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 #include "llvm/IR/Module.h"
29 #include "llvm/Support/raw_ostream.h"
30 using namespace llvm;
31 
32 //===----------------------------------------------------------------------===//
33 /// DbgInfoIntrinsic - This is the common base class for debug info intrinsics
34 ///
35 
36 Value *DbgInfoIntrinsic::getVariableLocation(bool AllowNullOp) const {
37   Value *Op = getArgOperand(0);
38   if (AllowNullOp && !Op)
39     return nullptr;
40 
41   auto *MD = cast<MetadataAsValue>(Op)->getMetadata();
42   if (auto *V = dyn_cast<ValueAsMetadata>(MD))
43     return V->getValue();
44 
45   // When the value goes to null, it gets replaced by an empty MDNode.
46   assert(!cast<MDNode>(MD)->getNumOperands() && "Expected an empty MDNode");
47   return nullptr;
48 }
49 
50 int llvm::Intrinsic::lookupLLVMIntrinsicByName(ArrayRef<const char *> NameTable,
51                                                StringRef Name) {
52   assert(Name.startswith("llvm."));
53 
54   // Do successive binary searches of the dotted name components. For
55   // "llvm.gc.experimental.statepoint.p1i8.p1i32", we will find the range of
56   // intrinsics starting with "llvm.gc", then "llvm.gc.experimental", then
57   // "llvm.gc.experimental.statepoint", and then we will stop as the range is
58   // size 1. During the search, we can skip the prefix that we already know is
59   // identical. By using strncmp we consider names with differing suffixes to
60   // be part of the equal range.
61   size_t CmpStart = 0;
62   size_t CmpEnd = 4; // Skip the "llvm" component.
63   const char *const *Low = NameTable.begin();
64   const char *const *High = NameTable.end();
65   const char *const *LastLow = Low;
66   while (CmpEnd < Name.size() && High - Low > 0) {
67     CmpStart = CmpEnd;
68     CmpEnd = Name.find('.', CmpStart + 1);
69     CmpEnd = CmpEnd == StringRef::npos ? Name.size() : CmpEnd;
70     auto Cmp = [CmpStart, CmpEnd](const char *LHS, const char *RHS) {
71       return strncmp(LHS + CmpStart, RHS + CmpStart, CmpEnd - CmpStart) < 0;
72     };
73     LastLow = Low;
74     std::tie(Low, High) = std::equal_range(Low, High, Name.data(), Cmp);
75   }
76   if (High - Low > 0)
77     LastLow = Low;
78 
79   if (LastLow == NameTable.end())
80     return -1;
81   StringRef NameFound = *LastLow;
82   if (Name == NameFound ||
83       (Name.startswith(NameFound) && Name[NameFound.size()] == '.'))
84     return LastLow - NameTable.begin();
85   return -1;
86 }
87 
88 Value *InstrProfIncrementInst::getStep() const {
89   if (InstrProfIncrementInstStep::classof(this)) {
90     return const_cast<Value *>(getArgOperand(4));
91   }
92   const Module *M = getModule();
93   LLVMContext &Context = M->getContext();
94   return ConstantInt::get(Type::getInt64Ty(Context), 1);
95 }
96