#include "CompilerTools.h"
#include "PCode.h"

// TODO RESOLVE ME
extern void initialize_aliases();
extern void *current_statement;
extern PCode *vformatpcode(short op, va_list args);

PCBlock *pcbasicblocks;
PCBlock *pclastblock;
void *prologue;
void *epilogue;
PCBlock **depthfirstordering;
int pcblockcount;
int pcloopweight;
static unsigned short pclabelcount;

void initpcode() {
    pclastblock = 0;
    pcbasicblocks = 0;
    pcblockcount = 0;
    pclabelcount = 0;
    pcloopweight = 1;
    initialize_aliases();
}

PCode *makepcode(short op, ...) {
    PCode *pcode;
    va_list list;

    va_start(list, op);
    pcode = vformatpcode(op, list);
    // TODO
    return pcode;
}

void emitpcode(short op, ...) {
    PCode *pcode;
    va_list list;

    va_start(list, op);
    pcode = vformatpcode(op, list);
    // TODO
    appendpcode(pclastblock, pcode);
}

PCode *copypcode(PCode *pcode) {
    PCode *newpc;
    int flag;

    flag = 0;
    // TODO

    return newpc;
}

PCLabel *makepclabel() {
    PCLabel *label;

    label = (PCLabel *) lalloc(sizeof(PCLabel));
    memclrw(label, sizeof(PCLabel));
    label->index = pclabelcount++;
    return label;
}

PCBlock *makepcblock() {
    PCBlock *block;

    block = (PCBlock *) lalloc(sizeof(PCBlock));
    memclrw(block, sizeof(PCBlock));
    block->loopWeight = pcloopweight;
    block->blockIndex = pcblockcount++;
    if (pclastblock) {
        pclastblock->nextBlock = block;
        block->prevBlock = pclastblock;
    } else {
        pcbasicblocks = block;
    }
    pclastblock = block;
    return block;
}

void pclabel(PCBlock *block, PCLabel *label) {
    PCLink *iter;
    PCLink *next;

    iter = (PCLink *) label->block;
    while (iter) {
        next = (PCLink *) iter->block;
        iter->block = block;
        iter = next;
    }

    label->block = block;
    label->resolved = 1;
    label->nextLabel = block->labels;
    block->labels = label;
}

void pcbranch(PCBlock *block, PCLabel *label) {
    PCLink *link;

    link = (PCLink *) lalloc(sizeof(PCLink));
    memclrw(link, sizeof(PCLink));

    link->block = label->block;
    if (!label->resolved)
        label->block = (PCBlock *) link;
    link->nextLink = block->successors;
    block->successors = link;
}

void pccomputepredecessors() {
    PCBlock *block;
    PCLink *succ;
    PCLink *pred;

    for (block = pcbasicblocks; block; block = block->nextBlock) {
        for (succ = block->successors; succ; succ = succ->nextLink) {
            pred = (PCLink *) lalloc(sizeof(PCLink));
            memclrw(pred, sizeof(PCLink));

            pred->block = block;
            pred->nextLink = succ->block->predecessors;
            succ->block->predecessors = pred;
        }
    }
}

void deleteblock(PCBlock *block) {
    block->prevBlock->nextBlock = block->nextBlock;
    if (block->nextBlock)
        block->nextBlock->prevBlock = block->prevBlock;
    block->flags |= fPCBlockFlag20;
}

void deleteunreachableblocks() {
    PCBlock *block;

    computedepthfirstordering();

    for (block = pcbasicblocks->nextBlock; block; block = block->nextBlock) {
        if (!(block->flags & fPCBlockFlag4))
            deleteblock(block);
    }
}

void appendpcode(PCBlock *block, PCode *pcode) {
    if (block->firstPCode) {
        pcode->nextPCode = 0;
        pcode->prevPCode = block->lastPCode;
        block->lastPCode->nextPCode = pcode;
        block->lastPCode = pcode;
    } else {
        block->lastPCode = pcode;
        block->firstPCode = pcode;
        pcode->prevPCode = 0;
        pcode->nextPCode = 0;
    }
    pcode->block = block;
    block->pcodeCount++;
}

void deletepcode(PCode *pcode) {
    PCBlock *block;

    block = pcode->block;
    if (pcode->prevPCode)
        pcode->prevPCode->nextPCode = pcode->nextPCode;
    else
        block->firstPCode = pcode->nextPCode;
    if (pcode->nextPCode)
        pcode->nextPCode->prevPCode = pcode->prevPCode;
    else
        block->lastPCode = pcode->prevPCode;

    pcode->block = 0;
    block->pcodeCount--;
    block->flags &= ~fPCBlockFlag8;
}

void insertpcodebefore(PCode *anchor, PCode *newpcode) {
    PCBlock *block;

    block = anchor->block;
    if (anchor->prevPCode)
        anchor->prevPCode->nextPCode = newpcode;
    else
        block->firstPCode = newpcode;
    newpcode->nextPCode = anchor;
    newpcode->prevPCode = anchor->prevPCode;
    anchor->prevPCode = newpcode;
    newpcode->_1C = anchor->_1C;

    newpcode->block = block;
    block->pcodeCount++;
    block->flags &= ~fPCBlockFlag8;
}

void insertpcodeafter(PCode *anchor, PCode *newpcode) {
    PCBlock *block;

    block = anchor->block;
    if (anchor->nextPCode)
        anchor->nextPCode->prevPCode = newpcode;
    else
        block->lastPCode = newpcode;
    newpcode->prevPCode = anchor;
    newpcode->nextPCode = anchor->nextPCode;
    anchor->nextPCode = newpcode;
    newpcode->_1C = anchor->_1C;

    newpcode->block = block;
    block->pcodeCount++;
    block->flags &= ~fPCBlockFlag8;
}

void setpcodeflags(int flags) {
    pclastblock->lastPCode->flags |= flags;
    if (flags & fSideEffects)
        pclastblock->lastPCode->flags &= ~(fIsCSE | fCommutative | fPCodeFlag10);
}

void clearpcodeflags(int flags) {
    pclastblock->lastPCode->flags &= ~flags;
}

int pccomputeoffsets() {
    int offset;
    PCBlock *block;

    offset = 0;
    for (block = pcbasicblocks; block; block = block->nextBlock) {
        block->codeOffset = offset;
        offset += block->pcodeCount * 4;
    }

    return offset;
}

typedef struct _DFO {
    PCBlock *block;
    PCLink *link;
} DFO;

static int depthfirstorder;

void computedepthfirstordering() {
    PCBlock *block;
    PCLink *link;
    DFO *dfo;
    int index;

    depthfirstordering = (PCBlock **) lalloc(sizeof(PCBlock *) * pcblockcount);
    memclrw(depthfirstordering, sizeof(PCBlock *) * pcblockcount);
    depthfirstorder = pcblockcount;

    for (block = pcbasicblocks; block; block = block->nextBlock) {
        block->flags &= ~fPCBlockFlag4;
    }

    dfo = (DFO *) oalloc(sizeof(DFO) * pcblockcount);
    pcbasicblocks->flags |= fPCBlockFlag4;

    dfo->block = pcbasicblocks;
    dfo->link = pcbasicblocks->successors;
    index = 1;
    while (index) {
        if ((link = dfo[index - 1].link)) {
            dfo[index - 1].link = link->nextLink;
            block = link->block;
            if (!(block->flags & fPCBlockFlag4)) {
                block->flags |= fPCBlockFlag4;
                dfo[index].block = block;
                dfo[index].link = block->successors;
                index++;
            }
        } else {
            depthfirstordering[--depthfirstorder] = dfo[--index].block;
        }
    }

    while (depthfirstorder) {
        depthfirstordering[--depthfirstorder] = 0;
    }
}