/*
 * Copyright (C) 2012 
 *     Wolfgang Bumiller
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include <stdlib.h>
#include <string.h>
#include "gmqcc.h"
#include "ir.h"

/***********************************************************************
 *IR Builder
 */

ir_builder* ir_builder_new(const char *modulename)
{
    ir_builder* self;

    self = (ir_builder*)mem_a(sizeof(*self));
    MEM_VECTOR_INIT(self, functions);
    MEM_VECTOR_INIT(self, globals);
    self->name = NULL;
    ir_builder_set_name(self, modulename);

    /* globals which always exist */

    /* for now we give it a vector size */
    ir_builder_create_global(self, "OFS_RETURN", qc_variant);

    return self;
}

MEM_VEC_FUNCTIONS(ir_builder, ir_value*, globals)
MEM_VEC_FUNCTIONS(ir_builder, ir_function*, functions)

void ir_builder_delete(ir_builder* self)
{
    size_t i;
    mem_d((void*)self->name);
    for (i = 0; i != self->functions_count; ++i) {
        ir_function_delete(self->functions[i]);
    }
    MEM_VECTOR_CLEAR(self, functions);
    for (i = 0; i != self->globals_count; ++i) {
        ir_value_delete(self->globals[i]);
    }
    MEM_VECTOR_CLEAR(self, globals);
    mem_d(self);
}

void ir_builder_set_name(ir_builder *self, const char *name)
{
    if (self->name)
        mem_d((void*)self->name);
    self->name = util_strdup(name);
}

ir_function* ir_builder_get_function(ir_builder *self, const char *name)
{
    size_t i;
    for (i = 0; i < self->functions_count; ++i) {
        if (!strcmp(name, self->functions[i]->name))
            return self->functions[i];
    }
    return NULL;
}

ir_function* ir_builder_create_function(ir_builder *self, const char *name)
{
    ir_function *fn = ir_builder_get_function(self, name);
    if (fn) {
        return NULL;
    }

    fn = ir_function_new(self);
    ir_function_set_name(fn, name);
    ir_builder_functions_add(self, fn);
    return fn;
}

ir_value* ir_builder_get_global(ir_builder *self, const char *name)
{
    size_t i;
    for (i = 0; i < self->globals_count; ++i) {
        if (!strcmp(self->globals[i]->name, name))
            return self->globals[i];
    }
    return NULL;
}

ir_value* ir_builder_create_global(ir_builder *self, const char *name, int vtype)
{
    ir_value *ve = ir_builder_get_global(self, name);
    if (ve) {
        return NULL;
    }

    ve = ir_value_var(name, store_global, vtype);
    ir_builder_globals_add(self, ve);
    return ve;
}

/***********************************************************************
 *IR Function
 */

void ir_function_naive_phi(ir_function*);
void ir_function_enumerate(ir_function*);
void ir_function_calculate_liferanges(ir_function*);

ir_function* ir_function_new(ir_builder* owner)
{
    ir_function *self;
    self = (ir_function*)mem_a(sizeof(*self));
    self->owner = owner;
    self->context.file = "<@no context>";
    self->context.line = 0;
    self->retype = qc_void;
    MEM_VECTOR_INIT(self, params);
    MEM_VECTOR_INIT(self, blocks);
    MEM_VECTOR_INIT(self, values);
    MEM_VECTOR_INIT(self, locals);
    ir_function_set_name(self, "<@unnamed>");

    self->run_id = 0;
    return self;
}
MEM_VEC_FUNCTIONS(ir_function, ir_value*, values)
MEM_VEC_FUNCTIONS(ir_function, ir_block*, blocks)
MEM_VEC_FUNCTIONS(ir_function, ir_value*, locals)

void ir_function_set_name(ir_function *self, const char *name)
{
    if (self->name)
        mem_d((void*)self->name);
    self->name = util_strdup(name);
}

void ir_function_delete(ir_function *self)
{
    size_t i;
    mem_d((void*)self->name);

    for (i = 0; i != self->blocks_count; ++i)
        ir_block_delete(self->blocks[i]);
    MEM_VECTOR_CLEAR(self, blocks);

    MEM_VECTOR_CLEAR(self, params);

    for (i = 0; i != self->values_count; ++i)
        ir_value_delete(self->values[i]);
    MEM_VECTOR_CLEAR(self, values);

    for (i = 0; i != self->locals_count; ++i)
        ir_value_delete(self->locals[i]);
    MEM_VECTOR_CLEAR(self, locals);

    mem_d(self);
}

void ir_function_collect_value(ir_function *self, ir_value *v)
{
    ir_function_values_add(self, v);
}

ir_block* ir_function_create_block(ir_function *self, const char *label)
{
    ir_block* bn = ir_block_new(self, label);
    memcpy(&bn->context, &self->context, sizeof(self->context));
    ir_function_blocks_add(self, bn);
    return bn;
}

void ir_function_finalize(ir_function *self)
{
    ir_function_naive_phi(self);
    ir_function_enumerate(self);
    ir_function_calculate_liferanges(self);
}

ir_value* ir_function_get_local(ir_function *self, const char *name)
{
    size_t i;
    for (i = 0; i < self->locals_count; ++i) {
        if (!strcmp(self->locals[i]->name, name))
            return self->locals[i];
    }
    return NULL;
}

ir_value* ir_function_create_local(ir_function *self, const char *name, int vtype)
{
    ir_value *ve = ir_function_get_local(self, name);
    if (ve) {
        return NULL;
    }

    ve = ir_value_var(name, store_local, vtype);
    ir_function_locals_add(self, ve);
    return ve;
}

/***********************************************************************
 *IR Block
 */

ir_block* ir_block_new(ir_function* owner, const char *name)
{
    ir_block *self;
    self = (ir_block*)mem_a(sizeof(*self));
    self->owner = owner;
    self->context.file = "<@no context>";
    self->context.line = 0;
    self->final = false;
    MEM_VECTOR_INIT(self, instr);
    MEM_VECTOR_INIT(self, entries);
    MEM_VECTOR_INIT(self, exits);
    self->label = NULL;
    ir_block_set_label(self, name);

    self->eid = 0;
    self->is_return = false;
    self->run_id = 0;
    MEM_VECTOR_INIT(self, living);
    return self;
}
MEM_VEC_FUNCTIONS(ir_block, ir_instr*, instr)
MEM_VEC_FUNCTIONS_ALL(ir_block, ir_block*, entries)
MEM_VEC_FUNCTIONS_ALL(ir_block, ir_block*, exits)
MEM_VEC_FUNCTIONS_ALL(ir_block, ir_value*, living)

void ir_block_delete(ir_block* self)
{
    size_t i;
    mem_d((void*)self->label);
    for (i = 0; i != self->instr_count; ++i)
        ir_instr_delete(self->instr[i]);
    MEM_VECTOR_CLEAR(self, instr);
    MEM_VECTOR_CLEAR(self, entries);
    MEM_VECTOR_CLEAR(self, exits);
    MEM_VECTOR_CLEAR(self, living);
    mem_d(self);
}

void ir_block_set_label(ir_block *self, const char *name)
{
    if (self->label)
        mem_d((void*)self->label);
    self->label = util_strdup(name);
}

/***********************************************************************
 *IR Instructions
 */

ir_instr* ir_instr_new(ir_block* owner, int op)
{
    ir_instr *self;
    self = (ir_instr*)mem_a(sizeof(*self));
    self->owner = owner;
    self->context.file = "<@no context>";
    self->context.line = 0;
    self->opcode = op;
    self->_ops[0] = NULL;
    self->_ops[1] = NULL;
    self->_ops[2] = NULL;
    self->bops[0] = NULL;
    self->bops[1] = NULL;
    MEM_VECTOR_INIT(self, phi);

    self->eid = 0;
    return self;
}
MEM_VEC_FUNCTIONS(ir_instr, ir_phi_entry_t, phi)

void ir_instr_delete(ir_instr *self)
{
    ir_instr_op(self, 0, NULL, false);
    ir_instr_op(self, 1, NULL, false);
    ir_instr_op(self, 2, NULL, false);
    MEM_VECTOR_CLEAR(self, phi);
    mem_d(self);
}

void ir_instr_op(ir_instr *self, int op, ir_value *v, bool writing)
{
    if (self->_ops[op]) {
        if (writing)
            ir_value_writes_add(self->_ops[op], self);
        else
            ir_value_reads_add(self->_ops[op], self);
    }
    if (v) {
        if (writing)
            ir_value_writes_add(v, self);
        else
            ir_value_reads_add(v, self);
    }
    self->_ops[op] = v;
}

/***********************************************************************
 *IR Value
 */

ir_value* ir_value_var(const char *name, int storetype, int vtype)
{
    ir_value *self;
    self = (ir_value*)mem_a(sizeof(*self));
    self->vtype = vtype;
    self->store = storetype;
    MEM_VECTOR_INIT(self, reads);
    MEM_VECTOR_INIT(self, writes);
    self->isconst = false;
    self->context.file = "<@no context>";
    self->context.line = 0;
    self->name = NULL;
    ir_value_set_name(self, name);

    MEM_VECTOR_INIT(self, life);
    return self;
}
MEM_VEC_FUNCTIONS(ir_value, ir_life_entry_t, life)
MEM_VEC_FUNCTIONS(ir_value, ir_instr*, reads)
MEM_VEC_FUNCTIONS(ir_value, ir_instr*, writes)

ir_value* ir_value_out(ir_function *owner, const char *name, int storetype, int vtype)
{
    ir_value *v = ir_value_var(name, storetype, vtype);
    ir_function_collect_value(owner, v);
    return v;
}

void ir_value_delete(ir_value* self)
{
    mem_d((void*)self->name);
    if (self->isconst)
    {
        if (self->vtype == qc_string)
            mem_d((void*)self->constval.vstring);
    }
    MEM_VECTOR_CLEAR(self, reads);
    MEM_VECTOR_CLEAR(self, writes);
    MEM_VECTOR_CLEAR(self, life);
    mem_d(self);
}

void ir_value_set_name(ir_value *self, const char *name)
{
    if (self->name)
        mem_d((void*)self->name);
    self->name = util_strdup(name);
}

bool ir_value_set_float(ir_value *self, float f)
{
    if (self->vtype != qc_float)
        return false;
    self->constval.vfloat = f;
    self->isconst = true;
    return true;
}

bool ir_value_set_vector(ir_value *self, vector_t v)
{
    if (self->vtype != qc_vector)
        return false;
    self->constval.vvec = v;
    self->isconst = true;
    return true;
}

bool ir_value_set_string(ir_value *self, const char *str)
{
    if (self->vtype != qc_string)
        return false;
    self->constval.vstring = util_strdup(str);
    self->isconst = true;
    return true;
}

bool ir_value_set_int(ir_value *self, int i)
{
    if (self->vtype != qc_int)
        return false;
    self->constval.vint = i;
    self->isconst = true;
    return true;
}

bool ir_value_lives(ir_value *self, size_t at)
{
    size_t i;
    for (i = 0; i < self->life_count; ++i)
    {
        ir_life_entry_t *life = &self->life[i];
        if (life->start <= at && at <= life->end)
            return true;
        if (life->start > at) /* since it's ordered */
            return false;
    }
    return false;
}

void ir_value_life_insert(ir_value *self, size_t idx, ir_life_entry_t e)
{
    size_t k;
    ir_value_life_add(self, e); /* naive... */
    for (k = self->life_count-1; k > idx; --k)
        self->life[k] = self->life[k-1];
    self->life[idx] = e;
}

bool ir_value_life_merge(ir_value *self, size_t s)
{
    size_t i;
    ir_life_entry_t *life = NULL;
    ir_life_entry_t *before = NULL;
    ir_life_entry_t new_entry;

    /* Find the first range >= s */
    for (i = 0; i < self->life_count; ++i)
    {
        before = life;
        life = &self->life[i];
        if (life->start > s)
            break;
    }
    /* nothing found? append */
    if (i == self->life_count) {
        if (life && life->end+1 == s)
        {
            /* previous life range can be merged in */
            life->end++;
            return true;
        }
        if (life && life->end >= s)
            return false;
        ir_life_entry_t e;
        e.start = e.end = s;
        ir_value_life_add(self, e);
        return true;
    }
    /* found */
    if (before)
    {
        if (before->end + 1 == s &&
            life->start - 1 == s)
        {
            /* merge */
            before->end = life->end;
            ir_value_life_remove(self, i);
            return true;
        }
        if (before->end + 1 == s)
        {
            /* extend before */
            before->end++;
            return true;
        }
        /* already contained */
        if (before->end >= s)
            return false;
    }
    /* extend */
    if (life->start - 1 == s)
    {
        life->start--;
        return true;
    }
    /* insert a new entry */
    new_entry.start = new_entry.end = s;
    ir_value_life_insert(self, i, new_entry);
    return true;
}

/***********************************************************************
 *IR main operations
 */

bool ir_block_create_store_op(ir_block *self, int op, ir_value *target, ir_value *what)
{
    if (target->store == store_value) {
        fprintf(stderr, "cannot store to an SSA value\n");
        return false;
    } else {
        ir_instr *in = ir_instr_new(self, op);
        ir_instr_op(in, 0, target, true);
        ir_instr_op(in, 1, what, false);
        ir_block_instr_add(self, in);
        return true;
    }
}

bool ir_block_create_store(ir_block *self, ir_value *target, ir_value *what)
{
    int op = 0;
    int vtype;
    if (target->vtype == qc_variant)
        vtype = what->vtype;
    else
        vtype = target->vtype;

    switch (vtype) {
        case qc_float:
#if 0
            if (what->vtype == qc_int)
                op = INSTR_CONV_ITOF;
            else
#endif
                op = INSTR_STORE_F;
            break;
        case qc_vector:
            op = INSTR_STORE_V;
            break;
        case qc_entity:
            op = INSTR_STORE_ENT;
            break;
        case qc_string:
            op = INSTR_STORE_S;
            break;
#if 0
        case qc_int:
            if (what->vtype == qc_int)
                op = INSTR_CONV_FTOI;
            else
                op = INSTR_STORE_I;
            break;
#endif
        case qc_pointer:
#if 0
            op = INSTR_STORE_I;
#else
            op = INSTR_STORE_ENT;
#endif
            break;
    }
    return ir_block_create_store_op(self, op, target, what);
}

void ir_block_create_return(ir_block *self, ir_value *v)
{
    ir_instr *in;
    if (self->final) {
        fprintf(stderr, "block already ended (%s)\n", self->label);
        return;
    }
    self->final = true;
    self->is_return = true;
    in = ir_instr_new(self, INSTR_RETURN);
    ir_instr_op(in, 0, v, false);
    ir_block_instr_add(self, in);
}

void ir_block_create_if(ir_block *self, ir_value *v,
                        ir_block *ontrue, ir_block *onfalse)
{
    ir_instr *in;
    if (self->final) {
        fprintf(stderr, "block already ended (%s)\n", self->label);
        return;
    }
    self->final = true;
    //in = ir_instr_new(self, (v->vtype == qc_string ? INSTR_IF_S : INSTR_IF_F));
    in = ir_instr_new(self, VINSTR_COND);
    ir_instr_op(in, 0, v, false);
    in->bops[0] = ontrue;
    in->bops[1] = onfalse;
    ir_block_instr_add(self, in);

    ir_block_exits_add(self, ontrue);
    ir_block_exits_add(self, onfalse);
    ir_block_entries_add(ontrue, self);
    ir_block_entries_add(onfalse, self);
}

void ir_block_create_jump(ir_block *self, ir_block *to)
{
    ir_instr *in;
    if (self->final) {
        fprintf(stderr, "block already ended (%s)\n", self->label);
        return;
    }
    self->final = true;
    in = ir_instr_new(self, VINSTR_JUMP);
    in->bops[0] = to;
    ir_block_instr_add(self, in);

    ir_block_exits_add(self, to);
    ir_block_entries_add(to, self);
}

void ir_block_create_goto(ir_block *self, ir_block *to)
{
    ir_instr *in;
    if (self->final) {
        fprintf(stderr, "block already ended (%s)\n", self->label);
        return;
    }
    self->final = true;
    in = ir_instr_new(self, INSTR_GOTO);
    in->bops[0] = to;
    ir_block_instr_add(self, in);

    ir_block_exits_add(self, to);
    ir_block_entries_add(to, self);
}

ir_instr* ir_block_create_phi(ir_block *self, const char *label, int ot)
{
    ir_value *out;
    ir_instr *in;
    in = ir_instr_new(self, VINSTR_PHI);
    out = ir_value_out(self->owner, label, store_local, ot);
    ir_instr_op(in, 0, out, true);
    ir_block_instr_add(self, in);
    return in;
}

ir_value* ir_phi_value(ir_instr *self)
{
    return self->_ops[0];
}

void ir_phi_add(ir_instr* self, ir_block *b, ir_value *v)
{
    ir_phi_entry_t pe;

    if (!ir_block_entries_find(self->owner, b, NULL)) {
        /* Must not be possible to cause this, otherwise the AST
         * is doing something wrong.
         */
        fprintf(stderr, "Invalid entry block for PHI\n");
        abort();
    }

    pe.value = v;
    pe.from = b;
    ir_value_reads_add(v, self);
    ir_instr_phi_add(self, pe);
}

/* binary op related code */

ir_value* ir_block_create_binop(ir_block *self,
                                const char *label, int opcode,
                                ir_value *left, ir_value *right)
{
    int ot = qc_void;
    switch (opcode) {
        case INSTR_ADD_F:
        case INSTR_SUB_F:
        case INSTR_DIV_F:
        case INSTR_MUL_F:
        case INSTR_MUL_V:
        case INSTR_AND:
        case INSTR_OR:
#if 0
        case INSTR_AND_I:
        case INSTR_AND_IF:
        case INSTR_AND_FI:
        case INSTR_OR_I:
        case INSTR_OR_IF:
        case INSTR_OR_FI:
#endif
        case INSTR_BITAND:
        case INSTR_BITOR:
#if 0
        case INSTR_SUB_S: /* -- offset of string as float */
        case INSTR_MUL_IF:
        case INSTR_MUL_FI:
        case INSTR_DIV_IF:
        case INSTR_DIV_FI:
        case INSTR_BITOR_IF:
        case INSTR_BITOR_FI:
        case INSTR_BITAND_FI:
        case INSTR_BITAND_IF:
        case INSTR_EQ_I:
        case INSTR_NE_I:
#endif
            ot = qc_float;
            break;
#if 0
        case INSTR_ADD_I:
        case INSTR_ADD_IF:
        case INSTR_ADD_FI:
        case INSTR_SUB_I:
        case INSTR_SUB_FI:
        case INSTR_SUB_IF:
        case INSTR_MUL_I:
        case INSTR_DIV_I:
        case INSTR_BITAND_I:
        case INSTR_BITOR_I:
        case INSTR_XOR_I:
        case INSTR_RSHIFT_I:
        case INSTR_LSHIFT_I:
            ot = qc_int;
            break;
#endif
        case INSTR_ADD_V:
        case INSTR_SUB_V:
        case INSTR_MUL_VF:
        case INSTR_MUL_FV:
#if 0
        case INSTR_DIV_VF:
        case INSTR_MUL_IV:
        case INSTR_MUL_VI:
#endif
            ot = qc_vector;
            break;
#if 0
        case INSTR_ADD_SF:
            ot = qc_pointer;
            break;
#endif
        default:
            // ranges:
            /* boolean operations result in floats */
            if (opcode >= INSTR_EQ_F && opcode <= INSTR_GT)
                ot = qc_float;
            else if (opcode >= INSTR_LE && opcode <= INSTR_GT)
                ot = qc_float;
#if 0
            else if (opcode >= INSTR_LE_I && opcode <= INSTR_EQ_FI)
                ot = qc_float;
#endif
            break;
    };
    if (ot == qc_void) {
        /* The AST or parser were supposed to check this! */
        abort();
        return NULL;
    }
    ir_value *out = ir_value_out(self->owner, label, store_local, ot);
    ir_instr *in = ir_instr_new(self, opcode);
    ir_instr_op(in, 0, out, true);
    ir_instr_op(in, 1, left, false);
    ir_instr_op(in, 2, right, false);
    ir_block_instr_add(self, in);
    return out;
}

ir_value* ir_block_create_add(ir_block *self,
                              const char *label,
                              ir_value *left, ir_value *right)
{
    int op = 0;
    int l = left->vtype;
    int r = right->vtype;
    if (l == r) {
        switch (l) {
            default:
                return NULL;
            case qc_float:
                op = INSTR_ADD_F;
                break;
#if 0
            case qc_int:
                op = INSTR_ADD_I;
                break;
#endif
            case qc_vector:
                op = INSTR_ADD_V;
                break;
        }
    } else {
#if 0
        if ( (l == qc_float && r == qc_int) )
            op = INSTR_ADD_FI;
        else if ( (l == qc_int && r == qc_float) )
            op = INSTR_ADD_IF;
        else
#endif
            return NULL;
    }
    return ir_block_create_binop(self, label, op, left, right);
}

ir_value* ir_block_create_sub(ir_block *self,
                              const char *label,
                              ir_value *left, ir_value *right)
{
    int op = 0;
    int l = left->vtype;
    int r = right->vtype;
    if (l == r) {

        switch (l) {
            default:
                return NULL;
            case qc_float:
                op = INSTR_SUB_F;
                break;
#if 0
            case qc_int:
                op = INSTR_SUB_I;
                break;
#endif
            case qc_vector:
                op = INSTR_SUB_V;
                break;
        }
    } else {
#if 0
        if ( (l == qc_float && r == qc_int) )
            op = INSTR_SUB_FI;
        else if ( (l == qc_int && r == qc_float) )
            op = INSTR_SUB_IF;
        else
#endif
            return NULL;
    }
    return ir_block_create_binop(self, label, op, left, right);
}

ir_value* ir_block_create_mul(ir_block *self,
                              const char *label,
                              ir_value *left, ir_value *right)
{
    int op = 0;
    int l = left->vtype;
    int r = right->vtype;
    if (l == r) {

        switch (l) {
            default:
                return NULL;
            case qc_float:
                op = INSTR_MUL_F;
                break;
#if 0
            case qc_int:
                op = INSTR_MUL_I;
                break;
#endif
            case qc_vector:
                op = INSTR_MUL_V;
                break;
        }
    } else {
        if ( (l == qc_vector && r == qc_float) )
            op = INSTR_MUL_VF;
        else if ( (l == qc_float && r == qc_vector) )
            op = INSTR_MUL_FV;
#if 0
        else if ( (l == qc_vector && r == qc_int) )
            op = INSTR_MUL_VI;
        else if ( (l == qc_int && r == qc_vector) )
            op = INSTR_MUL_IV;
        else if ( (l == qc_float && r == qc_int) )
            op = INSTR_MUL_FI;
        else if ( (l == qc_int && r == qc_float) )
            op = INSTR_MUL_IF;
#endif
        else
            return NULL;
    }
    return ir_block_create_binop(self, label, op, left, right);
}

ir_value* ir_block_create_div(ir_block *self,
                              const char *label,
                              ir_value *left, ir_value *right)
{
    int op = 0;
    int l = left->vtype;
    int r = right->vtype;
    if (l == r) {

        switch (l) {
            default:
                return NULL;
            case qc_float:
                op = INSTR_DIV_F;
                break;
#if 0
            case qc_int:
                op = INSTR_DIV_I;
                break;
#endif
        }
    } else {
#if 0
        if ( (l == qc_vector && r == qc_float) )
            op = INSTR_DIV_VF;
        else if ( (l == qc_float && r == qc_int) )
            op = INSTR_DIV_FI;
        else if ( (l == qc_int && r == qc_float) )
            op = INSTR_DIV_IF;
        else
#endif
            return NULL;
    }
    return ir_block_create_binop(self, label, op, left, right);
}

/* PHI resolving breaks the SSA, and must thus be the last
 * step before life-range calculation.
 */

static void ir_block_naive_phi(ir_block *self);
void ir_function_naive_phi(ir_function *self)
{
    size_t i;

    for (i = 0; i < self->blocks_count; ++i)
        ir_block_naive_phi(self->blocks[i]);
}

static void ir_naive_phi_emit_store(ir_block *block, size_t iid, ir_value *old, ir_value *what)
{
    ir_instr *instr;
    size_t i;

    /* create a store */
    ir_block_create_store(block, old, what);

    /* we now move it up */
    instr = block->instr[block->instr_count-1];
    for (i = block->instr_count; i > iid; --i)
        block->instr[i] = block->instr[i-1];
    block->instr[i] = instr;
}

static void ir_block_naive_phi(ir_block *self)
{
    size_t i, p, w;
    /* FIXME: optionally, create_phi can add the phis
     * to a list so we don't need to loop through blocks
     * - anyway: "don't optimize YET"
     */
    for (i = 0; i < self->instr_count; ++i)
    {
        ir_instr *instr = self->instr[i];
        if (instr->opcode != VINSTR_PHI)
            continue;

        ir_block_instr_remove(self, i);
        --i; /* NOTE: i+1 below */

        for (p = 0; p < instr->phi_count; ++p)
        {
            ir_value *v = instr->phi[p].value;
            for (w = 0; w < v->writes_count; ++w) {
                ir_value *old;

                if (!v->writes[w]->_ops[0])
                    continue;

                /* When the write was to a global, we have to emit a mov */
                old = v->writes[w]->_ops[0];

                /* The original instruction now writes to the PHI target local */
                if (v->writes[w]->_ops[0] == v)
                    v->writes[w]->_ops[0] = instr->_ops[0];

                if (old->store != store_local)
                {
                    /* If it originally wrote to a global we need to store the value
                     * there as welli
                     */
                    ir_naive_phi_emit_store(self, i+1, old, v);
                    if (i+1 < self->instr_count)
                        instr = self->instr[i+1];
                    else
                        instr = NULL;
                    /* In case I forget and access instr later, it'll be NULL
                     * when it's a problem, to make sure we crash, rather than accessing
                     * invalid data.
                     */
                }
                else
                {
                    /* If it didn't, we can replace all reads by the phi target now. */
                    size_t r;
                    for (r = 0; r < old->reads_count; ++r)
                    {
                        size_t op;
                        ir_instr *ri = old->reads[r];
                        for (op = 0; op < ri->phi_count; ++op) {
                            if (ri->phi[op].value == old)
                                ri->phi[op].value = v;
                        }
                        for (op = 0; op < 3; ++op) {
                            if (ri->_ops[op] == old)
                                ri->_ops[op] = v;
                        }
                    }
                }
            }
        }
        ir_instr_delete(instr);
    }
}

/***********************************************************************
 *IR Temp allocation code
 * Propagating value life ranges by walking through the function backwards
 * until no more changes are made.
 * In theory this should happen once more than once for every nested loop
 * level.
 * Though this implementation might run an additional time for if nests.
 */

typedef struct
{
    ir_value* *v;
    size_t    v_count;
    size_t    v_alloc;
} new_reads_t;
MEM_VEC_FUNCTIONS_ALL(new_reads_t, ir_value*, v)

/* Enumerate instructions used by value's life-ranges
 */
static void ir_block_enumerate(ir_block *self, size_t *_eid)
{
    size_t i;
    size_t eid = *_eid;
    for (i = 0; i < self->instr_count; ++i)
    {
        self->instr[i]->eid = eid++;
    }
    *_eid = eid;
}

/* Enumerate blocks and instructions.
 * The block-enumeration is unordered!
 * We do not really use the block enumreation, however
 * the instruction enumeration is important for life-ranges.
 */
void ir_function_enumerate(ir_function *self)
{
    size_t i;
    size_t instruction_id = 0;
    for (i = 0; i < self->blocks_count; ++i)
    {
        self->blocks[i]->eid = i;
        self->blocks[i]->run_id = 0;
        ir_block_enumerate(self->blocks[i], &instruction_id);
    }
}

static void ir_block_life_propagate(ir_block *b, ir_block *prev, bool *changed);
void ir_function_calculate_liferanges(ir_function *self)
{
    size_t i;
    bool changed;

    do {
        self->run_id++;
        changed = false;
        for (i = 0; i != self->blocks_count; ++i)
        {
            if (self->blocks[i]->is_return)
                ir_block_life_propagate(self->blocks[i], NULL, &changed);
        }
    } while (changed);
}

/* Get information about which operand
 * is read from, or written to.
 */
static void ir_op_read_write(int op, size_t *read, size_t *write)
{
    switch (op)
    {
    case VINSTR_JUMP:
    case INSTR_GOTO:
        *write = 0;
        *read = 0;
        break;
    case INSTR_IF:
    case INSTR_IFNOT:
#if 0
    case INSTR_IF_S:
    case INSTR_IFNOT_S:
#endif
    case INSTR_RETURN:
    case VINSTR_COND:
        *write = 0;
        *read = 1;
        break;
    default:
        *write = 1;
        *read = 6;
        break;
    };
}

static bool ir_block_living_add_instr(ir_block *self, size_t eid)
{
    size_t i;
    bool changed = false;
    bool tempbool;
    for (i = 0; i != self->living_count; ++i)
    {
        tempbool = ir_value_life_merge(self->living[i], eid);
        /* debug
        if (tempbool)
            fprintf(stderr, "block_living_add_instr() value instruction added %s: %i\n", self->living[i]->_name, (int)eid);
        */
        changed = changed || tempbool;
    }
    return changed;
}

static void ir_block_life_prop_previous(ir_block* self, ir_block *prev, bool *changed)
{
    size_t i;
    /* values which have been read in a previous iteration are now
     * in the "living" array even if the previous block doesn't use them.
     * So we have to remove whatever does not exist in the previous block.
     * They will be re-added on-read, but the liferange merge won't cause
     * a change.
     */
    for (i = 0; i < self->living_count; ++i)
    {
        if (!ir_block_living_find(prev, self->living[i], NULL)) {
            ir_block_living_remove(self, i);
            --i;
        }
    }

    /* Whatever the previous block still has in its living set
     * must now be added to ours as well.
     */
    for (i = 0; i < prev->living_count; ++i)
    {
        if (ir_block_living_find(self, prev->living[i], NULL))
            continue;
        ir_block_living_add(self, prev->living[i]);
        /*
        printf("%s got from prev: %s\n", self->label, prev->living[i]->_name);
        */
    }
}

static void ir_block_life_propagate(ir_block *self, ir_block *prev, bool *changed)
{
    ir_instr *instr;
    ir_value *value;
    bool  tempbool;
    size_t i, o, p, rd;
    /* bitmasks which operands are read from or written to */
    size_t read, write;
    new_reads_t new_reads;
    char dbg_ind[16] = { '#', '0' };
    (void)dbg_ind;

    MEM_VECTOR_INIT(&new_reads, v);

    if (prev)
        ir_block_life_prop_previous(self, prev, changed);

    i = self->instr_count;
    while (i)
    { --i;
        instr = self->instr[i];

        /* PHI operands are always read operands */
        for (p = 0; p < instr->phi_count; ++p)
        {
            value = instr->phi[p].value;
            /* used this before new_reads - puts the last read into the life range as well
            if (!ir_block_living_find(self, value, NULL))
                ir_block_living_add(self, value);
            */
            /* fprintf(stderr, "read: %s\n", value->_name); */
            if (!new_reads_t_v_find(&new_reads, value, NULL))
                new_reads_t_v_add(&new_reads, value);
        }

        /* See which operands are read and write operands */
        ir_op_read_write(instr->opcode, &read, &write);

        /* Go through the 3 main operands */
        for (o = 0; o < 3; ++o)
        {
            if (!instr->_ops[o]) /* no such operand */
                continue;

            value = instr->_ops[o];

            /* We only care about locals */
            if (value->store != store_value &&
                value->store != store_local)
                continue;

            /* read operands */
            if (read & (1<<o))
            {
                /* used this before new_reads - puts the last read into the life range as well
                if (!ir_block_living_find(self, value, NULL))
                    ir_block_living_add(self, value);
                */
                /* fprintf(stderr, "read: %s\n", value->_name); */
                if (!new_reads_t_v_find(&new_reads, value, NULL))
                    new_reads_t_v_add(&new_reads, value);
            }

            /* write operands */
            /* When we write to a local, we consider it "dead" for the
             * remaining upper part of the function, since in SSA a value
             * can only be written once (== created)
             */
            if (write & (1<<o))
            {
                size_t idx, readidx;
                bool in_living = ir_block_living_find(self, value, &idx);
                bool in_reads = new_reads_t_v_find(&new_reads, value, &readidx);
                if (!in_living && !in_reads)
                {
                    /* If the value isn't alive it hasn't been read before... */
                    /* TODO: See if the warning can be emitted during parsing or AST processing
                     * otherwise have warning printed here.
                     * IF printing a warning here: include filecontext_t,
                     * and make sure it's only printed once
                     * since this function is run multiple times.
                     */
                    /* For now: debug info: */
                    fprintf(stderr, "Value only written %s\n", value->name);
                    tempbool = ir_value_life_merge(value, instr->eid);
                    *changed = *changed || tempbool;
                    /*
                    ir_instr_dump(instr, dbg_ind, printf);
                    abort();
                    */
                } else {
                    /* since 'living' won't contain it
                     * anymore, merge the value, since
                     * (A) doesn't.
                     */
                    tempbool = ir_value_life_merge(value, instr->eid);
                    /*
                    if (tempbool)
                        fprintf(stderr, "value added id %s %i\n", value->name, (int)instr->eid);
                    */
                    *changed = *changed || tempbool;
                    /* Then remove */
                    ir_block_living_remove(self, idx);
                    if (in_reads)
                        new_reads_t_v_remove(&new_reads, readidx);
                }
            }
        }
        /* (A) */
        tempbool = ir_block_living_add_instr(self, instr->eid);
        //fprintf(stderr, "living added values\n");
        *changed = *changed || tempbool;

        /* new reads: */
        for (rd = 0; rd < new_reads.v_count; ++rd)
        {
            if (!ir_block_living_find(self, new_reads.v[rd], NULL)) {
                ir_block_living_add(self, new_reads.v[rd]);
            }
            if (!i && !self->entries_count) {
                /* fix the top */
                *changed = *changed || ir_value_life_merge(new_reads.v[rd], instr->eid);
            }
        }
        new_reads_t_v_clear(&new_reads);
    }

    if (self->run_id == self->owner->run_id)
        return;
    self->run_id = self->owner->run_id;

    for (i = 0; i < self->entries_count; ++i)
    {
        ir_block *entry = self->entries[i];
        ir_block_life_propagate(entry, self, changed);
    }
}