//
//  gravity_ircode.c
//  gravity
//
//  Created by Marco Bambini on 06/11/14.
//  Copyright (c) 2014 CreoLabs. All rights reserved.
//

#include "gravity_ircode.h"
#include "gravity_value.h"
#include "gravity_debug.h"

typedef marray_t(inst_t *)		code_r;
typedef marray_t(bool *)		context_r;

struct ircode_t {
	code_r		*list;						// array of ircode instructions
	
	uint32_r	label_true;					// labels used in loops
	uint32_r	label_false;
	uint32_t	label_counter;
	
	uint32_t	maxtemp;					// maximum number of temp registers used in this ircode
	uint32_t	ntemps;						// current number of temp registers in use
	uint16_t	nlocals;					// number of local registers (params + local variables)
	bool		error;						// error flag set when no more registers are availables
	
	bool		state[MAX_REGISTERS];		// registers mask
	bool		skipclear[MAX_REGISTERS];	// registers protection for temps used in for loop
	uint32_r	registers;					// registers stack
	context_r	context;					// context array
};

ircode_t *ircode_create (uint16_t nlocals) {
	ircode_t *code = (ircode_t *)mem_alloc(sizeof(ircode_t));
	code->label_counter = 0;
	code->nlocals = nlocals;
	code->ntemps = 0;
	code->maxtemp = 0;
	code->error = false;
	
	code->list = mem_alloc(sizeof(code_r));
	marray_init(*code->list);
	marray_init(code->label_true);
	marray_init(code->label_false);
	marray_init(code->registers);
	marray_init(code->context);
	
	// init state array (register 0 is reserved)
	bzero(code->state, MAX_REGISTERS * sizeof(bool));
	code->state[0] = true;
	for (uint32_t i=0; i<nlocals; ++i) {
		code->state[i] = true;
	}
	return code;
}

void ircode_free (ircode_t *code) {
	uint32_t count = ircode_count(code);
	for (uint32_t i=0; i<count; ++i) {
		inst_t *inst = marray_get(*code->list, i);
		mem_free(inst);
	}
	
	marray_destroy(*code->list);
	marray_destroy(code->registers);
	marray_destroy(code->label_true);
	marray_destroy(code->label_false);
	mem_free(code->list);
	mem_free(code);
}

uint32_t ircode_ntemps (ircode_t *code) {
	return code->ntemps;
}

uint32_t ircode_count (ircode_t *code) {
	return (uint32_t)marray_size(*code->list);
}

inst_t *ircode_get (ircode_t *code, uint32_t index) {
	uint32_t n = (uint32_t)marray_size(*code->list);
	if (index == IRCODE_LATEST) index = n-1;
	return (index >= n) ? NULL : marray_get(*code->list, index);
}

bool ircode_iserror (ircode_t *code) {
	return code->error;
}
// MARK: -

static inst_t *inst_new (opcode_t op, uint32_t p1, uint32_t p2, uint32_t p3, optag_t tag, int64_t n, double d) {
	
	// debug code
	#if GRAVITY_OPCODE_DEBUG
	if (tag == LABEL_TAG) {
		DEBUG_OPCODE("LABEL %d", p1);
	} else {
		const char *op_name = opcode_name(op);
		
		if (op == LOADI) {
			if (tag == DOUBLE_TAG)
				printf("%s %d %.2f\n", op_name, p1, d);
			else
				printf("%s %d %lld\n", op_name, p1, n);
		} else {
			int nop = opcode_numop(op);
			if (nop == 0) {
				DEBUG_OPCODE("%s", op_name);
			} else if (nop == 1) {
				DEBUG_OPCODE("%s %d", op_name, p1);
			} else if (nop == 2) {
				DEBUG_OPCODE("%s %d %d", op_name, p1, p2);
			} else if (nop == 3) {
				DEBUG_OPCODE("%s %d %d %d", opcode_name(op), p1, p2, p3);
			}
		}
	}
	#endif
	
	inst_t *inst = (inst_t *)mem_alloc(sizeof(inst_t));
	inst->op = op;
	inst->tag = tag;
	inst->p1 = p1;
	inst->p2 = p2;
	inst->p3 = p3;
	
	if (tag == DOUBLE_TAG) inst->d = d;
	else if (tag == INT_TAG) inst->n = n;
	
	assert(inst);
	return inst;
}

void inst_setskip (inst_t *inst) {
	inst->tag = SKIP_TAG;
}

void ircode_patch_init (ircode_t *code, uint16_t index) {
	// prepend call instructions to code
	// LOADK temp index
	// LOAD  temp 0 temp
	// MOVE  temp+1 0
	// CALL  temp temp 1
	
	// load constant
	uint32_t dest = ircode_register_push_temp(code);
	inst_t *inst1 = inst_new(LOADK, dest, index, 0, NO_TAG, 0, 0.0);
	
	// load from lookup
	inst_t *inst2 = inst_new(LOAD, dest, 0, dest, NO_TAG, 0, 0.0);
	
	// prepare parameter
	uint32_t dest2 = ircode_register_push_temp(code);
	inst_t *inst3 = inst_new(MOVE, dest2, 0, 0, NO_TAG, 0, 0.0);
	ircode_register_pop(code);
	
	// execute call
	inst_t *inst4 = inst_new(CALL, dest, dest, 1, NO_TAG, 0, 0.0);
	
	// pop temps used
	ircode_register_pop(code);
	
	// create new instruction list
	code_r		*list = mem_alloc(sizeof(code_r));
	marray_init(*list);
	
	// add newly create instructions
	marray_push(inst_t*, *list, inst1);
	marray_push(inst_t*, *list, inst2);
	marray_push(inst_t*, *list, inst3);
	marray_push(inst_t*, *list, inst4);
	
	// then copy original instructions
	code_r *orig_list = code->list;
	uint32_t count = ircode_count(code);
	for (uint32_t i=0; i<count; ++i) {
		inst_t *inst = marray_get(*orig_list, i);
		marray_push(inst_t*, *list, inst);
	}
	
	// free dest list
	marray_destroy(*orig_list);
	mem_free(code->list);
	
	// replace dest list with the newly created list
	code->list = list;
}

uint8_t opcode_numop (opcode_t op) {
	switch (op) {
		case HALT: return 0;
		case NOP: return 0;
		case RET0: return 0;
		case RET: return 1;
		case CALL: return 3;
		case SETLIST: return 3;
		case LOADK: return 2;
		case LOADG: return 2;
		case LOADI: return 2;
		case LOADAT: return 3;
		case LOADS: return 3;
		case LOAD: return 3;
		case LOADU: return 2;
		case MOVE: return 2;
		case STOREG: return 2;
		case STOREAT: return 3;
		case STORE: return 3;
		case STOREU: return 2;
		case JUMP: return 1;
		case JUMPF: return 2;
		case SWITCH: return 1;
		case ADD: return 3;
		case SUB: return 3;
		case DIV: return 3;
		case MUL: return 3;
		case REM: return 3;
		case AND: return 3;
		case OR: return 3;
		case LT: return 3;
		case GT: return 3;
		case EQ: return 3;
		case ISA: return 3;
		case MATCH: return 3;
		case EQQ: return 3;
		case LEQ: return 3;
		case GEQ: return 3;
		case NEQ: return 3;
		case NEQQ: return 3;
		case NEG: return 2;
		case NOT: return 2;
		case LSHIFT: return 3;
		case RSHIFT: return 3;
		case BAND: return 3;
		case BOR: return 3;
		case BXOR: return 3;
		case BNOT: return 2;
		case MAPNEW: return 2;
		case LISTNEW: return 2;
		case RANGENEW: return 3;
		case CLOSURE: return 2;
		case CLOSE: return 1;
		case RESERVED1:
		case RESERVED2:
		case RESERVED3:
		case RESERVED4:
		case RESERVED5:
		case RESERVED6: return 0;
	}
	
	assert(0);
	return 0;
}

void ircode_dump  (void *_code) {
	ircode_t	*code = (ircode_t *)_code;
	code_r		*list = code->list;
	uint32_t	count = ircode_count(code);
	
	if (count == 0) {
		printf("NONE\n");
		return;
	}
	
	for (uint32_t i=0, line=0; i<count; ++i) {
		inst_t *inst = marray_get(*list, i);
		opcode_t	op = inst->op;
		int32_t		p1 = inst->p1;
		int32_t		p2 = inst->p2;
		int32_t		p3 = inst->p3;
		if (inst->tag == SKIP_TAG) continue;
		if (inst->tag == PRAGMA_OPTIMIZATION) continue;
		if (inst->tag == LABEL_TAG) {printf("LABEL %d:\n", p1); continue;}
		
		uint8_t n = opcode_numop(op);
		if ((op == SETLIST) && (p2 == 0)) n = 2;
		
		switch (n) {
			case 0: {
				printf("%05d\t%s\n", line, opcode_name(op));
			}
			
			case 1: {
				printf("%05d\t%s %d\n", line, opcode_name(op), p1);
			} break;
				
			case 2: {
				if (op == LOADI) {
					if (inst->tag == DOUBLE_TAG) printf("%05d\t%s %d %.2f\n", line, opcode_name(op), p1, inst->d);
					else printf("%05d\t%s %d %d\n", line, opcode_name(op), p1, (int32_t)inst->n);
				} else if (op == LOADK) {
					if (p2 < CPOOL_INDEX_MAX) printf("%05d\t%s %d %d\n", line, opcode_name(op), p1, p2);
					else printf("%05d\t%s %d %s\n", line, opcode_name(op), p1, opcode_constname(p2));
				} else {
					printf("%05d\t%s %d %d\n", line, opcode_name(op), p1, p2);
				}
			} break;
				
			case 3: {
				printf("%05d\t%s %d %d %d\n", line, opcode_name(op), p1, p2, p3);
			} break;
				
			default: assert(0);
		}
		++line;
	}
}

// MARK: -

uint32_t ircode_newlabel (ircode_t *code) {
	return ++code->label_counter;
}

void ircode_setlabel_true (ircode_t *code, uint32_t nlabel) {
	marray_push(uint32_t, code->label_true, nlabel);
}

void ircode_setlabel_false (ircode_t *code, uint32_t nlabel) {
	marray_push(uint32_t, code->label_false, nlabel);
}

void ircode_unsetlabel_true (ircode_t *code) {
	marray_pop(code->label_true);
}

void ircode_unsetlabel_false (ircode_t *code) {
	marray_pop(code->label_false);
}

uint32_t ircode_getlabel_true (ircode_t *code) {
	size_t n = marray_size(code->label_true);
	uint32_t v = marray_get(code->label_true, n-1);
	return v;
}

uint32_t ircode_getlabel_false (ircode_t *code) {
	size_t n = marray_size(code->label_false);
	uint32_t v = marray_get(code->label_false, n-1);
	return v;
}

void ircode_marklabel (ircode_t *code, uint32_t nlabel) {
	inst_t *inst = inst_new(0, nlabel, 0, 0, LABEL_TAG, 0, 0.0);
	marray_push(inst_t*, *code->list, inst);
}

// MARK: -

void ircode_set_index (uint32_t index, ircode_t *code, opcode_t op, uint32_t p1, uint32_t p2, uint32_t p3) {
	inst_t *inst = marray_get(*code->list, index);
	inst->op = op;
	inst->p1 = p1;
	inst->p2 = p2;
	inst->p3 = p3;
	inst->tag = NO_TAG;
}

void ircode_add (ircode_t *code, opcode_t op, uint32_t p1, uint32_t p2, uint32_t p3) {
	ircode_add_tag(code, op, p1, p2, p3, 0);
}

void ircode_add_tag (ircode_t *code, opcode_t op, uint32_t p1, uint32_t p2, uint32_t p3, optag_t tag) {
	inst_t *inst = inst_new(op, p1, p2, p3, tag, 0, 0.0);
	marray_push(inst_t*, *code->list, inst);
}

void ircode_add_double (ircode_t *code, double d) {
	uint32_t regnum = ircode_register_push_temp(code);
	inst_t *inst = inst_new(LOADI, regnum, 0, 0, DOUBLE_TAG, 0, d);
	marray_push(inst_t*, *code->list, inst);
}

void ircode_add_constant (ircode_t *code, uint32_t index) {
	uint32_t regnum = ircode_register_push_temp(code);
	inst_t *inst = inst_new(LOADK, regnum, index, 0, NO_TAG, 0, 0);
	marray_push(inst_t*, *code->list, inst);
}

void ircode_add_int (ircode_t *code, int64_t n) {
	uint32_t regnum = ircode_register_push_temp(code);
	inst_t *inst = inst_new(LOADI, regnum, 0, 0, INT_TAG, n, 0);
	marray_push(inst_t*, *code->list, inst);
}

void ircode_add_skip (ircode_t *code) {
	inst_t *inst = inst_new(0, 0, 0, 0, NO_TAG, 0, 0);
	inst_setskip(inst);
	marray_push(inst_t*, *code->list, inst);
}

// MARK: - Context based functions -

#if 0
static void dump_context(bool *context) {
	for (uint32_t i=0; i<MAX_REGISTERS; ++i) {
		printf("%d ", context[i]);
	}
	printf("\n");
}
#endif

void ircode_push_context (ircode_t *code) {
	bool *context = mem_alloc(sizeof(bool) * MAX_REGISTERS);
	marray_push(bool *, code->context, context);
}

void ircode_pop_context (ircode_t *code) {
	bool *context = marray_pop(code->context);
	// apply context mask
	for (uint32_t i=0; i<MAX_REGISTERS; ++i) {
		if (context[i]) code->state[i] = false;
	}
	mem_free(context);
}

uint32_t ircode_register_pop_context_protect (ircode_t *code, bool protect) {
	assert(marray_size(code->registers) != 0);
	uint32_t value = (uint32_t)marray_pop(code->registers);
	
	if (protect) code->state[value] = true;
	else if (value >= code->nlocals) code->state[value] = false;
	
	if (protect && value >= code->nlocals) {
		bool *context = marray_last(code->context);
		context[value] = true;
	}
	
	DEBUG_REGISTER("POP REGISTER %d", value);
	return value;
}

void ircode_register_protect_outside_context (ircode_t *code, uint32_t nreg) {
	if (nreg < code->nlocals) return;
	assert(code->state[nreg]);
	bool *context = marray_last(code->context);
	context[nreg] = false;
}

void ircode_register_protect_in_context (ircode_t *code, uint32_t nreg) {
	assert(code->state[nreg]);
	bool *context = marray_last(code->context);
	context[nreg] = true;
}

// MARK: -

static uint32_t ircode_register_new (ircode_t *code) {
	for (uint32_t i=0; i<MAX_REGISTERS; ++i) {
		if (code->state[i] == false) {
			code->state[i] = true;
			return i;
		}
	}
	// 0 means no registers available
	code->error = true;
	return 0;
}

uint32_t ircode_register_push (ircode_t *code, uint32_t nreg) {
	marray_push(uint32_t, code->registers, nreg);
	if (ircode_register_istemp(code, nreg)) ++code->ntemps;
	
	DEBUG_REGISTER("PUSH REGISTER %d", nreg);
	return nreg;
}

uint32_t ircode_register_push_temp (ircode_t *code) {
	uint32_t value = ircode_register_new(code);
	marray_push(uint32_t, code->registers, value);
	if (value > code->maxtemp) {code->maxtemp = value; ++code->ntemps;}
	
	DEBUG_REGISTER("PUSH REGISTER %d", value);
	return value;
}

uint32_t ircode_register_pop (ircode_t *code) {
	return ircode_register_pop_context_protect(code, false);
}

void ircode_register_clear (ircode_t *code, uint32_t nreg) {
	// cleanup busy mask only if it is a temp register
	if (nreg >= code->nlocals) code->state[nreg] = false;
}

uint32_t ircode_register_last (ircode_t *code) {
	assert(marray_size(code->registers) != 0);
	uint32_t value = (uint32_t)marray_last(code->registers);
	
	return value;
}

bool ircode_register_istemp (ircode_t *code, uint32_t nreg) {
	return (nreg >= (uint32_t)code->nlocals);
}

void ircode_register_dump (ircode_t *code) {
	uint32_t n = (uint32_t)marray_size(code->registers);
	if (n == 0) printf("EMPTY\n");
	for (uint32_t i=0; i<n; ++i) {
		uint32_t value = marray_get(code->registers, i);
		printf("[%d]\t%d\n", i, value);
	}
}

uint32_t ircode_register_count (ircode_t *code) {
	return (uint32_t)marray_size(code->registers);
}

// MARK: -

void ircode_register_set_skip_clear (ircode_t *code, uint32_t nreg) {
	code->skipclear[nreg] = true;
}

void ircode_register_unset_skip_clear (ircode_t *code, uint32_t nreg) {
	code->skipclear[nreg] = false;
}

void ircode_register_clear_temps (ircode_t *code) {
	// clear all temporary registers (if not protected)
	for (uint32_t i=code->nlocals; i<=code->maxtemp; ++i) {
		if (!code->skipclear[i]) code->state[i] = false;
	}
}