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| author | Paul Eggert <eggert@cs.ucla.edu> | 2020-02-16 11:36:19 -0800 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2020-02-16 11:37:07 -0800 |
| commit | 556cc727e5076d590f8286406e4f46cff3cee41e (patch) | |
| tree | d23565cc5fc31bd98d2d782dcbc6cc10d5a29d9c | |
| parent | df9da9445ed665080fbcfdd25f7a544f1403cf8e (diff) | |
| download | emacs-556cc727e5076d590f8286406e4f46cff3cee41e.tar.gz | |
Improve C-h C-h bug fix
* src/lread.c (read1): Guard against two 'struct Lisp_Vector *'
pointers differing only in their most significant bit. Problem
reported by Pip Cet (Bug#39529#22).
| -rw-r--r-- | src/lread.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/src/lread.c b/src/lread.c index 1613719eb1d..70984d37e18 100644 --- a/src/lread.c +++ b/src/lread.c @@ -2982,10 +2982,13 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list) as 0. This placeholder 0 would lead to accidental sharing in purecopy's hash-consing, so replace it with a (hopefully) unique integer placeholder, which is negative so that it is - not confused with a DOC file offset. Eventually - Snarf-documentation should replace the placeholder with the - actual docstring. */ - EMACS_UINT hash = XHASH (tmp) | (INTMASK - INTMASK / 2); + not confused with a DOC file offset (the USE_LSB_TAG shift + relies on the fact that VALMASK is one bit narrower than + INTMASK). Eventually Snarf-documentation should replace the + placeholder with the actual docstring. */ + verify (INTMASK & ~VALMASK); + EMACS_UINT hash = ((XHASH (tmp) >> USE_LSB_TAG) + | (INTMASK - INTMASK / 2)); ASET (tmp, COMPILED_DOC_STRING, make_ufixnum (hash)); } |