On Wed, 2018-08-22 at 12:48 -0700, H.J. Lu wrote: > PING. [stripping out-of-date address for Tom Tromey from recipients]
Sorry for the belated response. > ---------- Forwarded message ---------- > From: H.J. Lu <hjl.to...@gmail.com> > Date: Wed, Aug 15, 2018 at 4:33 AM > Subject: [PATCH] Set start_location to 0 if we ran out of line map > space > To: gcc-patches@gcc.gnu.org > > > With profiledbootstrap and --with-build-config=bootstrap-lto, > linemap_add > may create a macro map when we run out of line map space. This patch > changes start_location to UNKNOWN_LOCATION (0) in this case. > > Tested with profiledbootstrap and --with-build-config=bootstrap-lto > on > Linux/x86-64. > > PR bootstrap/86872 > * line-map.c (pure_location_p): Return true if linemap_lookup > returns NULL. > (linemap_add): Set start_location to 0 if we run out of line > map > space. > --- > libcpp/line-map.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/libcpp/line-map.c b/libcpp/line-map.c > index 555cd129a9c..cafe42273eb 100644 > --- a/libcpp/line-map.c > +++ b/libcpp/line-map.c > @@ -304,6 +304,8 @@ pure_location_p (line_maps *set, source_location > loc) > return false; > > const line_map *map = linemap_lookup (set, loc); > + if (map == NULL) > + return true; > const line_map_ordinary *ordmap = linemap_check_ordinary (map); I was wondering why this is needed, but it's presumably due to this clause: if (set == NULL || line < RESERVED_LOCATION_COUNT) return NULL; in linemap_ordinary_map_lookup. Normally, the ordinary_maps are monotonically increasing by start location, but with the next hunk to linemap_add there will be a map at the end for location 0 which thus isn't monotonic. > if (loc & ((1U << ordmap->m_range_bits) - 1)) > @@ -492,6 +494,11 @@ linemap_add (struct line_maps *set, enum > lc_reason reason, > } > > linemap_assert (reason != LC_ENTER_MACRO); > + > + if (start_location >= LINE_MAP_MAX_LOCATION) > + /* We ran out of line map space. */ > + start_location = 0; > + If I'm reading this right, this means that we create an ordinary map that starts at location 0. The caller, linemap_line_start should then bail out, returning location 0, and subsequent calls to linemap_line_start should return 0 without attempting to create another map. My first thought was that instead linemap_add ought to return NULL for this case, and linemap_line_start should check for NULL return and bail out, but I believe this approach would mean doing slightly more work per line. Out of interest, did you try this other approach? I wonder if there's a sane way to reproduce this failure using gcc.dg/plugin/location_overflow_plugin.c ? > line_map_ordinary *map > = linemap_check_ordinary (new_linemap (set, start_location)); > map->reason = reason; > -- > 2.17.1 Given the testing this has had, and the awkwardness of reproducing, this is OK for trunk as-is. Thanks Dave