LLVM  3.7.0
IntrinsicInst.cpp
Go to the documentation of this file.
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"
28 using namespace llvm;
29 
30 //===----------------------------------------------------------------------===//
31 /// DbgInfoIntrinsic - This is the common base class for debug info intrinsics
32 ///
33 
34 static 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 
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 static 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 
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 
77 const Value *DbgValueInst::getValue() const {
78  return const_cast<DbgValueInst *>(this)->getValue();
79 }
80 
static Value * getValueImpl(Value *Op)
This file contains the declarations for metadata subclasses.
static Value * StripCast(Value *C)
ConstantExpr - a constant value that is initialized with an expression using other constant values...
Definition: Constants.h:852
static Value * CastOperand(Value *C)
DbgInfoIntrinsic - This is the common base class for debug info intrinsics.
This file contains the declarations for the subclasses of Constant, which represent the different fla...
Value * getArgOperand(unsigned i) const
getArgOperand/setArgOperand - Return/set the i-th call argument.
LLVM_ATTRIBUTE_UNUSED_RESULT std::enable_if< !is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:285
DbgValueInst - This represents the llvm.dbg.value instruction.
LLVM Value Representation.
Definition: Value.h:69
Value * getAddress() const
DbgDeclareInst - This represents the llvm.dbg.declare instruction.
const Value * getValue() const
DbgValueInst - This represents the llvm.dbg.value instruction.