1 //===- Target/TargetJITInfo.h - Target Information for JIT ------*- 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 exposes an abstract interface used by the Just-In-Time code
11 // generator to perform target-specific activities, such as emitting stubs. If
12 // a TargetMachine supports JIT code generation, it should provide one of these
13 // objects through the getJITInfo() method.
15 //===----------------------------------------------------------------------===//
17 #ifndef LLVM_TARGET_TARGETJITINFO_H
18 #define LLVM_TARGET_TARGETJITINFO_H
24 class FunctionPassManager;
25 class MachineCodeEmitter;
26 class MachineRelocation;
28 /// TargetJITInfo - Target specific information required by the Just-In-Time
32 virtual ~TargetJITInfo() {}
34 /// addPassesToJITCompile - Add passes to the specified pass manager to
35 /// implement a fast code generator for this target.
37 virtual void addPassesToJITCompile(FunctionPassManager &PM) = 0;
39 /// replaceMachineCodeForFunction - Make it so that calling the function
40 /// whose machine code is at OLD turns into a call to NEW, perhaps by
41 /// overwriting OLD with a branch to NEW. This is used for self-modifying
44 virtual void replaceMachineCodeForFunction(void *Old, void *New) = 0;
46 /// emitFunctionStub - Use the specified MachineCodeEmitter object to emit a
47 /// small native function that simply calls the function at the specified
48 /// address. Return the address of the resultant function.
49 virtual void *emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
50 assert(0 && "This target doesn't implement emitFunctionStub!");
54 /// LazyResolverFn - This typedef is used to represent the function that
55 /// unresolved call points should invoke. This is a target specific
56 /// function that knows how to walk the stack and find out which stub the
57 /// call is coming from.
58 typedef void (*LazyResolverFn)();
60 /// JITCompilerFn - This typedef is used to represent the JIT function that
61 /// lazily compiles the function corresponding to a stub. The JIT keeps
62 /// track of the mapping between stubs and LLVM Functions, the target
63 /// provides the ability to figure out the address of a stub that is called
64 /// by the LazyResolverFn.
65 typedef void* (*JITCompilerFn)(void *);
67 /// getLazyResolverFunction - This method is used to initialize the JIT,
68 /// giving the target the function that should be used to compile a
69 /// function, and giving the JIT the target function used to do the lazy
71 virtual LazyResolverFn getLazyResolverFunction(JITCompilerFn) {
72 assert(0 && "Not implemented for this target!");
76 /// relocate - Before the JIT can run a block of code that has been emitted,
77 /// it must rewrite the code to contain the actual addresses of any
78 /// referenced global symbols.
79 virtual void relocate(void *Function, MachineRelocation *MR,
81 assert(NumRelocs == 0 && "This target does not have relocations!");
84 } // End llvm namespace