[clang-ifs] Clang Interface Stubs, first version (second landing attempt).
This change reverts r363649; effectively re-landing r363626. At this point
clang::Index::CodegenNameGeneratorImpl has been refactored into
clang::AST::ASTNameGenerator. This makes it so that the previous circular link
dependency no longer exists, fixing the previous share lib
(-DBUILD_SHARED_LIBS=ON) build issue which was the reason for r363649.
Clang interface stubs (previously referred to as clang-ifsos) is a new frontend
action in clang that allows the generation of stub files that contain mangled
name info that can be used to produce a stub library. These stub libraries can
be useful for breaking up build dependencies and controlling access to a
library's internal symbols. Generation of these stubs can be invoked by:
clang -fvisibility=<visibility> -emit-interface-stubs \
-interface-stub-version=<interface format>
Notice that -fvisibility (along with use of visibility attributes) can be used
to control what symbols get generated. Currently the interface format is
experimental but there are a wide range of possibilities here.
Currently clang-ifs produces .ifs files that can be thought of as analogous to
object (.o) files, but just for the mangled symbol info. In a subsequent patch
I intend to add support for merging the .ifs files into one .ifs/.ifso file
that can be the input to something like llvm-elfabi to produce something like a
.so file or .dll (but without any of the code, just symbols).
Differential Revision: https://reviews.llvm.org/D60974
llvm-svn: 363948
diff --git a/clang/lib/Frontend/InterfaceStubFunctionsConsumer.cpp b/clang/lib/Frontend/InterfaceStubFunctionsConsumer.cpp
new file mode 100644
index 0000000..fbba9ae
--- /dev/null
+++ b/clang/lib/Frontend/InterfaceStubFunctionsConsumer.cpp
@@ -0,0 +1,378 @@
+//===--- InterfaceStubFunctionsConsumer.cpp -------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/Mangle.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/FrontendActions.h"
+#include "clang/Sema/TemplateInstCallback.h"
+#include "llvm/BinaryFormat/ELF.h"
+
+using namespace clang;
+
+class InterfaceStubFunctionsConsumer : public ASTConsumer {
+ CompilerInstance &Instance;
+ StringRef InFile;
+ StringRef Format;
+ std::set<std::string> ParsedTemplates;
+
+ enum RootDeclOrigin { TopLevel = 0, FromTU = 1, IsLate = 2 };
+ struct MangledSymbol {
+ std::string ParentName;
+ uint8_t Type;
+ uint8_t Binding;
+ std::vector<std::string> Names;
+ MangledSymbol() = delete;
+
+ MangledSymbol(const std::string &ParentName, uint8_t Type, uint8_t Binding,
+ std::vector<std::string> Names)
+ : ParentName(ParentName), Type(Type), Binding(Binding), Names(Names) {}
+ };
+ using MangledSymbols = std::map<const NamedDecl *, MangledSymbol>;
+
+ bool WriteNamedDecl(const NamedDecl *ND, MangledSymbols &Symbols, int RDO) {
+ // Here we filter out anything that's not set to DefaultVisibility.
+ // DefaultVisibility is set on a decl when -fvisibility is not specified on
+ // the command line (or specified as default) and the decl does not have
+ // __attribute__((visibility("hidden"))) set or when the command line
+ // argument is set to hidden but the decl explicitly has
+ // __attribute__((visibility ("default"))) set. We do this so that the user
+ // can have fine grain control of what they want to expose in the stub.
+ auto isVisible = [](const NamedDecl *ND) -> bool {
+ return ND->getVisibility() == DefaultVisibility;
+ };
+
+ auto ignoreDecl = [this, isVisible](const NamedDecl *ND) -> bool {
+ if (!isVisible(ND))
+ return true;
+
+ if (const VarDecl *VD = dyn_cast<VarDecl>(ND))
+ if ((VD->getStorageClass() == StorageClass::SC_Extern) ||
+ (VD->getStorageClass() == StorageClass::SC_Static &&
+ VD->getParentFunctionOrMethod() == nullptr))
+ return true;
+
+ if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) {
+ if (FD->isInlined() && !isa<CXXMethodDecl>(FD) &&
+ !Instance.getLangOpts().GNUInline)
+ return true;
+ if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
+ if (const auto *RC = dyn_cast<CXXRecordDecl>(MD->getParent()))
+ if (isa<ClassTemplateDecl>(RC->getParent()) || !isVisible(RC))
+ return true;
+ if (MD->isDependentContext() || !MD->hasBody())
+ return true;
+ }
+ if (FD->getStorageClass() == StorageClass::SC_Static)
+ return true;
+ }
+ return false;
+ };
+
+ auto getParentFunctionDecl = [](const NamedDecl *ND) -> const NamedDecl * {
+ if (const VarDecl *VD = dyn_cast<VarDecl>(ND))
+ if (const auto *FD =
+ dyn_cast_or_null<FunctionDecl>(VD->getParentFunctionOrMethod()))
+ return FD;
+ return nullptr;
+ };
+
+ auto getMangledNames = [](const NamedDecl *ND) -> std::vector<std::string> {
+ if (!ND)
+ return {""};
+ ASTNameGenerator NameGen(ND->getASTContext());
+ std::vector<std::string> MangledNames = NameGen.getAllManglings(ND);
+ if (isa<CXXConstructorDecl>(ND) || isa<CXXDestructorDecl>(ND))
+ return MangledNames;
+#ifdef EXPENSIVE_CHECKS
+ assert(MangledNames.size() <= 1 && "Expected only one name mangling.");
+#endif
+ return {NameGen.getName(ND)};
+ };
+
+ if (!(RDO & FromTU))
+ return true;
+ if (Symbols.find(ND) != Symbols.end())
+ return true;
+ // - Currently have not figured out how to produce the names for FieldDecls.
+ // - Do not want to produce symbols for function paremeters.
+ if (isa<FieldDecl>(ND) || isa<ParmVarDecl>(ND))
+ return true;
+
+ const NamedDecl *ParentDecl = getParentFunctionDecl(ND);
+ if ((ParentDecl && ignoreDecl(ParentDecl)) || ignoreDecl(ND))
+ return true;
+
+ if (RDO & IsLate) {
+ Instance.getDiagnostics().Report(diag::err_asm_invalid_type_in_input)
+ << "Generating Interface Stubs is not supported with "
+ "delayed template parsing.";
+ } else {
+ if (const auto *FD = dyn_cast<FunctionDecl>(ND))
+ if (FD->isDependentContext())
+ return true;
+
+ const bool IsWeak = (ND->hasAttr<WeakAttr>() ||
+ ND->hasAttr<WeakRefAttr>() || ND->isWeakImported());
+
+ Symbols.insert(std::make_pair(
+ ND,
+ MangledSymbol(getMangledNames(ParentDecl).front(),
+ // Type:
+ isa<VarDecl>(ND) ? llvm::ELF::STT_OBJECT
+ : llvm::ELF::STT_FUNC,
+ // Binding:
+ IsWeak ? llvm::ELF::STB_WEAK : llvm::ELF::STB_GLOBAL,
+ getMangledNames(ND))));
+ }
+ return true;
+ }
+
+ void
+ HandleDecls(const llvm::iterator_range<DeclContext::decl_iterator> &Decls,
+ MangledSymbols &Symbols, int RDO) {
+ for (const auto *D : Decls)
+ HandleNamedDecl(dyn_cast<NamedDecl>(D), Symbols, RDO);
+ }
+
+ void HandleTemplateSpecializations(const FunctionTemplateDecl &FTD,
+ MangledSymbols &Symbols, int RDO) {
+ for (const auto *D : FTD.specializations())
+ HandleNamedDecl(dyn_cast<NamedDecl>(D), Symbols, RDO);
+ }
+
+ void HandleTemplateSpecializations(const ClassTemplateDecl &CTD,
+ MangledSymbols &Symbols, int RDO) {
+ for (const auto *D : CTD.specializations())
+ HandleNamedDecl(dyn_cast<NamedDecl>(D), Symbols, RDO);
+ }
+
+ bool HandleNamedDecl(const NamedDecl *ND, MangledSymbols &Symbols, int RDO) {
+ if (!ND)
+ return false;
+
+ switch (ND->getKind()) {
+ default:
+ break;
+ case Decl::Kind::Namespace:
+ HandleDecls(cast<NamespaceDecl>(ND)->decls(), Symbols, RDO);
+ return true;
+ case Decl::Kind::CXXRecord:
+ HandleDecls(cast<CXXRecordDecl>(ND)->decls(), Symbols, RDO);
+ return true;
+ case Decl::Kind::ClassTemplateSpecialization:
+ HandleDecls(cast<ClassTemplateSpecializationDecl>(ND)->decls(), Symbols,
+ RDO);
+ return true;
+ case Decl::Kind::ClassTemplate:
+ HandleTemplateSpecializations(*cast<ClassTemplateDecl>(ND), Symbols, RDO);
+ return true;
+ case Decl::Kind::FunctionTemplate:
+ HandleTemplateSpecializations(*cast<FunctionTemplateDecl>(ND), Symbols,
+ RDO);
+ return true;
+ case Decl::Kind::TemplateTypeParm:
+ return true;
+ case Decl::Kind::Var:
+ case Decl::Kind::ParmVar:
+ case Decl::Kind::CXXMethod:
+ case Decl::Kind::CXXConstructor:
+ case Decl::Kind::CXXDestructor:
+ case Decl::Kind::Function:
+ case Decl::Kind::Field:
+ if (WriteNamedDecl(ND, Symbols, RDO))
+ return true;
+ }
+
+ // While interface stubs are in the development stage, it's probably best to
+ // catch anything that's not a VarDecl or Template/FunctionDecl.
+ Instance.getDiagnostics().Report(diag::err_asm_invalid_type_in_input)
+ << "Expected a function or function template decl.";
+ return false;
+ }
+
+public:
+ InterfaceStubFunctionsConsumer(CompilerInstance &Instance, StringRef InFile,
+ StringRef Format)
+ : Instance(Instance), InFile(InFile), Format(Format) {}
+
+ void HandleTranslationUnit(ASTContext &context) override {
+ struct Visitor : public RecursiveASTVisitor<Visitor> {
+ bool VisitNamedDecl(NamedDecl *ND) {
+ if (const auto *FD = dyn_cast<FunctionDecl>(ND))
+ if (FD->isLateTemplateParsed()) {
+ LateParsedDecls.insert(FD);
+ return true;
+ }
+
+ if (const auto *VD = dyn_cast<ValueDecl>(ND)) {
+ ValueDecls.insert(VD);
+ return true;
+ }
+
+ NamedDecls.insert(ND);
+ return true;
+ }
+
+ std::set<const NamedDecl *> LateParsedDecls;
+ std::set<NamedDecl *> NamedDecls;
+ std::set<const ValueDecl *> ValueDecls;
+ } v;
+
+ v.TraverseDecl(context.getTranslationUnitDecl());
+
+ MangledSymbols Symbols;
+ auto OS = Instance.createDefaultOutputFile(/*Binary=*/false, InFile, "ifs");
+ if (!OS)
+ return;
+
+ if (Instance.getLangOpts().DelayedTemplateParsing) {
+ clang::Sema &S = Instance.getSema();
+ for (const auto *FD : v.LateParsedDecls) {
+ clang::LateParsedTemplate &LPT =
+ *S.LateParsedTemplateMap.find(cast<FunctionDecl>(FD))->second;
+ S.LateTemplateParser(S.OpaqueParser, LPT);
+ HandleNamedDecl(FD, Symbols, (FromTU | IsLate));
+ }
+ }
+
+ for (const NamedDecl *ND : v.ValueDecls)
+ HandleNamedDecl(ND, Symbols, FromTU);
+ for (const NamedDecl *ND : v.NamedDecls)
+ HandleNamedDecl(ND, Symbols, FromTU);
+
+ auto writeIfoYaml = [this](const llvm::Triple &T,
+ const MangledSymbols &Symbols,
+ const ASTContext &context, StringRef Format,
+ raw_ostream &OS) -> void {
+ OS << "--- !" << Format << "\n";
+ OS << "FileHeader:\n";
+ OS << " Class: ELFCLASS";
+ OS << (T.isArch64Bit() ? "64" : "32");
+ OS << "\n";
+ OS << " Data: ELFDATA2";
+ OS << (T.isLittleEndian() ? "LSB" : "MSB");
+ OS << "\n";
+ OS << " Type: ET_REL\n";
+ OS << " Machine: "
+ << llvm::StringSwitch<llvm::StringRef>(T.getArchName())
+ .Case("x86_64", "EM_X86_64")
+ .Case("i386", "EM_386")
+ .Case("i686", "EM_386")
+ .Case("aarch64", "EM_AARCH64")
+ .Case("amdgcn", "EM_AMDGPU")
+ .Case("r600", "EM_AMDGPU")
+ .Case("arm", "EM_ARM")
+ .Case("thumb", "EM_ARM")
+ .Case("avr", "EM_AVR")
+ .Case("mips", "EM_MIPS")
+ .Case("mipsel", "EM_MIPS")
+ .Case("mips64", "EM_MIPS")
+ .Case("mips64el", "EM_MIPS")
+ .Case("msp430", "EM_MSP430")
+ .Case("ppc", "EM_PPC")
+ .Case("ppc64", "EM_PPC64")
+ .Case("ppc64le", "EM_PPC64")
+ .Case("x86", T.isOSIAMCU() ? "EM_IAMCU" : "EM_386")
+ .Case("x86_64", "EM_X86_64")
+ .Default("EM_NONE")
+ << "\nSymbols:\n";
+ for (const auto &E : Symbols) {
+ const MangledSymbol &Symbol = E.second;
+ for (auto Name : Symbol.Names) {
+ OS << " - Name: "
+ << (Symbol.ParentName.empty() || Instance.getLangOpts().CPlusPlus
+ ? ""
+ : (Symbol.ParentName + "."))
+ << Name << "\n"
+ << " Type: STT_";
+ switch (Symbol.Type) {
+ default:
+ case llvm::ELF::STT_NOTYPE:
+ OS << "NOTYPE";
+ break;
+ case llvm::ELF::STT_OBJECT:
+ OS << "OBJECT";
+ break;
+ case llvm::ELF::STT_FUNC:
+ OS << "FUNC";
+ break;
+ }
+ OS << "\n Binding: STB_"
+ << ((Symbol.Binding == llvm::ELF::STB_WEAK) ? "WEAK" : "GLOBAL")
+ << "\n";
+ }
+ }
+ OS << "...\n";
+ OS.flush();
+ };
+
+ auto writeIfoElfAbiYaml =
+ [this](const llvm::Triple &T, const MangledSymbols &Symbols,
+ const ASTContext &context, StringRef Format,
+ raw_ostream &OS) -> void {
+ OS << "--- !" << Format << "\n";
+ OS << "TbeVersion: 1.0\n";
+ OS << "Arch: " << T.getArchName() << "\n";
+ OS << "Symbols:\n";
+ for (const auto &E : Symbols) {
+ const MangledSymbol &Symbol = E.second;
+ for (auto Name : Symbol.Names) {
+ OS << " "
+ << (Symbol.ParentName.empty() || Instance.getLangOpts().CPlusPlus
+ ? ""
+ : (Symbol.ParentName + "."))
+ << Name << ": { Type: ";
+ switch (Symbol.Type) {
+ default:
+ llvm_unreachable(
+ "clang -emit-iterface-stubs: Unexpected symbol type.");
+ case llvm::ELF::STT_NOTYPE:
+ OS << "NoType";
+ break;
+ case llvm::ELF::STT_OBJECT: {
+ auto VD = cast<ValueDecl>(E.first)->getType();
+ OS << "Object, Size: "
+ << context.getTypeSizeInChars(VD).getQuantity();
+ break;
+ }
+ case llvm::ELF::STT_FUNC:
+ OS << "Func";
+ break;
+ }
+ if (Symbol.Binding == llvm::ELF::STB_WEAK)
+ OS << ", Weak: true";
+ OS << " }\n";
+ }
+ }
+ OS << "...\n";
+ OS.flush();
+ };
+
+ if (Format == "experimental-yaml-elf-v1")
+ writeIfoYaml(Instance.getTarget().getTriple(), Symbols, context, Format,
+ *OS);
+ else
+ writeIfoElfAbiYaml(Instance.getTarget().getTriple(), Symbols, context,
+ Format, *OS);
+ }
+};
+
+std::unique_ptr<ASTConsumer>
+GenerateInterfaceYAMLExpV1Action::CreateASTConsumer(CompilerInstance &CI,
+ StringRef InFile) {
+ return llvm::make_unique<InterfaceStubFunctionsConsumer>(
+ CI, InFile, "experimental-yaml-elf-v1");
+}
+
+std::unique_ptr<ASTConsumer>
+GenerateInterfaceTBEExpV1Action::CreateASTConsumer(CompilerInstance &CI,
+ StringRef InFile) {
+ return llvm::make_unique<InterfaceStubFunctionsConsumer>(
+ CI, InFile, "experimental-tapi-elf-v1");
+}