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 nullptr;
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
52static Value *getValueImpl(Value *Op) {
53  auto *MD = cast<MetadataAsValue>(Op)->getMetadata();
54  if (auto *V = dyn_cast<ValueAsMetadata>(MD))
55    return V->getValue();
56
57  // When the value goes to null, it gets replaced by an empty MDNode.
58  assert(!cast<MDNode>(MD)->getNumOperands() && "Expected an empty MDNode");
59  return nullptr;
60}
61
62//===----------------------------------------------------------------------===//
63/// DbgDeclareInst - This represents the llvm.dbg.declare instruction.
64///
65
66Value *DbgDeclareInst::getAddress() const {
67  if (!getArgOperand(0))
68    return nullptr;
69
70  return getValueImpl(getArgOperand(0));
71}
72
73//===----------------------------------------------------------------------===//
74/// DbgValueInst - This represents the llvm.dbg.value instruction.
75///
76
77const Value *DbgValueInst::getValue() const {
78  return const_cast<DbgValueInst *>(this)->getValue();
79}
80
81Value *DbgValueInst::getValue() { return getValueImpl(getArgOperand(0)); }
82