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Fix an undefined behavior in record_line

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Additionally do not completely remove symbols
at the same PC than the end marker, instead
make them non-is-stmt breakpoints.

2020-04-01  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* buildsym.c (record_line): Fix undefined behavior and preserve
	lines at eof.
This commit is contained in:
Bernd Edlinger 2020-03-12 11:52:34 +01:00
parent bbe3dc410b
commit 64dc2d4bd2
2 changed files with 23 additions and 16 deletions
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5
gdb/ChangeLog
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@ -1,3 +1,8 @@
2020-04-01 Bernd Edlinger <bernd.edlinger@hotmail.de>
* buildsym.c (record_line): Fix undefined behavior and preserve
lines at eof.
2020-04-01 Bernd Edlinger <bernd.edlinger@hotmail.de>
* buildsym.c (record_line): Fix the resizing condition.

34
gdb/buildsym.c
View File

@ -705,27 +705,29 @@ buildsym_compunit::record_line (struct subfile *subfile, int line,
* sizeof (struct linetable_entry))));
}
/* Normally, we treat lines as unsorted. But the end of sequence
marker is special. We sort line markers at the same PC by line
number, so end of sequence markers (which have line == 0) appear
first. This is right if the marker ends the previous function,
and there is no padding before the next function. But it is
wrong if the previous line was empty and we are now marking a
switch to a different subfile. We must leave the end of sequence
marker at the end of this group of lines, not sort the empty line
to after the marker. The easiest way to accomplish this is to
delete any empty lines from our table, if they are followed by
end of sequence markers. All we lose is the ability to set
breakpoints at some lines which contain no instructions
anyway. */
/* The end of sequence marker is special. We need to reset the
is_stmt flag on previous lines at the same PC, otherwise these
lines may cause problems since they might be at the same address
as the following function. For instance suppose a function calls
abort there is no reason to emit a ret after that point (no joke).
So the label may be at the same address where the following
function begins. A similar problem appears if a label is at the
same address where an inline function ends we cannot reliably tell
if this is considered part of the inline function or the calling
program or even the next inline function, so stack traces may
give surprising results. Expect gdb.cp/step-and-next-inline.exp
to fail if these lines are not modified here. */
if (line == 0 && subfile->line_vector->nitems > 0)
{
e = subfile->line_vector->item + subfile->line_vector->nitems - 1;
while (subfile->line_vector->nitems > 0 && e->pc == pc)
e = subfile->line_vector->item + subfile->line_vector->nitems;
do
{
e--;
subfile->line_vector->nitems--;
if (e->pc != pc || e->line == 0)
break;
e->is_stmt = 0;
}
while (e > subfile->line_vector->item);
}
e = subfile->line_vector->item + subfile->line_vector->nitems++;