steve
/
factor
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

VM: omit the type check if checking for fixnum and it's the first check 

Previously: and ecx, 0xf ; cmp ecx, 0 ; jz <address> was generated. Now
instead: and ecx, 0xf ; jz <address> because the cmp, ecx, 0 instruction
is redundant.
locals-and-roots
Björn Lindqvist 2016-05-30 23:54:26 +02:00
parent 59443dca01
commit dae2229957
1 changed files with 14 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
vm/inline_cache.cpp
View File

@ -40,17 +40,10 @@ struct inline_cache_jit : public jit {
: jit(code_block_pic, generic_word, vm) {}
;
void emit_check(cell klass);
void compile_inline_cache(fixnum index, cell generic_word_, cell methods_,
cell cache_entries_, bool tail_call_p);
};
/* Allocates memory */
void inline_cache_jit::emit_check(cell klass) {
cell i = TAG(klass) == FIXNUM_TYPE ? PIC_CHECK_TAG : PIC_CHECK_TUPLE;
emit_with_literal(parent->special_objects[i], klass);
}
/* index: 0 = top of stack, 1 = item underneath, etc
cache_entries: array of class/method pairs */
/* Allocates memory */
@ -68,6 +61,8 @@ void inline_cache_jit::compile_inline_cache(fixnum index, cell generic_word_,
/* Generate machine code to determine the object's class. */
emit_with_literal(parent->special_objects[PIC_LOAD],
tag_fixnum(-index * sizeof(cell)));
/* Put the tag of the object, or class of the tuple in a register. */
emit(parent->special_objects[inline_cache_type]);
/* Generate machine code to check, in turn, if the class is one of the cached
@ -75,7 +70,18 @@ void inline_cache_jit::compile_inline_cache(fixnum index, cell generic_word_,
for (cell i = 0; i < array_capacity(cache_entries.untagged()); i += 2) {
/* Class equal? */
cell klass = array_nth(cache_entries.untagged(), i);
emit_check(klass);
cell check_type = PIC_CHECK_TAG;
if (TAG(klass) != FIXNUM_TYPE)
check_type = PIC_CHECK_TUPLE;
/* The tag check can be skipped if it is the first one and we are
checking for the fixnum type which is 0. That is because the
AND instruction in the PIC_TAG template already sets the zero
flag. */
if (i > 0 || inline_cache_type == PIC_TUPLE || klass > 0) {
emit_with_literal(parent->special_objects[check_type], klass);
}
/* Yes? Jump to method */
cell method = array_nth(cache_entries.untagged(), i + 1);