Author: Ryan Prichard Date: 2020-07-15T19:12:56-07:00 New Revision: fd802cc4dea4ed1a233ff725f98c686dc2836bf3
URL: https://github.com/llvm/llvm-project/commit/fd802cc4dea4ed1a233ff725f98c686dc2836bf3 DIFF: https://github.com/llvm/llvm-project/commit/fd802cc4dea4ed1a233ff725f98c686dc2836bf3.diff LOG: [libunwind] Fix getSLEB128 on large values Previously, for large-enough values, getSLEB128 would attempt to shift a signed int in the range [0..0x7f] by 28, 35, 42... bits, which is undefined behavior and likely to fail. Avoid shifting (-1ULL) by 70 for large values. e.g. For INT64_MAX, the last two bytes will be: - 0x7f [bit==56] - 0x00 [bit==63] Differential Revision: https://reviews.llvm.org/D83742 Added: Modified: libunwind/src/AddressSpace.hpp Removed: ################################################################################ diff --git a/libunwind/src/AddressSpace.hpp b/libunwind/src/AddressSpace.hpp index a4564cb67328..764aaa3489f2 100644 --- a/libunwind/src/AddressSpace.hpp +++ b/libunwind/src/AddressSpace.hpp @@ -290,11 +290,11 @@ inline int64_t LocalAddressSpace::getSLEB128(pint_t &addr, pint_t end) { if (p == pend) _LIBUNWIND_ABORT("truncated sleb128 expression"); byte = *p++; - result |= ((byte & 0x7f) << bit); + result |= (uint64_t)(byte & 0x7f) << bit; bit += 7; } while (byte & 0x80); // sign extend negative numbers - if ((byte & 0x40) != 0) + if ((byte & 0x40) != 0 && bit < 64) result |= (-1ULL) << bit; addr = (pint_t) p; return result; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
