5 // Simple non-optimizing compiler.
7 // This is one of the two compilers implementing Factor; the second one is
8 // written in Factor and performs advanced optimizations. See
9 // basis/compiler/compiler.factor.
11 // The non-optimizing compiler compiles a quotation at a time by
12 // concatenating machine code chunks; prolog, epilog, call word, jump to
13 // word, etc. These machine code chunks are generated from Factor code in
14 // basis/bootstrap/assembler/.
16 // Calls to words and constant quotations (referenced by conditionals and
17 // dips) are direct jumps to machine code blocks. Literals are also
18 // referenced directly without going through the literal table.
20 // It actually does do a little bit of very simple optimization:
22 // 1) Tail call optimization.
24 // 2) If a quotation is determined to not call any other words (except for a
25 // few special words which are open-coded, see below), then no prolog/epilog
28 // 3) When in tail position and immediately preceded by literal arguments,
29 // the 'if' is generated inline, instead of as a call to the 'if' word.
31 // 4) When preceded by a quotation, calls to 'dip', '2dip' and '3dip' are
32 // open-coded as retain stack manipulation surrounding a subroutine call.
34 // 5) Sub-primitives are primitive words which are implemented in assembly
35 // and not in the VM. They are open-coded and no subroutine call is generated.
36 // This includes stack shufflers, some fixnum arithmetic words, and words
37 // such as tag, slot and eq?. A primitive call is relatively expensive
38 // (two subroutine calls) so this results in a big speedup for relatively
41 inline cell quotation_jit::nth(cell index) {
42 return array_nth(elements.untagged(), index);
45 void quotation_jit::init_quotation(cell quot) {
46 elements = untag<quotation>(quot)->array;
49 bool quotation_jit::fast_if_p(cell i, cell length) {
50 return (i + 3) == length &&
51 (tagged<object>(array_nth(elements.untagged(), i + 1)).type() == QUOTATION_TYPE) &&
52 array_nth(elements.untagged(), i + 2) == parent->special_objects[JIT_IF_WORD];
55 bool quotation_jit::primitive_call_p(cell i, cell length) {
56 return (i + 2) <= length && array_nth(elements.untagged(), i + 1) ==
57 parent->special_objects[JIT_PRIMITIVE_WORD];
60 bool quotation_jit::fast_dip_p(cell i, cell length) {
61 return (i + 2) <= length && array_nth(elements.untagged(), i + 1) ==
62 parent->special_objects[JIT_DIP_WORD];
65 bool quotation_jit::fast_2dip_p(cell i, cell length) {
66 return (i + 2) <= length && array_nth(elements.untagged(), i + 1) ==
67 parent->special_objects[JIT_2DIP_WORD];
70 bool quotation_jit::fast_3dip_p(cell i, cell length) {
71 return (i + 2) <= length && array_nth(elements.untagged(), i + 1) ==
72 parent->special_objects[JIT_3DIP_WORD];
75 bool quotation_jit::declare_p(cell i, cell length) {
76 return (i + 2) <= length && array_nth(elements.untagged(), i + 1) ==
77 parent->special_objects[JIT_DECLARE_WORD];
81 bool quotation_jit::mega_lookup_p(cell i, cell length) {
82 return (i + 4) <= length &&
83 (tagged<object>(array_nth(elements.untagged(), i + 1)).type() == FIXNUM_TYPE) &&
84 (tagged<object>(array_nth(elements.untagged(), i + 2)).type() == ARRAY_TYPE) &&
85 array_nth(elements.untagged(), i + 3) == parent->special_objects[MEGA_LOOKUP_WORD];
88 // Subprimitives should be flagged with whether they require a stack frame.
90 bool quotation_jit::special_subprimitive_p(cell obj) {
91 return obj == parent->special_objects[SIGNAL_HANDLER_WORD] ||
92 obj == parent->special_objects[LEAF_SIGNAL_HANDLER_WORD] ||
93 obj == parent->special_objects[UNWIND_NATIVE_FRAMES_WORD];
96 // All quotations wants a stack frame, except if they contain:
97 // 1) calls to the special subprimitives, see #295.
98 // 2) mega cache lookups, see #651
99 bool quotation_jit::stack_frame_p() {
100 cell length = array_capacity(elements.untagged());
101 for (cell i = 0; i < length; i++) {
102 cell obj = array_nth(elements.untagged(), i);
103 cell tag = tagged<object>(obj).type();
104 if ((tag == WORD_TYPE && special_subprimitive_p(obj)) ||
105 (tag == ARRAY_TYPE && mega_lookup_p(i, length)))
111 static bool trivial_quotation_p(array* elements) {
112 return array_capacity(elements) == 1 &&
113 TAG(array_nth(elements, 0)) == WORD_TYPE;
116 // Allocates memory (emit)
117 void quotation_jit::emit_epilog(bool needed) {
119 emit(parent->special_objects[JIT_SAFEPOINT]);
120 emit(parent->special_objects[JIT_EPILOG]);
124 // Allocates memory conditionally
125 void quotation_jit::emit_quotation(cell quot_) {
126 data_root<quotation> quot(quot_, parent);
128 array* elements = untag<array>(quot->array);
130 // If the quotation consists of a single word, compile a direct call
132 if (trivial_quotation_p(elements))
133 literal(array_nth(elements, 0));
136 parent->jit_compile_quotation(quot.value(), relocate);
137 literal(quot.value());
141 // Allocates memory (parameter(), literal(), emit_epilog, emit_with_literal)
142 void quotation_jit::iterate_quotation() {
143 bool stack_frame = stack_frame_p();
148 emit(parent->special_objects[JIT_SAFEPOINT]);
149 emit(parent->special_objects[JIT_PROLOG]);
152 cell length = array_capacity(elements.untagged());
153 bool tail_call = false;
155 for (cell i = 0; i < length; i++) {
157 data_root<object> obj(nth(i), parent);
159 switch (obj.type()) {
162 if (to_boolean(obj.as<word>()->subprimitive)) {
163 tail_call = emit_subprimitive(obj.value(), // word
164 i == length - 1, // tail_call_p
165 stack_frame); // stack_frame_p
167 else if (i == length - 1) {
168 emit_epilog(stack_frame);
170 word_jump(obj.value());
172 word_call(obj.value());
175 push(obj.as<wrapper>()->object);
177 case BYTE_ARRAY_TYPE:
179 if (primitive_call_p(i, length)) {
180 // On x86-64 and PowerPC, the VM pointer is stored in a register;
181 // on other platforms, the RT_VM relocation is used and it needs
182 // an offset parameter
184 parameter(tag_fixnum(0));
186 parameter(obj.value());
187 parameter(false_object);
188 #ifdef FACTOR_PPC_TOC
189 parameter(obj.value());
190 parameter(false_object);
192 emit(parent->special_objects[JIT_PRIMITIVE]);
199 // 'if' preceded by two literal quotations (this is why if and ? are
200 // mutually recursive in the library, but both still work)
201 if (fast_if_p(i, length)) {
202 emit_epilog(stack_frame);
204 emit_quotation(nth(i));
205 emit_quotation(nth(i + 1));
206 emit(parent->special_objects[JIT_IF]);
209 else if (fast_dip_p(i, length)) {
210 emit_quotation(obj.value());
211 emit(parent->special_objects[JIT_DIP]);
214 else if (fast_2dip_p(i, length)) {
215 emit_quotation(obj.value());
216 emit(parent->special_objects[JIT_2DIP]);
219 else if (fast_3dip_p(i, length)) {
220 emit_quotation(obj.value());
221 emit(parent->special_objects[JIT_3DIP]);
228 if (mega_lookup_p(i, length)) {
230 emit_mega_cache_lookup(nth(i), untag_fixnum(nth(i + 1)), nth(i + 2));
232 } // Non-optimizing compiler ignores declarations
233 else if (declare_p(i, length))
245 set_position(length);
246 emit_epilog(stack_frame);
247 emit(parent->special_objects[JIT_RETURN]);
251 cell quotation_jit::word_stack_frame_size(cell obj) {
252 if (special_subprimitive_p(obj))
253 return SIGNAL_HANDLER_STACK_FRAME_SIZE;
254 return JIT_FRAME_SIZE;
258 void quotation_jit::emit_mega_cache_lookup(cell methods_, fixnum index,
260 data_root<array> methods(methods_, parent);
261 data_root<array> cache(cache_, parent);
263 // Load the object from the datastack.
264 emit_with_literal(parent->special_objects[PIC_LOAD],
265 tag_fixnum(-index * sizeof(cell)));
267 // Do a cache lookup.
268 emit_with_literal(parent->special_objects[MEGA_LOOKUP], cache.value());
270 // If we end up here, the cache missed.
271 emit(parent->special_objects[JIT_PROLOG]);
273 // Push index, method table and cache on the stack.
274 push(methods.value());
275 push(tag_fixnum(index));
277 word_call(parent->special_objects[MEGA_MISS_WORD]);
279 // Now the new method has been stored into the cache, and its on
281 emit(parent->special_objects[JIT_EPILOG]);
282 emit(parent->special_objects[JIT_EXECUTE]);
286 code_block* factor_vm::jit_compile_quotation(cell owner_, cell quot_,
288 data_root<object> owner(owner_, this);
289 data_root<quotation> quot(quot_, this);
291 quotation_jit compiler(owner.value(), true, relocating, this);
292 compiler.init_quotation(quot.value());
293 compiler.iterate_quotation();
295 cell frame_size = compiler.word_stack_frame_size(owner_);
297 code_block* compiled = compiler.to_code_block(CODE_BLOCK_UNOPTIMIZED,
300 initialize_code_block(compiled);
306 void factor_vm::jit_compile_quotation(cell quot_, bool relocating) {
307 data_root<quotation> quot(quot_, this);
308 if (!quotation_compiled_p(quot.untagged())) {
309 code_block* compiled =
310 jit_compile_quotation(quot.value(), quot.value(), relocating);
311 quot.untagged()->entry_point = compiled->entry_point();
316 void factor_vm::primitive_jit_compile() {
317 jit_compile_quotation(ctx->pop(), true);
320 cell factor_vm::lazy_jit_compile_entry_point() {
321 return untag<word>(special_objects[LAZY_JIT_COMPILE_WORD])->entry_point;
324 // push a new quotation on the stack
326 void factor_vm::primitive_array_to_quotation() {
327 quotation* quot = allot<quotation>(sizeof(quotation));
329 quot->array = ctx->peek();
330 quot->cached_effect = false_object;
331 quot->cache_counter = false_object;
332 quot->entry_point = lazy_jit_compile_entry_point();
334 ctx->replace(tag<quotation>(quot));
337 // Allocates memory (from_unsigned_cell)
338 void factor_vm::primitive_quotation_code() {
339 data_root<quotation> quot(ctx->pop(), this);
341 ctx->push(from_unsigned_cell(quot->entry_point));
342 ctx->push(from_unsigned_cell((cell)quot->code() + quot->code()->size()));
346 fixnum factor_vm::quot_code_offset_to_scan(cell quot_, cell offset) {
347 data_root<quotation> quot(quot_, this);
348 data_root<array> array(quot->array, this);
350 quotation_jit compiler(quot.value(), false, false, this);
351 compiler.init_quotation(quot.value());
352 compiler.compute_position(offset);
353 compiler.iterate_quotation();
355 return compiler.get_position();
359 cell factor_vm::lazy_jit_compile(cell quot_) {
360 data_root<quotation> quot(quot_, this);
362 FACTOR_ASSERT(!quotation_compiled_p(quot.untagged()));
364 code_block* compiled =
365 jit_compile_quotation(quot.value(), quot.value(), true);
366 quot.untagged()->entry_point = compiled->entry_point();
372 VM_C_API cell lazy_jit_compile(cell quot, factor_vm* parent) {
373 return parent->lazy_jit_compile(quot);
376 bool factor_vm::quotation_compiled_p(quotation* quot) {
377 return quot->entry_point != 0 &&
378 quot->entry_point != lazy_jit_compile_entry_point();
381 void factor_vm::primitive_quotation_compiled_p() {
382 quotation* quot = untag_check<quotation>(ctx->pop());
383 ctx->push(tag_boolean(quotation_compiled_p(quot)));