1 //===-- llvm/CodeGen/MachineCodeEmitter.h - Code emission -------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines an abstract interface that is used by the machine code
11 // emission framework to output the code. This allows machine code emission to
12 // be separated from concerns such as resolution of call targets, and where the
13 // machine code will be written (memory or disk, f.e.).
15 //===----------------------------------------------------------------------===//
17 #ifndef LLVM_CODEGEN_MACHINECODEEMITTER_H
18 #define LLVM_CODEGEN_MACHINECODEEMITTER_H
21 #include "llvm/Support/DataTypes.h"
25 class MachineFunction;
26 class MachineBasicBlock;
27 class MachineConstantPool;
32 struct MachineCodeEmitter {
33 virtual ~MachineCodeEmitter() {}
35 /// startFunction - This callback is invoked when the specified function is
36 /// about to be code generated.
38 virtual void startFunction(MachineFunction &F) {}
40 /// finishFunction - This callback is invoked when the specified function has
41 /// finished code generation.
43 virtual void finishFunction(MachineFunction &F) {}
45 /// emitConstantPool - This callback is invoked to output the constant pool
47 virtual void emitConstantPool(MachineConstantPool *MCP) {}
49 /// startFunctionStub - This callback is invoked when the JIT needs the
50 /// address of a function that has not been code generated yet. The StubSize
51 /// specifies the total size required by the stub. Stubs are not allowed to
52 /// have constant pools, the can only use the other emit* methods.
54 virtual void startFunctionStub(const Function &F, unsigned StubSize) {}
56 /// finishFunctionStub - This callback is invoked to terminate a function
59 virtual void *finishFunctionStub(const Function &F) { return 0; }
61 /// emitByte - This callback is invoked when a byte needs to be written to the
64 virtual void emitByte(unsigned char B) {}
66 /// emitWordAt - This callback is invoked when a word needs to be written to
67 /// the output stream at a different position than the current PC (for
68 /// instance, when performing relocations).
70 virtual void emitWordAt(unsigned W, unsigned *Ptr) {}
72 /// emitWord - This callback is invoked when a word needs to be written to the
75 virtual void emitWord(unsigned W) = 0;
77 /// getGlobalValueAddress - This method is used to get the address of the
78 /// specified global value. In some cases, however, the address may not yet
79 /// be known at the point that the method is called (for example, getting the
80 /// address of a function which has not yet been code generated). If this is
81 /// the case, the function returns zero, and the callee has to be able to
82 /// handle the situation.
84 virtual uint64_t getGlobalValueAddress(GlobalValue *V) = 0;
85 virtual uint64_t getGlobalValueAddress(const std::string &Name) = 0;
87 // getConstantPoolEntryAddress - Return the address of the 'Index' entry in
88 // the constant pool that was last emitted with the 'emitConstantPool' method.
90 virtual uint64_t getConstantPoolEntryAddress(unsigned Index) = 0;
92 // getCurrentPCValue - This returns the address that the next emitted byte
95 virtual uint64_t getCurrentPCValue() = 0;
97 // forceCompilationOf - Force the compilation of the specified function, and
98 // return its address, because we REALLY need the address now.
100 // FIXME: This is JIT specific!
102 virtual uint64_t forceCompilationOf(Function *F) = 0;
104 /// createDebugEmitter - Return a dynamically allocated machine
105 /// code emitter, which just prints the opcodes and fields out the cout. This
106 /// can be used for debugging users of the MachineCodeEmitter interface.
108 static MachineCodeEmitter *createDebugEmitter();
110 /// createFilePrinterEmitter - Return a dynamically allocated
111 /// machine code emitter, which prints binary code to a file. This
112 /// can be used for debugging users of the MachineCodeEmitter interface.
114 static MachineCodeEmitter *createFilePrinterEmitter(MachineCodeEmitter&);
117 } // End llvm namespace