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qsort: dwarf2.c
This patch ensures qsort stability in line and function sorting done
in dwarf2.c. For the line sequences we make use of an existing field
that isn't used until later, as a monotonic counter for the qsort.
* dwarf2.c (struct lookup_funcinfo): Add idx field.
(compare_lookup_funcinfos): Perform final sort on idx.
(build_lookup_funcinfo_table): Set idx.
(compare_sequences): Perform final sort on num_lines.
(build_line_info_table): Set num_lines and line_info_lookup earlier.
(sort_line_sequences): Set num_lines for sort.
diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c
index 75d19aa837..c3d9ffc3c5 100644
--- a/bfd/dwarf2.c
+++ b/bfd/dwarf2.c
@@ -1413,6 +1413,8 @@ struct lookup_funcinfo
The highest address of all prior functions after the lookup table is
sorted, which is used for binary search. */
bfd_vma high_addr;
+ /* Index of this function, used to ensure qsort is stable. */
+ unsigned int idx;
};
struct varinfo
@@ -1713,6 +1715,11 @@ compare_sequences (const void* a, const void* b)
if (seq1->last_line->op_index > seq2->last_line->op_index)
return -1;
+ /* num_lines is initially an index, to make the sort stable. */
+ if (seq1->num_lines < seq2->num_lines)
+ return -1;
+ if (seq1->num_lines > seq2->num_lines)
+ return 1;
return 0;
}
@@ -1739,12 +1746,14 @@ build_line_info_table (struct line_info_table * table,
for (each_line = seq->last_line; each_line; each_line = each_line->prev_line)
num_lines++;
+ seq->num_lines = num_lines;
if (num_lines == 0)
return TRUE;
/* Allocate space for the line information lookup table. */
amt = sizeof (struct line_info*) * num_lines;
line_info_lookup = (struct line_info**) bfd_alloc (table->abfd, amt);
+ seq->line_info_lookup = line_info_lookup;
if (line_info_lookup == NULL)
return FALSE;
@@ -1754,10 +1763,6 @@ build_line_info_table (struct line_info_table * table,
line_info_lookup[--line_index] = each_line;
BFD_ASSERT (line_index == 0);
-
- seq->num_lines = num_lines;
- seq->line_info_lookup = line_info_lookup;
-
return TRUE;
}
@@ -1793,7 +1798,7 @@ sort_line_sequences (struct line_info_table* table)
sequences[n].prev_sequence = NULL;
sequences[n].last_line = seq->last_line;
sequences[n].line_info_lookup = NULL;
- sequences[n].num_lines = 0;
+ sequences[n].num_lines = n;
seq = seq->prev_sequence;
free (last_seq);
}
@@ -2569,6 +2574,10 @@ compare_lookup_funcinfos (const void * a, const void * b)
if (lookup1->high_addr > lookup2->high_addr)
return 1;
+ if (lookup1->idx < lookup2->idx)
+ return -1;
+ if (lookup1->idx > lookup2->idx)
+ return 1;
return 0;
}
@@ -2598,6 +2607,7 @@ build_lookup_funcinfo_table (struct comp_unit * unit)
{
entry = &lookup_funcinfo_table[--func_index];
entry->funcinfo = each;
+ entry->idx = func_index;
/* Calculate the lowest and highest address for this function entry. */
low_addr = entry->funcinfo->arange.low;
--
Alan Modra
Australia Development Lab, IBM