diff options
Diffstat (limited to 'src/lread.c')
| -rw-r--r-- | src/lread.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/src/lread.c b/src/lread.c index 10eec3b1be0..58d518ce40b 100644 --- a/src/lread.c +++ b/src/lread.c @@ -2917,7 +2917,18 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list) if (c == '=') { /* Make a placeholder for #n# to use temporarily. */ - AUTO_CONS (placeholder, Qnil, Qnil); + /* Note: We used to use AUTO_CONS to allocate + placeholder, but that is a bad idea, since it + will place a stack-allocated cons cell into + the list in read_objects, which is a + staticpro'd global variable, and thus each of + its elements is marked during each GC. A + stack-allocated object will become garbled + when its stack slot goes out of scope, and + some other function reuses it for entirely + different purposes, which will cause crashes + in GC. */ + Lisp_Object placeholder = Fcons (Qnil, Qnil); Lisp_Object cell = Fcons (make_number (n), placeholder); read_objects = Fcons (cell, read_objects); |