gcc/context.h

   1 /* context.h - Holder for global state
   2    Copyright (C) 2013 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef GCC_CONTEXT_H
  21 #define GCC_CONTEXT_H
  22
  23 namespace gcc {
  24
  25 class pass_manager;
  26
  27 /* GCC's internal state can be divided into zero or more
  28    "parallel universe" of state; an instance of this class is one such
  29    context of state.  */
  30 class GTY((user)) context
  31 {
  32 public:
  33   /* Ensure that instances are allocated within the GC-heap.  */
  34   void *operator new (std::size_t size);
  35
  36   context();
  37
  38   /* Garbage-collector integration.
  39
  40      Each context assumes it has full control of the GC-heap that it
  41      is associated with.  It acts as a root for that GC-heap, owning
  42      references to within it.
  43
  44      Note that context instances are allocated within their own GC
  45      heap.
  46
  47      The methods are called the *first time* that the context is reached
  48      during a ggc/pch traversal, rather than every time.  */
  49
  50   void gt_ggc_mx ();
  51   void gt_pch_nx ();
  52   void gt_pch_nx (gt_pointer_operator op, void *cookie);
  53
  54   /* Pass-management.  */
  55
  56   pass_manager *get_passes () { gcc_assert (passes_); return passes_; }
  57
  58 private:
  59   /* Pass-management.  */
  60   pass_manager *passes_;
  61
  62 }; // class context
  63
  64 } // namespace gcc
  65
  66 /* The global singleton context aka "g".
  67    (the name is chosen to be easy to type in a debugger).  */
  68 extern GTY(()) gcc::context *g;
  69
  70 /* Global hooks for ggc/pch.
  71
  72    The gcc::context class is marked with GTY((user)), which leads to
  73    gengtype creating autogenerated functions for handling context within
  74    gtype-desc.c:
  75
  76      void gt_ggc_mx_context (void *x_p);
  77      void gt_pch_nx_context (void *x_p)
  78      void gt_pch_p_7context (void *this_obj,
  79                              void *x_p,
  80                              gt_pointer_operator op,
  81                              void *cookie);
  82
  83    Those functions call the following global functions the first time
  84    that the context is reached during a traversal, and the following
  85    global functions in turn simply call the corresponding  methods of the
  86    context (so that they can access private fields of the context).  */
  87
  88 inline void
  89 gt_ggc_mx (gcc::context *ctxt)
  90 {
  91   ctxt->gt_ggc_mx ();
  92 }
  93
  94 inline void
  95 gt_pch_nx (gcc::context *ctxt)
  96 {
  97   ctxt->gt_pch_nx ();
  98 }
  99
 100 inline void
 101 gt_pch_nx (gcc::context *ctxt, gt_pointer_operator op, void *cookie)
 102 {
 103   ctxt->gt_pch_nx (op, cookie);
 104 }
 105
 106 #endif /* ! GCC_CONTEXT_H */