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Re: [line-map patch] Better packing of maps
On 06/26/2018 03:31 PM, David Malcolm wrote:
Which assert are you referring to?
Hm, I think I may have been confused by the unsigned arithmetic check in:
if (start_location <= set->highest_line
|| start_location > LINEMAPS_MACRO_LOWEST_LOCATION (set))
/* We ran out of macro map space. */
return NULL;
It looks to me that the second condition can only be true with the first
being false when the macro expansion is >= 2^32 tokens (give or take).
However, AFAICT, linemap_add doesn't check whether ordinary maps have
run into the macro range:
if (set->highest_location < LINE_MAP_MAX_LOCATION_WITH_COLS)
{...}
else
start_location = set->highest_location + 1;
So if I'm reading the patch correctly, it introduces a new limit on how
big the macro maps can be: 0x10000000, hence about 268 million macro
argument expansions, I believe, before it will stop tracking macro
expansions.
You may be correct. The comment in line-map.h is unclear as to whether
the LINE_MAP_MAX_SOURCE_LOCATION is a barrier for macros or not, it can
be read either way.
Has this been smoketested on some very large C++ TUs?
No. The code bases available to me aren't gcc-trunk ready (I don't know
if they contain single TUs so large).
nathan
--
Nathan Sidwell