MWCC/compiler_and_linker/unsorted/CopyPropagation.c

#include "compiler/CopyPropagation.h"
#include "compiler/CMangler.h"
#include "compiler/CParser.h"
#include "compiler/BitVectors.h"
#include "compiler/CompilerTools.h"
#include "compiler/PCode.h"
#include "compiler/PCodeListing.h"
#include "compiler/RegisterInfo.h"
#include "compiler/UseDefChains.h"

int propagatedcopies;
int propagated_instructions;
int recursive_propagation;
int number_of_candidates;
Candidate *Candidates;
PropInfo *propinfo;
int *ncandidatesinblock;
int *firstcandidateinblock;
static int moreaggressiveoptimization;
static PropagateAndFinishFunc propagateandfinish;
static PropagatesToUseFunc propagatestouse;
static IsCandidateFunc is_candidate;

static void precomputecanidatecounts(void) {
    PCodeBlock *block;
    PCode *pcode;
    int count;

    ncandidatesinblock = oalloc(sizeof(int) * pcblockcount);
    firstcandidateinblock = oalloc(sizeof(int) * pcblockcount);
    number_of_candidates = 0;

    for (block = pcbasicblocks; block; block = block->nextBlock) {
        firstcandidateinblock[block->blockIndex] = number_of_candidates;

        count = 0;
        for (pcode = block->firstPCode; pcode; pcode = pcode->nextPCode) {
            if (is_candidate(pcode)) {
                number_of_candidates++;
                count++;
            }
        }
        ncandidatesinblock[block->blockIndex] = count;
    }
}

static void computecandidatelist(void) {
    RegUseOrDef *list; // r23
    PCodeBlock *block; // r22
    PCode *pcode; // r21
    Candidate *candidate; // r20
    UInt32 *vec; // r19
    int reg;
    RegUseOrDef *newlist;
    UseOrDef *def;
    UseOrDef *use;
    int defID;
    int useID;

    Candidates = oalloc(sizeof(Candidate) * number_of_candidates);
    vec = oalloc(4 * ((number_of_Uses + 31) >> 5));

    for (block = pcbasicblocks; block; block = block->nextBlock) {
        if (ncandidatesinblock[block->blockIndex]) {
            bitvectorcopy(vec, usedefinfo[block->blockIndex].usevec1C, number_of_Uses);
            candidate = &Candidates[firstcandidateinblock[block->blockIndex] + ncandidatesinblock[block->blockIndex] - 1];
            for (pcode = block->lastPCode; pcode; pcode = pcode->prevPCode) {
                if (!(pcode->flags & fIsBranch) && pcode->argCount) {
                    if (is_candidate(pcode)) {
                        reg = pcode->args[0].data.reg.reg;
                        candidate->pcode = pcode;
                        candidate->list = NULL;

                        for (list = reg_Uses[pcode->args[0].arg][reg]; list; list = list->next) {
                            if (bitvectorgetbit(list->id, vec)) {
                                newlist = oalloc(sizeof(RegUseOrDef));
                                newlist->id = list->id;
                                newlist->next = candidate->list;
                                candidate->list = newlist;
                            }
                        }

                        if ((pcode->flags & fIsRead | fIsWrite) && (pcode->flags & fUpdatesPtr)) {
                            for (list = reg_Uses[pcode->args[1].arg][pcode->args[1].data.reg.reg]; list; list = list->next) {
                                if (bitvectorgetbit(list->id, vec)) {
                                    newlist = oalloc(sizeof(RegUseOrDef));
                                    newlist->id = list->id;
                                    newlist->next = candidate->list;
                                    candidate->list = newlist;
                                }
                            }
                        }

                        candidate--;
                    }

                    for (def = &Defs[defID = pcode->defID]; defID < number_of_Defs && def->pcode == pcode; def++, defID++) {
                        if (def->v.kind == PCOp_REGISTER) {
                            for (list = reg_Uses[def->v.arg][def->v.u.reg]; list; list = list->next)
                                bitvectorclearbit(list->id, vec);
                        }
                    }
                    for (use = &Uses[useID = pcode->useID]; useID < number_of_Uses && use->pcode == pcode; use++, useID++) {
                        if (use->v.kind == PCOp_REGISTER)
                            bitvectorsetbit(useID, vec);
                    }
                }
            }
        }
    }
}

static void allocatepropinfo(void) {
    PropInfo *info;
    int i;

    propinfo = oalloc(sizeof(PropInfo) * pcblockcount);
    for (i = 0, info = propinfo; i < pcblockcount; i++, info++) {
        info->vec0 = oalloc(4 * ((number_of_candidates + 31) >> 5));
        info->vec4 = oalloc(4 * ((number_of_candidates + 31) >> 5));
        info->vec8 = oalloc(4 * ((number_of_candidates + 31) >> 5));
        info->vecC = oalloc(4 * ((number_of_candidates + 31) >> 5));
    }
}

static void computelocalpropinfo(Boolean flag) {
    PropInfo *info;
    PCode *pcode;
    PCodeBlock *block;
    UInt32 *vec0;
    UInt32 *vec4;
    int index;
    PCodeArg *op;
    PCodeArg *candOp;
    int i;
    int j;
    int cndi;
    Candidate *candidate;

    for (block = pcbasicblocks; block; block = block->nextBlock) {
        info = &propinfo[block->blockIndex];
        vec0 = info->vec0;
        vec4 = info->vec4;
        bitvectorinitialize(vec0, number_of_candidates, 0);
        bitvectorinitialize(vec4, number_of_candidates, 0);
        index = firstcandidateinblock[block->blockIndex];

        if (flag) {
            for (pcode = block->firstPCode; pcode; pcode = pcode->nextPCode) {
                if (!(pcode->flags & fIsBranch) && pcode->argCount) {
                    i = pcode->argCount;
                    op = pcode->args;
                    while (i--) {
                        if (op->kind == PCOp_REGISTER && op->arg == RegClass_GPR && (op->data.reg.effect & EffectWrite)) {
                            for (cndi = 0, candidate = Candidates; cndi < number_of_candidates; cndi++, candidate++) {
                                for (j = 0; j < candidate->pcode->argCount; j++) {
                                    candOp = candidate->pcode->args + j;
                                    if (candOp->kind == PCOp_REGISTER && candOp->arg == RegClass_GPR && candOp->data.reg.reg == op->data.reg.reg) {
                                        if (candidate->pcode->block == block)
                                            bitvectorclearbit(cndi, vec0);
                                        else
                                            bitvectorsetbit(cndi, vec4);
                                        break;
                                    }
                                }
                            }
                        }
                        op++;
                    }

                    if (is_candidate(pcode)) {
                        bitvectorsetbit(index, vec0);
                        index++;
                    }
                }
            }
        } else {
            for (pcode = block->firstPCode; pcode; pcode = pcode->nextPCode) {
                if (!(pcode->flags & fIsBranch) && pcode->argCount) {
                    i = pcode->argCount;
                    op = pcode->args;
                    while (i--) {
                        if (op->kind == PCOp_REGISTER && (op->data.reg.effect & EffectWrite)) {
                            for (cndi = 0, candidate = Candidates; cndi < number_of_candidates; cndi++, candidate++) {
                                for (j = 0; j < candidate->pcode->argCount; j++) {
                                    candOp = candidate->pcode->args + j;
                                    if (candOp->kind == PCOp_REGISTER && candOp->arg == op->arg) {
                                        if (candOp->data.reg.reg == op->data.reg.reg) {
                                            if (candidate->pcode->block == block)
                                                bitvectorclearbit(cndi, vec0);
                                            else
                                                bitvectorsetbit(cndi, vec4);
                                            break;
                                        }
                                    } else {
                                        if (j == 0)
                                            break;
                                    }
                                }
                            }
                        }
                        op++;
                    }

                    if (is_candidate(pcode)) {
                        bitvectorsetbit(index, vec0);
                        index++;
                    }
                }
            }
        }
    }
}

static void computeglobalpropinfo(void) {
    PropInfo *info;
    PCodeBlock *block;
    int bitvecsize;
    UInt32 *vec0;
    UInt32 *vec4;
    UInt32 *vec8;
    UInt32 *vecC;
    int i;
    int blockIndex;
    int flag;
    PCLink *preds;
    UInt32 val;

    bitvecsize = (number_of_candidates + 31) >> 5;
    flag = 1;
    info = &propinfo[pcbasicblocks->blockIndex];
    bitvectorinitialize(info->vec8, number_of_candidates, 0);
    bitvectorcopy(info->vecC, info->vec0, number_of_candidates);

    for (block = pcbasicblocks->nextBlock; block; block = block->nextBlock) {
        info = &propinfo[block->blockIndex];
        vecC = info->vecC;
        vec4 = info->vec4;
        for (i = 0; i < bitvecsize; vecC++, vec4++, i++)
            *vecC = ~*vec4;
    }

    while (flag) {
        flag = 0;
        for (blockIndex = 0; blockIndex < pcblockcount; blockIndex++) {
            if (depthfirstordering[blockIndex]) {
                info = &propinfo[depthfirstordering[blockIndex]->blockIndex];
                if ((preds = depthfirstordering[blockIndex]->predecessors)) {
                    vec8 = info->vec8;
                    bitvectorcopy(vec8, propinfo[preds->block->blockIndex].vecC, number_of_candidates);
                    for (preds = preds->nextLink; preds; preds = preds->nextLink)
                        bitvectorintersect(vec8, propinfo[preds->block->blockIndex].vecC, number_of_candidates);
                }

                vecC = info->vecC;
                vec8 = info->vec8;
                vec0 = info->vec0;
                vec4 = info->vec4;
                for (i = 0; i < bitvecsize; i++) {
                    val = *vec0 | (*vec8 & ~*vec4);
                    if (val != *vecC) {
                        *vecC = val;
                        flag = 1;
                    }
                    vec8++;
                    vecC++;
                    vec4++;
                    vec0++;
                }
            }
        }
    }
}

int precedes(PCode *a, PCode *b) {
    PCode *scan;

    for (scan = a->nextPCode; scan; scan = scan->nextPCode) {
        if (scan == b)
            return 1;
    }

    return 0;
}

static int canidatepropagatestoalluses(int id) {
    RegUseOrDef *list;

    if (PCODE_FLAG_SET_F(Candidates[id].pcode) & (fRecordBit | fSideEffects))
        return 0;

    for (list = Candidates[id].list; list; list = list->next) {
        if (!propagatestouse(id, list->id))
            return 0;
    }

    return 1;
}

static void propagatecandidates(void) {
    int i;

    for (i = 0; i < number_of_candidates; i++) {
        if (canidatepropagatestoalluses(i))
            propagateandfinish(i);
    }
}

void propagateinstructions(Object *proc, Propagation *config, int passCount, Boolean localflag) {
    char buf[64];

    is_candidate = config->is_candidate;
    propagatestouse = config->propagatestouse;
    propagateandfinish = config->propagateandfinish;
    propagated_instructions = 0;

    while (1) {
        recursive_propagation = 0;
        precomputecanidatecounts();
        if (number_of_candidates <= 0) {
            freeoheap();
            if (config->computesUseDefChains)
                computeusedefchains(0);
            return;
        }

        computeusedefchains(0);
        computecandidatelist();
        allocatepropinfo();
        computelocalpropinfo(localflag);
        computedepthfirstordering();
        computeglobalpropinfo();
        propagatecandidates();
        passCount--;

        if (propagated_instructions && copts.debuglisting) {
            sprintf(buf, "AFTER %s PROPAGATION", config->name);
            pclistblocks(CMangler_GetLinkName(proc)->name, buf);
        }

        if (!passCount || !recursive_propagation) {
            if (!config->computesUseDefChains)
                freeoheap();
            return;
        }

        freeoheap();
    }
}

static int is_copy(PCode *pcode) {
    return (pcode->flags & fIsMove) && (pcode->args[0].data.reg.reg >= n_real_registers[pcode->args[0].arg]);
}

static int copypropagatestouse(int candidateID, int useID) {
    UseOrDef *use;
    short reg1;
    short reg2;
    RegClass rclass;
    PCode *pcode;
    int i;
    PCode *scan;
    PCodeArg *op;

    pcode = Candidates[candidateID].pcode;
    use = Uses + useID;
    rclass = pcode->args[0].arg;
    reg1 = pcode->args[0].data.reg.reg;
    reg2 = pcode->args[1].data.reg.reg;

    if (use->pcode->flags & fIsMove)
        return 0;

    if (rclass == RegClass_GPR && use->pcode->op == PC_RLWIMI && use->pcode->args[0].data.reg.reg == reg1)
        return 0;

    if (pcode->block == use->pcode->block && precedes(pcode, use->pcode)) {
        for (scan = pcode->nextPCode; scan && scan != use->pcode; scan = scan->nextPCode) {
            op = scan->args;
            i = scan->argCount;
            while (i--) {
                if (
                    op->kind == PCOp_REGISTER &&
                    op->arg == rclass &&
                    (op->data.reg.effect & EffectWrite) &&
                    op->data.reg.reg == reg2
                    )
                    return 0;
                op++;
            }
        }
    } else {
        if (!bitvectorgetbit(candidateID, propinfo[use->pcode->block->blockIndex].vec8))
            return 0;

        for (scan = use->pcode->block->firstPCode; scan; scan = scan->nextPCode) {
            op = scan->args;
            i = scan->argCount;
            while (i--) {
                if (
                    op->kind == PCOp_REGISTER &&
                    op->arg == rclass &&
                    (op->data.reg.effect & EffectWrite) &&
                    op->data.reg.reg == reg2
                    )
                    return 0;
                op++;
            }
            if (scan == use->pcode)
                break;
        }
    }

    return 1;
}

static void propagateandremovecopy(int id) {
    Candidate *candidate;
    RegClass rclass;
    short reg1;
    short reg2;
    RegUseOrDef *list;
    int i;
    PCodeArg *op;

    candidate = &Candidates[id];
    rclass = candidate->pcode->args[0].arg;
    reg1 = candidate->pcode->args[0].data.reg.reg;
    reg2 = candidate->pcode->args[1].data.reg.reg;

    if (rclass == RegClass_GPR && reg1 >= 32 && reg1 <= last_exception_register[RegClass_GPR])
        return;

    if (!moreaggressiveoptimization && reg2 < n_real_registers[rclass])
        return;

    for (list = candidate->list; list; list = list->next) {
        op = Uses[list->id].pcode->args;
        i = Uses[list->id].pcode->argCount;
        while (i--) {
            if (
                op->kind == PCOp_REGISTER &&
                op->arg == rclass &&
                op->data.reg.reg == reg1 &&
                (op->data.reg.effect & EffectRead)
                )
                op->data.reg.reg = reg2;
            op++;
        }
    }

    deletepcode(candidate->pcode);
    propagated_instructions = 1;
}

static Propagation copy_prop = {
    &is_copy,
    &copypropagatestouse,
    &propagateandremovecopy,
    "COPY",
    "COPIES",
    "c%" PRId32,
    0
};

void propagatecopyinstructions(Object *proc, int flag) {
    moreaggressiveoptimization = flag;
    propagateinstructions(proc, &copy_prop, 1, 0);
    propagatedcopies = propagated_instructions;
}