Author: rtrieu Date: Fri May 3 21:22:33 2019 New Revision: 359960 URL: http://llvm.org/viewvc/llvm-project?rev=359960&view=rev Log: Reduce amount of work ODR hashing does.
When a FunctionProtoType is in the original type in a DecayedType, the decayed type is a PointerType which points back the original FunctionProtoType. The visitor for ODRHashing will attempt to process both Type's, doing double work. By chaining together multiple DecayedType's and FunctionProtoType's, this would result in 2^N Type's visited only N DecayedType's and N FunctionProtoType's exsit. Another bug where VisitDecayedType and VisitAdjustedType did redundant work doubled the work at each level, giving 4^N Type's visited. This patch removed the double work and detects when a FunctionProtoType decays to itself to only check the Type once. This lowers the exponential runtime to linear runtime. Fixes https://bugs.llvm.org/show_bug.cgi?id=41625 Modified: cfe/trunk/lib/AST/ODRHash.cpp cfe/trunk/test/Modules/odr_hash.cpp Modified: cfe/trunk/lib/AST/ODRHash.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ODRHash.cpp?rev=359960&r1=359959&r2=359960&view=diff ============================================================================== --- cfe/trunk/lib/AST/ODRHash.cpp (original) +++ cfe/trunk/lib/AST/ODRHash.cpp Fri May 3 21:22:33 2019 @@ -703,14 +703,36 @@ public: void VisitType(const Type *T) {} void VisitAdjustedType(const AdjustedType *T) { - AddQualType(T->getOriginalType()); - AddQualType(T->getAdjustedType()); + QualType Original = T->getOriginalType(); + QualType Adjusted = T->getAdjustedType(); + + // The original type and pointee type can be the same, as in the case of + // function pointers decaying to themselves. Set a bool and only process + // the type once, to prevent doubling the work. + SplitQualType split = Adjusted.split(); + if (auto Pointer = dyn_cast<PointerType>(split.Ty)) { + if (Pointer->getPointeeType() == Original) { + Hash.AddBoolean(true); + ID.AddInteger(split.Quals.getAsOpaqueValue()); + AddQualType(Original); + VisitType(T); + return; + } + } + + // The original type and pointee type are different, such as in the case + // of a array decaying to an element pointer. Set a bool to false and + // process both types. + Hash.AddBoolean(false); + AddQualType(Original); + AddQualType(Adjusted); + VisitType(T); } void VisitDecayedType(const DecayedType *T) { - AddQualType(T->getDecayedType()); - AddQualType(T->getPointeeType()); + // getDecayedType and getPointeeType are derived from getAdjustedType + // and don't need to be separately processed. VisitAdjustedType(T); } Modified: cfe/trunk/test/Modules/odr_hash.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/odr_hash.cpp?rev=359960&r1=359959&r2=359960&view=diff ============================================================================== --- cfe/trunk/test/Modules/odr_hash.cpp (original) +++ cfe/trunk/test/Modules/odr_hash.cpp Fri May 3 21:22:33 2019 @@ -4587,6 +4587,43 @@ int num = bar(); #endif } +namespace FunctionProtoTypeDecay { +#if defined(FIRST) +struct S1 { + struct X {}; + using Y = X(X()); +}; +#elif defined(SECOND) +struct S1 { + struct X {}; + using Y = X(X(X())); +}; +#else +S1 s1; +// expected-error@first.h:* {{'FunctionProtoTypeDecay::S1::Y' from module 'FirstModule' is not present in definition of 'FunctionProtoTypeDecay::S1' in module 'SecondModule'}} +// expected-note@second.h:* {{declaration of 'Y' does not match}} +#endif + +#if defined(FIRST) +struct S2 { + struct X {}; + using Y = + X(X(X(X(X(X(X(X(X(X(X(X(X(X(X(X( + X(X(X(X(X(X(X(X(X(X(X(X(X(X(X(X( + X(X(X(X(X(X(X(X(X(X(X(X(X(X(X(X( + X(X(X(X(X(X(X(X(X(X(X(X(X(X(X(X( + )))))))))))))))) + )))))))))))))))) + )))))))))))))))) + )))))))))))))))); +}; +#elif defined(SECOND) +#else +S2 s2; +#endif + +} + // Keep macros contained to one file. #ifdef FIRST #undef FIRST _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
