include/llvm/IR/ModuleSlotTracker.h

   1 //===-- llvm/IR/ModuleSlotTracker.h -----------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_IR_MODULESLOTTRACKER_H
  10 #define LLVM_IR_MODULESLOTTRACKER_H
  11
  12 #include <memory>
  13
  14 namespace llvm {
  15
  16 class Module;
  17 class Function;
  18 class SlotTracker;
  19 class Value;
  20
  21 /// Manage lifetime of a slot tracker for printing IR.
  22 ///
  23 /// Wrapper around the \a SlotTracker used internally by \a AsmWriter.  This
  24 /// class allows callers to share the cost of incorporating the metadata in a
  25 /// module or a function.
  26 ///
  27 /// If the IR changes from underneath \a ModuleSlotTracker, strings like
  28 /// "<badref>" will be printed, or, worse, the wrong slots entirely.
  29 class ModuleSlotTracker {
  30   /// Storage for a slot tracker.
  31   std::unique_ptr<SlotTracker> MachineStorage;
  32   bool ShouldCreateStorage = false;
  33   bool ShouldInitializeAllMetadata = false;
  34
  35   const Module *M = nullptr;
  36   const Function *F = nullptr;
  37   SlotTracker *Machine = nullptr;
  38
  39 public:
  40   /// Wrap a preinitialized SlotTracker.
  41   ModuleSlotTracker(SlotTracker &Machine, const Module *M,
  42                     const Function *F = nullptr);
  43
  44   /// Construct a slot tracker from a module.
  45   ///
  46   /// If \a M is \c nullptr, uses a null slot tracker.  Otherwise, initializes
  47   /// a slot tracker, and initializes all metadata slots.  \c
  48   /// ShouldInitializeAllMetadata defaults to true because this is expected to
  49   /// be shared between multiple callers, and otherwise MDNode references will
  50   /// not match up.
  51   explicit ModuleSlotTracker(const Module *M,
  52                              bool ShouldInitializeAllMetadata = true);
  53
  54   /// Destructor to clean up storage.
  55   ~ModuleSlotTracker();
  56
  57   /// Lazily creates a slot tracker.
  58   SlotTracker *getMachine();
  59
  60   const Module *getModule() const { return M; }
  61   const Function *getCurrentFunction() const { return F; }
  62
  63   /// Incorporate the given function.
  64   ///
  65   /// Purge the currently incorporated function and incorporate \c F.  If \c F
  66   /// is currently incorporated, this is a no-op.
  67   void incorporateFunction(const Function &F);
  68
  69   /// Return the slot number of the specified local value.
  70   ///
  71   /// A function that defines this value should be incorporated prior to calling
  72   /// this method.
  73   /// Return -1 if the value is not in the function's SlotTracker.
  74   int getLocalSlot(const Value *V);
  75 };
  76
  77 } // end namespace llvm
  78
  79 #endif