Algol 68 Genie

parser-annotate.c

     
   1  //! @file parser-annotate.c
   2  //! @author J. Marcel van der Veer
   3  
   4  //! @section Copyright
   5  //!
   6  //! This file is part of Algol68G - an Algol 68 compiler-interpreter.
   7  //! Copyright 2001-2025 J. Marcel van der Veer [algol68g@xs4all.nl].
   8  
   9  //! @section License
  10  //!
  11  //! This program is free software; you can redistribute it and/or modify it 
  12  //! under the terms of the GNU General Public License as published by the 
  13  //! Free Software Foundation; either version 3 of the License, or 
  14  //! (at your option) any later version.
  15  //!
  16  //! This program is distributed in the hope that it will be useful, but 
  17  //! WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
  18  //! or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 
  19  //! more details. You should have received a copy of the GNU General Public 
  20  //! License along with this program. If not, see [http://www.gnu.org/licenses/].
  21  
  22  //! @section Synopsis
  23  //!
  24  //! Annotate syntax tree.
  25  
  26  #include "a68g.h"
  27  #include "a68g-defines.h"
  28  #include "a68g-parser.h"
  29  #include "a68g-prelude.h"
  30  
  31  // The A68G GC cannot walk the expression stack, which holds no mode info.
  32  // En lieu, all units yielding a value with mode that needs colouring
  33  // copy the top-of-stack to an anonymous variable in the frame stack.
  34  //
  35  // TODO: Optimize this code as some tags are placed without need. 
  36  //       For instance, not all REFs point to the heap.
  37  
  38  //! @brief Test whether unit is an identifier (primary).
  39  
  40  BOOL_T identifier_gc (NODE_T *p)
  41  {
  42    switch (ATTRIBUTE (p))
  43    {
  44      case UNIT:
  45      case TERTIARY:
  46      case SECONDARY:
  47      case PRIMARY:
  48        return identifier_gc (SUB (p));
  49      case IDENTIFIER:
  50        return TAX (p) != NO_TAG;
  51      default:
  52        return A68G_FALSE;
  53    }
  54  }
  55  
  56  //! @brief Annotate syntax tree for GC.
  57  
  58  void annotate_gc_identity_declaration (NODE_T *p)
  59  {
  60    if (p != NO_NODE) {
  61      switch (ATTRIBUTE (p)) {
  62      case DECLARER: {
  63          annotate_gc (SUB (p));
  64          annotate_gc_identity_declaration (NEXT (p));
  65          return;
  66        }
  67      case DEFINING_IDENTIFIER: {
  68  // Do not tag the unit, value will already be in the frame stack.
  69          annotate_gc (SUB (NEXT_NEXT (p)));
  70          return;
  71        }
  72      }
  73    }
  74  }
  75  
  76  //! @brief Annotate syntax tree for GC.
  77  
  78  void annotate_gc_variable_declaration (NODE_T * p)
  79  {
  80    if (p != NO_NODE) {
  81      switch (ATTRIBUTE (p)) {
  82      case DECLARER: {
  83          annotate_gc (SUB (p));
  84          annotate_gc_variable_declaration (NEXT (p));
  85          return;
  86        }
  87      case DEFINING_IDENTIFIER: {
  88          if (whether (p, DEFINING_IDENTIFIER, ASSIGN_SYMBOL, UNIT, STOP)) {
  89  // Do not tag the unit, value will already be in the frame stack.
  90            annotate_gc (SUB (NEXT_NEXT (p)));
  91            return;
  92          }
  93        }
  94      }
  95    }
  96  }
  97  
  98  //! @brief Annotate syntax tree for GC.
  99  
 100  void annotate_gc (NODE_T *p)
 101  {
 102    for (; p != NO_NODE; FORWARD (p)) {
 103      if (ATTRIBUTE (p) == UNIT) {
 104        MOID_T *m = MOID (p);
 105        if (identifier_gc (p)) {
 106          /* Value already in the frame stack */;
 107        } else if (moid_needs_colouring (m)) {
 108          TAG_T *z = add_tag (TABLE (p), ANONYMOUS, p, MOID (p), UNIT);
 109          TAX_GC (p) = z;
 110          HEAP (z) = LOC_SYMBOL;
 111          USE (z) = A68G_TRUE;
 112        }
 113        annotate_gc (SUB (p));
 114      } else if (ATTRIBUTE (p) == IDENTITY_DECLARATION) {
 115        annotate_gc_identity_declaration (SUB (p));
 116      } else if (ATTRIBUTE (p) == VARIABLE_DECLARATION) {
 117        annotate_gc_variable_declaration (SUB (p));
 118      } else if (SUB (p) != NO_NODE) {
 119        annotate_gc (SUB (p));
 120      }
 121    }
 122  }
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