rtrieu created this revision.
rtrieu added a subscriber: cfe-commits.
Track whether the initialization came from a GNU statement expression. If it
does, prevent the -Wpessiming-move warning from being emitted since the
suggested fix can cause a compile error.
Fix for https://llvm.org/bugs/show_bug.cgi?id=25640
http://reviews.llvm.org/D15255
Files:
include/clang/Sema/Initialization.h
lib/Sema/SemaExpr.cpp
lib/Sema/SemaInit.cpp
test/SemaCXX/warn-pessmizing-move.cpp
Index: test/SemaCXX/warn-pessmizing-move.cpp
===================================================================
--- test/SemaCXX/warn-pessmizing-move.cpp
+++ test/SemaCXX/warn-pessmizing-move.cpp
@@ -227,3 +227,22 @@
test2<B, A>();
}
}
+
+// Don't warn on GNU statement expressions.
+namespace GNU {
+ class A {};
+ class B {
+ public:
+ B();
+ B(B &&);
+ private:
+ B(const B &);
+ };
+
+ void test() {
+ A a = ({auto a = A(); std::move(a); });
+ B b = ({auto b = B(); std::move(b); });
+ }
+
+ auto b = std::move(B());
+}
Index: lib/Sema/SemaInit.cpp
===================================================================
--- lib/Sema/SemaInit.cpp
+++ lib/Sema/SemaInit.cpp
@@ -2887,6 +2887,34 @@
return false;
}
+bool InitializedEntity::isGNUStatementExpression() const {
+ switch (getKind()) {
+ case EK_Result:
+ return LocAndNRVO.GNUStatementExpression;
+
+ case EK_Exception:
+ case EK_Variable:
+ case EK_Parameter:
+ case EK_Parameter_CF_Audited:
+ case EK_Member:
+ case EK_New:
+ case EK_Temporary:
+ case EK_CompoundLiteralInit:
+ case EK_Base:
+ case EK_Delegating:
+ case EK_ArrayElement:
+ case EK_VectorElement:
+ case EK_ComplexElement:
+ case EK_BlockElement:
+ case EK_LambdaCapture:
+ case EK_RelatedResult:
+ break;
+ }
+
+ return false;
+}
+
+
unsigned InitializedEntity::dumpImpl(raw_ostream &OS) const {
assert(getParent() != this);
unsigned Depth = getParent() ? getParent()->dumpImpl(OS) : 0;
@@ -6771,8 +6799,9 @@
// Check for std::move on construction.
if (const Expr *E = CurInit.get()) {
- CheckMoveOnConstruction(S, E,
- Entity.getKind() == InitializedEntity::EK_Result);
+ if (!Entity.isGNUStatementExpression())
+ CheckMoveOnConstruction(S, E,
+ Entity.getKind() == InitializedEntity::EK_Result);
}
return CurInit;
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -11149,11 +11149,8 @@
LastExpr = rebuiltLastStmt;
} else {
LastExpr = PerformCopyInitialization(
- InitializedEntity::InitializeResult(LPLoc,
- Ty,
- false),
- SourceLocation(),
- LastExpr);
+ InitializedEntity::InitializeResult(LPLoc, Ty, false, true),
+ SourceLocation(), LastExpr);
}
if (LastExpr.isInvalid())
Index: include/clang/Sema/Initialization.h
===================================================================
--- include/clang/Sema/Initialization.h
+++ include/clang/Sema/Initialization.h
@@ -116,6 +116,10 @@
/// \brief Whether the entity being initialized may end up using the
/// named return value optimization (NRVO).
bool NRVO;
+
+ /// \brief Whether the initialization is from the last expression of
+ /// a GNU statement expression.
+ bool GNUStatementExpression;
};
struct C {
@@ -169,11 +173,12 @@
/// function, throwing an object, performing an explicit cast, or
/// initializing a parameter for which there is no declaration.
InitializedEntity(EntityKind Kind, SourceLocation Loc, QualType Type,
- bool NRVO = false)
+ bool NRVO = false, bool GNUStatementExpression = false)
: Kind(Kind), Parent(nullptr), Type(Type), ManglingNumber(0)
{
LocAndNRVO.Location = Loc.getRawEncoding();
LocAndNRVO.NRVO = NRVO;
+ LocAndNRVO.GNUStatementExpression = GNUStatementExpression;
}
/// \brief Create the initialization entity for a member subobject.
@@ -238,9 +243,11 @@
}
/// \brief Create the initialization entity for the result of a function.
- static InitializedEntity InitializeResult(SourceLocation ReturnLoc,
- QualType Type, bool NRVO) {
- return InitializedEntity(EK_Result, ReturnLoc, Type, NRVO);
+ static InitializedEntity
+ InitializeResult(SourceLocation ReturnLoc, QualType Type, bool NRVO,
+ bool GNUStatementExpression = false) {
+ return InitializedEntity(EK_Result, ReturnLoc, Type, NRVO,
+ GNUStatementExpression);
}
static InitializedEntity InitializeBlock(SourceLocation BlockVarLoc,
@@ -364,6 +371,10 @@
/// value optimization, which also applies to thrown objects.
bool allowsNRVO() const;
+ /// \brief Determine whether this initializiation is from the final
+ /// expression of GNU statement expression.
+ bool isGNUStatementExpression() const;
+
bool isParameterKind() const {
return (getKind() == EK_Parameter ||
getKind() == EK_Parameter_CF_Audited);
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