1//===---------------- EPCDynamicLibrarySearchGenerator.cpp ----------------===//
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#include "llvm/ExecutionEngine/Orc/EPCDynamicLibrarySearchGenerator.h"
10
11#include "llvm/ExecutionEngine/Orc/AbsoluteSymbols.h"
12#include "llvm/ExecutionEngine/Orc/DebugUtils.h"
13#include "llvm/Support/Error.h"
14
15#define DEBUG_TYPE "orc"
16
17namespace llvm {
18namespace orc {
19
20Expected<std::unique_ptr<EPCDynamicLibrarySearchGenerator>>
21EPCDynamicLibrarySearchGenerator::Load(
22 ExecutionSession &ES, DylibManager &DylibMgr, const char *LibraryPath,
23 SymbolPredicate Allow, AddAbsoluteSymbolsFn AddAbsoluteSymbols) {
24 auto Handle = DylibMgr.loadDylib(DylibPath: LibraryPath);
25 if (!Handle)
26 return Handle.takeError();
27
28 return std::make_unique<EPCDynamicLibrarySearchGenerator>(
29 args&: ES, args&: DylibMgr, args&: *Handle, args: std::move(Allow), args: std::move(AddAbsoluteSymbols));
30}
31
32Error EPCDynamicLibrarySearchGenerator::tryToGenerate(
33 LookupState &LS, LookupKind K, JITDylib &JD,
34 JITDylibLookupFlags JDLookupFlags, const SymbolLookupSet &Symbols) {
35
36 if (Symbols.empty())
37 return Error::success();
38
39 LLVM_DEBUG({
40 dbgs() << "EPCDynamicLibrarySearchGenerator trying to generate "
41 << Symbols << "\n";
42 });
43
44 // If there's no handle then resolve all requested symbols to null.
45 if (!H) {
46 assert(Allow && "No handle or filter?");
47 SymbolMap Nulls;
48 for (auto &[Name, LookupFlags] : Symbols) {
49 if (Allow(Name))
50 Nulls[Name] = {};
51 }
52 return addAbsolutes(JD, Symbols: std::move(Nulls));
53 }
54
55 // Otherwise proceed with lookup in the remote.
56 SymbolLookupSet LookupSymbols;
57
58 for (auto &KV : Symbols) {
59 // Skip symbols that don't match the filter.
60 if (Allow && !Allow(KV.first))
61 continue;
62 LookupSymbols.add(Name: KV.first, Flags: SymbolLookupFlags::WeaklyReferencedSymbol);
63 }
64
65 DylibManager::LookupRequest Request(*H, LookupSymbols);
66 // Copy-capture LookupSymbols, since LookupRequest keeps a reference.
67 DylibMgr.lookupSymbolsAsync(Request, F: [this, &JD, LS = std::move(LS),
68 LookupSymbols](auto Result) mutable {
69 if (!Result) {
70 LLVM_DEBUG({
71 dbgs() << "EPCDynamicLibrarySearchGenerator lookup failed due to error";
72 });
73 return LS.continueLookup(Err: Result.takeError());
74 }
75
76 assert(Result->size() == 1 && "Results for more than one library returned");
77 assert(Result->front().size() == LookupSymbols.size() &&
78 "Result has incorrect number of elements");
79
80 auto SymsIt = Result->front().begin();
81 SymbolNameSet MissingSymbols;
82 SymbolMap NewSymbols;
83 for (auto &[Name, Flags] : LookupSymbols) {
84 const auto &Sym = *SymsIt++;
85 if (Sym && Sym->getAddress())
86 NewSymbols[Name] = *Sym;
87 else if (LLVM_UNLIKELY(!Sym &&
88 Flags == SymbolLookupFlags::RequiredSymbol))
89 MissingSymbols.insert(V: Name);
90 }
91
92 LLVM_DEBUG({
93 dbgs() << "EPCDynamicLibrarySearchGenerator lookup returned "
94 << NewSymbols << "\n";
95 });
96
97 // If there were no resolved symbols bail out.
98 if (NewSymbols.empty())
99 return LS.continueLookup(Err: Error::success());
100
101 if (LLVM_UNLIKELY(!MissingSymbols.empty()))
102 return LS.continueLookup(Err: make_error<SymbolsNotFound>(
103 Args: this->ES.getSymbolStringPool(), Args: std::move(MissingSymbols)));
104
105 // Define resolved symbols.
106 Error Err = addAbsolutes(JD, Symbols: std::move(NewSymbols));
107
108 LS.continueLookup(Err: std::move(Err));
109 });
110
111 return Error::success();
112}
113
114Error EPCDynamicLibrarySearchGenerator::addAbsolutes(JITDylib &JD,
115 SymbolMap Symbols) {
116 return AddAbsoluteSymbols ? AddAbsoluteSymbols(JD, std::move(Symbols))
117 : JD.define(MU: absoluteSymbols(Symbols: std::move(Symbols)));
118}
119
120} // end namespace orc
121} // end namespace llvm
122