ipa-prop.h

/* Interprocedural analyses.
   Copyright (C) 2005, 2007, 2008 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#ifndef IPA_PROP_H
#define IPA_PROP_H

#include "tree.h"
#include "vec.h"
#include "cgraph.h"

/* The following definitions and interfaces are used by
   interprocedural analyses.  */

/* A jump function for a callsite represents the values passed as actual
   arguments of the callsite. There are three main types of values :
   Formal - the caller's formal parameter is passed as an actual argument.
   Constant - a constant is passed as an actual argument.
   Unknown - neither of the above.
   Integer and real constants are represented as IPA_CONST.
   Finally, IPA_CONST_MEMBER_PTR stands for C++ member pointers constants.  */
enum jump_func_type
{
  IPA_UNKNOWN = 0,     /* newly allocated and zeroed jump functions default */
  IPA_CONST,
  IPA_CONST_MEMBER_PTR,
  IPA_PASS_THROUGH
};

/* All formal parameters in the program have a lattice associated with it
   computed by the interprocedural stage of IPCP.
   There are three main values of the lattice:
   IPA_TOP - unknown,
   IPA_BOTTOM - non constant,
   IPA_CONST_VALUE - simple scalar constant,
   Cval of formal f will have a constant value if all callsites to this
   function have the same constant value passed to f.
   Integer and real constants are represented as IPA_CONST.  */
enum ipa_lattice_type
{
  IPA_BOTTOM,
  IPA_CONST_VALUE,
  IPA_TOP
};

/* Structure holding a C++ member pointer constant.  Holds a pointer to the
   method and delta offset.  */
struct ipa_member_ptr_cst
{
  tree pfn;
  tree delta;
};

/* Represents a value of a jump function.  formal_id is used only in jump
   function context and represents pass-through parameter (the formal parameter
   of the caller is passed as argument).  constant represents the actual
   constant in constant jump functions and member_cst holds constant c++ member
   functions.  */
union jump_func_value
{
  unsigned int formal_id;
  tree constant;
  struct ipa_member_ptr_cst member_cst;
};

/* A jump function for a callsite represents the values passed as actual
   arguments of the callsite. See enum jump_func_type for the various
   types of jump functions supported.  */
struct ipa_jump_func
{
  enum jump_func_type type;
  union jump_func_value value;
};

/* All formal parameters in the program have a cval computed by
   the interprocedural stage of IPCP. See enum ipa_lattice_type for
   the various types of lattices supported */
struct ipcp_lattice
{
  enum ipa_lattice_type type;
  tree constant;
};

/* Represent which DECL tree (or reference to such tree)
   will be replaced by another tree while versioning.  */
struct ipa_replace_map
{
  /* The tree that will be replaced.  */
  tree old_tree;
  /* The new (replacing) tree.  */
  tree new_tree;
  /* True when a substitution should be done, false otherwise.  */
  bool replace_p;
  /* True when we replace a reference to old_tree.  */
  bool ref_p;
};

/* Each instance of the following  structure describes a statement that calls a
   function parameter.  Those referring  to statements within the same function
   are linked in a list.  */
struct ipa_param_call_note
{
  /* Linked list's next */
  struct ipa_param_call_note *next;
  /* Statement that contains the call to the parameter above.  */
  gimple stmt;
  /* Index of the parameter that is called.  */
  unsigned int formal_id;
  /* Expected number of executions: calculated in profile.c.  */
  gcov_type count;
  /* Expected frequency of executions within the function. see cgraph_edge in
     cgraph.h for more on this. */
  int frequency;
  /* Depth of loop nest, 1 means no loop nest.  */
  int loop_nest;
  /* Set when we have already found the target to be a compile time constant
     and turned this into an edge or when the note was found unusable for some
     reason.  */
  bool processed;
};

/* Structure describing a single formal parameter.  */
struct ipa_param_descriptor
{
  /* IPA-CP lattice.  */
  struct ipcp_lattice ipcp_lattice;
  /* PARAM_DECL of this parameter.  */
  tree decl;
  /* Whether the value parameter has been modified within the function.  */
  unsigned modified : 1;
  /* Whether the parameter has been used as a call destination. */
  unsigned called : 1;
};

/* ipa_node_params stores information related to formal parameters of functions
   and some other information for interprocedural passes that operate on
   parameters (such as ipa-cp).  */
struct ipa_node_params
{
  /* Number of formal parameters of this function.  When set to 0,
     this function's parameters would not be analyzed by the different
     stages of IPA CP.  */
  int param_count;
  /* Pointer to an array of structures describing individual formal
     parameters.  */
  struct ipa_param_descriptor *params;
  /* List of structures enumerating calls to a formal parameter.  */
  struct ipa_param_call_note *param_calls;
  /* Only for versioned nodes this field would not be NULL,
     it points to the node that IPA cp cloned from.  */
  struct cgraph_node *ipcp_orig_node;
  /* Meaningful only for original functions.  Expresses the
     ratio between the direct calls and sum of all invocations of
     this function (given by profiling info).  It is used to calculate
     the profiling information of the original function and the versioned
     one.  */
  gcov_type count_scale;

  /* Whether this function is called with variable number of actual
     arguments.  */
  unsigned called_with_var_arguments : 1;
  /* Whether the modification analysis has already been performed. */
  unsigned modification_analysis_done : 1;
  /* Whether the param uses analysis has already been performed.  */
  unsigned uses_analysis_done : 1;
};

/* ipa_node_params access functions.  Please use these to access fields that
   are or will be shared among various passes.  */

/* Set the number of formal parameters. */

static inline void
ipa_set_param_count (struct ipa_node_params *info, int count)
{
  info->param_count = count;
}

/* Return the number of formal parameters. */

static inline int
ipa_get_param_count (struct ipa_node_params *info)
{
  return info->param_count;
}

/* Return the declaration of Ith formal parameter of the function corresponding
   to INFO.  Note there is no setter function as this array is built just once
   using ipa_initialize_node_params. */

static inline tree
ipa_get_param (struct ipa_node_params *info, int i)
{
  return info->params[i].decl;
}

/* Return the modification flag corresponding to the Ith formal parameter of
   the function associated with INFO.  Note that there is no setter method as
   the goal is to set all flags when building the array in
   ipa_detect_param_modifications.  */

static inline bool
ipa_is_param_modified (struct ipa_node_params *info, int i)
{
  return info->params[i].modified;
}

/* Return the called flag corresponding to the Ith formal parameter of the
   function associated with INFO.  Note that there is no setter method as the
   goal is to set all flags when building the array in
   ipa_detect_called_params.  */

static inline bool
ipa_is_param_called (struct ipa_node_params *info, int i)
{
  return info->params[i].called;
}

/* Flag this node as having callers with variable number of arguments.  */

static inline void
ipa_set_called_with_variable_arg (struct ipa_node_params *info)
{
  info->called_with_var_arguments = 1;
}

/* Have we detected this node was called with variable number of arguments? */

static inline bool
ipa_is_called_with_var_arguments (struct ipa_node_params *info)
{
  return info->called_with_var_arguments;
}



/* ipa_edge_args stores information related to a callsite and particularly
   its arguments. It is pointed to by a field in the
   callsite's corresponding cgraph_edge.  */
struct ipa_edge_args
{
  /* Number of actual arguments in this callsite.  When set to 0,
     this callsite's parameters would not be analyzed by the different
     stages of IPA CP.  */
  int argument_count;
  /* Array of the callsite's jump function of each parameter.  */
  struct ipa_jump_func *jump_functions;
};

/* ipa_edge_args access functions.  Please use these to access fields that
   are or will be shared among various passes.  */

/* Set the number of actual arguments. */

static inline void
ipa_set_cs_argument_count (struct ipa_edge_args *args, int count)
{
  args->argument_count = count;
}

/* Return the number of actual arguments. */

static inline int
ipa_get_cs_argument_count (struct ipa_edge_args *args)
{
  return args->argument_count;
}

/* Returns a pointer to the jump function for the ith argument.  Please note
   there is no setter function as jump functions are all set up in
   ipa_compute_jump_functions. */

static inline struct ipa_jump_func *
ipa_get_ith_jump_func (struct ipa_edge_args *args, int i)
{
  return &args->jump_functions[i];
}

/* Vectors need to have typedefs of structures.  */
typedef struct ipa_node_params ipa_node_params_t;
typedef struct ipa_edge_args ipa_edge_args_t;

/* Types of vectors holding the infos.  */
DEF_VEC_O (ipa_node_params_t);
DEF_VEC_ALLOC_O (ipa_node_params_t, heap);
DEF_VEC_O (ipa_edge_args_t);
DEF_VEC_ALLOC_O (ipa_edge_args_t, heap);

/* Vector where the parameter infos are actually stored. */
extern VEC (ipa_node_params_t, heap) *ipa_node_params_vector;
/* Vector where the parameter infos are actually stored. */
extern VEC (ipa_edge_args_t, heap) *ipa_edge_args_vector;

/* Return the associated parameter/argument info corresponding to the given
   node/edge.  */
#define IPA_NODE_REF(NODE) (VEC_index (ipa_node_params_t, \
				       ipa_node_params_vector, (NODE)->uid))
#define IPA_EDGE_REF(EDGE) (VEC_index (ipa_edge_args_t, \
				       ipa_edge_args_vector, (EDGE)->uid))
/* This macro checks validity of index returned by
   ipa_get_param_decl_index function.  */
#define IS_VALID_JUMP_FUNC_INDEX(I) ((I) != -1)

/* Creating and freeing ipa_node_params and ipa_edge_args.  */
void ipa_create_all_node_params (void);
void ipa_create_all_edge_args (void);
void ipa_free_edge_args_substructures (struct ipa_edge_args *);
void ipa_free_node_params_substructures (struct ipa_node_params *);
void ipa_free_all_node_params (void);
void ipa_free_all_edge_args (void);
void free_all_ipa_structures_after_ipa_cp (void);
void free_all_ipa_structures_after_iinln (void);
void ipa_register_cgraph_hooks (void);

/* This function ensures the array of node param infos is big enough to
   accommodate a structure for all nodes and reallocates it if not.  */

static inline void
ipa_check_create_node_params (void)
{
  if (!ipa_node_params_vector)
    ipa_node_params_vector = VEC_alloc (ipa_node_params_t, heap,
					cgraph_max_uid);

  if (VEC_length (ipa_node_params_t, ipa_node_params_vector)
      <= (unsigned) cgraph_max_uid)
    VEC_safe_grow_cleared (ipa_node_params_t, heap,
			   ipa_node_params_vector, cgraph_max_uid + 1);
}

/* This function ensures the array of edge arguments infos is big enough to
   accommodate a structure for all edges and reallocates it if not.  */

static inline void
ipa_check_create_edge_args (void)
{
  if (!ipa_edge_args_vector)
    ipa_edge_args_vector = VEC_alloc (ipa_edge_args_t, heap,
				      cgraph_edge_max_uid);

  if (VEC_length (ipa_edge_args_t, ipa_edge_args_vector)
      <=  (unsigned) cgraph_edge_max_uid)
    VEC_safe_grow_cleared (ipa_edge_args_t, heap, ipa_edge_args_vector,
			   cgraph_edge_max_uid + 1);
}

/* Returns true if the array of edge infos is large enough to accommodate an
   info for EDGE.  The main purpose of this function is that debug dumping
   function can check info availability without causing reallocations.  */

static inline bool
ipa_edge_args_info_available_for_edge_p (struct cgraph_edge *edge)
{
  return ((unsigned) edge->uid < VEC_length (ipa_edge_args_t,
					     ipa_edge_args_vector));
}

/* A function list element.  It is used to create a temporary worklist used in
   the propagation stage of IPCP. (can be used for more IPA optimizations)  */
struct ipa_func_list
{
  struct cgraph_node *node;
  struct ipa_func_list *next;
};

/* ipa_func_list interface.  */
struct ipa_func_list *ipa_init_func_list (void);
void ipa_push_func_to_list (struct ipa_func_list **, struct cgraph_node *);
struct cgraph_node *ipa_pop_func_from_list (struct ipa_func_list **);

/* Callsite related calculations.  */
void ipa_compute_jump_functions (struct cgraph_edge *);
void ipa_count_arguments (struct cgraph_edge *);

/* Function formal parameters related computations.  */
void ipa_initialize_node_params (struct cgraph_node *node);
void ipa_detect_param_modifications (struct cgraph_node *);
void ipa_analyze_params_uses (struct cgraph_node *);
bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
					VEC (cgraph_edge_p, heap) **new_edges);

/* Debugging interface.  */
void ipa_print_node_params (FILE *, struct cgraph_node *node);
void ipa_print_all_params (FILE *);
void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
void ipa_print_all_jump_functions (FILE * f);

#endif /* IPA_PROP_H */