1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ART_COMPILER_DEX_REG_LOCATION_H_ 18 #define ART_COMPILER_DEX_REG_LOCATION_H_ 19 20 #include "reg_storage.h" 21 22 namespace art { 23 24 static constexpr int16_t INVALID_SREG = -1; 25 26 /* 27 * Whereas a SSA name describes a definition of a Dalvik vreg, the RegLocation describes 28 * the type of an SSA name (and, can also be used by code generators to record where the 29 * value is located (i.e. - physical register, frame, spill, etc.). For each SSA name (SReg) 30 * there is a RegLocation. 31 * A note on SSA names: 32 * o SSA names for Dalvik vRegs v0..vN will be assigned 0..N. These represent the "vN_0" 33 * names. Negative SSA names represent special values not present in the Dalvik byte code. 34 * For example, SSA name -1 represents an invalid SSA name, and SSA name -2 represents the 35 * the Method pointer. SSA names < -2 are reserved for future use. 36 * o The vN_0 names for non-argument Dalvik should in practice never be used (as they would 37 * represent the read of an undefined local variable). The first definition of the 38 * underlying Dalvik vReg will result in a vN_1 name. 39 * 40 * FIXME: The orig_sreg field was added as a workaround for llvm bitcode generation. With 41 * the latest restructuring, we should be able to remove it and rely on s_reg_low throughout. 42 */ 43 struct RegLocation { 44 RegLocationType location:3; 45 unsigned wide:1; 46 unsigned defined:1; // Do we know the type? 47 unsigned is_const:1; // Constant, value in mir_graph->constant_values[]. 48 unsigned fp:1; // Floating point? 49 unsigned core:1; // Non-floating point? 50 unsigned ref:1; // Something GC cares about. 51 unsigned high_word:1; // High word of pair? 52 unsigned home:1; // Does this represent the home location? 53 RegStorage reg; // Encoded physical registers. 54 int16_t s_reg_low; // SSA name for low Dalvik word. 55 int16_t orig_sreg; // TODO: remove after Bitcode gen complete 56 // and consolidate usage w/ s_reg_low. 57 }; 58 59 } // namespace art 60 61 #endif // ART_COMPILER_DEX_REG_LOCATION_H_ 62