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| author | David Malcolm <dmalcolm@redhat.com> | 2017-01-10 21:54:09 +0000 |
|---|---|---|
| committer | David Malcolm <dmalcolm@gcc.gnu.org> | 2017-01-10 21:54:09 +0000 |
| commit | b9f4757f8eb94d4b145613ee5047f3f95452f9d2 (patch) | |
| tree | 4f329935d56c10c19a73497a7006a9a709292f4f /gcc/cp | |
| 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 'gcc/cp')
| -rw-r--r-- | gcc/cp/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/cp/parser.c | 5 |
2 files changed, 11 insertions, 1 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 25f5a85..892651a 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,10 @@ +2017-01-10 David Malcolm <dmalcolm@redhat.com> + + 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. + 2017-01-10 Jason Merrill <jason@redhat.com> FI 20, decomposition declaration with parenthesized initializer. diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index 4517313..7b3ee30 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -22164,7 +22164,10 @@ cp_parser_class_specifier_1 (cp_parser* parser) next_loc = linemap_position_for_loc_and_offset (line_table, loc, 1); rich_location richloc (line_table, next_loc); - richloc.add_fixit_insert_before (next_loc, ";"); + + /* If we successfully offset the location, suggest the fix-it. */ + if (next_loc != loc) + richloc.add_fixit_insert_before (next_loc, ";"); if (CLASSTYPE_DECLARED_CLASS (type)) error_at_rich_loc (&richloc, |