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.set_value(untag<quotation>(quot)->array);
49 bool quotation_jit::fast_if_p(cell i, cell length) {
50 return (i + 3) == length &&
51 TAG(nth(i + 1)) == QUOTATION_TYPE &&
52 nth(i + 2) == parent->special_objects[JIT_IF_WORD];
55 bool quotation_jit::primitive_call_p(cell i, cell length) {
56 cell jit_primitive_word = parent->special_objects[JIT_PRIMITIVE_WORD];
57 return (i + 2) <= length && nth(i + 1) == jit_primitive_word;
60 bool quotation_jit::fast_dip_p(cell i, cell length) {
61 cell jit_dip_word = parent->special_objects[JIT_DIP_WORD];
62 return (i + 2) <= length && nth(i + 1) == jit_dip_word;
65 bool quotation_jit::fast_2dip_p(cell i, cell length) {
66 cell jit_2dip_word = parent->special_objects[JIT_2DIP_WORD];
67 return (i + 2) <= length && nth(i + 1) == jit_2dip_word;
70 bool quotation_jit::fast_3dip_p(cell i, cell length) {
71 cell jit_3dip_word = parent->special_objects[JIT_3DIP_WORD];
72 return (i + 2) <= length && nth(i + 1) == jit_3dip_word;
75 bool quotation_jit::declare_p(cell i, cell length) {
76 cell jit_declare_word = parent->special_objects[JIT_DECLARE_WORD];
77 return (i + 2) <= length && nth(i + 1) == jit_declare_word;
80 bool quotation_jit::mega_lookup_p(cell i, cell length) {
81 return (i + 4) <= length &&
82 TAG(nth(i + 1)) == FIXNUM_TYPE &&
83 TAG(nth(i + 2)) == ARRAY_TYPE &&
84 nth(i + 3) == parent->special_objects[MEGA_LOOKUP_WORD];
87 // Subprimitives should be flagged with whether they require a stack frame.
89 bool quotation_jit::special_subprimitive_p(cell obj) {
90 return obj == parent->special_objects[SIGNAL_HANDLER_WORD] ||
91 obj == parent->special_objects[LEAF_SIGNAL_HANDLER_WORD] ||
92 obj == parent->special_objects[UNWIND_NATIVE_FRAMES_WORD];
95 // All quotations wants a stack frame, except if they contain:
96 // 1) calls to the special subprimitives, see #295.
97 // 2) mega cache lookups, see #651
98 bool quotation_jit::stack_frame_p() {
99 cell length = array_capacity(elements.untagged());
100 for (cell i = 0; i < length; i++) {
103 if ((tag == WORD_TYPE && special_subprimitive_p(obj)) ||
104 (tag == ARRAY_TYPE && mega_lookup_p(i, length)))
110 static bool trivial_quotation_p(array* elements) {
111 return array_capacity(elements) == 1 &&
112 TAG(array_nth(elements, 0)) == WORD_TYPE;
115 // Allocates memory (emit)
116 void quotation_jit::emit_epilog(bool needed) {
118 emit(parent->special_objects[JIT_SAFEPOINT]);
119 emit(parent->special_objects[JIT_EPILOG]);
123 // Allocates memory conditionally
124 void quotation_jit::emit_quotation(cell quot_) {
125 data_root<quotation> quot(quot_, parent);
127 array* elements = untag<array>(quot->array);
129 // If the quotation consists of a single word, compile a direct call
131 if (trivial_quotation_p(elements))
132 literal(array_nth(elements, 0));
135 parent->jit_compile_quotation(quot.value(), relocate);
136 literal(quot.value());
140 // Allocates memory (parameter(), literal(), emit_epilog, emit_with_literal)
141 void quotation_jit::iterate_quotation() {
142 bool stack_frame = stack_frame_p();
147 emit(parent->special_objects[JIT_SAFEPOINT]);
148 emit(parent->special_objects[JIT_PROLOG]);
151 cell length = array_capacity(elements.untagged());
152 bool tail_call = false;
154 for (cell i = 0; i < length; i++) {
156 data_root<object> obj(nth(i), parent);
158 switch (obj.type()) {
161 if (to_boolean(obj.as<word>()->subprimitive)) {
162 tail_call = emit_subprimitive(obj.value(), // word
163 i == length - 1, // tail_call_p
164 stack_frame); // stack_frame_p
166 else if (i == length - 1) {
167 emit_epilog(stack_frame);
169 word_jump(obj.value());
171 word_call(obj.value());
174 push(obj.as<wrapper>()->object);
176 case BYTE_ARRAY_TYPE:
178 if (primitive_call_p(i, length)) {
179 // On x86-64 and PowerPC, the VM pointer is stored in a register;
180 // on other platforms, the RT_VM relocation is used and it needs
181 // an offset parameter
183 parameter(tag_fixnum(0));
185 parameter(obj.value());
186 parameter(false_object);
187 #ifdef FACTOR_PPC_TOC
188 parameter(obj.value());
189 parameter(false_object);
191 emit(parent->special_objects[JIT_PRIMITIVE]);
198 // 'if' preceded by two literal quotations (this is why if and ? are
199 // mutually recursive in the library, but both still work)
200 if (fast_if_p(i, length)) {
201 emit_epilog(stack_frame);
203 emit_quotation(nth(i));
204 emit_quotation(nth(i + 1));
205 emit(parent->special_objects[JIT_IF]);
208 else if (fast_dip_p(i, length)) {
209 emit_quotation(obj.value());
210 emit(parent->special_objects[JIT_DIP]);
213 else if (fast_2dip_p(i, length)) {
214 emit_quotation(obj.value());
215 emit(parent->special_objects[JIT_2DIP]);
218 else if (fast_3dip_p(i, length)) {
219 emit_quotation(obj.value());
220 emit(parent->special_objects[JIT_3DIP]);
227 if (mega_lookup_p(i, length)) {
229 emit_mega_cache_lookup(nth(i), untag_fixnum(nth(i + 1)), nth(i + 2));
231 } // Non-optimizing compiler ignores declarations
232 else if (declare_p(i, length))
244 set_position(length);
245 emit_epilog(stack_frame);
246 emit(parent->special_objects[JIT_RETURN]);
250 cell quotation_jit::word_stack_frame_size(cell obj) {
251 if (special_subprimitive_p(obj))
252 return SIGNAL_HANDLER_STACK_FRAME_SIZE;
253 return JIT_FRAME_SIZE;
257 void quotation_jit::emit_mega_cache_lookup(cell methods_, fixnum index,
259 data_root<array> methods(methods_, parent);
260 data_root<array> cache(cache_, parent);
262 // Load the object from the datastack.
263 emit_with_literal(parent->special_objects[PIC_LOAD],
264 tag_fixnum(-index * sizeof(cell)));
266 // Do a cache lookup.
267 emit_with_literal(parent->special_objects[MEGA_LOOKUP], cache.value());
269 // If we end up here, the cache missed.
270 emit(parent->special_objects[JIT_PROLOG]);
272 // Push index, method table and cache on the stack.
273 push(methods.value());
274 push(tag_fixnum(index));
276 word_call(parent->special_objects[MEGA_MISS_WORD]);
278 // Now the new method has been stored into the cache, and its on
280 emit(parent->special_objects[JIT_EPILOG]);
281 emit(parent->special_objects[JIT_EXECUTE]);
285 code_block* factor_vm::jit_compile_quotation(cell owner_, cell quot_,
287 data_root<object> owner(owner_, this);
288 data_root<quotation> quot(quot_, this);
290 quotation_jit compiler(owner.value(), true, relocating, this);
291 compiler.init_quotation(quot.value());
292 compiler.iterate_quotation();
294 cell frame_size = compiler.word_stack_frame_size(owner_);
296 code_block* compiled = compiler.to_code_block(CODE_BLOCK_UNOPTIMIZED,
299 initialize_code_block(compiled);
305 void factor_vm::jit_compile_quotation(cell quot_, bool relocating) {
306 data_root<quotation> quot(quot_, this);
307 if (!quotation_compiled_p(quot.untagged())) {
308 code_block* compiled =
309 jit_compile_quotation(quot.value(), quot.value(), relocating);
310 quot.untagged()->entry_point = compiled->entry_point();
315 void factor_vm::primitive_jit_compile() {
316 jit_compile_quotation(ctx->pop(), true);
319 cell factor_vm::lazy_jit_compile_entry_point() {
320 return untag<word>(special_objects[LAZY_JIT_COMPILE_WORD])->entry_point;
323 // push a new quotation on the stack
325 void factor_vm::primitive_array_to_quotation() {
326 quotation* quot = allot<quotation>(sizeof(quotation));
328 quot->array = ctx->peek();
329 quot->cached_effect = false_object;
330 quot->cache_counter = false_object;
331 quot->entry_point = lazy_jit_compile_entry_point();
333 ctx->replace(tag<quotation>(quot));
336 // Allocates memory (from_unsigned_cell)
337 void factor_vm::primitive_quotation_code() {
338 data_root<quotation> quot(ctx->pop(), this);
340 ctx->push(from_unsigned_cell(quot->entry_point));
341 ctx->push(from_unsigned_cell((cell)quot->code() + quot->code()->size()));
345 fixnum factor_vm::quot_code_offset_to_scan(cell quot_, cell offset) {
346 data_root<quotation> quot(quot_, this);
347 data_root<array> array(quot->array, this);
349 quotation_jit compiler(quot.value(), false, false, this);
350 compiler.init_quotation(quot.value());
351 compiler.compute_position(offset);
352 compiler.iterate_quotation();
354 return compiler.get_position();
358 cell factor_vm::lazy_jit_compile(cell quot_) {
359 data_root<quotation> quot(quot_, this);
361 FACTOR_ASSERT(!quotation_compiled_p(quot.untagged()));
363 code_block* compiled =
364 jit_compile_quotation(quot.value(), quot.value(), true);
365 quot.untagged()->entry_point = compiled->entry_point();
371 VM_C_API cell lazy_jit_compile(cell quot, factor_vm* parent) {
372 return parent->lazy_jit_compile(quot);
375 bool factor_vm::quotation_compiled_p(quotation* quot) {
376 return quot->entry_point != 0 &&
377 quot->entry_point != lazy_jit_compile_entry_point();
380 void factor_vm::primitive_quotation_compiled_p() {
381 quotation* quot = untag_check<quotation>(ctx->pop());
382 ctx->push(tag_boolean(quotation_compiled_p(quot)));