libc/utils/HdrGen/PublicAPICommand.cpp

//===-- 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 "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/TableGen/Error.h"
#include "llvm/TableGen/Record.h"

static const char NamedTypeClassName[] = "NamedType";
static const char PtrTypeClassName[] = "PtrType";
static const char RestrictedPtrTypeClassName[] = "RestrictedPtrType";
static const char ConstTypeClassName[] = "ConstType";
static const char StructTypeClassName[] = "Struct";

static const char StandardSpecClassName[] = "StandardSpec";
static const char PublicAPIClassName[] = "PublicAPI";

static bool isa(llvm::Record *Def, llvm::Record *TypeClass) {
  llvm::RecordRecTy *RecordType = Def->getType();
  llvm::ArrayRef<llvm::Record *> Classes = RecordType->getClasses();
  // We want exact types. That is, we don't want the classes listed in
  // spec.td to be subclassed. Hence, we do not want the record |Def|
  // to be of more than one class type..
  if (Classes.size() != 1)
    return false;
  return Classes[0] == TypeClass;
}

// 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';
  }
}

namespace llvm_libc {

bool APIIndexer::isaNamedType(llvm::Record *Def) {
  return isa(Def, NamedTypeClass);
}

bool APIIndexer::isaStructType(llvm::Record *Def) {
  return isa(Def, StructClass);
}

bool APIIndexer::isaPtrType(llvm::Record *Def) {
  return isa(Def, PtrTypeClass);
}

bool APIIndexer::isaConstType(llvm::Record *Def) {
  return isa(Def, ConstTypeClass);
}

bool APIIndexer::isaRestrictedPtrType(llvm::Record *Def) {
  return isa(Def, RestrictedPtrTypeClass);
}

bool APIIndexer::isaStandardSpec(llvm::Record *Def) {
  return isa(Def, StandardSpecClass);
}

bool APIIndexer::isaPublicAPI(llvm::Record *Def) {
  return isa(Def, PublicAPIClass);
}

std::string APIIndexer::getTypeAsString(llvm::Record *TypeRecord) {
  if (isaNamedType(TypeRecord) || isaStructType(TypeRecord)) {
    return std::string(TypeRecord->getValueAsString("Name"));
  } else if (isaPtrType(TypeRecord)) {
    return getTypeAsString(TypeRecord->getValueAsDef("PointeeType")) + " *";
  } else if (isaConstType(TypeRecord)) {
    return std::string("const ") +
           getTypeAsString(TypeRecord->getValueAsDef("UnqualifiedType"));
  } else if (isaRestrictedPtrType(TypeRecord)) {
    return getTypeAsString(TypeRecord->getValueAsDef("PointeeType")) +
           " *__restrict";
  } else {
    llvm::PrintFatalError(TypeRecord->getLoc(), "Invalid type.\n");
  }
}

void APIIndexer::indexStandardSpecDef(llvm::Record *StandardSpec) {
  auto HeaderSpecList = StandardSpec->getValueAsListOfDefs("Headers");
  for (llvm::Record *HeaderSpec : HeaderSpecList) {
    llvm::StringRef Header = HeaderSpec->getValueAsString("Name");
    if (!StdHeader.hasValue() || Header == StdHeader) {
      PublicHeaders.emplace(Header);
      auto MacroSpecList = HeaderSpec->getValueAsListOfDefs("Macros");
      // TODO: Trigger a fatal error on duplicate specs.
      for (llvm::Record *MacroSpec : MacroSpecList)
        MacroSpecMap[std::string(MacroSpec->getValueAsString("Name"))] =
            MacroSpec;

      auto TypeSpecList = HeaderSpec->getValueAsListOfDefs("Types");
      for (llvm::Record *TypeSpec : TypeSpecList)
        TypeSpecMap[std::string(TypeSpec->getValueAsString("Name"))] = TypeSpec;

      auto FunctionSpecList = HeaderSpec->getValueAsListOfDefs("Functions");
      for (llvm::Record *FunctionSpec : FunctionSpecList) {
        FunctionSpecMap[std::string(FunctionSpec->getValueAsString("Name"))] =
            FunctionSpec;
      }

      auto EnumerationSpecList =
          HeaderSpec->getValueAsListOfDefs("Enumerations");
      for (llvm::Record *EnumerationSpec : EnumerationSpecList) {
        EnumerationSpecMap[std::string(
            EnumerationSpec->getValueAsString("Name"))] = EnumerationSpec;
      }
    }
  }
}

void APIIndexer::indexPublicAPIDef(llvm::Record *PublicAPI) {
  // While indexing the public API, we do not check if any of the entities
  // requested is from an included standard. Such a check is done while
  // generating the API.
  auto MacroDefList = PublicAPI->getValueAsListOfDefs("Macros");
  for (llvm::Record *MacroDef : MacroDefList)
    MacroDefsMap[std::string(MacroDef->getValueAsString("Name"))] = MacroDef;

  auto TypeDeclList = PublicAPI->getValueAsListOfDefs("TypeDeclarations");
  for (llvm::Record *TypeDecl : TypeDeclList)
    TypeDeclsMap[std::string(TypeDecl->getValueAsString("Name"))] = TypeDecl;

  auto StructList = PublicAPI->getValueAsListOfStrings("Structs");
  for (llvm::StringRef StructName : StructList)
    Structs.insert(std::string(StructName));

  auto FunctionList = PublicAPI->getValueAsListOfStrings("Functions");
  for (llvm::StringRef FunctionName : FunctionList)
    Functions.insert(std::string(FunctionName));

  auto EnumerationList = PublicAPI->getValueAsListOfStrings("Enumerations");
  for (llvm::StringRef EnumerationName : EnumerationList)
    Enumerations.insert(std::string(EnumerationName));
}

void APIIndexer::index(llvm::RecordKeeper &Records) {
  NamedTypeClass = Records.getClass(NamedTypeClassName);
  PtrTypeClass = Records.getClass(PtrTypeClassName);
  RestrictedPtrTypeClass = Records.getClass(RestrictedPtrTypeClassName);
  StructClass = Records.getClass(StructTypeClassName);
  ConstTypeClass = Records.getClass(ConstTypeClassName);
  StandardSpecClass = Records.getClass(StandardSpecClassName);
  PublicAPIClass = Records.getClass(PublicAPIClassName);

  const auto &DefsMap = Records.getDefs();
  for (auto &Pair : DefsMap) {
    llvm::Record *Def = Pair.second.get();
    if (isaStandardSpec(Def))
      indexStandardSpecDef(Def);
    if (isaPublicAPI(Def)) {
      if (!StdHeader.hasValue() ||
          Def->getValueAsString("HeaderName") == StdHeader)
        indexPublicAPIDef(Def);
    }
  }
}

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

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

    OS << '\n';
  }

  for (auto &Pair : G.TypeDeclsMap) {
    const std::string &Name = Pair.first;
    if (G.TypeSpecMap.find(Name) == G.TypeSpecMap.end())
      llvm::PrintFatalError(Name + " not found in any standard spec.\n");

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

    OS << '\n';
  }

  if (G.Enumerations.size() != 0)
    OS << "enum {" << '\n';
  for (const auto &Name : G.Enumerations) {
    if (G.EnumerationSpecMap.find(Name) == G.EnumerationSpecMap.end())
      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";

  OS << "__BEGIN_C_DECLS\n\n";
  for (auto &Name : G.Functions) {
    if (G.FunctionSpecMap.find(Name) == G.FunctionSpecMap.end())
      llvm::PrintFatalError(Name + " not found in any standard spec.\n");

    llvm::Record *FunctionSpec = G.FunctionSpecMap[Name];
    llvm::Record *RetValSpec = FunctionSpec->getValueAsDef("Return");
    llvm::Record *ReturnType = RetValSpec->getValueAsDef("ReturnType");

    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 << ");\n\n";
  }
  OS << "__END_C_DECLS\n";
}

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, OS);
}

} // namespace llvm_libc