Author: Alex Wang Date: 2026-02-15T15:04:47+01:00 New Revision: 47abe868314d2b2d71d188723bda41ea3d4641f7
URL: https://github.com/llvm/llvm-project/commit/47abe868314d2b2d71d188723bda41ea3d4641f7 DIFF: https://github.com/llvm/llvm-project/commit/47abe868314d2b2d71d188723bda41ea3d4641f7.diff LOG: [clang][CFG] Sequence RHS before LHS for overloaded assignment operators in CFG to match C++17 rules (#181113) Fixes #180521 Added: clang/test/Analysis/cfg-assignment-eval-order.cpp Modified: clang/lib/Analysis/CFG.cpp clang/test/Analysis/missing-bind-temporary.cpp clang/test/Analysis/scopes-cfg-output.cpp Removed: ################################################################################ diff --git a/clang/lib/Analysis/CFG.cpp b/clang/lib/Analysis/CFG.cpp index 1b6cfc716cf93..10a7c5b2c8344 100644 --- a/clang/lib/Analysis/CFG.cpp +++ b/clang/lib/Analysis/CFG.cpp @@ -656,6 +656,7 @@ class CFGBuilder { bool ExternallyDestructed = false); CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); CFGBlock *VisitChildren(Stmt *S); + CFGBlock *VisitCallExprChildren(CallExpr *C); CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc); CFGBlock *VisitOMPExecutableDirective(OMPExecutableDirective *D, AddStmtChoice asc); @@ -731,6 +732,8 @@ class CFGBuilder { CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E, bool ExternallyDestructed, TempDtorContext &Context); + CFGBlock *VisitCXXOperatorCallExprForTemporaryDtors(CXXOperatorCallExpr *E, + TempDtorContext &Context); CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors( CXXBindTemporaryExpr *E, bool ExternallyDestructed, TempDtorContext &Context); CFGBlock *VisitConditionalOperatorForTemporaryDtors( @@ -2542,6 +2545,19 @@ CFGBlock *CFGBuilder::VisitChildren(Stmt *S) { return B; } +CFGBlock *CFGBuilder::VisitCallExprChildren(CallExpr *C) { + // For overloaded assignment operators, visit arguments in reverse order (LHS + // then RHS) so that RHS is sequenced before LHS in the CFG, matching C++17 + // sequencing rules. + if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(C); + OCE && OCE->isAssignmentOp()) { + Visit(OCE->getArg(0)); + Visit(OCE->getArg(1)); + return Visit(OCE->getCallee()); + } + return VisitChildren(C); +} + CFGBlock *CFGBuilder::VisitInitListExpr(InitListExpr *ILE, AddStmtChoice asc) { if (asc.alwaysAdd(*this, ILE)) { autoCreateBlock(); @@ -2879,7 +2895,7 @@ CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { autoCreateBlock(); appendCall(Block, C); - return VisitChildren(C); + return VisitCallExprChildren(C); } if (Block) { @@ -2903,7 +2919,7 @@ CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { addSuccessor(Block, &cfg->getExit()); } - return VisitChildren(C); + return VisitCallExprChildren(C); } CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, @@ -5103,6 +5119,10 @@ CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool ExternallyDestructed, ExternallyDestructed, Context); + case Stmt::CXXOperatorCallExprClass: + return VisitCXXOperatorCallExprForTemporaryDtors( + cast<CXXOperatorCallExpr>(E), Context); + case Stmt::CXXBindTemporaryExprClass: return VisitCXXBindTemporaryExprForTemporaryDtors( cast<CXXBindTemporaryExpr>(E), ExternallyDestructed, Context); @@ -5243,6 +5263,18 @@ CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors( return VisitChildrenForTemporaryDtors(E, ExternallyDestructed, Context); } +CFGBlock *CFGBuilder::VisitCXXOperatorCallExprForTemporaryDtors( + CXXOperatorCallExpr *E, TempDtorContext &Context) { + if (E->isAssignmentOp()) { + // For assignment operators, the RHS expression is evaluated before the LHS + // expression, so prepend temporary destructors for the RHS first. + CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getArg(1), false, Context); + CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getArg(0), false, Context); + return LHSBlock ? LHSBlock : RHSBlock; + } + return VisitChildrenForTemporaryDtors(E, false, Context); +} + CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( CXXBindTemporaryExpr *E, bool ExternallyDestructed, TempDtorContext &Context) { // First add destructors for temporaries in subexpression. diff --git a/clang/test/Analysis/cfg-assignment-eval-order.cpp b/clang/test/Analysis/cfg-assignment-eval-order.cpp new file mode 100644 index 0000000000000..8acf2684aa682 --- /dev/null +++ b/clang/test/Analysis/cfg-assignment-eval-order.cpp @@ -0,0 +1,55 @@ +// RUN: %clang_analyze_cc1 -analyzer-checker=debug.DumpCFG -std=c++17 %s > %t 2>&1 +// RUN: FileCheck --input-file=%t %s + +// CHECK-LABEL: void test_eval_order(Map &m, int a, int b) +// CHECK: 1: operator= +// CHECK-NEXT: 2: [B1.1] (ImplicitCastExpr, FunctionToPointerDecay, Map &(*)(const Map &)) +// CHECK-NEXT: 3: operator[] +// CHECK-NEXT: 4: [B1.3] (ImplicitCastExpr, FunctionToPointerDecay, Map &(*)(int)) +// CHECK-NEXT: 5: m +// CHECK-NEXT: 6: a +// CHECK-NEXT: 7: [B1.6] (ImplicitCastExpr, LValueToRValue, int) +// CHECK-NEXT: 8: [B1.5]{{\[\[}}B1.7]] (OperatorCall) +// CHECK-NEXT: 9: [B1.8] (ImplicitCastExpr, NoOp, const Map) +// CHECK-NEXT: 10: operator[] +// CHECK-NEXT: 11: [B1.10] (ImplicitCastExpr, FunctionToPointerDecay, Map &(*)(int)) +// CHECK-NEXT: 12: m +// CHECK-NEXT: 13: b +// CHECK-NEXT: 14: [B1.13] (ImplicitCastExpr, LValueToRValue, int) +// CHECK-NEXT: 15: [B1.12]{{\[\[}}B1.14]] (OperatorCall) +// CHECK-NEXT: 16: [B1.15] = [B1.9] (OperatorCall) + +struct Map { + Map &operator[](int); + Map &operator=(const Map &); +}; + +void test_eval_order(Map &m, int a, int b) { + m[b] = m[a]; +} + +struct A { + A(); + ~A(); + A &operator=(const A &); +}; + +struct B { + B(); + ~B(); +}; + +struct C { + C(); + ~C(); +}; + +A &getLHS(const B &); +A &getRHS(const C &); + +// CHECK-LABEL: void test_temp_dtor_order() +// CHECK: ~B() (Temporary object destructor) +// CHECK-NEXT: ~C() (Temporary object destructor) +void test_temp_dtor_order() { + getLHS(B()) = getRHS(C()); +} diff --git a/clang/test/Analysis/missing-bind-temporary.cpp b/clang/test/Analysis/missing-bind-temporary.cpp index 3d1af469dc01c..2ce733b0986b0 100644 --- a/clang/test/Analysis/missing-bind-temporary.cpp +++ b/clang/test/Analysis/missing-bind-temporary.cpp @@ -23,11 +23,11 @@ class B { // CHECK-NEXT: 2: B i; // CHECK-NEXT: 3: operator= // CHECK-NEXT: 4: [B1.3] (ImplicitCastExpr, FunctionToPointerDecay, B &(*)(B &&) noexcept) -// CHECK-NEXT: 5: i -// CHECK-NEXT: 6: {} (CXXConstructExpr, [B1.7], [B1.8], B) -// CHECK-NEXT: 7: [B1.6] (BindTemporary) -// CHECK-NEXT: 8: [B1.7] -// CHECK-NEXT: 9: [B1.5] = [B1.8] (OperatorCall) +// CHECK-NEXT: 5: {} (CXXConstructExpr, [B1.6], [B1.7], B) +// CHECK-NEXT: 6: [B1.5] (BindTemporary) +// CHECK-NEXT: 7: [B1.6] +// CHECK-NEXT: 8: i +// CHECK-NEXT: 9: [B1.8] = [B1.7] (OperatorCall) // CHECK-NEXT: 10: ~B() (Temporary object destructor) // CHECK-NEXT: 11: [B1.2].~B() (Implicit destructor) void foo(int) { @@ -60,13 +60,13 @@ class B { // CHECK-NEXT: 2: B i; // CHECK-NEXT: 3: operator= // CHECK-NEXT: 4: [B1.3] (ImplicitCastExpr, FunctionToPointerDecay, B &(*)(B &&) noexcept) -// CHECK-NEXT: 5: i -// CHECK-NEXT: 6: {} (CXXConstructExpr, [B1.7], [B1.8], B) -// CHECK-NEXT: 7: [B1.6] (BindTemporary) -// CHECK-NEXT: 8: [B1.7] -// CHECK-NEXT: 9: [B1.5] = [B1.8] (OperatorCall) -// CHECK-NEXT: 10: ~B() (Temporary object destructor) -// CHECK-NEXT: 11: [B1.2].~B() (Implicit destructor) +// CHECK-NEXT: 5: {} (CXXConstructExpr, [B1.6], [B1.7], B) +// CHECK-NEXT: 6: [B1.5] (BindTemporary) +// CHECK-NEXT: 7: [B1.6] +// CHECK-NEXT: 8: i +// CHECK-NEXT: 9: [B1.8] = [B1.7] (OperatorCall) +// CHECK-NEXT: 10: ~B() (Temporary object destructor) +// CHECK-NEXT: 11: [B1.2].~B() (Implicit destructor) template <typename T> void foo(T) { B i; i = {}; @@ -101,12 +101,12 @@ class B { // CHECK-NEXT: 2: B i; // CHECK-NEXT: 3: operator= // CHECK-NEXT: 4: [B1.3] (ImplicitCastExpr, FunctionToPointerDecay, B &(*)(B &&) noexcept) -// CHECK-NEXT: 5: i +// CHECK-NEXT: 5: {} // CHECK-NEXT: 6: {} -// CHECK-NEXT: 7: {} -// CHECK-NEXT: 8: [B1.7] (BindTemporary) -// CHECK-NEXT: 9: [B1.8] -// CHECK-NEXT: 10: [B1.5] = [B1.9] (OperatorCall) +// CHECK-NEXT: 7: [B1.6] (BindTemporary) +// CHECK-NEXT: 8: [B1.7] +// CHECK-NEXT: 9: i +// CHECK-NEXT: 10: [B1.9] = [B1.8] (OperatorCall) // CHECK-NEXT: 11: ~B() (Temporary object destructor) // CHECK-NEXT: 12: [B1.2].~B() (Implicit destructor) template <typename T> void foo(T) { diff --git a/clang/test/Analysis/scopes-cfg-output.cpp b/clang/test/Analysis/scopes-cfg-output.cpp index 6ed6f3638f75b..ac8ff1179a994 100644 --- a/clang/test/Analysis/scopes-cfg-output.cpp +++ b/clang/test/Analysis/scopes-cfg-output.cpp @@ -907,10 +907,10 @@ void test_for_compound_and_break() { // CHECK-NEXT: 5: auto &i // CHECK-NEXT: 6: operator= // CHECK-NEXT: 7: [B4.6] (ImplicitCastExpr, FunctionToPointerDecay, A &(*)(const A &) -// CHECK-NEXT: 8: i -// CHECK-NEXT: 9: b -// CHECK-NEXT: 10: [B4.9] (ImplicitCastExpr, NoOp, const A) -// CHECK-NEXT: 11: [B4.8] = [B4.10] (OperatorCall) +// CHECK-NEXT: 8: b +// CHECK-NEXT: 9: [B4.8] (ImplicitCastExpr, NoOp, const A) +// CHECK-NEXT: 10: i +// CHECK-NEXT: 11: [B4.10] = [B4.9] (OperatorCall) // CHECK-NEXT: 12: CFGScopeEnd(i) // CHECK-NEXT: Preds (1): B2 // CHECK-NEXT: Succs (1): B3 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
