//===--- Builtins.cpp - Builtin function implementation -------------------===//

//

// 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

//

//===----------------------------------------------------------------------===//

//

//  This file implements various things for builtin functions.

//

//===----------------------------------------------------------------------===//

#include "clang/Basic/Builtins.h"

#include "BuiltinTargetFeatures.h"

#include "clang/Basic/IdentifierTable.h"

#include "clang/Basic/LangOptions.h"

#include "clang/Basic/TargetInfo.h"

#include "llvm/ADT/StringRef.h"

using namespace clang;

const char *HeaderDesc::getName() const {

  switch (ID) {

#define HEADER(ID, NAME)                                                       \

  case ID:                                                                     \

    return NAME;

#include "clang/Basic/BuiltinHeaders.def"

#undef HEADER

  };

  llvm_unreachable("Unknown HeaderDesc::HeaderID enum");

}

static constexpr Builtin::Info BuiltinInfo[] = {

    {"not a builtin function", nullptr, nullptr, nullptr, HeaderDesc::NO_HEADER,

     ALL_LANGUAGES},

#define BUILTIN(ID, TYPE, ATTRS)                                               \

  {#ID, TYPE, ATTRS, nullptr, HeaderDesc::NO_HEADER, ALL_LANGUAGES},

#define LANGBUILTIN(ID, TYPE, ATTRS, LANGS)                                    \

  {#ID, TYPE, ATTRS, nullptr, HeaderDesc::NO_HEADER, LANGS},

#define LIBBUILTIN(ID, TYPE, ATTRS, HEADER, LANGS)                             \

  {#ID, TYPE, ATTRS, nullptr, HeaderDesc::HEADER, LANGS},

#include "clang/Basic/Builtins.def"

};

const Builtin::Info &Builtin::Context::getRecord(unsigned ID) const {

  if (ID < Builtin::FirstTSBuiltin)

    return BuiltinInfo[ID];

  assert(((ID - Builtin::FirstTSBuiltin) <

          (TSRecords.size() + AuxTSRecords.size())) &&

         "Invalid builtin ID!");

  if (isAuxBuiltinID(ID))

    return AuxTSRecords[getAuxBuiltinID(ID) - Builtin::FirstTSBuiltin];

  return TSRecords[ID - Builtin::FirstTSBuiltin];

}

void Builtin::Context::InitializeTarget(const TargetInfo &Target,

                                        const TargetInfo *AuxTarget) {

  assert(TSRecords.empty() && "Already initialized target?");

  TSRecords = Target.getTargetBuiltins();

  if (AuxTarget)

    AuxTSRecords = AuxTarget->getTargetBuiltins();

}

bool Builtin::Context::isBuiltinFunc(llvm::StringRef FuncName) {

  bool InStdNamespace = FuncName.consume_front("std-");

  for (unsigned i = Builtin::NotBuiltin + 1; i != Builtin::FirstTSBuiltin;

       ++i) {

    if (FuncName.equals(BuiltinInfo[i].Name) &&

        (bool)strchr(BuiltinInfo[i].Attributes, 'z') == InStdNamespace)

      return strchr(BuiltinInfo[i].Attributes, 'f') != nullptr;

  }

  return false;

}

/// Is this builtin supported according to the given language options?

static bool builtinIsSupported(const Builtin::Info &BuiltinInfo,

                               const LangOptions &LangOpts) {

  /* Builtins Unsupported */

  if (LangOpts.NoBuiltin && strchr(BuiltinInfo.Attributes, 'f') != nullptr)

    return false;

  /* CorBuiltins Unsupported */

  if (!LangOpts.Coroutines && (BuiltinInfo.Langs & COR_LANG))

    return false;

  /* MathBuiltins Unsupported */

  if (LangOpts.NoMathBuiltin && BuiltinInfo.Header.ID == HeaderDesc::MATH_H)

    return false;

  /* GnuMode Unsupported */

  if (!LangOpts.GNUMode && (BuiltinInfo.Langs & GNU_LANG))

    return false;

  /* MSMode Unsupported */

  if (!LangOpts.MicrosoftExt && (BuiltinInfo.Langs & MS_LANG))

    return false;

  /* ObjC Unsupported */

  if (!LangOpts.ObjC && BuiltinInfo.Langs == OBJC_LANG)

    return false;

  /* OpenCLC Unsupported */

  if (!LangOpts.OpenCL && (BuiltinInfo.Langs & ALL_OCL_LANGUAGES))

    return false;

  /* OopenCL GAS Unsupported */

  if (!LangOpts.OpenCLGenericAddressSpace && (BuiltinInfo.Langs & OCL_GAS))

    return false;

  /* OpenCL Pipe Unsupported */

  if (!LangOpts.OpenCLPipes && (BuiltinInfo.Langs & OCL_PIPE))

    return false;

  // Device side enqueue is not supported until OpenCL 2.0. In 2.0 and higher

  // support is indicated with language option for blocks.

  /* OpenCL DSE Unsupported */

  if ((LangOpts.getOpenCLCompatibleVersion() < 200 || !LangOpts.Blocks) &&

      (BuiltinInfo.Langs & OCL_DSE))

    return false;

  /* OpenMP Unsupported */

  if (!LangOpts.OpenMP && BuiltinInfo.Langs == OMP_LANG)

    return false;

  /* CUDA Unsupported */

  if (!LangOpts.CUDA && BuiltinInfo.Langs == CUDA_LANG)

    return false;

  /* CPlusPlus Unsupported */

  if (!LangOpts.CPlusPlus && BuiltinInfo.Langs == CXX_LANG)

    return false;

  return true;

}

/// initializeBuiltins - Mark the identifiers for all the builtins with their

/// appropriate builtin ID # and mark any non-portable builtin identifiers as

/// such.

void Builtin::Context::initializeBuiltins(IdentifierTable &Table,

                                          const LangOptions& LangOpts) {

  // Step #1: mark all target-independent builtins with their ID's.

  for (unsigned i = Builtin::NotBuiltin+1; i != Builtin::FirstTSBuiltin; ++i)

    if (builtinIsSupported(BuiltinInfo[i], LangOpts)) {

      Table.get(BuiltinInfo[i].Name).setBuiltinID(i);

    }

  // Step #2: Register target-specific builtins.

  for (unsigned i = 0, e = TSRecords.size(); i != e; ++i)

    if (builtinIsSupported(TSRecords[i], LangOpts))

      Table.get(TSRecords[i].Name).setBuiltinID(i + Builtin::FirstTSBuiltin);

  // Step #3: Register target-specific builtins for AuxTarget.

  for (unsigned i = 0, e = AuxTSRecords.size(); i != e; ++i)

    Table.get(AuxTSRecords[i].Name)

        .setBuiltinID(i + Builtin::FirstTSBuiltin + TSRecords.size());

  // Step #4: Unregister any builtins specified by -fno-builtin-foo.

  for (llvm::StringRef Name : LangOpts.NoBuiltinFuncs) {

    bool InStdNamespace = Name.consume_front("std-");

    auto NameIt = Table.find(Name);

    if (NameIt != Table.end()) {

      unsigned ID = NameIt->second->getBuiltinID();

      if (ID != Builtin::NotBuiltin && isPredefinedLibFunction(ID) &&

          isInStdNamespace(ID) == InStdNamespace) {

        NameIt->second->clearBuiltinID();

      }

    }

  }

}

unsigned Builtin::Context::getRequiredVectorWidth(unsigned ID) const {

  const char *WidthPos = ::strchr(getRecord(ID).Attributes, 'V');

  if (!WidthPos)

    return 0;

  ++WidthPos;

  assert(*WidthPos == ':' &&

         "Vector width specifier must be followed by a ':'");

  ++WidthPos;

  char *EndPos;

  unsigned Width = ::strtol(WidthPos, &EndPos, 10);

  assert(*EndPos == ':' && "Vector width specific must end with a ':'");

  return Width;

}

bool Builtin::Context::isLike(unsigned ID, unsigned &FormatIdx,

                              bool &HasVAListArg, const char *Fmt) const {

  assert(Fmt && "Not passed a format string");

  assert(::strlen(Fmt) == 2 &&

         "Format string needs to be two characters long");

  assert(::toupper(Fmt[0]) == Fmt[1] &&

         "Format string is not in the form \"xX\"");

  const char *Like = ::strpbrk(getRecord(ID).Attributes, Fmt);

  if (!Like)

    return false;

  HasVAListArg = (*Like == Fmt[1]);

  ++Like;

  assert(*Like == ':' && "Format specifier must be followed by a ':'");

  ++Like;

  assert(::strchr(Like, ':') && "Format specifier must end with a ':'");

  FormatIdx = ::strtol(Like, nullptr, 10);

  return true;

}

bool Builtin::Context::isPrintfLike(unsigned ID, unsigned &FormatIdx,

                                    bool &HasVAListArg) {

  return isLike(ID, FormatIdx, HasVAListArg, "pP");

}

bool Builtin::Context::isScanfLike(unsigned ID, unsigned &FormatIdx,

                                   bool &HasVAListArg) {

  return isLike(ID, FormatIdx, HasVAListArg, "sS");

}

bool Builtin::Context::performsCallback(unsigned ID,

                                        SmallVectorImpl<int> &Encoding) const {

  const char *CalleePos = ::strchr(getRecord(ID).Attributes, 'C');

  if (!CalleePos)

    return false;

  ++CalleePos;

  assert(*CalleePos == '<' &&

         "Callback callee specifier must be followed by a '<'");

  ++CalleePos;

  char *EndPos;

  int CalleeIdx = ::strtol(CalleePos, &EndPos, 10);

  assert(CalleeIdx >= 0 && "Callee index is supposed to be positive!");

  Encoding.push_back(CalleeIdx);

  while (*EndPos == ',') {

    const char *PayloadPos = EndPos + 1;

    int PayloadIdx = ::strtol(PayloadPos, &EndPos, 10);

    Encoding.push_back(PayloadIdx);

  }

  assert(*EndPos == '>' && "Callback callee specifier must end with a '>'");

  return true;

}

bool Builtin::Context::canBeRedeclared(unsigned ID) const {

  return ID == Builtin::NotBuiltin || ID == Builtin::BI__va_start ||

         ID == Builtin::BI__builtin_assume_aligned ||

         (!hasReferenceArgsOrResult(ID) && !hasCustomTypechecking(ID)) ||

         isInStdNamespace(ID);

}

bool Builtin::evaluateRequiredTargetFeatures(

    StringRef RequiredFeatures, const llvm::StringMap<bool> &TargetFetureMap) {

  // Return true if the builtin doesn't have any required features.

  if (RequiredFeatures.empty())

    return true;

  assert(!RequiredFeatures.contains(' ') && "Space in feature list");

  TargetFeatures TF(TargetFetureMap);

  return TF.hasRequiredFeatures(RequiredFeatures);

}