IntrinsicInst.cpp revision 36b56886974eae4f9c5ebc96befd3e7bfe5de338 
1//===-- InstrinsicInst.cpp - Intrinsic Instruction Wrappers ---------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements methods that make it really easy to deal with intrinsic
11// functions.
12//
13// All intrinsic function calls are instances of the call instruction, so these
14// are all subclasses of the CallInst class.  Note that none of these classes
15// has state or virtual methods, which is an important part of this gross/neat
16// hack working.
17//
18// In some cases, arguments to intrinsics need to be generic and are defined as
19// type pointer to empty struct { }*.  To access the real item of interest the
20// cast instruction needs to be stripped away.
21//
22//===----------------------------------------------------------------------===//
23
24#include "llvm/IR/IntrinsicInst.h"
25#include "llvm/IR/Constants.h"
26#include "llvm/IR/GlobalVariable.h"
27#include "llvm/IR/Metadata.h"
28using namespace llvm;
29
30//===----------------------------------------------------------------------===//
31/// DbgInfoIntrinsic - This is the common base class for debug info intrinsics
32///
33
34static Value *CastOperand(Value *C) {
35  if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
36    if (CE->isCast())
37      return CE->getOperand(0);
38  return NULL;
39}
40
41Value *DbgInfoIntrinsic::StripCast(Value *C) {
42  if (Value *CO = CastOperand(C)) {
43    C = StripCast(CO);
44  } else if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
45    if (GV->hasInitializer())
46      if (Value *CO = CastOperand(GV->getInitializer()))
47        C = StripCast(CO);
48  }
49  return dyn_cast<GlobalVariable>(C);
50}
51
52//===----------------------------------------------------------------------===//
53/// DbgDeclareInst - This represents the llvm.dbg.declare instruction.
54///
55
56Value *DbgDeclareInst::getAddress() const {
57  if (MDNode* MD = cast_or_null<MDNode>(getArgOperand(0)))
58    return MD->getOperand(0);
59  else
60    return NULL;
61}
62
63//===----------------------------------------------------------------------===//
64/// DbgValueInst - This represents the llvm.dbg.value instruction.
65///
66
67const Value *DbgValueInst::getValue() const {
68  return cast<MDNode>(getArgOperand(0))->getOperand(0);
69}
70
71Value *DbgValueInst::getValue() {
72  return cast<MDNode>(getArgOperand(0))->getOperand(0);
73}
74