1 | //===---------------------- TableManager.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 | // Fix edge for edge that needs an entry to reference the target symbol |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | #ifndef LLVM_EXECUTIONENGINE_JITLINK_TABLEMANAGER_H |
14 | #define LLVM_EXECUTIONENGINE_JITLINK_TABLEMANAGER_H |
15 | |
16 | #include "llvm/ExecutionEngine/JITLink/JITLink.h" |
17 | #include "llvm/Support/Debug.h" |
18 | |
19 | namespace llvm { |
20 | namespace jitlink { |
21 | |
22 | /// A CRTP base for tables that are built on demand, e.g. Global Offset Tables |
23 | /// and Procedure Linkage Tables. |
24 | /// The getEntyrForTarget function returns the table entry corresponding to the |
25 | /// given target, calling down to the implementation class to build an entry if |
26 | /// one does not already exist. |
27 | template <typename TableManagerImplT> class TableManager { |
28 | public: |
29 | /// Return the constructed entry |
30 | /// |
31 | /// Use parameter G to construct the entry for target symbol |
32 | Symbol &getEntryForTarget(LinkGraph &G, Symbol &Target) { |
33 | assert(Target.hasName() && "Edge cannot point to anonymous target" ); |
34 | |
35 | auto EntryI = Entries.find(Val: Target.getName()); |
36 | |
37 | // Build the entry if it doesn't exist. |
38 | if (EntryI == Entries.end()) { |
39 | auto &Entry = impl().createEntry(G, Target); |
40 | DEBUG_WITH_TYPE("jitlink" , { |
41 | dbgs() << " Created " << impl().getSectionName() << " entry for " |
42 | << Target.getName() << ": " << Entry << "\n" ; |
43 | }); |
44 | EntryI = Entries.insert(std::make_pair(Target.getName(), &Entry)).first; |
45 | } |
46 | |
47 | assert(EntryI != Entries.end() && "Could not get entry symbol" ); |
48 | DEBUG_WITH_TYPE("jitlink" , { |
49 | dbgs() << " Using " << impl().getSectionName() << " entry " |
50 | << *EntryI->second << "\n" ; |
51 | }); |
52 | return *EntryI->second; |
53 | } |
54 | |
55 | /// Register a pre-existing entry. |
56 | /// |
57 | /// Objects may include pre-existing table entries (e.g. for GOTs). |
58 | /// This method can be used to register those entries so that they will not |
59 | /// be duplicated by createEntry the first time that getEntryForTarget is |
60 | /// called. |
61 | bool registerPreExistingEntry(Symbol &Target, Symbol &Entry) { |
62 | assert(Target.hasName() && "Edge cannot point to anonymous target" ); |
63 | auto Res = Entries.insert(KV: { |
64 | Target.getName(), |
65 | &Entry, |
66 | }); |
67 | return Res.second; |
68 | } |
69 | |
70 | private: |
71 | TableManagerImplT &impl() { return static_cast<TableManagerImplT &>(*this); } |
72 | DenseMap<StringRef, Symbol *> Entries; |
73 | }; |
74 | |
75 | } // namespace jitlink |
76 | } // namespace llvm |
77 | |
78 | #endif |
79 | |