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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 #include "assembler.h"
     18 
     19 #include <algorithm>
     20 #include <vector>
     21 
     22 #include "arm/assembler_arm.h"
     23 #include "mips/assembler_mips.h"
     24 #include "x86/assembler_x86.h"
     25 #include "globals.h"
     26 #include "memory_region.h"
     27 
     28 namespace art {
     29 
     30 static byte* NewContents(size_t capacity) {
     31   return new byte[capacity];
     32 }
     33 
     34 
     35 AssemblerBuffer::AssemblerBuffer() {
     36   static const size_t kInitialBufferCapacity = 4 * KB;
     37   contents_ = NewContents(kInitialBufferCapacity);
     38   cursor_ = contents_;
     39   limit_ = ComputeLimit(contents_, kInitialBufferCapacity);
     40   fixup_ = NULL;
     41   slow_path_ = NULL;
     42 #ifndef NDEBUG
     43   has_ensured_capacity_ = false;
     44   fixups_processed_ = false;
     45 #endif
     46 
     47   // Verify internal state.
     48   CHECK_EQ(Capacity(), kInitialBufferCapacity);
     49   CHECK_EQ(Size(), 0U);
     50 }
     51 
     52 
     53 AssemblerBuffer::~AssemblerBuffer() {
     54   delete[] contents_;
     55 }
     56 
     57 
     58 void AssemblerBuffer::ProcessFixups(const MemoryRegion& region) {
     59   AssemblerFixup* fixup = fixup_;
     60   while (fixup != NULL) {
     61     fixup->Process(region, fixup->position());
     62     fixup = fixup->previous();
     63   }
     64 }
     65 
     66 
     67 void AssemblerBuffer::FinalizeInstructions(const MemoryRegion& instructions) {
     68   // Copy the instructions from the buffer.
     69   MemoryRegion from(reinterpret_cast<void*>(contents()), Size());
     70   instructions.CopyFrom(0, from);
     71   // Process fixups in the instructions.
     72   ProcessFixups(instructions);
     73 #ifndef NDEBUG
     74   fixups_processed_ = true;
     75 #endif
     76 }
     77 
     78 
     79 void AssemblerBuffer::ExtendCapacity() {
     80   size_t old_size = Size();
     81   size_t old_capacity = Capacity();
     82   size_t new_capacity = std::min(old_capacity * 2, old_capacity + 1 * MB);
     83 
     84   // Allocate the new data area and copy contents of the old one to it.
     85   byte* new_contents = NewContents(new_capacity);
     86   memmove(reinterpret_cast<void*>(new_contents),
     87           reinterpret_cast<void*>(contents_),
     88           old_size);
     89 
     90   // Compute the relocation delta and switch to the new contents area.
     91   ptrdiff_t delta = new_contents - contents_;
     92   contents_ = new_contents;
     93 
     94   // Update the cursor and recompute the limit.
     95   cursor_ += delta;
     96   limit_ = ComputeLimit(new_contents, new_capacity);
     97 
     98   // Verify internal state.
     99   CHECK_EQ(Capacity(), new_capacity);
    100   CHECK_EQ(Size(), old_size);
    101 }
    102 
    103 
    104 Assembler* Assembler::Create(InstructionSet instruction_set) {
    105   switch (instruction_set) {
    106     case kArm:
    107     case kThumb2:
    108       return new arm::ArmAssembler();
    109     case kMips:
    110       return new mips::MipsAssembler();
    111     case kX86:
    112       return new x86::X86Assembler();
    113     default:
    114       LOG(FATAL) << "Unknown InstructionSet: " << instruction_set;
    115       return NULL;
    116   }
    117 }
    118 
    119 }  // namespace art
    120