[wip] Introduce a new line table flag is_weak
This introduces a new line table flag is_weak.
The line entries at the end of a subroutine range,
use this to indicate that they may possibly
be part of the previous subroutine.
When there is a sequence of line entries at the
same address where an inline range ends, and the
last item has is_stmt = 0, we force all previous
items to have is_weak = 1.
Additionally this adds a "fake" end sequence to the
record_line function, that is line number -1.
That will be used in the next patch.
Finally this adds a handling for empty ranges to
record_block_range. Currently this function is
not called with empty ranges, but that will be used
in the next patch.
There should be no functional changes after this commit.
Well, except the new is-weak flag in the line table of course.
As an example consider the following test code:
$ cat test.c
inline int test ()
{
asm ("nop");
return 0;
}
int main ()
{
int x = test ();
return x;
}
$ gcc -g -O2 test.c
This will receive the following line table:
(gdb) maintenance info line-table
INDEX LINE REL-ADDRESS UNREL-ADDRESS IS-STMT IS-WEAK PROLOGUE-END EPILOGUE-BEGIN
0 8 0x0000555555555040 0x0000000000001040 Y
1 9 0x0000555555555040 0x0000000000001040 Y
2 1 0x0000555555555040 0x0000000000001040 Y
3 3 0x0000555555555040 0x0000000000001040 Y
4 4 0x0000555555555041 0x0000000000001041 Y Y
5 4 0x0000555555555041 0x0000000000001041 Y <---+ set is_weak
6 10 0x0000555555555041 0x0000000000001041 Y Y ^
7 11 0x0000555555555041 0x0000000000001041 <----+ no is-stmt
8 END 0x0000555555555044 0x0000000000001044 Y
6 files changed
