ObjectFilePCHContainerOperations.cpp source code [clang_source_code/lib/CodeGen/ObjectFilePCHContainerOperations.cpp]

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
9	#include "clang/CodeGen/ObjectFilePCHContainerOperations.h"
10	#include "CGDebugInfo.h"
11	#include "CodeGenModule.h"
12	#include "clang/AST/ASTContext.h"
13	#include "clang/AST/DeclObjC.h"
14	#include "clang/AST/Expr.h"
15	#include "clang/AST/RecursiveASTVisitor.h"
16	#include "clang/Basic/CodeGenOptions.h"
17	#include "clang/Basic/Diagnostic.h"
18	#include "clang/Basic/TargetInfo.h"
19	#include "clang/CodeGen/BackendUtil.h"
20	#include "clang/Frontend/CompilerInstance.h"
21	#include "clang/Lex/HeaderSearch.h"
22	#include "clang/Lex/Preprocessor.h"
23	#include "llvm/ADT/StringRef.h"
24	#include "llvm/Bitcode/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/Object/COFF.h"
31	#include "llvm/Object/ObjectFile.h"
32	#include "llvm/Support/Path.h"
33	#include "llvm/Support/TargetRegistry.h"
34	#include <memory>
35	#include <utility>
36
37	using namespace clang;
38
39	#define DEBUG_TYPE "pchcontainer"
40
41	namespace {
42	class PCHContainerGenerator : public ASTConsumer {
43	DiagnosticsEngine &Diags;
44	const std::string MainFileName;
45	const std::string OutputFileName;
46	ASTContext *Ctx;
47	ModuleMap &MMap;
48	const HeaderSearchOptions &HeaderSearchOpts;
49	const PreprocessorOptions &PreprocessorOpts;
50	CodeGenOptions CodeGenOpts;
51	const TargetOptions TargetOpts;
52	const LangOptions LangOpts;
53	std::unique_ptr<llvm::LLVMContext> VMContext;
54	std::unique_ptr<llvm::Module> M;
55	std::unique_ptr<CodeGen::CodeGenModule> Builder;
56	std::unique_ptr<raw_pwrite_stream> OS;
57	std::shared_ptr<PCHBuffer> Buffer;
58
59	/// Visit every type and emit debug info for it.
60	struct DebugTypeVisitor : public RecursiveASTVisitor<DebugTypeVisitor> {
61	clang::CodeGen::CGDebugInfo &DI;
62	ASTContext &Ctx;
63	DebugTypeVisitor(clang::CodeGen::CGDebugInfo &DI, ASTContext &Ctx)
64	: DI(DI), Ctx(Ctx) {}
65
66	/// Determine whether this type can be represented in DWARF.
67	static bool CanRepresent(const Type *Ty) {
68	return !Ty->isDependentType() && !Ty->isUndeducedType();
69	}
70
71	bool VisitImportDecl(ImportDecl *D) {
72	if (!D->getImportedOwningModule())
73	DI.EmitImportDecl(*D);
74	return true;
75	}
76
77	bool VisitTypeDecl(TypeDecl *D) {
78	// TagDecls may be deferred until after all decls have been merged and we
79	// know the complete type. Pure forward declarations will be skipped, but
80	// they don't need to be emitted into the module anyway.
81	if (auto *TD = dyn_cast<TagDecl>(D))
82	if (!TD->isCompleteDefinition())
83	return true;
84
85	QualType QualTy = Ctx.getTypeDeclType(D);
86	if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
87	DI.getOrCreateStandaloneType(QualTy, D->getLocation());
88	return true;
89	}
90
91	bool VisitObjCInterfaceDecl(ObjCInterfaceDecl *D) {
92	QualType QualTy(D->getTypeForDecl(), 0);
93	if (!QualTy.isNull() && CanRepresent(QualTy.getTypePtr()))
94	DI.getOrCreateStandaloneType(QualTy, D->getLocation());
95	return true;
96	}
97
98	bool VisitFunctionDecl(FunctionDecl *D) {
99	if (isa<CXXMethodDecl>(D))
100	// This is not yet supported. Constructing the `this' argument
101	// mandates a CodeGenFunction.
102	return true;
103
104	SmallVector<QualType, 16> ArgTypes;
105	for (auto i : D->parameters())
106	ArgTypes.push_back(i->getType());
107	QualType RetTy = D->getReturnType();
108	QualType FnTy = Ctx.getFunctionType(RetTy, ArgTypes,
109	FunctionProtoType::ExtProtoInfo());
110	if (CanRepresent(FnTy.getTypePtr()))
111	DI.EmitFunctionDecl(D, D->getLocation(), FnTy);
112	return true;
113	}
114
115	bool VisitObjCMethodDecl(ObjCMethodDecl *D) {
116	if (!D->getClassInterface())
117	return true;
118
119	bool selfIsPseudoStrong, selfIsConsumed;
120	SmallVector<QualType, 16> ArgTypes;
121	ArgTypes.push_back(D->getSelfType(Ctx, D->getClassInterface(),
122	selfIsPseudoStrong, selfIsConsumed));
123	ArgTypes.push_back(Ctx.getObjCSelType());
124	for (auto i : D->parameters())
125	ArgTypes.push_back(i->getType());
126	QualType RetTy = D->getReturnType();
127	QualType FnTy = Ctx.getFunctionType(RetTy, ArgTypes,
128	FunctionProtoType::ExtProtoInfo());
129	if (CanRepresent(FnTy.getTypePtr()))
130	DI.EmitFunctionDecl(D, D->getLocation(), FnTy);
131	return true;
132	}
133	};
134
135	public:
136	PCHContainerGenerator(CompilerInstance &CI, const std::string &MainFileName,
137	const std::string &OutputFileName,
138	std::unique_ptr<raw_pwrite_stream> OS,
139	std::shared_ptr<PCHBuffer> Buffer)
140	: Diags(CI.getDiagnostics()), MainFileName(MainFileName),
141	OutputFileName(OutputFileName), Ctx(nullptr),
142	MMap(CI.getPreprocessor().getHeaderSearchInfo().getModuleMap()),
143	HeaderSearchOpts(CI.getHeaderSearchOpts()),
144	PreprocessorOpts(CI.getPreprocessorOpts()),
145	TargetOpts(CI.getTargetOpts()), LangOpts(CI.getLangOpts()),
146	OS(std::move(OS)), Buffer(std::move(Buffer)) {
147	// The debug info output isn't affected by CodeModel and
148	// ThreadModel, but the backend expects them to be nonempty.
149	CodeGenOpts.CodeModel = "default";
150	CodeGenOpts.ThreadModel = "single";
151	CodeGenOpts.DebugTypeExtRefs = true;
152	// When building a module MainFileName is the name of the modulemap file.
153	CodeGenOpts.MainFileName =
154	LangOpts.CurrentModule.empty() ? MainFileName : LangOpts.CurrentModule;
155	CodeGenOpts.setDebugInfo(codegenoptions::FullDebugInfo);
156	CodeGenOpts.setDebuggerTuning(CI.getCodeGenOpts().getDebuggerTuning());
157	CodeGenOpts.DebugPrefixMap =
158	CI.getInvocation().getCodeGenOpts().DebugPrefixMap;
159	}
160
161	~PCHContainerGenerator() override = default;
162
163	void Initialize(ASTContext &Context) override {
164	(0) . __assert_fail ("!Ctx && \"initialized multiple times\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp", 164, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(!Ctx && "initialized multiple times");
165
166	Ctx = &Context;
167	VMContext.reset(new llvm::LLVMContext());
168	M.reset(new llvm::Module(MainFileName, *VMContext));
169	M->setDataLayout(Ctx->getTargetInfo().getDataLayout());
170	Builder.reset(new CodeGen::CodeGenModule(
171	Ctx, HeaderSearchOpts, PreprocessorOpts, CodeGenOpts, M, Diags));
172
173	// Prepare CGDebugInfo to emit debug info for a clang module.
174	auto *DI = Builder->getModuleDebugInfo();
175	StringRef ModuleName = llvm::sys::path::filename(MainFileName);
176	DI->setPCHDescriptor({ModuleName, "", OutputFileName,
177	ASTFileSignature{{{~0U, ~0U, ~0U, ~0U, ~1U}}}});
178	DI->setModuleMap(MMap);
179	}
180
181	bool HandleTopLevelDecl(DeclGroupRef D) override {
182	if (Diags.hasErrorOccurred())
183	return true;
184
185	// Collect debug info for all decls in this group.
186	for (auto *I : D)
187	if (!I->isFromASTFile()) {
188	DebugTypeVisitor DTV(Builder->getModuleDebugInfo(), Ctx);
189	DTV.TraverseDecl(I);
190	}
191	return true;
192	}
193
194	void HandleTopLevelDeclInObjCContainer(DeclGroupRef D) override {
195	HandleTopLevelDecl(D);
196	}
197
198	void HandleTagDeclDefinition(TagDecl *D) override {
199	if (Diags.hasErrorOccurred())
200	return;
201
202	if (D->isFromASTFile())
203	return;
204
205	// Anonymous tag decls are deferred until we are building their declcontext.
206	if (D->getName().empty())
207	return;
208
209	// Defer tag decls until their declcontext is complete.
210	auto *DeclCtx = D->getDeclContext();
211	while (DeclCtx) {
212	if (auto *D = dyn_cast<TagDecl>(DeclCtx))
213	if (!D->isCompleteDefinition())
214	return;
215	DeclCtx = DeclCtx->getParent();
216	}
217
218	DebugTypeVisitor DTV(Builder->getModuleDebugInfo(), Ctx);
219	DTV.TraverseDecl(D);
220	Builder->UpdateCompletedType(D);
221	}
222
223	void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
224	if (Diags.hasErrorOccurred())
225	return;
226
227	if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
228	Builder->getModuleDebugInfo()->completeRequiredType(RD);
229	}
230
231	void HandleImplicitImportDecl(ImportDecl *D) override {
232	if (!D->getImportedOwningModule())
233	Builder->getModuleDebugInfo()->EmitImportDecl(*D);
234	}
235
236	/// Emit a container holding the serialized AST.
237	void HandleTranslationUnit(ASTContext &Ctx) override {
238	assert(M && VMContext && Builder);
239	// Delete these on function exit.
240	std::unique_ptr<llvm::LLVMContext> VMContext = std::move(this->VMContext);
241	std::unique_ptr<llvm::Module> M = std::move(this->M);
242	std::unique_ptr<CodeGen::CodeGenModule> Builder = std::move(this->Builder);
243
244	if (Diags.hasErrorOccurred())
245	return;
246
247	M->setTargetTriple(Ctx.getTargetInfo().getTriple().getTriple());
248	M->setDataLayout(Ctx.getTargetInfo().getDataLayout());
249
250	// PCH files don't have a signature field in the control block,
251	// but LLVM detects DWO CUs by looking for a non-zero DWO id.
252	// We use the lower 64 bits for debug info.
253	uint64_t Signature =
254	Buffer->Signature
255	? (uint64_t)Buffer->Signature[1] << 32 \| Buffer->Signature[0]
256	: ~1ULL;
257	Builder->getModuleDebugInfo()->setDwoId(Signature);
258
259	// Finalize the Builder.
260	if (Builder)
261	Builder->Release();
262
263	// Ensure the target exists.
264	std::string Error;
265	auto Triple = Ctx.getTargetInfo().getTriple();
266	if (!llvm::TargetRegistry::lookupTarget(Triple.getTriple(), Error))
267	llvm::report_fatal_error(Error);
268
269	// Emit the serialized Clang AST into its own section.
270	(0) . __assert_fail ("Buffer->IsComplete && \"serialization did not complete\"", "/home/seafit/code_projects/clang_source/clang/lib/CodeGen/ObjectFilePCHContainerOperations.cpp", 270, __PRETTY_FUNCTION__))" file_link="../../../include/assert.h.html#88" macro="true">assert(Buffer->IsComplete && "serialization did not complete");
271	auto &SerializedAST = Buffer->Data;
272	auto Size = SerializedAST.size();
273	auto Int8Ty = llvm::Type::getInt8Ty(*VMContext);
274	auto *Ty = llvm::ArrayType::get(Int8Ty, Size);
275	auto *Data = llvm::ConstantDataArray::getString(
276	*VMContext, StringRef(SerializedAST.data(), Size),
277	/AddNull=/false);
278	auto *ASTSym = new llvm::GlobalVariable(
279	M, Ty, /constant*/ true, llvm::GlobalVariable::InternalLinkage, Data,
280	"__clang_ast");
281	// The on-disk hashtable needs to be aligned.
282	ASTSym->setAlignment(8);
283
284	// Mach-O also needs a segment name.
285	if (Triple.isOSBinFormatMachO())
286	ASTSym->setSection("__CLANG,__clangast");
287	// COFF has an eight character length limit.
288	else if (Triple.isOSBinFormatCOFF())
289	ASTSym->setSection("clangast");
290	else
291	ASTSym->setSection("__clangast");
292
293	LLVM_DEBUG({
294	// Print the IR for the PCH container to the debug output.
295	llvm::SmallString<0> Buffer;
296	clang::EmitBackendOutput(
297	Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts, LangOpts,
298	Ctx.getTargetInfo().getDataLayout(), M.get(),
299	BackendAction::Backend_EmitLL,
300	llvm::make_unique<llvm::raw_svector_ostream>(Buffer));
301	llvm::dbgs() << Buffer;
302	});
303
304	// Use the LLVM backend to emit the pch container.
305	clang::EmitBackendOutput(Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts,
306	LangOpts, Ctx.getTargetInfo().getDataLayout(),
307	M.get(), BackendAction::Backend_EmitObj,
308	std::move(OS));
309
310	// Free the memory for the temporary buffer.
311	llvm::SmallVector<char, 0> Empty;
312	SerializedAST = std::move(Empty);
313	}
314	};
315
316	} // anonymous namespace
317
318	std::unique_ptr<ASTConsumer>
319	ObjectFilePCHContainerWriter::CreatePCHContainerGenerator(
320	CompilerInstance &CI, const std::string &MainFileName,
321	const std::string &OutputFileName,
322	std::unique_ptr<llvm::raw_pwrite_stream> OS,
323	std::shared_ptr<PCHBuffer> Buffer) const {
324	return llvm::make_unique<PCHContainerGenerator>(
325	CI, MainFileName, OutputFileName, std::move(OS), Buffer);
326	}
327
328	StringRef
329	ObjectFilePCHContainerReader::ExtractPCH(llvm::MemoryBufferRef Buffer) const {
330	StringRef PCH;
331	auto OFOrErr = llvm::object::ObjectFile::createObjectFile(Buffer);
332	if (OFOrErr) {
333	auto &OF = OFOrErr.get();
334	bool IsCOFF = isa<llvm::object::COFFObjectFile>(*OF);
335	// Find the clang AST section in the container.
336	for (auto &Section : OF->sections()) {
337	StringRef Name;
338	Section.getName(Name);
339	if ((!IsCOFF && Name == "__clangast") \|\| (IsCOFF && Name == "clangast")) {
340	Section.getContents(PCH);
341	return PCH;
342	}
343	}
344	}
345	handleAllErrors(OFOrErr.takeError(), [&](const llvm::ErrorInfoBase &EIB) {
346	if (EIB.convertToErrorCode() ==
347	llvm::object::object_error::invalid_file_type)
348	// As a fallback, treat the buffer as a raw AST.
349	PCH = Buffer.getBuffer();
350	else
351	EIB.log(llvm::errs());
352	});
353	return PCH;
354	}
355

clang::ObjectFilePCHContainerWriter::CreatePCHContainerGenerator

clang::ObjectFilePCHContainerReader::ExtractPCH

Clang Project