Author: Timm Baeder Date: 2025-12-01T12:43:35+01:00 New Revision: 48931e5e5942304afd1c0a493be91b662ffd221b
URL: https://github.com/llvm/llvm-project/commit/48931e5e5942304afd1c0a493be91b662ffd221b DIFF: https://github.com/llvm/llvm-project/commit/48931e5e5942304afd1c0a493be91b662ffd221b.diff LOG: [clang][bytecode] Check memcmp builtin for one-past-the-end pointers (#170097) We can't read from those and will run into an assertion sooner or later. Fixes https://github.com/llvm/llvm-project/issues/170031 Added: Modified: clang/lib/AST/ByteCode/InterpBuiltin.cpp clang/test/AST/ByteCode/builtin-functions.cpp Removed: ################################################################################ diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp index 8496b58105c7a..971fce541bb88 100644 --- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp +++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp @@ -1921,6 +1921,10 @@ static bool interp__builtin_memcmp(InterpState &S, CodePtr OpPC, if (PtrA.isDummy() || PtrB.isDummy()) return false; + if (!CheckRange(S, OpPC, PtrA, AK_Read) || + !CheckRange(S, OpPC, PtrB, AK_Read)) + return false; + // Now, read both pointers to a buffer and compare those. BitcastBuffer BufferA( Bits(ASTCtx.getTypeSize(ElemTypeA) * PtrA.getNumElems())); diff --git a/clang/test/AST/ByteCode/builtin-functions.cpp b/clang/test/AST/ByteCode/builtin-functions.cpp index 4a53cb66b2fdd..3076b5239ebbe 100644 --- a/clang/test/AST/ByteCode/builtin-functions.cpp +++ b/clang/test/AST/ByteCode/builtin-functions.cpp @@ -1545,6 +1545,13 @@ namespace Memcmp { int unknown; void foo(void) { unknown *= __builtin_memcmp(0, 0, 2); } + + constexpr int onepasttheend(char a) { + __builtin_memcmp(&a, &a + 1, 1); // both-note {{read of dereferenced one-past-the-end pointer}} + return 1; + } + static_assert(onepasttheend(10)); // both-error {{not an integral constant expression}} \ + // both-note {{in call to}} } namespace Memchr { _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
