1 //===--- InterfaceStubFunctionsConsumer.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 "clang/AST/Mangle.h"
10 #include "clang/AST/RecursiveASTVisitor.h"
11 #include "clang/Basic/TargetInfo.h"
12 #include "clang/Frontend/CompilerInstance.h"
13 #include "clang/Frontend/FrontendActions.h"
14 #include "clang/Sema/TemplateInstCallback.h"
15 #include "llvm/BinaryFormat/ELF.h"
16
17 using namespace clang;
18
19 namespace {
20 class InterfaceStubFunctionsConsumer : public ASTConsumer {
21 CompilerInstance &Instance;
22 StringRef InFile;
23 StringRef Format;
24 std::set<std::string> ParsedTemplates;
25
26 enum RootDeclOrigin { TopLevel = 0, FromTU = 1, IsLate = 2 };
27 struct MangledSymbol {
28 std::string ParentName;
29 uint8_t Type;
30 uint8_t Binding;
31 std::vector<std::string> Names;
32 MangledSymbol() = delete;
33
MangledSymbol__anonddb1d4dd0111::InterfaceStubFunctionsConsumer::MangledSymbol34 MangledSymbol(const std::string &ParentName, uint8_t Type, uint8_t Binding,
35 std::vector<std::string> Names)
36 : ParentName(ParentName), Type(Type), Binding(Binding),
37 Names(std::move(Names)) {}
38 };
39 using MangledSymbols = std::map<const NamedDecl *, MangledSymbol>;
40
WriteNamedDecl(const NamedDecl * ND,MangledSymbols & Symbols,int RDO)41 bool WriteNamedDecl(const NamedDecl *ND, MangledSymbols &Symbols, int RDO) {
42 // Here we filter out anything that's not set to DefaultVisibility.
43 // DefaultVisibility is set on a decl when -fvisibility is not specified on
44 // the command line (or specified as default) and the decl does not have
45 // __attribute__((visibility("hidden"))) set or when the command line
46 // argument is set to hidden but the decl explicitly has
47 // __attribute__((visibility ("default"))) set. We do this so that the user
48 // can have fine grain control of what they want to expose in the stub.
49 auto isVisible = [](const NamedDecl *ND) -> bool {
50 return ND->getVisibility() == DefaultVisibility;
51 };
52
53 auto ignoreDecl = [this, isVisible](const NamedDecl *ND) -> bool {
54 if (!isVisible(ND))
55 return true;
56
57 if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
58 if (const auto *Parent = VD->getParentFunctionOrMethod())
59 if (isa<BlockDecl>(Parent) || isa<CXXMethodDecl>(Parent))
60 return true;
61
62 if ((VD->getStorageClass() == StorageClass::SC_Extern) ||
63 (VD->getStorageClass() == StorageClass::SC_Static &&
64 VD->getParentFunctionOrMethod() == nullptr))
65 return true;
66 }
67
68 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
69 if (FD->isInlined() && !isa<CXXMethodDecl>(FD) &&
70 !Instance.getLangOpts().GNUInline)
71 return true;
72 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
73 if (const auto *RC = dyn_cast<CXXRecordDecl>(MD->getParent()))
74 if (isa<ClassTemplateDecl>(RC->getParent()) || !isVisible(RC))
75 return true;
76 if (MD->isDependentContext() || !MD->hasBody())
77 return true;
78 }
79 if (FD->getStorageClass() == StorageClass::SC_Static)
80 return true;
81 }
82 return false;
83 };
84
85 auto getParentFunctionDecl = [](const NamedDecl *ND) -> const NamedDecl * {
86 if (const VarDecl *VD = dyn_cast<VarDecl>(ND))
87 if (const auto *FD =
88 dyn_cast_or_null<FunctionDecl>(VD->getParentFunctionOrMethod()))
89 return FD;
90 return nullptr;
91 };
92
93 auto getMangledNames = [](const NamedDecl *ND) -> std::vector<std::string> {
94 if (!ND)
95 return {""};
96 ASTNameGenerator NameGen(ND->getASTContext());
97 std::vector<std::string> MangledNames = NameGen.getAllManglings(ND);
98 if (isa<CXXConstructorDecl>(ND) || isa<CXXDestructorDecl>(ND))
99 return MangledNames;
100 #ifdef EXPENSIVE_CHECKS
101 assert(MangledNames.size() <= 1 && "Expected only one name mangling.");
102 #endif
103 return {NameGen.getName(ND)};
104 };
105
106 if (!(RDO & FromTU))
107 return true;
108 if (Symbols.find(ND) != Symbols.end())
109 return true;
110 // - Currently have not figured out how to produce the names for FieldDecls.
111 // - Do not want to produce symbols for function paremeters.
112 if (isa<FieldDecl>(ND) || isa<ParmVarDecl>(ND))
113 return true;
114
115 const NamedDecl *ParentDecl = getParentFunctionDecl(ND);
116 if ((ParentDecl && ignoreDecl(ParentDecl)) || ignoreDecl(ND))
117 return true;
118
119 if (RDO & IsLate) {
120 Instance.getDiagnostics().Report(diag::err_asm_invalid_type_in_input)
121 << "Generating Interface Stubs is not supported with "
122 "delayed template parsing.";
123 } else {
124 if (const auto *FD = dyn_cast<FunctionDecl>(ND))
125 if (FD->isDependentContext())
126 return true;
127
128 const bool IsWeak = (ND->hasAttr<WeakAttr>() ||
129 ND->hasAttr<WeakRefAttr>() || ND->isWeakImported());
130
131 Symbols.insert(std::make_pair(
132 ND,
133 MangledSymbol(getMangledNames(ParentDecl).front(),
134 // Type:
135 isa<VarDecl>(ND) ? llvm::ELF::STT_OBJECT
136 : llvm::ELF::STT_FUNC,
137 // Binding:
138 IsWeak ? llvm::ELF::STB_WEAK : llvm::ELF::STB_GLOBAL,
139 getMangledNames(ND))));
140 }
141 return true;
142 }
143
144 void
HandleDecls(const llvm::iterator_range<DeclContext::decl_iterator> & Decls,MangledSymbols & Symbols,int RDO)145 HandleDecls(const llvm::iterator_range<DeclContext::decl_iterator> &Decls,
146 MangledSymbols &Symbols, int RDO) {
147 for (const auto *D : Decls)
148 HandleNamedDecl(dyn_cast<NamedDecl>(D), Symbols, RDO);
149 }
150
HandleTemplateSpecializations(const FunctionTemplateDecl & FTD,MangledSymbols & Symbols,int RDO)151 void HandleTemplateSpecializations(const FunctionTemplateDecl &FTD,
152 MangledSymbols &Symbols, int RDO) {
153 for (const auto *D : FTD.specializations())
154 HandleNamedDecl(dyn_cast<NamedDecl>(D), Symbols, RDO);
155 }
156
HandleTemplateSpecializations(const ClassTemplateDecl & CTD,MangledSymbols & Symbols,int RDO)157 void HandleTemplateSpecializations(const ClassTemplateDecl &CTD,
158 MangledSymbols &Symbols, int RDO) {
159 for (const auto *D : CTD.specializations())
160 HandleNamedDecl(dyn_cast<NamedDecl>(D), Symbols, RDO);
161 }
162
HandleNamedDecl(const NamedDecl * ND,MangledSymbols & Symbols,int RDO)163 bool HandleNamedDecl(const NamedDecl *ND, MangledSymbols &Symbols, int RDO) {
164 if (!ND)
165 return false;
166
167 switch (ND->getKind()) {
168 default:
169 break;
170 case Decl::Kind::Namespace:
171 HandleDecls(cast<NamespaceDecl>(ND)->decls(), Symbols, RDO);
172 return true;
173 case Decl::Kind::CXXRecord:
174 HandleDecls(cast<CXXRecordDecl>(ND)->decls(), Symbols, RDO);
175 return true;
176 case Decl::Kind::ClassTemplateSpecialization:
177 HandleDecls(cast<ClassTemplateSpecializationDecl>(ND)->decls(), Symbols,
178 RDO);
179 return true;
180 case Decl::Kind::ClassTemplate:
181 HandleTemplateSpecializations(*cast<ClassTemplateDecl>(ND), Symbols, RDO);
182 return true;
183 case Decl::Kind::FunctionTemplate:
184 HandleTemplateSpecializations(*cast<FunctionTemplateDecl>(ND), Symbols,
185 RDO);
186 return true;
187 case Decl::Kind::Record:
188 case Decl::Kind::Typedef:
189 case Decl::Kind::Enum:
190 case Decl::Kind::EnumConstant:
191 case Decl::Kind::TemplateTypeParm:
192 case Decl::Kind::NonTypeTemplateParm:
193 case Decl::Kind::CXXConversion:
194 case Decl::Kind::UnresolvedUsingValue:
195 case Decl::Kind::Using:
196 case Decl::Kind::UsingShadow:
197 case Decl::Kind::TypeAliasTemplate:
198 case Decl::Kind::TypeAlias:
199 case Decl::Kind::VarTemplate:
200 case Decl::Kind::VarTemplateSpecialization:
201 case Decl::Kind::UsingDirective:
202 case Decl::Kind::TemplateTemplateParm:
203 case Decl::Kind::ClassTemplatePartialSpecialization:
204 case Decl::Kind::IndirectField:
205 case Decl::Kind::ConstructorUsingShadow:
206 case Decl::Kind::CXXDeductionGuide:
207 case Decl::Kind::NamespaceAlias:
208 case Decl::Kind::UnresolvedUsingTypename:
209 return true;
210 case Decl::Kind::Var: {
211 // Bail on any VarDecl that either has no named symbol.
212 if (!ND->getIdentifier())
213 return true;
214 const auto *VD = cast<VarDecl>(ND);
215 // Bail on any VarDecl that is a dependent or templated type.
216 if (VD->isTemplated() || VD->getType()->isDependentType())
217 return true;
218 if (WriteNamedDecl(ND, Symbols, RDO))
219 return true;
220 break;
221 }
222 case Decl::Kind::ParmVar:
223 case Decl::Kind::CXXMethod:
224 case Decl::Kind::CXXConstructor:
225 case Decl::Kind::CXXDestructor:
226 case Decl::Kind::Function:
227 case Decl::Kind::Field:
228 if (WriteNamedDecl(ND, Symbols, RDO))
229 return true;
230 }
231
232 // While interface stubs are in the development stage, it's probably best to
233 // catch anything that's not a VarDecl or Template/FunctionDecl.
234 Instance.getDiagnostics().Report(diag::err_asm_invalid_type_in_input)
235 << "Expected a function or function template decl.";
236 return false;
237 }
238
239 public:
InterfaceStubFunctionsConsumer(CompilerInstance & Instance,StringRef InFile,StringRef Format)240 InterfaceStubFunctionsConsumer(CompilerInstance &Instance, StringRef InFile,
241 StringRef Format)
242 : Instance(Instance), InFile(InFile), Format(Format) {}
243
HandleTranslationUnit(ASTContext & context)244 void HandleTranslationUnit(ASTContext &context) override {
245 struct Visitor : public RecursiveASTVisitor<Visitor> {
246 bool VisitNamedDecl(NamedDecl *ND) {
247 if (const auto *FD = dyn_cast<FunctionDecl>(ND))
248 if (FD->isLateTemplateParsed()) {
249 LateParsedDecls.insert(FD);
250 return true;
251 }
252
253 if (const auto *VD = dyn_cast<ValueDecl>(ND)) {
254 ValueDecls.insert(VD);
255 return true;
256 }
257
258 NamedDecls.insert(ND);
259 return true;
260 }
261
262 std::set<const NamedDecl *> LateParsedDecls;
263 std::set<NamedDecl *> NamedDecls;
264 std::set<const ValueDecl *> ValueDecls;
265 } v;
266
267 v.TraverseDecl(context.getTranslationUnitDecl());
268
269 MangledSymbols Symbols;
270 auto OS = Instance.createDefaultOutputFile(/*Binary=*/false, InFile, "ifs");
271 if (!OS)
272 return;
273
274 if (Instance.getLangOpts().DelayedTemplateParsing) {
275 clang::Sema &S = Instance.getSema();
276 for (const auto *FD : v.LateParsedDecls) {
277 clang::LateParsedTemplate &LPT =
278 *S.LateParsedTemplateMap.find(cast<FunctionDecl>(FD))->second;
279 S.LateTemplateParser(S.OpaqueParser, LPT);
280 HandleNamedDecl(FD, Symbols, (FromTU | IsLate));
281 }
282 }
283
284 for (const NamedDecl *ND : v.ValueDecls)
285 HandleNamedDecl(ND, Symbols, FromTU);
286 for (const NamedDecl *ND : v.NamedDecls)
287 HandleNamedDecl(ND, Symbols, FromTU);
288
289 auto writeIfsV1 = [this](const llvm::Triple &T,
290 const MangledSymbols &Symbols,
291 const ASTContext &context, StringRef Format,
292 raw_ostream &OS) -> void {
293 OS << "--- !" << Format << "\n";
294 OS << "IfsVersion: 3.0\n";
295 OS << "Target: " << T.str() << "\n";
296 OS << "Symbols:\n";
297 for (const auto &E : Symbols) {
298 const MangledSymbol &Symbol = E.second;
299 for (const auto &Name : Symbol.Names) {
300 OS << " - { Name: \""
301 << (Symbol.ParentName.empty() || Instance.getLangOpts().CPlusPlus
302 ? ""
303 : (Symbol.ParentName + "."))
304 << Name << "\", Type: ";
305 switch (Symbol.Type) {
306 default:
307 llvm_unreachable(
308 "clang -emit-interface-stubs: Unexpected symbol type.");
309 case llvm::ELF::STT_NOTYPE:
310 OS << "NoType";
311 break;
312 case llvm::ELF::STT_OBJECT: {
313 auto VD = cast<ValueDecl>(E.first)->getType();
314 OS << "Object, Size: "
315 << context.getTypeSizeInChars(VD).getQuantity();
316 break;
317 }
318 case llvm::ELF::STT_FUNC:
319 OS << "Func";
320 break;
321 }
322 if (Symbol.Binding == llvm::ELF::STB_WEAK)
323 OS << ", Weak: true";
324 OS << " }\n";
325 }
326 }
327 OS << "...\n";
328 OS.flush();
329 };
330
331 assert(Format == "ifs-v1" && "Unexpected IFS Format.");
332 writeIfsV1(Instance.getTarget().getTriple(), Symbols, context, Format, *OS);
333 }
334 };
335 } // namespace
336
337 std::unique_ptr<ASTConsumer>
CreateASTConsumer(CompilerInstance & CI,StringRef InFile)338 GenerateInterfaceStubsAction::CreateASTConsumer(CompilerInstance &CI,
339 StringRef InFile) {
340 return std::make_unique<InterfaceStubFunctionsConsumer>(CI, InFile, "ifs-v1");
341 }
342