Mercurial > cpython-lru_cache-weakref
diff Python/compile.c @ 34626:fcacf9d4b8f0 legacy-trunk
Document how the pattern recognizer keeps all of its references in bounds.
Add a test in case the underlying assumptions ever change (i.e. the
compiler starts generating code blocks that are not punctuated by
RETURN_VALUE).
| author | Raymond Hettinger <python@rcn.com> |
|---|---|
| date | Mon, 21 Feb 2005 20:03:14 +0000 |
| parents | 516bb8fd75b4 |
| children | 660419bdb4ae |
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--- a/Python/compile.c Mon Feb 21 15:46:52 2005 +0000 +++ b/Python/compile.c Mon Feb 21 20:03:14 2005 +0000 @@ -677,6 +677,14 @@ goto exitUnchanged; codestr = memcpy(codestr, PyString_AS_STRING(code), codelen); + /* Verify that RETURN_VALUE terminates the codestring. This allows + the various transformation patterns to look ahead several + instructions without additional checks to make sure they are not + looking beyond the end of the code string. + */ + if (codestr[codelen-1] != RETURN_VALUE) + goto exitUnchanged; + /* Mapping to new jump targets after NOPs are removed */ addrmap = PyMem_Malloc(codelen * sizeof(int)); if (addrmap == NULL)