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