Merge lp:~rsandifo/gcc-linaro/lp-714921-4.6 into lp:gcc-linaro/4.6

[Richard Sandiford]

Simple backport of 4.7 patch.

[Linaro Toolchain Builder (cbuild)]

cbuild has taken a snapshot of this branch at r106545 and queued it for build.

The snapshot is available at:
 http://ex.seabright.co.nz/snapshots/gcc-linaro-4.6+bzr106545~rsandifo~lp-714921-4.6.tar.xdelta3.xz

and will be built on the following builders:
 a9-builder i686 x86_64

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 http://ex.seabright.co.nz/helpers/scheduler

cbuild-snapshot: gcc-linaro-4.6+bzr106545~rsandifo~lp-714921-4.6
cbuild-ancestor: lp:gcc-linaro/4.6+bzr106544
cbuild-state: check

[Linaro Toolchain Builder (cbuild)]

cbuild successfully built this on i686-lucid-cbuild112-scorpius-i686r1.

The build results are available at:
 http://ex.seabright.co.nz/build/gcc-linaro-4.6+bzr106545~rsandifo~lp-714921-4.6/logs/i686-lucid-cbuild112-scorpius-i686r1

The test suite results were unchanged compared to the branch point lp:gcc-linaro/4.6+bzr106544.

The full testsuite results are at:
 http://ex.seabright.co.nz/build/gcc-linaro-4.6+bzr106545~rsandifo~lp-714921-4.6/logs/i686-lucid-cbuild112-scorpius-i686r1/gcc-testsuite.txt

cbuild-checked: i686-lucid-cbuild112-scorpius-i686r1

[Linaro Toolchain Builder (cbuild)]

cbuild successfully built this on x86_64-maverick-cbuild112-crucis-x86_64r1.

The build results are available at:
 http://ex.seabright.co.nz/build/gcc-linaro-4.6+bzr106545~rsandifo~lp-714921-4.6/logs/x86_64-maverick-cbuild112-crucis-x86_64r1

The test suite results were unchanged compared to the branch point lp:gcc-linaro/4.6+bzr106544.

The full testsuite results are at:
 http://ex.seabright.co.nz/build/gcc-linaro-4.6+bzr106545~rsandifo~lp-714921-4.6/logs/x86_64-maverick-cbuild112-crucis-x86_64r1/gcc-testsuite.txt

cbuild-checked: x86_64-maverick-cbuild112-crucis-x86_64r1

[Linaro Toolchain Builder (cbuild)]

cbuild successfully built this on armv7l-maverick-cbuild112-ursa2-cortexa9r1.

The build results are available at:
 http://ex.seabright.co.nz/build/gcc-linaro-4.6+bzr106545~rsandifo~lp-714921-4.6/logs/armv7l-maverick-cbuild112-ursa2-cortexa9r1

The test suite results changed compared to the branch point lp:gcc-linaro/4.6+bzr106544:
 -FAIL: largefile.c -O0 -I. (internal compiler error)
 -FAIL: largefile.c -O0 -I. (test for excess errors)
 +PASS: largefile.c -O0 -I. (test for excess errors)
 -PASS: ext/mt_allocator/tune-4.cc execution test
 +FAIL: ext/mt_allocator/tune-4.cc execution test
 +WARNING: program timed out.

The full testsuite results are at:
 http://ex.seabright.co.nz/build/gcc-linaro-4.6+bzr106545~rsandifo~lp-714921-4.6/logs/armv7l-maverick-cbuild112-ursa2-cortexa9r1/gcc-testsuite.txt

cbuild-checked: armv7l-maverick-cbuild112-ursa2-cortexa9r1

[Ramana Radhakrishnan (ramana)]

 -PASS: ext/mt_allocator/tune-4.cc execution test
 +FAIL: ext/mt_allocator/tune-4.cc execution test

I'm a bit concerned about the extra failure here with a time-out . Could you have a quick look at this ?

Ramana

[Richard Sandiford (rsandifo)]

> -PASS: ext/mt_allocator/tune-4.cc execution test
> +FAIL: ext/mt_allocator/tune-4.cc execution test
>
> I'm a bit concerned about the extra failure here with a time-out . Could you
> have a quick look at this ?

Sure, np. I checked that it does pass locally on my Beagleboard. I also
checked that there were no code changes in the testcase: stripping both
the "before" and "after" executables gives output that is byte-for-byte
identical. The only difference between the original (non-stripped)
executables is that the debug info in the "after" executable is smaller.

That's all as hoped, of course. The patch is just supposed to change
the debug information, and is supposed to remove redundant location lists.

Richard

[Ramana Radhakrishnan (ramana)]

Approved but watch out for potential conflicts in Changelog and add an entry to Changelog.linaro.

cheers
Ramana

review: Approve

=== modified file 'gcc/ChangeLog'
--- gcc/ChangeLog	2011-04-07 10:52:12 +0000
+++ gcc/ChangeLog	2011-04-21 11:59:30 +0000
@@ -1,3 +1,4 @@
+<<<<<<< TREE
 2011-04-01  Ulrich Weigand  <[e-mail]>
 
 	* config/spu/t-spu-elf (dp-bit.c): Use > instead of >>.
@@ -2106,6 +2107,33 @@
 	* config/darwin.c (SECTION_NO_ANCHOR): Define.
 	(darwin_init_sections): Remove assertion.
 
+=======
[phone]  Richard Sandiford  <[e-mail]>
+
+	Backport from mainline:
+
+	2011-03-29  Richard Sandiford  <[e-mail]>
+
+	PR debug/48190
+	* dwarf2out.c (dw_loc_list_node): Add resolved_addr and replaced.
+	(cached_dw_loc_list_def): New structure.
+	(cached_dw_loc_list): New typedef.
+	(cached_dw_loc_list_table): New variable.
+	(cached_dw_loc_list_table_hash): New function.
+	(cached_dw_loc_list_table_eq): Likewise.
+	(add_location_or_const_value_attribute): Take a bool cache_p.
+	Cache the list when the parameter is true.
+	(gen_formal_parameter_die): Update caller.
+	(gen_variable_die): Likewise.
+	(dwarf2out_finish): Likewise.
+	(dwarf2out_abstract_function): Nullify cached_dw_loc_list_table
+	while generating debug info for the decl.
+	(dwarf2out_function_decl): Clear cached_dw_loc_list_table.
+	(dwarf2out_init): Initialize cached_dw_loc_list_table.
+	(resolve_addr): Cache the result of resolving a chain of
+	location lists.
+
+>>>>>>> MERGE-SOURCE
 2011-02-03  Nick Clifton  <[e-mail]>
 
 	* config/rx/predicates.md (rx_zs_comparison_operator): Remove

=== modified file 'gcc/dwarf2out.c'
--- gcc/dwarf2out.c	2011-03-29 22:47:59 +0000
+++ gcc/dwarf2out.c	2011-04-21 11:59:30 +0000
@@ -4427,6 +4427,11 @@
   const char *section; /* Section this loclist is relative to */
   dw_loc_descr_ref expr;
   hashval_t hash;
+  /* True if all addresses in this and subsequent lists are known to be
+     resolved.  */
+  bool resolved_addr;
+  /* True if this list has been replaced by dw_loc_next.  */
+  bool replaced;
   bool emitted;
 } dw_loc_list_node;
 
@@ -6087,6 +6092,19 @@
 /* Table of decl location linked lists.  */
 static GTY ((param_is (var_loc_list))) htab_t decl_loc_table;
 
+/* A cached location list.  */
+struct GTY (()) cached_dw_loc_list_def {
+  /* The DECL_UID of the decl that this entry describes.  */
+  unsigned int decl_id;
+
+  /* The cached location list.  */
+  dw_loc_list_ref loc_list;
+};
+typedef struct cached_dw_loc_list_def cached_dw_loc_list;
+
+/* Table of cached location lists.  */
+static GTY ((param_is (cached_dw_loc_list))) htab_t cached_dw_loc_list_table;
+
 /* A pointer to the base of a list of references to DIE's that
    are uniquely identified by their tag, presence/absence of
    children DIE's, and list of attribute/value pairs.  */
@@ -6434,7 +6452,7 @@
 static void insert_double (double_int, unsigned char *);
 static void insert_float (const_rtx, unsigned char *);
 static rtx rtl_for_decl_location (tree);
-static bool add_location_or_const_value_attribute (dw_die_ref, tree,
+static bool add_location_or_const_value_attribute (dw_die_ref, tree, bool,
 						   enum dwarf_attribute);
 static bool tree_add_const_value_attribute (dw_die_ref, tree);
 static bool tree_add_const_value_attribute_for_decl (dw_die_ref, tree);
@@ -8168,6 +8186,24 @@
     htab_find_with_hash (decl_loc_table, decl, DECL_UID (decl));
 }
 
+/* Returns a hash value for X (which really is a cached_dw_loc_list_list).  */
+
+static hashval_t
+cached_dw_loc_list_table_hash (const void *x)
+{
+  return (hashval_t) ((const cached_dw_loc_list *) x)->decl_id;
+}
+
+/* Return nonzero if decl_id of cached_dw_loc_list X is the same as
+   UID of decl *Y.  */
+
+static int
+cached_dw_loc_list_table_eq (const void *x, const void *y)
+{
+  return (((const cached_dw_loc_list *) x)->decl_id
+	  == DECL_UID ((const_tree) y));
+}
+
 /* Equate a DIE to a particular declaration.  */
 
 static void
@@ -16965,15 +17001,22 @@
    these things can crop up in other ways also.)  Note that one type of
    constant value which can be passed into an inlined function is a constant
    pointer.  This can happen for example if an actual argument in an inlined
-   function call evaluates to a compile-time constant address.  */
+   function call evaluates to a compile-time constant address.
+
+   CACHE_P is true if it is worth caching the location list for DECL,
+   so that future calls can reuse it rather than regenerate it from scratch.
+   This is true for BLOCK_NONLOCALIZED_VARS in inlined subroutines,
+   since we will need to refer to them each time the function is inlined.  */
 
 static bool
-add_location_or_const_value_attribute (dw_die_ref die, tree decl,
+add_location_or_const_value_attribute (dw_die_ref die, tree decl, bool cache_p,
 				       enum dwarf_attribute attr)
 {
   rtx rtl;
   dw_loc_list_ref list;
   var_loc_list *loc_list;
+  cached_dw_loc_list *cache;
+  void **slot;
 
   if (TREE_CODE (decl) == ERROR_MARK)
     return false;
@@ -17010,7 +17053,33 @@
 	  && add_const_value_attribute (die, rtl))
 	 return true;
     }
-  list = loc_list_from_tree (decl, decl_by_reference_p (decl) ? 0 : 2);
+  /* If this decl is from BLOCK_NONLOCALIZED_VARS, we might need its
+     list several times.  See if we've already cached the contents.  */
+  list = NULL;
+  if (loc_list == NULL || cached_dw_loc_list_table == NULL)
+    cache_p = false;
+  if (cache_p)
+    {
+      cache = (cached_dw_loc_list *)
+	htab_find_with_hash (cached_dw_loc_list_table, decl, DECL_UID (decl));
+      if (cache)
+	list = cache->loc_list;
+    }
+  if (list == NULL)
+    {
+      list = loc_list_from_tree (decl, decl_by_reference_p (decl) ? 0 : 2);
+      /* It is usually worth caching this result if the decl is from
+	 BLOCK_NONLOCALIZED_VARS and if the list has at least two elements.  */
+      if (cache_p && list && list->dw_loc_next)
+	{
+	  slot = htab_find_slot_with_hash (cached_dw_loc_list_table, decl,
+					   DECL_UID (decl), INSERT);
+	  cache = ggc_alloc_cleared_cached_dw_loc_list ();
+	  cache->decl_id = DECL_UID (decl);
+	  cache->loc_list = list;
+	  *slot = cache;
+	}
+    }
   if (list)
     {
       add_AT_location_description (die, attr, list);
@@ -18702,7 +18771,7 @@
         equate_decl_number_to_die (node, parm_die);
       if (! DECL_ABSTRACT (node_or_origin))
 	add_location_or_const_value_attribute (parm_die, node_or_origin,
-					       DW_AT_location);
+					       node == NULL, DW_AT_location);
 
       break;
 
@@ -18887,6 +18956,7 @@
   tree context;
   int was_abstract;
   htab_t old_decl_loc_table;
+  htab_t old_cached_dw_loc_list_table;
 
   /* Make sure we have the actual abstract inline, not a clone.  */
   decl = DECL_ORIGIN (decl);
@@ -18901,6 +18971,8 @@
      get locations in abstract instantces.  */
   old_decl_loc_table = decl_loc_table;
   decl_loc_table = NULL;
+  old_cached_dw_loc_list_table = cached_dw_loc_list_table;
+  cached_dw_loc_list_table = NULL;
 
   /* Be sure we've emitted the in-class declaration DIE (if any) first, so
      we don't get confused by DECL_ABSTRACT.  */
@@ -18925,6 +18997,7 @@
 
   current_function_decl = save_fn;
   decl_loc_table = old_decl_loc_table;
+  cached_dw_loc_list_table = old_cached_dw_loc_list_table;
   pop_cfun ();
 }
 
@@ -19709,9 +19782,8 @@
           && !TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl_or_origin)))
 	defer_location (decl_or_origin, var_die);
       else
-        add_location_or_const_value_attribute (var_die,
-					       decl_or_origin,
-					       DW_AT_location);
+        add_location_or_const_value_attribute (var_die, decl_or_origin,
+					       decl == NULL, DW_AT_location);
       add_pubname (decl_or_origin, var_die);
     }
   else
@@ -21498,6 +21570,7 @@
   dwarf2out_decl (decl);
 
   htab_empty (decl_loc_table);
+  htab_empty (cached_dw_loc_list_table);
 }
 
 /* Output a marker (i.e. a label) for the beginning of the generated code for
@@ -22230,6 +22303,11 @@
   decl_loc_table = htab_create_ggc (10, decl_loc_table_hash,
 				    decl_loc_table_eq, NULL);
 
+  /* Allocate the cached_dw_loc_list_table.  */
+  cached_dw_loc_list_table
+    = htab_create_ggc (10, cached_dw_loc_list_table_hash,
+		       cached_dw_loc_list_table_eq, NULL);
+
   /* Allocate the initial hunk of the decl_scope_table.  */
   decl_scope_table = VEC_alloc (tree, gc, 256);
 
@@ -22870,30 +22948,53 @@
 {
   dw_die_ref c;
   dw_attr_ref a;
-  dw_loc_list_ref *curr;
+  dw_loc_list_ref *curr, *start, loc;
   unsigned ix;
 
   FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
     switch (AT_class (a))
       {
       case dw_val_class_loc_list:
-	curr = AT_loc_list_ptr (a);
-	while (*curr)
+	start = curr = AT_loc_list_ptr (a);
+	loc = *curr;
+	gcc_assert (loc);
+	/* The same list can be referenced more than once.  See if we have
+	   already recorded the result from a previous pass.  */
+	if (loc->replaced)
+	  *curr = loc->dw_loc_next;
+	else if (!loc->resolved_addr)
 	  {
-	    if (!resolve_addr_in_expr ((*curr)->expr))
+	    /* As things stand, we do not expect or allow one die to
+	       reference a suffix of another die's location list chain.
+	       References must be identical or completely separate.
+	       There is therefore no need to cache the result of this
+	       pass on any list other than the first; doing so
+	       would lead to unnecessary writes.  */
+	    while (*curr)
 	      {
-		dw_loc_list_ref next = (*curr)->dw_loc_next;
-		if (next && (*curr)->ll_symbol)
+		gcc_assert (!(*curr)->replaced && !(*curr)->resolved_addr);
+		if (!resolve_addr_in_expr ((*curr)->expr))
 		  {
-		    gcc_assert (!next->ll_symbol);
-		    next->ll_symbol = (*curr)->ll_symbol;
+		    dw_loc_list_ref next = (*curr)->dw_loc_next;
+		    if (next && (*curr)->ll_symbol)
+		      {
+			gcc_assert (!next->ll_symbol);
+			next->ll_symbol = (*curr)->ll_symbol;
+		      }
+		    *curr = next;
 		  }
-		*curr = next;
+		else
+		  curr = &(*curr)->dw_loc_next;
 	      }
+	    if (loc == *start)
+	      loc->resolved_addr = 1;
 	    else
-	      curr = &(*curr)->dw_loc_next;
+	      {
+		loc->replaced = 1;
+		loc->dw_loc_next = *start;
+	      }
 	  }
-	if (!AT_loc_list (a))
+	if (!*start)
 	  {
 	    remove_AT (die, a->dw_attr);
 	    ix--;
@@ -23322,6 +23423,7 @@
       add_location_or_const_value_attribute (
         VEC_index (deferred_locations, deferred_locations_list, i)->die,
         VEC_index (deferred_locations, deferred_locations_list, i)->variable,
+	false,
 	DW_AT_location);
     }