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