src/compiler/codegen/arm/CodegenCommon.cc - LeafOS-Project/android_art - Gitiles

 /*
  * 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 and support common to all supported
  * ARM variants.  It is included by:
  *
  *        Codegen-$(TARGET_ARCH_VARIANT).c
  *
  * which combines this common code with specific support found in the
  * applicable directory below this one.
  */

 /* Track exercised opcodes */
 static int opcodeCoverage[kNumPackedOpcodes];

 STATIC void setMemRefType(ArmLIR* lir, bool isLoad, int memType)
 {
     u8 *maskPtr;
     u8 mask = ENCODE_MEM;;
     DCHECK(EncodingMap[lir->opcode].flags & (IS_LOAD | IS_STORE));
     if (isLoad) {
         maskPtr = &lir->useMask;
     } else {
         maskPtr = &lir->defMask;
     }
     /* Clear out the memref flags */
     *maskPtr &= ~mask;
     /* ..and then add back the one we need */
     switch(memType) {
         case kLiteral:
             DCHECK(isLoad);
             *maskPtr |= ENCODE_LITERAL;
             break;
         case kDalvikReg:
             *maskPtr |= ENCODE_DALVIK_REG;
             break;
         case kHeapRef:
             *maskPtr |= ENCODE_HEAP_REF;
             break;
         case kMustNotAlias:
             /* Currently only loads can be marked as kMustNotAlias */
             DCHECK(!(EncodingMap[lir->opcode].flags & IS_STORE));
             *maskPtr |= ENCODE_MUST_NOT_ALIAS;
             break;
         default:
             LOG(FATAL) << "Oat: invalid memref kind - " << memType;
     }
 }

 /*
  * Mark load/store instructions that access Dalvik registers through r5FP +
  * offset.
  */
 STATIC void annotateDalvikRegAccess(ArmLIR* lir, int regId, bool isLoad)
 {
     setMemRefType(lir, isLoad, kDalvikReg);

     /*
      * Store the Dalvik register id in aliasInfo. Mark he MSB if it is a 64-bit
      * access.
      */
     lir->aliasInfo = regId;
     if (DOUBLEREG(lir->operands[0])) {
         lir->aliasInfo |= 0x80000000;
     }
 }

 /*
  * Decode the register id.
  */
 STATIC inline u8 getRegMaskCommon(int reg)
 {
     u8 seed;
     int shift;
     int regId = reg & 0x1f;

     /*
      * Each double register is equal to a pair of single-precision FP registers
      */
     seed = DOUBLEREG(reg) ? 3 : 1;
     /* FP register starts at bit position 16 */
     shift = FPREG(reg) ? kFPReg0 : 0;
     /* Expand the double register id into single offset */
     shift += regId;
     return (seed << shift);
 }

 /*
  * Mark the corresponding bit(s).
  */
 STATIC inline void setupRegMask(u8* mask, int reg)
 {
     *mask |= getRegMaskCommon(reg);
 }

 /*
  * Set up the proper fields in the resource mask
  */
 STATIC void setupResourceMasks(ArmLIR* lir)
 {
     int opcode = lir->opcode;
     int flags;

     if (opcode <= 0) {
         lir->useMask = lir->defMask = 0;
         return;
     }

     flags = EncodingMap[lir->opcode].flags;

     /* Set up the mask for resources that are updated */
     if (flags & (IS_LOAD | IS_STORE)) {
         /* Default to heap - will catch specialized classes later */
         setMemRefType(lir, flags & IS_LOAD, kHeapRef);
     }

     /*
      * Conservatively assume the branch here will call out a function that in
      * turn will trash everything.
      */
     if (flags & IS_BRANCH) {
         lir->defMask = lir->useMask = ENCODE_ALL;
         return;
     }

     if (flags & REG_DEF0) {
         setupRegMask(&lir->defMask, lir->operands[0]);
     }

     if (flags & REG_DEF1) {
         setupRegMask(&lir->defMask, lir->operands[1]);
     }

     if (flags & REG_DEF_SP) {
         lir->defMask |= ENCODE_REG_SP;
     }

     if (flags & REG_DEF_LR) {
         lir->defMask |= ENCODE_REG_LR;
     }

     if (flags & REG_DEF_LIST0) {
         lir->defMask |= ENCODE_REG_LIST(lir->operands[0]);
     }

     if (flags & REG_DEF_LIST1) {
         lir->defMask |= ENCODE_REG_LIST(lir->operands[1]);
     }

     if (flags & REG_DEF_FPCS_LIST0) {
         lir->defMask |= ENCODE_REG_FPCS_LIST(lir->operands[0]);
     }

     if (flags & REG_DEF_FPCS_LIST2) {
         for (int i = 0; i < lir->operands[2]; i++) {
             setupRegMask(&lir->defMask, lir->operands[1] + i);
         }
     }

     if (flags & SETS_CCODES) {
         lir->defMask |= ENCODE_CCODE;
     }

     /* Conservatively treat the IT block */
     if (flags & IS_IT) {
         lir->defMask = ENCODE_ALL;
     }

     if (flags & (REG_USE0 | REG_USE1 | REG_USE2 | REG_USE3)) {
         int i;

         for (i = 0; i < 4; i++) {
             if (flags & (1 << (kRegUse0 + i))) {
                 setupRegMask(&lir->useMask, lir->operands[i]);
             }
         }
     }

     if (flags & REG_USE_PC) {
         lir->useMask |= ENCODE_REG_PC;
     }

     if (flags & REG_USE_SP) {
         lir->useMask |= ENCODE_REG_SP;
     }

     if (flags & REG_USE_LIST0) {
         lir->useMask |= ENCODE_REG_LIST(lir->operands[0]);
     }

     if (flags & REG_USE_LIST1) {
         lir->useMask |= ENCODE_REG_LIST(lir->operands[1]);
     }

     if (flags & REG_USE_FPCS_LIST0) {
         lir->useMask |= ENCODE_REG_FPCS_LIST(lir->operands[0]);
     }

     if (flags & REG_USE_FPCS_LIST2) {
         for (int i = 0; i < lir->operands[2]; i++) {
             setupRegMask(&lir->useMask, lir->operands[1] + i);
         }
     }

     if (flags & USES_CCODES) {
         lir->useMask |= ENCODE_CCODE;
     }

     /* Fixup for kThumbPush/lr and kThumbPop/pc */
     if (opcode == kThumbPush || opcode == kThumbPop) {
         u8 r8Mask = getRegMaskCommon(r8);
         if ((opcode == kThumbPush) && (lir->useMask & r8Mask)) {
             lir->useMask &= ~r8Mask;
             lir->useMask |= ENCODE_REG_LR;
         } else if ((opcode == kThumbPop) && (lir->defMask & r8Mask)) {
             lir->defMask &= ~r8Mask;
             lir->defMask |= ENCODE_REG_PC;
         }
     }
 }

 /*
  * The following are building blocks to construct low-level IRs with 0 - 4
  * operands.
  */
 STATIC ArmLIR* newLIR0(CompilationUnit* cUnit, ArmOpcode opcode)
 {
     ArmLIR* insn = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
     DCHECK(isPseudoOpcode(opcode) || (EncodingMap[opcode].flags & NO_OPERAND));
     insn->opcode = opcode;
     setupResourceMasks(insn);
     insn->generic.dalvikOffset = cUnit->currentDalvikOffset;
     oatAppendLIR(cUnit, (LIR*) insn);
     return insn;
 }

 STATIC ArmLIR* newLIR1(CompilationUnit* cUnit, ArmOpcode opcode,
                            int dest)
 {
     ArmLIR* insn = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
     DCHECK(isPseudoOpcode(opcode) || (EncodingMap[opcode].flags & IS_UNARY_OP));
     insn->opcode = opcode;
     insn->operands[0] = dest;
     setupResourceMasks(insn);
     insn->generic.dalvikOffset = cUnit->currentDalvikOffset;
     oatAppendLIR(cUnit, (LIR*) insn);
     return insn;
 }

 STATIC ArmLIR* newLIR2(CompilationUnit* cUnit, ArmOpcode opcode,
                            int dest, int src1)
 {
     ArmLIR* insn = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
     DCHECK(isPseudoOpcode(opcode) ||
            (EncodingMap[opcode].flags & IS_BINARY_OP));
     insn->opcode = opcode;
     insn->operands[0] = dest;
     insn->operands[1] = src1;
     setupResourceMasks(insn);
     insn->generic.dalvikOffset = cUnit->currentDalvikOffset;
     oatAppendLIR(cUnit, (LIR*) insn);
     return insn;
 }

 STATIC ArmLIR* newLIR3(CompilationUnit* cUnit, ArmOpcode opcode,
                            int dest, int src1, int src2)
 {
     ArmLIR* insn = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
     DCHECK(isPseudoOpcode(opcode) ||
            (EncodingMap[opcode].flags & IS_TERTIARY_OP))
             << (int)opcode << " "
             << PrettyMethod(cUnit->method_idx, *cUnit->dex_file) << " "
             << cUnit->currentDalvikOffset;
     insn->opcode = opcode;
     insn->operands[0] = dest;
     insn->operands[1] = src1;
     insn->operands[2] = src2;
     setupResourceMasks(insn);
     insn->generic.dalvikOffset = cUnit->currentDalvikOffset;
     oatAppendLIR(cUnit, (LIR*) insn);
     return insn;
 }

 #if defined(_ARMV7_A) || defined(_ARMV7_A_NEON)
 STATIC ArmLIR* newLIR4(CompilationUnit* cUnit, ArmOpcode opcode,
                            int dest, int src1, int src2, int info)
 {
     ArmLIR* insn = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
     DCHECK(isPseudoOpcode(opcode) ||
            (EncodingMap[opcode].flags & IS_QUAD_OP));
     insn->opcode = opcode;
     insn->operands[0] = dest;
     insn->operands[1] = src1;
     insn->operands[2] = src2;
     insn->operands[3] = info;
     setupResourceMasks(insn);
     insn->generic.dalvikOffset = cUnit->currentDalvikOffset;
     oatAppendLIR(cUnit, (LIR*) insn);
     return insn;
 }
 #endif

 /*
  * Search the existing constants in the literal pool for an exact or close match
  * within specified delta (greater or equal to 0).
  */
 STATIC ArmLIR* scanLiteralPool(LIR* dataTarget, int value, unsigned int delta)
 {
     while (dataTarget) {
         if (((unsigned) (value - ((ArmLIR* ) dataTarget)->operands[0])) <=
             delta)
             return (ArmLIR* ) dataTarget;
         dataTarget = dataTarget->next;
     }
     return NULL;
 }

 /* Search the existing constants in the literal pool for an exact wide match */
 STATIC ArmLIR* scanLiteralPoolWide(LIR* dataTarget, int valLo, int valHi)
 {
     bool loMatch = false;
     LIR* loTarget = NULL;
     while (dataTarget) {
         if (loMatch && (((ArmLIR*)dataTarget)->operands[0] == valHi)) {
             return (ArmLIR*)loTarget;
         }
         loMatch = false;
         if (((ArmLIR*)dataTarget)->operands[0] == valLo) {
             loMatch = true;
             loTarget = dataTarget;
         }
         dataTarget = dataTarget->next;
     }
     return NULL;
 }

 /*
  * The following are building blocks to insert constants into the pool or
  * instruction streams.
  */

 /* Add a 32-bit constant either in the constant pool or mixed with code */
 STATIC ArmLIR* addWordData(CompilationUnit* cUnit, LIR* *constantListP,
                            int value)
 {
     /* Add the constant to the literal pool */
     if (constantListP) {
         ArmLIR* newValue = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
         newValue->operands[0] = value;
         newValue->generic.next = *constantListP;
         *constantListP = (LIR*) newValue;
         return newValue;
     } else {
         /* Add the constant in the middle of code stream */
         newLIR1(cUnit, kArm16BitData, (value & 0xffff));
         newLIR1(cUnit, kArm16BitData, (value >> 16));
     }
     return NULL;
 }

 /* Add a 64-bit constant to the constant pool or mixed with code */
 STATIC ArmLIR* addWideData(CompilationUnit* cUnit, LIR* *constantListP,
                            int valLo, int valHi)
 {
     ArmLIR* res;
     //NOTE: hard-coded little endian
     if (constantListP == NULL) {
         res = addWordData(cUnit, NULL, valLo);
         addWordData(cUnit, NULL, valHi);
     } else {
         // Insert high word into list first
         addWordData(cUnit, constantListP, valHi);
         res = addWordData(cUnit, constantListP, valLo);
     }
     return res;
 }

 /*
  * Generate an kArmPseudoBarrier marker to indicate the boundary of special
  * blocks.
  */
 STATIC void genBarrier(CompilationUnit* cUnit)
 {
     ArmLIR* barrier = newLIR0(cUnit, kArmPseudoBarrier);
     /* Mark all resources as being clobbered */
     barrier->defMask = -1;
 }

 }  // namespace art
	/*
	* 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 and support common to all supported
	* ARM variants. It is included by:
	*
	* Codegen-$(TARGET_ARCH_VARIANT).c
	*
	* which combines this common code with specific support found in the
	* applicable directory below this one.
	*/

	/* Track exercised opcodes */
	static int opcodeCoverage[kNumPackedOpcodes];

	STATIC void setMemRefType(ArmLIR* lir, bool isLoad, int memType)
	{
	u8 *maskPtr;
	u8 mask = ENCODE_MEM;;
	DCHECK(EncodingMap[lir->opcode].flags & (IS_LOAD \| IS_STORE));
	if (isLoad) {
	maskPtr = &lir->useMask;
	} else {
	maskPtr = &lir->defMask;
	}
	/* Clear out the memref flags */
	*maskPtr &= ~mask;
	/* ..and then add back the one we need */
	switch(memType) {
	case kLiteral:
	DCHECK(isLoad);
	*maskPtr \|= ENCODE_LITERAL;
	break;
	case kDalvikReg:
	*maskPtr \|= ENCODE_DALVIK_REG;
	break;
	case kHeapRef:
	*maskPtr \|= ENCODE_HEAP_REF;
	break;
	case kMustNotAlias:
	/* Currently only loads can be marked as kMustNotAlias */
	DCHECK(!(EncodingMap[lir->opcode].flags & IS_STORE));
	*maskPtr \|= ENCODE_MUST_NOT_ALIAS;
	break;
	default:
	LOG(FATAL) << "Oat: invalid memref kind - " << memType;
	}
	}

	/*
	* Mark load/store instructions that access Dalvik registers through r5FP +
	* offset.
	*/
	STATIC void annotateDalvikRegAccess(ArmLIR* lir, int regId, bool isLoad)
	{
	setMemRefType(lir, isLoad, kDalvikReg);

	/*
	* Store the Dalvik register id in aliasInfo. Mark he MSB if it is a 64-bit
	* access.
	*/
	lir->aliasInfo = regId;
	if (DOUBLEREG(lir->operands[0])) {
	lir->aliasInfo \|= 0x80000000;
	}
	}

	/*
	* Decode the register id.
	*/
	STATIC inline u8 getRegMaskCommon(int reg)
	{
	u8 seed;
	int shift;
	int regId = reg & 0x1f;

	/*
	* Each double register is equal to a pair of single-precision FP registers
	*/
	seed = DOUBLEREG(reg) ? 3 : 1;
	/* FP register starts at bit position 16 */
	shift = FPREG(reg) ? kFPReg0 : 0;
	/* Expand the double register id into single offset */
	shift += regId;
	return (seed << shift);
	}

	/*
	* Mark the corresponding bit(s).
	*/
	STATIC inline void setupRegMask(u8* mask, int reg)
	{
	*mask \|= getRegMaskCommon(reg);
	}

	/*
	* Set up the proper fields in the resource mask
	*/
	STATIC void setupResourceMasks(ArmLIR* lir)
	{
	int opcode = lir->opcode;
	int flags;

	if (opcode <= 0) {
	lir->useMask = lir->defMask = 0;
	return;
	}

	flags = EncodingMap[lir->opcode].flags;

	/* Set up the mask for resources that are updated */
	if (flags & (IS_LOAD \| IS_STORE)) {
	/* Default to heap - will catch specialized classes later */
	setMemRefType(lir, flags & IS_LOAD, kHeapRef);
	}

	/*
	* Conservatively assume the branch here will call out a function that in
	* turn will trash everything.
	*/
	if (flags & IS_BRANCH) {
	lir->defMask = lir->useMask = ENCODE_ALL;
	return;
	}

	if (flags & REG_DEF0) {
	setupRegMask(&lir->defMask, lir->operands[0]);
	}

	if (flags & REG_DEF1) {
	setupRegMask(&lir->defMask, lir->operands[1]);
	}

	if (flags & REG_DEF_SP) {
	lir->defMask \|= ENCODE_REG_SP;
	}

	if (flags & REG_DEF_LR) {
	lir->defMask \|= ENCODE_REG_LR;
	}

	if (flags & REG_DEF_LIST0) {
	lir->defMask \|= ENCODE_REG_LIST(lir->operands[0]);
	}

	if (flags & REG_DEF_LIST1) {
	lir->defMask \|= ENCODE_REG_LIST(lir->operands[1]);
	}

	if (flags & REG_DEF_FPCS_LIST0) {
	lir->defMask \|= ENCODE_REG_FPCS_LIST(lir->operands[0]);
	}

	if (flags & REG_DEF_FPCS_LIST2) {
	for (int i = 0; i < lir->operands[2]; i++) {
	setupRegMask(&lir->defMask, lir->operands[1] + i);
	}
	}

	if (flags & SETS_CCODES) {
	lir->defMask \|= ENCODE_CCODE;
	}

	/* Conservatively treat the IT block */
	if (flags & IS_IT) {
	lir->defMask = ENCODE_ALL;
	}

	if (flags & (REG_USE0 \| REG_USE1 \| REG_USE2 \| REG_USE3)) {
	int i;

	for (i = 0; i < 4; i++) {
	if (flags & (1 << (kRegUse0 + i))) {
	setupRegMask(&lir->useMask, lir->operands[i]);
	}
	}
	}

	if (flags & REG_USE_PC) {
	lir->useMask \|= ENCODE_REG_PC;
	}

	if (flags & REG_USE_SP) {
	lir->useMask \|= ENCODE_REG_SP;
	}

	if (flags & REG_USE_LIST0) {
	lir->useMask \|= ENCODE_REG_LIST(lir->operands[0]);
	}

	if (flags & REG_USE_LIST1) {
	lir->useMask \|= ENCODE_REG_LIST(lir->operands[1]);
	}

	if (flags & REG_USE_FPCS_LIST0) {
	lir->useMask \|= ENCODE_REG_FPCS_LIST(lir->operands[0]);
	}

	if (flags & REG_USE_FPCS_LIST2) {
	for (int i = 0; i < lir->operands[2]; i++) {
	setupRegMask(&lir->useMask, lir->operands[1] + i);
	}
	}

	if (flags & USES_CCODES) {
	lir->useMask \|= ENCODE_CCODE;
	}

	/* Fixup for kThumbPush/lr and kThumbPop/pc */
	if (opcode == kThumbPush \|\| opcode == kThumbPop) {
	u8 r8Mask = getRegMaskCommon(r8);
	if ((opcode == kThumbPush) && (lir->useMask & r8Mask)) {
	lir->useMask &= ~r8Mask;
	lir->useMask \|= ENCODE_REG_LR;
	} else if ((opcode == kThumbPop) && (lir->defMask & r8Mask)) {
	lir->defMask &= ~r8Mask;
	lir->defMask \|= ENCODE_REG_PC;
	}
	}
	}

	/*
	* The following are building blocks to construct low-level IRs with 0 - 4
	* operands.
	*/
	STATIC ArmLIR* newLIR0(CompilationUnit* cUnit, ArmOpcode opcode)
	{
	ArmLIR* insn = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
	DCHECK(isPseudoOpcode(opcode) \|\| (EncodingMap[opcode].flags & NO_OPERAND));
	insn->opcode = opcode;
	setupResourceMasks(insn);
	insn->generic.dalvikOffset = cUnit->currentDalvikOffset;
	oatAppendLIR(cUnit, (LIR*) insn);
	return insn;
	}

	STATIC ArmLIR* newLIR1(CompilationUnit* cUnit, ArmOpcode opcode,
	int dest)
	{
	ArmLIR* insn = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
	DCHECK(isPseudoOpcode(opcode) \|\| (EncodingMap[opcode].flags & IS_UNARY_OP));
	insn->opcode = opcode;
	insn->operands[0] = dest;
	setupResourceMasks(insn);
	insn->generic.dalvikOffset = cUnit->currentDalvikOffset;
	oatAppendLIR(cUnit, (LIR*) insn);
	return insn;
	}

	STATIC ArmLIR* newLIR2(CompilationUnit* cUnit, ArmOpcode opcode,
	int dest, int src1)
	{
	ArmLIR* insn = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
	DCHECK(isPseudoOpcode(opcode) \|\|
	(EncodingMap[opcode].flags & IS_BINARY_OP));
	insn->opcode = opcode;
	insn->operands[0] = dest;
	insn->operands[1] = src1;
	setupResourceMasks(insn);
	insn->generic.dalvikOffset = cUnit->currentDalvikOffset;
	oatAppendLIR(cUnit, (LIR*) insn);
	return insn;
	}

	STATIC ArmLIR* newLIR3(CompilationUnit* cUnit, ArmOpcode opcode,
	int dest, int src1, int src2)
	{
	ArmLIR* insn = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
	DCHECK(isPseudoOpcode(opcode) \|\|
	(EncodingMap[opcode].flags & IS_TERTIARY_OP))
	<< (int)opcode << " "
	<< PrettyMethod(cUnit->method_idx, *cUnit->dex_file) << " "
	<< cUnit->currentDalvikOffset;
	insn->opcode = opcode;
	insn->operands[0] = dest;
	insn->operands[1] = src1;
	insn->operands[2] = src2;
	setupResourceMasks(insn);
	insn->generic.dalvikOffset = cUnit->currentDalvikOffset;
	oatAppendLIR(cUnit, (LIR*) insn);
	return insn;
	}

	#if defined(_ARMV7_A) \|\| defined(_ARMV7_A_NEON)
	STATIC ArmLIR* newLIR4(CompilationUnit* cUnit, ArmOpcode opcode,
	int dest, int src1, int src2, int info)
	{
	ArmLIR* insn = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
	DCHECK(isPseudoOpcode(opcode) \|\|
	(EncodingMap[opcode].flags & IS_QUAD_OP));
	insn->opcode = opcode;
	insn->operands[0] = dest;
	insn->operands[1] = src1;
	insn->operands[2] = src2;
	insn->operands[3] = info;
	setupResourceMasks(insn);
	insn->generic.dalvikOffset = cUnit->currentDalvikOffset;
	oatAppendLIR(cUnit, (LIR*) insn);
	return insn;
	}
	#endif

	/*
	* Search the existing constants in the literal pool for an exact or close match
	* within specified delta (greater or equal to 0).
	*/
	STATIC ArmLIR* scanLiteralPool(LIR* dataTarget, int value, unsigned int delta)
	{
	while (dataTarget) {
	if (((unsigned) (value - ((ArmLIR* ) dataTarget)->operands[0])) <=
	delta)
	return (ArmLIR* ) dataTarget;
	dataTarget = dataTarget->next;
	}
	return NULL;
	}

	/* Search the existing constants in the literal pool for an exact wide match */
	STATIC ArmLIR* scanLiteralPoolWide(LIR* dataTarget, int valLo, int valHi)
	{
	bool loMatch = false;
	LIR* loTarget = NULL;
	while (dataTarget) {
	if (loMatch && (((ArmLIR*)dataTarget)->operands[0] == valHi)) {
	return (ArmLIR*)loTarget;
	}
	loMatch = false;
	if (((ArmLIR*)dataTarget)->operands[0] == valLo) {
	loMatch = true;
	loTarget = dataTarget;
	}
	dataTarget = dataTarget->next;
	}
	return NULL;
	}

	/*
	* The following are building blocks to insert constants into the pool or
	* instruction streams.
	*/

	/* Add a 32-bit constant either in the constant pool or mixed with code */
	STATIC ArmLIR* addWordData(CompilationUnit* cUnit, LIR* *constantListP,
	int value)
	{
	/* Add the constant to the literal pool */
	if (constantListP) {
	ArmLIR* newValue = (ArmLIR* ) oatNew(sizeof(ArmLIR), true);
	newValue->operands[0] = value;
	newValue->generic.next = *constantListP;
	constantListP = (LIR) newValue;
	return newValue;
	} else {
	/* Add the constant in the middle of code stream */
	newLIR1(cUnit, kArm16BitData, (value & 0xffff));
	newLIR1(cUnit, kArm16BitData, (value >> 16));
	}
	return NULL;
	}

	/* Add a 64-bit constant to the constant pool or mixed with code */
	STATIC ArmLIR* addWideData(CompilationUnit* cUnit, LIR* *constantListP,
	int valLo, int valHi)
	{
	ArmLIR* res;
	//NOTE: hard-coded little endian
	if (constantListP == NULL) {
	res = addWordData(cUnit, NULL, valLo);
	addWordData(cUnit, NULL, valHi);
	} else {
	// Insert high word into list first
	addWordData(cUnit, constantListP, valHi);
	res = addWordData(cUnit, constantListP, valLo);
	}
	return res;
	}

	/*
	* Generate an kArmPseudoBarrier marker to indicate the boundary of special
	* blocks.
	*/
	STATIC void genBarrier(CompilationUnit* cUnit)
	{
	ArmLIR* barrier = newLIR0(cUnit, kArmPseudoBarrier);
	/* Mark all resources as being clobbered */
	barrier->defMask = -1;
	}

	} // namespace art