1  /* IPA reference lists.
       2     Copyright (C) 2010-2023 Free Software Foundation, Inc.
       3     Contributed by Jan Hubicka
       4  
       5  This file is part of GCC.
       6  
       7  GCC is free software; you can redistribute it and/or modify it under
       8  the terms of the GNU General Public License as published by the Free
       9  Software Foundation; either version 3, or (at your option) any later
      10  version.
      11  
      12  GCC is distributed in the hope that it will be useful, but WITHOUT ANY
      13  WARRANTY; without even the implied warranty of MERCHANTABILITY or
      14  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      15  for more details.
      16  
      17  You should have received a copy of the GNU General Public License
      18  along with GCC; see the file COPYING3.  If not see
      19  <http://www.gnu.org/licenses/>.  */
      20  
      21  #ifndef GCC_IPA_REF_H
      22  #define GCC_IPA_REF_H
      23  
      24  struct cgraph_node;
      25  struct varpool_node;
      26  struct symtab_node;
      27  
      28  
      29  /* How the reference is done.  */
      30  enum ipa_ref_use
      31  {
      32    IPA_REF_LOAD,
      33    IPA_REF_STORE,
      34    IPA_REF_ADDR,
      35    IPA_REF_ALIAS
      36  };
      37  
      38  /* Record of reference in callgraph or varpool.  */
      39  struct ipa_ref
      40  {
      41  public:
      42    /* Remove reference.  */
      43    void remove_reference ();
      44  
      45    /* Return true when execution of reference can lead to return from
      46       function.  */
      47    bool cannot_lead_to_return ();
      48  
      49    /* Return true if reference may be used in address compare.  */
      50    bool address_matters_p ();
      51  
      52    /* Return reference list this reference is in.  */
      53    struct ipa_ref_list * referring_ref_list (void);
      54  
      55    /* Return reference list this reference is in.  */
      56    struct ipa_ref_list * referred_ref_list (void);
      57  
      58    symtab_node *referring;
      59    symtab_node *referred;
      60    gimple *stmt;
      61    unsigned int lto_stmt_uid;
      62    unsigned int referred_index;
      63    /* speculative id is used to link direct calls with their corresponding
      64       IPA_REF_ADDR references when representing speculative calls.  */
      65    unsigned int speculative_id : 16;
      66    ENUM_BITFIELD (ipa_ref_use) use:3;
      67    unsigned int speculative:1;
      68  };
      69  
      70  typedef struct ipa_ref ipa_ref_t;
      71  
      72  
      73  /* List of references.  This is stored in both callgraph and varpool nodes.  */
      74  struct ipa_ref_list
      75  {
      76  public:
      77    /* Return first reference in list or NULL if empty.  */
      78    struct ipa_ref *first_reference (void)
      79    {
      80      if (!references.length ())
      81        return NULL;
      82      return &references[0];
      83    }
      84  
      85    /* Return first referring ref in list or NULL if empty.  */
      86    struct ipa_ref *first_referring (void)
      87    {
      88      if (!referring.length ())
      89        return NULL;
      90      return referring[0];
      91    }
      92  
      93    /* Return first referring alias.  */
      94    struct ipa_ref *first_alias (void)
      95    {
      96      struct ipa_ref *r = first_referring ();
      97  
      98      return r && r->use == IPA_REF_ALIAS ? r : NULL;
      99    }
     100  
     101    /* Return last referring alias.  */
     102    struct ipa_ref *last_alias (void)
     103    {
     104      unsigned int i = 0;
     105  
     106      for(i = 0; i < referring.length (); i++)
     107        if (referring[i]->use != IPA_REF_ALIAS)
     108  	break;
     109  
     110      return i == 0 ? NULL : referring[i - 1];
     111    }
     112  
     113    /* Return true if the symbol has an alias.  */
     114    bool inline has_aliases_p (void)
     115    {
     116      return first_alias ();
     117    }
     118  
     119    /* Clear reference list.  */
     120    void clear (void)
     121    {
     122      referring.create (0);
     123      references.create (0);
     124    }
     125  
     126    /* Return number of references.  */
     127    unsigned int nreferences (void)
     128    {
     129      return references.length ();
     130    }
     131  
     132    /* Store actual references in references vector.  */
     133    vec<ipa_ref_t, va_heap, vl_ptr> references;
     134    /* Referring is vector of pointers to references.  It must not live in GGC space
     135       or GGC will try to mark middle of references vectors.  */
     136    vec<ipa_ref_t *, va_heap, vl_ptr> referring;
     137  };
     138  
     139  #endif /* GCC_IPA_REF_H */