[cfe-commits] r172690 - in /cfe/trunk: include/clang/AST/EvaluatedExprVisitor.h include/clang/Basic/DiagnosticGroups.td include/clang/Basic/DiagnosticSemaKinds.td include/clang/Sema/Sema.h lib/Sema/SemaChecking.cpp lib/Sema/SemaDeclCXX.cpp lib/Sema/SemaExpr.cpp lib/Sema/SemaExprCXX.cpp test/SemaCXX/altivec.cpp test/SemaCXX/warn-unsequenced.cpp
David Blaikie
dblaikie at gmail.com
Wed Jan 16 17:27:13 PST 2013
On Wed, Jan 16, 2013 at 5:17 PM, Richard Smith
<richard-llvm at metafoo.co.uk> wrote:
> Author: rsmith
> Date: Wed Jan 16 19:17:56 2013
> New Revision: 172690
>
> URL: http://llvm.org/viewvc/llvm-project?rev=172690&view=rev
> Log:
> Add -Wunsequenced (with compatibility alias -Wsequence-point) to warn on
> expressions which have undefined behavior due to multiple unsequenced
> modifications or an unsequenced modification and use of a variable.
I believe this resolves PR4579. (I've marked it resolved on your behalf)
> Added:
> cfe/trunk/test/SemaCXX/warn-unsequenced.cpp
> Modified:
> cfe/trunk/include/clang/AST/EvaluatedExprVisitor.h
> cfe/trunk/include/clang/Basic/DiagnosticGroups.td
> cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
> cfe/trunk/include/clang/Sema/Sema.h
> cfe/trunk/lib/Sema/SemaChecking.cpp
> cfe/trunk/lib/Sema/SemaDeclCXX.cpp
> cfe/trunk/lib/Sema/SemaExpr.cpp
> cfe/trunk/lib/Sema/SemaExprCXX.cpp
> cfe/trunk/test/SemaCXX/altivec.cpp
>
> Modified: cfe/trunk/include/clang/AST/EvaluatedExprVisitor.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/EvaluatedExprVisitor.h?rev=172690&r1=172689&r2=172690&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/AST/EvaluatedExprVisitor.h (original)
> +++ cfe/trunk/include/clang/AST/EvaluatedExprVisitor.h Wed Jan 16 19:17:56 2013
> @@ -49,6 +49,9 @@
> }
>
> void VisitChooseExpr(ChooseExpr *E) {
> + // Don't visit either child expression if the condition is dependent.
> + if (E->getCond()->isValueDependent())
> + return;
> // Only the selected subexpression matters; the other one is not evaluated.
> return this->Visit(E->getChosenSubExpr(Context));
> }
>
> Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=172690&r1=172689&r2=172690&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
> +++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Wed Jan 16 19:17:56 2013
> @@ -198,7 +198,6 @@
> def SemiBeforeMethodBody : DiagGroup<"semicolon-before-method-body">;
> def Sentinel : DiagGroup<"sentinel">;
> def MissingMethodReturnType : DiagGroup<"missing-method-return-type">;
> -def : DiagGroup<"sequence-point">;
> def Shadow : DiagGroup<"shadow">;
> def Shorten64To32 : DiagGroup<"shorten-64-to-32">;
> def : DiagGroup<"sign-promo">;
> @@ -218,6 +217,10 @@
> def DuplicateDeclSpecifier : DiagGroup<"duplicate-decl-specifier">;
> def CompareDistinctPointerType : DiagGroup<"compare-distinct-pointer-types">;
>
> +def Unsequenced : DiagGroup<"unsequenced">;
> +// GCC name for -Wunsequenced
> +def : DiagGroup<"sequence-point", [Unsequenced]>;
> +
> // Preprocessor warnings.
> def AmbiguousMacro : DiagGroup<"ambiguous-macro">;
>
>
> Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=172690&r1=172689&r2=172690&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
> +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Wed Jan 16 19:17:56 2013
> @@ -1323,6 +1323,11 @@
> "is always %select{false|true}2">;
> def err_init_incomplete_type : Error<"initialization of incomplete type %0">;
>
> +def warn_unsequenced_mod_mod : Warning<
> + "multiple unsequenced modifications to %0">, InGroup<Unsequenced>;
> +def warn_unsequenced_mod_use : Warning<
> + "unsequenced modification and access to %0">, InGroup<Unsequenced>;
> +
> def err_temp_copy_no_viable : Error<
> "no viable constructor %select{copying variable|copying parameter|"
> "returning object|throwing object|copying member subobject|copying array "
>
> Modified: cfe/trunk/include/clang/Sema/Sema.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=172690&r1=172689&r2=172690&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Sema/Sema.h (original)
> +++ cfe/trunk/include/clang/Sema/Sema.h Wed Jan 16 19:17:56 2013
> @@ -7319,6 +7319,11 @@
> SourceLocation ReturnLoc);
> void CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr* RHS);
> void CheckImplicitConversions(Expr *E, SourceLocation CC = SourceLocation());
> + void CheckUnsequencedOperations(Expr *E);
> +
> + /// \brief Perform semantic checks on a completed expression. This will either
> + /// be a full-expression or a default argument expression.
> + void CheckCompletedExpr(Expr *E, SourceLocation CheckLoc = SourceLocation());
>
> void CheckBitFieldInitialization(SourceLocation InitLoc, FieldDecl *Field,
> Expr *Init);
>
> Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=172690&r1=172689&r2=172690&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaChecking.cpp Wed Jan 16 19:17:56 2013
> @@ -5171,6 +5171,424 @@
> AnalyzeImplicitConversions(*this, E, CC);
> }
>
> +namespace {
> +/// \brief Visitor for expressions which looks for unsequenced operations on the
> +/// same object.
> +class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> {
> + /// \brief A tree of sequenced regions within an expression. Two regions are
> + /// unsequenced if one is an ancestor or a descendent of the other. When we
> + /// finish processing an expression with sequencing, such as a comma
> + /// expression, we fold its tree nodes into its parent, since they are
> + /// unsequenced with respect to nodes we will visit later.
> + class SequenceTree {
> + struct Value {
> + explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {}
> + unsigned Parent : 31;
> + bool Merged : 1;
> + };
> + llvm::SmallVector<Value, 8> Values;
> +
> + public:
> + /// \brief A region within an expression which may be sequenced with respect
> + /// to some other region.
> + class Seq {
> + explicit Seq(unsigned N) : Index(N) {}
> + unsigned Index;
> + friend class SequenceTree;
> + public:
> + Seq() : Index(0) {}
> + };
> +
> + SequenceTree() { Values.push_back(Value(0)); }
> + Seq root() const { return Seq(0); }
> +
> + /// \brief Create a new sequence of operations, which is an unsequenced
> + /// subset of \p Parent. This sequence of operations is sequenced with
> + /// respect to other children of \p Parent.
> + Seq allocate(Seq Parent) {
> + Values.push_back(Value(Parent.Index));
> + return Seq(Values.size() - 1);
> + }
> +
> + /// \brief Merge a sequence of operations into its parent.
> + void merge(Seq S) {
> + Values[S.Index].Merged = true;
> + }
> +
> + /// \brief Determine whether two operations are unsequenced. This operation
> + /// is asymmetric: \p Cur should be the more recent sequence, and \p Old
> + /// should have been merged into its parent as appropriate.
> + bool isUnsequenced(Seq Cur, Seq Old) {
> + unsigned C = representative(Cur.Index);
> + unsigned Target = representative(Old.Index);
> + while (C >= Target) {
> + if (C == Target)
> + return true;
> + C = Values[C].Parent;
> + }
> + return false;
> + }
> +
> + private:
> + /// \brief Pick a representative for a sequence.
> + unsigned representative(unsigned K) {
> + if (Values[K].Merged)
> + // Perform path compression as we go.
> + return Values[K].Parent = representative(Values[K].Parent);
> + return K;
> + }
> + };
> +
> + /// An object for which we can track unsequenced uses.
> + typedef NamedDecl *Object;
> +
> + /// Different flavors of object usage which we track. We only track the
> + /// least-sequenced usage of each kind.
> + enum UsageKind {
> + /// A read of an object. Multiple unsequenced reads are OK.
> + UK_Use,
> + /// A modification of an object which is sequenced before the value
> + /// computation of the expression, such as ++n.
> + UK_ModAsValue,
> + /// A modification of an object which is not sequenced before the value
> + /// computation of the expression, such as n++.
> + UK_ModAsSideEffect,
> +
> + UK_Count = UK_ModAsSideEffect + 1
> + };
> +
> + struct Usage {
> + Usage() : Use(0), Seq() {}
> + Expr *Use;
> + SequenceTree::Seq Seq;
> + };
> +
> + struct UsageInfo {
> + UsageInfo() : Diagnosed(false) {}
> + Usage Uses[UK_Count];
> + /// Have we issued a diagnostic for this variable already?
> + bool Diagnosed;
> + };
> + typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap;
> +
> + Sema &SemaRef;
> + /// Sequenced regions within the expression.
> + SequenceTree Tree;
> + /// Declaration modifications and references which we have seen.
> + UsageInfoMap UsageMap;
> + /// The region we are currently within.
> + SequenceTree::Seq Region;
> + /// Filled in with declarations which were modified as a side-effect
> + /// (that is, post-increment operations).
> + llvm::SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect;
> +
> + /// RAII object wrapping the visitation of a sequenced subexpression of an
> + /// expression. At the end of this process, the side-effects of the evaluation
> + /// become sequenced with respect to the value computation of the result, so
> + /// we downgrade any UK_ModAsSideEffect within the evaluation to
> + /// UK_ModAsValue.
> + struct SequencedSubexpression {
> + SequencedSubexpression(SequenceChecker &Self)
> + : Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) {
> + Self.ModAsSideEffect = &ModAsSideEffect;
> + }
> + ~SequencedSubexpression() {
> + for (unsigned I = 0, E = ModAsSideEffect.size(); I != E; ++I) {
> + UsageInfo &U = Self.UsageMap[ModAsSideEffect[I].first];
> + U.Uses[UK_ModAsSideEffect] = ModAsSideEffect[I].second;
> + Self.addUsage(U, ModAsSideEffect[I].first,
> + ModAsSideEffect[I].second.Use, UK_ModAsValue);
> + }
> + Self.ModAsSideEffect = OldModAsSideEffect;
> + }
> +
> + SequenceChecker &Self;
> + llvm::SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect;
> + llvm::SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect;
> + };
> +
> + /// \brief Find the object which is produced by the specified expression,
> + /// if any.
> + Object getObject(Expr *E, bool Mod) const {
> + E = E->IgnoreParenCasts();
> + if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
> + if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec))
> + return getObject(UO->getSubExpr(), Mod);
> + } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
> + if (BO->getOpcode() == BO_Comma)
> + return getObject(BO->getRHS(), Mod);
> + if (Mod && BO->isAssignmentOp())
> + return getObject(BO->getLHS(), Mod);
> + } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
> + // FIXME: Check for more interesting cases, like "x.n = ++x.n".
> + if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts()))
> + return ME->getMemberDecl();
> + } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
> + // FIXME: If this is a reference, map through to its value.
> + return DRE->getDecl();
> + return 0;
> + }
> +
> + /// \brief Note that an object was modified or used by an expression.
> + void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) {
> + Usage &U = UI.Uses[UK];
> + if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) {
> + if (UK == UK_ModAsSideEffect && ModAsSideEffect)
> + ModAsSideEffect->push_back(std::make_pair(O, U));
> + U.Use = Ref;
> + U.Seq = Region;
> + }
> + }
> + /// \brief Check whether a modification or use conflicts with a prior usage.
> + void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind,
> + bool IsModMod) {
> + if (UI.Diagnosed)
> + return;
> +
> + const Usage &U = UI.Uses[OtherKind];
> + if (!U.Use || !Tree.isUnsequenced(Region, U.Seq))
> + return;
> +
> + Expr *Mod = U.Use;
> + Expr *ModOrUse = Ref;
> + if (OtherKind == UK_Use)
> + std::swap(Mod, ModOrUse);
> +
> + SemaRef.Diag(Mod->getExprLoc(),
> + IsModMod ? diag::warn_unsequenced_mod_mod
> + : diag::warn_unsequenced_mod_use)
> + << O << SourceRange(ModOrUse->getExprLoc());
> + UI.Diagnosed = true;
> + }
> +
> + void notePreUse(Object O, Expr *Use) {
> + UsageInfo &U = UsageMap[O];
> + // Uses conflict with other modifications.
> + checkUsage(O, U, Use, UK_ModAsValue, false);
> + }
> + void notePostUse(Object O, Expr *Use) {
> + UsageInfo &U = UsageMap[O];
> + checkUsage(O, U, Use, UK_ModAsSideEffect, false);
> + addUsage(U, O, Use, UK_Use);
> + }
> +
> + void notePreMod(Object O, Expr *Mod) {
> + UsageInfo &U = UsageMap[O];
> + // Modifications conflict with other modifications and with uses.
> + checkUsage(O, U, Mod, UK_ModAsValue, true);
> + checkUsage(O, U, Mod, UK_Use, false);
> + }
> + void notePostMod(Object O, Expr *Use, UsageKind UK) {
> + UsageInfo &U = UsageMap[O];
> + checkUsage(O, U, Use, UK_ModAsSideEffect, true);
> + addUsage(U, O, Use, UK);
> + }
> +
> +public:
> + SequenceChecker(Sema &S, Expr *E)
> + : EvaluatedExprVisitor(S.Context), SemaRef(S), Region(Tree.root()),
> + ModAsSideEffect(0) {
> + Visit(E);
> + }
> +
> + void VisitStmt(Stmt *S) {
> + // Skip all statements which aren't expressions for now.
> + }
> +
> + void VisitExpr(Expr *E) {
> + // By default, just recurse to evaluated subexpressions.
> + EvaluatedExprVisitor::VisitStmt(E);
> + }
> +
> + void VisitCastExpr(CastExpr *E) {
> + Object O = Object();
> + if (E->getCastKind() == CK_LValueToRValue)
> + O = getObject(E->getSubExpr(), false);
> +
> + if (O)
> + notePreUse(O, E);
> + VisitExpr(E);
> + if (O)
> + notePostUse(O, E);
> + }
> +
> + void VisitBinComma(BinaryOperator *BO) {
> + // C++11 [expr.comma]p1:
> + // Every value computation and side effect associated with the left
> + // expression is sequenced before every value computation and side
> + // effect associated with the right expression.
> + SequenceTree::Seq LHS = Tree.allocate(Region);
> + SequenceTree::Seq RHS = Tree.allocate(Region);
> + SequenceTree::Seq OldRegion = Region;
> +
> + {
> + SequencedSubexpression SeqLHS(*this);
> + Region = LHS;
> + Visit(BO->getLHS());
> + }
> +
> + Region = RHS;
> + Visit(BO->getRHS());
> +
> + Region = OldRegion;
> +
> + // Forget that LHS and RHS are sequenced. They are both unsequenced
> + // with respect to other stuff.
> + Tree.merge(LHS);
> + Tree.merge(RHS);
> + }
> +
> + void VisitBinAssign(BinaryOperator *BO) {
> + // The modification is sequenced after the value computation of the LHS
> + // and RHS, so check it before inspecting the operands and update the
> + // map afterwards.
> + Object O = getObject(BO->getLHS(), true);
> + if (!O)
> + return VisitExpr(BO);
> +
> + notePreMod(O, BO);
> +
> + // C++11 [expr.ass]p7:
> + // E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated
> + // only once.
> + //
> + // Therefore, for a compound assignment operator, O is considered used
> + // everywhere except within the evaluation of E1 itself.
> + if (isa<CompoundAssignOperator>(BO))
> + notePreUse(O, BO);
> +
> + Visit(BO->getLHS());
> +
> + if (isa<CompoundAssignOperator>(BO))
> + notePostUse(O, BO);
> +
> + Visit(BO->getRHS());
> +
> + notePostMod(O, BO, UK_ModAsValue);
> + }
> + void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) {
> + VisitBinAssign(CAO);
> + }
> +
> + void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); }
> + void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); }
> + void VisitUnaryPreIncDec(UnaryOperator *UO) {
> + Object O = getObject(UO->getSubExpr(), true);
> + if (!O)
> + return VisitExpr(UO);
> +
> + notePreMod(O, UO);
> + Visit(UO->getSubExpr());
> + notePostMod(O, UO, UK_ModAsValue);
> + }
> +
> + void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); }
> + void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); }
> + void VisitUnaryPostIncDec(UnaryOperator *UO) {
> + Object O = getObject(UO->getSubExpr(), true);
> + if (!O)
> + return VisitExpr(UO);
> +
> + notePreMod(O, UO);
> + Visit(UO->getSubExpr());
> + notePostMod(O, UO, UK_ModAsSideEffect);
> + }
> +
> + /// Don't visit the RHS of '&&' or '||' if it might not be evaluated.
> + void VisitBinLOr(BinaryOperator *BO) {
> + // The side-effects of the LHS of an '&&' are sequenced before the
> + // value computation of the RHS, and hence before the value computation
> + // of the '&&' itself, unless the LHS evaluates to zero. We treat them
> + // as if they were unconditionally sequenced.
> + {
> + SequencedSubexpression Sequenced(*this);
> + Visit(BO->getLHS());
> + }
> +
> + bool Result;
> + if (!BO->getLHS()->isValueDependent() &&
> + BO->getLHS()->EvaluateAsBooleanCondition(Result, SemaRef.Context) &&
> + !Result)
> + Visit(BO->getRHS());
> + }
> + void VisitBinLAnd(BinaryOperator *BO) {
> + {
> + SequencedSubexpression Sequenced(*this);
> + Visit(BO->getLHS());
> + }
> +
> + bool Result;
> + if (!BO->getLHS()->isValueDependent() &&
> + BO->getLHS()->EvaluateAsBooleanCondition(Result, SemaRef.Context) &&
> + Result)
> + Visit(BO->getRHS());
> + }
> +
> + // Only visit the condition, unless we can be sure which subexpression will
> + // be chosen.
> + void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) {
> + SequencedSubexpression Sequenced(*this);
> + Visit(CO->getCond());
> +
> + bool Result;
> + if (!CO->getCond()->isValueDependent() &&
> + CO->getCond()->EvaluateAsBooleanCondition(Result, SemaRef.Context))
> + Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr());
> + }
> +
> + void VisitCXXConstructExpr(CXXConstructExpr *CCE) {
> + if (!CCE->isListInitialization())
> + return VisitExpr(CCE);
> +
> + // In C++11, list initializations are sequenced.
> + llvm::SmallVector<SequenceTree::Seq, 32> Elts;
> + SequenceTree::Seq Parent = Region;
> + for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(),
> + E = CCE->arg_end();
> + I != E; ++I) {
> + Region = Tree.allocate(Parent);
> + Elts.push_back(Region);
> + Visit(*I);
> + }
> +
> + // Forget that the initializers are sequenced.
> + Region = Parent;
> + for (unsigned I = 0; I < Elts.size(); ++I)
> + Tree.merge(Elts[I]);
> + }
> +
> + void VisitInitListExpr(InitListExpr *ILE) {
> + if (!SemaRef.getLangOpts().CPlusPlus11)
> + return VisitExpr(ILE);
> +
> + // In C++11, list initializations are sequenced.
> + llvm::SmallVector<SequenceTree::Seq, 32> Elts;
> + SequenceTree::Seq Parent = Region;
> + for (unsigned I = 0; I < ILE->getNumInits(); ++I) {
> + Expr *E = ILE->getInit(I);
> + if (!E) continue;
> + Region = Tree.allocate(Parent);
> + Elts.push_back(Region);
> + Visit(E);
> + }
> +
> + // Forget that the initializers are sequenced.
> + Region = Parent;
> + for (unsigned I = 0; I < Elts.size(); ++I)
> + Tree.merge(Elts[I]);
> + }
> +};
> +}
> +
> +void Sema::CheckUnsequencedOperations(Expr *E) {
> + SequenceChecker(*this, E);
> +}
> +
> +void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc) {
> + CheckImplicitConversions(E, CheckLoc);
> + CheckUnsequencedOperations(E);
> +}
> +
> void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
> FieldDecl *BitField,
> Expr *Init) {
>
> Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=172690&r1=172689&r2=172690&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Wed Jan 16 19:17:56 2013
> @@ -252,7 +252,7 @@
> return true;
> Arg = Result.takeAs<Expr>();
>
> - CheckImplicitConversions(Arg, EqualLoc);
> + CheckCompletedExpr(Arg, EqualLoc);
> Arg = MaybeCreateExprWithCleanups(Arg);
>
> // Okay: add the default argument to the parameter
>
> Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=172690&r1=172689&r2=172690&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaExpr.cpp Wed Jan 16 19:17:56 2013
> @@ -3534,7 +3534,7 @@
> return ExprError();
>
> Expr *Arg = Result.takeAs<Expr>();
> - CheckImplicitConversions(Arg, Param->getOuterLocStart());
> + CheckCompletedExpr(Arg, Param->getOuterLocStart());
> // Build the default argument expression.
> return Owned(CXXDefaultArgExpr::Create(Context, CallLoc, Param, Arg));
> }
>
> Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=172690&r1=172689&r2=172690&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Wed Jan 16 19:17:56 2013
> @@ -18,6 +18,7 @@
> #include "clang/AST/CXXInheritance.h"
> #include "clang/AST/CharUnits.h"
> #include "clang/AST/DeclObjC.h"
> +#include "clang/AST/EvaluatedExprVisitor.h"
> #include "clang/AST/ExprCXX.h"
> #include "clang/AST/ExprObjC.h"
> #include "clang/AST/TypeLoc.h"
> @@ -5496,7 +5497,7 @@
> return ExprError();
> }
>
> - CheckImplicitConversions(FullExpr.get(), CC);
> + CheckCompletedExpr(FullExpr.get(), CC);
> return MaybeCreateExprWithCleanups(FullExpr);
> }
>
>
> Modified: cfe/trunk/test/SemaCXX/altivec.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/altivec.cpp?rev=172690&r1=172689&r2=172690&view=diff
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/altivec.cpp (original)
> +++ cfe/trunk/test/SemaCXX/altivec.cpp Wed Jan 16 19:17:56 2013
> @@ -62,7 +62,7 @@
> vector float vf;
> vf++;
>
> - ++vi=vi;
> + ++vi=vi; // expected-warning {{unsequenced}}
> (++vi)[1]=1;
> template_f(vi);
> }
>
> Added: cfe/trunk/test/SemaCXX/warn-unsequenced.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-unsequenced.cpp?rev=172690&view=auto
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/warn-unsequenced.cpp (added)
> +++ cfe/trunk/test/SemaCXX/warn-unsequenced.cpp Wed Jan 16 19:17:56 2013
> @@ -0,0 +1,91 @@
> +// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -Wno-unused %s
> +
> +int f(int, int);
> +
> +struct A {
> + int x, y;
> +};
> +struct S {
> + S(int, int);
> +};
> +
> +void test() {
> + int a;
> + int xs[10];
> + ++a = 0; // ok
> + a + ++a; // expected-warning {{unsequenced modification and access to 'a'}}
> + a = ++a; // ok
> + a + a++; // expected-warning {{unsequenced modification and access to 'a'}}
> + a = a++; // expected-warning {{multiple unsequenced modifications to 'a'}}
> + ++ ++a; // ok
> + (a++, a++); // ok
> + ++a + ++a; // expected-warning {{multiple unsequenced modifications to 'a'}}
> + a++ + a++; // expected-warning {{multiple unsequenced modifications}}
> + (a++, a) = 0; // ok, increment is sequenced before value computation of LHS
> + a = xs[++a]; // ok
> + a = xs[a++]; // expected-warning {{multiple unsequenced modifications}}
> + (a ? xs[0] : xs[1]) = ++a; // expected-warning {{unsequenced modification and access}}
> + a = (++a, ++a); // ok
> + a = (a++, ++a); // ok
> + a = (a++, a++); // expected-warning {{multiple unsequenced modifications}}
> + f(a, a); // ok
> + f(a = 0, a); // expected-warning {{unsequenced modification and access}}
> + f(a, a += 0); // expected-warning {{unsequenced modification and access}}
> + f(a = 0, a = 0); // expected-warning {{multiple unsequenced modifications}}
> +
> + // Compound assignment "A OP= B" is equivalent to "A = A OP B" except that A
> + // is evaluated only once.
> + (++a, a) = 1; // ok
> + (++a, a) += 1; // ok
> + a = ++a; // ok
> + a += ++a; // expected-warning {{unsequenced modification and access}}
> +
> + A agg1 = { a++, a++ }; // ok
> + A agg2 = { a++ + a, a++ }; // expected-warning {{unsequenced modification and access}}
> +
> + S str1(a++, a++); // expected-warning {{multiple unsequenced modifications}}
> + S str2 = { a++, a++ }; // ok
> + S str3 = { a++ + a, a++ }; // expected-warning {{unsequenced modification and access}}
> +
> + (xs[2] && (a = 0)) + a; // ok
> + (0 && (a = 0)) + a; // ok
> + (1 && (a = 0)) + a; // expected-warning {{unsequenced modification and access}}
> +
> + (xs[3] || (a = 0)) + a; // ok
> + (0 || (a = 0)) + a; // expected-warning {{unsequenced modification and access}}
> + (1 || (a = 0)) + a; // ok
> +
> + (xs[4] ? a : ++a) + a; // ok
> + (0 ? a : ++a) + a; // expected-warning {{unsequenced modification and access}}
> + (1 ? a : ++a) + a; // ok
> + (xs[5] ? ++a : ++a) + a; // FIXME: warn here
> +
> + (++a, xs[6] ? ++a : 0) + a; // expected-warning {{unsequenced modification and access}}
> +
> + // Here, the read of the fourth 'a' might happen before or after the write to
> + // the second 'a'.
> + a += (a++, a) + a; // expected-warning {{unsequenced modification and access}}
> +
> + int *p = xs;
> + a = *(a++, p); // ok
> + a = a++ && a; // ok
> +
> + A *q = &agg1;
> + (q = &agg2)->y = q->x; // expected-warning {{unsequenced modification and access to 'q'}}
> +
> + // This has undefined behavior if a == 0; otherwise, the side-effect of the
> + // increment is sequenced before the value computation of 'f(a, a)', which is
> + // sequenced before the value computation of the '&&', which is sequenced
> + // before the assignment. We treat the sequencing in '&&' as being
> + // unconditional.
> + a = a++ && f(a, a);
> +
> + // This has undefined behavior if a != 0. FIXME: We should diagnose this.
> + (a && a++) + a;
> +
> + (xs[7] && ++a) * (!xs[7] && ++a); // ok
> +
> + xs[0] = (a = 1, a); // ok
> + (a -= 128) &= 128; // ok
> + ++a += 1; // ok
> +}
>
>
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