clang 19.0.0git
ObjectFilePCHContainerOperations.cpp
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1//===--- ObjectFilePCHContainerOperations.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
10#include "CGDebugInfo.h"
11#include "CodeGenModule.h"
13#include "clang/AST/DeclObjC.h"
14#include "clang/AST/Expr.h"
23#include "llvm/ADT/StringRef.h"
24#include "llvm/Bitstream/BitstreamReader.h"
25#include "llvm/DebugInfo/DWARF/DWARFContext.h"
26#include "llvm/IR/Constants.h"
27#include "llvm/IR/DataLayout.h"
28#include "llvm/IR/LLVMContext.h"
29#include "llvm/IR/Module.h"
30#include "llvm/MC/TargetRegistry.h"
31#include "llvm/Object/COFF.h"
32#include "llvm/Object/ObjectFile.h"
33#include "llvm/Support/Path.h"
34#include <memory>
35#include <utility>
36
37using namespace clang;
38
39#define DEBUG_TYPE "pchcontainer"
40
41namespace {
42class PCHContainerGenerator : public ASTConsumer {
43 DiagnosticsEngine &Diags;
44 const std::string MainFileName;
45 const std::string OutputFileName;
46 ASTContext *Ctx;
47 ModuleMap &MMap;
49 const HeaderSearchOptions &HeaderSearchOpts;
50 const PreprocessorOptions &PreprocessorOpts;
51 CodeGenOptions CodeGenOpts;
52 const TargetOptions TargetOpts;
53 LangOptions LangOpts;
54 std::unique_ptr<llvm::LLVMContext> VMContext;
55 std::unique_ptr<llvm::Module> M;
56 std::unique_ptr<CodeGen::CodeGenModule> Builder;
57 std::unique_ptr<raw_pwrite_stream> OS;
58 std::shared_ptr<PCHBuffer> Buffer;
59
60 /// Visit every type and emit debug info for it.
61 struct DebugTypeVisitor : public RecursiveASTVisitor<DebugTypeVisitor> {
63 ASTContext &Ctx;
64 DebugTypeVisitor(clang::CodeGen::CGDebugInfo &DI, ASTContext &Ctx)
65 : DI(DI), Ctx(Ctx) {}
66
67 /// Determine whether this type can be represented in DWARF.
68 static bool CanRepresent(const Type *Ty) {
69 return !Ty->isDependentType() && !Ty->isUndeducedType();
70 }
71
72 bool VisitImportDecl(ImportDecl *D) {
74 DI.EmitImportDecl(*D);
75 return true;
76 }
77
78 bool VisitTypeDecl(TypeDecl *D) {
79 // TagDecls may be deferred until after all decls have been merged and we
80 // know the complete type. Pure forward declarations will be skipped, but
81 // they don't need to be emitted into the module anyway.
82 if (auto *TD = dyn_cast<TagDecl>(D))
83 if (!TD->isCompleteDefinition())
84 return true;
85
86 QualType QualTy = Ctx.getTypeDeclType(D);
87 if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
89 return true;
90 }
91
92 bool VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
93 QualType QualTy(D->getTypeForDecl(), 0);
94 if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
96 return true;
97 }
98
99 bool VisitFunctionDecl(FunctionDecl *D) {
100 // Skip deduction guides.
101 if (isa<CXXDeductionGuideDecl>(D))
102 return true;
103
104 if (isa<CXXMethodDecl>(D))
105 // This is not yet supported. Constructing the `this' argument
106 // mandates a CodeGenFunction.
107 return true;
108
110 for (auto *i : D->parameters())
111 ArgTypes.push_back(i->getType());
112 QualType RetTy = D->getReturnType();
113 QualType FnTy = Ctx.getFunctionType(RetTy, ArgTypes,
115 if (CanRepresent(FnTy.getTypePtr()))
116 DI.EmitFunctionDecl(D, D->getLocation(), FnTy);
117 return true;
118 }
119
120 bool VisitObjCMethodDecl(ObjCMethodDecl *D) {
121 if (!D->getClassInterface())
122 return true;
123
124 bool selfIsPseudoStrong, selfIsConsumed;
126 ArgTypes.push_back(D->getSelfType(Ctx, D->getClassInterface(),
127 selfIsPseudoStrong, selfIsConsumed));
128 ArgTypes.push_back(Ctx.getObjCSelType());
129 for (auto *i : D->parameters())
130 ArgTypes.push_back(i->getType());
131 QualType RetTy = D->getReturnType();
132 QualType FnTy = Ctx.getFunctionType(RetTy, ArgTypes,
134 if (CanRepresent(FnTy.getTypePtr()))
135 DI.EmitFunctionDecl(D, D->getLocation(), FnTy);
136 return true;
137 }
138 };
139
140public:
141 PCHContainerGenerator(CompilerInstance &CI, const std::string &MainFileName,
142 const std::string &OutputFileName,
143 std::unique_ptr<raw_pwrite_stream> OS,
144 std::shared_ptr<PCHBuffer> Buffer)
145 : Diags(CI.getDiagnostics()), MainFileName(MainFileName),
146 OutputFileName(OutputFileName), Ctx(nullptr),
148 FS(&CI.getVirtualFileSystem()),
149 HeaderSearchOpts(CI.getHeaderSearchOpts()),
150 PreprocessorOpts(CI.getPreprocessorOpts()),
151 TargetOpts(CI.getTargetOpts()), LangOpts(CI.getLangOpts()),
152 OS(std::move(OS)), Buffer(std::move(Buffer)) {
153 // The debug info output isn't affected by CodeModel and
154 // ThreadModel, but the backend expects them to be nonempty.
155 CodeGenOpts.CodeModel = "default";
156 LangOpts.setThreadModel(LangOptions::ThreadModelKind::Single);
157 CodeGenOpts.DebugTypeExtRefs = true;
158 // When building a module MainFileName is the name of the modulemap file.
159 CodeGenOpts.MainFileName =
160 LangOpts.CurrentModule.empty() ? MainFileName : LangOpts.CurrentModule;
161 CodeGenOpts.setDebugInfo(llvm::codegenoptions::FullDebugInfo);
162 CodeGenOpts.setDebuggerTuning(CI.getCodeGenOpts().getDebuggerTuning());
163 CodeGenOpts.DwarfVersion = CI.getCodeGenOpts().DwarfVersion;
164 CodeGenOpts.DebugCompilationDir =
166 CodeGenOpts.DebugPrefixMap =
168 CodeGenOpts.DebugStrictDwarf = CI.getCodeGenOpts().DebugStrictDwarf;
169 }
170
171 ~PCHContainerGenerator() override = default;
172
173 void Initialize(ASTContext &Context) override {
174 assert(!Ctx && "initialized multiple times");
175
176 Ctx = &Context;
177 VMContext.reset(new llvm::LLVMContext());
178 M.reset(new llvm::Module(MainFileName, *VMContext));
179 M->setDataLayout(Ctx->getTargetInfo().getDataLayoutString());
180 Builder.reset(new CodeGen::CodeGenModule(
181 *Ctx, FS, HeaderSearchOpts, PreprocessorOpts, CodeGenOpts, *M, Diags));
182
183 // Prepare CGDebugInfo to emit debug info for a clang module.
184 auto *DI = Builder->getModuleDebugInfo();
185 StringRef ModuleName = llvm::sys::path::filename(MainFileName);
186 DI->setPCHDescriptor(
187 {ModuleName, "", OutputFileName, ASTFileSignature::createDISentinel()});
188 DI->setModuleMap(MMap);
189 }
190
191 bool HandleTopLevelDecl(DeclGroupRef D) override {
192 if (Diags.hasErrorOccurred())
193 return true;
194
195 // Collect debug info for all decls in this group.
196 for (auto *I : D)
197 if (!I->isFromASTFile()) {
198 DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);
199 DTV.TraverseDecl(I);
200 }
201 return true;
202 }
203
206 }
207
208 void HandleTagDeclDefinition(TagDecl *D) override {
209 if (Diags.hasErrorOccurred())
210 return;
211
212 if (D->isFromASTFile())
213 return;
214
215 // Anonymous tag decls are deferred until we are building their declcontext.
216 if (D->getName().empty())
217 return;
218
219 // Defer tag decls until their declcontext is complete.
220 auto *DeclCtx = D->getDeclContext();
221 while (DeclCtx) {
222 if (auto *D = dyn_cast<TagDecl>(DeclCtx))
223 if (!D->isCompleteDefinition())
224 return;
225 DeclCtx = DeclCtx->getParent();
226 }
227
228 DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);
229 DTV.TraverseDecl(D);
230 Builder->UpdateCompletedType(D);
231 }
232
233 void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
234 if (Diags.hasErrorOccurred())
235 return;
236
237 if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
238 Builder->getModuleDebugInfo()->completeRequiredType(RD);
239 }
240
241 void HandleImplicitImportDecl(ImportDecl *D) override {
242 if (!D->getImportedOwningModule())
243 Builder->getModuleDebugInfo()->EmitImportDecl(*D);
244 }
245
246 /// Emit a container holding the serialized AST.
247 void HandleTranslationUnit(ASTContext &Ctx) override {
248 assert(M && VMContext && Builder);
249 // Delete these on function exit.
250 std::unique_ptr<llvm::LLVMContext> VMContext = std::move(this->VMContext);
251 std::unique_ptr<llvm::Module> M = std::move(this->M);
252 std::unique_ptr<CodeGen::CodeGenModule> Builder = std::move(this->Builder);
253
254 if (Diags.hasErrorOccurred())
255 return;
256
257 M->setTargetTriple(Ctx.getTargetInfo().getTriple().getTriple());
258 M->setDataLayout(Ctx.getTargetInfo().getDataLayoutString());
259
260 // PCH files don't have a signature field in the control block,
261 // but LLVM detects DWO CUs by looking for a non-zero DWO id.
262 // We use the lower 64 bits for debug info.
263
264 uint64_t Signature =
265 Buffer->Signature ? Buffer->Signature.truncatedValue() : ~1ULL;
266
267 Builder->getModuleDebugInfo()->setDwoId(Signature);
268
269 // Finalize the Builder.
270 if (Builder)
271 Builder->Release();
272
273 // Ensure the target exists.
274 std::string Error;
275 auto Triple = Ctx.getTargetInfo().getTriple();
276 if (!llvm::TargetRegistry::lookupTarget(Triple.getTriple(), Error))
277 llvm::report_fatal_error(llvm::Twine(Error));
278
279 // Emit the serialized Clang AST into its own section.
280 assert(Buffer->IsComplete && "serialization did not complete");
281 auto &SerializedAST = Buffer->Data;
282 auto Size = SerializedAST.size();
283
284 if (Triple.isOSBinFormatWasm()) {
285 // Emit __clangast in custom section instead of named data segment
286 // to find it while iterating sections.
287 // This could be avoided if all data segements (the wasm sense) were
288 // represented as their own sections (in the llvm sense).
289 // TODO: https://github.com/WebAssembly/tool-conventions/issues/138
290 llvm::NamedMDNode *MD =
291 M->getOrInsertNamedMetadata("wasm.custom_sections");
292 llvm::Metadata *Ops[2] = {
293 llvm::MDString::get(*VMContext, "__clangast"),
294 llvm::MDString::get(*VMContext,
295 StringRef(SerializedAST.data(), Size))};
296 auto *NameAndContent = llvm::MDTuple::get(*VMContext, Ops);
297 MD->addOperand(NameAndContent);
298 } else {
299 auto Int8Ty = llvm::Type::getInt8Ty(*VMContext);
300 auto *Ty = llvm::ArrayType::get(Int8Ty, Size);
301 auto *Data = llvm::ConstantDataArray::getString(
302 *VMContext, StringRef(SerializedAST.data(), Size),
303 /*AddNull=*/false);
304 auto *ASTSym = new llvm::GlobalVariable(
305 *M, Ty, /*constant*/ true, llvm::GlobalVariable::InternalLinkage,
306 Data, "__clang_ast");
307 // The on-disk hashtable needs to be aligned.
308 ASTSym->setAlignment(llvm::Align(8));
309
310 // Mach-O also needs a segment name.
311 if (Triple.isOSBinFormatMachO())
312 ASTSym->setSection("__CLANG,__clangast");
313 // COFF has an eight character length limit.
314 else if (Triple.isOSBinFormatCOFF())
315 ASTSym->setSection("clangast");
316 else
317 ASTSym->setSection("__clangast");
318 }
319
320 LLVM_DEBUG({
321 // Print the IR for the PCH container to the debug output.
324 Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts, LangOpts,
325 Ctx.getTargetInfo().getDataLayoutString(), M.get(),
326 BackendAction::Backend_EmitLL, FS,
327 std::make_unique<llvm::raw_svector_ostream>(Buffer));
328 llvm::dbgs() << Buffer;
329 });
330
331 // Use the LLVM backend to emit the pch container.
332 clang::EmitBackendOutput(Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts,
333 LangOpts,
334 Ctx.getTargetInfo().getDataLayoutString(), M.get(),
335 BackendAction::Backend_EmitObj, FS, std::move(OS));
336
337 // Free the memory for the temporary buffer.
339 SerializedAST = std::move(Empty);
340 }
341};
342
343} // anonymous namespace
344
345std::unique_ptr<ASTConsumer>
346ObjectFilePCHContainerWriter::CreatePCHContainerGenerator(
347 CompilerInstance &CI, const std::string &MainFileName,
348 const std::string &OutputFileName,
349 std::unique_ptr<llvm::raw_pwrite_stream> OS,
350 std::shared_ptr<PCHBuffer> Buffer) const {
351 return std::make_unique<PCHContainerGenerator>(
352 CI, MainFileName, OutputFileName, std::move(OS), Buffer);
353}
354
355ArrayRef<StringRef> ObjectFilePCHContainerReader::getFormats() const {
356 static StringRef Formats[] = {"obj", "raw"};
357 return Formats;
358}
359
360StringRef
361ObjectFilePCHContainerReader::ExtractPCH(llvm::MemoryBufferRef Buffer) const {
362 StringRef PCH;
363 auto OFOrErr = llvm::object::ObjectFile::createObjectFile(Buffer);
364 if (OFOrErr) {
365 auto &OF = OFOrErr.get();
366 bool IsCOFF = isa<llvm::object::COFFObjectFile>(*OF);
367 // Find the clang AST section in the container.
368 for (auto &Section : OF->sections()) {
369 StringRef Name;
370 if (Expected<StringRef> NameOrErr = Section.getName())
371 Name = *NameOrErr;
372 else
373 consumeError(NameOrErr.takeError());
374
375 if ((!IsCOFF && Name == "__clangast") || (IsCOFF && Name == "clangast")) {
376 if (Expected<StringRef> E = Section.getContents())
377 return *E;
378 else {
379 handleAllErrors(E.takeError(), [&](const llvm::ErrorInfoBase &EIB) {
380 EIB.log(llvm::errs());
381 });
382 return "";
383 }
384 }
385 }
386 }
387 handleAllErrors(OFOrErr.takeError(), [&](const llvm::ErrorInfoBase &EIB) {
388 if (EIB.convertToErrorCode() ==
389 llvm::object::object_error::invalid_file_type)
390 // As a fallback, treat the buffer as a raw AST.
391 PCH = Buffer.getBuffer();
392 else
393 EIB.log(llvm::errs());
394 });
395 return PCH;
396}
Defines the clang::ASTContext interface.
Defines the Diagnostic-related interfaces.
Defines the clang::Preprocessor interface.
const char * Data
ASTConsumer - This is an abstract interface that should be implemented by clients that read ASTs.
Definition: ASTConsumer.h:33
virtual void HandleTagDeclDefinition(TagDecl *D)
HandleTagDeclDefinition - This callback is invoked each time a TagDecl (e.g.
Definition: ASTConsumer.h:72
virtual void HandleTranslationUnit(ASTContext &Ctx)
HandleTranslationUnit - This method is called when the ASTs for entire translation unit have been par...
Definition: ASTConsumer.h:66
virtual void HandleTagDeclRequiredDefinition(const TagDecl *D)
This callback is invoked the first time each TagDecl is required to be complete.
Definition: ASTConsumer.h:76
virtual void HandleTopLevelDeclInObjCContainer(DeclGroupRef D)
Handle the specified top-level declaration that occurred inside and ObjC container.
Definition: ASTConsumer.cpp:26
virtual bool HandleTopLevelDecl(DeclGroupRef D)
HandleTopLevelDecl - Handle the specified top-level declaration.
Definition: ASTConsumer.cpp:18
virtual void Initialize(ASTContext &Context)
Initialize - This is called to initialize the consumer, providing the ASTContext.
Definition: ASTConsumer.h:47
virtual void HandleImplicitImportDecl(ImportDecl *D)
Handle an ImportDecl that was implicitly created due to an inclusion directive.
Definition: ASTConsumer.cpp:28
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:182
QualType getTypeDeclType(const TypeDecl *Decl, const TypeDecl *PrevDecl=nullptr) const
Return the unique reference to the type for the specified type declaration.
Definition: ASTContext.h:1575
QualType getObjCSelType() const
Retrieve the type that corresponds to the predefined Objective-C 'SEL' type.
Definition: ASTContext.h:2058
QualType getFunctionType(QualType ResultTy, ArrayRef< QualType > Args, const FunctionProtoType::ExtProtoInfo &EPI) const
Return a normal function type with a typed argument list.
Definition: ASTContext.h:1553
const TargetInfo & getTargetInfo() const
Definition: ASTContext.h:752
CodeGenOptions - Track various options which control how the code is optimized and passed to the back...
llvm::SmallVector< std::pair< std::string, std::string >, 0 > DebugPrefixMap
std::string CodeModel
The code model to use (-mcmodel).
std::string DebugCompilationDir
The string to embed in debug information as the current working directory.
std::string MainFileName
The user provided name for the "main file", if non-empty.
This class gathers all debug information during compilation and is responsible for emitting to llvm g...
Definition: CGDebugInfo.h:55
llvm::DIType * getOrCreateStandaloneType(QualType Ty, SourceLocation Loc)
Emit standalone debug info for a type.
void EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc, QualType FnType, llvm::Function *Fn=nullptr)
Emit debug info for a function declaration.
void EmitImportDecl(const ImportDecl &ID)
Emit an @import declaration.
This class organizes the cross-function state that is used while generating LLVM code.
CompilerInstance - Helper class for managing a single instance of the Clang compiler.
DiagnosticsEngine & getDiagnostics() const
Get the current diagnostics engine.
Preprocessor & getPreprocessor() const
Return the current preprocessor.
TargetOptions & getTargetOpts()
HeaderSearchOptions & getHeaderSearchOpts()
CompilerInvocation & getInvocation()
PreprocessorOptions & getPreprocessorOpts()
llvm::vfs::FileSystem & getVirtualFileSystem() const
LangOptions & getLangOpts()
CodeGenOptions & getCodeGenOpts()
CodeGenOptions & getCodeGenOpts()
DeclContext * getParent()
getParent - Returns the containing DeclContext.
Definition: DeclBase.h:2066
Module * getImportedOwningModule() const
Get the imported owning module, if this decl is from an imported (non-local) module.
Definition: DeclBase.h:803
bool isFromASTFile() const
Determine whether this declaration came from an AST file (such as a precompiled header or module) rat...
Definition: DeclBase.h:776
SourceLocation getLocation() const
Definition: DeclBase.h:444
DeclContext * getDeclContext()
Definition: DeclBase.h:453
Concrete class used by the front-end to report problems and issues.
Definition: Diagnostic.h:192
bool hasErrorOccurred() const
Definition: Diagnostic.h:843
Represents a function declaration or definition.
Definition: Decl.h:1959
QualType getReturnType() const
Definition: Decl.h:2722
ArrayRef< ParmVarDecl * > parameters() const
Definition: Decl.h:2651
HeaderSearchOptions - Helper class for storing options related to the initialization of the HeaderSea...
ModuleMap & getModuleMap()
Retrieve the module map.
Definition: HeaderSearch.h:812
Describes a module import declaration, which makes the contents of the named module visible in the cu...
Definition: Decl.h:4760
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:418
std::string CurrentModule
The name of the current module, of which the main source file is a part.
Definition: LangOptions.h:473
StringRef getName() const
Get the name of identifier for this declaration as a StringRef.
Definition: Decl.h:276
Represents an ObjC class declaration.
Definition: DeclObjC.h:1150
const Type * getTypeForDecl() const
Definition: DeclObjC.h:1914
ObjCMethodDecl - Represents an instance or class method declaration.
Definition: DeclObjC.h:140
ArrayRef< ParmVarDecl * > parameters() const
Definition: DeclObjC.h:373
QualType getSelfType(ASTContext &Context, const ObjCInterfaceDecl *OID, bool &selfIsPseudoStrong, bool &selfIsConsumed) const
Definition: DeclObjC.cpp:1145
QualType getReturnType() const
Definition: DeclObjC.h:329
ObjCInterfaceDecl * getClassInterface()
Definition: DeclObjC.cpp:1211
PreprocessorOptions - This class is used for passing the various options used in preprocessor initial...
HeaderSearch & getHeaderSearchInfo() const
A (possibly-)qualified type.
Definition: Type.h:737
bool isNull() const
Return true if this QualType doesn't point to a type yet.
Definition: Type.h:804
const Type * getTypePtr() const
Retrieves a pointer to the underlying (unqualified) type.
Definition: Type.h:6901
Represents a struct/union/class.
Definition: Decl.h:4133
A class that does preorder or postorder depth-first traversal on the entire Clang AST and visits each...
Represents the declaration of a struct/union/class/enum.
Definition: Decl.h:3549
bool isCompleteDefinition() const
Return true if this decl has its body fully specified.
Definition: Decl.h:3652
const llvm::Triple & getTriple() const
Returns the target triple of the primary target.
Definition: TargetInfo.h:1219
const char * getDataLayoutString() const
Definition: TargetInfo.h:1228
Options for controlling the target.
Definition: TargetOptions.h:26
Represents a declaration of a type.
Definition: Decl.h:3357
The base class of the type hierarchy.
Definition: Type.h:1606
bool isDependentType() const
Whether this type is a dependent type, meaning that its definition somehow depends on a template para...
Definition: Type.h:2419
bool isUndeducedType() const
Determine whether this type is an undeduced type, meaning that it somehow involves a C++11 'auto' typ...
Definition: Type.h:7568
Defines the clang::TargetInfo interface.
The JSON file list parser is used to communicate input to InstallAPI.
void EmitBackendOutput(DiagnosticsEngine &Diags, const HeaderSearchOptions &, const CodeGenOptions &CGOpts, const TargetOptions &TOpts, const LangOptions &LOpts, StringRef TDesc, llvm::Module *M, BackendAction Action, llvm::IntrusiveRefCntPtr< llvm::vfs::FileSystem > VFS, std::unique_ptr< raw_pwrite_stream > OS, BackendConsumer *BC=nullptr)
@ PCH
Disable validation for a precompiled header and the modules it depends on.
static ASTFileSignature createDISentinel()
Definition: Module.h:79
Extra information about a function prototype.
Definition: Type.h:4277