Index: cfe/trunk/lib/StaticAnalyzer/Checkers/EnumCastOutOfRangeChecker.cpp =================================================================== --- cfe/trunk/lib/StaticAnalyzer/Checkers/EnumCastOutOfRangeChecker.cpp +++ cfe/trunk/lib/StaticAnalyzer/Checkers/EnumCastOutOfRangeChecker.cpp @@ -91,6 +91,22 @@ void EnumCastOutOfRangeChecker::checkPreStmt(const CastExpr *CE, CheckerContext &C) const { + + // Only perform enum range check on casts where such checks are valid. For + // all other cast kinds (where enum range checks are unnecessary or invalid), + // just return immediately. TODO: The set of casts whitelisted for enum + // range checking may be incomplete. Better to add a missing cast kind to + // enable a missing check than to generate false negatives and have to remove + // those later. + switch (CE->getCastKind()) { + case CK_IntegralCast: + break; + + default: + return; + break; + } + // Get the value of the expression to cast. const llvm::Optional ValueToCast = C.getSVal(CE->getSubExpr()).getAs(); Index: cfe/trunk/test/Analysis/enum-cast-out-of-range.c =================================================================== --- cfe/trunk/test/Analysis/enum-cast-out-of-range.c +++ cfe/trunk/test/Analysis/enum-cast-out-of-range.c @@ -0,0 +1,34 @@ +// RUN: %clang_analyze_cc1 \ +// RUN: -analyzer-checker=core,alpha.cplusplus.EnumCastOutOfRange \ +// RUN: -verify %s + +enum En_t { + En_0 = -4, + En_1, + En_2 = 1, + En_3, + En_4 = 4 +}; + +void unscopedUnspecifiedCStyle() { + enum En_t Below = (enum En_t)(-5); // expected-warning {{not in the valid range}} + enum En_t NegVal1 = (enum En_t)(-4); // OK. + enum En_t NegVal2 = (enum En_t)(-3); // OK. + enum En_t InRange1 = (enum En_t)(-2); // expected-warning {{not in the valid range}} + enum En_t InRange2 = (enum En_t)(-1); // expected-warning {{not in the valid range}} + enum En_t InRange3 = (enum En_t)(0); // expected-warning {{not in the valid range}} + enum En_t PosVal1 = (enum En_t)(1); // OK. + enum En_t PosVal2 = (enum En_t)(2); // OK. + enum En_t InRange4 = (enum En_t)(3); // expected-warning {{not in the valid range}} + enum En_t PosVal3 = (enum En_t)(4); // OK. + enum En_t Above = (enum En_t)(5); // expected-warning {{not in the valid range}} +} + +enum En_t unused; +void unusedExpr() { + // Following line is not something that EnumCastOutOfRangeChecker should + // evaluate. Checker should either ignore this line or process it without + // producing any warnings. However, compilation will (and should) still + // generate a warning having nothing to do with this checker. + unused; // expected-warning {{expression result unused}} +} Index: cfe/trunk/test/Analysis/enum-cast-out-of-range.cpp =================================================================== --- cfe/trunk/test/Analysis/enum-cast-out-of-range.cpp +++ cfe/trunk/test/Analysis/enum-cast-out-of-range.cpp @@ -150,7 +150,15 @@ scoped_specified_t InvalidAfterRangeEnd = (scoped_specified_t)(5); // expected-warning {{The value provided to the cast expression is not in the valid range of values for the enum}} } -void rangeContstrained1(int input) { +unscoped_unspecified_t unused; +void unusedExpr() { + // following line is not something that EnumCastOutOfRangeChecker should evaluate. checker should either ignore this line + // or process it without producing any warnings. However, compilation will (and should) still generate a warning having + // nothing to do with this checker. + unused; // expected-warning {{expression result unused}} +} + +void rangeConstrained1(int input) { if (input > -5 && input < 5) auto value = static_cast(input); // OK. Being conservative, this is a possibly good value. }