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
21 #include "llvm/Support/DataTypes.h"
26 class MachineBasicBlock;
27 class MachineCodeEmitter;
28 class MachineRelocation;
30 /// TargetJITInfo - Target specific information required by the Just-In-Time
34 virtual ~TargetJITInfo() {}
36 /// replaceMachineCodeForFunction - Make it so that calling the function
37 /// whose machine code is at OLD turns into a call to NEW, perhaps by
38 /// overwriting OLD with a branch to NEW. This is used for self-modifying
41 virtual void replaceMachineCodeForFunction(void *Old, void *New) = 0;
43 /// emitGlobalValueIndirectSym - Use the specified MachineCodeEmitter object
44 /// to emit an indirect symbol which contains the address of the specified
46 virtual void *emitGlobalValueIndirectSym(const GlobalValue* GV, void *ptr,
47 MachineCodeEmitter &MCE) {
48 assert(0 && "This target doesn't implement emitGlobalValueIndirectSym!");
52 /// emitFunctionStub - Use the specified MachineCodeEmitter object to emit a
53 /// small native function that simply calls the function at the specified
54 /// address. Return the address of the resultant function.
55 virtual void *emitFunctionStub(const Function* F, void *Fn,
56 MachineCodeEmitter &MCE) {
57 assert(0 && "This target doesn't implement emitFunctionStub!");
61 /// getPICJumpTableEntry - Returns the value of the jumptable entry for the
62 /// specific basic block.
63 virtual uintptr_t getPICJumpTableEntry(uintptr_t BB, uintptr_t JTBase) {
64 assert(0 && "This target doesn't implement getPICJumpTableEntry!");
68 /// LazyResolverFn - This typedef is used to represent the function that
69 /// unresolved call points should invoke. This is a target specific
70 /// function that knows how to walk the stack and find out which stub the
71 /// call is coming from.
72 typedef void (*LazyResolverFn)();
74 /// JITCompilerFn - This typedef is used to represent the JIT function that
75 /// lazily compiles the function corresponding to a stub. The JIT keeps
76 /// track of the mapping between stubs and LLVM Functions, the target
77 /// provides the ability to figure out the address of a stub that is called
78 /// by the LazyResolverFn.
79 typedef void* (*JITCompilerFn)(void *);
81 /// getLazyResolverFunction - This method is used to initialize the JIT,
82 /// giving the target the function that should be used to compile a
83 /// function, and giving the JIT the target function used to do the lazy
85 virtual LazyResolverFn getLazyResolverFunction(JITCompilerFn) {
86 assert(0 && "Not implemented for this target!");
90 /// relocate - Before the JIT can run a block of code that has been emitted,
91 /// it must rewrite the code to contain the actual addresses of any
92 /// referenced global symbols.
93 virtual void relocate(void *Function, MachineRelocation *MR,
94 unsigned NumRelocs, unsigned char* GOTBase) {
95 assert(NumRelocs == 0 && "This target does not have relocations!");
99 /// allocateThreadLocalMemory - Each target has its own way of
100 /// handling thread local variables. This method returns a value only
101 /// meaningful to the target.
102 virtual char* allocateThreadLocalMemory(size_t size) {
103 assert(0 && "This target does not implement thread local storage!");
107 /// needsGOT - Allows a target to specify that it would like the
108 // JIT to manage a GOT for it.
109 bool needsGOT() const { return useGOT; }
111 /// hasCustomConstantPool - Allows a target to specify that constant
112 /// pool address resolution is handled by the target.
113 virtual bool hasCustomConstantPool() const { return false; }
115 /// hasCustomJumpTables - Allows a target to specify that jumptables
116 /// are emitted by the target.
117 virtual bool hasCustomJumpTables() const { return false; }
119 /// allocateSeparateGVMemory - If true, globals should be placed in
120 /// separately allocated heap memory rather than in the same
121 /// code memory allocated by MachineCodeEmitter.
122 virtual bool allocateSeparateGVMemory() const { return false; }
126 } // End llvm namespace