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-rw-r--r--lib/Sema/SemaChecking.cpp406
1 files changed, 273 insertions, 133 deletions
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 7029711..4f3f41b 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -75,14 +75,15 @@ SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
TheLexer.LexFromRawLexer(TheTok);
// Use the StringLiteralParser to compute the length of the string in bytes.
- StringLiteralParser SLP(&TheTok, 1, PP);
+ StringLiteralParser SLP(&TheTok, 1, PP, /*Complain=*/false);
unsigned TokNumBytes = SLP.GetStringLength();
// If the byte is in this token, return the location of the byte.
if (ByteNo < TokNumBytes ||
(ByteNo == TokNumBytes && TokNo == SL->getNumConcatenated())) {
unsigned Offset =
- StringLiteralParser::getOffsetOfStringByte(TheTok, ByteNo, PP);
+ StringLiteralParser::getOffsetOfStringByte(TheTok, ByteNo, PP,
+ /*Complain=*/false);
// Now that we know the offset of the token in the spelling, use the
// preprocessor to get the offset in the original source.
@@ -607,12 +608,25 @@ bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
if (OrigArg->isTypeDependent())
return false;
- // This operation requires a floating-point number
+ // This operation requires a non-_Complex floating-point number.
if (!OrigArg->getType()->isRealFloatingType())
return Diag(OrigArg->getLocStart(),
diag::err_typecheck_call_invalid_unary_fp)
<< OrigArg->getType() << OrigArg->getSourceRange();
+ // If this is an implicit conversion from float -> double, remove it.
+ if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
+ Expr *CastArg = Cast->getSubExpr();
+ if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
+ assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
+ "promotion from float to double is the only expected cast here");
+ Cast->setSubExpr(0);
+ Cast->Destroy(Context);
+ TheCall->setArg(NumArgs-1, CastArg);
+ OrigArg = CastArg;
+ }
+ }
+
return false;
}
@@ -1718,8 +1732,14 @@ struct IntRange {
T = VT->getElementType().getTypePtr();
if (const ComplexType *CT = dyn_cast<ComplexType>(T))
T = CT->getElementType().getTypePtr();
- if (const EnumType *ET = dyn_cast<EnumType>(T))
- T = ET->getDecl()->getIntegerType().getTypePtr();
+
+ if (const EnumType *ET = dyn_cast<EnumType>(T)) {
+ EnumDecl *Enum = ET->getDecl();
+ unsigned NumPositive = Enum->getNumPositiveBits();
+ unsigned NumNegative = Enum->getNumNegativeBits();
+
+ return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0);
+ }
const BuiltinType *BT = cast<BuiltinType>(T);
assert(BT->isInteger());
@@ -1961,6 +1981,10 @@ IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
return IntRange::forType(C, E->getType());
}
+IntRange GetExprRange(ASTContext &C, Expr *E) {
+ return GetExprRange(C, E, C.getIntWidth(E->getType()));
+}
+
/// Checks whether the given value, which currently has the given
/// source semantics, has the same value when coerced through the
/// target semantics.
@@ -1999,7 +2023,40 @@ bool IsSameFloatAfterCast(const APValue &value,
IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
}
-} // end anonymous namespace
+void AnalyzeImplicitConversions(Sema &S, Expr *E);
+
+bool IsZero(Sema &S, Expr *E) {
+ llvm::APSInt Value;
+ return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
+}
+
+void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
+ BinaryOperator::Opcode op = E->getOpcode();
+ if (op == BinaryOperator::LT && IsZero(S, E->getRHS())) {
+ S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
+ << "< 0" << "false"
+ << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
+ } else if (op == BinaryOperator::GE && IsZero(S, E->getRHS())) {
+ S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
+ << ">= 0" << "true"
+ << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
+ } else if (op == BinaryOperator::GT && IsZero(S, E->getLHS())) {
+ S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
+ << "0 >" << "false"
+ << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
+ } else if (op == BinaryOperator::LE && IsZero(S, E->getLHS())) {
+ S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
+ << "0 <=" << "true"
+ << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
+ }
+}
+
+/// Analyze the operands of the given comparison. Implements the
+/// fallback case from AnalyzeComparison.
+void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
+ AnalyzeImplicitConversions(S, E->getLHS());
+ AnalyzeImplicitConversions(S, E->getRHS());
+}
/// \brief Implements -Wsign-compare.
///
@@ -2007,138 +2064,85 @@ bool IsSameFloatAfterCast(const APValue &value,
/// \param rex the right-hand expression
/// \param OpLoc the location of the joining operator
/// \param BinOpc binary opcode or 0
-void Sema::CheckSignCompare(Expr *lex, Expr *rex, SourceLocation OpLoc,
- const BinaryOperator::Opcode* BinOpc) {
- // Don't warn if we're in an unevaluated context.
- if (ExprEvalContexts.back().Context == Unevaluated)
- return;
-
- // If either expression is value-dependent, don't warn. We'll get another
- // chance at instantiation time.
- if (lex->isValueDependent() || rex->isValueDependent())
- return;
-
- QualType lt = lex->getType(), rt = rex->getType();
-
- // Only warn if both operands are integral.
- if (!lt->isIntegerType() || !rt->isIntegerType())
- return;
-
- // In C, the width of a bitfield determines its type, and the
- // declared type only contributes the signedness. This duplicates
- // the work that will later be done by UsualUnaryConversions.
- // Eventually, this check will be reorganized in a way that avoids
- // this duplication.
- if (!getLangOptions().CPlusPlus) {
- QualType tmp;
- tmp = Context.isPromotableBitField(lex);
- if (!tmp.isNull()) lt = tmp;
- tmp = Context.isPromotableBitField(rex);
- if (!tmp.isNull()) rt = tmp;
- }
-
- if (const EnumType *E = lt->getAs<EnumType>())
- lt = E->getDecl()->getPromotionType();
- if (const EnumType *E = rt->getAs<EnumType>())
- rt = E->getDecl()->getPromotionType();
-
- // The rule is that the signed operand becomes unsigned, so isolate the
- // signed operand.
- Expr *signedOperand = lex, *unsignedOperand = rex;
- QualType signedType = lt, unsignedType = rt;
- if (lt->isSignedIntegerType()) {
- if (rt->isSignedIntegerType()) return;
+void AnalyzeComparison(Sema &S, BinaryOperator *E) {
+ // The type the comparison is being performed in.
+ QualType T = E->getLHS()->getType();
+ assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())
+ && "comparison with mismatched types");
+
+ // We don't do anything special if this isn't an unsigned integral
+ // comparison: we're only interested in integral comparisons, and
+ // signed comparisons only happen in cases we don't care to warn about.
+ if (!T->isUnsignedIntegerType())
+ return AnalyzeImpConvsInComparison(S, E);
+
+ Expr *lex = E->getLHS()->IgnoreParenImpCasts();
+ Expr *rex = E->getRHS()->IgnoreParenImpCasts();
+
+ // Check to see if one of the (unmodified) operands is of different
+ // signedness.
+ Expr *signedOperand, *unsignedOperand;
+ if (lex->getType()->isSignedIntegerType()) {
+ assert(!rex->getType()->isSignedIntegerType() &&
+ "unsigned comparison between two signed integer expressions?");
+ signedOperand = lex;
+ unsignedOperand = rex;
+ } else if (rex->getType()->isSignedIntegerType()) {
+ signedOperand = rex;
+ unsignedOperand = lex;
} else {
- if (!rt->isSignedIntegerType()) return;
- std::swap(signedOperand, unsignedOperand);
- std::swap(signedType, unsignedType);
+ CheckTrivialUnsignedComparison(S, E);
+ return AnalyzeImpConvsInComparison(S, E);
}
- unsigned unsignedWidth = Context.getIntWidth(unsignedType);
- unsigned signedWidth = Context.getIntWidth(signedType);
+ // Otherwise, calculate the effective range of the signed operand.
+ IntRange signedRange = GetExprRange(S.Context, signedOperand);
- // If the unsigned type is strictly smaller than the signed type,
- // then (1) the result type will be signed and (2) the unsigned
- // value will fit fully within the signed type, and thus the result
- // of the comparison will be exact.
- if (signedWidth > unsignedWidth)
- return;
+ // Go ahead and analyze implicit conversions in the operands. Note
+ // that we skip the implicit conversions on both sides.
+ AnalyzeImplicitConversions(S, lex);
+ AnalyzeImplicitConversions(S, rex);
- // Otherwise, calculate the effective ranges.
- IntRange signedRange = GetExprRange(Context, signedOperand, signedWidth);
- IntRange unsignedRange = GetExprRange(Context, unsignedOperand, unsignedWidth);
-
- // We should never be unable to prove that the unsigned operand is
- // non-negative.
- assert(unsignedRange.NonNegative && "unsigned range includes negative?");
-
- // If the signed operand is non-negative, then the signed->unsigned
- // conversion won't change it.
- if (signedRange.NonNegative) {
- // Emit warnings for comparisons of unsigned to integer constant 0.
- // always false: x < 0 (or 0 > x)
- // always true: x >= 0 (or 0 <= x)
- llvm::APSInt X;
- if (BinOpc && signedOperand->isIntegerConstantExpr(X, Context) && X == 0) {
- if (signedOperand != lex) {
- if (*BinOpc == BinaryOperator::LT) {
- Diag(OpLoc, diag::warn_lunsigned_always_true_comparison)
- << "< 0" << "false"
- << lex->getSourceRange() << rex->getSourceRange();
- }
- else if (*BinOpc == BinaryOperator::GE) {
- Diag(OpLoc, diag::warn_lunsigned_always_true_comparison)
- << ">= 0" << "true"
- << lex->getSourceRange() << rex->getSourceRange();
- }
- }
- else {
- if (*BinOpc == BinaryOperator::GT) {
- Diag(OpLoc, diag::warn_runsigned_always_true_comparison)
- << "0 >" << "false"
- << lex->getSourceRange() << rex->getSourceRange();
- }
- else if (*BinOpc == BinaryOperator::LE) {
- Diag(OpLoc, diag::warn_runsigned_always_true_comparison)
- << "0 <=" << "true"
- << lex->getSourceRange() << rex->getSourceRange();
- }
- }
- }
- return;
- }
+ // If the signed range is non-negative, -Wsign-compare won't fire,
+ // but we should still check for comparisons which are always true
+ // or false.
+ if (signedRange.NonNegative)
+ return CheckTrivialUnsignedComparison(S, E);
// For (in)equality comparisons, if the unsigned operand is a
// constant which cannot collide with a overflowed signed operand,
// then reinterpreting the signed operand as unsigned will not
// change the result of the comparison.
- if (BinOpc &&
- (*BinOpc == BinaryOperator::EQ || *BinOpc == BinaryOperator::NE) &&
- unsignedRange.Width < unsignedWidth)
- return;
+ if (E->isEqualityOp()) {
+ unsigned comparisonWidth = S.Context.getIntWidth(T);
+ IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
+
+ // We should never be unable to prove that the unsigned operand is
+ // non-negative.
+ assert(unsignedRange.NonNegative && "unsigned range includes negative?");
+
+ if (unsignedRange.Width < comparisonWidth)
+ return;
+ }
- Diag(OpLoc, BinOpc ? diag::warn_mixed_sign_comparison
- : diag::warn_mixed_sign_conditional)
- << lt << rt << lex->getSourceRange() << rex->getSourceRange();
+ S.Diag(E->getOperatorLoc(), diag::warn_mixed_sign_comparison)
+ << lex->getType() << rex->getType()
+ << lex->getSourceRange() << rex->getSourceRange();
}
/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion.
-static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, unsigned diag) {
+void DiagnoseImpCast(Sema &S, Expr *E, QualType T, unsigned diag) {
S.Diag(E->getExprLoc(), diag) << E->getType() << T << E->getSourceRange();
}
-/// Implements -Wconversion.
-void Sema::CheckImplicitConversion(Expr *E, QualType T) {
- // Don't diagnose in unevaluated contexts.
- if (ExprEvalContexts.back().Context == Sema::Unevaluated)
- return;
+void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
+ bool *ICContext = 0) {
+ if (E->isTypeDependent() || E->isValueDependent()) return;
- // Don't diagnose for value-dependent expressions.
- if (E->isValueDependent())
- return;
-
- const Type *Source = Context.getCanonicalType(E->getType()).getTypePtr();
- const Type *Target = Context.getCanonicalType(T).getTypePtr();
+ const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
+ const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
+ if (Source == Target) return;
+ if (Target->isDependentType()) return;
// Never diagnose implicit casts to bool.
if (Target->isSpecificBuiltinType(BuiltinType::Bool))
@@ -2147,7 +2151,7 @@ void Sema::CheckImplicitConversion(Expr *E, QualType T) {
// Strip vector types.
if (isa<VectorType>(Source)) {
if (!isa<VectorType>(Target))
- return DiagnoseImpCast(*this, E, T, diag::warn_impcast_vector_scalar);
+ return DiagnoseImpCast(S, E, T, diag::warn_impcast_vector_scalar);
Source = cast<VectorType>(Source)->getElementType().getTypePtr();
Target = cast<VectorType>(Target)->getElementType().getTypePtr();
@@ -2156,7 +2160,7 @@ void Sema::CheckImplicitConversion(Expr *E, QualType T) {
// Strip complex types.
if (isa<ComplexType>(Source)) {
if (!isa<ComplexType>(Target))
- return DiagnoseImpCast(*this, E, T, diag::warn_impcast_complex_scalar);
+ return DiagnoseImpCast(S, E, T, diag::warn_impcast_complex_scalar);
Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
@@ -2176,15 +2180,15 @@ void Sema::CheckImplicitConversion(Expr *E, QualType T) {
// Don't warn about float constants that are precisely
// representable in the target type.
Expr::EvalResult result;
- if (E->Evaluate(result, Context)) {
+ if (E->Evaluate(result, S.Context)) {
// Value might be a float, a float vector, or a float complex.
if (IsSameFloatAfterCast(result.Val,
- Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
- Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
+ S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
+ S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
return;
}
- DiagnoseImpCast(*this, E, T, diag::warn_impcast_float_precision);
+ DiagnoseImpCast(S, E, T, diag::warn_impcast_float_precision);
}
return;
}
@@ -2192,7 +2196,7 @@ void Sema::CheckImplicitConversion(Expr *E, QualType T) {
// If the target is integral, always warn.
if ((TargetBT && TargetBT->isInteger()))
// TODO: don't warn for integer values?
- return DiagnoseImpCast(*this, E, T, diag::warn_impcast_float_integer);
+ DiagnoseImpCast(S, E, T, diag::warn_impcast_float_integer);
return;
}
@@ -2200,22 +2204,158 @@ void Sema::CheckImplicitConversion(Expr *E, QualType T) {
if (!Source->isIntegerType() || !Target->isIntegerType())
return;
- IntRange SourceRange = GetExprRange(Context, E, Context.getIntWidth(E->getType()));
- IntRange TargetRange = IntRange::forCanonicalType(Context, Target);
-
- // FIXME: also signed<->unsigned?
+ IntRange SourceRange = GetExprRange(S.Context, E);
+ IntRange TargetRange = IntRange::forCanonicalType(S.Context, Target);
if (SourceRange.Width > TargetRange.Width) {
// People want to build with -Wshorten-64-to-32 and not -Wconversion
// and by god we'll let them.
if (SourceRange.Width == 64 && TargetRange.Width == 32)
- return DiagnoseImpCast(*this, E, T, diag::warn_impcast_integer_64_32);
- return DiagnoseImpCast(*this, E, T, diag::warn_impcast_integer_precision);
+ return DiagnoseImpCast(S, E, T, diag::warn_impcast_integer_64_32);
+ return DiagnoseImpCast(S, E, T, diag::warn_impcast_integer_precision);
+ }
+
+ if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
+ (!TargetRange.NonNegative && SourceRange.NonNegative &&
+ SourceRange.Width == TargetRange.Width)) {
+ unsigned DiagID = diag::warn_impcast_integer_sign;
+
+ // Traditionally, gcc has warned about this under -Wsign-compare.
+ // We also want to warn about it in -Wconversion.
+ // So if -Wconversion is off, use a completely identical diagnostic
+ // in the sign-compare group.
+ // The conditional-checking code will
+ if (ICContext) {
+ DiagID = diag::warn_impcast_integer_sign_conditional;
+ *ICContext = true;
+ }
+
+ return DiagnoseImpCast(S, E, T, DiagID);
}
return;
}
+void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T);
+
+void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
+ bool &ICContext) {
+ E = E->IgnoreParenImpCasts();
+
+ if (isa<ConditionalOperator>(E))
+ return CheckConditionalOperator(S, cast<ConditionalOperator>(E), T);
+
+ AnalyzeImplicitConversions(S, E);
+ if (E->getType() != T)
+ return CheckImplicitConversion(S, E, T, &ICContext);
+ return;
+}
+
+void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T) {
+ AnalyzeImplicitConversions(S, E->getCond());
+
+ bool Suspicious = false;
+ CheckConditionalOperand(S, E->getTrueExpr(), T, Suspicious);
+ CheckConditionalOperand(S, E->getFalseExpr(), T, Suspicious);
+
+ // If -Wconversion would have warned about either of the candidates
+ // for a signedness conversion to the context type...
+ if (!Suspicious) return;
+
+ // ...but it's currently ignored...
+ if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional))
+ return;
+
+ // ...and -Wsign-compare isn't...
+ if (!S.Diags.getDiagnosticLevel(diag::warn_mixed_sign_conditional))
+ return;
+
+ // ...then check whether it would have warned about either of the
+ // candidates for a signedness conversion to the condition type.
+ if (E->getType() != T) {
+ Suspicious = false;
+ CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
+ E->getType(), &Suspicious);
+ if (!Suspicious)
+ CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
+ E->getType(), &Suspicious);
+ if (!Suspicious)
+ return;
+ }
+
+ // If so, emit a diagnostic under -Wsign-compare.
+ Expr *lex = E->getTrueExpr()->IgnoreParenImpCasts();
+ Expr *rex = E->getFalseExpr()->IgnoreParenImpCasts();
+ S.Diag(E->getQuestionLoc(), diag::warn_mixed_sign_conditional)
+ << lex->getType() << rex->getType()
+ << lex->getSourceRange() << rex->getSourceRange();
+}
+
+/// AnalyzeImplicitConversions - Find and report any interesting
+/// implicit conversions in the given expression. There are a couple
+/// of competing diagnostics here, -Wconversion and -Wsign-compare.
+void AnalyzeImplicitConversions(Sema &S, Expr *OrigE) {
+ QualType T = OrigE->getType();
+ Expr *E = OrigE->IgnoreParenImpCasts();
+
+ // For conditional operators, we analyze the arguments as if they
+ // were being fed directly into the output.
+ if (isa<ConditionalOperator>(E)) {
+ ConditionalOperator *CO = cast<ConditionalOperator>(E);
+ CheckConditionalOperator(S, CO, T);
+ return;
+ }
+
+ // Go ahead and check any implicit conversions we might have skipped.
+ // The non-canonical typecheck is just an optimization;
+ // CheckImplicitConversion will filter out dead implicit conversions.
+ if (E->getType() != T)
+ CheckImplicitConversion(S, E, T);
+
+ // Now continue drilling into this expression.
+
+ // Skip past explicit casts.
+ if (isa<ExplicitCastExpr>(E)) {
+ E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
+ return AnalyzeImplicitConversions(S, E);
+ }
+
+ // Do a somewhat different check with comparison operators.
+ if (isa<BinaryOperator>(E) && cast<BinaryOperator>(E)->isComparisonOp())
+ return AnalyzeComparison(S, cast<BinaryOperator>(E));
+
+ // These break the otherwise-useful invariant below. Fortunately,
+ // we don't really need to recurse into them, because any internal
+ // expressions should have been analyzed already when they were
+ // built into statements.
+ if (isa<StmtExpr>(E)) return;
+
+ // Don't descend into unevaluated contexts.
+ if (isa<SizeOfAlignOfExpr>(E)) return;
+
+ // Now just recurse over the expression's children.
+ for (Stmt::child_iterator I = E->child_begin(), IE = E->child_end();
+ I != IE; ++I)
+ AnalyzeImplicitConversions(S, cast<Expr>(*I));
+}
+
+} // end anonymous namespace
+
+/// Diagnoses "dangerous" implicit conversions within the given
+/// expression (which is a full expression). Implements -Wconversion
+/// and -Wsign-compare.
+void Sema::CheckImplicitConversions(Expr *E) {
+ // Don't diagnose in unevaluated contexts.
+ if (ExprEvalContexts.back().Context == Sema::Unevaluated)
+ return;
+
+ // Don't diagnose for value- or type-dependent expressions.
+ if (E->isTypeDependent() || E->isValueDependent())
+ return;
+
+ AnalyzeImplicitConversions(*this, E);
+}
+
/// CheckParmsForFunctionDef - Check that the parameters of the given
/// function are appropriate for the definition of a function. This
/// takes care of any checks that cannot be performed on the
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