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//===-- IntrinsicLowering.h - Intrinsic Function Lowering -------*- 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 defines the IntrinsicLowering interface. This interface allows
// addition of domain-specific or front-end specific intrinsics to LLVM without
// having to modify all of the code generators to support the new intrinsic.
// Later, as desired, targets can incrementally add support for particular
// intrinsic functions, as desired, to generate better code.
//
// If a code generator cannot handle or does not know about an intrinsic
// function, it will use the intrinsic lowering interface to change an intrinsic
// function name into a concrete function name which can be used to implement
// the functionality of the intrinsic. For example, llvm.memcpy can be
// implemented as a call to the math library 'memcpy' function if the target
// doesn't have hardware support for the intrinsic, or if it has not yet been
// implemented yet.
//
// Another use for this interface is the addition of domain-specific intrinsics.
// The default implementation of this interface would then lower the intrinsics
// to noop calls, allowing the direct execution of programs with instrumentation
// or other hooks placed in them. When a specific tool or flag is used, a
// different implementation of these interfaces may be used, which activates the
// intrinsics in some way.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_INTRINSICLOWERING_H
#define LLVM_CODEGEN_INTRINSICLOWERING_H
#include "llvm/Intrinsics.h"
namespace llvm {
class CallInst;
class Module;
class IntrinsicLowering {
public:
virtual ~IntrinsicLowering() {}
/// AddPrototypes - This method, if called, causes all of the prototypes
/// that might be needed by an intrinsic lowering implementation to be
/// inserted into the module specified.
virtual void AddPrototypes(Module &M) = 0;
/// LowerIntrinsicCall - This method returns the LLVM function which should
/// be used to implement the specified intrinsic function call. If an
/// intrinsic function must be implemented by the code generator (such as
/// va_start), this function should print a message and abort.
///
/// Otherwise, if an intrinsic function call can be lowered, the code to
/// implement it (often a call to a non-intrinsic function) is inserted
/// _after_ the call instruction and the call is deleted. The caller must
/// be capable of handling this kind of change.
///
virtual void LowerIntrinsicCall(CallInst *CI) = 0;
};
/// DefaultIntrinsicLower - This is the default intrinsic lowering pass which
/// is used if no other one is specified. Custom intrinsic lowering
/// implementations should pass any unhandled intrinsics to this
/// implementation to allow for future extensibility.
struct DefaultIntrinsicLowering : public IntrinsicLowering {
virtual void AddPrototypes(Module &M);
virtual void LowerIntrinsicCall(CallInst *CI);
};
}
#endif