https://github.com/Benjins created https://github.com/llvm/llvm-project/pull/224873
Previously, this was applying the offset it would for non-null pointers, but null pointers should always cast to a null pointer result. Fixes https://github.com/llvm/llvm-project/issues/224869 >From 940c0518978692b0a339bc909264b0e93f411f62 Mon Sep 17 00:00:00 2001 From: Benji Smith <[email protected]> Date: Sat, 19 Sep 2026 19:17:18 -0400 Subject: [PATCH] [clang][bytecode] Fix null ptr upcasts adding offset Previously, this was applying the offset it would for non-null pointers, but null pointers should always cast to a null pointer result. Fixes https://github.com/llvm/llvm-project/issues/224869 --- clang/docs/ReleaseNotes.md | 3 +++ clang/lib/AST/ByteCode/Pointer.cpp | 4 ++++ clang/test/AST/ByteCode/const-base-cast.cpp | 5 +++++ 3 files changed, 12 insertions(+) diff --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md index a1f24a8caedae..684b02fb0af1a 100644 --- a/clang/docs/ReleaseNotes.md +++ b/clang/docs/ReleaseNotes.md @@ -727,6 +727,9 @@ features cannot lower the translation-unit ABI level; - Fixed ambiguous overload where two non-static member functions with different signatures could be incorrectly considered equivalent. (#GH224499) +- Fixed the bytecode interpreter evaluating upcasted null pointers to a + non-null pointer. (#GH224869) + #### Bug Fixes to AST Handling - Fixed a non-deterministic ordering of unused local typedefs that made diff --git a/clang/lib/AST/ByteCode/Pointer.cpp b/clang/lib/AST/ByteCode/Pointer.cpp index dca2630138a4e..fb05efe5a62c3 100644 --- a/clang/lib/AST/ByteCode/Pointer.cpp +++ b/clang/lib/AST/ByteCode/Pointer.cpp @@ -1373,6 +1373,10 @@ IntPointer IntPointer::baseCast(const interp::Context &Ctx, if (CurType.isNull() || !CurType->isRecordType()) return *this; + // null pointers stay null during a cast, per conv.ptr + if (Value == 0) + return *this; + const Record *R = Ctx.getRecord(CurType->getAsRecordDecl()); // This iterates over bases and checks for the proper offset. That's diff --git a/clang/test/AST/ByteCode/const-base-cast.cpp b/clang/test/AST/ByteCode/const-base-cast.cpp index 80226b973bf97..696eff5959cc4 100644 --- a/clang/test/AST/ByteCode/const-base-cast.cpp +++ b/clang/test/AST/ByteCode/const-base-cast.cpp @@ -17,3 +17,8 @@ unsigned char y = ((char*)(B*)(C*)0x1000) - (char*)0x1000; unsigned char z = ((char*)(A*)(C*)0x1000) - (char*)0x1000; // CHECK: @z = {{(dso_local )?}}global i8 0 +unsigned char n0 = ((char*)(B*)(C*)0) - (char*)0; +// CHECK: @n0 = {{(dso_local )?}}global i8 0 + +unsigned char n1 = ((char*)(A*)(C*)0) - (char*)0; +// CHECK: @n1 = {{(dso_local )?}}global i8 0 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
