Consider test-case gdb.dwarf2/dw2-ranges-base.exp. It has (ignoring
non-sensical entries that are filtered out by buildsym_compunit::record_line)
a line-table for dw2-ranges-base.c like this:
...
Line Number Statements:
[0x0000014e] Extended opcode 2: set Address to 0x4004ba
[0x00000159] Advance Line by 10 to 11
[0x0000015b] Copy
[0x0000015c] Advance PC by 12 to 0x4004c6
[0x0000015e] Extended opcode 1: End of Sequence
[0x00000161] Extended opcode 2: set Address to 0x4004ae
[0x0000016c] Advance Line by 20 to 21
[0x0000016e] Copy
[0x0000016f] Advance PC by 12 to 0x4004ba
[0x00000171] Extended opcode 1: End of Sequence
[0x00000174] Extended opcode 2: set Address to 0x4004a7
[0x0000017f] Advance Line by 30 to 31
[0x00000181] Copy
[0x00000182] Advance PC by 7 to 0x4004ae
[0x00000184] Extended opcode 1: End of Sequence
...
If we disable the sorting in buildsym_compunit::end_symtab_with_blockvector,
we have the unsorted line table:
...
INDEX LINE ADDRESS IS-STMT
0 11 0x00000000004004ba Y
1 END 0x00000000004004c6 Y
2 21 0x00000000004004ae Y
3 END 0x00000000004004ba Y
4 31 0x00000000004004a7 Y
5 END 0x00000000004004ae Y
...
It contains 3 sequences, 11/END, 21/END and 31/END.
We want to sort the 3 sequences relative to each other, while sorting on
address, to get:
...
INDEX LINE ADDRESS IS-STMT
0 31 0x00000000004004a7 Y
1 END 0x00000000004004ae Y
2 21 0x00000000004004ae Y
3 END 0x00000000004004ba Y
4 11 0x00000000004004ba Y
5 END 0x00000000004004c6 Y
...
However, if we re-enable the sorting, we have instead:
...
INDEX LINE ADDRESS IS-STMT
0 31 0x00000000004004a7 Y
1 21 0x00000000004004ae Y
2 END 0x00000000004004ae Y
3 11 0x00000000004004ba Y
4 END 0x00000000004004ba Y
5 END 0x00000000004004c6 Y
...
This is a regression since commit 3d92a3e313 "gdb: Don't reorder line table
entries too much when sorting", that introduced sorting on address while
keeping entries with the same address in pre-sort order.
Indeed the entries 1 and 2 are in pre-sort order (they map to entries 2 and 5
in the unsorted line table), but entry 1 does not belong in the sequence
terminated by 2.
Fix this by handling End-Of-Sequence entries in the sorting function, such
that they are sorted before other entries with the same address.
Also, revert the find_pc_sect_line workaround introduced in commit 3d92a3e313,
since that's no longer necessary.
Tested on x86_64-linux.
gdb/ChangeLog:
2020-07-06 Tom de Vries <tdevries@suse.de>
* buildsym.c (buildsym_compunit::end_symtab_with_blockvector): Handle
End-Of-Sequence in lte_is_less_than.
* symtab.c (find_pc_sect_line): Revert change from commit 3d92a3e313
"gdb: Don't reorder line table entries too much when sorting".
gdb/testsuite/ChangeLog:
2020-07-06 Tom de Vries <tdevries@suse.de>
* gdb.dwarf2/dw2-ranges-base.exp: Test line-table order.
