vm/jit.cpp

   1 #include "master.hpp"
   2
   3 namespace factor {
   4
   5 // Simple code generator used by:
   6 // - quotation compiler (quotations.cpp),
   7 // - megamorphic caches (dispatch.cpp),
   8 // - polymorphic inline caches (inline_cache.cpp)
   9
  10 // Allocates memory (`code` and `relocation` initializers create
  11 // growable_byte_array)
  12 jit::jit(cell owner, factor_vm* vm)
  13     : owner(owner, vm),
  14       code(vm),
  15       relocation(vm),
  16       parameters(vm),
  17       literals(vm),
  18       computing_offset_p(false),
  19       position(0),
  20       offset(0),
  21       parent(vm) {
  22   fixnum old_count = atomic::fetch_add(&parent->current_jit_count, 1);
  23   FACTOR_ASSERT(old_count >= 0);
  24   (void)old_count;
  25 }
  26
  27 jit::~jit() {
  28   fixnum old_count = atomic::fetch_subtract(&parent->current_jit_count, 1);
  29   FACTOR_ASSERT(old_count >= 1);
  30   (void)old_count;
  31 }
  32
  33 // Allocates memory
  34 void jit::emit_relocation(cell relocation_template_) {
  35   data_root<byte_array> relocation_template(relocation_template_, parent);
  36   cell capacity =
  37       array_capacity(relocation_template.untagged()) / sizeof(relocation_entry);
  38   relocation_entry* relocations = relocation_template->data<relocation_entry>();
  39   for (cell i = 0; i < capacity; i++) {
  40     relocation_entry entry = relocations[i];
  41     relocation_entry new_entry(entry.type(), entry.klass(),
  42                                entry.offset() + code.count);
  43     relocation.append_bytes(&new_entry, sizeof(relocation_entry));
  44   }
  45 }
  46
  47 // Allocates memory
  48 void jit::emit(cell code_template_) {
  49   data_root<array> code_template(code_template_, parent);
  50
  51   emit_relocation(array_nth(code_template.untagged(), 0));
  52
  53   data_root<byte_array> insns(array_nth(code_template.untagged(), 1), parent);
  54
  55   if (computing_offset_p) {
  56     cell size = array_capacity(insns.untagged());
  57
  58     if (offset == 0) {
  59       position--;
  60       computing_offset_p = false;
  61     } else if (offset < size) {
  62       position++;
  63       computing_offset_p = false;
  64     } else
  65       offset -= size;
  66   }
  67
  68   code.append_byte_array(insns.value());
  69 }
  70
  71 // Allocates memory
  72 void jit::emit_with_literal(cell code_template_, cell argument_) {
  73   data_root<array> code_template(code_template_, parent);
  74   data_root<object> argument(argument_, parent);
  75   literal(argument.value());
  76   emit(code_template.value());
  77 }
  78
  79 // Allocates memory
  80 void jit::emit_with_parameter(cell code_template_, cell argument_) {
  81   data_root<array> code_template(code_template_, parent);
  82   data_root<object> argument(argument_, parent);
  83   parameter(argument.value());
  84   emit(code_template.value());
  85 }
  86
  87 // Allocates memory
  88 bool jit::emit_subprimitive(cell word_, bool tail_call_p, bool stack_frame_p) {
  89   data_root<word> word(word_, parent);
  90   data_root<array> code_template(word->subprimitive, parent);
  91   parameters.append(untag<array>(array_nth(code_template.untagged(), 0)));
  92   literals.append(untag<array>(array_nth(code_template.untagged(), 1)));
  93   emit(array_nth(code_template.untagged(), 2));
  94
  95   if (array_capacity(code_template.untagged()) == 5) {
  96     if (tail_call_p) {
  97       if (stack_frame_p)
  98         emit(parent->special_objects[JIT_EPILOG]);
  99       emit(array_nth(code_template.untagged(), 4));
 100       return true;
 101     } else
 102       emit(array_nth(code_template.untagged(), 3));
 103   }
 104   return false;
 105 }
 106
 107 // Facility to convert compiled code offsets to quotation offsets.
 108 // Call jit_compute_offset() with the compiled code offset, then emit
 109 // code, and at the end jit->position is the quotation position.
 110 void jit::compute_position(cell offset_) {
 111   computing_offset_p = true;
 112   position = 0;
 113   offset = offset_;
 114 }
 115
 116 // Allocates memory (trim(), add_code_block)
 117 code_block* jit::to_code_block(code_block_type type, cell frame_size) {
 118   // Emit dummy GC info
 119   code.grow_bytes(alignment_for(code.count + 4, data_alignment));
 120   uint32_t dummy_gc_info = 0;
 121   code.append_bytes(&dummy_gc_info, sizeof(uint32_t));
 122
 123   code.trim();
 124   relocation.trim();
 125   parameters.trim();
 126   literals.trim();
 127
 128   return parent->add_code_block(
 129       type, code.elements.value(), false_object, // no labels
 130       owner.value(), relocation.elements.value(), parameters.elements.value(),
 131       literals.elements.value(), frame_size);
 132 }
 133
 134 }