Fix signed char arithmetic shift in name escaping#8330
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sumleo wants to merge 1 commit intoWebAssembly:mainfrom
Open
Fix signed char arithmetic shift in name escaping#8330sumleo wants to merge 1 commit intoWebAssembly:mainfrom
sumleo wants to merge 1 commit intoWebAssembly:mainfrom
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In WasmBinaryReader::escape(), the loop variable 'char c' is signed on most platforms (x86, ARM). For bytes >= 0x80, 'c >> 4' performs an arithmetic right shift, producing negative values that formatNibble converts to wrong hex characters (e.g., 0xFF gives '/' instead of 'f'). Cast to unsigned char before shifting to ensure logical right shift.
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If the old code was incorrect, please add a testcase showing the problem. |
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Summary
WasmBinaryReader::escape(), the loop variablechar cis signed on most platforms (x86, ARM).c >> 4performs an arithmetic right shift, producing negative values thatformatNibbleconverts to incorrect hex characters (e.g., byte 0xFF produces\/finstead of\ff, byte 0xC0 produces wrong high nibble, etc.).unsigned charbefore shifting and masking to ensure correct hex encoding of non-ASCII name bytes.Test plan