Author: dgoldman Date: Fri Sep 13 07:43:24 2019 New Revision: 371859 URL: http://llvm.org/viewvc/llvm-project?rev=371859&view=rev Log: [Sema][Typo Correction] Fix potential infite loop on ambiguity checks
Summary: This fixes a bug introduced in D62648, where Clang could infinite loop if it became stuck on a single TypoCorrection when it was supposed to be testing ambiguous corrections. Although not a common case, it could happen if there are multiple possible corrections with the same edit distance. The fix is simply to wipe the TypoExpr from the `TransformCache` so that the call to `TransformTypoExpr` doesn't use the `CachedEntry`. Reviewers: rsmith Subscribers: cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D67515 Added: cfe/trunk/test/Sema/typo-correction-ambiguity.cpp Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=371859&r1=371858&r2=371859&view=diff ============================================================================== --- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original) +++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Fri Sep 13 07:43:24 2019 @@ -7755,6 +7755,10 @@ class TransformTypos : public TreeTransf TypoCorrection TC = SemaRef.getTypoExprState(TE).Consumer->peekNextCorrection(); TypoCorrection Next; do { + // Fetch the next correction by erasing the typo from the cache and calling + // `TryTransform` which will iterate through corrections in + // `TransformTypoExpr`. + TransformCache.erase(TE); ExprResult AmbigRes = CheckForRecursiveTypos(TryTransform(E), IsAmbiguous); if (!AmbigRes.isInvalid() || IsAmbiguous) { Added: cfe/trunk/test/Sema/typo-correction-ambiguity.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/typo-correction-ambiguity.cpp?rev=371859&view=auto ============================================================================== --- cfe/trunk/test/Sema/typo-correction-ambiguity.cpp (added) +++ cfe/trunk/test/Sema/typo-correction-ambiguity.cpp Fri Sep 13 07:43:24 2019 @@ -0,0 +1,29 @@ +// RUN: %clang_cc1 -fsyntax-only -verify %s + +// Check the following typo correction behavior in namespaces: +// - no typos are diagnosed when an expression has ambiguous (multiple) corrections +// - proper iteration through multiple potentially ambiguous corrections + +namespace AmbiguousCorrection +{ + void method_Bar(); + void method_Foo(); + void method_Zoo(); +}; + +void testAmbiguousNoSuggestions() +{ + AmbiguousCorrection::method_Ace(); // expected-error {{no member named 'method_Ace' in namespace 'AmbiguousCorrection'}} +} + +namespace MultipleCorrectionsButNotAmbiguous +{ + int PrefixType_Name(int value); // expected-note {{'PrefixType_Name' declared here}} + int PrefixType_MIN(); + int PrefixType_MAX(); +}; + +int testMultipleCorrectionsButNotAmbiguous() { + int val = MultipleCorrectionsButNotAmbiguous::PrefixType_Enum(0); // expected-error {{no member named 'PrefixType_Enum' in namespace 'MultipleCorrectionsButNotAmbiguous'; did you mean 'PrefixType_Name'?}} + return val; +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
