Author: Malavika Samak Date: 2024-11-11T16:47:28-08:00 New Revision: da032a609c1bde6f6775cf1650e08a205920d920
URL: https://github.com/llvm/llvm-project/commit/da032a609c1bde6f6775cf1650e08a205920d920 DIFF: https://github.com/llvm/llvm-project/commit/da032a609c1bde6f6775cf1650e08a205920d920.diff LOG: [Wunsafe-buffer-usage] Fix false positives in handling string literals. (#115552) Do not warn when a string literal is indexed and the idex value is within the bounds of the length of the string. (rdar://139106996) Co-authored-by: MalavikaSamak <malavi...@apple.com> Added: Modified: clang/lib/Analysis/UnsafeBufferUsage.cpp clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp Removed: ################################################################################ diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp b/clang/lib/Analysis/UnsafeBufferUsage.cpp index 2c68409b846bc8..b683826503c74c 100644 --- a/clang/lib/Analysis/UnsafeBufferUsage.cpp +++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp @@ -436,21 +436,31 @@ AST_MATCHER(ArraySubscriptExpr, isSafeArraySubscript) { const auto *BaseDRE = dyn_cast<DeclRefExpr>(Node.getBase()->IgnoreParenImpCasts()); - if (!BaseDRE) - return false; - if (!BaseDRE->getDecl()) - return false; - const auto *CATy = Finder->getASTContext().getAsConstantArrayType( - BaseDRE->getDecl()->getType()); - if (!CATy) + const auto *SLiteral = + dyn_cast<StringLiteral>(Node.getBase()->IgnoreParenImpCasts()); + uint64_t size; + + if (!BaseDRE && !SLiteral) return false; + if (BaseDRE) { + if (!BaseDRE->getDecl()) + return false; + const auto *CATy = Finder->getASTContext().getAsConstantArrayType( + BaseDRE->getDecl()->getType()); + if (!CATy) { + return false; + } + size = CATy->getLimitedSize(); + } else if (SLiteral) { + size = SLiteral->getLength() + 1; + } + if (const auto *IdxLit = dyn_cast<IntegerLiteral>(Node.getIdx())) { const APInt ArrIdx = IdxLit->getValue(); // FIXME: ArrIdx.isNegative() we could immediately emit an error as that's a // bug - if (ArrIdx.isNonNegative() && - ArrIdx.getLimitedValue() < CATy->getLimitedSize()) + if (ArrIdx.isNonNegative() && ArrIdx.getLimitedValue() < size) return true; } diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp b/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp index 8b2f103ec66708..c6c93a27e4b969 100644 --- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp +++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp @@ -38,3 +38,17 @@ void constant_idx_unsafe(unsigned idx) { // expected-note@-1{{change type of 'buffer' to 'std::array' to label it for hardening}} buffer[10] = 0; // expected-note{{used in buffer access here}} } + +void constant_id_string(unsigned idx) { + char safe_char = "abc"[1]; // no-warning + safe_char = ""[0]; + safe_char = "\0"[0]; + + char abcd[5] = "abc"; + abcd[2]; // no-warning + + char unsafe_char = "abc"[3]; + unsafe_char = "abc"[-1]; //expected-warning{{unsafe buffer access}} + unsafe_char = ""[1]; //expected-warning{{unsafe buffer access}} + unsafe_char = ""[idx]; //expected-warning{{unsafe buffer access}} +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
