src/compiler/codegen/arm/Thumb2/Ralloc.cc

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

namespace art {

/*
 * This file contains codegen for the Thumb ISA and is intended to be
 * includes by:
 *
 *        Codegen-$(TARGET_ARCH_VARIANT).c
 *
 */

/*
 * Alloc a pair of core registers, or a double.  Low reg in low byte,
 * high reg in next byte.
 */
int oatAllocTypedTempPair(CompilationUnit* cUnit, bool fpHint, int regClass)
{
    int highReg;
    int lowReg;
    int res = 0;

    if (((regClass == kAnyReg) && fpHint) || (regClass == kFPReg)) {
        lowReg = oatAllocTempDouble(cUnit);
        highReg = lowReg + 1;
    } else {
        lowReg = oatAllocTemp(cUnit);
        highReg = oatAllocTemp(cUnit);
    }
    res = (lowReg & 0xff) | ((highReg & 0xff) << 8);
    return res;
}

int oatAllocTypedTemp(CompilationUnit* cUnit, bool fpHint, int regClass)
{
    if (((regClass == kAnyReg) && fpHint) || (regClass == kFPReg))
        return oatAllocTempFloat(cUnit);
    return oatAllocTemp(cUnit);
}

void oatInitializeRegAlloc(CompilationUnit* cUnit)
{
    int numRegs = sizeof(coreRegs)/sizeof(*coreRegs);
    int numReserved = sizeof(reservedRegs)/sizeof(*reservedRegs);
    int numTemps = sizeof(coreTemps)/sizeof(*coreTemps);
    int numFPRegs = sizeof(fpRegs)/sizeof(*fpRegs);
    int numFPTemps = sizeof(fpTemps)/sizeof(*fpTemps);
    RegisterPool *pool = (RegisterPool *)oatNew(cUnit, sizeof(*pool), true,
                                                kAllocRegAlloc);
    cUnit->regPool = pool;
    pool->numCoreRegs = numRegs;
    pool->coreRegs = (RegisterInfo *)
            oatNew(cUnit, numRegs * sizeof(*cUnit->regPool->coreRegs),
                   true, kAllocRegAlloc);
    pool->numFPRegs = numFPRegs;
    pool->FPRegs = (RegisterInfo *)
            oatNew(cUnit, numFPRegs * sizeof(*cUnit->regPool->FPRegs), true,
                   kAllocRegAlloc);
    oatInitPool(pool->coreRegs, coreRegs, pool->numCoreRegs);
    oatInitPool(pool->FPRegs, fpRegs, pool->numFPRegs);
    // Keep special registers from being allocated
    for (int i = 0; i < numReserved; i++) {
        if (NO_SUSPEND && !cUnit->genDebugger &&
            (reservedRegs[i] == rSUSPEND)) {
            //To measure cost of suspend check
            continue;
        }
        oatMarkInUse(cUnit, reservedRegs[i]);
    }
    // Mark temp regs - all others not in use can be used for promotion
    for (int i = 0; i < numTemps; i++) {
        oatMarkTemp(cUnit, coreTemps[i]);
    }
    for (int i = 0; i < numFPTemps; i++) {
        oatMarkTemp(cUnit, fpTemps[i]);
    }

    // Start allocation at r2 in an attempt to avoid clobbering return values
    pool->nextCoreReg = r2;

    // Construct the alias map.
    cUnit->phiAliasMap = (int*)oatNew(cUnit, cUnit->numSSARegs *
                                      sizeof(cUnit->phiAliasMap[0]), false,
                                      kAllocDFInfo);
    for (int i = 0; i < cUnit->numSSARegs; i++) {
        cUnit->phiAliasMap[i] = i;
    }
    for (MIR* phi = cUnit->phiList; phi; phi = phi->meta.phiNext) {
        int defReg = phi->ssaRep->defs[0];
        for (int i = 0; i < phi->ssaRep->numUses; i++) {
           for (int j = 0; j < cUnit->numSSARegs; j++) {
               if (cUnit->phiAliasMap[j] == phi->ssaRep->uses[i]) {
                   cUnit->phiAliasMap[j] = defReg;
               }
           }
        }
    }
}

void freeRegLocTemps(CompilationUnit* cUnit, RegLocation rlKeep,
                     RegLocation rlFree)
{
    if ((rlFree.lowReg != rlKeep.lowReg) && (rlFree.lowReg != rlKeep.highReg) &&
        (rlFree.highReg != rlKeep.lowReg) && (rlFree.highReg != rlKeep.highReg)) {
        // No overlap, free both
        oatFreeTemp(cUnit, rlFree.lowReg);
        oatFreeTemp(cUnit, rlFree.highReg);
    }
}


}  // namespace art