vm/jit.cpp

   1 #include "master.hpp"
   2
   3 namespace factor
   4 {
   5
   6 /* Simple code generator used by:
   7 - profiler (profiler.cpp),
   8 - quotation compiler (quotations.cpp),
   9 - megamorphic caches (dispatch.cpp),
  10 - polymorphic inline caches (inline_cache.cpp) */
  11
  12 /* Allocates memory */
  13 jit::jit(code_block_type type_, cell owner_, factor_vm *vm)
  14         : type(type_),
  15           owner(owner_,vm),
  16           code(vm),
  17           relocation(vm),
  18           literals(vm),
  19           computing_offset_p(false),
  20           position(0),
  21           offset(0),
  22           parent(vm)
  23 {}
  24
  25 void jit::emit_relocation(cell code_template_)
  26 {
  27         data_root<array> code_template(code_template_,parent);
  28         cell capacity = array_capacity(code_template.untagged());
  29         for(cell i = 1; i < capacity; i += 3)
  30         {
  31                 cell rel_class = array_nth(code_template.untagged(),i);
  32                 cell rel_type = array_nth(code_template.untagged(),i + 1);
  33                 cell offset = array_nth(code_template.untagged(),i + 2);
  34
  35                 relocation_entry new_entry(
  36                         (relocation_type)untag_fixnum(rel_type),
  37                         (relocation_class)untag_fixnum(rel_class),
  38                         code.count + untag_fixnum(offset));
  39                 relocation.append_bytes(&new_entry,sizeof(relocation_entry));
  40         }
  41 }
  42
  43 /* Allocates memory */
  44 void jit::emit(cell code_template_)
  45 {
  46         data_root<array> code_template(code_template_,parent);
  47
  48         emit_relocation(code_template.value());
  49
  50         data_root<byte_array> insns(array_nth(code_template.untagged(),0),parent);
  51
  52         if(computing_offset_p)
  53         {
  54                 cell size = array_capacity(insns.untagged());
  55
  56                 if(offset == 0)
  57                 {
  58                         position--;
  59                         computing_offset_p = false;
  60                 }
  61                 else if(offset < size)
  62                 {
  63                         position++;
  64                         computing_offset_p = false;
  65                 }
  66                 else
  67                         offset -= size;
  68         }
  69
  70         code.append_byte_array(insns.value());
  71 }
  72
  73 void jit::emit_with(cell code_template_, cell argument_) {
  74         data_root<array> code_template(code_template_,parent);
  75         data_root<object> argument(argument_,parent);
  76         literal(argument.value());
  77         emit(code_template.value());
  78 }
  79
  80 void jit::emit_class_lookup(fixnum index, cell type)
  81 {
  82         emit_with(parent->special_objects[PIC_LOAD],tag_fixnum(-index * sizeof(cell)));
  83         emit(parent->special_objects[type]);
  84 }
  85
  86 /* Facility to convert compiled code offsets to quotation offsets.
  87 Call jit_compute_offset() with the compiled code offset, then emit
  88 code, and at the end jit->position is the quotation position. */
  89 void jit::compute_position(cell offset_)
  90 {
  91         computing_offset_p = true;
  92         position = 0;
  93         offset = offset_;
  94 }
  95
  96 /* Allocates memory */
  97 code_block *jit::to_code_block()
  98 {
  99         code.trim();
 100         relocation.trim();
 101         literals.trim();
 102
 103         return parent->add_code_block(
 104                 type,
 105                 code.elements.value(),
 106                 false_object, /* no labels */
 107                 owner.value(),
 108                 relocation.elements.value(),
 109                 literals.elements.value());
 110 }
 111
 112 }