On Sun, Jul 16, 2006 at 06:05:32PM -0700, Ian Lance Taylor wrote:
> Previously, scope_labelno was referenced in dbxout_block and
> incremented in dbxout_function_end. Both functions are called only by
> dbxout_function_decl (a debug hook). So it was always consistent.
>
> Now scope_labelno is used by dbxout_begin_prologue and
> dbxout_source_line. Those are both debug hooks themselves. So this
> patch has introduced a dependency which was not previously there,
> which has led to a bug.
>
> There are several ways to fix this, of course. I think the simplest
> is going to be to always preincrement scope_labelno in
> dbxout_begin_prologue, rather than postincrementing it in
> dbxout_function_end. In cases where that fails, we are already in
> trouble.
>
> Note that scope_labelno is now used for two different things: for the
> LFBB symbol, and for the Lscope symbol. It does not have to be used
> for both, although as far as I can see it does no harm.
The following patch does a pre-increment of scope_labelno in
dbxout_begin_prologue.
No regressions on arm-none-eabi, and I verified the output stabs by
hand. The .Lscope and .LFBB labels start at 1, and increment for each
call to dbxout_begin_prologue.
Andrew, I built a powerpc-darwin cross compiler and manually verified
the output assembly from your testcase. It looks like it should fix your
problem. I don't see any repeated LFBB symbols, where previously I saw
repeated LFBB1 and LFBB4 due to the thunks.
OK to commit?
Cheers,
Carlos.
--
Carlos O'Donell
CodeSourcery
[EMAIL PROTECTED]
(650) 331-3385 x716
2006-07-17 Carlos O'Donell <[EMAIL PROTECTED]>
* dbxout.c (dbxout_function_end): Do not increment scope_labelno.
(dbxout_begin_prologue): Increment scope_labelno.
Index: gcc/dbxout.c
===================================================================
--- gcc/dbxout.c (revision 115532)
+++ gcc/dbxout.c (working copy)
@@ -905,7 +905,6 @@ static void
dbxout_function_end (tree decl)
{
char lscope_label_name[100];
- int lscope_labelno = scope_labelno++;
/* The Lscope label must be emitted even if we aren't doing anything
else; dbxout_block needs it. */
@@ -914,8 +913,8 @@ dbxout_function_end (tree decl)
/* Convert Lscope into the appropriate format for local labels in case
the system doesn't insert underscores in front of user generated
labels. */
- ASM_GENERATE_INTERNAL_LABEL (lscope_label_name, "Lscope", lscope_labelno);
- targetm.asm_out.internal_label (asm_out_file, "Lscope", lscope_labelno);
+ ASM_GENERATE_INTERNAL_LABEL (lscope_label_name, "Lscope", scope_labelno);
+ targetm.asm_out.internal_label (asm_out_file, "Lscope", scope_labelno);
/* The N_FUN tag at the end of the function is a GNU extension,
which may be undesirable, and is unnecessary if we do not have
@@ -941,7 +940,7 @@ dbxout_function_end (tree decl)
{
char begin_label[20];
/* Reference current function start using LFBB. */
- ASM_GENERATE_INTERNAL_LABEL (begin_label, "LFBB", lscope_labelno);
+ ASM_GENERATE_INTERNAL_LABEL (begin_label, "LFBB", scope_labelno);
dbxout_begin_empty_stabs (N_FUN);
dbxout_stab_value_label_diff (lscope_label_name, begin_label);
}
@@ -1249,6 +1248,9 @@ dbxout_begin_prologue (unsigned int line
&& !flag_debug_only_used_symbols)
dbxout_stabd (N_BNSYM, 0);
+ /* pre-increment the scope counter */
+ scope_labelno++;
+
dbxout_source_line (lineno, filename);
/* Output function begin block at function scope, referenced
by dbxout_block, dbxout_source_line and dbxout_function_end. */
