Arcoth updated this revision to Diff 97116.
Arcoth added a comment.
(Just fixed a slip after typing with the wrong window in focus...)
https://reviews.llvm.org/D32372
Files:
include/clang/Basic/DiagnosticASTKinds.td
lib/AST/ExprConstant.cpp
test/SemaCXX/constexpr-array-unknown-bound.cpp
Index: test/SemaCXX/constexpr-array-unknown-bound.cpp
===================================================================
--- /dev/null
+++ test/SemaCXX/constexpr-array-unknown-bound.cpp
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 %s -Wno-uninitialized -std=c++1z -fsyntax-only -verify
+
+const extern int arr[];
+constexpr auto p = arr; // ok
+constexpr int f(int i) {return p[i];} // expected-note {{read of dereferenced one-past-the-end pointer}}
+
+constexpr int arr[] {1, 2, 3};
+constexpr auto p2 = arr + 2; // ok
+constexpr int x = f(2); // ok
+constexpr int y = f(3); // expected-error {{constant expression}}
+// expected-note-re@-1 {{in call to 'f({{.*}})'}}
+
+struct A {int m[];} a;
+constexpr auto p3 = a.m; // ok
+constexpr auto p4 = a.m + 1; // expected-error {{constant expression}} expected-note {{constant bound}}
+
+void g(int i) {
+ int arr[i];
+ constexpr auto p = arr + 2; // expected-error {{constant expression}} expected-note {{constant bound}}
+}
Index: lib/AST/ExprConstant.cpp
===================================================================
--- lib/AST/ExprConstant.cpp
+++ lib/AST/ExprConstant.cpp
@@ -148,22 +148,26 @@
static unsigned
findMostDerivedSubobject(ASTContext &Ctx, APValue::LValueBase Base,
ArrayRef<APValue::LValuePathEntry> Path,
- uint64_t &ArraySize, QualType &Type, bool &IsArray) {
+ uint64_t &ArraySize, QualType &Type, bool &IsArray,
+ bool &isUnsizedArray) {
// This only accepts LValueBases from APValues, and APValues don't support
// arrays that lack size info.
assert(!isBaseAnAllocSizeCall(Base) &&
"Unsized arrays shouldn't appear here");
unsigned MostDerivedLength = 0;
Type = getType(Base);
for (unsigned I = 0, N = Path.size(); I != N; ++I) {
- if (Type->isArrayType()) {
- const ConstantArrayType *CAT =
- cast<ConstantArrayType>(Ctx.getAsArrayType(Type));
- Type = CAT->getElementType();
- ArraySize = CAT->getSize().getZExtValue();
+ if (auto AT = Ctx.getAsArrayType(Type)) {
MostDerivedLength = I + 1;
IsArray = true;
+ if (auto CAT = Ctx.getAsConstantArrayType(Type))
+ ArraySize = CAT->getSize().getZExtValue();
+ else {
+ ArraySize = 0;
+ isUnsizedArray = true;
+ }
+ Type = AT->getElementType();
} else if (Type->isAnyComplexType()) {
const ComplexType *CT = Type->castAs<ComplexType>();
Type = CT->getElementType();
@@ -200,8 +204,9 @@
/// Is this a pointer one past the end of an object?
unsigned IsOnePastTheEnd : 1;
- /// Indicator of whether the first entry is an unsized array.
- unsigned FirstEntryIsAnUnsizedArray : 1;
+ /// Indicator of whether the most-derived object is an unsized array (e.g.
+ /// of unknown bound).
+ unsigned MostDerivedIsAnUnsizedArray : 1;
/// Indicator of whether the most-derived object is an array element.
unsigned MostDerivedIsArrayElement : 1;
@@ -231,25 +236,28 @@
explicit SubobjectDesignator(QualType T)
: Invalid(false), IsOnePastTheEnd(false),
- FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
+ MostDerivedIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
MostDerivedPathLength(0), MostDerivedArraySize(0),
MostDerivedType(T) {}
SubobjectDesignator(ASTContext &Ctx, const APValue &V)
: Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
- FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
+ MostDerivedIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
MostDerivedPathLength(0), MostDerivedArraySize(0) {
assert(V.isLValue() && "Non-LValue used to make an LValue designator?");
if (!Invalid) {
IsOnePastTheEnd = V.isLValueOnePastTheEnd();
ArrayRef<PathEntry> VEntries = V.getLValuePath();
Entries.insert(Entries.end(), VEntries.begin(), VEntries.end());
- if (V.getLValueBase()) {
- bool IsArray = false;
+ if (auto Base = V.getLValueBase()) {
+ if (auto Decl = Base.dyn_cast<ValueDecl const*>())
+ Base = cast<ValueDecl>(Decl->getMostRecentDecl());
+ bool IsArray = false, IsUnsizedArray = false;
MostDerivedPathLength = findMostDerivedSubobject(
- Ctx, V.getLValueBase(), V.getLValuePath(), MostDerivedArraySize,
- MostDerivedType, IsArray);
- MostDerivedIsArrayElement = IsArray;
+ Ctx, Base, V.getLValuePath(), MostDerivedArraySize,
+ MostDerivedType, IsArray, IsUnsizedArray);
+ MostDerivedIsArrayElement = IsArray;
+ MostDerivedIsAnUnsizedArray = IsUnsizedArray;
}
}
}
@@ -263,7 +271,7 @@
/// known bound.
bool isMostDerivedAnUnsizedArray() const {
assert(!Invalid && "Calling this makes no sense on invalid designators");
- return Entries.size() == 1 && FirstEntryIsAnUnsizedArray;
+ return MostDerivedIsAnUnsizedArray;
}
/// Determine what the most derived array's size is. Results in an assertion
@@ -303,6 +311,7 @@
// This is a most-derived object.
MostDerivedType = CAT->getElementType();
MostDerivedIsArrayElement = true;
+ MostDerivedIsAnUnsizedArray = false;
MostDerivedArraySize = CAT->getSize().getZExtValue();
MostDerivedPathLength = Entries.size();
}
@@ -315,6 +324,7 @@
MostDerivedType = ElemTy;
MostDerivedIsArrayElement = true;
+ MostDerivedIsAnUnsizedArray = true;
// The value in MostDerivedArraySize is undefined in this case. So, set it
// to an arbitrary value that's likely to loudly break things if it's
// used.
@@ -333,6 +343,7 @@
if (const FieldDecl *FD = dyn_cast<FieldDecl>(D)) {
MostDerivedType = FD->getType();
MostDerivedIsArrayElement = false;
+ MostDerivedIsAnUnsizedArray = false;
MostDerivedArraySize = 0;
MostDerivedPathLength = Entries.size();
}
@@ -347,53 +358,14 @@
// is unlikely to matter.
MostDerivedType = EltTy;
MostDerivedIsArrayElement = true;
+ MostDerivedIsAnUnsizedArray = false;
MostDerivedArraySize = 2;
MostDerivedPathLength = Entries.size();
}
void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E,
const APSInt &N);
/// Add N to the address of this subobject.
- void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) {
- if (Invalid || !N) return;
- uint64_t TruncatedN = N.extOrTrunc(64).getZExtValue();
- if (isMostDerivedAnUnsizedArray()) {
- // Can't verify -- trust that the user is doing the right thing (or if
- // not, trust that the caller will catch the bad behavior).
- // FIXME: Should we reject if this overflows, at least?
- Entries.back().ArrayIndex += TruncatedN;
- return;
- }
-
- // [expr.add]p4: For the purposes of these operators, a pointer to a
- // nonarray object behaves the same as a pointer to the first element of
- // an array of length one with the type of the object as its element type.
- bool IsArray = MostDerivedPathLength == Entries.size() &&
- MostDerivedIsArrayElement;
- uint64_t ArrayIndex =
- IsArray ? Entries.back().ArrayIndex : (uint64_t)IsOnePastTheEnd;
- uint64_t ArraySize =
- IsArray ? getMostDerivedArraySize() : (uint64_t)1;
-
- if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) {
- // Calculate the actual index in a wide enough type, so we can include
- // it in the note.
- N = N.extend(std::max<unsigned>(N.getBitWidth() + 1, 65));
- (llvm::APInt&)N += ArrayIndex;
- assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index");
- diagnosePointerArithmetic(Info, E, N);
- setInvalid();
- return;
- }
-
- ArrayIndex += TruncatedN;
- assert(ArrayIndex <= ArraySize &&
- "bounds check succeeded for out-of-bounds index");
-
- if (IsArray)
- Entries.back().ArrayIndex = ArrayIndex;
- else
- IsOnePastTheEnd = (ArrayIndex != 0);
- }
+ void adjustIndex(EvalInfo &Info, const Expr *E, APSInt N);
};
/// A stack frame in the constexpr call stack.
@@ -495,7 +467,7 @@
// FIXME: Force the precision of the source value down so we don't
// print digits which are usually useless (we don't really care here if
// we truncate a digit by accident in edge cases). Ideally,
- // APFloat::toString would automatically print the shortest
+ // APFloat::toString would automatically print the shortest
// representation which rounds to the correct value, but it's a bit
// tricky to implement.
unsigned precision =
@@ -720,7 +692,7 @@
private:
OptionalDiagnostic Diag(SourceLocation Loc, diag::kind DiagId,
unsigned ExtraNotes, bool IsCCEDiag) {
-
+
if (EvalStatus.Diag) {
// If we have a prior diagnostic, it will be noting that the expression
// isn't a constant expression. This diagnostic is more important,
@@ -773,7 +745,7 @@
unsigned ExtraNotes = 0) {
return Diag(Loc, DiagId, ExtraNotes, false);
}
-
+
OptionalDiagnostic FFDiag(const Expr *E, diag::kind DiagId
= diag::note_invalid_subexpr_in_const_expr,
unsigned ExtraNotes = 0) {
@@ -1086,6 +1058,53 @@
setInvalid();
}
+void SubobjectDesignator::adjustIndex(EvalInfo &Info, const Expr *E, APSInt N) {
+ if (Invalid || !N) return;
+
+ uint64_t TruncatedN = N.extOrTrunc(64).getZExtValue();
+ if (isMostDerivedAnUnsizedArray()) {
+ // If we're dealing with an array without constant bound, the expression is
+ // not a constant expression.
+ if (!Info.checkingPotentialConstantExpression())
+ Info.CCEDiag(E, diag::note_constexpr_array_unknown_bound_arithmetic);
+ // Can't verify -- trust that the user is doing the right thing (or if
+ // not, trust that the caller will catch the bad behavior).
+ // FIXME: Should we reject if this overflows, at least?
+ Entries.back().ArrayIndex += TruncatedN;
+ return;
+ }
+
+ // [expr.add]p4: For the purposes of these operators, a pointer to a
+ // nonarray object behaves the same as a pointer to the first element of
+ // an array of length one with the type of the object as its element type.
+ bool IsArray = MostDerivedPathLength == Entries.size() &&
+ MostDerivedIsArrayElement;
+ uint64_t ArrayIndex =
+ IsArray ? Entries.back().ArrayIndex : (uint64_t)IsOnePastTheEnd;
+ uint64_t ArraySize =
+ IsArray ? getMostDerivedArraySize() : (uint64_t)1;
+
+ if (N < -(int64_t)ArrayIndex || N > ArraySize - ArrayIndex) {
+ // Calculate the actual index in a wide enough type, so we can include
+ // it in the note.
+ N = N.extend(std::max<unsigned>(N.getBitWidth() + 1, 65));
+ (llvm::APInt&)N += ArrayIndex;
+ assert(N.ugt(ArraySize) && "bounds check failed for in-bounds index");
+ diagnosePointerArithmetic(Info, E, N);
+ setInvalid();
+ return;
+ }
+
+ ArrayIndex += TruncatedN;
+ assert(ArrayIndex <= ArraySize &&
+ "bounds check succeeded for out-of-bounds index");
+
+ if (IsArray)
+ Entries.back().ArrayIndex = ArrayIndex;
+ else
+ IsOnePastTheEnd = (ArrayIndex != 0);
+}
+
CallStackFrame::CallStackFrame(EvalInfo &Info, SourceLocation CallLoc,
const FunctionDecl *Callee, const LValue *This,
APValue *Arguments)
@@ -1214,8 +1233,6 @@
IsNullPtr);
else {
assert(!InvalidBase && "APValues can't handle invalid LValue bases");
- assert(!Designator.FirstEntryIsAnUnsizedArray &&
- "Unsized array with a valid base?");
V = APValue(Base, Offset, Designator.Entries,
Designator.IsOnePastTheEnd, CallIndex, IsNullPtr);
}
@@ -1281,10 +1298,6 @@
Designator.addDeclUnchecked(D, Virtual);
}
void addUnsizedArray(EvalInfo &Info, QualType ElemTy) {
- assert(Designator.Entries.empty() && getType(Base)->isPointerType());
- assert(isBaseAnAllocSizeCall(Base) &&
- "Only alloc_size bases can have unsized arrays");
- Designator.FirstEntryIsAnUnsizedArray = true;
Designator.addUnsizedArrayUnchecked(ElemTy);
}
void addArray(EvalInfo &Info, const Expr *E, const ConstantArrayType *CAT) {
@@ -3016,6 +3029,15 @@
if (!evaluateVarDeclInit(Info, E, VD, Frame, BaseVal))
return CompleteObject();
+
+ // The complete object can be an array of unknown bound, in which case we
+ // have to find the most recent declaration and adjust the type accordingly.
+ if (Info.Ctx.getAsIncompleteArrayType(BaseType)) {
+ QualType MostRecentType =
+ cast<ValueDecl const>(D->getMostRecentDecl())->getType();
+ if (auto CAT = Info.Ctx.getAsConstantArrayType(MostRecentType))
+ BaseType = MostRecentType;
+ }
} else {
const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
@@ -4098,13 +4120,13 @@
if (Info.getLangOpts().CPlusPlus11) {
const FunctionDecl *DiagDecl = Definition ? Definition : Declaration;
-
+
// If this function is not constexpr because it is an inherited
// non-constexpr constructor, diagnose that directly.
auto *CD = dyn_cast<CXXConstructorDecl>(DiagDecl);
if (CD && CD->isInheritingConstructor()) {
auto *Inherited = CD->getInheritedConstructor().getConstructor();
- if (!Inherited->isConstexpr())
+ if (!Inherited->isConstexpr())
DiagDecl = CD = Inherited;
}
@@ -4635,7 +4657,7 @@
return false;
This = &ThisVal;
Args = Args.slice(1);
- } else if (MD && MD->isLambdaStaticInvoker()) {
+ } else if (MD && MD->isLambdaStaticInvoker()) {
// Map the static invoker for the lambda back to the call operator.
// Conveniently, we don't have to slice out the 'this' argument (as is
// being done for the non-static case), since a static member function
@@ -4670,7 +4692,7 @@
FD = LambdaCallOp;
}
-
+
} else
return Error(E);
@@ -5501,7 +5523,7 @@
// Update 'Result' to refer to the data member/field of the closure object
// that represents the '*this' capture.
if (!HandleLValueMember(Info, E, Result,
- Info.CurrentCall->LambdaThisCaptureField))
+ Info.CurrentCall->LambdaThisCaptureField))
return false;
// If we captured '*this' by reference, replace the field with its referent.
if (Info.CurrentCall->LambdaThisCaptureField->getType()
@@ -5642,12 +5664,18 @@
Info, Result, SubExpr))
return false;
}
+
// The result is a pointer to the first element of the array.
if (const ConstantArrayType *CAT
= Info.Ctx.getAsConstantArrayType(SubExpr->getType()))
Result.addArray(Info, E, CAT);
- else
- Result.Designator.setInvalid();
+ // If the array hasn't been given a bound yet, add it as an unsized one.
+ else {
+ auto AT = Info.Ctx.getAsArrayType(SubExpr->getType());
+ assert(AT && "Array to pointer decay on non-array object?");
+ Result.addUnsizedArray(Info, AT->getElementType());
+ }
+
return true;
case CK_FunctionToPointerDecay:
@@ -6345,7 +6373,7 @@
if (ClosureClass->isInvalidDecl()) return false;
if (Info.checkingPotentialConstantExpression()) return true;
-
+
const size_t NumFields =
std::distance(ClosureClass->field_begin(), ClosureClass->field_end());
@@ -6364,7 +6392,7 @@
assert(CaptureInitIt != E->capture_init_end());
// Get the initializer for this field
Expr *const CurFieldInit = *CaptureInitIt++;
-
+
// If there is no initializer, either this is a VLA or an error has
// occurred.
if (!CurFieldInit)
@@ -6565,18 +6593,18 @@
// The number of initializers can be less than the number of
// vector elements. For OpenCL, this can be due to nested vector
- // initialization. For GCC compatibility, missing trailing elements
+ // initialization. For GCC compatibility, missing trailing elements
// should be initialized with zeroes.
unsigned CountInits = 0, CountElts = 0;
while (CountElts < NumElements) {
// Handle nested vector initialization.
- if (CountInits < NumInits
+ if (CountInits < NumInits
&& E->getInit(CountInits)->getType()->isVectorType()) {
APValue v;
if (!EvaluateVector(E->getInit(CountInits), v, Info))
return Error(E);
unsigned vlen = v.getVectorLength();
- for (unsigned j = 0; j < vlen; j++)
+ for (unsigned j = 0; j < vlen; j++)
Elements.push_back(v.getVectorElt(j));
CountElts += vlen;
} else if (EltTy->isIntegerType()) {
@@ -6852,7 +6880,7 @@
}
bool Success(const llvm::APInt &I, const Expr *E, APValue &Result) {
- assert(E->getType()->isIntegralOrEnumerationType() &&
+ assert(E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.");
assert(I.getBitWidth() == Info.Ctx.getIntWidth(E->getType()) &&
"Invalid evaluation result.");
@@ -6866,7 +6894,7 @@
}
bool Success(uint64_t Value, const Expr *E, APValue &Result) {
- assert(E->getType()->isIntegralOrEnumerationType() &&
+ assert(E->getType()->isIntegralOrEnumerationType() &&
"Invalid evaluation result.");
Result = APValue(Info.Ctx.MakeIntValue(Value, E->getType()));
return true;
@@ -6942,7 +6970,7 @@
}
return Success(Info.ArrayInitIndex, E);
}
-
+
// Note, GNU defines __null as an integer, not a pointer.
bool VisitGNUNullExpr(const GNUNullExpr *E) {
return ZeroInitialization(E);
@@ -7306,10 +7334,8 @@
unsigned I = 0;
QualType BaseType = getType(Base);
- if (LVal.Designator.FirstEntryIsAnUnsizedArray) {
- assert(isBaseAnAllocSizeCall(Base) &&
- "Unsized array in non-alloc_size call?");
- // If this is an alloc_size base, we should ignore the initial array index
+ // If this is an alloc_size base, we should ignore the initial array index
+ if (isBaseAnAllocSizeCall(Base)) {
++I;
BaseType = BaseType->castAs<PointerType>()->getPointeeType();
}
@@ -8096,12 +8122,12 @@
Result = RHSResult.Val;
return true;
}
-
+
if (E->isLogicalOp()) {
bool lhsResult, rhsResult;
bool LHSIsOK = HandleConversionToBool(LHSResult.Val, lhsResult);
bool RHSIsOK = HandleConversionToBool(RHSResult.Val, rhsResult);
-
+
if (LHSIsOK) {
if (RHSIsOK) {
if (E->getOpcode() == BO_LOr)
@@ -8117,34 +8143,34 @@
return Success(rhsResult, E, Result);
}
}
-
+
return false;
}
-
+
assert(E->getLHS()->getType()->isIntegralOrEnumerationType() &&
E->getRHS()->getType()->isIntegralOrEnumerationType());
-
+
if (LHSResult.Failed || RHSResult.Failed)
return false;
-
+
const APValue &LHSVal = LHSResult.Val;
const APValue &RHSVal = RHSResult.Val;
-
+
// Handle cases like (unsigned long)&a + 4.
if (E->isAdditiveOp() && LHSVal.isLValue() && RHSVal.isInt()) {
Result = LHSVal;
addOrSubLValueAsInteger(Result, RHSVal.getInt(), E->getOpcode() == BO_Sub);
return true;
}
-
+
// Handle cases like 4 + (unsigned long)&a
if (E->getOpcode() == BO_Add &&
RHSVal.isLValue() && LHSVal.isInt()) {
Result = RHSVal;
addOrSubLValueAsInteger(Result, LHSVal.getInt(), /*IsSub*/false);
return true;
}
-
+
if (E->getOpcode() == BO_Sub && LHSVal.isLValue() && RHSVal.isLValue()) {
// Handle (intptr_t)&&A - (intptr_t)&&B.
if (!LHSVal.getLValueOffset().isZero() ||
@@ -8183,7 +8209,7 @@
void DataRecursiveIntBinOpEvaluator::process(EvalResult &Result) {
Job &job = Queue.back();
-
+
switch (job.Kind) {
case Job::AnyExprKind: {
if (const BinaryOperator *Bop = dyn_cast<BinaryOperator>(job.E)) {
@@ -8193,12 +8219,12 @@
return;
}
}
-
+
EvaluateExpr(job.E, Result);
Queue.pop_back();
return;
}
-
+
case Job::BinOpKind: {
const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
bool SuppressRHSDiags = false;
@@ -8213,7 +8239,7 @@
enqueue(Bop->getRHS());
return;
}
-
+
case Job::BinOpVisitedLHSKind: {
const BinaryOperator *Bop = cast<BinaryOperator>(job.E);
EvalResult RHS;
@@ -8223,7 +8249,7 @@
return;
}
}
-
+
llvm_unreachable("Invalid Job::Kind!");
}
@@ -8735,7 +8761,7 @@
const RecordType *BaseRT = CurrentType->getAs<RecordType>();
if (!BaseRT)
return Error(OOE);
-
+
// Add the offset to the base.
Result += RL.getBaseClassOffset(cast<CXXRecordDecl>(BaseRT->getDecl()));
break;
@@ -9929,7 +9955,7 @@
IsConst = false;
return true;
}
-
+
// FIXME: Evaluating values of large array and record types can cause
// performance problems. Only do so in C++11 for now.
if (Exp->isRValue() && (Exp->getType()->isArrayType() ||
@@ -9951,7 +9977,7 @@
bool IsConst;
if (FastEvaluateAsRValue(this, Result, Ctx, IsConst))
return IsConst;
-
+
EvalInfo Info(Ctx, Result, EvalInfo::EM_IgnoreSideEffects);
return ::EvaluateAsRValue(Info, this, Result.Val);
}
Index: include/clang/Basic/DiagnosticASTKinds.td
===================================================================
--- include/clang/Basic/DiagnosticASTKinds.td
+++ include/clang/Basic/DiagnosticASTKinds.td
@@ -154,12 +154,14 @@
def note_constexpr_baa_value_insufficient_alignment : Note<
"value of the aligned pointer (%0) is not a multiple of the asserted %1 "
"%plural{1:byte|:bytes}1">;
+def note_constexpr_array_unknown_bound_arithmetic : Note<
+ "cannot perform pointer arithmetic on pointer to array without constant bound">;
def warn_integer_constant_overflow : Warning<
"overflow in expression; result is %0 with type %1">,
InGroup<DiagGroup<"integer-overflow">>;
-// This is a temporary diagnostic, and shall be removed once our
+// This is a temporary diagnostic, and shall be removed once our
// implementation is complete, and like the preceding constexpr notes belongs
// in Sema.
def note_unimplemented_constexpr_lambda_feature_ast : Note<
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
