libc/utils/HdrGen/PublicAPICommand.cpp - third_party/llvm-project - Git at Google

 //===-- Implementation of PublicAPICommand --------------------------------===//
 //
 // 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 "PublicAPICommand.h"

 #include "utils/LibcTableGenUtil/APIIndexer.h"

 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/TableGen/Record.h"
 #include <algorithm>
 #include <vector>

 // Text blocks for macro definitions and type decls can be indented to
 // suit the surrounding tablegen listing. We need to dedent such blocks
 // before writing them out.
 static void dedentAndWrite(llvm::StringRef Text, llvm::raw_ostream &OS) {
   llvm::SmallVector<llvm::StringRef, 10> Lines;
   llvm::SplitString(Text, Lines, "\n");
   size_t shortest_indent = 1024;
   for (llvm::StringRef L : Lines) {
     llvm::StringRef Indent = L.take_while([](char c) { return c == ' '; });
     size_t IndentSize = Indent.size();
     if (Indent.size() == L.size()) {
       // Line is all spaces so no point noting the indent.
       continue;
     }
     if (IndentSize < shortest_indent)
       shortest_indent = IndentSize;
   }
   for (llvm::StringRef L : Lines) {
     if (L.size() >= shortest_indent)
       OS << L.drop_front(shortest_indent) << '\n';
   }
 }

 static std::string getTypeHdrName(const std::string &Name) {
   llvm::SmallVector<llvm::StringRef> Parts;
   llvm::SplitString(llvm::StringRef(Name), Parts);
   return llvm::join(Parts.begin(), Parts.end(), "_");
 }

 namespace llvm_libc {

 static bool isAsciiStart(char C) {
   return (C >= 'A' && C <= 'Z') || (C >= 'a' && C <= 'z') || C == '_';
 }

 static bool isAsciiContinue(char C) {
   return isAsciiStart(C) || (C >= '0' && C <= '9');
 }

 static bool isAsciiIdentifier(llvm::StringRef S) {
   if (S.empty())
     return false;
   if (!isAsciiStart(S[0]))
     return false;
   for (char C : S.drop_front())
     if (!isAsciiContinue(C))
       return false;
   return true;
 }

 static AttributeStyle getAttributeStyle(llvm::Record *Instance) {
   llvm::StringRef Style = Instance->getValueAsString("Style");
   return llvm::StringSwitch<AttributeStyle>(Style)
       .Case("cxx11", AttributeStyle::Cxx11)
       .Case("gnu", AttributeStyle::Gnu)
       .Case("declspec", AttributeStyle::Declspec)
       .Default(AttributeStyle::Gnu);
 }

 static AttributeNamespace getAttributeNamespace(llvm::Record *Instance) {
   llvm::StringRef Namespace = Instance->getValueAsString("Namespace");
   return llvm::StringSwitch<AttributeNamespace>(Namespace)
       .Case("clang", AttributeNamespace::Clang)
       .Case("gnu", AttributeNamespace::Gnu)
       .Default(AttributeNamespace::None);
 }

 using AttributeMap = llvm::DenseMap<llvm::StringRef, llvm::Record *>;

 template <class SpecMap, class FuncList>
 static AttributeMap collectAttributeMacros(const SpecMap &Spec,
                                            const FuncList &Funcs) {
   llvm::DenseMap<llvm::StringRef, llvm::Record *> MacroAttr;
   for (const auto &Name : Funcs) {
     auto Iter = Spec.find(Name);
     if (Iter == Spec.end())
       continue;

     llvm::Record *FunctionSpec = Iter->second;
     std::vector<llvm::Record *> Attributes =
         FunctionSpec->getValueAsListOfDefs("Attributes");
     for (llvm::Record *Attr : Attributes)
       MacroAttr[Attr->getValueAsString("Macro")] = Attr;
   }
   return MacroAttr;
 }

 static void emitAttributeMacroDecls(const AttributeMap &MacroAttr,
                                     llvm::raw_ostream &OS) {
   for (auto &[Macro, Attr] : MacroAttr) {
     std::vector<llvm::Record *> Instances =
         Attr->getValueAsListOfDefs("Instances");
     llvm::SmallVector<std::pair<AttributeStyle, llvm::Record *>> Styles;
     std::transform(Instances.begin(), Instances.end(),
                    std::back_inserter(Styles),
                    [&](llvm::Record *Instance)
                        -> std::pair<AttributeStyle, llvm::Record *> {
                      auto Style = getAttributeStyle(Instance);
                      return {Style, Instance};
                    });
     // 1. If __cplusplus is defined and cxx11 style is provided, define the
     // macro using cxx11 version with the following priority:
     //    1a. If there is no namespace (so the macro is supposed to be
     //        compiler-independent), use this version first. This macro will be
     //        tested via __has_cpp_attribute.
     //    1b. If the attribute is a clang attribute, check for __clang__.
     //    1c. If the attribute is a gnu attribute, check for __GNUC__.
     // 2. Otherwise, if __GNUC__ is defined and gnu style is provided,
     //    define the macro using gnu version;
     // 3. Otherwise, if _MSC_VER is defined and __declspec is provided, define
     //    the macro using __declspec version;
     // 4. Fallback to empty macro.
     std::sort(Styles.begin(), Styles.end(), [&](auto &a, auto &b) {
       if (a.first == AttributeStyle::Cxx11 && b.first == AttributeStyle::Cxx11)
         return getAttributeNamespace(a.second) <
                getAttributeNamespace(b.second);
       return a.first < b.first;
     });
     for (auto &[Style, Instance] : Styles) {
       llvm::StringRef Attr = Instance->getValueAsString("Attr");
       if (Style == AttributeStyle::Cxx11) {
         OS << "#if !defined(" << Macro << ") && defined(__cplusplus)";
         AttributeNamespace Namespace = getAttributeNamespace(Instance);
         if (Namespace == AttributeNamespace::Clang)
           OS << " && defined(__clang__)\n";
         else if (Namespace == AttributeNamespace::Gnu)
           OS << " && defined(__GNUC__)\n";
         else
           OS << '\n';
         if (isAsciiIdentifier(Attr) && Namespace != AttributeNamespace::None)
           OS << "#if __has_attribute(" << Attr << ")\n";
         else
           OS << "#if __has_cpp_attribute(" << Attr << ")\n";
         OS << "#define " << Macro << " [[";
         if (Namespace == AttributeNamespace::Clang)
           OS << "clang::";
         else if (Namespace == AttributeNamespace::Gnu)
           OS << "gnu::";
         OS << Attr << "]]\n";
         if (isAsciiIdentifier(Attr))
           OS << "#endif\n";
         OS << "#endif\n";
       }
       if (Style == AttributeStyle::Gnu) {
         OS << "#if !defined(" << Macro << ") && defined(__GNUC__)\n";
         if (isAsciiIdentifier(Attr))
           OS << "#if __has_attribute(" << Attr << ")\n";
         OS << "#define " << Macro << " __attribute__((";
         OS << Attr << "))\n";
         if (isAsciiIdentifier(Attr))
           OS << "#endif\n";
         OS << "#endif\n";
       }
       if (Style == AttributeStyle::Declspec) {
         OS << "#if !defined(" << Macro << ") && defined(_MSC_VER)\n";
         OS << "#define " << Macro << " __declspec(";
         OS << Attr << ")\n";
         OS << "#endif\n";
       }
     }
     OS << "#if !defined(" << Macro << ")\n";
     OS << "#define " << Macro << '\n';
     OS << "#endif\n";
   }

   if (!MacroAttr.empty())
     OS << '\n';
 }

 static void emitAttributeMacroForFunction(const llvm::Record *FunctionSpec,
                                           llvm::raw_ostream &OS) {
   std::vector<llvm::Record *> Attributes =
       FunctionSpec->getValueAsListOfDefs("Attributes");
   llvm::interleave(
       Attributes.begin(), Attributes.end(),
       [&](llvm::Record *Attr) { OS << Attr->getValueAsString("Macro"); },
       [&]() { OS << ' '; });
   if (!Attributes.empty())
     OS << ' ';
 }

 static void emitUndefsForAttributeMacros(const AttributeMap &MacroAttr,
                                          llvm::raw_ostream &OS) {
   if (!MacroAttr.empty())
     OS << '\n';
   for (auto &[Macro, Attr] : MacroAttr)
     OS << "#undef " << Macro << '\n';
 }

 static void writeAPIFromIndex(APIIndexer &G,
                               std::vector<std::string> EntrypointNameList,
                               llvm::raw_ostream &OS) {
   for (auto &Pair : G.MacroDefsMap) {
     const std::string &Name = Pair.first;
     if (!G.MacroSpecMap.count(Name))
       llvm::PrintFatalError(Name + " not found in any standard spec.\n");

     llvm::Record *MacroDef = Pair.second;
     dedentAndWrite(MacroDef->getValueAsString("Defn"), OS);

     OS << '\n';
   }

   for (auto &TypeName : G.RequiredTypes) {
     if (!G.TypeSpecMap.count(TypeName))
       llvm::PrintFatalError(TypeName + " not found in any standard spec.\n");
     OS << "#include <llvm-libc-types/" << getTypeHdrName(TypeName) << ".h>\n";
   }
   OS << '\n';

   if (G.Enumerations.size() != 0)
     OS << "enum {" << '\n';
   for (const auto &Name : G.Enumerations) {
     if (!G.EnumerationSpecMap.count(Name))
       llvm::PrintFatalError(
           Name + " is not listed as an enumeration in any standard spec.\n");

     llvm::Record *EnumerationSpec = G.EnumerationSpecMap[Name];
     OS << "  " << EnumerationSpec->getValueAsString("Name");
     auto Value = EnumerationSpec->getValueAsString("Value");
     if (Value == "__default__") {
       OS << ",\n";
     } else {
       OS << " = " << Value << ",\n";
     }
   }
   if (G.Enumerations.size() != 0)
     OS << "};\n\n";

   // Collect and declare macros for attributes
   AttributeMap MacroAttr =
       collectAttributeMacros(G.FunctionSpecMap, EntrypointNameList);
   emitAttributeMacroDecls(MacroAttr, OS);

   OS << "__BEGIN_C_DECLS\n\n";
   for (auto &Name : EntrypointNameList) {
     auto Iter = G.FunctionSpecMap.find(Name);

     // Functions that aren't in this header file are skipped as
     // opposed to erroring out because the list of functions being
     // iterated over is the complete list of functions with
     // entrypoints. Thus this is filtering out the functions that
     // don't go to this header file, whereas the other, similar
     // conditionals above are more of a sanity check.
     if (Iter == G.FunctionSpecMap.end())
       continue;

     llvm::Record *FunctionSpec = Iter->second;
     llvm::Record *RetValSpec = FunctionSpec->getValueAsDef("Return");
     llvm::Record *ReturnType = RetValSpec->getValueAsDef("ReturnType");

     // TODO: https://github.com/llvm/llvm-project/issues/81208
     //   Ideally, we should group functions based on their guarding macros.
     bool Guarded =
         (FunctionSpec->getType()->getAsString() == "GuardedFunctionSpec");

     if (Guarded)
       OS << "#ifdef " << FunctionSpec->getValueAsString("Guard") << "\n";

     // Emit attribute macros for the function. Space is automatically added.
     emitAttributeMacroForFunction(FunctionSpec, OS);
     OS << G.getTypeAsString(ReturnType) << " " << Name << "(";

     auto ArgsList = FunctionSpec->getValueAsListOfDefs("Args");
     for (size_t i = 0; i < ArgsList.size(); ++i) {
       llvm::Record *ArgType = ArgsList[i]->getValueAsDef("ArgType");
       OS << G.getTypeAsString(ArgType);
       if (i < ArgsList.size() - 1)
         OS << ", ";
     }

     OS << ") __NOEXCEPT;\n";

     if (Guarded)
       OS << "#endif // " << FunctionSpec->getValueAsString("Guard") << "\n";

     OS << "\n";
   }

   // Make another pass over entrypoints to emit object declarations.
   for (const auto &Name : EntrypointNameList) {
     auto Iter = G.ObjectSpecMap.find(Name);
     if (Iter == G.ObjectSpecMap.end())
       continue;
     llvm::Record *ObjectSpec = Iter->second;
     auto Type = ObjectSpec->getValueAsString("Type");
     OS << "extern " << Type << " " << Name << ";\n";
   }
   OS << "__END_C_DECLS\n";

   // Undef file-level attribute macros.
   emitUndefsForAttributeMacros(MacroAttr, OS);
 }

 void writePublicAPI(llvm::raw_ostream &OS, llvm::RecordKeeper &Records) {}

 const char PublicAPICommand::Name[] = "public_api";

 void PublicAPICommand::run(llvm::raw_ostream &OS, const ArgVector &Args,
                            llvm::StringRef StdHeader,
                            llvm::RecordKeeper &Records,
                            const Command::ErrorReporter &Reporter) const {
   if (Args.size() != 0)
     Reporter.printFatalError("public_api command does not take any arguments.");

   APIIndexer G(StdHeader, Records);
   writeAPIFromIndex(G, EntrypointNameList, OS);
 }

 } // namespace llvm_libc
	//===-- Implementation of PublicAPICommand --------------------------------===//
	//
	// 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 "PublicAPICommand.h"

	#include "utils/LibcTableGenUtil/APIIndexer.h"

	#include "llvm/ADT/STLExtras.h"
	#include "llvm/ADT/SmallVector.h"
	#include "llvm/ADT/StringExtras.h"
	#include "llvm/ADT/StringRef.h"
	#include "llvm/ADT/StringSwitch.h"
	#include "llvm/Support/SourceMgr.h"
	#include "llvm/TableGen/Record.h"
	#include <algorithm>
	#include <vector>

	// Text blocks for macro definitions and type decls can be indented to
	// suit the surrounding tablegen listing. We need to dedent such blocks
	// before writing them out.
	static void dedentAndWrite(llvm::StringRef Text, llvm::raw_ostream &OS) {
	llvm::SmallVector<llvm::StringRef, 10> Lines;
	llvm::SplitString(Text, Lines, "\n");
	size_t shortest_indent = 1024;
	for (llvm::StringRef L : Lines) {
	llvm::StringRef Indent = L.take_while([](char c) { return c == ' '; });
	size_t IndentSize = Indent.size();
	if (Indent.size() == L.size()) {
	// Line is all spaces so no point noting the indent.
	continue;
	}
	if (IndentSize < shortest_indent)
	shortest_indent = IndentSize;
	}
	for (llvm::StringRef L : Lines) {
	if (L.size() >= shortest_indent)
	OS << L.drop_front(shortest_indent) << '\n';
	}
	}

	static std::string getTypeHdrName(const std::string &Name) {
	llvm::SmallVector<llvm::StringRef> Parts;
	llvm::SplitString(llvm::StringRef(Name), Parts);
	return llvm::join(Parts.begin(), Parts.end(), "_");
	}

	namespace llvm_libc {

	static bool isAsciiStart(char C) {
	return (C >= 'A' && C <= 'Z') \|\| (C >= 'a' && C <= 'z') \|\| C == '_';
	}

	static bool isAsciiContinue(char C) {
	return isAsciiStart(C) \|\| (C >= '0' && C <= '9');
	}

	static bool isAsciiIdentifier(llvm::StringRef S) {
	if (S.empty())
	return false;
	if (!isAsciiStart(S[0]))
	return false;
	for (char C : S.drop_front())
	if (!isAsciiContinue(C))
	return false;
	return true;
	}

	static AttributeStyle getAttributeStyle(llvm::Record *Instance) {
	llvm::StringRef Style = Instance->getValueAsString("Style");
	return llvm::StringSwitch<AttributeStyle>(Style)
	.Case("cxx11", AttributeStyle::Cxx11)
	.Case("gnu", AttributeStyle::Gnu)
	.Case("declspec", AttributeStyle::Declspec)
	.Default(AttributeStyle::Gnu);
	}

	static AttributeNamespace getAttributeNamespace(llvm::Record *Instance) {
	llvm::StringRef Namespace = Instance->getValueAsString("Namespace");
	return llvm::StringSwitch<AttributeNamespace>(Namespace)
	.Case("clang", AttributeNamespace::Clang)
	.Case("gnu", AttributeNamespace::Gnu)
	.Default(AttributeNamespace::None);
	}

	using AttributeMap = llvm::DenseMap<llvm::StringRef, llvm::Record *>;

	template <class SpecMap, class FuncList>
	static AttributeMap collectAttributeMacros(const SpecMap &Spec,
	const FuncList &Funcs) {
	llvm::DenseMap<llvm::StringRef, llvm::Record *> MacroAttr;
	for (const auto &Name : Funcs) {
	auto Iter = Spec.find(Name);
	if (Iter == Spec.end())
	continue;

	llvm::Record *FunctionSpec = Iter->second;
	std::vector<llvm::Record *> Attributes =
	FunctionSpec->getValueAsListOfDefs("Attributes");
	for (llvm::Record *Attr : Attributes)
	MacroAttr[Attr->getValueAsString("Macro")] = Attr;
	}
	return MacroAttr;
	}

	static void emitAttributeMacroDecls(const AttributeMap &MacroAttr,
	llvm::raw_ostream &OS) {
	for (auto &[Macro, Attr] : MacroAttr) {
	std::vector<llvm::Record *> Instances =
	Attr->getValueAsListOfDefs("Instances");
	llvm::SmallVector<std::pair<AttributeStyle, llvm::Record *>> Styles;
	std::transform(Instances.begin(), Instances.end(),
	std::back_inserter(Styles),
	[&](llvm::Record *Instance)
	-> std::pair<AttributeStyle, llvm::Record *> {
	auto Style = getAttributeStyle(Instance);
	return {Style, Instance};
	});
	// 1. If __cplusplus is defined and cxx11 style is provided, define the
	// macro using cxx11 version with the following priority:
	// 1a. If there is no namespace (so the macro is supposed to be
	// compiler-independent), use this version first. This macro will be
	// tested via __has_cpp_attribute.
	// 1b. If the attribute is a clang attribute, check for __clang__.
	// 1c. If the attribute is a gnu attribute, check for __GNUC__.
	// 2. Otherwise, if __GNUC__ is defined and gnu style is provided,
	// define the macro using gnu version;
	// 3. Otherwise, if _MSC_VER is defined and __declspec is provided, define
	// the macro using __declspec version;
	// 4. Fallback to empty macro.
	std::sort(Styles.begin(), Styles.end(), [&](auto &a, auto &b) {
	if (a.first == AttributeStyle::Cxx11 && b.first == AttributeStyle::Cxx11)
	return getAttributeNamespace(a.second) <
	getAttributeNamespace(b.second);
	return a.first < b.first;
	});
	for (auto &[Style, Instance] : Styles) {
	llvm::StringRef Attr = Instance->getValueAsString("Attr");
	if (Style == AttributeStyle::Cxx11) {
	OS << "#if !defined(" << Macro << ") && defined(__cplusplus)";
	AttributeNamespace Namespace = getAttributeNamespace(Instance);
	if (Namespace == AttributeNamespace::Clang)
	OS << " && defined(__clang__)\n";
	else if (Namespace == AttributeNamespace::Gnu)
	OS << " && defined(__GNUC__)\n";
	else
	OS << '\n';
	if (isAsciiIdentifier(Attr) && Namespace != AttributeNamespace::None)
	OS << "#if __has_attribute(" << Attr << ")\n";
	else
	OS << "#if __has_cpp_attribute(" << Attr << ")\n";
	OS << "#define " << Macro << " [[";
	if (Namespace == AttributeNamespace::Clang)
	OS << "clang::";
	else if (Namespace == AttributeNamespace::Gnu)
	OS << "gnu::";
	OS << Attr << "]]\n";
	if (isAsciiIdentifier(Attr))
	OS << "#endif\n";
	OS << "#endif\n";
	}
	if (Style == AttributeStyle::Gnu) {
	OS << "#if !defined(" << Macro << ") && defined(__GNUC__)\n";
	if (isAsciiIdentifier(Attr))
	OS << "#if __has_attribute(" << Attr << ")\n";
	OS << "#define " << Macro << " __attribute__((";
	OS << Attr << "))\n";
	if (isAsciiIdentifier(Attr))
	OS << "#endif\n";
	OS << "#endif\n";
	}
	if (Style == AttributeStyle::Declspec) {
	OS << "#if !defined(" << Macro << ") && defined(_MSC_VER)\n";
	OS << "#define " << Macro << " __declspec(";
	OS << Attr << ")\n";
	OS << "#endif\n";
	}
	}
	OS << "#if !defined(" << Macro << ")\n";
	OS << "#define " << Macro << '\n';
	OS << "#endif\n";
	}

	if (!MacroAttr.empty())
	OS << '\n';
	}

	static void emitAttributeMacroForFunction(const llvm::Record *FunctionSpec,
	llvm::raw_ostream &OS) {
	std::vector<llvm::Record *> Attributes =
	FunctionSpec->getValueAsListOfDefs("Attributes");
	llvm::interleave(
	Attributes.begin(), Attributes.end(),
	[&](llvm::Record *Attr) { OS << Attr->getValueAsString("Macro"); },
	[&]() { OS << ' '; });
	if (!Attributes.empty())
	OS << ' ';
	}

	static void emitUndefsForAttributeMacros(const AttributeMap &MacroAttr,
	llvm::raw_ostream &OS) {
	if (!MacroAttr.empty())
	OS << '\n';
	for (auto &[Macro, Attr] : MacroAttr)
	OS << "#undef " << Macro << '\n';
	}

	static void writeAPIFromIndex(APIIndexer &G,
	std::vector<std::string> EntrypointNameList,
	llvm::raw_ostream &OS) {
	for (auto &Pair : G.MacroDefsMap) {
	const std::string &Name = Pair.first;
	if (!G.MacroSpecMap.count(Name))
	llvm::PrintFatalError(Name + " not found in any standard spec.\n");

	llvm::Record *MacroDef = Pair.second;
	dedentAndWrite(MacroDef->getValueAsString("Defn"), OS);

	OS << '\n';
	}

	for (auto &TypeName : G.RequiredTypes) {
	if (!G.TypeSpecMap.count(TypeName))
	llvm::PrintFatalError(TypeName + " not found in any standard spec.\n");
	OS << "#include <llvm-libc-types/" << getTypeHdrName(TypeName) << ".h>\n";
	}
	OS << '\n';

	if (G.Enumerations.size() != 0)
	OS << "enum {" << '\n';
	for (const auto &Name : G.Enumerations) {
	if (!G.EnumerationSpecMap.count(Name))
	llvm::PrintFatalError(
	Name + " is not listed as an enumeration in any standard spec.\n");

	llvm::Record *EnumerationSpec = G.EnumerationSpecMap[Name];
	OS << " " << EnumerationSpec->getValueAsString("Name");
	auto Value = EnumerationSpec->getValueAsString("Value");
	if (Value == "__default__") {
	OS << ",\n";
	} else {
	OS << " = " << Value << ",\n";
	}
	}
	if (G.Enumerations.size() != 0)
	OS << "};\n\n";

	// Collect and declare macros for attributes
	AttributeMap MacroAttr =
	collectAttributeMacros(G.FunctionSpecMap, EntrypointNameList);
	emitAttributeMacroDecls(MacroAttr, OS);

	OS << "__BEGIN_C_DECLS\n\n";
	for (auto &Name : EntrypointNameList) {
	auto Iter = G.FunctionSpecMap.find(Name);

	// Functions that aren't in this header file are skipped as
	// opposed to erroring out because the list of functions being
	// iterated over is the complete list of functions with
	// entrypoints. Thus this is filtering out the functions that
	// don't go to this header file, whereas the other, similar
	// conditionals above are more of a sanity check.
	if (Iter == G.FunctionSpecMap.end())
	continue;

	llvm::Record *FunctionSpec = Iter->second;
	llvm::Record *RetValSpec = FunctionSpec->getValueAsDef("Return");
	llvm::Record *ReturnType = RetValSpec->getValueAsDef("ReturnType");

	// TODO: https://github.com/llvm/llvm-project/issues/81208
	// Ideally, we should group functions based on their guarding macros.
	bool Guarded =
	(FunctionSpec->getType()->getAsString() == "GuardedFunctionSpec");

	if (Guarded)
	OS << "#ifdef " << FunctionSpec->getValueAsString("Guard") << "\n";

	// Emit attribute macros for the function. Space is automatically added.
	emitAttributeMacroForFunction(FunctionSpec, OS);
	OS << G.getTypeAsString(ReturnType) << " " << Name << "(";

	auto ArgsList = FunctionSpec->getValueAsListOfDefs("Args");
	for (size_t i = 0; i < ArgsList.size(); ++i) {
	llvm::Record *ArgType = ArgsList[i]->getValueAsDef("ArgType");
	OS << G.getTypeAsString(ArgType);
	if (i < ArgsList.size() - 1)
	OS << ", ";
	}

	OS << ") __NOEXCEPT;\n";

	if (Guarded)
	OS << "#endif // " << FunctionSpec->getValueAsString("Guard") << "\n";

	OS << "\n";
	}

	// Make another pass over entrypoints to emit object declarations.
	for (const auto &Name : EntrypointNameList) {
	auto Iter = G.ObjectSpecMap.find(Name);
	if (Iter == G.ObjectSpecMap.end())
	continue;
	llvm::Record *ObjectSpec = Iter->second;
	auto Type = ObjectSpec->getValueAsString("Type");
	OS << "extern " << Type << " " << Name << ";\n";
	}
	OS << "__END_C_DECLS\n";

	// Undef file-level attribute macros.
	emitUndefsForAttributeMacros(MacroAttr, OS);
	}

	void writePublicAPI(llvm::raw_ostream &OS, llvm::RecordKeeper &Records) {}

	const char PublicAPICommand::Name[] = "public_api";

	void PublicAPICommand::run(llvm::raw_ostream &OS, const ArgVector &Args,
	llvm::StringRef StdHeader,
	llvm::RecordKeeper &Records,
	const Command::ErrorReporter &Reporter) const {
	if (Args.size() != 0)
	Reporter.printFatalError("public_api command does not take any arguments.");

	APIIndexer G(StdHeader, Records);
	writeAPIFromIndex(G, EntrypointNameList, OS);
	}

	} // namespace llvm_libc