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                 relocation_class rel_class = (relocation_class)untag_fixnum(array_nth(code_template.untagged(),i));
  32                 relocation_type rel_type = (relocation_type)untag_fixnum(array_nth(code_template.untagged(),i + 1));
  33                 cell offset = array_nth(code_template.untagged(),i + 2);
  34
  35                 relocation_entry new_entry(rel_type,rel_class,code.count + untag_fixnum(offset));
  36                 relocation.append_bytes(&new_entry,sizeof(relocation_entry));
  37         }
  38 }
  39
  40 /* Allocates memory */
  41 void jit::emit(cell code_template_)
  42 {
  43         data_root<array> code_template(code_template_,parent);
  44
  45         emit_relocation(code_template.value());
  46
  47         data_root<byte_array> insns(array_nth(code_template.untagged(),0),parent);
  48
  49         if(computing_offset_p)
  50         {
  51                 cell size = array_capacity(insns.untagged());
  52
  53                 if(offset == 0)
  54                 {
  55                         position--;
  56                         computing_offset_p = false;
  57                 }
  58                 else if(offset < size)
  59                 {
  60                         position++;
  61                         computing_offset_p = false;
  62                 }
  63                 else
  64                         offset -= size;
  65         }
  66
  67         code.append_byte_array(insns.value());
  68 }
  69
  70 void jit::emit_with(cell code_template_, cell argument_) {
  71         data_root<array> code_template(code_template_,parent);
  72         data_root<object> argument(argument_,parent);
  73         literal(argument.value());
  74         emit(code_template.value());
  75 }
  76
  77 void jit::emit_class_lookup(fixnum index, cell type)
  78 {
  79         emit_with(parent->special_objects[PIC_LOAD],tag_fixnum(-index * sizeof(cell)));
  80         emit(parent->special_objects[type]);
  81 }
  82
  83 /* Facility to convert compiled code offsets to quotation offsets.
  84 Call jit_compute_offset() with the compiled code offset, then emit
  85 code, and at the end jit->position is the quotation position. */
  86 void jit::compute_position(cell offset_)
  87 {
  88         computing_offset_p = true;
  89         position = 0;
  90         offset = offset_;
  91 }
  92
  93 /* Allocates memory */
  94 code_block *jit::to_code_block()
  95 {
  96         code.trim();
  97         relocation.trim();
  98         literals.trim();
  99
 100         return parent->add_code_block(
 101                 type,
 102                 code.elements.value(),
 103                 false_object, /* no labels */
 104                 owner.value(),
 105                 relocation.elements.value(),
 106                 literals.elements.value());
 107 }
 108
 109 }