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#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "to_assembly.h"
static bool is_function_label(const char *lbl) {
return memcmp(lbl, "__", 2) != 0;
}
static bool needs_0_eq_1(const struct irins *ins) {
return ins->type == INS_ADD || ins->type == INS_SUB || ins->type == INS_MUL ||
ins->type == INS_DIV || ins->type == INS_MOD || ins->type == INS_NEG ||
ins->type == INS_NOT;
}
static void fix_function(struct ir *ir, int startidx, struct allocation *ral) {
int spillspace = 0;
int of_cap = 32;
int *offsets = malloc(of_cap * sizeof(int));
memset(offsets, 0xff, of_cap * sizeof(int));
if (ir->inss[startidx]->type == INS_LBL && is_function_label(ir->inss[startidx]->name)) {
startidx++;
}
for (int idx = startidx; idx < ir->len; idx++) {
struct irins *ins = ir->inss[idx];
if (ins->type == INS_LBL && is_function_label(ins->name)) break;
if (ins->type == INS_CALLV) {
ins->type = INS_CALL;
ir_insert_before(ir, idx + 1, irins_make_01(INS_MOV, ins->r0, ref_reg(REG_A)));
idx--;
continue;
}
if (ins->type == INS_RETV) {
ir_insert_before(ir, idx, irins_make_01(INS_MOV, ref_reg(REG_A), ins->r1));
ins->type = INS_RET;
idx--;
continue;
}
// Apply the register allocation
bool haveref[3];
irins_which_refs(ins, haveref);
for (int ri = 0; ri < 3; ri++) {
struct ref *ref = &ins->three_refs[ri];
if (haveref[ri] && ref->type == REF_REG && ref->reg >= 0) {
if (ral->allocs[ref->reg].spill) {
int old_cap = of_cap;
while (ref->reg >= of_cap) {
of_cap *= 2;
offsets = realloc(offsets, of_cap * sizeof(int));
}
memset(offsets + old_cap * sizeof(int), 0xff, (of_cap - old_cap) * sizeof(int));
if (offsets[ref->reg] == -1) offsets[ref->reg] = ++spillspace;
*ref = ref_mem(REG_BP, -offsets[ref->reg], REFREL_ZERO);
} else {
ref->reg = ral->allocs[ref->reg].reg;
}
}
}
if (ins->type == INS_MUL) {
if (!ref_equal(ins->r1, ref_reg(REG_A))) {
ir_insert_before(ir, idx, irins_make_01(INS_MOV, ref_reg(REG_A), ins->r1));
ins->r1 = ref_reg(REG_A);
idx++;
}
if (!ref_equal(ins->r0, ref_reg(REG_A))) {
ir_insert_before(ir, idx + 1, irins_make_01(INS_MOV, ins->r0, ref_reg(REG_A)));
ins->r0 = ref_reg(REG_A);
}
} else if (needs_0_eq_1(ins) && !ref_equal(ins->r0, ins->r1)) {
ir_insert_before(ir, idx, irins_make_01(INS_MOV, ins->r0, ins->r1));
ins->r1 = ins->r0;
}
}
free(offsets);
// TODO: Really, nothing should be relative to BP, instead everything should use SP. That
// would completely eliminate this BP dance anyway.
// if (spillspace == 0) return;
ir_insert_before(ir, startidx + 0, irins_make_1(INS_PUSH, ref_reg(REG_BP)));
ir_insert_before(ir, startidx + 1, irins_make_01(INS_MOV, ref_reg(REG_BP), ref_reg(REG_SP)));
if (spillspace != 0) {
ir_insert_before(ir, startidx + 2,
irins_make_012(INS_SUB, ref_reg(REG_SP), ref_reg(REG_SP), ref_imm(spillspace)));
}
for (int idx = startidx + 1; idx < ir->len; idx++) {
struct irins *ins = ir->inss[idx];
if (ins->type == INS_LBL && is_function_label(ins->name)) break;
if (ins->type == INS_RET || ins->type == INS_BRK) {
ir_insert_before(ir, idx++, irins_make_01(INS_MOV, ref_reg(REG_SP), ref_reg(REG_BP)));
ir_insert_before(ir, idx++, irins_make_0(INS_POP, ref_reg(REG_BP)));
continue;
}
}
}
void to_assembly(struct ir *ir, struct allocation *ral) {
if (ir->len > 0 && (ir->inss[0]->type != INS_LBL || !is_function_label(ir->inss[0]->name))) {
fix_function(ir, 0, ral);
}
for (int idx = 0; idx < ir->len; idx++) {
if (ir->inss[idx]->type == INS_LBL && is_function_label(ir->inss[idx]->name)) {
fix_function(ir, idx, ral);
}
}
for (int idx = 0; idx < ir->len; idx++) {
struct irins *ins = ir->inss[idx];
bool haveref[3];
irins_which_refs(ins, haveref);
for (int ri = 0; ri < 3; ri++) {
struct ref *ref = &ins->three_refs[ri];
if (haveref[ri] && ref->type == REF_MEM) {
switch (ref->rel) {
case REFREL_ZERO: break;
case REFREL_DATA: ref->offset += 0x0200; break;
case REFREL_HEAP: ref->offset += 0x5000; fprintf(stderr, "WARNING: Using hard-coded heap start address\n"); break;
default: assert(false);
}
ref->rel = REFREL_ZERO;
}
}
}
}
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