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 <functional>
13 #include <memory>
14 #include <utility>
15 #include <vector>
16 
17 namespace llvm {
18 
19 class Module;
20 class Function;
21 class SlotTracker;
22 class Value;
23 class MDNode;
24 
25 /// Abstract interface of slot tracker storage.
26 class AbstractSlotTrackerStorage {
27 public:
28   virtual ~AbstractSlotTrackerStorage();
29 
30   virtual unsigned getNextMetadataSlot() = 0;
31 
32   virtual void createMetadataSlot(const MDNode *) = 0;
33   virtual int getMetadataSlot(const MDNode *) = 0;
34 };
35 
36 /// Manage lifetime of a slot tracker for printing IR.
37 ///
38 /// Wrapper around the \a SlotTracker used internally by \a AsmWriter.  This
39 /// class allows callers to share the cost of incorporating the metadata in a
40 /// module or a function.
41 ///
42 /// If the IR changes from underneath \a ModuleSlotTracker, strings like
43 /// "<badref>" will be printed, or, worse, the wrong slots entirely.
44 class ModuleSlotTracker {
45   /// Storage for a slot tracker.
46   std::unique_ptr<SlotTracker> MachineStorage;
47   bool ShouldCreateStorage = false;
48   bool ShouldInitializeAllMetadata = false;
49 
50   const Module *M = nullptr;
51   const Function *F = nullptr;
52   SlotTracker *Machine = nullptr;
53 
54   std::function<void(AbstractSlotTrackerStorage *, const Module *, bool)>
55       ProcessModuleHookFn;
56   std::function<void(AbstractSlotTrackerStorage *, const Function *, bool)>
57       ProcessFunctionHookFn;
58 
59 public:
60   /// Wrap a preinitialized SlotTracker.
61   ModuleSlotTracker(SlotTracker &Machine, const Module *M,
62                     const Function *F = nullptr);
63 
64   /// Construct a slot tracker from a module.
65   ///
66   /// If \a M is \c nullptr, uses a null slot tracker.  Otherwise, initializes
67   /// a slot tracker, and initializes all metadata slots.  \c
68   /// ShouldInitializeAllMetadata defaults to true because this is expected to
69   /// be shared between multiple callers, and otherwise MDNode references will
70   /// not match up.
71   explicit ModuleSlotTracker(const Module *M,
72                              bool ShouldInitializeAllMetadata = true);
73 
74   /// Destructor to clean up storage.
75   virtual ~ModuleSlotTracker();
76 
77   /// Lazily creates a slot tracker.
78   SlotTracker *getMachine();
79 
80   const Module *getModule() const { return M; }
81   const Function *getCurrentFunction() const { return F; }
82 
83   /// Incorporate the given function.
84   ///
85   /// Purge the currently incorporated function and incorporate \c F.  If \c F
86   /// is currently incorporated, this is a no-op.
87   void incorporateFunction(const Function &F);
88 
89   /// Return the slot number of the specified local value.
90   ///
91   /// A function that defines this value should be incorporated prior to calling
92   /// this method.
93   /// Return -1 if the value is not in the function's SlotTracker.
94   int getLocalSlot(const Value *V);
95 
96   void setProcessHook(
97       std::function<void(AbstractSlotTrackerStorage *, const Module *, bool)>);
98   void setProcessHook(std::function<void(AbstractSlotTrackerStorage *,
99                                          const Function *, bool)>);
100 
101   using MachineMDNodeListType =
102       std::vector<std::pair<unsigned, const MDNode *>>;
103 
104   void collectMDNodes(MachineMDNodeListType &L, unsigned LB, unsigned UB) const;
105 };
106 
107 } // end namespace llvm
108 
109 #endif
110