Refactor: split Uninitialized state on APValue into an "Absent" state
representing no such object, and an "Indeterminate" state representing
an uninitialized object. The latter is not yet used, but soon will be.
llvm-svn: 361328
diff --git a/clang/include/clang/AST/APValue.h b/clang/include/clang/AST/APValue.h
index 15f8944..02a6394 100644
--- a/clang/include/clang/AST/APValue.h
+++ b/clang/include/clang/AST/APValue.h
@@ -78,7 +78,10 @@
typedef llvm::APFloat APFloat;
public:
enum ValueKind {
- Uninitialized,
+ /// There is no such object (it's outside its lifetime).
+ None,
+ /// This object has an indeterminate value (C++ [basic.indet]).
+ Indeterminate,
Int,
Float,
FixedPoint,
@@ -231,58 +234,59 @@
DataType Data;
public:
- APValue() : Kind(Uninitialized) {}
- explicit APValue(APSInt I) : Kind(Uninitialized) {
+ APValue() : Kind(None) {}
+ explicit APValue(APSInt I) : Kind(None) {
MakeInt(); setInt(std::move(I));
}
- explicit APValue(APFloat F) : Kind(Uninitialized) {
+ explicit APValue(APFloat F) : Kind(None) {
MakeFloat(); setFloat(std::move(F));
}
- explicit APValue(APFixedPoint FX) : Kind(Uninitialized) {
+ explicit APValue(APFixedPoint FX) : Kind(None) {
MakeFixedPoint(std::move(FX));
}
- explicit APValue(const APValue *E, unsigned N) : Kind(Uninitialized) {
+ explicit APValue(const APValue *E, unsigned N) : Kind(None) {
MakeVector(); setVector(E, N);
}
- APValue(APSInt R, APSInt I) : Kind(Uninitialized) {
+ APValue(APSInt R, APSInt I) : Kind(None) {
MakeComplexInt(); setComplexInt(std::move(R), std::move(I));
}
- APValue(APFloat R, APFloat I) : Kind(Uninitialized) {
+ APValue(APFloat R, APFloat I) : Kind(None) {
MakeComplexFloat(); setComplexFloat(std::move(R), std::move(I));
}
APValue(const APValue &RHS);
- APValue(APValue &&RHS) : Kind(Uninitialized) { swap(RHS); }
+ APValue(APValue &&RHS) : Kind(None) { swap(RHS); }
APValue(LValueBase B, const CharUnits &O, NoLValuePath N,
bool IsNullPtr = false)
- : Kind(Uninitialized) {
+ : Kind(None) {
MakeLValue(); setLValue(B, O, N, IsNullPtr);
}
APValue(LValueBase B, const CharUnits &O, ArrayRef<LValuePathEntry> Path,
bool OnePastTheEnd, bool IsNullPtr = false)
- : Kind(Uninitialized) {
+ : Kind(None) {
MakeLValue(); setLValue(B, O, Path, OnePastTheEnd, IsNullPtr);
}
- APValue(UninitArray, unsigned InitElts, unsigned Size) : Kind(Uninitialized) {
+ APValue(UninitArray, unsigned InitElts, unsigned Size) : Kind(None) {
MakeArray(InitElts, Size);
}
- APValue(UninitStruct, unsigned B, unsigned M) : Kind(Uninitialized) {
+ APValue(UninitStruct, unsigned B, unsigned M) : Kind(None) {
MakeStruct(B, M);
}
explicit APValue(const FieldDecl *D, const APValue &V = APValue())
- : Kind(Uninitialized) {
+ : Kind(None) {
MakeUnion(); setUnion(D, V);
}
APValue(const ValueDecl *Member, bool IsDerivedMember,
- ArrayRef<const CXXRecordDecl*> Path) : Kind(Uninitialized) {
+ ArrayRef<const CXXRecordDecl*> Path) : Kind(None) {
MakeMemberPointer(Member, IsDerivedMember, Path);
}
APValue(const AddrLabelExpr* LHSExpr, const AddrLabelExpr* RHSExpr)
- : Kind(Uninitialized) {
+ : Kind(None) {
MakeAddrLabelDiff(); setAddrLabelDiff(LHSExpr, RHSExpr);
}
~APValue() {
- MakeUninit();
+ if (Kind != None && Kind != Indeterminate)
+ DestroyDataAndMakeUninit();
}
/// Returns whether the object performed allocations.
@@ -296,7 +300,11 @@
void swap(APValue &RHS);
ValueKind getKind() const { return Kind; }
- bool isUninit() const { return Kind == Uninitialized; }
+
+ bool isAbsent() const { return Kind == None; }
+ bool isIndeterminate() const { return Kind == Indeterminate; }
+ bool hasValue() const { return Kind != None && Kind != Indeterminate; }
+
bool isInt() const { return Kind == Int; }
bool isFloat() const { return Kind == Float; }
bool isFixedPoint() const { return Kind == FixedPoint; }
@@ -536,56 +544,52 @@
private:
void DestroyDataAndMakeUninit();
- void MakeUninit() {
- if (Kind != Uninitialized)
- DestroyDataAndMakeUninit();
- }
void MakeInt() {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
new ((void*)Data.buffer) APSInt(1);
Kind = Int;
}
void MakeFloat() {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
new ((void*)(char*)Data.buffer) APFloat(0.0);
Kind = Float;
}
void MakeFixedPoint(APFixedPoint &&FX) {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
new ((void *)(char *)Data.buffer) APFixedPoint(std::move(FX));
Kind = FixedPoint;
}
void MakeVector() {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
new ((void*)(char*)Data.buffer) Vec();
Kind = Vector;
}
void MakeComplexInt() {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
new ((void*)(char*)Data.buffer) ComplexAPSInt();
Kind = ComplexInt;
}
void MakeComplexFloat() {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
new ((void*)(char*)Data.buffer) ComplexAPFloat();
Kind = ComplexFloat;
}
void MakeLValue();
void MakeArray(unsigned InitElts, unsigned Size);
void MakeStruct(unsigned B, unsigned M) {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
new ((void*)(char*)Data.buffer) StructData(B, M);
Kind = Struct;
}
void MakeUnion() {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
new ((void*)(char*)Data.buffer) UnionData();
Kind = Union;
}
void MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
ArrayRef<const CXXRecordDecl*> Path);
void MakeAddrLabelDiff() {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
new ((void*)(char*)Data.buffer) AddrLabelDiffData();
Kind = AddrLabelDiff;
}
diff --git a/clang/include/clang/Basic/DiagnosticASTKinds.td b/clang/include/clang/Basic/DiagnosticASTKinds.td
index a9e88d5..f1172a9 100644
--- a/clang/include/clang/Basic/DiagnosticASTKinds.td
+++ b/clang/include/clang/Basic/DiagnosticASTKinds.td
@@ -115,7 +115,8 @@
def note_constexpr_access_uninit : Note<
"%select{read of|assignment to|increment of|decrement of|member call on|"
"dynamic_cast of|typeid applied to}0 "
- "object outside its lifetime is not allowed in a constant expression">;
+ "%select{object outside its lifetime|uninitialized object}1 "
+ "is not allowed in a constant expression">;
def note_constexpr_use_uninit_reference : Note<
"use of reference outside its lifetime "
"is not allowed in a constant expression">;
diff --git a/clang/lib/AST/APValue.cpp b/clang/lib/AST/APValue.cpp
index c5db3cd..5d5e67a 100644
--- a/clang/lib/AST/APValue.cpp
+++ b/clang/lib/AST/APValue.cpp
@@ -219,9 +219,11 @@
delete Value;
}
-APValue::APValue(const APValue &RHS) : Kind(Uninitialized) {
+APValue::APValue(const APValue &RHS) : Kind(None) {
switch (RHS.getKind()) {
- case Uninitialized:
+ case None:
+ case Indeterminate:
+ Kind = RHS.getKind();
break;
case Int:
MakeInt();
@@ -313,12 +315,13 @@
((MemberPointerData*)(char*)Data.buffer)->~MemberPointerData();
else if (Kind == AddrLabelDiff)
((AddrLabelDiffData*)(char*)Data.buffer)->~AddrLabelDiffData();
- Kind = Uninitialized;
+ Kind = None;
}
bool APValue::needsCleanup() const {
switch (getKind()) {
- case Uninitialized:
+ case None:
+ case Indeterminate:
case AddrLabelDiff:
return false;
case Struct:
@@ -376,8 +379,11 @@
void APValue::dump(raw_ostream &OS) const {
switch (getKind()) {
- case Uninitialized:
- OS << "Uninitialized";
+ case None:
+ OS << "None";
+ return;
+ case Indeterminate:
+ OS << "Indeterminate";
return;
case Int:
OS << "Int: " << getInt();
@@ -452,7 +458,10 @@
void APValue::printPretty(raw_ostream &Out, ASTContext &Ctx, QualType Ty) const{
switch (getKind()) {
- case APValue::Uninitialized:
+ case APValue::None:
+ Out << "<out of lifetime>";
+ return;
+ case APValue::Indeterminate:
Out << "<uninitialized>";
return;
case APValue::Int:
@@ -781,21 +790,21 @@
}
void APValue::MakeLValue() {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
static_assert(sizeof(LV) <= DataSize, "LV too big");
new ((void*)(char*)Data.buffer) LV();
Kind = LValue;
}
void APValue::MakeArray(unsigned InitElts, unsigned Size) {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
new ((void*)(char*)Data.buffer) Arr(InitElts, Size);
Kind = Array;
}
void APValue::MakeMemberPointer(const ValueDecl *Member, bool IsDerivedMember,
ArrayRef<const CXXRecordDecl*> Path) {
- assert(isUninit() && "Bad state change");
+ assert(isAbsent() && "Bad state change");
MemberPointerData *MPD = new ((void*)(char*)Data.buffer) MemberPointerData;
Kind = MemberPointer;
MPD->MemberAndIsDerivedMember.setPointer(Member);
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index bc0a5a4..8b77e01 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -2302,7 +2302,7 @@
// first time it is evaluated. FIXME: The notes won't always be emitted the
// first time we try evaluation, so might not be produced at all.
if (Eval->WasEvaluated)
- return Eval->Evaluated.isUninit() ? nullptr : &Eval->Evaluated;
+ return Eval->Evaluated.isAbsent() ? nullptr : &Eval->Evaluated;
const auto *Init = cast<Expr>(Eval->Value);
assert(!Init->isValueDependent());
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index e654480..5084564 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1291,7 +1291,7 @@
bool IsLifetimeExtended) {
unsigned Version = Info.CurrentCall->getTempVersion();
APValue &Result = Temporaries[MapKeyTy(Key, Version)];
- assert(Result.isUninit() && "temporary created multiple times");
+ assert(Result.isAbsent() && "temporary created multiple times");
Info.CleanupStack.push_back(Cleanup(&Result, IsLifetimeExtended));
return Result;
}
@@ -2025,7 +2025,7 @@
CheckConstantExpression(EvalInfo &Info, SourceLocation DiagLoc, QualType Type,
const APValue &Value,
Expr::ConstExprUsage Usage = Expr::EvaluateForCodeGen) {
- if (Value.isUninit()) {
+ if (!Value.hasValue()) {
Info.FFDiag(DiagLoc, diag::note_constexpr_uninitialized)
<< true << Type;
return false;
@@ -2108,7 +2108,8 @@
static bool HandleConversionToBool(const APValue &Val, bool &Result) {
switch (Val.getKind()) {
- case APValue::Uninitialized:
+ case APValue::None:
+ case APValue::Indeterminate:
return false;
case APValue::Int:
Result = Val.getInt().getBoolValue();
@@ -2971,10 +2972,10 @@
// Walk the designator's path to find the subobject.
for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
- if (O->isUninit()) {
+ if (!O->hasValue()) {
if (!Info.checkingPotentialConstantExpression())
Info.FFDiag(E, diag::note_constexpr_access_uninit)
- << handler.AccessKind;
+ << handler.AccessKind << O->isIndeterminate();
return handler.failed();
}
@@ -5040,7 +5041,7 @@
}
// Reserve space for the struct members.
- if (!RD->isUnion() && Result.isUninit())
+ if (!RD->isUnion() && !Result.hasValue())
Result = APValue(APValue::UninitStruct(), RD->getNumBases(),
std::distance(RD->field_begin(), RD->field_end()));
@@ -5097,7 +5098,7 @@
// subobject other than the first.
// FIXME: In this case, the values of the other subobjects are
// specified, since zero-initialization sets all padding bits to zero.
- if (Value->isUninit() ||
+ if (!Value->hasValue() ||
(Value->isUnion() && Value->getUnionField() != FD)) {
if (CD->isUnion())
*Value = APValue(FD);
@@ -5953,7 +5954,9 @@
APValue *V;
if (!evaluateVarDeclInit(Info, E, VD, Frame, V, nullptr))
return false;
- if (V->isUninit()) {
+ if (!V->hasValue()) {
+ // FIXME: Is it possible for V to be indeterminate here? If so, we should
+ // adjust the diagnostic to say that.
if (!Info.checkingPotentialConstantExpression())
Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
return false;
@@ -7217,7 +7220,7 @@
return EvaluateInPlace(Result.getUnionValue(), Info, Subobject, InitExpr);
}
- if (Result.isUninit())
+ if (!Result.hasValue())
Result = APValue(APValue::UninitStruct(), CXXRD ? CXXRD->getNumBases() : 0,
std::distance(RD->field_begin(), RD->field_end()));
unsigned ElementNo = 0;
@@ -7294,7 +7297,7 @@
bool ZeroInit = E->requiresZeroInitialization();
if (CheckTrivialDefaultConstructor(Info, E->getExprLoc(), FD, ZeroInit)) {
// If we've already performed zero-initialization, we're already done.
- if (!Result.isUninit())
+ if (Result.hasValue())
return true;
// We can get here in two different ways:
@@ -7794,7 +7797,7 @@
// If the array was previously zero-initialized, preserve the
// zero-initialized values.
- if (!Filler.isUninit()) {
+ if (Filler.hasValue()) {
for (unsigned I = 0, E = Result.getArrayInitializedElts(); I != E; ++I)
Result.getArrayInitializedElt(I) = Filler;
if (Result.hasArrayFiller())
@@ -7863,7 +7866,7 @@
const LValue &Subobject,
APValue *Value,
QualType Type) {
- bool HadZeroInit = !Value->isUninit();
+ bool HadZeroInit = Value->hasValue();
if (const ConstantArrayType *CAT = Info.Ctx.getAsConstantArrayType(Type)) {
unsigned N = CAT->getSize().getZExtValue();
@@ -8427,7 +8430,7 @@
return EvaluateBuiltinConstantPForLValue(V);
// Otherwise, any constant value is good enough.
- return V.getKind() != APValue::Uninitialized;
+ return V.hasValue();
}
// Anything else isn't considered to be sufficiently constant.
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 70904b1..caa327c 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -1860,8 +1860,10 @@
llvm::Constant *ConstantEmitter::tryEmitPrivate(const APValue &Value,
QualType DestType) {
switch (Value.getKind()) {
- case APValue::Uninitialized:
- llvm_unreachable("Constant expressions should be initialized.");
+ case APValue::None:
+ case APValue::Indeterminate:
+ // Out-of-lifetime and indeterminate values can be modeled as 'undef'.
+ return llvm::UndefValue::get(CGM.getTypes().ConvertType(DestType));
case APValue::LValue:
return ConstantLValueEmitter(*this, Value, DestType).tryEmit();
case APValue::Int:
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index a2d6d59..b9573f7 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -1990,7 +1990,7 @@
void CodeGenFunction::EmitDeclRefExprDbgValue(const DeclRefExpr *E,
const APValue &Init) {
- assert(!Init.isUninit() && "Invalid DeclRefExpr initializer!");
+ assert(Init.hasValue() && "Invalid DeclRefExpr initializer!");
if (CGDebugInfo *Dbg = getDebugInfo())
if (CGM.getCodeGenOpts().getDebugInfo() >= codegenoptions::LimitedDebugInfo)
Dbg->EmitGlobalVariable(E->getDecl(), Init);
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index a16e7ce..6daea41 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -4886,7 +4886,7 @@
// evaluating the initializer if the surrounding constant expression
// modifies the temporary.
Value = getContext().getMaterializedTemporaryValue(E, false);
- if (Value && Value->isUninit())
+ if (Value && Value->isAbsent())
Value = nullptr;
}
diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp
index 239b4ae..2483a28 100644
--- a/clang/lib/Sema/SemaTemplate.cpp
+++ b/clang/lib/Sema/SemaTemplate.cpp
@@ -6390,10 +6390,13 @@
// Convert the APValue to a TemplateArgument.
switch (Value.getKind()) {
- case APValue::Uninitialized:
+ case APValue::None:
assert(ParamType->isNullPtrType());
Converted = TemplateArgument(CanonParamType, /*isNullPtr*/true);
break;
+ case APValue::Indeterminate:
+ llvm_unreachable("result of constant evaluation should be initialized");
+ break;
case APValue::Int:
assert(ParamType->isIntegralOrEnumerationType());
Converted = TemplateArgument(Context, Value.getInt(), CanonParamType);