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| author | alkondratenko@gmail.com <alkondratenko@gmail.com@6b5cf1ce-ec42-a296-1ba9-69fdba395a50> | 2013-05-07 19:22:45 +0000 |
|---|---|---|
| committer | alkondratenko@gmail.com <alkondratenko@gmail.com@6b5cf1ce-ec42-a296-1ba9-69fdba395a50> | 2013-05-07 19:22:45 +0000 |
| commit | c45bb7d6033952ea33bb181c1f96999317b535a1 (patch) | |
| tree | 81ec01c867550e87cd5fc4e8f6598f790abefaf3 | |
| parent | 3567b1701aa55a6421aefa5f3de1ca5507cbdf79 (diff) | |
| download | gperftools-c45bb7d6033952ea33bb181c1f96999317b535a1.tar.gz | |
issue-511: fixed negative offset handling for conditional jumps
While doing and testing issue-511 I've found one subtle bug which is
incorrect handling of short offsets. They are defined to be signed but
previous code used unsigned char for them which caused negative
offsets to look like larger positive offsets. Fix is trivial.
git-svn-id: http://gperftools.googlecode.com/svn/trunk@215 6b5cf1ce-ec42-a296-1ba9-69fdba395a50
| -rw-r--r-- | src/windows/preamble_patcher.cc | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/src/windows/preamble_patcher.cc b/src/windows/preamble_patcher.cc index 51a5af7..59624f0 100644 --- a/src/windows/preamble_patcher.cc +++ b/src/windows/preamble_patcher.cc @@ -594,7 +594,9 @@ SideStepError PreamblePatcher::PatchShortConditionalJump( unsigned char* target, unsigned int* target_bytes, unsigned int target_size) { - unsigned char* original_jump_dest = (source + 2) + source[1]; + // note: rel8 offset is signed. Thus we need to ask for signed char + // to negative offsets right + unsigned char* original_jump_dest = (source + 2) + static_cast<signed char>(source[1]); unsigned char* stub_jump_from = target + 6; __int64 fixup_jump_offset = original_jump_dest - stub_jump_from; if (fixup_jump_offset > INT_MAX || fixup_jump_offset < INT_MIN) { |