Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/IR/BasicBlock.h
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//===- llvm/BasicBlock.h - Represent a basic block in the VM ----*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the declaration of the BasicBlock class.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_IR_BASICBLOCK_H
14
#define LLVM_IR_BASICBLOCK_H
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#include "llvm-c/Types.h"
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#include "llvm/ADT/Twine.h"
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#include "llvm/ADT/ilist.h"
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#include "llvm/ADT/ilist_node.h"
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#include "llvm/ADT/iterator.h"
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#include "llvm/ADT/iterator_range.h"
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#include "llvm/IR/Instruction.h"
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#include "llvm/IR/SymbolTableListTraits.h"
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#include "llvm/IR/Value.h"
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#include "llvm/Support/CBindingWrapping.h"
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#include "llvm/Support/Casting.h"
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#include "llvm/Support/Compiler.h"
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#include <cassert>
29
#include <cstddef>
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#include <iterator>
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32
namespace llvm {
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class CallInst;
35
class Function;
36
class LandingPadInst;
37
class LLVMContext;
38
class Module;
39
class PHINode;
40
class ValueSymbolTable;
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42
/// LLVM Basic Block Representation
43
///
44
/// This represents a single basic block in LLVM. A basic block is simply a
45
/// container of instructions that execute sequentially. Basic blocks are Values
46
/// because they are referenced by instructions such as branches and switch
47
/// tables. The type of a BasicBlock is "Type::LabelTy" because the basic block
48
/// represents a label to which a branch can jump.
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///
50
/// A well formed basic block is formed of a list of non-terminating
51
/// instructions followed by a single terminator instruction. Terminator
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/// instructions may not occur in the middle of basic blocks, and must terminate
53
/// the blocks. The BasicBlock class allows malformed basic blocks to occur
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/// because it may be useful in the intermediate stage of constructing or
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/// modifying a program. However, the verifier will ensure that basic blocks are
56
/// "well formed".
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class BasicBlock final : public Value, // Basic blocks are data objects also
58
                         public ilist_node_with_parent<BasicBlock, Function> {
59
public:
60
  using InstListType = SymbolTableList<Instruction>;
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private:
63
  friend class BlockAddress;
64
  friend class SymbolTableListTraits<BasicBlock>;
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66
  InstListType InstList;
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  Function *Parent;
68
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  void setParent(Function *parent);
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  /// Constructor.
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  ///
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  /// If the function parameter is specified, the basic block is automatically
74
  /// inserted at either the end of the function (if InsertBefore is null), or
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  /// before the specified basic block.
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  explicit BasicBlock(LLVMContext &C, const Twine &Name = "",
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                      Function *Parent = nullptr,
78
                      BasicBlock *InsertBefore = nullptr);
79
80
public:
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  BasicBlock(const BasicBlock &) = delete;
82
  BasicBlock &operator=(const BasicBlock &) = delete;
83
  ~BasicBlock();
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85
  /// Get the context in which this basic block lives.
86
  LLVMContext &getContext() const;
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88
  /// Instruction iterators...
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  using iterator = InstListType::iterator;
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  using const_iterator = InstListType::const_iterator;
91
  using reverse_iterator = InstListType::reverse_iterator;
92
  using const_reverse_iterator = InstListType::const_reverse_iterator;
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94
  /// Creates a new BasicBlock.
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  ///
96
  /// If the Parent parameter is specified, the basic block is automatically
97
  /// inserted at either the end of the function (if InsertBefore is 0), or
98
  /// before the specified basic block.
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  static BasicBlock *Create(LLVMContext &Context, const Twine &Name = "",
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                            Function *Parent = nullptr,
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7.46M
                            BasicBlock *InsertBefore = nullptr) {
102
7.46M
    return new BasicBlock(Context, Name, Parent, InsertBefore);
103
7.46M
  }
104
105
  /// Return the enclosing method, or null if none.
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374M
  const Function *getParent() const { return Parent; }
107
180M
        Function *getParent()       { return Parent; }
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109
  /// Return the module owning the function this basic block belongs to, or
110
  /// nullptr if the function does not have a module.
111
  ///
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  /// Note: this is undefined behavior if the block does not have a parent.
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  const Module *getModule() const;
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108M
  Module *getModule() {
115
108M
    return const_cast<Module *>(
116
108M
                            static_cast<const BasicBlock *>(this)->getModule());
117
108M
  }
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119
  /// Returns the terminator instruction if the block is well formed or null
120
  /// if the block is not well formed.
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  const Instruction *getTerminator() const LLVM_READONLY;
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1.48G
  Instruction *getTerminator() {
123
1.48G
    return const_cast<Instruction *>(
124
1.48G
        static_cast<const BasicBlock *>(this)->getTerminator());
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1.48G
  }
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  /// Returns the call instruction calling \@llvm.experimental.deoptimize
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  /// prior to the terminating return instruction of this basic block, if such
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  /// a call is present.  Otherwise, returns null.
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  const CallInst *getTerminatingDeoptimizeCall() const;
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2.20k
  CallInst *getTerminatingDeoptimizeCall() {
132
2.20k
    return const_cast<CallInst *>(
133
2.20k
         static_cast<const BasicBlock *>(this)->getTerminatingDeoptimizeCall());
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2.20k
  }
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  /// Returns the call instruction marked 'musttail' prior to the terminating
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  /// return instruction of this basic block, if such a call is present.
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  /// Otherwise, returns null.
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  const CallInst *getTerminatingMustTailCall() const;
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729k
  CallInst *getTerminatingMustTailCall() {
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729k
    return const_cast<CallInst *>(
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729k
           static_cast<const BasicBlock *>(this)->getTerminatingMustTailCall());
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729k
  }
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  /// Returns a pointer to the first instruction in this block that is not a
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  /// PHINode instruction.
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  ///
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  /// When adding instructions to the beginning of the basic block, they should
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  /// be added before the returned value, not before the first instruction,
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  /// which might be PHI. Returns 0 is there's no non-PHI instruction.
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  const Instruction* getFirstNonPHI() const;
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2.36M
  Instruction* getFirstNonPHI() {
153
2.36M
    return const_cast<Instruction *>(
154
2.36M
                       static_cast<const BasicBlock *>(this)->getFirstNonPHI());
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2.36M
  }
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157
  /// Returns a pointer to the first instruction in this block that is not a
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  /// PHINode or a debug intrinsic.
159
  const Instruction* getFirstNonPHIOrDbg() const;
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24.4M
  Instruction* getFirstNonPHIOrDbg() {
161
24.4M
    return const_cast<Instruction *>(
162
24.4M
                  static_cast<const BasicBlock *>(this)->getFirstNonPHIOrDbg());
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24.4M
  }
164
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  /// Returns a pointer to the first instruction in this block that is not a
166
  /// PHINode, a debug intrinsic, or a lifetime intrinsic.
167
  const Instruction* getFirstNonPHIOrDbgOrLifetime() const;
168
123
  Instruction* getFirstNonPHIOrDbgOrLifetime() {
169
123
    return const_cast<Instruction *>(
170
123
        static_cast<const BasicBlock *>(this)->getFirstNonPHIOrDbgOrLifetime());
171
123
  }
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  /// Returns an iterator to the first instruction in this block that is
174
  /// suitable for inserting a non-PHI instruction.
175
  ///
176
  /// In particular, it skips all PHIs and LandingPad instructions.
177
  const_iterator getFirstInsertionPt() const;
178
1.98M
  iterator getFirstInsertionPt() {
179
1.98M
    return static_cast<const BasicBlock *>(this)
180
1.98M
                                          ->getFirstInsertionPt().getNonConst();
181
1.98M
  }
182
183
  /// Return a const iterator range over the instructions in the block, skipping
184
  /// any debug instructions.
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  iterator_range<filter_iterator<BasicBlock::const_iterator,
186
                                 std::function<bool(const Instruction &)>>>
187
  instructionsWithoutDebug() const;
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  /// Return an iterator range over the instructions in the block, skipping any
190
  /// debug instructions.
191
  iterator_range<filter_iterator<BasicBlock::iterator,
192
                                 std::function<bool(Instruction &)>>>
193
  instructionsWithoutDebug();
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  /// Unlink 'this' from the containing function, but do not delete it.
196
  void removeFromParent();
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  /// Unlink 'this' from the containing function and delete it.
199
  ///
200
  // \returns an iterator pointing to the element after the erased one.
201
  SymbolTableList<BasicBlock>::iterator eraseFromParent();
202
203
  /// Unlink this basic block from its current function and insert it into
204
  /// the function that \p MovePos lives in, right before \p MovePos.
205
  void moveBefore(BasicBlock *MovePos);
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  /// Unlink this basic block from its current function and insert it
208
  /// right after \p MovePos in the function \p MovePos lives in.
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  void moveAfter(BasicBlock *MovePos);
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  /// Insert unlinked basic block into a function.
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  ///
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  /// Inserts an unlinked basic block into \c Parent.  If \c InsertBefore is
214
  /// provided, inserts before that basic block, otherwise inserts at the end.
215
  ///
216
  /// \pre \a getParent() is \c nullptr.
217
  void insertInto(Function *Parent, BasicBlock *InsertBefore = nullptr);
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  /// Return the predecessor of this block if it has a single predecessor
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  /// block. Otherwise return a null pointer.
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  const BasicBlock *getSinglePredecessor() const;
222
177M
  BasicBlock *getSinglePredecessor() {
223
177M
    return const_cast<BasicBlock *>(
224
177M
                 static_cast<const BasicBlock *>(this)->getSinglePredecessor());
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177M
  }
226
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  /// Return the predecessor of this block if it has a unique predecessor
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  /// block. Otherwise return a null pointer.
229
  ///
230
  /// Note that unique predecessor doesn't mean single edge, there can be
231
  /// multiple edges from the unique predecessor to this block (for example a
232
  /// switch statement with multiple cases having the same destination).
233
  const BasicBlock *getUniquePredecessor() const;
234
37.8M
  BasicBlock *getUniquePredecessor() {
235
37.8M
    return const_cast<BasicBlock *>(
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37.8M
                 static_cast<const BasicBlock *>(this)->getUniquePredecessor());
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37.8M
  }
238
239
  /// Return true if this block has exactly N predecessors.
240
  bool hasNPredecessors(unsigned N) const;
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  /// Return true if this block has N predecessors or more.
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  bool hasNPredecessorsOrMore(unsigned N) const;
244
245
  /// Return the successor of this block if it has a single successor.
246
  /// Otherwise return a null pointer.
247
  ///
248
  /// This method is analogous to getSinglePredecessor above.
249
  const BasicBlock *getSingleSuccessor() const;
250
45.1M
  BasicBlock *getSingleSuccessor() {
251
45.1M
    return const_cast<BasicBlock *>(
252
45.1M
                   static_cast<const BasicBlock *>(this)->getSingleSuccessor());
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45.1M
  }
254
255
  /// Return the successor of this block if it has a unique successor.
256
  /// Otherwise return a null pointer.
257
  ///
258
  /// This method is analogous to getUniquePredecessor above.
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  const BasicBlock *getUniqueSuccessor() const;
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19.9M
  BasicBlock *getUniqueSuccessor() {
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19.9M
    return const_cast<BasicBlock *>(
262
19.9M
                   static_cast<const BasicBlock *>(this)->getUniqueSuccessor());
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19.9M
  }
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  //===--------------------------------------------------------------------===//
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  /// Instruction iterator methods
267
  ///
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695M
  inline iterator                begin()       { return InstList.begin(); }
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88.3M
  inline const_iterator          begin() const { return InstList.begin(); }
270
673M
  inline iterator                end  ()       { return InstList.end();   }
271
122M
  inline const_iterator          end  () const { return InstList.end();   }
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11.8M
  inline reverse_iterator        rbegin()       { return InstList.rbegin(); }
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0
  inline const_reverse_iterator  rbegin() const { return InstList.rbegin(); }
275
34.9M
  inline reverse_iterator        rend  ()       { return InstList.rend();   }
276
0
  inline const_reverse_iterator  rend  () const { return InstList.rend();   }
277
278
3.17M
  inline size_t                   size() const { return InstList.size();  }
279
54.2M
  inline bool                    empty() const { return InstList.empty(); }
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966k
  inline const Instruction      &front() const { return InstList.front(); }
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11.9M
  inline       Instruction      &front()       { return InstList.front(); }
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1.36M
  inline const Instruction       &back() const { return InstList.back();  }
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831k
  inline       Instruction       &back()       { return InstList.back();  }
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285
  /// Iterator to walk just the phi nodes in the basic block.
286
  template <typename PHINodeT = PHINode, typename BBIteratorT = iterator>
287
  class phi_iterator_impl
288
      : public iterator_facade_base<phi_iterator_impl<PHINodeT, BBIteratorT>,
289
                                    std::forward_iterator_tag, PHINodeT> {
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    friend BasicBlock;
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    PHINodeT *PN;
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92.0M
    phi_iterator_impl(PHINodeT *PN) : PN(PN) {}
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296
  public:
297
    // Allow default construction to build variables, but this doesn't build
298
    // a useful iterator.
299
    phi_iterator_impl() = default;
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    // Allow conversion between instantiations where valid.
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    template <typename PHINodeU, typename BBIteratorU>
303
    phi_iterator_impl(const phi_iterator_impl<PHINodeU, BBIteratorU> &Arg)
304
8.55M
        : PN(Arg.PN) {}
305
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65.0M
    bool operator==(const phi_iterator_impl &Arg) const { return PN == Arg.PN; }
llvm::BasicBlock::phi_iterator_impl<llvm::PHINode, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, false> >::operator==(llvm::BasicBlock::phi_iterator_impl<llvm::PHINode, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, false> > const&) const
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Source
306
59.4M
    bool operator==(const phi_iterator_impl &Arg) const { return PN == Arg.PN; }
llvm::BasicBlock::phi_iterator_impl<llvm::PHINode const, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, true> >::operator==(llvm::BasicBlock::phi_iterator_impl<llvm::PHINode const, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, true> > const&) const
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Count
Source
306
5.56M
    bool operator==(const phi_iterator_impl &Arg) const { return PN == Arg.PN; }
307
308
19.3M
    PHINodeT &operator*() const { return *PN; }
llvm::BasicBlock::phi_iterator_impl<llvm::PHINode, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, false> >::operator*() const
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Source
308
18.0M
    PHINodeT &operator*() const { return *PN; }
llvm::BasicBlock::phi_iterator_impl<llvm::PHINode const, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, true> >::operator*() const
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Source
308
1.30M
    PHINodeT &operator*() const { return *PN; }
309
310
    using phi_iterator_impl::iterator_facade_base::operator++;
311
18.9M
    phi_iterator_impl &operator++() {
312
18.9M
      assert(PN && "Cannot increment the end iterator!");
313
18.9M
      PN = dyn_cast<PHINodeT>(std::next(BBIteratorT(PN)));
314
18.9M
      return *this;
315
18.9M
    }
llvm::BasicBlock::phi_iterator_impl<llvm::PHINode, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, false> >::operator++()
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Count
Source
311
17.6M
    phi_iterator_impl &operator++() {
312
17.6M
      assert(PN && "Cannot increment the end iterator!");
313
17.6M
      PN = dyn_cast<PHINodeT>(std::next(BBIteratorT(PN)));
314
17.6M
      return *this;
315
17.6M
    }
llvm::BasicBlock::phi_iterator_impl<llvm::PHINode const, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, false, false, void>, false, true> >::operator++()
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Count
Source
311
1.28M
    phi_iterator_impl &operator++() {
312
1.28M
      assert(PN && "Cannot increment the end iterator!");
313
1.28M
      PN = dyn_cast<PHINodeT>(std::next(BBIteratorT(PN)));
314
1.28M
      return *this;
315
1.28M
    }
316
  };
317
  using phi_iterator = phi_iterator_impl<>;
318
  using const_phi_iterator =
319
      phi_iterator_impl<const PHINode, BasicBlock::const_iterator>;
320
321
  /// Returns a range that iterates over the phis in the basic block.
322
  ///
323
  /// Note that this cannot be used with basic blocks that have no terminator.
324
4.27M
  iterator_range<const_phi_iterator> phis() const {
325
4.27M
    return const_cast<BasicBlock *>(this)->phis();
326
4.27M
  }
327
  iterator_range<phi_iterator> phis();
328
329
  /// Return the underlying instruction list container.
330
  ///
331
  /// Currently you need to access the underlying instruction list container
332
  /// directly if you want to modify it.
333
414
  const InstListType &getInstList() const { return InstList; }
334
86.7M
        InstListType &getInstList()       { return InstList; }
335
336
  /// Returns a pointer to a member of the instruction list.
337
128M
  static InstListType BasicBlock::*getSublistAccess(Instruction*) {
338
128M
    return &BasicBlock::InstList;
339
128M
  }
340
341
  /// Returns a pointer to the symbol table if one exists.
342
  ValueSymbolTable *getValueSymbolTable();
343
344
  /// Methods for support type inquiry through isa, cast, and dyn_cast.
345
0
  static bool classof(const Value *V) {
346
0
    return V->getValueID() == Value::BasicBlockVal;
347
0
  }
348
349
  /// Cause all subinstructions to "let go" of all the references that said
350
  /// subinstructions are maintaining.
351
  ///
352
  /// This allows one to 'delete' a whole class at a time, even though there may
353
  /// be circular references... first all references are dropped, and all use
354
  /// counts go to zero.  Then everything is delete'd for real.  Note that no
355
  /// operations are valid on an object that has "dropped all references",
356
  /// except operator delete.
357
  void dropAllReferences();
358
359
  /// Notify the BasicBlock that the predecessor \p Pred is no longer able to
360
  /// reach it.
361
  ///
362
  /// This is actually not used to update the Predecessor list, but is actually
363
  /// used to update the PHI nodes that reside in the block.  Note that this
364
  /// should be called while the predecessor still refers to this block.
365
  void removePredecessor(BasicBlock *Pred, bool KeepOneInputPHIs = false);
366
367
  bool canSplitPredecessors() const;
368
369
  /// Split the basic block into two basic blocks at the specified instruction.
370
  ///
371
  /// Note that all instructions BEFORE the specified iterator stay as part of
372
  /// the original basic block, an unconditional branch is added to the original
373
  /// BB, and the rest of the instructions in the BB are moved to the new BB,
374
  /// including the old terminator.  The newly formed BasicBlock is returned.
375
  /// This function invalidates the specified iterator.
376
  ///
377
  /// Note that this only works on well formed basic blocks (must have a
378
  /// terminator), and 'I' must not be the end of instruction list (which would
379
  /// cause a degenerate basic block to be formed, having a terminator inside of
380
  /// the basic block).
381
  ///
382
  /// Also note that this doesn't preserve any passes. To split blocks while
383
  /// keeping loop information consistent, use the SplitBlock utility function.
384
  BasicBlock *splitBasicBlock(iterator I, const Twine &BBName = "");
385
73.1k
  BasicBlock *splitBasicBlock(Instruction *I, const Twine &BBName = "") {
386
73.1k
    return splitBasicBlock(I->getIterator(), BBName);
387
73.1k
  }
388
389
  /// Returns true if there are any uses of this basic block other than
390
  /// direct branches, switches, etc. to it.
391
56.2M
  bool hasAddressTaken() const { return getSubclassDataFromValue() != 0; }
392
393
  /// Update all phi nodes in this basic block to refer to basic block \p New
394
  /// instead of basic block \p Old.
395
  void replacePhiUsesWith(BasicBlock *Old, BasicBlock *New);
396
397
  /// Update all phi nodes in this basic block's successors to refer to basic
398
  /// block \p New instead of basic block \p Old.
399
  void replaceSuccessorsPhiUsesWith(BasicBlock *Old, BasicBlock *New);
400
401
  /// Update all phi nodes in this basic block's successors to refer to basic
402
  /// block \p New instead of to it.
403
  void replaceSuccessorsPhiUsesWith(BasicBlock *New);
404
405
  /// Return true if this basic block is an exception handling block.
406
9.16M
  bool isEHPad() const { return getFirstNonPHI()->isEHPad(); }
407
408
  /// Return true if this basic block is a landing pad.
409
  ///
410
  /// Being a ``landing pad'' means that the basic block is the destination of
411
  /// the 'unwind' edge of an invoke instruction.
412
  bool isLandingPad() const;
413
414
  /// Return the landingpad instruction associated with the landing pad.
415
  const LandingPadInst *getLandingPadInst() const;
416
2.54M
  LandingPadInst *getLandingPadInst() {
417
2.54M
    return const_cast<LandingPadInst *>(
418
2.54M
                    static_cast<const BasicBlock *>(this)->getLandingPadInst());
419
2.54M
  }
420
421
  /// Return true if it is legal to hoist instructions into this block.
422
  bool isLegalToHoistInto() const;
423
424
  Optional<uint64_t> getIrrLoopHeaderWeight() const;
425
426
private:
427
  /// Increment the internal refcount of the number of BlockAddresses
428
  /// referencing this BasicBlock by \p Amt.
429
  ///
430
  /// This is almost always 0, sometimes one possibly, but almost never 2, and
431
  /// inconceivably 3 or more.
432
2.06k
  void AdjustBlockAddressRefCount(int Amt) {
433
2.06k
    setValueSubclassData(getSubclassDataFromValue()+Amt);
434
2.06k
    assert((int)(signed char)getSubclassDataFromValue() >= 0 &&
435
2.06k
           "Refcount wrap-around");
436
2.06k
  }
437
438
  /// Shadow Value::setValueSubclassData with a private forwarding method so
439
  /// that any future subclasses cannot accidentally use it.
440
2.06k
  void setValueSubclassData(unsigned short D) {
441
2.06k
    Value::setValueSubclassData(D);
442
2.06k
  }
443
};
444
445
// Create wrappers for C Binding types (see CBindingWrapping.h).
446
DEFINE_SIMPLE_CONVERSION_FUNCTIONS(BasicBlock, LLVMBasicBlockRef)
447
448
/// Advance \p It while it points to a debug instruction and return the result.
449
/// This assumes that \p It is not at the end of a block.
450
BasicBlock::iterator skipDebugIntrinsics(BasicBlock::iterator It);
451
452
} // end namespace llvm
453
454
#endif // LLVM_IR_BASICBLOCK_H