r299523 - [analyzer] alpha.core.Conversion - Fix false positive for 'U32 += S16; ' expression, that is not unsafe
Daniel Marjamaki via cfe-commits
cfe-commits at lists.llvm.org
Wed Apr 5 01:57:04 PDT 2017
Author: danielmarjamaki
Date: Wed Apr 5 03:57:04 2017
New Revision: 299523
URL: http://llvm.org/viewvc/llvm-project?rev=299523&view=rev
Log:
[analyzer] alpha.core.Conversion - Fix false positive for 'U32 += S16;' expression, that is not unsafe
Summary:
The alpha.core.Conversion was too strict about compound assignments and could warn even though there is no problem.
Differential Revision: https://reviews.llvm.org/D25596
Modified:
cfe/trunk/lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
cfe/trunk/test/Analysis/conversion.c
Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/ConversionChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/ConversionChecker.cpp?rev=299523&r1=299522&r2=299523&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/ConversionChecker.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/ConversionChecker.cpp Wed Apr 5 03:57:04 2017
@@ -41,7 +41,8 @@ private:
mutable std::unique_ptr<BuiltinBug> BT;
// Is there loss of precision
- bool isLossOfPrecision(const ImplicitCastExpr *Cast, CheckerContext &C) const;
+ bool isLossOfPrecision(const ImplicitCastExpr *Cast, QualType DestType,
+ CheckerContext &C) const;
// Is there loss of sign
bool isLossOfSign(const ImplicitCastExpr *Cast, CheckerContext &C) const;
@@ -73,16 +74,30 @@ void ConversionChecker::checkPreStmt(con
// Loss of sign/precision in binary operation.
if (const auto *B = dyn_cast<BinaryOperator>(Parent)) {
BinaryOperator::Opcode Opc = B->getOpcode();
- if (Opc == BO_Assign || Opc == BO_AddAssign || Opc == BO_SubAssign ||
- Opc == BO_MulAssign) {
+ if (Opc == BO_Assign) {
LossOfSign = isLossOfSign(Cast, C);
- LossOfPrecision = isLossOfPrecision(Cast, C);
+ LossOfPrecision = isLossOfPrecision(Cast, Cast->getType(), C);
+ } else if (Opc == BO_AddAssign || Opc == BO_SubAssign) {
+ // No loss of sign.
+ LossOfPrecision = isLossOfPrecision(Cast, B->getLHS()->getType(), C);
+ } else if (Opc == BO_MulAssign) {
+ LossOfSign = isLossOfSign(Cast, C);
+ LossOfPrecision = isLossOfPrecision(Cast, B->getLHS()->getType(), C);
+ } else if (Opc == BO_DivAssign || Opc == BO_RemAssign) {
+ LossOfSign = isLossOfSign(Cast, C);
+ // No loss of precision.
+ } else if (Opc == BO_AndAssign) {
+ LossOfSign = isLossOfSign(Cast, C);
+ // No loss of precision.
+ } else if (Opc == BO_OrAssign || Opc == BO_XorAssign) {
+ LossOfSign = isLossOfSign(Cast, C);
+ LossOfPrecision = isLossOfPrecision(Cast, B->getLHS()->getType(), C);
} else if (B->isRelationalOp() || B->isMultiplicativeOp()) {
LossOfSign = isLossOfSign(Cast, C);
}
} else if (isa<DeclStmt>(Parent)) {
LossOfSign = isLossOfSign(Cast, C);
- LossOfPrecision = isLossOfPrecision(Cast, C);
+ LossOfPrecision = isLossOfPrecision(Cast, Cast->getType(), C);
}
if (LossOfSign || LossOfPrecision) {
@@ -113,6 +128,13 @@ static bool isGreaterEqual(CheckerContex
unsigned long long Val) {
ProgramStateRef State = C.getState();
SVal EVal = C.getSVal(E);
+ if (EVal.isUnknownOrUndef())
+ return false;
+ if (!EVal.getAs<NonLoc>() && EVal.getAs<Loc>()) {
+ ProgramStateManager &Mgr = C.getStateManager();
+ EVal =
+ Mgr.getStoreManager().getBinding(State->getStore(), EVal.castAs<Loc>());
+ }
if (EVal.isUnknownOrUndef() || !EVal.getAs<NonLoc>())
return false;
@@ -153,22 +175,22 @@ static bool isNegative(CheckerContext &C
}
bool ConversionChecker::isLossOfPrecision(const ImplicitCastExpr *Cast,
- CheckerContext &C) const {
+ QualType DestType,
+ CheckerContext &C) const {
// Don't warn about explicit loss of precision.
if (Cast->isEvaluatable(C.getASTContext()))
return false;
- QualType CastType = Cast->getType();
QualType SubType = Cast->IgnoreParenImpCasts()->getType();
- if (!CastType->isIntegerType() || !SubType->isIntegerType())
+ if (!DestType->isIntegerType() || !SubType->isIntegerType())
return false;
- if (C.getASTContext().getIntWidth(CastType) >=
+ if (C.getASTContext().getIntWidth(DestType) >=
C.getASTContext().getIntWidth(SubType))
return false;
- unsigned W = C.getASTContext().getIntWidth(CastType);
+ unsigned W = C.getASTContext().getIntWidth(DestType);
if (W == 1 || W >= 64U)
return false;
Modified: cfe/trunk/test/Analysis/conversion.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/conversion.c?rev=299523&r1=299522&r2=299523&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/conversion.c (original)
+++ cfe/trunk/test/Analysis/conversion.c Wed Apr 5 03:57:04 2017
@@ -9,9 +9,67 @@ void assign(unsigned U, signed S) {
if (U > 300)
S8 = U; // expected-warning {{Loss of precision in implicit conversion}}
if (S > 10)
- U8 = S;
+ U8 = S; // no-warning
if (U < 200)
- S8 = U;
+ S8 = U; // no-warning
+}
+
+void addAssign() {
+ unsigned long L = 1000;
+ int I = -100;
+ U8 += L; // expected-warning {{Loss of precision in implicit conversion}}
+ L += I; // no-warning
+}
+
+void subAssign() {
+ unsigned long L = 1000;
+ int I = -100;
+ U8 -= L; // expected-warning {{Loss of precision in implicit conversion}}
+ L -= I; // no-warning
+}
+
+void mulAssign() {
+ unsigned long L = 1000;
+ int I = -1;
+ U8 *= L; // expected-warning {{Loss of precision in implicit conversion}}
+ L *= I; // expected-warning {{Loss of sign in implicit conversion}}
+ I = 10;
+ L *= I; // no-warning
+}
+
+void divAssign() {
+ unsigned long L = 1000;
+ int I = -1;
+ U8 /= L; // no-warning
+ L /= I; // expected-warning {{Loss of sign in implicit conversion}}
+}
+
+void remAssign() {
+ unsigned long L = 1000;
+ int I = -1;
+ U8 %= L; // no-warning
+ L %= I; // expected-warning {{Loss of sign in implicit conversion}}
+}
+
+void andAssign() {
+ unsigned long L = 1000;
+ int I = -1;
+ U8 &= L; // no-warning
+ L &= I; // expected-warning {{Loss of sign in implicit conversion}}
+}
+
+void orAssign() {
+ unsigned long L = 1000;
+ int I = -1;
+ U8 |= L; // expected-warning {{Loss of precision in implicit conversion}}
+ L |= I; // expected-warning {{Loss of sign in implicit conversion}}
+}
+
+void xorAssign() {
+ unsigned long L = 1000;
+ int I = -1;
+ U8 ^= L; // expected-warning {{Loss of precision in implicit conversion}}
+ L ^= I; // expected-warning {{Loss of sign in implicit conversion}}
}
void init1() {
@@ -21,7 +79,7 @@ void init1() {
void relational(unsigned U, signed S) {
if (S > 10) {
- if (U < S) {
+ if (U < S) { // no-warning
}
}
if (S < -10) {
@@ -32,14 +90,14 @@ void relational(unsigned U, signed S) {
void multiplication(unsigned U, signed S) {
if (S > 5)
- S = U * S;
+ S = U * S; // no-warning
if (S < -10)
S = U * S; // expected-warning {{Loss of sign}}
}
void division(unsigned U, signed S) {
if (S > 5)
- S = U / S;
+ S = U / S; // no-warning
if (S < -10)
S = U / S; // expected-warning {{Loss of sign}}
}
More information about the cfe-commits
mailing list