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           parameters(vm),
  19           literals(vm),
  20           computing_offset_p(false),
  21           position(0),
  22           offset(0),
  23           parent(vm)
  24 {}
  25
  26 void jit::emit_relocation(cell code_template_)
  27 {
  28         data_root<array> code_template(code_template_,parent);
  29         cell capacity = array_capacity(code_template.untagged());
  30         for(cell i = 1; i < capacity; i += 3)
  31         {
  32                 relocation_class rel_class = (relocation_class)untag_fixnum(array_nth(code_template.untagged(),i));
  33                 relocation_type rel_type = (relocation_type)untag_fixnum(array_nth(code_template.untagged(),i + 1));
  34                 cell offset = array_nth(code_template.untagged(),i + 2);
  35
  36                 relocation_entry new_entry(rel_type,rel_class,code.count + untag_fixnum(offset));
  37                 relocation.append_bytes(&new_entry,sizeof(relocation_entry));
  38         }
  39 }
  40
  41 /* Allocates memory */
  42 void jit::emit(cell code_template_)
  43 {
  44         data_root<array> code_template(code_template_,parent);
  45
  46         emit_relocation(code_template.value());
  47
  48         data_root<byte_array> insns(array_nth(code_template.untagged(),0),parent);
  49
  50         if(computing_offset_p)
  51         {
  52                 cell size = array_capacity(insns.untagged());
  53
  54                 if(offset == 0)
  55                 {
  56                         position--;
  57                         computing_offset_p = false;
  58                 }
  59                 else if(offset < size)
  60                 {
  61                         position++;
  62                         computing_offset_p = false;
  63                 }
  64                 else
  65                         offset -= size;
  66         }
  67
  68         code.append_byte_array(insns.value());
  69 }
  70
  71 void jit::emit_with_literal(cell code_template_, cell argument_) {
  72         data_root<array> code_template(code_template_,parent);
  73         data_root<object> argument(argument_,parent);
  74         literal(argument.value());
  75         emit(code_template.value());
  76 }
  77
  78 void jit::emit_with_parameter(cell code_template_, cell argument_) {
  79         data_root<array> code_template(code_template_,parent);
  80         data_root<object> argument(argument_,parent);
  81         parameter(argument.value());
  82         emit(code_template.value());
  83 }
  84
  85 void jit::emit_class_lookup(fixnum index, cell type)
  86 {
  87         emit_with_literal(parent->special_objects[PIC_LOAD],tag_fixnum(-index * sizeof(cell)));
  88         emit(parent->special_objects[type]);
  89 }
  90
  91 /* Facility to convert compiled code offsets to quotation offsets.
  92 Call jit_compute_offset() with the compiled code offset, then emit
  93 code, and at the end jit->position is the quotation position. */
  94 void jit::compute_position(cell offset_)
  95 {
  96         computing_offset_p = true;
  97         position = 0;
  98         offset = offset_;
  99 }
 100
 101 /* Allocates memory */
 102 code_block *jit::to_code_block()
 103 {
 104         code.trim();
 105         relocation.trim();
 106         parameters.trim();
 107         literals.trim();
 108
 109         return parent->add_code_block(
 110                 type,
 111                 code.elements.value(),
 112                 false_object, /* no labels */
 113                 owner.value(),
 114                 relocation.elements.value(),
 115                 parameters.elements.value(),
 116                 literals.elements.value());
 117 }
 118
 119 }