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author | David Malcolm <dmalcolm@redhat.com> | 2017-01-10 21:54:09 +0000 |
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committer | David Malcolm <dmalcolm@gcc.gnu.org> | 2017-01-10 21:54:09 +0000 |
commit | b9f4757f8eb94d4b145613ee5047f3f95452f9d2 (patch) | |
tree | 4f329935d56c10c19a73497a7006a9a709292f4f /libcpp | |
parent | 6fcb740ac456e4703b337584b26305a77a5c5038 (diff) | |
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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.
From-SVN: r244292
Diffstat (limited to 'libcpp')
-rw-r--r-- | libcpp/ChangeLog | 10 | ||||
-rw-r--r-- | libcpp/line-map.c | 19 |
2 files changed, 28 insertions, 1 deletions
diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog index 082291d..208e1d5 100644 --- a/libcpp/ChangeLog +++ b/libcpp/ChangeLog @@ -1,3 +1,13 @@ +2017-01-10 David Malcolm <dmalcolm@redhat.com> + + 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. + 2017-01-07 David Malcolm <dmalcolm@redhat.com> PR c++/72803 diff --git a/libcpp/line-map.c b/libcpp/line-map.c index b410c00..949489e 100644 --- a/libcpp/line-map.c +++ b/libcpp/line-map.c @@ -816,8 +816,22 @@ linemap_position_for_column (struct line_maps *set, unsigned int to_column) } else { + /* Otherwise, attempt to start a new line that can hold TO_COLUMN, + with some space to spare. This may or may not lead to a new + linemap being created. */ line_map_ordinary *map = LINEMAPS_LAST_ORDINARY_MAP (set); r = linemap_line_start (set, SOURCE_LINE (map, r), to_column + 50); + map = LINEMAPS_LAST_ORDINARY_MAP (set); + if (map->m_column_and_range_bits == 0) + { + /* ...then the linemap has column-tracking disabled, + presumably due to exceeding either + LINE_MAP_MAX_LOCATION_WITH_COLS (overall) or + LINE_MAP_MAX_COLUMN_NUMBER (within this line). + Return the start of the linemap, which encodes column 0, for + the whole line. */ + return r; + } } } line_map_ordinary *map = LINEMAPS_LAST_ORDINARY_MAP (set); @@ -905,7 +919,10 @@ linemap_position_for_loc_and_offset (struct line_maps *set, } column += column_offset; - if (linemap_assert_fails (column < (1u << map->m_column_and_range_bits))) + + /* Bail out if the column is not representable within the existing + linemap. */ + if (column >= (1u << (map->m_column_and_range_bits - map->m_range_bits))) return loc; source_location r = |