Author: dcoughlin Date: Sun Dec 3 20:46:47 2017 New Revision: 319638 URL: http://llvm.org/viewvc/llvm-project?rev=319638&view=rev Log: [analyzer] Don't treat lambda-captures float constexprs as undefined
RegionStore has special logic to evaluate captured constexpr variables. However, if the constexpr initializer cannot be evaluated as an integer, the value is treated as undefined. This leads to false positives when, for example, a constexpr float is captured by a lambda. To fix this, treat a constexpr capture that cannot be evaluated as unknown rather than undefined. rdar://problem/35784662 Modified: cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp cfe/trunk/test/Analysis/lambdas.cpp Modified: cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp?rev=319638&r1=319637&r2=319638&view=diff ============================================================================== --- cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp (original) +++ cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp Sun Dec 3 20:46:47 2017 @@ -1864,11 +1864,18 @@ SVal RegionStoreManager::getBindingForVa return svalBuilder.getRegionValueSymbolVal(R); // Is 'VD' declared constant? If so, retrieve the constant value. - if (VD->getType().isConstQualified()) - if (const Expr *Init = VD->getInit()) + if (VD->getType().isConstQualified()) { + if (const Expr *Init = VD->getInit()) { if (Optional<SVal> V = svalBuilder.getConstantVal(Init)) return *V; + // If the variable is const qualified and has an initializer but + // we couldn't evaluate initializer to a value, treat the value as + // unknown. + return UnknownVal(); + } + } + // This must come after the check for constants because closure-captured // constant variables may appear in UnknownSpaceRegion. if (isa<UnknownSpaceRegion>(MS)) Modified: cfe/trunk/test/Analysis/lambdas.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/lambdas.cpp?rev=319638&r1=319637&r2=319638&view=diff ============================================================================== --- cfe/trunk/test/Analysis/lambdas.cpp (original) +++ cfe/trunk/test/Analysis/lambdas.cpp Sun Dec 3 20:46:47 2017 @@ -337,6 +337,16 @@ void captureByReference() { lambda2(); } +void testCapturedConstExprFloat() { + constexpr float localConstant = 4.0; + auto lambda = []{ + // Don't treat localConstant as containing a garbage value + float copy = localConstant; // no-warning + (void)copy; + }; + + lambda(); +} // CHECK: [B2 (ENTRY)] // CHECK: Succs (1): B1 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits