Re: [PATCH] Combine location with block using block_locations

[Martin Jambor <mjambor at suse dot cz>]

Hi,

On Wed, Sep 12, 2012 at 04:17:45PM +0200, Michael Matz wrote:
> Hi,
> 
> On Wed, 12 Sep 2012, Michael Matz wrote:
> 
> > > Hm, but we shouldn't end up streaming any BLOCKs at this point (nor 
> > > local TYPE_DECLs).  Those are supposed to be in the local function 
> > > sections only where no fixup for prevailing decls happens.
> > 
> > That's true, something is fishy with the patch, will try to investigate.
> 
> ipa-prop creates the problem.  Its tree mapping can contain expressions, 
> expressions can have locations, locations now have blocks.  The tree maps 
> are stored as part of jump functions, and hence as part of node summaries.  
> Node summaries are global, hence blocks, and therefore block vars can be 
> placed in the global blob.
> 
> That's not supposed to happen.  The patch below fixes this instance of the 
> problem and makes the testcase work with Dehaos patch with the 
> LTO_NO_PREVAIL call added back in.
> 

The following patch implements the unsharing and location pruning at
all required places in a way that passes bootstrap and testing on an
x86_64-linux.  Honza pre-approved it on IRC so unless there are any
objections within a few hours I'm going to commit it.

(The patch does not introduce any of the asserts Michael's patch had
because, as far as I my grep told me, IS_UNKNOWN_LOCATION is not in
trunk yet and I suppose the pre-approval does not cover introducing
things like that.)

Thanks,

Martin


2012-09-18  Martin Jambor  <mjambor@suse.cz>

	* ipa-prop.c (prune_expression_for_jf): New function.
	(ipa_set_jf_constant): Use it.
	(ipa_set_jf_arith_pass_through): Likewise.
	(determine_known_aggregate_parts): Likewise.

Index: src/gcc/ipa-prop.c
===================================================================
--- src.orig/gcc/ipa-prop.c
+++ src/gcc/ipa-prop.c
@@ -287,6 +287,19 @@ ipa_print_all_jump_functions (FILE *f)
     }
 }
 
+/* Return the expression tree EXPR unshared and with location stripped off.  */
+
+static tree
+prune_expression_for_jf (tree exp)
+{
+  if (EXPR_P (exp))
+    {
+      exp = unshare_expr (exp);
+      SET_EXPR_LOCATION (exp, UNKNOWN_LOCATION);
+    }
+  return exp;
+}
+
 /* Set JFUNC to be a known type jump function.  */
 
 static void
@@ -305,7 +318,7 @@ static void
 ipa_set_jf_constant (struct ipa_jump_func *jfunc, tree constant)
 {
   jfunc->type = IPA_JF_CONST;
-  jfunc->value.constant = constant;
+  jfunc->value.constant = prune_expression_for_jf (constant);
 }
 
 /* Set JFUNC to be a simple pass-through jump function.  */
@@ -327,7 +340,7 @@ ipa_set_jf_arith_pass_through (struct ip
 			       tree operand, enum tree_code operation)
 {
   jfunc->type = IPA_JF_PASS_THROUGH;
-  jfunc->value.pass_through.operand = operand;
+  jfunc->value.pass_through.operand = prune_expression_for_jf (operand);
   jfunc->value.pass_through.formal_id = formal_id;
   jfunc->value.pass_through.operation = operation;
   jfunc->value.pass_through.agg_preserved = false;
@@ -1344,7 +1357,7 @@ determine_known_aggregate_parts (gimple
 	    {
 	      struct ipa_agg_jf_item item;
 	      item.offset = list->offset - arg_offset;
-	      item.value = list->constant;
+	      item.value = prune_expression_for_jf (list->constant);
 	      VEC_quick_push (ipa_agg_jf_item_t, jfunc->agg.items, item);
 	    }
 	  list = list->next;