Re: PING^1: [PATCH] Set start_location to 0 if we ran out of line map space
On Fri, Aug 24, 2018 at 4:05 PM, David Malcolm wrote:
> 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 [stripping out-of-date address for Tom Tromey from recipients]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
>> 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.
and
/* Any ordinary locations ought to be "pure" at this point: no
compressed ranges. */
linemap_assert (locus < RESERVED_LOCATION_COUNT
|| locus >= LINE_MAP_MAX_LOCATION_WITH_PACKED_RANGES
|| locus >= LINEMAPS_MACRO_LOWEST_LOCATION (set)
|| pure_location_p (set, locus));
/* Consider short-range optimization. */
if (can_be_stored_compactly_p (set, locus, src_range, data))
{
/* The low bits ought to be clear. */
linemap_assert (pure_location_p (set, locus));
> 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?
Yes, I did. But it didn't work since callers of inemap_add expect
non-NULL return value for this case.
> 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
>
I will check it in.
Thanks.
--
H.J.
Re: PING^1: [PATCH] Set start_location to 0 if we ran out of line map space
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 > 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
PING^1: [PATCH] Set start_location to 0 if we ran out of line map space
PING. -- Forwarded message -- From: H.J. Lu 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); 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; + line_map_ordinary *map = linemap_check_ordinary (new_linemap (set, start_location)); map->reason = reason; -- 2.17.1 -- H.J.
