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
25 class FunctionPassManager;
26 class MachineBasicBlock;
27 class MachineCodeEmitter;
28 class MachineRelocation;
30 /// TargetJITInfo - Target specific information required by the Just-In-Time
34 virtual ~TargetJITInfo() {}
36 /// addPassesToJITCompile - Add passes to the specified pass manager to
37 /// implement a fast code generator for this target.
39 virtual void addPassesToJITCompile(FunctionPassManager &PM) = 0;
41 /// replaceMachineCodeForFunction - Make it so that calling the function
42 /// whose machine code is at OLD turns into a call to NEW, perhaps by
43 /// overwriting OLD with a branch to NEW. This is used for self-modifying
46 virtual void replaceMachineCodeForFunction(void *Old, void *New) = 0;
48 /// emitFunctionStub - Use the specified MachineCodeEmitter object to emit a
49 /// small native function that simply calls the function at the specified
50 /// address. Return the address of the resultant function.
51 virtual void *emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
52 assert(0 && "This target doesn't implement emitFunctionStub!");
56 /// LazyResolverFn - This typedef is used to represent the function that
57 /// unresolved call points should invoke. This is a target specific
58 /// function that knows how to walk the stack and find out which stub the
59 /// call is coming from.
60 typedef void (*LazyResolverFn)();
62 /// JITCompilerFn - This typedef is used to represent the JIT function that
63 /// lazily compiles the function corresponding to a stub. The JIT keeps
64 /// track of the mapping between stubs and LLVM Functions, the target
65 /// provides the ability to figure out the address of a stub that is called
66 /// by the LazyResolverFn.
67 typedef void* (*JITCompilerFn)(void *);
69 /// getLazyResolverFunction - This method is used to initialize the JIT,
70 /// giving the target the function that should be used to compile a
71 /// function, and giving the JIT the target function used to do the lazy
73 virtual LazyResolverFn getLazyResolverFunction(JITCompilerFn) {
74 assert(0 && "Not implemented for this target!");
78 /// relocate - Before the JIT can run a block of code that has been emitted,
79 /// it must rewrite the code to contain the actual addresses of any
80 /// referenced global symbols.
81 virtual void relocate(void *Function, MachineRelocation *MR,
82 unsigned NumRelocs, unsigned char* GOTBase) {
83 assert(NumRelocs == 0 && "This target does not have relocations!");
86 /// resolveBBRefs - Resolve branches to BasicBlocks for the JIT emitted
88 virtual void resolveBBRefs(MachineCodeEmitter &MCE) {}
90 /// addBBRef - Add a BasicBlock reference to be resolved after the function
92 void addBBRef(MachineBasicBlock *BB, intptr_t PC) {
93 BBRefs.push_back(std::make_pair(BB, PC));
96 /// needsGOT - Allows a target to specify that it would like the
97 // JIT to manage a GOT for it.
98 bool needsGOT() const { return useGOT; }
103 // Tracks which instruction references which BasicBlock
104 std::vector<std::pair<MachineBasicBlock*, intptr_t> > BBRefs;
107 } // End llvm namespace