void inline_cache_jit::emit_check(cell klass)
{
cell code_template;
if(TAG(klass) == FIXNUM_TYPE && untag_fixnum(klass) < HEADER_TYPE)
code_template = parent->userenv[PIC_CHECK_TAG];
else
code_template = parent->userenv[PIC_CHECK];
emit_with(code_template,klass);
}
/* index: 0 = top of stack, 1 = item underneath, etc
cache_entries: array of class/method pairs */
void inline_cache_jit::compile_inline_cache(fixnum index,
cell generic_word_,
cell methods_,
cell cache_entries_,
bool tail_call_p)
{
gc_root<word> generic_word(generic_word_,parent);
gc_root<array> methods(methods_,parent);
gc_root<array> cache_entries(cache_entries_,parent);
cell inline_cache_type = parent->determine_inline_cache_type(cache_entries.untagged());
parent->update_pic_count(inline_cache_type);
/* Generate machine code to determine the object's class. */
emit_class_lookup(index,inline_cache_type);
/* Generate machine code to check, in turn, if the class is one of the cached entries. */
cell i;
for(i = 0; i < array_capacity(cache_entries.untagged()); i += 2)
{
/* Class equal? */
cell klass = array_nth(cache_entries.untagged(),i);
emit_check(klass);
/* Yes? Jump to method */
cell method = array_nth(cache_entries.untagged(),i + 1);
emit_with(parent->userenv[PIC_HIT],method);
}
/* Generate machine code to handle a cache miss, which ultimately results in
this function being called again.
The inline-cache-miss primitive call receives enough information to
reconstruct the PIC. */
push(generic_word.value());
push(methods.value());
push(tag_fixnum(index));
push(cache_entries.value());
word_special(parent->userenv[tail_call_p ? PIC_MISS_TAIL_WORD : PIC_MISS_WORD]);
}
void word_special(cell word) {
emit_with(parent->userenv[JIT_WORD_SPECIAL],word);
}
void word_call(cell word) {
emit_with(parent->userenv[JIT_WORD_CALL],word);
}
void push(cell literal) {
emit_with(parent->userenv[JIT_PUSH_IMMEDIATE],literal);
}
void jit::emit_class_lookup(fixnum index, cell type)
{
emit_with(parent_vm->userenv[PIC_LOAD],tag_fixnum(-index * sizeof(cell)));
emit(parent_vm->userenv[type]);
}