On 06/07/2015 02:33 PM, Richard Biener wrote:
On June 7, 2015 6:00:05 PM GMT+02:00, Aldy Hernandez <al...@redhat.com> wrote:
On 06/07/2015 11:25 AM, Richard Biener wrote:
On June 7, 2015 5:03:30 PM GMT+02:00, Aldy Hernandez
<al...@redhat.com> wrote:
On 06/06/2015 05:49 AM, Andreas Schwab wrote:
Bootstrap fails on aarch64:
Comparing stages 2 and 3
warning: gcc/cc1objplus-checksum.o differs
warning: gcc/cc1obj-checksum.o differs
warning: gcc/cc1plus-checksum.o differs
warning: gcc/cc1-checksum.o differs
Bootstrap comparison failure!
gcc/ira-costs.o differs
gcc/tree-sra.o differs
gcc/tree-parloops.o differs
gcc/tree-vect-data-refs.o differs
gcc/java/jcf-io.o differs
gcc/ipa-inline-analysis.o differs
The bootstrap comparison failure on ppc64le, aarch64, and possibly
others is due to the order of some sections being in a different
order
with and without debugging.
Stage2 is being compiled with no debugging due to -gtoggle, and
stage3
is being compiled with debugging.
For ira-costs.o on ppc64le we have:
-Disassembly of section
.rodata._ZN10hash_tableI19cost_classes_hasher11xcallocatorE6expandEv.str1.8:
+Disassembly of section
.rodata._ZN10hash_tableI19cost_classes_hasher11xcallocatorE26find_empty_slot_for_expandEj.str1.8:
...
-Disassembly of section
.rodata._ZN10hash_tableI19cost_classes_hasher11xcallocatorE26find_empty_slot_for_expandEj.str1.8:
+Disassembly of section
.rodata._ZN10hash_tableI19cost_classes_hasher11xcallocatorE6expandEv.str1.8:
There is no semantic difference between the objects, just the
ordering.
I assume it's the same problem for the rest of the objects and
architectures.
I will look into this, unless someone beats me to it, or has an idea
right off the bat.
Check whether the symbol table walkers are walking hash tables. I
assume the above are emitted via the symbol removal handling for debug
stuff?
Ughh, indeed. These sections are being outputted from
output_object_blocks which traverses a hash table:
void
output_object_blocks (void)
{
object_block_htab->traverse<void *, output_object_block_htab> (NULL);
}
Perhaps we should sort them by some deterministic field and then call
output_object_block() on each member of the resulting list?
Yes, that would be the usual fix. Maybe sth has an UID already, is the 'object'
a decl by chance?
The attached patch fixes the bootstrap failure on ppc64le, and
theoretically the aarch64 problem as well, but I haven't checked.
Tested on ppc64le linux by bootstrapping, and regtesting C/C++ against
pre debug-early merge sources. Also tested by a full bootstrap and
regtest on x86-64 Linux.
OK for mainline?
Aldy
* varasm.c (output_object_block_htab): Push each object_block into
a vector instead of calling output_object_block.
(output_object_block_compare): New.
(output_object_blocks): Sort object_blocks and then output them.
diff --git a/gcc/varasm.c b/gcc/varasm.c
index 18f3eac..008360e 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -7420,22 +7420,57 @@ output_object_block (struct object_block *block)
}
}
-/* A htab_traverse callback used to call output_object_block for
- each member of object_block_htab. */
+/* An htab_traverse callback used to copy object_blocks into a vector. */
int
-output_object_block_htab (object_block **slot, void *)
+output_object_block_htab (object_block **slot, void *data)
{
- output_object_block (*slot);
+ vec<object_block *, va_heap> *v = (vec<object_block *, va_heap> *) data;
+ v->safe_push (*slot);
return 1;
}
+/* A callback for qsort to compare object_blocks. We only care about
+ named sections. */
+
+static int
+output_object_block_compare (const void *x, const void *y)
+{
+ object_block *p1 = *(object_block * const*)x;
+ object_block *p2 = *(object_block * const*)y;
+
+ if (p1->sect->common.flags & SECTION_NAMED
+ && !(p2->sect->common.flags & SECTION_NAMED))
+ return 1;
+
+ if (!(p1->sect->common.flags & SECTION_NAMED)
+ && p2->sect->common.flags & SECTION_NAMED)
+ return -1;
+
+ if (p1->sect->common.flags & SECTION_NAMED
+ && p2->sect->common.flags & SECTION_NAMED)
+ return strcmp (p1->sect->named.name,
+ p2->sect->named.name);
+
+ return 0;
+}
+
/* Output the definitions of all object_blocks. */
void
output_object_blocks (void)
{
- object_block_htab->traverse<void *, output_object_block_htab> (NULL);
+ vec<object_block *, va_heap> v = vNULL;
+ object_block_htab->traverse<void *, output_object_block_htab> (&v);
+
+ /* Sort them in order to output them in a deterministic manner,
+ otherwise we may get .rodata sections in different orders with
+ and without -g. */
+ v.qsort (output_object_block_compare);
+ unsigned i;
+ object_block *obj;
+ FOR_EACH_VEC_ELT (v, i, obj)
+ output_object_block (obj);
}
/* This function provides a possible implementation of the
