Common API for accessing global and on-demand ranges.

This patch provides a generic API for accessing global ranges.  It is
meant to replace get_range_info() and get_ptr_nonnull() with one
common interface.  It uses the same API as the ranger (class
range_query), so there will now be one API for accessing local and
global ranges alike.

Follow-up patches will convert all users of get_range_info and
get_ptr_nonnull to this API.

For get_range_info, instead of:

  if (!POINTER_TYPE_P (TREE_TYPE (name)) && SSA_NAME_RANGE_INFO (name))
    get_range_info (name, vr);

You can now do:

  get_range_query (cfun)->range_of_expr (vr, name, [stmt]);

...as well as any other of the range_query methods (range_on_edge,
range_of_stmt, value_of_expr, value_on_edge, value_on_stmt, etc).

As per the API, range_of_expr will work on constants, SSA names, and
anything we support in irange::supports_type_p().

For pointers, the interface is the same, so instead of:

  else if (POINTER_TYPE_P (TREE_TYPE (name)) && SSA_NAME_PTR_INFO (name))
    {
      if (get_ptr_nonnull (name))
        stuff();
    }

One can do:

  get_range_query (cfun)->range_of_expr (vr, name, [stmt]);
  if (vr.nonzero_p ())
    stuff ();

Along with this interface, we are providing a mechanism by which a
pass can use an on-demand ranger transparently, without having to
change its code.  Of course, this assumes all get_range_info() and
get_ptr_nonnull() users have been converted to the new API, which
follow-up patches will do.

If a pass would prefer to use an on-demand ranger with finer grained
and context aware ranges, all it would have to do is call
enable_ranger() at the beginning of the pass, and disable_ranger() at
the end of the pass.

Note, that to use context aware ranges, any user of range_of_expr()
would need to pass additional context.  For example, the optional
gimple statement (or perhaps use range_on_edge or range_of_stmt).

The observant reader will note that get_range_query is tied to a
struct function, which may not be available in certain contexts, such
as at RTL time, gimple-fold, or some other places where we may or may
not have cfun set.

For cases where we are sure there is no function, you can use
get_global_range_query() instead of get_range_query(fun).  The API is
the same.

For cases where a function may be called with or without a function,
you could use the following idiom:

  range_query *query = cfun ? get_range_query (cfun)
    : get_global_range_query ();

  query->range_of_expr (range, expr, [stmt]);

The default range query obtained by get_range_query() is the global
range query, unless the user has enabled an on-demand ranger with
enable_ranger(), in which case it will use the currently active ranger.
That is, until disable_ranger() is called, at which point, we revert
back to global ranges.

We think this provides a generic way of accessing ranges, both
globally and locally, without having to keep track of types,
SSA_NAME_RANGE_INFO, and SSA_NAME_PTR_INFO.  We also hope this can be
used to transition passes from global to on-demand ranges when
appropriate.

gcc/ChangeLog:

	* function.c (allocate_struct_function): Set cfun->x_range_query.
	* function.h (struct function): Declare x_range_query.
	(get_range_query): New.
	(get_global_range_query): New.
	* gimple-range-cache.cc (ssa_global_cache::ssa_global_cache):
	Remove call to safe_grow_cleared.
	* gimple-range.cc (get_range_global): New.
	(gimple_range_global): Move from gimple-range.h.
	(get_global_range_query): New.
	(global_range_query::range_of_expr): New.
	(enable_ranger): New.
	(disable_ranger): New.
	* gimple-range.h (gimple_range_global): Move to gimple-range.cc.
	(class global_range_query): New.
	(enable_ranger): New.
	(disable_ranger): New.
	* gimple-ssa-evrp.c (evrp_folder::~evrp_folder): Rename
	dump_all_value_ranges to dump.
	* tree-vrp.c (vrp_prop::finalize): Same.
	* value-query.cc (range_query::dump): New.
	* value-query.h (range_query::dump): New.
	* vr-values.c (vr_values::dump_all_value_ranges): Rename to...
	(vr_values::dump): ...this.
	* vr-values.h (class vr_values): Rename dump_all_value_ranges to
	dump and make virtual.

1 files changed, 15 insertions, 45 deletions

diff --git a/gcc/gimple-range.h b/gcc/gimple-range.h
index 707dcfe..23734c6 100644
--- a/gcc/gimple-range.h
+++ b/gcc/gimple-range.h
@@ -65,7 +65,7 @@ public:
   virtual void range_on_entry (irange &r, basic_block bb, tree name);
   virtual void range_on_exit (irange &r, basic_block bb, tree name);
   void export_global_ranges ();
-  void dump (FILE *f);
+  virtual void dump (FILE *f) OVERRIDE;
   void dump_bb (FILE *f, basic_block bb);
 protected:
   bool fold_range_internal (irange &r, gimple *s, tree name);
@@ -227,50 +227,6 @@ range_compatible_p (tree type1, tree type2)
 	  && TYPE_SIGN (type1) == TYPE_SIGN (type2));
 }
 
-// Return the legacy GCC global range for NAME if it has one, otherwise
-// return VARYING.
-
-static inline value_range
-gimple_range_global (tree name)
-{
-  gcc_checking_assert (gimple_range_ssa_p (name));
-  tree type = TREE_TYPE (name);
-
-  if (SSA_NAME_IS_DEFAULT_DEF (name))
-    {
-      tree sym = SSA_NAME_VAR (name);
-      // Adapted from vr_values::get_lattice_entry().
-      // Use a range from an SSA_NAME's available range.
-      if (TREE_CODE (sym) == PARM_DECL)
-	{
-	  // Try to use the "nonnull" attribute to create ~[0, 0]
-	  // anti-ranges for pointers.  Note that this is only valid with
-	  // default definitions of PARM_DECLs.
-	  if (POINTER_TYPE_P (type)
-	      && (nonnull_arg_p (sym) || get_ptr_nonnull (name)))
-	    {
-	      value_range r;
-	      r.set_nonzero (type);
-	      return r;
-	    }
-	  else if (INTEGRAL_TYPE_P (type))
-	    {
-	      value_range r;
-	      get_range_info (name, r);
-	      if (r.undefined_p ())
-		r.set_varying (type);
-	      return r;
-	    }
-	}
-      // If this is a local automatic with no definition, use undefined.
-      else if (TREE_CODE (sym) != RESULT_DECL)
-	return value_range ();
-   }
-  // Otherwise return range for the type.
-  return value_range (type);
-}
-
-
 // This class overloads the ranger routines to provide tracing facilties
 // Entry and exit values to each of the APIs is placed in the dumpfile.
 
@@ -296,4 +252,18 @@ private:
 // Flag to enable debugging the various internal Caches.
 #define DEBUG_RANGE_CACHE (dump_file && (param_evrp_mode & EVRP_MODE_DEBUG))
 
+// Global ranges for SSA names using SSA_NAME_RANGE_INFO.
+
+class global_range_query : public range_query
+{
+public:
+  bool range_of_expr (irange &r, tree expr, gimple * = NULL) OVERRIDE;
+};
+
+extern global_range_query global_ranges;
+extern value_range gimple_range_global (tree name);
+
+extern gimple_ranger *enable_ranger (struct function *);
+extern void disable_ranger (struct function *);
+
 #endif // GCC_GIMPLE_RANGE_STMT_H