New code to analyze file level static variables and to determine if...

New code to analyze file level static variables and to determine if
they escape and also code to use this information to prune clobber
lists.

From-SVN: r87455

1 files changed, 93 insertions, 0 deletions

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index a6e9cd7..0af4447 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -22,6 +22,8 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #ifndef GCC_CGRAPH_H
 #define GCC_CGRAPH_H
 #include "hashtab.h"
+#include "bitmap.h"
+#include "tree.h"
 
 /* Information about the function collected locally.
    Available after function is analyzed.  */
@@ -30,19 +32,37 @@ struct cgraph_local_info GTY(())
 {
   /* Size of the function before inlining.  */
   int self_insns;
+
   /* Set when function function is visible in current compilation unit only
      and it's address is never taken.  */
   bool local;
+
+  /* Set when function is defined in another compilation unit.  */
+  bool external;
+
+  /* Set when this function calls a function external of the
+     compilation unit.  In general, such calls are modeled as reading
+     and writing all variables (both bits on) but sometime there are
+     attributes on the called function so we can do better.  */
+  bool calls_read_all;
+  bool calls_write_all;
+
   /* Set once it has been finalized so we consider it to be output.  */
   bool finalized;
 
   /* False when there something makes inlining impossible (such as va_arg).  */
   bool inlinable;
+
   /* True when function should be inlined independently on it's size.  */
   bool disregard_inline_limits;
+
   /* True when the function has been originally extern inline, but it is
      redefined now.  */
   bool redefined_extern_inline;
+
+  /* True if statics_read_for_function and
+     statics_written_for_function contain valid data.  */
+  bool for_functions_valid;
 };
 
 /* Information about the function that needs to be computed globally
@@ -70,6 +90,69 @@ struct cgraph_rtl_info GTY(())
    bool pure_function;
 };
 
+/* FIXME -- PROFILE-RESTRUCTURE: When the next round of the profiling
+   code gets merged in, it will contain a restructing where ssa form
+   is built for every function within the compilation unit before the
+   rest of the compilation continues.  When this reorgination is done,
+   it will no longer be necessary to have the _decl_uid versions of
+   local_static_vars_info and global_static_vars_info structures.
+   Having both structures is now requirred because the _ann_uid values
+   for static variables are reset as each function is compiled.
+   Currently, the analysis is done using the _decl_uid versions and
+   converted to the _var_ann versions on demand.
+
+   Also, the var_anns_valid fields within these structures can also go
+   away.
+*/
+
+/* The static variables defined within the compilation unit that are
+   loaded or stored directly by function that owns this structure.  */ 
+
+struct local_static_vars_info_d GTY(())
+{
+  bitmap statics_read_by_decl_uid;
+  bitmap statics_written_by_decl_uid;
+};
+
+struct global_static_vars_info_d GTY(())
+{
+  bitmap statics_read_by_decl_uid;
+  bitmap statics_written_by_decl_uid;
+  bitmap statics_read_by_ann_uid;
+  bitmap statics_written_by_ann_uid;
+  bitmap statics_not_read_by_decl_uid;
+  bitmap statics_not_written_by_decl_uid;
+  bitmap statics_not_read_by_ann_uid;
+  bitmap statics_not_written_by_ann_uid;
+
+  /* var_anns_valid is reset at the start of compilation for each
+     function because the indexing that the "_var_anns" is based
+     on is invalidated between function compilations.  This allows for
+     lazy creation of the "_var_ann" variables.  */
+  bool var_anns_valid;
+};
+
+/* Statics that are read and written by some set of functions. The
+   local ones are based on the loads and stores local to the function.
+   The global ones are based on the local info as well as the
+   transitive closure of the functions that are called.  The
+   structures are separated to allow the global structures to be
+   shared between several functions since every function within a
+   strongly connected component will have the same information.  This
+   sharing saves both time and space in the computation of the vectors
+   as well as their translation from decl_uid form to ann_uid
+   form.  */ 
+
+typedef struct local_static_vars_info_d *local_static_vars_info_t;
+typedef struct global_static_vars_info_d *global_static_vars_info_t;
+
+struct static_vars_info_d GTY(()) 
+{
+  local_static_vars_info_t local;
+  global_static_vars_info_t global;
+};
+
+typedef struct static_vars_info_d *static_vars_info_t;
 
 /* The cgraph data structure.
    Each function decl has assigned cgraph_node listing callees and callers.  */
@@ -91,11 +174,18 @@ struct cgraph_node GTY((chain_next ("%h.next"), chain_prev ("%h.previous")))
   struct cgraph_node *next_needed;
   /* Pointer to the next clone.  */
   struct cgraph_node *next_clone;
+  /* Pointer to next node in a recursive call graph cycle; */
+  struct cgraph_node *next_cycle;
   PTR GTY ((skip)) aux;
 
   struct cgraph_local_info local;
   struct cgraph_global_info global;
   struct cgraph_rtl_info rtl;
+  
+  /* Pointer to the structure that contains the sets of global
+     variables modified by function calls.  */
+  static_vars_info_t static_vars_info;
+
   /* Unique id of the node.  */
   int uid;
   /* Set when function must be output - it is externally visible
@@ -192,6 +282,9 @@ void verify_cgraph_node (struct cgraph_node *);
 void cgraph_mark_inline_edge (struct cgraph_edge *e);
 void cgraph_clone_inlined_nodes (struct cgraph_edge *e, bool duplicate);
 void cgraph_build_static_cdtor (char which, tree body, int priority);
+void cgraph_reset_static_var_maps (void);
+bitmap get_global_statics_not_read (tree fn);
+bitmap get_global_statics_not_written(tree fn);
 void init_cgraph (void);
 
 #endif  /* GCC_CGRAPH_H  */