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//===- Target/TargetJITInfo.h - Target Information for JIT ------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file exposes an abstract interface used by the Just-In-Time code
// generator to perform target-specific activities, such as emitting stubs. If
// a TargetMachine supports JIT code generation, it should provide one of these
// objects through the getJITInfo() method.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_TARGETJITINFO_H
#define LLVM_TARGET_TARGETJITINFO_H
#include <cassert>
#include <vector>
namespace llvm {
class Function;
class FunctionPassManager;
class MachineBasicBlock;
class MachineCodeEmitter;
class MachineRelocation;
/// TargetJITInfo - Target specific information required by the Just-In-Time
/// code generator.
class TargetJITInfo {
public:
virtual ~TargetJITInfo() {}
/// replaceMachineCodeForFunction - Make it so that calling the function
/// whose machine code is at OLD turns into a call to NEW, perhaps by
/// overwriting OLD with a branch to NEW. This is used for self-modifying
/// code.
///
virtual void replaceMachineCodeForFunction(void *Old, void *New) = 0;
/// emitFunctionStub - Use the specified MachineCodeEmitter object to emit a
/// small native function that simply calls the function at the specified
/// address. Return the address of the resultant function.
virtual void *emitFunctionStub(void *Fn, MachineCodeEmitter &MCE) {
assert(0 && "This target doesn't implement emitFunctionStub!");
return 0;
}
/// LazyResolverFn - This typedef is used to represent the function that
/// unresolved call points should invoke. This is a target specific
/// function that knows how to walk the stack and find out which stub the
/// call is coming from.
typedef void (*LazyResolverFn)();
/// JITCompilerFn - This typedef is used to represent the JIT function that
/// lazily compiles the function corresponding to a stub. The JIT keeps
/// track of the mapping between stubs and LLVM Functions, the target
/// provides the ability to figure out the address of a stub that is called
/// by the LazyResolverFn.
typedef void* (*JITCompilerFn)(void *);
/// getLazyResolverFunction - This method is used to initialize the JIT,
/// giving the target the function that should be used to compile a
/// function, and giving the JIT the target function used to do the lazy
/// resolving.
virtual LazyResolverFn getLazyResolverFunction(JITCompilerFn) {
assert(0 && "Not implemented for this target!");
return 0;
}
/// relocate - Before the JIT can run a block of code that has been emitted,
/// it must rewrite the code to contain the actual addresses of any
/// referenced global symbols.
virtual void relocate(void *Function, MachineRelocation *MR,
unsigned NumRelocs, unsigned char* GOTBase) {
assert(NumRelocs == 0 && "This target does not have relocations!");
}
/// needsGOT - Allows a target to specify that it would like the
// JIT to manage a GOT for it.
bool needsGOT() const { return useGOT; }
protected:
bool useGOT;
};
} // End llvm namespace
#endif
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