Hi!
This patch fixes both a correctness problem (bootstrap failure in
libgfortran for a couple of targets) and debug info quality issue.
The correctness issue is about the fact that clearing DECL_INITIAL
(well, setting it to error_mark_node is the same) in varpool_remove_node
is changing the decl's bss_initializer_p (decl) status, thus can affect
section flags of it for DWARF2 if an unused decl has
e.g. make_decl_rtl_for_debug called from implicit pointer expansion
before varpool_remove_node and then e.g. during dwarf2out_finish after it.
This function intentionally doesn't remember the RTL, that could affect
code generation.
And for the debug info quality issue see the next patch that actually
improves use of DECL_INITIAL for debug info generation.
Even if we add some param to limit the size of the initializers we want to
emit into debug info, still the varpool_remove_node clearing of the
initializer would need to be done (if we want to try hard to save compile
time memory) in a way to keep the bss_initializer_p the same as before,
so call it before clearing, if it was set, setting it to error_mark_node
is perhaps fine, if it was set, it needs to be set to some other magic
value and everything that uses DECL_INITIAL afterwards need to be taught
about that (including bss_initializer_p not to treat that other magic value
as bss initializer).
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2012-12-06 Jakub Jelinek <ja...@redhat.com>
PR fortran/55395
* varpool.c (varpool_remove_node): Don't drop DECL_INITIAL
if -g and emitting DWARF2+.
--- gcc/varpool.c.jj 2012-11-19 14:41:27.000000000 +0100
+++ gcc/varpool.c 2012-12-04 17:42:41.228752645 +0100
@@ -65,7 +65,10 @@ varpool_remove_node (struct varpool_node
&& !DECL_VIRTUAL_P (node->symbol.decl)
/* dbxout output constant initializers for readonly vars. */
&& (!host_integerp (DECL_INITIAL (node->symbol.decl), 0)
- || !TREE_READONLY (node->symbol.decl)))
+ || !TREE_READONLY (node->symbol.decl))
+ /* dwarf2out can use most of the initializers. */
+ && write_symbols != DWARF2_DEBUG
+ && write_symbols != VMS_AND_DWARF2_DEBUG)
DECL_INITIAL (node->symbol.decl) = error_mark_node;
ggc_free (node);
}
Jakub
