From fa098713201a6999ec4c12d0a8bde0adcf47b095 Mon Sep 17 00:00:00 2001 From: MarcoFalke Date: Thu, 29 Apr 2021 08:50:06 +0200 Subject: [PATCH] refactor: Avoid sign-compare compiler warning in util/asmap This reverts commit eac6a3080d38cfd4eb7204ecd327df213958e51a ("refactor: Rework asmap Interpret to avoid ptrdiff_t"), because it is UB to form a past-the-end iterator, even if it is never dereferenced. Then fix the compiler warning in a different way: Instead of comparing an uint32_t against a signed ptrdiff_t, just promote both to a type that can represent both types. Even though in this case the ptrdiff_t should never hold a negative value, the overhead from promotion should be negligible. --- src/util/asmap.cpp | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/src/util/asmap.cpp b/src/util/asmap.cpp index bd77d7421850d..bacc3690a2006 100644 --- a/src/util/asmap.cpp +++ b/src/util/asmap.cpp @@ -93,8 +93,7 @@ uint32_t Interpret(const std::vector &asmap, const std::vector &ip) jump = DecodeJump(pos, endpos); if (jump == INVALID) break; // Jump offset straddles EOF if (bits == 0) break; // No input bits left - if (pos + jump < pos) break; // overflow - if (pos + jump >= endpos) break; // Jumping past EOF + if (int64_t{jump} >= int64_t{endpos - pos}) break; // Jumping past EOF if (ip[ip.size() - bits]) { pos += jump; } @@ -156,8 +155,7 @@ bool SanityCheckASMap(const std::vector& asmap, int bits) } else if (opcode == Instruction::JUMP) { uint32_t jump = DecodeJump(pos, endpos); if (jump == INVALID) return false; // Jump offset straddles EOF - if (pos + jump < pos) return false; // overflow - if (pos + jump > endpos) return false; // Jump out of range + if (int64_t{jump} > int64_t{endpos - pos}) return false; // Jump out of range if (bits == 0) return false; // Consuming bits past the end of the input --bits; uint32_t jump_offset = pos - begin + jump;