Hi!
On PowerPC64 PR50191 testcase when linked together with other code
results in linker crash. The problem is that a reference
to a constant pool stays in the .debug_loc section. During var-tracking
adjust_insn doesn't successfully avoid_constant_pool_reference it
because instead of a REG it uses a DEBUG_EXPR (as the register is no
longer live at that point), and rs6000_delegitimize_address checks
only for REGs in that part of the TOCREL expression. And in dwarf2out.c
we were prefering DW_OP_deref* over avoid_constant_pool_reference,
performed the latter only if mem_loc_descriptor on the address failed.
The following patch changes it to prefer avoid_constant_pool_reference.
I think we can do this in mem_loc_descriptor, because MEMs handled
by that routine are otherwise DW_OP_deref*, i.e. DWARF expression rvalues
anyway. I'm not changing loc_descriptor, because there we want to
prefer getting a REG or MEM which can be changed.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2011-09-05 Jakub Jelinek <ja...@redhat.com>
PR debug/50191
* dwarf2out.c (mem_loc_descriptor) <case MEM>: Try
avoid_constant_pool_reference first instead of last.
--- gcc/dwarf2out.c.jj 2011-07-29 17:07:20.000000000 +0200
+++ gcc/dwarf2out.c 2011-09-05 09:59:41.000000000 +0200
@@ -11695,12 +11695,22 @@ mem_loc_descriptor (rtx rtl, enum machin
break;
case MEM:
+ {
+ rtx new_rtl = avoid_constant_pool_reference (rtl);
+ if (new_rtl != rtl)
+ {
+ mem_loc_result = mem_loc_descriptor (new_rtl, mode, mem_mode,
+ initialized);
+ if (mem_loc_result != NULL)
+ return mem_loc_result;
+ }
+ }
mem_loc_result = mem_loc_descriptor (XEXP (rtl, 0),
get_address_mode (rtl), mode,
VAR_INIT_STATUS_INITIALIZED);
if (mem_loc_result == NULL)
mem_loc_result = tls_mem_loc_descriptor (rtl);
- if (mem_loc_result != 0)
+ if (mem_loc_result != NULL)
{
if (GET_MODE_SIZE (mode) > DWARF2_ADDR_SIZE
|| GET_MODE_CLASS (mode) != MODE_INT)
@@ -11728,12 +11738,6 @@ mem_loc_descriptor (rtx rtl, enum machin
new_loc_descr (DW_OP_deref_size,
GET_MODE_SIZE (mode), 0));
}
- else
- {
- rtx new_rtl = avoid_constant_pool_reference (rtl);
- if (new_rtl != rtl)
- return mem_loc_descriptor (new_rtl, mode, mem_mode, initialized);
- }
break;
case LO_SUM:
Jakub
