1 //===----------- JITSymbol.cpp - JITSymbol class implementation -----------===//
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 // JITSymbol class implementation plus helper functions.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "llvm/ExecutionEngine/JITSymbol.h"
14 #include "llvm/IR/Function.h"
15 #include "llvm/IR/GlobalAlias.h"
16 #include "llvm/IR/GlobalValue.h"
17 #include "llvm/IR/ModuleSummaryIndex.h"
18 #include "llvm/Object/ObjectFile.h"
19
20 using namespace llvm;
21
fromGlobalValue(const GlobalValue & GV)22 JITSymbolFlags llvm::JITSymbolFlags::fromGlobalValue(const GlobalValue &GV) {
23 assert(GV.hasName() && "Can't get flags for anonymous symbol");
24
25 JITSymbolFlags Flags = JITSymbolFlags::None;
26 if (GV.hasWeakLinkage() || GV.hasLinkOnceLinkage())
27 Flags |= JITSymbolFlags::Weak;
28 if (GV.hasCommonLinkage())
29 Flags |= JITSymbolFlags::Common;
30 if (!GV.hasLocalLinkage() && !GV.hasHiddenVisibility())
31 Flags |= JITSymbolFlags::Exported;
32
33 if (isa<Function>(GV))
34 Flags |= JITSymbolFlags::Callable;
35 else if (isa<GlobalAlias>(GV) &&
36 isa<Function>(cast<GlobalAlias>(GV).getAliasee()))
37 Flags |= JITSymbolFlags::Callable;
38
39 // Check for a linker-private-global-prefix on the symbol name, in which
40 // case it must be marked as non-exported.
41 if (auto *M = GV.getParent()) {
42 const auto &DL = M->getDataLayout();
43 StringRef LPGP = DL.getLinkerPrivateGlobalPrefix();
44 if (!LPGP.empty() && GV.getName().front() == '\01' &&
45 GV.getName().substr(1).startswith(LPGP))
46 Flags &= ~JITSymbolFlags::Exported;
47 }
48
49 return Flags;
50 }
51
fromSummary(GlobalValueSummary * S)52 JITSymbolFlags llvm::JITSymbolFlags::fromSummary(GlobalValueSummary *S) {
53 JITSymbolFlags Flags = JITSymbolFlags::None;
54 auto L = S->linkage();
55 if (GlobalValue::isWeakLinkage(L) || GlobalValue::isLinkOnceLinkage(L))
56 Flags |= JITSymbolFlags::Weak;
57 if (GlobalValue::isCommonLinkage(L))
58 Flags |= JITSymbolFlags::Common;
59 if (GlobalValue::isExternalLinkage(L) || GlobalValue::isExternalWeakLinkage(L))
60 Flags |= JITSymbolFlags::Exported;
61
62 if (isa<FunctionSummary>(S))
63 Flags |= JITSymbolFlags::Callable;
64
65 return Flags;
66 }
67
68 Expected<JITSymbolFlags>
fromObjectSymbol(const object::SymbolRef & Symbol)69 llvm::JITSymbolFlags::fromObjectSymbol(const object::SymbolRef &Symbol) {
70 Expected<uint32_t> SymbolFlagsOrErr = Symbol.getFlags();
71 if (!SymbolFlagsOrErr)
72 // TODO: Test this error.
73 return SymbolFlagsOrErr.takeError();
74
75 JITSymbolFlags Flags = JITSymbolFlags::None;
76 if (*SymbolFlagsOrErr & object::BasicSymbolRef::SF_Weak)
77 Flags |= JITSymbolFlags::Weak;
78 if (*SymbolFlagsOrErr & object::BasicSymbolRef::SF_Common)
79 Flags |= JITSymbolFlags::Common;
80 if (*SymbolFlagsOrErr & object::BasicSymbolRef::SF_Exported)
81 Flags |= JITSymbolFlags::Exported;
82
83 auto SymbolType = Symbol.getType();
84 if (!SymbolType)
85 return SymbolType.takeError();
86
87 if (*SymbolType == object::SymbolRef::ST_Function)
88 Flags |= JITSymbolFlags::Callable;
89
90 return Flags;
91 }
92
93 ARMJITSymbolFlags
fromObjectSymbol(const object::SymbolRef & Symbol)94 llvm::ARMJITSymbolFlags::fromObjectSymbol(const object::SymbolRef &Symbol) {
95 Expected<uint32_t> SymbolFlagsOrErr = Symbol.getFlags();
96 if (!SymbolFlagsOrErr)
97 // TODO: Actually report errors helpfully.
98 report_fatal_error(SymbolFlagsOrErr.takeError());
99 ARMJITSymbolFlags Flags;
100 if (*SymbolFlagsOrErr & object::BasicSymbolRef::SF_Thumb)
101 Flags |= ARMJITSymbolFlags::Thumb;
102 return Flags;
103 }
104
105 /// Performs lookup by, for each symbol, first calling
106 /// findSymbolInLogicalDylib and if that fails calling
107 /// findSymbol.
lookup(const LookupSet & Symbols,OnResolvedFunction OnResolved)108 void LegacyJITSymbolResolver::lookup(const LookupSet &Symbols,
109 OnResolvedFunction OnResolved) {
110 JITSymbolResolver::LookupResult Result;
111 for (auto &Symbol : Symbols) {
112 std::string SymName = Symbol.str();
113 if (auto Sym = findSymbolInLogicalDylib(SymName)) {
114 if (auto AddrOrErr = Sym.getAddress())
115 Result[Symbol] = JITEvaluatedSymbol(*AddrOrErr, Sym.getFlags());
116 else {
117 OnResolved(AddrOrErr.takeError());
118 return;
119 }
120 } else if (auto Err = Sym.takeError()) {
121 OnResolved(std::move(Err));
122 return;
123 } else {
124 // findSymbolInLogicalDylib failed. Lets try findSymbol.
125 if (auto Sym = findSymbol(SymName)) {
126 if (auto AddrOrErr = Sym.getAddress())
127 Result[Symbol] = JITEvaluatedSymbol(*AddrOrErr, Sym.getFlags());
128 else {
129 OnResolved(AddrOrErr.takeError());
130 return;
131 }
132 } else if (auto Err = Sym.takeError()) {
133 OnResolved(std::move(Err));
134 return;
135 } else {
136 OnResolved(make_error<StringError>("Symbol not found: " + Symbol,
137 inconvertibleErrorCode()));
138 return;
139 }
140 }
141 }
142
143 OnResolved(std::move(Result));
144 }
145
146 /// Performs flags lookup by calling findSymbolInLogicalDylib and
147 /// returning the flags value for that symbol.
148 Expected<JITSymbolResolver::LookupSet>
getResponsibilitySet(const LookupSet & Symbols)149 LegacyJITSymbolResolver::getResponsibilitySet(const LookupSet &Symbols) {
150 JITSymbolResolver::LookupSet Result;
151
152 for (auto &Symbol : Symbols) {
153 std::string SymName = Symbol.str();
154 if (auto Sym = findSymbolInLogicalDylib(SymName)) {
155 // If there's an existing def but it is not strong, then the caller is
156 // responsible for it.
157 if (!Sym.getFlags().isStrong())
158 Result.insert(Symbol);
159 } else if (auto Err = Sym.takeError())
160 return std::move(Err);
161 else {
162 // If there is no existing definition then the caller is responsible for
163 // it.
164 Result.insert(Symbol);
165 }
166 }
167
168 return std::move(Result);
169 }
170