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      1 /*
      2  * Copyright (C) 2011 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_RUNTIME_ARCH_INSTRUCTION_SET_H_
     18 #define ART_RUNTIME_ARCH_INSTRUCTION_SET_H_
     19 
     20 #include <iosfwd>
     21 #include <string>
     22 
     23 #include "base/enums.h"
     24 #include "base/macros.h"
     25 
     26 namespace art {
     27 
     28 enum InstructionSet {
     29   kNone,
     30   kArm,
     31   kArm64,
     32   kThumb2,
     33   kX86,
     34   kX86_64,
     35   kMips,
     36   kMips64
     37 };
     38 std::ostream& operator<<(std::ostream& os, const InstructionSet& rhs);
     39 
     40 #if defined(__arm__)
     41 static constexpr InstructionSet kRuntimeISA = kArm;
     42 #elif defined(__aarch64__)
     43 static constexpr InstructionSet kRuntimeISA = kArm64;
     44 #elif defined(__mips__) && !defined(__LP64__)
     45 static constexpr InstructionSet kRuntimeISA = kMips;
     46 #elif defined(__mips__) && defined(__LP64__)
     47 static constexpr InstructionSet kRuntimeISA = kMips64;
     48 #elif defined(__i386__)
     49 static constexpr InstructionSet kRuntimeISA = kX86;
     50 #elif defined(__x86_64__)
     51 static constexpr InstructionSet kRuntimeISA = kX86_64;
     52 #else
     53 static constexpr InstructionSet kRuntimeISA = kNone;
     54 #endif
     55 
     56 // Architecture-specific pointer sizes
     57 static constexpr PointerSize kArmPointerSize = PointerSize::k32;
     58 static constexpr PointerSize kArm64PointerSize = PointerSize::k64;
     59 static constexpr PointerSize kMipsPointerSize = PointerSize::k32;
     60 static constexpr PointerSize kMips64PointerSize = PointerSize::k64;
     61 static constexpr PointerSize kX86PointerSize = PointerSize::k32;
     62 static constexpr PointerSize kX86_64PointerSize = PointerSize::k64;
     63 
     64 // ARM instruction alignment. ARM processors require code to be 4-byte aligned,
     65 // but ARM ELF requires 8..
     66 static constexpr size_t kArmAlignment = 8;
     67 
     68 // ARM64 instruction alignment. This is the recommended alignment for maximum performance.
     69 static constexpr size_t kArm64Alignment = 16;
     70 
     71 // MIPS instruction alignment.  MIPS processors require code to be 4-byte aligned,
     72 // but 64-bit literals must be 8-byte aligned.
     73 static constexpr size_t kMipsAlignment = 8;
     74 
     75 // X86 instruction alignment. This is the recommended alignment for maximum performance.
     76 static constexpr size_t kX86Alignment = 16;
     77 
     78 // Different than code alignment since code alignment is only first instruction of method.
     79 static constexpr size_t kThumb2InstructionAlignment = 2;
     80 static constexpr size_t kArm64InstructionAlignment = 4;
     81 static constexpr size_t kX86InstructionAlignment = 1;
     82 static constexpr size_t kX86_64InstructionAlignment = 1;
     83 static constexpr size_t kMipsInstructionAlignment = 4;
     84 static constexpr size_t kMips64InstructionAlignment = 4;
     85 
     86 const char* GetInstructionSetString(InstructionSet isa);
     87 
     88 // Note: Returns kNone when the string cannot be parsed to a known value.
     89 InstructionSet GetInstructionSetFromString(const char* instruction_set);
     90 
     91 InstructionSet GetInstructionSetFromELF(uint16_t e_machine, uint32_t e_flags);
     92 
     93 // Fatal logging out of line to keep the header clean of logging.h.
     94 NO_RETURN void InstructionSetAbort(InstructionSet isa);
     95 
     96 static inline PointerSize GetInstructionSetPointerSize(InstructionSet isa) {
     97   switch (isa) {
     98     case kArm:
     99       // Fall-through.
    100     case kThumb2:
    101       return kArmPointerSize;
    102     case kArm64:
    103       return kArm64PointerSize;
    104     case kX86:
    105       return kX86PointerSize;
    106     case kX86_64:
    107       return kX86_64PointerSize;
    108     case kMips:
    109       return kMipsPointerSize;
    110     case kMips64:
    111       return kMips64PointerSize;
    112     default:
    113       InstructionSetAbort(isa);
    114   }
    115 }
    116 
    117 ALWAYS_INLINE static inline constexpr size_t GetInstructionSetInstructionAlignment(
    118     InstructionSet isa) {
    119   return (isa == kThumb2 || isa == kArm) ? kThumb2InstructionAlignment :
    120          (isa == kArm64) ? kArm64InstructionAlignment :
    121          (isa == kX86) ? kX86InstructionAlignment :
    122          (isa == kX86_64) ? kX86_64InstructionAlignment :
    123          (isa == kMips) ? kMipsInstructionAlignment :
    124          (isa == kMips64) ? kMips64InstructionAlignment :
    125          0;  // Invalid case, but constexpr doesn't support asserts.
    126 }
    127 
    128 static inline bool IsValidInstructionSet(InstructionSet isa) {
    129   switch (isa) {
    130     case kArm:
    131     case kThumb2:
    132     case kArm64:
    133     case kX86:
    134     case kX86_64:
    135     case kMips:
    136     case kMips64:
    137       return true;
    138     case kNone:
    139     default:
    140       return false;
    141   }
    142 }
    143 
    144 size_t GetInstructionSetAlignment(InstructionSet isa);
    145 
    146 static inline bool Is64BitInstructionSet(InstructionSet isa) {
    147   switch (isa) {
    148     case kArm:
    149     case kThumb2:
    150     case kX86:
    151     case kMips:
    152       return false;
    153 
    154     case kArm64:
    155     case kX86_64:
    156     case kMips64:
    157       return true;
    158 
    159     default:
    160       InstructionSetAbort(isa);
    161   }
    162 }
    163 
    164 static inline PointerSize InstructionSetPointerSize(InstructionSet isa) {
    165   return Is64BitInstructionSet(isa) ? PointerSize::k64 : PointerSize::k32;
    166 }
    167 
    168 static inline size_t GetBytesPerGprSpillLocation(InstructionSet isa) {
    169   switch (isa) {
    170     case kArm:
    171       // Fall-through.
    172     case kThumb2:
    173       return 4;
    174     case kArm64:
    175       return 8;
    176     case kX86:
    177       return 4;
    178     case kX86_64:
    179       return 8;
    180     case kMips:
    181       return 4;
    182     case kMips64:
    183       return 8;
    184 
    185     default:
    186       InstructionSetAbort(isa);
    187   }
    188 }
    189 
    190 static inline size_t GetBytesPerFprSpillLocation(InstructionSet isa) {
    191   switch (isa) {
    192     case kArm:
    193       // Fall-through.
    194     case kThumb2:
    195       return 4;
    196     case kArm64:
    197       return 8;
    198     case kX86:
    199       return 8;
    200     case kX86_64:
    201       return 8;
    202     case kMips:
    203       return 4;
    204     case kMips64:
    205       return 8;
    206 
    207     default:
    208       InstructionSetAbort(isa);
    209   }
    210 }
    211 
    212 size_t GetStackOverflowReservedBytes(InstructionSet isa);
    213 
    214 // The following definitions create return types for two word-sized entities that will be passed
    215 // in registers so that memory operations for the interface trampolines can be avoided. The entities
    216 // are the resolved method and the pointer to the code to be invoked.
    217 //
    218 // On x86, ARM32 and MIPS, this is given for a *scalar* 64bit value. The definition thus *must* be
    219 // uint64_t or long long int.
    220 //
    221 // On x86_64, ARM64 and MIPS64, structs are decomposed for allocation, so we can create a structs of
    222 // two size_t-sized values.
    223 //
    224 // We need two operations:
    225 //
    226 // 1) A flag value that signals failure. The assembly stubs expect the lower part to be "0".
    227 //    GetTwoWordFailureValue() will return a value that has lower part == 0.
    228 //
    229 // 2) A value that combines two word-sized values.
    230 //    GetTwoWordSuccessValue() constructs this.
    231 //
    232 // IMPORTANT: If you use this to transfer object pointers, it is your responsibility to ensure
    233 //            that the object does not move or the value is updated. Simple use of this is NOT SAFE
    234 //            when the garbage collector can move objects concurrently. Ensure that required locks
    235 //            are held when using!
    236 
    237 #if defined(__i386__) || defined(__arm__) || (defined(__mips__) && !defined(__LP64__))
    238 typedef uint64_t TwoWordReturn;
    239 
    240 // Encodes method_ptr==nullptr and code_ptr==nullptr
    241 static inline constexpr TwoWordReturn GetTwoWordFailureValue() {
    242   return 0;
    243 }
    244 
    245 // Use the lower 32b for the method pointer and the upper 32b for the code pointer.
    246 static inline TwoWordReturn GetTwoWordSuccessValue(uintptr_t hi, uintptr_t lo) {
    247   static_assert(sizeof(uint32_t) == sizeof(uintptr_t), "Unexpected size difference");
    248   uint32_t lo32 = lo;
    249   uint64_t hi64 = static_cast<uint64_t>(hi);
    250   return ((hi64 << 32) | lo32);
    251 }
    252 
    253 #elif defined(__x86_64__) || defined(__aarch64__) || (defined(__mips__) && defined(__LP64__))
    254 struct TwoWordReturn {
    255   uintptr_t lo;
    256   uintptr_t hi;
    257 };
    258 
    259 // Encodes method_ptr==nullptr. Leaves random value in code pointer.
    260 static inline TwoWordReturn GetTwoWordFailureValue() {
    261   TwoWordReturn ret;
    262   ret.lo = 0;
    263   return ret;
    264 }
    265 
    266 // Write values into their respective members.
    267 static inline TwoWordReturn GetTwoWordSuccessValue(uintptr_t hi, uintptr_t lo) {
    268   TwoWordReturn ret;
    269   ret.lo = lo;
    270   ret.hi = hi;
    271   return ret;
    272 }
    273 #else
    274 #error "Unsupported architecture"
    275 #endif
    276 
    277 }  // namespace art
    278 
    279 #endif  // ART_RUNTIME_ARCH_INSTRUCTION_SET_H_
    280