onclick="toggle('ignoringElidableConstructorCall0')"><a name="ignoringElidableConstructorCall0Anchor">ignoringElidableConstructorCall</a></td><td>ast_matchers::Matcher<<a href="https://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>> InnerMatcher</td></tr> <tr><td colspan="4" class="doc" id="ignoringElidableConstructorCall0"><pre>Matches expressions that match InnerMatcher that are possibly wrapped in an -elidable constructor. +elidable constructor and other corresponding bookkeeping nodes. -In C++17 copy elidable constructors are no longer being -generated in the AST as it is not permitted by the standard. They are -however part of the AST in C++14 and earlier. Therefore, to write a matcher -that works in all language modes, the matcher has to skip elidable -constructor AST nodes if they appear in the AST. This matcher can be used to -skip those elidable constructors. +In C++17, elidable copy constructors are no longer being generated in the +AST as it is not permitted by the standard. They are, however, part of the +AST in C++14 and earlier. So, a matcher must abstract over these differences +to work in all language modes. This matcher skips elidable constructor-call +AST nodes, `ExprWithCleanups` nodes wrapping elidable constructor-calls and +various implicit nodes inside the constructor calls, all of which will not +appear in the C++17 AST. Given @@ -5822,10 +5823,8 @@ void f() { H D = G(); } -``varDecl(hasInitializer(any( - ignoringElidableConstructorCall(callExpr()), - exprWithCleanups(ignoringElidableConstructorCall(callExpr()))))`` -matches ``H D = G()`` +``varDecl(hasInitializer(ignoringElidableConstructorCall(callExpr())))`` +matches ``H D = G()`` in C++11 through C++17 (and beyond). </pre></td></tr> diff --git a/clang/include/clang/ASTMatchers/ASTMatchers.h b/clang/include/clang/ASTMatchers/ASTMatchers.h index 990d25490e3..6bf20ead1b0 100644 --- a/clang/include/clang/ASTMatchers/ASTMatchers.h +++ b/clang/include/clang/ASTMatchers/ASTMatchers.h @@ -6533,14 +6533,15 @@ AST_MATCHER(FunctionDecl, hasTrailingReturn) { } /// Matches expressions that match InnerMatcher that are possibly wrapped in an -/// elidable constructor. +/// elidable constructor and other corresponding bookkeeping nodes. /// -/// In C++17 copy elidable constructors are no longer being -/// generated in the AST as it is not permitted by the standard. They are -/// however part of the AST in C++14 and earlier. Therefore, to write a matcher -/// that works in all language modes, the matcher has to skip elidable -/// constructor AST nodes if they appear in the AST. This matcher can be used to -/// skip those elidable constructors. +/// In C++17, elidable copy constructors are no longer being generated in the +/// AST as it is not permitted by the standard. They are, however, part of the +/// AST in C++14 and earlier. So, a matcher must abstract over these differences +/// to work in all language modes. This matcher skips elidable constructor-call +/// AST nodes, `ExprWithCleanups` nodes wrapping elidable constructor-calls and +/// various implicit nodes inside the constructor calls, all of which will not +/// appear in the C++17 AST. /// /// Given /// @@ -6552,13 +6553,20 @@ AST_MATCHER(FunctionDecl, hasTrailingReturn) { /// } /// \endcode /// -/// ``varDecl(hasInitializer(any( -/// ignoringElidableConstructorCall(callExpr()), -/// exprWithCleanups(ignoringElidableConstructorCall(callExpr()))))`` -/// matches ``H D = G()`` +/// ``varDecl(hasInitializer(ignoringElidableConstructorCall(callExpr())))`` +/// matches ``H D = G()`` in C++11 through C++17 (and beyond). AST_MATCHER_P(Expr, ignoringElidableConstructorCall, ast_matchers::internal::Matcher<Expr>, InnerMatcher) { - if (const auto *CtorExpr = dyn_cast<CXXConstructExpr>(&Node)) { + // E tracks the node that we are examining. + const Expr *E = &Node; + // If present, remove an outer `ExprWithCleanups` corresponding to the + // underlying `CXXConstructExpr`. This check won't cover all cases of added + // `ExprWithCleanups` corresponding to `CXXConstructExpr` nodes (because the + // EWC is placed on the outermost node of the expression, which this may not + // be), but, it still improves the coverage of this matcher. + if (const auto *CleanupsExpr = dyn_cast<ExprWithCleanups>(&Node)) + E = CleanupsExpr->getSubExpr(); + if (const auto *CtorExpr = dyn_cast<CXXConstructExpr>(E)) { if (CtorExpr->isElidable()) { if (const auto *MaterializeTemp = dyn_cast<MaterializeTemporaryExpr>(CtorExpr->getArg(0))) { diff --git a/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp b/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp index cb5cf9ebf52..1b95d3d54ee 100644 --- a/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp +++ b/clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp @@ -671,6 +671,23 @@ TEST(Matcher, IgnoresElidableDoesNotPreventMatches) { LanguageMode::Cxx11OrLater)); } +TEST(Matcher, IgnoresElidableInVarInit) { + auto matcher = + varDecl(hasInitializer(ignoringElidableConstructorCall(callExpr()))); + EXPECT_TRUE(matches("struct H {};" + "H G();" + "void f(H D = G()) {" + " return;" + "}", + matcher, LanguageMode::Cxx11OrLater)); + EXPECT_TRUE(matches("struct H {};" + "H G();" + "void f() {" + " H D = G();" + "}", + matcher, LanguageMode::Cxx11OrLater)); +} + TEST(Matcher, BindTheSameNameInAlternatives) { StatementMatcher matcher = anyOf( binaryOperator(hasOperatorName("+"), |
