djtodoro created this revision.
djtodoro added reviewers: shuaiwang, lebedev.ri.
Herald added subscribers: Charusso, jdoerfert, dkrupp, donat.nagy, Szelethus,
mikhail.ramalho, a.sidorin, szepet, baloghadamsoftware, xazax.hun.
We should track mutation of a variable within a comma operator expression.
Current code in `ExprMutationAnalyzer `does not handle it.
This will handle cases like:
`(a, b) ++` < == `b `is modified
`(a, b) = c` < == `b `is modifed
https://reviews.llvm.org/D58894
Files:
include/clang/AST/Expr.h
lib/Analysis/ExprMutationAnalyzer.cpp
unittests/Analysis/ExprMutationAnalyzerTest.cpp
Index: unittests/Analysis/ExprMutationAnalyzerTest.cpp
===================================================================
--- unittests/Analysis/ExprMutationAnalyzerTest.cpp
+++ unittests/Analysis/ExprMutationAnalyzerTest.cpp
@@ -881,6 +881,24 @@
EXPECT_FALSE(isMutated(Results, AST.get()));
}
+TEST(ExprMutationAnalyzerTest, CommaExprWithAnAssigment) {
+ const auto AST =
+ buildASTFromCodeWithArgs("void f() { int x; int y; (x, y) = 5; }",
+ {"-Wno-unused-value"});
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("y")), AST->getASTContext());
+ EXPECT_TRUE(isMutated(Results, AST.get()));
+}
+
+TEST(ExprMutationAnalyzerTest, CommaExprWithDecOp) {
+ const auto AST =
+ buildASTFromCodeWithArgs("void f() { int x; int y; (x, y)++; }",
+ {"-Wno-unused-value"});
+ const auto Results =
+ match(withEnclosingCompound(declRefTo("y")), AST->getASTContext());
+ EXPECT_TRUE(isMutated(Results, AST.get()));
+}
+
TEST(ExprMutationAnalyzerTest, LambdaDefaultCaptureByValue) {
const auto AST = buildASTFromCode("void f() { int x; [=]() { x; }; }");
const auto Results =
Index: lib/Analysis/ExprMutationAnalyzer.cpp
===================================================================
--- lib/Analysis/ExprMutationAnalyzer.cpp
+++ lib/Analysis/ExprMutationAnalyzer.cpp
@@ -14,6 +14,42 @@
namespace {
+// Assignment on an expression with comma operator.
+// Match situations like:
+// '(a, b) = c', '(c, (a, b)) = c', etc.
+AST_MATCHER_P(BinaryOperator, isAssigmentWithCommma, const Expr *, E) {
+ if (Node.isAssignmentOp()) {
+ const Expr* LHSResult = Node.getLHS();
+ while (const auto *BOComma =
+ dyn_cast_or_null<BinaryOperator>(LHSResult->IgnoreParens())) {
+ if (!BOComma->isCommaOp())
+ break;
+ LHSResult = BOComma->getRHS();
+ }
+ if (LHSResult == E)
+ return true;
+ }
+ return false;
+}
+
+// Increment/Decrement on an expression with comma operator.
+// Match situations like:
+// '(a, b)++', '(c, (a, b))++', '(a, b)--', etc.
+AST_MATCHER_P(UnaryOperator, isIncDecOperandWithComma, const Expr *, E) {
+ if (Node.isIncrementDecrementOp()) {
+ const Expr* Result = Node.getSubExpr()->IgnoreParens();
+ while (const auto *BOComma =
+ dyn_cast_or_null<BinaryOperator>(Result->IgnoreParens())) {
+ if (!BOComma->isCommaOp())
+ break;
+ Result = BOComma->getRHS();
+ }
+ if (Result == E)
+ return true;
+ }
+ return false;
+}
+
AST_MATCHER_P(LambdaExpr, hasCaptureInit, const Expr *, E) {
return llvm::is_contained(Node.capture_inits(), E);
}
@@ -195,11 +231,20 @@
const auto AsAssignmentLhs =
binaryOperator(isAssignmentOperator(), hasLHS(equalsNode(Exp)));
+ // LHS of assignment is an expression with comma operator.
+ const auto AsAssignmentCommaLhs =
+ binaryOperator(isAssigmentWithCommma(Exp));
+
// Operand of increment/decrement operators.
const auto AsIncDecOperand =
unaryOperator(anyOf(hasOperatorName("++"), hasOperatorName("--")),
hasUnaryOperand(equalsNode(Exp)));
+ // Operand of increment/decrement operators is an expression
+ // with comma operator.
+ const auto AsIncDecOperandWithComma =
+ unaryOperator(isIncDecOperandWithComma(Exp));
+
// Invoking non-const member function.
// A member function is assumed to be non-const when it is unresolved.
const auto NonConstMethod = cxxMethodDecl(unless(isConst()));
@@ -264,10 +309,12 @@
const auto AsNonConstRefReturn = returnStmt(hasReturnValue(equalsNode(Exp)));
const auto Matches =
- match(findAll(stmt(anyOf(AsAssignmentLhs, AsIncDecOperand, AsNonConstThis,
- AsAmpersandOperand, AsPointerFromArrayDecay,
- AsOperatorArrowThis, AsNonConstRefArg,
- AsLambdaRefCaptureInit, AsNonConstRefReturn))
+ match(findAll(stmt(anyOf(AsAssignmentLhs, AsAssignmentCommaLhs,
+ AsIncDecOperand, AsIncDecOperandWithComma,
+ AsNonConstThis, AsAmpersandOperand,
+ AsPointerFromArrayDecay, AsOperatorArrowThis,
+ AsNonConstRefArg, AsLambdaRefCaptureInit,
+ AsNonConstRefReturn))
.bind("stmt")),
Stm, Context);
return selectFirst<Stmt>("stmt", Matches);
Index: include/clang/AST/Expr.h
===================================================================
--- include/clang/AST/Expr.h
+++ include/clang/AST/Expr.h
@@ -3403,6 +3403,9 @@
static bool isComparisonOp(Opcode Opc) { return Opc >= BO_Cmp && Opc<=BO_NE; }
bool isComparisonOp() const { return isComparisonOp(getOpcode()); }
+ static bool isCommaOp(Opcode Opc) { return Opc == BO_Comma; }
+ bool isCommaOp() const { return isCommaOp(getOpcode()); }
+
static Opcode negateComparisonOp(Opcode Opc) {
switch (Opc) {
default:
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