1 //===- Target/TargetJITInfo.h - Target Information for JIT ------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // 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
22 #include "llvm/Support/DataTypes.h"
26 class FunctionPassManager;
27 class MachineBasicBlock;
28 class MachineCodeEmitter;
29 class MachineRelocation;
31 /// TargetJITInfo - Target specific information required by the Just-In-Time
35 virtual ~TargetJITInfo() {}
37 /// replaceMachineCodeForFunction - Make it so that calling the function
38 /// whose machine code is at OLD turns into a call to NEW, perhaps by
39 /// overwriting OLD with a branch to NEW. This is used for self-modifying
42 virtual void replaceMachineCodeForFunction(void *Old, void *New) = 0;
44 /// emitGlobalValueLazyPtr - Use the specified MachineCodeEmitter object to
45 /// emit a lazy pointer which contains the address of the specified GV.
46 virtual void *emitGlobalValueLazyPtr(void *GV, MachineCodeEmitter &MCE) {
47 assert(0 && "This target doesn't implement emitGlobalValueLazyPtr!");
51 /// emitFunctionStub - Use the specified MachineCodeEmitter object to emit a
52 /// small native function that simply calls the function at the specified
53 /// address. Return the address of the resultant function.
54 virtual void *emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
55 assert(0 && "This target doesn't implement emitFunctionStub!");
59 /// getPICJumpTableEntry - Returns the value of the jumptable entry for the
60 /// specific basic block.
61 virtual intptr_t getPICJumpTableEntry(intptr_t BB, intptr_t JTBase) {
62 assert(0 && "This target doesn't implement getPICJumpTableEntry!");
66 /// LazyResolverFn - This typedef is used to represent the function that
67 /// unresolved call points should invoke. This is a target specific
68 /// function that knows how to walk the stack and find out which stub the
69 /// call is coming from.
70 typedef void (*LazyResolverFn)();
72 /// JITCompilerFn - This typedef is used to represent the JIT function that
73 /// lazily compiles the function corresponding to a stub. The JIT keeps
74 /// track of the mapping between stubs and LLVM Functions, the target
75 /// provides the ability to figure out the address of a stub that is called
76 /// by the LazyResolverFn.
77 typedef void* (*JITCompilerFn)(void *);
79 /// getLazyResolverFunction - This method is used to initialize the JIT,
80 /// giving the target the function that should be used to compile a
81 /// function, and giving the JIT the target function used to do the lazy
83 virtual LazyResolverFn getLazyResolverFunction(JITCompilerFn) {
84 assert(0 && "Not implemented for this target!");
88 /// relocate - Before the JIT can run a block of code that has been emitted,
89 /// it must rewrite the code to contain the actual addresses of any
90 /// referenced global symbols.
91 virtual void relocate(void *Function, MachineRelocation *MR,
92 unsigned NumRelocs, unsigned char* GOTBase) {
93 assert(NumRelocs == 0 && "This target does not have relocations!");
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 } // End llvm namespace