X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FCodeGen%2FMachineCodeEmitter.h;h=7abb49a219efe8104c43e1b93d6f8785e1a45fa9;hb=5eb195153950bc7ebfc30649494a78b2096b5ef8;hp=f0e5e3f2cb275b56dc205681a48294ac99f46609;hpb=ffc2d6f48544b24d3ac31f486d20c7073cb0b35f;p=oota-llvm.git diff --git a/include/llvm/CodeGen/MachineCodeEmitter.h b/include/llvm/CodeGen/MachineCodeEmitter.h index f0e5e3f2cb2..7abb49a219e 100644 --- a/include/llvm/CodeGen/MachineCodeEmitter.h +++ b/include/llvm/CodeGen/MachineCodeEmitter.h @@ -1,54 +1,332 @@ //===-- llvm/CodeGen/MachineCodeEmitter.h - Code emission -------*- C++ -*-===// // +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// // This file defines an abstract interface that is used by the machine code // emission framework to output the code. This allows machine code emission to -// be seperated from concerns such as resolution of call targets, and where the +// be separated from concerns such as resolution of call targets, and where the // machine code will be written (memory or disk, f.e.). // //===----------------------------------------------------------------------===// -#ifndef LLVM_CODEGEN_MACHINE_CODE_EMITTER_H -#define LLVM_CODEGEN_MACHINE_CODE_EMITTER_H +#ifndef LLVM_CODEGEN_MACHINECODEEMITTER_H +#define LLVM_CODEGEN_MACHINECODEEMITTER_H + +#include "llvm/System/DataTypes.h" +#include "llvm/Support/DebugLoc.h" + +namespace llvm { -class MachineFunction; class MachineBasicBlock; +class MachineConstantPool; +class MachineJumpTableInfo; +class MachineFunction; +class MachineModuleInfo; +class MachineRelocation; class Value; +class GlobalValue; +class Function; +class MCSymbol; + +/// MachineCodeEmitter - This class defines two sorts of methods: those for +/// emitting the actual bytes of machine code, and those for emitting auxillary +/// structures, such as jump tables, relocations, etc. +/// +/// Emission of machine code is complicated by the fact that we don't (in +/// general) know the size of the machine code that we're about to emit before +/// we emit it. As such, we preallocate a certain amount of memory, and set the +/// BufferBegin/BufferEnd pointers to the start and end of the buffer. As we +/// emit machine instructions, we advance the CurBufferPtr to indicate the +/// location of the next byte to emit. In the case of a buffer overflow (we +/// need to emit more machine code than we have allocated space for), the +/// CurBufferPtr will saturate to BufferEnd and ignore stores. Once the entire +/// function has been emitted, the overflow condition is checked, and if it has +/// occurred, more memory is allocated, and we reemit the code into it. +/// +class MachineCodeEmitter { +protected: + /// BufferBegin/BufferEnd - Pointers to the start and end of the memory + /// allocated for this code buffer. + uint8_t *BufferBegin, *BufferEnd; + /// CurBufferPtr - Pointer to the next byte of memory to fill when emitting + /// code. This is guranteed to be in the range [BufferBegin,BufferEnd]. If + /// this pointer is at BufferEnd, it will never move due to code emission, and + /// all code emission requests will be ignored (this is the buffer overflow + /// condition). + uint8_t *CurBufferPtr; -struct MachineCodeEmitter { +public: virtual ~MachineCodeEmitter() {} /// startFunction - This callback is invoked when the specified function is - /// about to be code generated. - /// - virtual void startFunction(MachineFunction &F) {} - - /// finishFunction - This callback is invoked when the specified function has - /// finished code generation. + /// about to be code generated. This initializes the BufferBegin/End/Ptr + /// fields. /// - virtual void finishFunction(MachineFunction &F) {} + virtual void startFunction(MachineFunction &F) = 0; - /// startBasicBlock - This callback is invoked when a new basic block is about - /// to be emitted. + /// finishFunction - This callback is invoked when the specified function has + /// finished code generation. If a buffer overflow has occurred, this method + /// returns true (the callee is required to try again), otherwise it returns + /// false. /// - virtual void startBasicBlock(MachineBasicBlock &BB) {} + virtual bool finishFunction(MachineFunction &F) = 0; /// emitByte - This callback is invoked when a byte needs to be written to the /// output stream. /// - virtual void emitByte(unsigned char B) {} + void emitByte(uint8_t B) { + if (CurBufferPtr != BufferEnd) + *CurBufferPtr++ = B; + } - /// emitPCRelativeDisp - This callback is invoked when we need to write out a - /// PC relative displacement for the specified Value*. This is used for call - /// and jump instructions typically. + /// emitWordLE - This callback is invoked when a 32-bit word needs to be + /// written to the output stream in little-endian format. /// - virtual void emitPCRelativeDisp(Value *V) {} + void emitWordLE(uint32_t W) { + if (4 <= BufferEnd-CurBufferPtr) { + emitWordLEInto(CurBufferPtr, W); + } else { + CurBufferPtr = BufferEnd; + } + } + /// emitWordLEInto - This callback is invoked when a 32-bit word needs to be + /// written to an arbitrary buffer in little-endian format. Buf must have at + /// least 4 bytes of available space. + /// + static void emitWordLEInto(uint8_t *&Buf, uint32_t W) { + *Buf++ = (uint8_t)(W >> 0); + *Buf++ = (uint8_t)(W >> 8); + *Buf++ = (uint8_t)(W >> 16); + *Buf++ = (uint8_t)(W >> 24); + } + + /// emitWordBE - This callback is invoked when a 32-bit word needs to be + /// written to the output stream in big-endian format. + /// + void emitWordBE(uint32_t W) { + if (4 <= BufferEnd-CurBufferPtr) { + *CurBufferPtr++ = (uint8_t)(W >> 24); + *CurBufferPtr++ = (uint8_t)(W >> 16); + *CurBufferPtr++ = (uint8_t)(W >> 8); + *CurBufferPtr++ = (uint8_t)(W >> 0); + } else { + CurBufferPtr = BufferEnd; + } + } - /// createDebugMachineCodeEmitter - Return a dynamically allocated machine - /// code emitter, which just prints the opcodes and fields out the cout. This - /// can be used for debugging users of the MachineCodeEmitter interface. + /// emitDWordLE - This callback is invoked when a 64-bit word needs to be + /// written to the output stream in little-endian format. /// - static MachineCodeEmitter *createDebugMachineCodeEmitter(); + void emitDWordLE(uint64_t W) { + if (8 <= BufferEnd-CurBufferPtr) { + *CurBufferPtr++ = (uint8_t)(W >> 0); + *CurBufferPtr++ = (uint8_t)(W >> 8); + *CurBufferPtr++ = (uint8_t)(W >> 16); + *CurBufferPtr++ = (uint8_t)(W >> 24); + *CurBufferPtr++ = (uint8_t)(W >> 32); + *CurBufferPtr++ = (uint8_t)(W >> 40); + *CurBufferPtr++ = (uint8_t)(W >> 48); + *CurBufferPtr++ = (uint8_t)(W >> 56); + } else { + CurBufferPtr = BufferEnd; + } + } + + /// emitDWordBE - This callback is invoked when a 64-bit word needs to be + /// written to the output stream in big-endian format. + /// + void emitDWordBE(uint64_t W) { + if (8 <= BufferEnd-CurBufferPtr) { + *CurBufferPtr++ = (uint8_t)(W >> 56); + *CurBufferPtr++ = (uint8_t)(W >> 48); + *CurBufferPtr++ = (uint8_t)(W >> 40); + *CurBufferPtr++ = (uint8_t)(W >> 32); + *CurBufferPtr++ = (uint8_t)(W >> 24); + *CurBufferPtr++ = (uint8_t)(W >> 16); + *CurBufferPtr++ = (uint8_t)(W >> 8); + *CurBufferPtr++ = (uint8_t)(W >> 0); + } else { + CurBufferPtr = BufferEnd; + } + } + + /// emitAlignment - Move the CurBufferPtr pointer up to the specified + /// alignment (saturated to BufferEnd of course). + void emitAlignment(unsigned Alignment) { + if (Alignment == 0) Alignment = 1; + + if(Alignment <= (uintptr_t)(BufferEnd-CurBufferPtr)) { + // Move the current buffer ptr up to the specified alignment. + CurBufferPtr = + (uint8_t*)(((uintptr_t)CurBufferPtr+Alignment-1) & + ~(uintptr_t)(Alignment-1)); + } else { + CurBufferPtr = BufferEnd; + } + } + + + /// emitULEB128Bytes - This callback is invoked when a ULEB128 needs to be + /// written to the output stream. + void emitULEB128Bytes(uint64_t Value) { + do { + uint8_t Byte = Value & 0x7f; + Value >>= 7; + if (Value) Byte |= 0x80; + emitByte(Byte); + } while (Value); + } + + /// emitSLEB128Bytes - This callback is invoked when a SLEB128 needs to be + /// written to the output stream. + void emitSLEB128Bytes(uint64_t Value) { + uint64_t Sign = Value >> (8 * sizeof(Value) - 1); + bool IsMore; + + do { + uint8_t Byte = Value & 0x7f; + Value >>= 7; + IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0; + if (IsMore) Byte |= 0x80; + emitByte(Byte); + } while (IsMore); + } + + /// emitString - This callback is invoked when a String needs to be + /// written to the output stream. + void emitString(const std::string &String) { + for (unsigned i = 0, N = static_cast(String.size()); + i < N; ++i) { + uint8_t C = String[i]; + emitByte(C); + } + emitByte(0); + } + + /// emitInt32 - Emit a int32 directive. + void emitInt32(int32_t Value) { + if (4 <= BufferEnd-CurBufferPtr) { + *((uint32_t*)CurBufferPtr) = Value; + CurBufferPtr += 4; + } else { + CurBufferPtr = BufferEnd; + } + } + + /// emitInt64 - Emit a int64 directive. + void emitInt64(uint64_t Value) { + if (8 <= BufferEnd-CurBufferPtr) { + *((uint64_t*)CurBufferPtr) = Value; + CurBufferPtr += 8; + } else { + CurBufferPtr = BufferEnd; + } + } + + /// emitInt32At - Emit the Int32 Value in Addr. + void emitInt32At(uintptr_t *Addr, uintptr_t Value) { + if (Addr >= (uintptr_t*)BufferBegin && Addr < (uintptr_t*)BufferEnd) + (*(uint32_t*)Addr) = (uint32_t)Value; + } + + /// emitInt64At - Emit the Int64 Value in Addr. + void emitInt64At(uintptr_t *Addr, uintptr_t Value) { + if (Addr >= (uintptr_t*)BufferBegin && Addr < (uintptr_t*)BufferEnd) + (*(uint64_t*)Addr) = (uint64_t)Value; + } + + /// processDebugLoc - Records debug location information about a + /// MachineInstruction. This is called before emitting any bytes associated + /// with the instruction. Even if successive instructions have the same debug + /// location, this method will be called for each one. + virtual void processDebugLoc(DebugLoc DL, bool BeforePrintintInsn) {} + + /// emitLabel - Emits a label + virtual void emitLabel(MCSymbol *Label) = 0; + + /// allocateSpace - Allocate a block of space in the current output buffer, + /// returning null (and setting conditions to indicate buffer overflow) on + /// failure. Alignment is the alignment in bytes of the buffer desired. + virtual void *allocateSpace(uintptr_t Size, unsigned Alignment) { + emitAlignment(Alignment); + void *Result; + + // Check for buffer overflow. + if (Size >= (uintptr_t)(BufferEnd-CurBufferPtr)) { + CurBufferPtr = BufferEnd; + Result = 0; + } else { + // Allocate the space. + Result = CurBufferPtr; + CurBufferPtr += Size; + } + + return Result; + } + + /// StartMachineBasicBlock - This should be called by the target when a new + /// basic block is about to be emitted. This way the MCE knows where the + /// start of the block is, and can implement getMachineBasicBlockAddress. + virtual void StartMachineBasicBlock(MachineBasicBlock *MBB) = 0; + + /// getCurrentPCValue - This returns the address that the next emitted byte + /// will be output to. + /// + virtual uintptr_t getCurrentPCValue() const { + return (uintptr_t)CurBufferPtr; + } + + /// getCurrentPCOffset - Return the offset from the start of the emitted + /// buffer that we are currently writing to. + virtual uintptr_t getCurrentPCOffset() const { + return CurBufferPtr-BufferBegin; + } + + /// earlyResolveAddresses - True if the code emitter can use symbol addresses + /// during code emission time. The JIT is capable of doing this because it + /// creates jump tables or constant pools in memory on the fly while the + /// object code emitters rely on a linker to have real addresses and should + /// use relocations instead. + virtual bool earlyResolveAddresses() const = 0; + + /// addRelocation - Whenever a relocatable address is needed, it should be + /// noted with this interface. + virtual void addRelocation(const MachineRelocation &MR) = 0; + + /// FIXME: These should all be handled with relocations! + + /// getConstantPoolEntryAddress - Return the address of the 'Index' entry in + /// the constant pool that was last emitted with the emitConstantPool method. + /// + virtual uintptr_t getConstantPoolEntryAddress(unsigned Index) const = 0; + + /// getJumpTableEntryAddress - Return the address of the jump table with index + /// 'Index' in the function that last called initJumpTableInfo. + /// + virtual uintptr_t getJumpTableEntryAddress(unsigned Index) const = 0; + + /// getMachineBasicBlockAddress - Return the address of the specified + /// MachineBasicBlock, only usable after the label for the MBB has been + /// emitted. + /// + virtual uintptr_t getMachineBasicBlockAddress(MachineBasicBlock *MBB) const= 0; + + /// getLabelAddress - Return the address of the specified Label, only usable + /// after the LabelID has been emitted. + /// + virtual uintptr_t getLabelAddress(MCSymbol *Label) const = 0; + + /// Specifies the MachineModuleInfo object. This is used for exception handling + /// purposes. + virtual void setModuleInfo(MachineModuleInfo* Info) = 0; }; +} // End llvm namespace + #endif