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#include <assert.h>
#include <string.h>
#include <stdlib.h>
#include "opcode.h"
#include "compile.h"
#include "locfile.h"
struct inst {
struct inst* next;
struct inst* prev;
opcode op;
union {
uint16_t intval;
struct inst* target;
jv constant;
struct cfunction* cfunc;
} imm;
location source;
// Binding
// An instruction requiring binding (for parameters/variables)
// is in one of three states:
// bound_by = NULL - Unbound free variable
// bound_by = self - This instruction binds a variable
// bound_by = other - Uses variable bound by other instruction
// The immediate field is generally not meaningful until instructions
// are bound, and even then only for instructions which bind.
struct inst* bound_by;
char* symbol;
block subfn;
// This instruction is compiled as part of which function?
// (only used during block_compile)
struct bytecode* compiled;
int bytecode_pos; // position just after this insn
};
static inst* inst_new(opcode op) {
inst* i = malloc(sizeof(inst));
i->next = i->prev = 0;
i->op = op;
i->bytecode_pos = -1;
i->bound_by = 0;
i->symbol = 0;
i->subfn = gen_noop();
i->source = UNKNOWN_LOCATION;
return i;
}
static void inst_free(struct inst* i) {
free(i->symbol);
if (opcode_describe(i->op)->flags & OP_HAS_BLOCK) {
block_free(i->subfn);
}
if (opcode_describe(i->op)->flags & OP_HAS_CONSTANT) {
jv_free(i->imm.constant);
}
free(i);
}
static block inst_block(inst* i) {
block b = {i,i};
return b;
}
static int block_is_single(block b) {
return b.first && b.first == b.last;
}
static inst* block_take(block* b) {
if (b->first == 0) return 0;
inst* i = b->first;
if (i->next) {
i->next->prev = 0;
b->first = i->next;
i->next = 0;
} else {
b->first = 0;
b->last = 0;
}
return i;
}
block gen_location(location loc, block b) {
for (inst* i = b.first; i; i = i->next) {
if (i->source.start == UNKNOWN_LOCATION.start &&
i->source.end == UNKNOWN_LOCATION.end) {
i->source = loc;
}
}
return b;
}
block gen_noop() {
block b = {0,0};
return b;
}
block gen_op_simple(opcode op) {
assert(opcode_describe(op)->length == 1);
return inst_block(inst_new(op));
}
block gen_op_const(opcode op, jv constant) {
assert(opcode_describe(op)->flags & OP_HAS_CONSTANT);
inst* i = inst_new(op);
i->imm.constant = constant;
return inst_block(i);
}
block gen_op_target(opcode op, block target) {
assert(opcode_describe(op)->flags & OP_HAS_BRANCH);
assert(target.last);
inst* i = inst_new(op);
i->imm.target = target.last;
return inst_block(i);
}
block gen_op_targetlater(opcode op) {
assert(opcode_describe(op)->flags & OP_HAS_BRANCH);
inst* i = inst_new(op);
i->imm.target = 0;
return inst_block(i);
}
void inst_set_target(block b, block target) {
assert(block_is_single(b));
assert(opcode_describe(b.first->op)->flags & OP_HAS_BRANCH);
assert(target.last);
b.first->imm.target = target.last;
}
block gen_op_var_unbound(opcode op, const char* name) {
assert(opcode_describe(op)->flags & OP_HAS_VARIABLE);
inst* i = inst_new(op);
i->symbol = strdup(name);
return inst_block(i);
}
block gen_op_var_bound(opcode op, block binder) {
assert(block_is_single(binder));
block b = gen_op_var_unbound(op, binder.first->symbol);
b.first->bound_by = binder.first;
return b;
}
block gen_op_symbol(opcode op, const char* sym) {
assert(opcode_describe(op)->flags & OP_HAS_SYMBOL);
inst* i = inst_new(op);
i->symbol = strdup(sym);
return inst_block(i);
}
block gen_op_block_defn(opcode op, const char* name, block block) {
assert(opcode_describe(op)->flags & OP_IS_CALL_PSEUDO);
assert(opcode_describe(op)->flags & OP_HAS_BLOCK);
inst* i = inst_new(op);
i->subfn = block;
i->symbol = strdup(name);
return inst_block(i);
}
static void block_bind_subblock(block binder, block body, int bindflags);
block gen_op_block_defn_rec(opcode op, const char* name, block blk) {
block b = gen_op_block_defn(op, name, blk);
block_bind_subblock(b, b, OP_IS_CALL_PSEUDO | OP_HAS_BINDING);
return b;
}
block gen_op_block_unbound(opcode op, const char* name) {
assert(opcode_describe(op)->flags & OP_IS_CALL_PSEUDO);
inst* i = inst_new(op);
i->symbol = strdup(name);
return inst_block(i);
}
block gen_op_block_bound(opcode op, block binder) {
assert(block_is_single(binder));
block b = gen_op_block_unbound(op, binder.first->symbol);
b.first->bound_by = binder.first;
return b;
}
block gen_op_call(opcode op, block arglist) {
assert(opcode_describe(op)->flags & OP_HAS_VARIABLE_LENGTH_ARGLIST);
inst* i = inst_new(op);
block prelude = gen_noop();
block call = inst_block(i);
int nargs = 0;
inst* curr = 0;
while ((curr = block_take(&arglist))) {
assert(opcode_describe(curr->op)->flags & OP_IS_CALL_PSEUDO);
block bcurr = inst_block(curr);
switch (curr->op) {
default: assert(0 && "Unknown type of parameter"); break;
case CLOSURE_REF:
block_append(&call, bcurr);
break;
case CLOSURE_CREATE:
block_append(&prelude, bcurr);
block_append(&call, gen_op_block_bound(CLOSURE_REF, bcurr));
break;
}
nargs++;
}
assert(nargs < 100); //FIXME
i->imm.intval = nargs;
return block_join(prelude, call);
}
static void inst_join(inst* a, inst* b) {
assert(a && b);
assert(!a->next);
assert(!b->prev);
a->next = b;
b->prev = a;
}
void block_append(block* b, block b2) {
if (b2.first) {
if (b->last) {
inst_join(b->last, b2.first);
} else {
b->first = b2.first;
}
b->last = b2.last;
}
}
block block_join(block a, block b) {
block c = a;
block_append(&c, b);
return c;
}
int block_has_only_binders(block binders, int bindflags) {
bindflags |= OP_HAS_BINDING;
for (inst* curr = binders.first; curr; curr = curr->next) {
if ((opcode_describe(curr->op)->flags & bindflags) != bindflags) {
return 0;
}
}
return 1;
}
static void block_bind_subblock(block binder, block body, int bindflags) {
assert(block_is_single(binder));
assert((opcode_describe(binder.first->op)->flags & bindflags) == bindflags);
assert(binder.first->symbol);
assert(binder.first->bound_by == 0 || binder.first->bound_by == binder.first);
binder.first->bound_by = binder.first;
for (inst* i = body.first; i; i = i->next) {
int flags = opcode_describe(i->op)->flags;
if ((flags & bindflags) == bindflags &&
i->bound_by == 0 &&
!strcmp(i->symbol, binder.first->symbol)) {
// bind this instruction
i->bound_by = binder.first;
}
if (flags & OP_HAS_BLOCK) {
// binding recurses into closures
block_bind_subblock(binder, i->subfn, bindflags);
}
}
}
block block_bind(block binder, block body, int bindflags) {
assert(block_has_only_binders(binder, bindflags));
bindflags |= OP_HAS_BINDING;
for (inst* curr = binder.first; curr; curr = curr->next) {
block_bind_subblock(inst_block(curr), body, bindflags);
}
return block_join(binder, body);
}
block gen_subexp(block a) {
block c = gen_noop();
block_append(&c, gen_op_simple(DUP));
block_append(&c, a);
block_append(&c, gen_op_simple(SWAP));
return c;
}
block gen_both(block a, block b) {
block c = gen_noop();
block jump = gen_op_targetlater(JUMP);
block fork = gen_op_targetlater(FORK);
block_append(&c, fork);
block_append(&c, a);
block_append(&c, jump);
inst_set_target(fork, c);
block_append(&c, b);
inst_set_target(jump, c);
return c;
}
block gen_collect(block expr) {
block c = gen_noop();
block_append(&c, gen_op_simple(DUP));
block_append(&c, gen_op_const(LOADK, jv_array()));
block array_var = block_bind(gen_op_var_unbound(STOREV, "collect"),
gen_noop(), OP_HAS_VARIABLE);
block_append(&c, array_var);
block tail = {0};
block_append(&tail, gen_op_simple(DUP));
block_append(&tail, gen_op_var_bound(LOADV, array_var));
block_append(&tail, gen_op_simple(SWAP));
block_append(&tail, gen_op_simple(APPEND));
block_append(&tail, gen_op_var_bound(STOREV, array_var));
block_append(&tail, gen_op_simple(BACKTRACK));
block_append(&c, gen_op_target(FORK, tail));
block_append(&c, expr);
block_append(&c, tail);
block_append(&c, gen_op_var_bound(LOADV, array_var));
return c;
}
block gen_assign(block expr) {
block c = gen_noop();
block_append(&c, gen_op_simple(DUP));
block result_var = block_bind(gen_op_var_unbound(STOREV, "result"),
gen_noop(), OP_HAS_VARIABLE);
block_append(&c, result_var);
block loop = gen_noop();
block_append(&loop, gen_op_simple(DUP));
block_append(&loop, expr);
block_append(&loop, gen_op_var_bound(ASSIGN, result_var));
block_append(&loop, gen_op_simple(BACKTRACK));
block_append(&c, gen_op_target(FORK, loop));
block_append(&c, loop);
block_append(&c, gen_op_var_bound(LOADV, result_var));
return c;
}
block gen_definedor(block a, block b) {
// var found := false
block c = gen_op_simple(DUP);
block_append(&c, gen_op_const(LOADK, jv_false()));
block found_var = block_bind(gen_op_var_unbound(STOREV, "found"),
gen_noop(), OP_HAS_VARIABLE);
block_append(&c, found_var);
// if found, backtrack. Otherwise execute b
block tail = gen_op_simple(DUP);
block_append(&tail, gen_op_var_bound(LOADV, found_var));
block backtrack = gen_op_simple(BACKTRACK);
block_append(&tail, gen_op_target(JUMP_F, backtrack));
block_append(&tail, backtrack);
block_append(&tail, gen_op_simple(POP));
block_append(&tail, b);
// try again
block if_notfound = gen_op_simple(BACKTRACK);
// found := true, produce result
block if_found = gen_op_simple(DUP);
block_append(&if_found, gen_op_const(LOADK, jv_true()));
block_append(&if_found, gen_op_var_bound(STOREV, found_var));
block_append(&if_found, gen_op_target(JUMP, tail));
block_append(&c, gen_op_target(FORK, if_notfound));
block_append(&c, a);
block_append(&c, gen_op_target(JUMP_F, if_found));
block_append(&c, if_found);
block_append(&c, if_notfound);
block_append(&c, tail);
return c;
}
block gen_condbranch(block iftrue, block iffalse) {
block b = gen_noop();
block_append(&iftrue, gen_op_target(JUMP, iffalse));
block_append(&b, gen_op_target(JUMP_F, iftrue));
block_append(&b, iftrue);
block_append(&b, iffalse);
return b;
}
block gen_and(block a, block b) {
// a and b = if a then (if b then true else false) else false
block code = gen_op_simple(DUP);
block_append(&code, a);
block if_a_true = gen_op_simple(POP);
block_append(&if_a_true, b);
block_append(&if_a_true, gen_condbranch(gen_op_const(LOADK, jv_true()),
gen_op_const(LOADK, jv_false())));
block_append(&code, gen_condbranch(if_a_true,
block_join(gen_op_simple(POP), gen_op_const(LOADK, jv_false()))));
return code;
}
block gen_or(block a, block b) {
// a or b = if a then true else (if b then true else false)
block code = gen_op_simple(DUP);
block_append(&code, a);
block if_a_false = gen_op_simple(POP);
block_append(&if_a_false, b);
block_append(&if_a_false, gen_condbranch(gen_op_const(LOADK, jv_true()),
gen_op_const(LOADK, jv_false())));
block_append(&code, gen_condbranch(block_join(gen_op_simple(POP), gen_op_const(LOADK, jv_true())),
if_a_false));
return code;
}
block gen_cond(block cond, block iftrue, block iffalse) {
block b = gen_op_simple(DUP);
block_append(&b, cond);
block_append(&b, gen_condbranch(block_join(gen_op_simple(POP), iftrue),
block_join(gen_op_simple(POP), iffalse)));
return b;
}
block gen_cbinding(struct symbol_table* t, block code) {
for (int cfunc=0; cfunc<t->ncfunctions; cfunc++) {
inst* i = inst_new(CLOSURE_CREATE_C);
i->imm.cfunc = &t->cfunctions[cfunc];
i->symbol = strdup(i->imm.cfunc->name);
code = block_bind(inst_block(i), code, OP_IS_CALL_PSEUDO);
}
return code;
}
static uint16_t nesting_level(struct bytecode* bc, inst* target) {
uint16_t level = 0;
assert(bc && target->compiled);
while (bc && target->compiled != bc) {
level++;
bc = bc->parent;
}
assert(bc && bc == target->compiled);
return level;
}
static int count_cfunctions(block b) {
int n = 0;
for (inst* i = b.first; i; i = i->next) {
if (i->op == CLOSURE_CREATE_C) n++;
if (opcode_describe(i->op)->flags & OP_HAS_BLOCK)
n += count_cfunctions(i->subfn);
}
return n;
}
static int compile(struct locfile* locations, struct bytecode* bc, block b) {
int errors = 0;
int pos = 0;
int var_frame_idx = 0;
bc->nsubfunctions = 0;
bc->nclosures = 0;
for (inst* curr = b.first; curr; curr = curr->next) {
if (!curr->next) assert(curr == b.last);
pos += opcode_length(curr->op);
curr->bytecode_pos = pos;
curr->compiled = bc;
int opflags = opcode_describe(curr->op)->flags;
if (opflags & OP_HAS_BINDING) {
if (!curr->bound_by) {
locfile_locate(locations, curr->source, "error: %s is not defined", curr->symbol);
errors++;
}
}
if ((opflags & OP_HAS_VARIABLE) &&
curr->bound_by == curr) {
curr->imm.intval = var_frame_idx++;
}
if (opflags & OP_HAS_BLOCK) {
assert(curr->bound_by == curr);
curr->imm.intval = bc->nsubfunctions++;
}
if (curr->op == CLOSURE_PARAM) {
assert(curr->bound_by == curr);
curr->imm.intval = bc->nclosures++;
}
if (curr->op == CLOSURE_CREATE_C) {
assert(curr->bound_by == curr);
int idx = bc->globals->ncfunctions++;
bc->globals->cfunctions[idx] = *curr->imm.cfunc;
curr->imm.intval = idx;
}
}
if (bc->nsubfunctions) {
bc->subfunctions = malloc(sizeof(struct bytecode*) * bc->nsubfunctions);
for (inst* curr = b.first; curr; curr = curr->next) {
if (!(opcode_describe(curr->op)->flags & OP_HAS_BLOCK))
continue;
struct bytecode* subfn = malloc(sizeof(struct bytecode));
bc->subfunctions[curr->imm.intval] = subfn;
subfn->globals = bc->globals;
subfn->parent = bc;
errors += compile(locations, subfn, curr->subfn);
}
} else {
bc->subfunctions = 0;
}
bc->codelen = pos;
uint16_t* code = malloc(sizeof(uint16_t) * bc->codelen);
bc->code = code;
pos = 0;
jv constant_pool = jv_array();
int maxvar = -1;
if (!errors) for (inst* curr = b.first; curr; curr = curr->next) {
const struct opcode_description* op = opcode_describe(curr->op);
if (op->length == 0)
continue;
uint16_t* opcode_rewrite = &code[pos];
code[pos++] = curr->op;
int opflags = op->flags;
assert(!(op->flags & OP_IS_CALL_PSEUDO));
if (opflags & OP_HAS_VARIABLE_LENGTH_ARGLIST) {
int nargs = curr->imm.intval;
assert(nargs > 0);
code[pos++] = (uint16_t)nargs;
int desired_params = 0;
for (int i=0; i<nargs; i++) {
curr = curr->next;
assert(curr && opcode_describe(curr->op)->flags & OP_IS_CALL_PSEUDO);
code[pos++] = nesting_level(bc, curr->bound_by);
switch (curr->bound_by->op) {
default: assert(0 && "Unknown type of argument");
case CLOSURE_CREATE:
code[pos++] = curr->bound_by->imm.intval | ARG_NEWCLOSURE;
if (i == 0) {
inst* i = curr->bound_by;
desired_params = i->compiled->subfunctions[i->imm.intval]->nclosures;
}
break;
case CLOSURE_PARAM:
code[pos++] = curr->bound_by->imm.intval;
if (i == 0) desired_params = 0;
break;
case CLOSURE_CREATE_C:
code[pos++] = curr->bound_by->imm.intval;
*opcode_rewrite = bc->globals->cfunctions[curr->bound_by->imm.intval].callop;
if (i == 0) desired_params = 0;
break;
}
}
assert(nargs - 1 == desired_params);
} else if (opflags & OP_HAS_CONSTANT) {
code[pos++] = jv_array_length(jv_copy(constant_pool));
constant_pool = jv_array_append(constant_pool, jv_copy(curr->imm.constant));
} else if (opflags & OP_HAS_VARIABLE) {
code[pos++] = nesting_level(bc, curr->bound_by);
uint16_t var = (uint16_t)curr->bound_by->imm.intval;
code[pos++] = var;
if (var > maxvar) maxvar = var;
} else if (opflags & OP_HAS_BRANCH) {
assert(curr->imm.target->bytecode_pos != -1);
assert(curr->imm.target->bytecode_pos > pos); // only forward branches
code[pos] = curr->imm.target->bytecode_pos - (pos + 1);
pos++;
} else if (opflags & OP_HAS_CFUNC) {
assert(curr->symbol);
int found = 0;
for (int i=0; i<bc->globals->ncfunctions; i++) {
if (!strcmp(curr->symbol, bc->globals->cfunctions[i].name)) {
code[pos++] = i;
found = 1;
break;
}
}
assert(found);
} else if (op->length > 1) {
assert(0 && "codegen not implemented for this operation");
}
}
bc->constants = constant_pool;
bc->nlocals = maxvar + 2; // FIXME: frames of size zero?
return errors;
}
int block_compile(block b, struct locfile* locations, struct bytecode** out) {
struct bytecode* bc = malloc(sizeof(struct bytecode));
bc->parent = 0;
bc->globals = malloc(sizeof(struct symbol_table));
int ncfunc = count_cfunctions(b);
bc->globals->ncfunctions = 0;
bc->globals->cfunctions = malloc(sizeof(struct cfunction) * ncfunc);
int nerrors = compile(locations, bc, b);
assert(bc->globals->ncfunctions == ncfunc);
if (nerrors > 0) {
bytecode_free(bc);
*out = 0;
} else {
*out = bc;
}
return nerrors;
}
void block_free(block b) {
struct inst* next;
for (struct inst* curr = b.first; curr; curr = next) {
next = curr->next;
inst_free(curr);
}
}
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