[Bug c++/77949] [7 Regression] ICE on invalid code in internal compiler error: in linemap_position_for_loc_and_offset, at libcpp/line-map.c:907

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77949

David Malcolm  changed:

   What|Removed |Added

 Status|ASSIGNED|RESOLVED
 Resolution|--- |FIXED

--- Comment #5 from David Malcolm  ---
Should be fixed by r244292; closing.

[Bug c++/77949] [7 Regression] ICE on invalid code in internal compiler error: in linemap_position_for_loc_and_offset, at libcpp/line-map.c:907

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77949

--- Comment #4 from David Malcolm  ---
Author: dmalcolm
Date: Tue Jan 10 21:54:09 2017
New Revision: 244292

URL: https://gcc.gnu.org/viewcvs?rev=244292=gcc=rev
Log:
Fix issues with unrepresentable column numbers (PR c++/77949)

PR c++/77949 identifies an ICE when the C++ frontend attempts to emit a
fix-it hint inserting a missing semicolon at column 4097 of a source file.

This column value exceeds LINE_MAP_MAX_COLUMN_NUMBER and hence isn't
representable using a location_t.

Attempting to do so leads to these problems, which this patch fixes:

(a) when encountering a column number > LINE_MAP_MAX_COLUMN_NUMBER we
create a new linemap with m_column_and_range_bits == 0, but
linemap_position_for_column doesn't check for this, and hence can emit
a bogus location_t value that's calculated relative to the previous
linemap start, but which will be decoded relative to the new linemap,
leading to very large incorrect line values.

(b) when encountering a column number that can't be represented, and
for which the linemap was pre-existing, the code would hit this assertion:
  if (linemap_assert_fails (column < (1u << map->m_column_and_range_bits)))
around a bail-out condition.  The patch replaces this assertion with a
simple conditional, to stop the ICE when this occurs, and fixes the
bit count (effective column bits, vs column+range bits)

(c) the C++ frontend wasn't checking for failure of
linemap_position_for_loc_and_offset when considering emitting the fix-it
hint.  The patch adds a conditional, so that no fix-it hint is emitted
if the location is bogus.

gcc/cp/ChangeLog:
PR c++/77949
* parser.c (cp_parser_class_specifier_1): Only suggest inserting
a missing semicolon if we have a valid insertion location for
the fix-it hint.

gcc/ChangeLog:
PR c++/77949
* input.c (selftest::test_accessing_ordinary_linemaps): Verify
that we correctly handle column numbers greater than
LINE_MAP_MAX_COLUMN_NUMBER.

gcc/testsuite/ChangeLog:
PR c++/77949
* g++.dg/diagnostic/pr77949.C: New test case.

libcpp/ChangeLog:
PR c++/77949
* line-map.c (linemap_position_for_column): When calling
linemap_start_line, detect if a new linemap was created with
0 column bits, and bail out early if this is the case.
(linemap_position_for_loc_and_offset): Replace overzealous
linemap_assert_fails with a simple conditional; use correct
bit count.


Added:
trunk/gcc/testsuite/g++.dg/diagnostic/pr77949.C
Modified:
trunk/gcc/ChangeLog
trunk/gcc/cp/ChangeLog
trunk/gcc/cp/parser.c
trunk/gcc/input.c
trunk/gcc/testsuite/ChangeLog
trunk/libcpp/ChangeLog
trunk/libcpp/line-map.c

[Bug c++/77949] [7 Regression] ICE on invalid code in internal compiler error: in linemap_position_for_loc_and_offset, at libcpp/line-map.c:907

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77949

David Malcolm  changed:

   What|Removed |Added

 Status|NEW |ASSIGNED
   Assignee|aldyh at gcc dot gnu.org   |dmalcolm at gcc dot 
gnu.org

[Bug c++/77949] [7 Regression] ICE on invalid code in internal compiler error: in linemap_position_for_loc_and_offset, at libcpp/line-map.c:907

[aldyh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77949

--- Comment #3 from Aldy Hernandez  ---
Caused by:

commit b65b8df248d4eb4801cbe16287cf32eda9325dec
Author: dmalcolm 
Date:   Tue Jul 5 15:50:54 2016 +

PR c++/62314: add fixit hint for "expected ';' after class definition"

gcc/cp/ChangeLog:
PR c++/62314
* parser.c (cp_parser_class_specifier_1): When reporting
missing semicolons, use a fixit-hint to suggest insertion
of a semicolon immediately after the closing brace,
offsetting the reported column accordingly.

gcc/testsuite/ChangeLog:
PR c++/62314
* gcc/testsuite/g++.dg/parse/error5.C: Update column
number of missing semicolon error.
* g++.dg/pr62314-2.C: New test case.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@238008
138bc75d-0d04-0410-96
1f-82ee72b054a4

[Bug c++/77949] [7 Regression] ICE on invalid code in internal compiler error: in linemap_position_for_loc_and_offset, at libcpp/line-map.c:907

[aldyh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77949

Aldy Hernandez  changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
   Last reconfirmed||2016-11-04
 CC||aldyh at gcc dot gnu.org
   Assignee|unassigned at gcc dot gnu.org  |aldyh at gcc dot gnu.org
 Ever confirmed|0   |1

--- Comment #2 from Aldy Hernandez  ---
Confirmed.  I'll take a peek.

[Bug c++/77949] [7 Regression] ICE on invalid code in internal compiler error: in linemap_position_for_loc_and_offset, at libcpp/line-map.c:907

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77949

Richard Biener  changed:

   What|Removed |Added

   Target Milestone|--- |7.0

[Bug c++/77949] [7 Regression] ICE on invalid code in internal compiler error: in linemap_position_for_loc_and_offset, at libcpp/line-map.c:907

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77949

--- Comment #1 from Martin Liška  ---
Created attachment 39792
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39792=edit
Test-case