r368319 - [clang] Update `ignoringElidableConstructorCall` matcher to ignore `ExprWithCleanups`.
Yitzhak Mandelbaum via cfe-commits
cfe-commits at lists.llvm.org
Thu Aug 8 10:41:45 PDT 2019
Author: ymandel
Date: Thu Aug 8 10:41:44 2019
New Revision: 368319
URL: http://llvm.org/viewvc/llvm-project?rev=368319&view=rev
Log:
[clang] Update `ignoringElidableConstructorCall` matcher to ignore `ExprWithCleanups`.
Summary:
The `ExprWithCleanups` node is added to the AST along with the elidable
CXXConstructExpr. If it is the outermost node of the node being matched, ignore
it as well.
Reviewers: gribozavr
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D65944
Modified:
cfe/trunk/docs/LibASTMatchersReference.html
cfe/trunk/include/clang/ASTMatchers/ASTMatchers.h
cfe/trunk/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
Modified: cfe/trunk/docs/LibASTMatchersReference.html
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/LibASTMatchersReference.html?rev=368319&r1=368318&r2=368319&view=diff
==============================================================================
--- cfe/trunk/docs/LibASTMatchersReference.html (original)
+++ cfe/trunk/docs/LibASTMatchersReference.html Thu Aug 8 10:41:44 2019
@@ -5805,14 +5805,15 @@ Example matches x (matcher = expr(hasTyp
<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>
Modified: cfe/trunk/include/clang/ASTMatchers/ASTMatchers.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/ASTMatchers/ASTMatchers.h?rev=368319&r1=368318&r2=368319&view=diff
==============================================================================
--- cfe/trunk/include/clang/ASTMatchers/ASTMatchers.h (original)
+++ cfe/trunk/include/clang/ASTMatchers/ASTMatchers.h Thu Aug 8 10:41:44 2019
@@ -6533,14 +6533,15 @@ AST_MATCHER(FunctionDecl, hasTrailingRet
}
/// 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, hasTrailingRet
/// }
/// \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))) {
Modified: cfe/trunk/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp?rev=368319&r1=368318&r2=368319&view=diff
==============================================================================
--- cfe/trunk/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp (original)
+++ cfe/trunk/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp Thu Aug 8 10:41:44 2019
@@ -671,6 +671,23 @@ TEST(Matcher, IgnoresElidableDoesNotPrev
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("+"),
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