MWCC/compiler_and_linker/unsorted/LiveInfo.c

#include "compiler/LiveInfo.h"
#include "compiler/BitVectors.h"
#include "compiler/Coloring.h"
#include "compiler/CompilerTools.h"
#include "compiler/PCode.h"
#include "compiler/Registers.h"
#include "compiler/objects.h"
#include "compiler/types.h"
#include "compiler/CParser.h"

LiveInfo *liveinfo;

static void allocateliveinfo(void) {
    UInt32 regs;
    LiveInfo *info;
    int i;

    regs = used_virtual_registers[coloring_class];

    liveinfo = oalloc(sizeof(LiveInfo) * pcblockcount);
    for (i = 0, info = liveinfo; i < pcblockcount; i++, info++) {
        bitvectorinitialize(info->vec0 = oalloc(4 * ((regs + 31) >> 5)), regs, 0);
        bitvectorinitialize(info->vec4 = oalloc(4 * ((regs + 31) >> 5)), regs, 0);
        bitvectorinitialize(info->vec8 = oalloc(4 * ((regs + 31) >> 5)), regs, 0);
        bitvectorinitialize(info->vecC = oalloc(4 * ((regs + 31) >> 5)), regs, 0);
    }
}

static void computelocalusedef(void) {
    LiveInfo *info;
    PCodeBlock *block;
    PCode *instr;
    UInt32 *vec0;
    UInt32 *vec4;
    PCodeArg *op;
    int i;

    for (block = pcbasicblocks; block; block = block->nextBlock) {
        info = &liveinfo[block->blockIndex];
        vec0 = info->vec0;
        vec4 = info->vec4;

        for (instr = block->firstPCode; instr; instr = instr->nextPCode) {
            op = instr->args;
            i = instr->argCount;
            while (i--) {
                if (
                    op->kind == PCOp_REGISTER &&
                    (char) op->arg == coloring_class &&
                    (op->data.reg.effect & EffectRead) &&
                    !bitvectorgetbit(op->data.reg.reg, vec4)
                    )
                    bitvectorsetbit(op->data.reg.reg, vec0);
                op++;
            }

            op = instr->args;
            i = instr->argCount;
            while (i--) {
                if (
                    op->kind == PCOp_REGISTER &&
                    (char) op->arg == coloring_class &&
                    (op->data.reg.effect & EffectWrite) &&
                    !bitvectorgetbit(op->data.reg.reg, vec0)
                    )
                    bitvectorsetbit(op->data.reg.reg, vec4);
                op++;
            }
        }
    }
}

static void computeglobalinout(void) {
    UInt32 regs;
    LiveInfo *info;
    UInt32 *vec0;
    UInt32 *vec4;
    UInt32 *vec8;
    UInt32 *vecC;
    int bitvecsize;
    int blockIndex;
    int i;
    int flag;
    PCodeBlock *block;
    PCLink *link;
    UInt32 val;

    regs = used_virtual_registers[coloring_class];
    bitvecsize = (regs + 31) >> 5;
    flag = 1;
    while (flag) {
        flag = 0;
        blockIndex = pcblockcount;
        while (blockIndex) {
            if ((block = depthfirstordering[--blockIndex])) {
                info = &liveinfo[block->blockIndex];
                if ((link = block->successors)) {
                    vecC = info->vecC;
                    bitvectorcopy(vecC, liveinfo[link->block->blockIndex].vec8, regs);
                    for (link = link->nextLink; link; link = link->nextLink)
                        bitvectorunion(vecC, liveinfo[link->block->blockIndex].vec8, regs);
                }

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

void computelivevariables(Object *proc) {
    Type *returnType;

    returnType = TYPE_FUNC(proc->type)->functype;
    computedepthfirstordering();
    allocateliveinfo();
    computelocalusedef();

    if (coloring_class == RegClass_GPR && TYPE_FITS_IN_REGISTER(returnType)) {
        bitvectorsetbit(3, liveinfo[epilogue->blockIndex].vec0);
        if (TYPE_IS_8BYTES(returnType))
            bitvectorsetbit(4, liveinfo[pclastblock->blockIndex].vec0);
    } else if (coloring_class == RegClass_FPR && IS_TYPE_FLOAT(returnType)) {
        bitvectorsetbit(1, liveinfo[epilogue->blockIndex].vec0);
    } else if (coloring_class == RegClass_VR && IS_TYPE_VECTOR(returnType)) {
        bitvectorsetbit(2, liveinfo[epilogue->blockIndex].vec0);
    }

    computeglobalinout();
}

int dead(PCode *instr, char rclass, UInt32 *vec) {
    int i;
    PCodeArg *op;

    if (instr->flags & (fPCodeFlag1 | fPCodeFlag4 | fPCodeFlag8 | fIsVolatile | fSideEffects))
        return 0;
    if (instr->block->flags & (fPCBlockFlag1 | fPCBlockFlag2))
        return 0;

    op = instr->args;
    i = instr->argCount;
    while (i--) {
        if (
            op->kind == PCOp_REGISTER &&
            (op->data.reg.effect & EffectWrite) &&
            (rclass != (char) op->arg || bitvectorgetbit(op->data.reg.reg, vec))
            )
            return 0;
        op++;
    }

    return copts.optimizationlevel > 0;
}