Basic block optimization refactoring
Various optimization improvements for the common frontend.
Before applying basic block optimizations, split the graph
into extended basic blocks. Replace existing pattern-match
range-check elimination with a scheme based on local value
numbering (which could also serve as the basis for some CSE
if the existing, but so-far untested, common frontend temp
register mechanism works as designed).
For the framework, this CL improves null check elimination
from 90.74% (statically) to 91.24% removed, and range
check elimination from 3.45% to 8.17%.
Change-Id: Ie1ce730cfe12a12fef665a30fe3814bad1993895
diff --git a/src/compiler/bb_opt.cc b/src/compiler/bb_opt.cc
new file mode 100644
index 0000000..3ad5821
--- /dev/null
+++ b/src/compiler/bb_opt.cc
@@ -0,0 +1,519 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#include "bb_opt.h"
+#include "dataflow.h"
+
+namespace art {
+
+
+uint16_t BBOpt::GetValueNumber(MIR* mir)
+{
+ uint16_t res = NO_VALUE;
+ uint16_t opcode = mir->dalvikInsn.opcode;
+ switch (opcode) {
+ case Instruction::NOP:
+ case Instruction::RETURN_VOID:
+ case Instruction::RETURN:
+ case Instruction::RETURN_OBJECT:
+ case Instruction::RETURN_WIDE:
+ case Instruction::MONITOR_ENTER:
+ case Instruction::MONITOR_EXIT:
+ case Instruction::GOTO:
+ case Instruction::GOTO_16:
+ case Instruction::GOTO_32:
+ case Instruction::CHECK_CAST:
+ case Instruction::THROW:
+ case Instruction::FILL_ARRAY_DATA:
+ case Instruction::FILLED_NEW_ARRAY:
+ case Instruction::FILLED_NEW_ARRAY_RANGE:
+ case Instruction::PACKED_SWITCH:
+ case Instruction::SPARSE_SWITCH:
+ case Instruction::IF_EQ:
+ case Instruction::IF_NE:
+ case Instruction::IF_LT:
+ case Instruction::IF_GE:
+ case Instruction::IF_GT:
+ case Instruction::IF_LE:
+ case Instruction::IF_EQZ:
+ case Instruction::IF_NEZ:
+ case Instruction::IF_LTZ:
+ case Instruction::IF_GEZ:
+ case Instruction::IF_GTZ:
+ case Instruction::IF_LEZ:
+ case Instruction::INVOKE_STATIC_RANGE:
+ case Instruction::INVOKE_STATIC:
+ case Instruction::INVOKE_DIRECT:
+ case Instruction::INVOKE_DIRECT_RANGE:
+ case Instruction::INVOKE_VIRTUAL:
+ case Instruction::INVOKE_VIRTUAL_RANGE:
+ case Instruction::INVOKE_SUPER:
+ case Instruction::INVOKE_SUPER_RANGE:
+ case Instruction::INVOKE_INTERFACE:
+ case Instruction::INVOKE_INTERFACE_RANGE:
+ case kMirOpFusedCmplFloat:
+ case kMirOpFusedCmpgFloat:
+ case kMirOpFusedCmplDouble:
+ case kMirOpFusedCmpgDouble:
+ case kMirOpFusedCmpLong:
+ // Nothing defined - take no action.
+ break;
+
+ case Instruction::MOVE_EXCEPTION:
+ case Instruction::MOVE_RESULT:
+ case Instruction::MOVE_RESULT_OBJECT:
+ case Instruction::INSTANCE_OF:
+ case Instruction::NEW_INSTANCE:
+ case Instruction::CONST_STRING:
+ case Instruction::CONST_STRING_JUMBO:
+ case Instruction::CONST_CLASS:
+ case Instruction::NEW_ARRAY: {
+ // 1 result, treat as unique each time, use result s_reg - will be unique.
+ uint16_t res = GetOperandValue(mir->ssa_rep->defs[0]);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+ case Instruction::MOVE_RESULT_WIDE: {
+ // 1 wide result, treat as unique each time, use result s_reg - will be unique.
+ uint16_t res = GetOperandValueWide(mir->ssa_rep->defs[0]);
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case kMirOpPhi:
+ /*
+ * Because we'll only see phi nodes at the beginning of an extended basic block,
+ * we can ignore them. Revisit if we shift to global value numbering.
+ */
+ break;
+
+ case Instruction::MOVE:
+ case Instruction::MOVE_OBJECT:
+ case Instruction::MOVE_16:
+ case Instruction::MOVE_OBJECT_16:
+ case Instruction::MOVE_FROM16:
+ case Instruction::MOVE_OBJECT_FROM16:
+ case kMirOpCopy: {
+ // Just copy value number of source to value number of resulit.
+ uint16_t res = GetOperandValue(mir->ssa_rep->uses[0]);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::MOVE_WIDE:
+ case Instruction::MOVE_WIDE_16:
+ case Instruction::MOVE_WIDE_FROM16: {
+ // Just copy value number of source to value number of result.
+ uint16_t res = GetOperandValueWide(mir->ssa_rep->uses[0]);
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::CONST:
+ case Instruction::CONST_4:
+ case Instruction::CONST_16: {
+ uint16_t res = LookupValue(Instruction::CONST, Low16Bits(mir->dalvikInsn.vB),
+ High16Bits(mir->dalvikInsn.vB >> 16), 0);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::CONST_HIGH16: {
+ uint16_t res = LookupValue(Instruction::CONST, 0, mir->dalvikInsn.vB, 0);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::CONST_WIDE_16:
+ case Instruction::CONST_WIDE_32: {
+ uint16_t low_res = LookupValue(Instruction::CONST, Low16Bits(mir->dalvikInsn.vB),
+ High16Bits(mir->dalvikInsn.vB >> 16), 1);
+ uint16_t high_res;
+ if (mir->dalvikInsn.vB & 0x80000000) {
+ high_res = LookupValue(Instruction::CONST, 0xffff, 0xffff, 2);
+ } else {
+ high_res = LookupValue(Instruction::CONST, 0, 0, 2);
+ }
+ uint16_t res = LookupValue(Instruction::CONST, low_res, high_res, 3);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::CONST_WIDE: {
+ uint32_t low_word = Low32Bits(mir->dalvikInsn.vB_wide);
+ uint32_t high_word = High32Bits(mir->dalvikInsn.vB_wide);
+ uint16_t low_res = LookupValue(Instruction::CONST, Low16Bits(low_word),
+ High16Bits(low_word), 1);
+ uint16_t high_res = LookupValue(Instruction::CONST, Low16Bits(high_word),
+ High16Bits(high_word), 2);
+ uint16_t res = LookupValue(Instruction::CONST, low_res, high_res, 3);
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::CONST_WIDE_HIGH16: {
+ uint16_t low_res = LookupValue(Instruction::CONST, 0, 0, 1);
+ uint16_t high_res = LookupValue(Instruction::CONST, 0, Low16Bits(mir->dalvikInsn.vB), 2);
+ uint16_t res = LookupValue(Instruction::CONST, low_res, high_res, 3);
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::ARRAY_LENGTH:
+ case Instruction::NEG_INT:
+ case Instruction::NOT_INT:
+ case Instruction::NEG_FLOAT:
+ case Instruction::INT_TO_BYTE:
+ case Instruction::INT_TO_SHORT:
+ case Instruction::INT_TO_CHAR:
+ case Instruction::INT_TO_FLOAT:
+ case Instruction::FLOAT_TO_INT: {
+ // res = op + 1 operand
+ uint16_t operand1 = GetOperandValue(mir->ssa_rep->uses[0]);
+ uint16_t res = LookupValue(opcode, operand1, NO_VALUE, NO_VALUE);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::LONG_TO_FLOAT:
+ case Instruction::LONG_TO_INT:
+ case Instruction::DOUBLE_TO_FLOAT:
+ case Instruction::DOUBLE_TO_INT: {
+ // res = op + 1 wide operand
+ uint16_t operand1 = GetOperandValue(mir->ssa_rep->uses[0]);
+ uint16_t res = LookupValue(opcode, operand1, NO_VALUE, NO_VALUE);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+
+ case Instruction::DOUBLE_TO_LONG:
+ case Instruction::LONG_TO_DOUBLE:
+ case Instruction::NEG_LONG:
+ case Instruction::NOT_LONG:
+ case Instruction::NEG_DOUBLE: {
+ // wide res = op + 1 wide operand
+ uint16_t operand1 = GetOperandValueWide(mir->ssa_rep->uses[0]);
+ uint16_t res = LookupValue(opcode, operand1, NO_VALUE, NO_VALUE);
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::FLOAT_TO_DOUBLE:
+ case Instruction::FLOAT_TO_LONG:
+ case Instruction::INT_TO_DOUBLE:
+ case Instruction::INT_TO_LONG: {
+ // wide res = op + 1 operand
+ uint16_t operand1 = GetOperandValueWide(mir->ssa_rep->uses[0]);
+ uint16_t res = LookupValue(opcode, operand1, NO_VALUE, NO_VALUE);
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::CMPL_DOUBLE:
+ case Instruction::CMPG_DOUBLE:
+ case Instruction::CMP_LONG: {
+ // res = op + 2 wide operands
+ uint16_t operand1 = GetOperandValueWide(mir->ssa_rep->uses[0]);
+ uint16_t operand2 = GetOperandValueWide(mir->ssa_rep->uses[2]);
+ uint16_t res = LookupValue(opcode, operand1, operand2, NO_VALUE);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::CMPG_FLOAT:
+ case Instruction::CMPL_FLOAT:
+ case Instruction::ADD_INT:
+ case Instruction::ADD_INT_2ADDR:
+ case Instruction::MUL_INT:
+ case Instruction::MUL_INT_2ADDR:
+ case Instruction::AND_INT:
+ case Instruction::AND_INT_2ADDR:
+ case Instruction::OR_INT:
+ case Instruction::OR_INT_2ADDR:
+ case Instruction::XOR_INT:
+ case Instruction::XOR_INT_2ADDR:
+ case Instruction::SUB_INT:
+ case Instruction::SUB_INT_2ADDR:
+ case Instruction::DIV_INT:
+ case Instruction::DIV_INT_2ADDR:
+ case Instruction::REM_INT:
+ case Instruction::REM_INT_2ADDR:
+ case Instruction::SHL_INT:
+ case Instruction::SHL_INT_2ADDR:
+ case Instruction::SHR_INT:
+ case Instruction::SHR_INT_2ADDR:
+ case Instruction::USHR_INT:
+ case Instruction::USHR_INT_2ADDR: {
+ // res = op + 2 operands
+ uint16_t operand1 = GetOperandValue(mir->ssa_rep->uses[0]);
+ uint16_t operand2 = GetOperandValue(mir->ssa_rep->uses[1]);
+ uint16_t res = LookupValue(opcode, operand1, operand2, NO_VALUE);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::ADD_LONG:
+ case Instruction::SUB_LONG:
+ case Instruction::MUL_LONG:
+ case Instruction::DIV_LONG:
+ case Instruction::REM_LONG:
+ case Instruction::AND_LONG:
+ case Instruction::OR_LONG:
+ case Instruction::XOR_LONG:
+ case Instruction::ADD_LONG_2ADDR:
+ case Instruction::SUB_LONG_2ADDR:
+ case Instruction::MUL_LONG_2ADDR:
+ case Instruction::DIV_LONG_2ADDR:
+ case Instruction::REM_LONG_2ADDR:
+ case Instruction::AND_LONG_2ADDR:
+ case Instruction::OR_LONG_2ADDR:
+ case Instruction::XOR_LONG_2ADDR:
+ case Instruction::ADD_DOUBLE:
+ case Instruction::SUB_DOUBLE:
+ case Instruction::MUL_DOUBLE:
+ case Instruction::DIV_DOUBLE:
+ case Instruction::REM_DOUBLE:
+ case Instruction::ADD_DOUBLE_2ADDR:
+ case Instruction::SUB_DOUBLE_2ADDR:
+ case Instruction::MUL_DOUBLE_2ADDR:
+ case Instruction::DIV_DOUBLE_2ADDR:
+ case Instruction::REM_DOUBLE_2ADDR: {
+ // wide res = op + 2 wide operands
+ uint16_t operand1 = GetOperandValueWide(mir->ssa_rep->uses[0]);
+ uint16_t operand2 = GetOperandValueWide(mir->ssa_rep->uses[2]);
+ uint16_t res = LookupValue(opcode, operand1, operand2, NO_VALUE);
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::SHL_LONG:
+ case Instruction::SHR_LONG:
+ case Instruction::USHR_LONG:
+ case Instruction::SHL_LONG_2ADDR:
+ case Instruction::SHR_LONG_2ADDR:
+ case Instruction::USHR_LONG_2ADDR: {
+ // wide res = op + 1 wide operand + 1 operand
+ uint16_t operand1 = GetOperandValueWide(mir->ssa_rep->uses[0]);
+ uint16_t operand2 = GetOperandValueWide(mir->ssa_rep->uses[2]);
+ uint16_t res = LookupValue(opcode, operand1, operand2, NO_VALUE);
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::ADD_FLOAT:
+ case Instruction::SUB_FLOAT:
+ case Instruction::MUL_FLOAT:
+ case Instruction::DIV_FLOAT:
+ case Instruction::REM_FLOAT:
+ case Instruction::ADD_FLOAT_2ADDR:
+ case Instruction::SUB_FLOAT_2ADDR:
+ case Instruction::MUL_FLOAT_2ADDR:
+ case Instruction::DIV_FLOAT_2ADDR:
+ case Instruction::REM_FLOAT_2ADDR: {
+ // res = op + 2 operands
+ uint16_t operand1 = GetOperandValue(mir->ssa_rep->uses[0]);
+ uint16_t operand2 = GetOperandValue(mir->ssa_rep->uses[1]);
+ uint16_t res = LookupValue(opcode, operand1, operand2, NO_VALUE);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::RSUB_INT:
+ case Instruction::ADD_INT_LIT16:
+ case Instruction::MUL_INT_LIT16:
+ case Instruction::DIV_INT_LIT16:
+ case Instruction::REM_INT_LIT16:
+ case Instruction::AND_INT_LIT16:
+ case Instruction::OR_INT_LIT16:
+ case Instruction::XOR_INT_LIT16:
+ case Instruction::ADD_INT_LIT8:
+ case Instruction::RSUB_INT_LIT8:
+ case Instruction::MUL_INT_LIT8:
+ case Instruction::DIV_INT_LIT8:
+ case Instruction::REM_INT_LIT8:
+ case Instruction::AND_INT_LIT8:
+ case Instruction::OR_INT_LIT8:
+ case Instruction::XOR_INT_LIT8:
+ case Instruction::SHL_INT_LIT8:
+ case Instruction::SHR_INT_LIT8:
+ case Instruction::USHR_INT_LIT8: {
+ // Same as res = op + 2 operands, except use vB as operand 2
+ uint16_t operand1 = GetOperandValue(mir->ssa_rep->uses[0]);
+ uint16_t operand2 = LookupValue(Instruction::CONST, mir->dalvikInsn.vB, 0, 0);
+ uint16_t res = LookupValue(opcode, operand1, operand2, NO_VALUE);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ break;
+
+ case Instruction::AGET_WIDE:
+ case Instruction::AGET:
+ case Instruction::AGET_OBJECT:
+ case Instruction::AGET_BOOLEAN:
+ case Instruction::AGET_BYTE:
+ case Instruction::AGET_CHAR:
+ case Instruction::AGET_SHORT: {
+ uint16_t array = GetOperandValue(mir->ssa_rep->uses[0]);
+ if (null_checked_.find(array) != null_checked_.end()) {
+ if (cu_->verbose) {
+ LOG(INFO) << "Removing null check for 0x" << std::hex << mir->offset;
+ }
+ mir->optimization_flags |= MIR_IGNORE_NULL_CHECK;
+ } else {
+ null_checked_.insert(array);
+ }
+ uint16_t index = GetOperandValue(mir->ssa_rep->uses[1]);
+ if (ValueExists(ARRAY_REF, array, index, NO_VALUE)) {
+ if (cu_->verbose) {
+ LOG(INFO) << "Removing range check for 0x" << std::hex << mir->offset;
+ }
+ mir->optimization_flags |= MIR_IGNORE_RANGE_CHECK;
+ }
+ mir->meta.throw_insn->optimization_flags |= mir->optimization_flags;
+ // Use side effect to note range check completed.
+ (void)LookupValue(ARRAY_REF, array, index, NO_VALUE);
+ // Establish value number for loaded register. Note use of memory version.
+ uint16_t memory_version = GetMemoryVersion(array, NO_VALUE);
+ uint16_t res = LookupValue(ARRAY_REF, array, index, memory_version);
+ if (opcode == Instruction::AGET_WIDE) {
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ } else {
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ }
+ break;
+
+ case Instruction::APUT_WIDE:
+ case Instruction::APUT:
+ case Instruction::APUT_OBJECT:
+ case Instruction::APUT_SHORT:
+ case Instruction::APUT_CHAR:
+ case Instruction::APUT_BYTE:
+ case Instruction::APUT_BOOLEAN: {
+ int array_idx = (opcode == Instruction::APUT_WIDE) ? 2 : 1;
+ int index_idx = array_idx + 1;
+ uint16_t array = GetOperandValue(mir->ssa_rep->uses[array_idx]);
+ if (null_checked_.find(array) != null_checked_.end()) {
+ if (cu_->verbose) {
+ LOG(INFO) << "Removing range check for 0x" << std::hex << mir->offset;
+ }
+ mir->optimization_flags |= MIR_IGNORE_NULL_CHECK;
+ } else {
+ null_checked_.insert(array);
+ }
+ uint16_t index = GetOperandValue(mir->ssa_rep->uses[index_idx]);
+ if (ValueExists(ARRAY_REF, array, index, NO_VALUE)) {
+ if (cu_->verbose) {
+ LOG(INFO) << "Removing range check for 0x" << std::hex << mir->offset;
+ }
+ mir->optimization_flags |= MIR_IGNORE_RANGE_CHECK;
+ }
+ mir->meta.throw_insn->optimization_flags |= mir->optimization_flags;
+ // Use side effect to note range check completed.
+ (void)LookupValue(ARRAY_REF, array, index, NO_VALUE);
+ // Rev the memory version
+ AdvanceMemoryVersion(array, NO_VALUE);
+ }
+ break;
+
+ case Instruction::IGET_OBJECT:
+ case Instruction::IGET_WIDE:
+ case Instruction::IGET:
+ case Instruction::IGET_CHAR:
+ case Instruction::IGET_SHORT:
+ case Instruction::IGET_BOOLEAN:
+ case Instruction::IGET_BYTE: {
+ uint16_t base = GetOperandValue(mir->ssa_rep->uses[0]);
+ if (null_checked_.find(base) != null_checked_.end()) {
+ if (cu_->verbose) {
+ LOG(INFO) << "Removing null check for 0x" << std::hex << mir->offset;
+ }
+ mir->optimization_flags |= MIR_IGNORE_NULL_CHECK;
+ } else {
+ null_checked_.insert(base);
+ }
+ mir->meta.throw_insn->optimization_flags |= mir->optimization_flags;
+ uint16_t field_ref = mir->dalvikInsn.vC;
+ uint16_t memory_version = GetMemoryVersion(base, field_ref);
+ if (opcode == Instruction::IGET_WIDE) {
+ uint16_t res = LookupValue(Instruction::IGET_WIDE, base, field_ref, memory_version);
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ } else {
+ uint16_t res = LookupValue(Instruction::IGET, base, field_ref, memory_version);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ }
+ break;
+
+ case Instruction::IPUT_WIDE:
+ case Instruction::IPUT_OBJECT:
+ case Instruction::IPUT:
+ case Instruction::IPUT_BOOLEAN:
+ case Instruction::IPUT_BYTE:
+ case Instruction::IPUT_CHAR:
+ case Instruction::IPUT_SHORT: {
+ int base_reg = (opcode == Instruction::IPUT_WIDE) ? 2 : 1;
+ uint16_t base = GetOperandValue(mir->ssa_rep->uses[base_reg]);
+ if (null_checked_.find(base) != null_checked_.end()) {
+ if (cu_->verbose) {
+ LOG(INFO) << "Removing null check for 0x" << std::hex << mir->offset;
+ }
+ mir->optimization_flags |= MIR_IGNORE_NULL_CHECK;
+ } else {
+ null_checked_.insert(base);
+ }
+ mir->meta.throw_insn->optimization_flags |= mir->optimization_flags;
+ uint16_t field_ref = mir->dalvikInsn.vC;
+ AdvanceMemoryVersion(base, field_ref);
+ }
+ break;
+
+ case Instruction::SGET_OBJECT:
+ case Instruction::SGET:
+ case Instruction::SGET_BOOLEAN:
+ case Instruction::SGET_BYTE:
+ case Instruction::SGET_CHAR:
+ case Instruction::SGET_SHORT:
+ case Instruction::SGET_WIDE: {
+ uint16_t field_ref = mir->dalvikInsn.vB;
+ uint16_t memory_version = GetMemoryVersion(NO_VALUE, field_ref);
+ if (opcode == Instruction::SGET_WIDE) {
+ uint16_t res = LookupValue(Instruction::SGET_WIDE, NO_VALUE, field_ref, memory_version);
+ SetOperandValueWide(mir->ssa_rep->defs[0], res);
+ } else {
+ uint16_t res = LookupValue(Instruction::SGET, NO_VALUE, field_ref, memory_version);
+ SetOperandValue(mir->ssa_rep->defs[0], res);
+ }
+ }
+ break;
+
+ case Instruction::SPUT_OBJECT:
+ case Instruction::SPUT:
+ case Instruction::SPUT_BOOLEAN:
+ case Instruction::SPUT_BYTE:
+ case Instruction::SPUT_CHAR:
+ case Instruction::SPUT_SHORT:
+ case Instruction::SPUT_WIDE: {
+ uint16_t field_ref = mir->dalvikInsn.vB;
+ AdvanceMemoryVersion(NO_VALUE, field_ref);
+ }
+ break;
+
+ }
+ return res;
+}
+
+} // namespace art