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      1 //===-- llvm/CodeGen/ObjectCodeEmitter.cpp -------------------- -*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #include "llvm/CodeGen/BinaryObject.h"
     11 #include "llvm/CodeGen/MachineBasicBlock.h"
     12 #include "llvm/CodeGen/MachineRelocation.h"
     13 #include "llvm/CodeGen/ObjectCodeEmitter.h"
     14 
     15 //===----------------------------------------------------------------------===//
     16 //                       ObjectCodeEmitter Implementation
     17 //===----------------------------------------------------------------------===//
     18 
     19 namespace llvm {
     20 
     21 ObjectCodeEmitter::ObjectCodeEmitter() : BO(0) {}
     22 ObjectCodeEmitter::ObjectCodeEmitter(BinaryObject *bo) : BO(bo) {}
     23 ObjectCodeEmitter::~ObjectCodeEmitter() {}
     24 
     25 /// setBinaryObject - set the BinaryObject we are writting to
     26 void ObjectCodeEmitter::setBinaryObject(BinaryObject *bo) { BO = bo; }
     27 
     28 /// emitByte - This callback is invoked when a byte needs to be
     29 /// written to the data stream, without buffer overflow testing.
     30 void ObjectCodeEmitter::emitByte(uint8_t B) {
     31   BO->emitByte(B);
     32 }
     33 
     34 /// emitWordLE - This callback is invoked when a 32-bit word needs to be
     35 /// written to the data stream in little-endian format.
     36 void ObjectCodeEmitter::emitWordLE(uint32_t W) {
     37   BO->emitWordLE(W);
     38 }
     39 
     40 /// emitWordBE - This callback is invoked when a 32-bit word needs to be
     41 /// written to the data stream in big-endian format.
     42 void ObjectCodeEmitter::emitWordBE(uint32_t W) {
     43   BO->emitWordBE(W);
     44 }
     45 
     46 /// emitDWordLE - This callback is invoked when a 64-bit word needs to be
     47 /// written to the data stream in little-endian format.
     48 void ObjectCodeEmitter::emitDWordLE(uint64_t W) {
     49   BO->emitDWordLE(W);
     50 }
     51 
     52 /// emitDWordBE - This callback is invoked when a 64-bit word needs to be
     53 /// written to the data stream in big-endian format.
     54 void ObjectCodeEmitter::emitDWordBE(uint64_t W) {
     55   BO->emitDWordBE(W);
     56 }
     57 
     58 /// emitAlignment - Align 'BO' to the necessary alignment boundary.
     59 void ObjectCodeEmitter::emitAlignment(unsigned Alignment /* 0 */,
     60                                       uint8_t fill /* 0 */) {
     61   BO->emitAlignment(Alignment, fill);
     62 }
     63 
     64 /// emitULEB128Bytes - This callback is invoked when a ULEB128 needs to be
     65 /// written to the data stream.
     66 void ObjectCodeEmitter::emitULEB128Bytes(uint64_t Value) {
     67   BO->emitULEB128Bytes(Value);
     68 }
     69 
     70 /// emitSLEB128Bytes - This callback is invoked when a SLEB128 needs to be
     71 /// written to the data stream.
     72 void ObjectCodeEmitter::emitSLEB128Bytes(uint64_t Value) {
     73   BO->emitSLEB128Bytes(Value);
     74 }
     75 
     76 /// emitString - This callback is invoked when a String needs to be
     77 /// written to the data stream.
     78 void ObjectCodeEmitter::emitString(const std::string &String) {
     79   BO->emitString(String);
     80 }
     81 
     82 /// getCurrentPCValue - This returns the address that the next emitted byte
     83 /// will be output to.
     84 uintptr_t ObjectCodeEmitter::getCurrentPCValue() const {
     85   return BO->getCurrentPCOffset();
     86 }
     87 
     88 /// getCurrentPCOffset - Return the offset from the start of the emitted
     89 /// buffer that we are currently writing to.
     90 uintptr_t ObjectCodeEmitter::getCurrentPCOffset() const {
     91   return BO->getCurrentPCOffset();
     92 }
     93 
     94 /// addRelocation - Whenever a relocatable address is needed, it should be
     95 /// noted with this interface.
     96 void ObjectCodeEmitter::addRelocation(const MachineRelocation& relocation) {
     97   BO->addRelocation(relocation);
     98 }
     99 
    100 /// StartMachineBasicBlock - This should be called by the target when a new
    101 /// basic block is about to be emitted.  This way the MCE knows where the
    102 /// start of the block is, and can implement getMachineBasicBlockAddress.
    103 void ObjectCodeEmitter::StartMachineBasicBlock(MachineBasicBlock *MBB) {
    104   if (MBBLocations.size() <= (unsigned)MBB->getNumber())
    105     MBBLocations.resize((MBB->getNumber()+1)*2);
    106   MBBLocations[MBB->getNumber()] = getCurrentPCOffset();
    107 }
    108 
    109 /// getMachineBasicBlockAddress - Return the address of the specified
    110 /// MachineBasicBlock, only usable after the label for the MBB has been
    111 /// emitted.
    112 uintptr_t
    113 ObjectCodeEmitter::getMachineBasicBlockAddress(MachineBasicBlock *MBB) const {
    114   assert(MBBLocations.size() > (unsigned)MBB->getNumber() &&
    115          MBBLocations[MBB->getNumber()] && "MBB not emitted!");
    116   return MBBLocations[MBB->getNumber()];
    117 }
    118 
    119 /// getJumpTableEntryAddress - Return the address of the jump table with index
    120 /// 'Index' in the function that last called initJumpTableInfo.
    121 uintptr_t ObjectCodeEmitter::getJumpTableEntryAddress(unsigned Index) const {
    122   assert(JTLocations.size() > Index && "JT not emitted!");
    123   return JTLocations[Index];
    124 }
    125 
    126 /// getConstantPoolEntryAddress - Return the address of the 'Index' entry in
    127 /// the constant pool that was last emitted with the emitConstantPool method.
    128 uintptr_t ObjectCodeEmitter::getConstantPoolEntryAddress(unsigned Index) const {
    129   assert(CPLocations.size() > Index && "CP not emitted!");
    130   return CPLocations[Index];
    131 }
    132 
    133 /// getConstantPoolEntrySection - Return the section of the 'Index' entry in
    134 /// the constant pool that was last emitted with the emitConstantPool method.
    135 uintptr_t ObjectCodeEmitter::getConstantPoolEntrySection(unsigned Index) const {
    136   assert(CPSections.size() > Index && "CP not emitted!");
    137   return CPSections[Index];
    138 }
    139 
    140 } // end namespace llvm
    141 
    142