Fix LTO parameter sharing

Fix LTO parameter sharing

[Jan Hubicka]

Hi,
this is Richi's patch fixing importantbug in LTO ipa-cp.  At moment we read in
summaries first and then when reading function bodies, we change parameter
lists.  This cause IPA-CP to create clones but not really propagate anything
into them. Also we get ICE with enable-checking compiler in SPEC gzip since the
unshared params get garbage collected.

I've bootstrapped/regtested patch on x86_64-linux and intend to check it in shortly.

Honza

	* lto-streamer-out.c (output_function): Output head of argument list
	earlier.
	* lto-streamer-in.c (input_function): Re-map arguments into merged
	declaration.
Index: lto-streamer-out.c
===================================================================
*** lto-streamer-out.c	(revision 154095)
--- lto-streamer-out.c	(working copy)
*************** output_function (struct cgraph_node *nod
*** 1870,1875 ****
--- 1870,1878 ----
    /* Output all the local variables in the function.  */
    lto_output_tree_ref (ob, fn->local_decls);
  
+   /* Output the head of the arguments list.  */
+   lto_output_tree_ref (ob, DECL_ARGUMENTS (function));
+ 
    /* Output all the SSA names used in the function.  */
    output_ssa_names (ob, fn);
  
*************** output_function (struct cgraph_node *nod
*** 1880,1888 ****
       lexical scopes.  */
    lto_output_tree (ob, DECL_INITIAL (function), true);
  
-   /* Output the head of the arguments list.  */
-   lto_output_tree_ref (ob, DECL_ARGUMENTS (function));
- 
    /* We will renumber the statements.  The code that does this uses
       the same ordering that we use for serializing them so we can use
       the same code on the other end and not have to write out the
--- 1883,1888 ----
Index: lto-streamer-in.c
===================================================================
*** lto-streamer-in.c	(revision 154095)
--- lto-streamer-in.c	(working copy)
*************** input_function (tree fn_decl, struct dat
*** 1262,1267 ****
--- 1262,1268 ----
    basic_block bb;
    struct bitpack_d *bp;
    struct cgraph_node *node;
+   tree args, narg, oarg;
  
    fn = DECL_STRUCT_FUNCTION (fn_decl);
    tag = input_record_start (ib);
*************** input_function (tree fn_decl, struct dat
*** 1296,1301 ****
--- 1297,1318 ----
    /* Read all the local symbols.  */
    fn->local_decls = lto_input_tree (ib, data_in);
  
+   /* Read all function arguments.  We need to re-map them here to the
+      arguments of the merged function declaration.  */
+   args = lto_input_tree (ib, data_in); 
+   for (oarg = args, narg = DECL_ARGUMENTS (fn_decl);
+        oarg && narg;
+        oarg = TREE_CHAIN (oarg), narg = TREE_CHAIN (narg))
+     {
+       int ix;
+       bool res;
+       res = lto_streamer_cache_lookup (data_in->reader_cache, oarg, &ix);
+       gcc_assert (res);
+       /* Replace the argument in the streamer cache.  */
+       lto_streamer_cache_insert_at (data_in->reader_cache, narg, ix);
+     }
+   gcc_assert (!oarg && !narg);
+ 
    /* Read all the SSA names.  */
    input_ssa_names (ib, data_in, fn);
  
*************** input_function (tree fn_decl, struct dat
*** 1307,1315 ****
    gcc_assert (DECL_INITIAL (fn_decl));
    DECL_SAVED_TREE (fn_decl) = NULL_TREE;
  
-   /* Read all function arguments.  */
-   DECL_ARGUMENTS (fn_decl) = lto_input_tree (ib, data_in); 
- 
    /* Read all the basic blocks.  */
    tag = input_record_start (ib);
    while (tag)
--- 1324,1329 ----

Re: Fix LTO parameter sharing

[Diego Novillo]

On Wed, Nov 11, 2009 at 15:20, Jan Hubicka <hubicka@ucw.cz> wrote:

> I've bootstrapped/regtested patch on x86_64-linux and intend to check it in shortly.

Nit: You actually need a review for these kinds of changes.

>
> Honza
>
>        * lto-streamer-out.c (output_function): Output head of argument list
>        earlier.
>        * lto-streamer-in.c (input_function): Re-map arguments into merged
>        declaration.

OK.


Diego.

Re: Fix LTO parameter sharing

[Richard Guenther]

On Wed, Nov 11, 2009 at 2:30 PM, Diego Novillo <dnovillo@google.com> wrote:
> On Wed, Nov 11, 2009 at 15:20, Jan Hubicka <hubicka@ucw.cz> wrote:
>
>> I've bootstrapped/regtested patch on x86_64-linux and intend to check it in shortly.
>
> Nit: You actually need a review for these kinds of changes.

Indeed.  I wrote the patch, so I probably cannot use the excuse that
Honza posted it to circumvent my LTO reviewer status ;)  But it's sort-of
middle-end anyway ... (I "approved" it from the seat right next of Honza)

Richard.

>>
>> Honza
>>
>>        * lto-streamer-out.c (output_function): Output head of argument list
>>        earlier.
>>        * lto-streamer-in.c (input_function): Re-map arguments into merged
>>        declaration.
>
> OK.
>
>
> Diego.
>

Re: Fix LTO parameter sharing

[Diego Novillo]

On Wed, Nov 11, 2009 at 15:41, Richard Guenther
<richard.guenther@gmail.com> wrote:

> Indeed.  I wrote the patch, so I probably cannot use the excuse that
> Honza posted it to circumvent my LTO reviewer status ;)  But it's sort-of
> middle-end anyway ... (I "approved" it from the seat right next of Honza)

Ha ha.  That's fine.  I figured that something like that had happened,
but I'm bored, so... ;)


Diego.