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
19namespace llvm {
20namespace 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.
27template <typename TableManagerImplT> class TableManager {
28public:
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
70private:
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

source code of llvm/include/llvm/ExecutionEngine/JITLink/TableManager.h