On Wed, Jul 3, 2013 at 11:25 AM, Cary Coutant <ccout...@google.com> wrote:
>
> > - locus = location_with_discriminator (
> > - locus, next_discriminator_for_locus (locus));
> > + discriminator = next_discriminator_for_locus (locus);
> >
> > - if (block != NULL)
> > - locus = COMBINE_LOCATION_DATA (line_table, locus, block);
> > -
> > for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
> > {
> > gimple stmt = gsi_stmt (gsi);
> > - if (same_line_p (locus, gimple_location (stmt)))
> > - gimple_set_location (stmt, locus);
> > + location_t stmt_locus = gimple_location (stmt);
> > + if (same_line_p (locus, stmt_locus))
> > + gimple_set_location (
> > + stmt, location_with_discriminator (stmt_locus, discriminator));
> > }
> > }
>
> Sorry, this may be right, but I'm not yet convinced. Check my reasoning here:
>
> So we're back to same_line_p returns true if the two loci have the
> same spelling point, right? We're looping through the gimple stmts in
We actually change to expand_location instead, patch updated.
> the bb, looking for stmts that have the same spelling point, then
> assigning a new locus using that discriminator. Since the
> discriminator is associated with the spelling point, this won't be
> using one discriminator for different lines, but you may need to
> create a new locus in case the spelling point is the same but the
> expansion point is different. But location_with_discriminator is going
> to allocate a new locus unconditionally, so this will create a new
> locus for each stmt in the bb, even if they have the same locus to
> begin with. On large programs, I be afraid that this may exhaust the
> available supply of location_t values.
>
> How about saving the original locus and checking for straightforward
> equality first? If the stmt's locus is equal to the starting one, then
> just set it to the new locus; otherwise, check for same_line_p and
> create a new locus if that returns true. Something like this
> (untested):
>
> assign_discriminator (location_t locus, basic_block bb)
> {
> gimple_stmt_iterator gsi;
> int discriminator;
> location_t new_locus;
>
> locus = map_discriminator_location (locus);
>
> if (locus == UNKNOWN_LOCATION)
> return;
>
> discriminator = next_discriminator_for_locus (locus);
> new_locus = location_with_discriminator (locus, discriminator)
>
> for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
> {
> gimple stmt = gsi_stmt (gsi);
> location_t stmt_locus = gimple_location (stmt);
>
> if (locus == stmt_locus)
> gimple_set_location (stmt, new_locus);
> else if (same_line_p (locus, stmt_locus))
> gimple_set_location (
> stmt, location_with_discriminator (stmt_locus, discriminator));
> }
> }
>
> This could still allocate lots of unnecessary new location_t values,
> though (and may never use new_locus). Maybe the right thing to do
> would be to have location_with_discriminator implement a rudimentary
> cache to avoid handing out a new location_t value when a
> recently-allocated one matches. (I don't think you even need a cache
> -- it can just look back at the last few elements in
> discriminator_location_locations and
> discriminator_location_discriminators.)
You are right. I've updated the patch to do this. Testing on-going.
Index: gcc/input.c
===================================================================
--- gcc/input.c (revision 200643)
+++ gcc/input.c (working copy)
@@ -308,7 +308,8 @@ location_with_discriminator (location_t locus, int
{
tree block = LOCATION_BLOCK (locus);
location_t ret;
- locus = LOCATION_LOCUS (locus);
+ int i;
+ locus = map_discriminator_location (locus);
if (locus == UNKNOWN_LOCATION)
return block ? COMBINE_LOCATION_DATA (line_table, locus, block)
@@ -320,14 +321,23 @@ location_with_discriminator (location_t locus, int
next_discriminator_location = min_discriminator_location;
}
+ /* Traverse the last few discriminator_locations to see if we can reuse
+ the entry. */
+ for (i = next_discriminator_location - min_discriminator_location - 1;
+ i >= 0 && LOCATION_LINE (discriminator_location_locations[i]) ==
+ LOCATION_LINE (locus) &&
+ discriminator_location_discriminators[i] == discriminator; i--)
+ if (discriminator_location_locations[i] == locus)
+ return block ? next_discriminator_location - i :
+ COMBINE_LOCATION_DATA (line_table, next_discriminator_location - i,
+ block);
+
discriminator_location_locations.safe_push(locus);
discriminator_location_discriminators.safe_push(discriminator);
- if (block != NULL)
- ret = COMBINE_LOCATION_DATA (line_table, next_discriminator_location,
- block);
- else
- ret = next_discriminator_location;
+ ret = block ? next_discriminator_location :
+ COMBINE_LOCATION_DATA (line_table, next_discriminator_location,
+ block);
next_discriminator_location++;
return ret;
}
Index: gcc/tree-cfg.c
===================================================================
--- gcc/tree-cfg.c (revision 200643)
+++ gcc/tree-cfg.c (working copy)
@@ -732,8 +732,8 @@ same_line_p (location_t locus1, location_t locus2)
if (locus1 == locus2)
return true;
- from = expand_location_to_spelling_point (locus1);
- to = expand_location_to_spelling_point (locus2);
+ from = expand_location (locus1);
+ to = expand_location (locus2);
if (from.line != to.line)
return false;
@@ -751,24 +751,22 @@ static void
assign_discriminator (location_t locus, basic_block bb)
{
gimple_stmt_iterator gsi;
- tree block = LOCATION_BLOCK (locus);
+ int discriminator;
locus = map_discriminator_location (locus);
if (locus == UNKNOWN_LOCATION)
return;
- locus = location_with_discriminator (
- locus, next_discriminator_for_locus (locus));
+ discriminator = next_discriminator_for_locus (locus);
- if (block != NULL)
- locus = COMBINE_LOCATION_DATA (line_table, locus, block);
-
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
gimple stmt = gsi_stmt (gsi);
- if (same_line_p (locus, gimple_location (stmt)))
- gimple_set_location (stmt, locus);
+ location_t stmt_locus = gimple_location (stmt);
+ if (same_line_p (locus, stmt_locus))
+ gimple_set_location (
+ stmt, location_with_discriminator (stmt_locus, discriminator));
}
}
Thanks,
Dehao
>
> -cary
