+#ifndef LLVM_CODEGEN_MACHINECODEEMITTER_H
+#define LLVM_CODEGEN_MACHINECODEEMITTER_H
+
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/DebugLoc.h"
+#include <string>
+
+namespace llvm {
+
+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 auxiliary
+/// 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 {
+ virtual void anchor();
+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 guaranteed 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;
+
+public:
+ virtual ~MachineCodeEmitter() {}
+
+ /// startFunction - This callback is invoked when the specified function is
+ /// about to be code generated. This initializes the BufferBegin/End/Ptr
+ /// fields.
+ ///
+ virtual void startFunction(MachineFunction &F) = 0;
+
+ /// 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 bool finishFunction(MachineFunction &F) = 0;
+
+ /// emitByte - This callback is invoked when a byte needs to be written to the
+ /// output stream.
+ ///
+ void emitByte(uint8_t B) {
+ if (CurBufferPtr != BufferEnd)
+ *CurBufferPtr++ = B;
+ }
+
+ /// emitWordLE - This callback is invoked when a 32-bit word needs to be
+ /// written to the output stream in little-endian format.
+ ///
+ 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;
+ }
+ }
+
+ /// emitDWordLE - This callback is invoked when a 64-bit word needs to be
+ /// written to the output stream in little-endian format.
+ ///
+ 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<unsigned>(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) {}