#include "optimise.h"
#include "blocks.h"
#include "flow.h"

static void removeRedundantLabels(Block b) {
    Node p, end;
    int notJump;
    end = block_lastNode(b)->x.next;
    p = block_firstNode(b);
    notJump = (p->op != JUMP + V);
    for (p = p->x.next; p != end; p = p->x.next) {
        if ((p->op == LABEL + V) && notJump) {
            p->op = NOOP;
        }
        notJump = (p->op != JUMP + V);
    }
}
/*
static Node profilerNode(int id) {
    static Symbol func;
    static Symbol address; 
    Node icnst, arg, call;
    if (func == NULL) {
        func = NEW0(func, PERM);
        func->type = ftype(voidtype, inttype);
        address = mksymbol(EXTERN, "_trace_i", func->type);
        func->defined = 0;
    }
    icnst = newnode(CNST + I + sizeop(4), NULL, NULL, intconst(id));
    arg = newnode(ARG + I + sizeop(inttype->size), icnst, NULL, intconst(inttype->size));
    arg->syms[1] = intconst(inttype->align);
    call = newnode(CALL + V, newnode(ADDRG + P + sizeop(4), NULL, NULL, address), NULL, func);
    arg->link = call;
    return arg; 
}

static void profileLabel(Block b) {
    Node p, profiler;
    int id;
    p = block_firstNode(b);
    while (p->op != LABEL + V)
        p = p->x.next;
    id = p->syms[0]->u.l.label;
    profiler = profilerNode(id);
    block_insertAtHead(b, profiler);
}
*/
static void ensureLabel(Block b) {
    Node p, end;
    p = block_firstNode(b);
    if (p->op == LABEL + V)
        return;
    if (p->op == NOOP) 
        if (p->x.next && p->x.next->op == LABEL + V)
            return;
        else {
            p->op = LABEL + V;
            p->syms[0] = findlabel(genlabel(1));
            return;   
        }
    block_insertAtHead(b, newnode(LABEL + V, NULL, NULL, findlabel(genlabel(1))));
}


/*
static char* _prof(void) {
    flow_applyToBlocks(removeRedundantLabels);
    flow_applyToBlocks(ensureLabel);
    flow_applyToBlocks(profileLabel);
    // Need to add space for profiling...
     return NULL;
}
*/
static char* _delabel(void) {
    flow_applyToBlocks(removeRedundantLabels);
     return NULL;
}

static char* _label(void) {
    flow_applyToBlocks(removeRedundantLabels);
    flow_applyToBlocks(ensureLabel);
     return NULL;
}


optimiser delabel = {
    "delabel",
    "Removes redundant labels, makes peep-hole optimiser's job easier.",
    0,
    &_delabel
};

optimiser label = {
    "label",
    "Ensures that all blocks start with a label and that no other labels exist.",
    0,
    &_label
};
/*
optimiser profile = {
    "profile",
    "Adds block level profiling information.",
    0,
    &_prof    
};
*/