bool FunctionAttrs::inferPrototypeAttributes()

in lib/Transforms/IPO/FunctionAttrs.cpp [842:1689]

• 833 lines of code
• 384 McCabe index (conditional complexity)

bool FunctionAttrs::inferPrototypeAttributes(Function &F) {
  if (F.hasFnAttribute(Attribute::OptimizeNone))
    return false;

  FunctionType *FTy = F.getFunctionType();
  LibFunc::Func TheLibFunc;
  if (!(TLI->getLibFunc(F.getName(), TheLibFunc) && TLI->has(TheLibFunc)))
    return false;

  switch (TheLibFunc) {
  case LibFunc::strlen:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setOnlyReadsMemory(F);
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::strchr:
  case LibFunc::strrchr:
    if (FTy->getNumParams() != 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isIntegerTy())
      return false;
    setOnlyReadsMemory(F);
    setDoesNotThrow(F);
    break;
  case LibFunc::strtol:
  case LibFunc::strtod:
  case LibFunc::strtof:
  case LibFunc::strtoul:
  case LibFunc::strtoll:
  case LibFunc::strtold:
  case LibFunc::strtoull:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::strcpy:
  case LibFunc::stpcpy:
  case LibFunc::strcat:
  case LibFunc::strncat:
  case LibFunc::strncpy:
  case LibFunc::stpncpy:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::strxfrm:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::strcmp: //0,1
    case LibFunc::strspn: // 0,1
    case LibFunc::strncmp: // 0,1
    case LibFunc::strcspn: //0,1
    case LibFunc::strcoll: //0,1
    case LibFunc::strcasecmp:  // 0,1
    case LibFunc::strncasecmp: // 
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setOnlyReadsMemory(F);
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::strstr:
  case LibFunc::strpbrk:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
      return false;
    setOnlyReadsMemory(F);
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::strtok:
  case LibFunc::strtok_r:
    if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::scanf:
    if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::setbuf:
  case LibFunc::setvbuf:
    if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::strdup:
  case LibFunc::strndup:
    if (FTy->getNumParams() < 1 || !FTy->getReturnType()->isPointerTy() ||
        !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::stat:
  case LibFunc::statvfs:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::sscanf:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::sprintf:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::snprintf:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(2)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 3);
    setOnlyReadsMemory(F, 3);
    break;
  case LibFunc::setitimer:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(1)->isPointerTy() ||
        !FTy->getParamType(2)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    setDoesNotCapture(F, 3);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::system:
    if (FTy->getNumParams() != 1 ||
        !FTy->getParamType(0)->isPointerTy())
      return false;
    // May throw; "system" is a valid pthread cancellation point.
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::malloc:
    if (FTy->getNumParams() != 1 ||
        !FTy->getReturnType()->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    break;
  case LibFunc::memcmp:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setOnlyReadsMemory(F);
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::memchr:
  case LibFunc::memrchr:
    if (FTy->getNumParams() != 3)
      return false;
    setOnlyReadsMemory(F);
    setDoesNotThrow(F);
    break;
  case LibFunc::modf:
  case LibFunc::modff:
  case LibFunc::modfl:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::memcpy:
  case LibFunc::memccpy:
  case LibFunc::memmove:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::memalign:
    if (!FTy->getReturnType()->isPointerTy())
      return false;
    setDoesNotAlias(F, 0);
    break;
  case LibFunc::mkdir:
    if (FTy->getNumParams() == 0 ||
        !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::mktime:
    if (FTy->getNumParams() == 0 ||
        !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::realloc:
    if (FTy->getNumParams() != 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getReturnType()->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::read:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    // May throw; "read" is a valid pthread cancellation point.
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::rewind:
    if (FTy->getNumParams() < 1 ||
        !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::rmdir:
  case LibFunc::remove:
  case LibFunc::realpath:
    if (FTy->getNumParams() < 1 ||
        !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::rename:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::readlink:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::write:
    if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
      return false;
    // May throw; "write" is a valid pthread cancellation point.
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::bcopy:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::bcmp:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setOnlyReadsMemory(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::bzero:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::calloc:
    if (FTy->getNumParams() != 2 ||
        !FTy->getReturnType()->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    break;
  case LibFunc::chmod:
  case LibFunc::chown:
    if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::ctermid:
  case LibFunc::clearerr:
  case LibFunc::closedir:
    if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::atoi:
  case LibFunc::atol:
  case LibFunc::atof:
  case LibFunc::atoll:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setOnlyReadsMemory(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::access:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::fopen:
    if (FTy->getNumParams() != 2 ||
        !FTy->getReturnType()->isPointerTy() ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::fdopen:
    if (FTy->getNumParams() != 2 ||
        !FTy->getReturnType()->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::feof:
  case LibFunc::free:
  case LibFunc::fseek:
  case LibFunc::ftell:
  case LibFunc::fgetc:
  case LibFunc::fseeko:
  case LibFunc::ftello:
  case LibFunc::fileno:
  case LibFunc::fflush:
  case LibFunc::fclose:
  case LibFunc::fsetpos:
  case LibFunc::flockfile:
  case LibFunc::funlockfile:
  case LibFunc::ftrylockfile:
    if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::ferror:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F);
    break;
  case LibFunc::fputc:
  case LibFunc::fstat:
  case LibFunc::frexp:
  case LibFunc::frexpf:
  case LibFunc::frexpl:
  case LibFunc::fstatvfs:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::fgets:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(2)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 3);
    break;
  case LibFunc::fread:
    if (FTy->getNumParams() != 4 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(3)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 4);
    break;
  case LibFunc::fwrite:
    if (FTy->getNumParams() != 4 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(3)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 4);
    break;
  case LibFunc::fputs:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::fscanf:
  case LibFunc::fprintf:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::fgetpos:
    if (FTy->getNumParams() < 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::getc:
  case LibFunc::getlogin_r:
  case LibFunc::getc_unlocked:
    if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::getenv:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setOnlyReadsMemory(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::gets:
  case LibFunc::getchar:
    setDoesNotThrow(F);
    break;
  case LibFunc::getitimer:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::getpwnam:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::ungetc:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::uname:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::unlink:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::unsetenv:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::utime:
  case LibFunc::utimes:
    if (FTy->getNumParams() != 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::putc:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::puts:
  case LibFunc::printf:
  case LibFunc::perror:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::pread:
    if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
      return false;
    // May throw; "pread" is a valid pthread cancellation point.
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::pwrite:
    if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
      return false;
    // May throw; "pwrite" is a valid pthread cancellation point.
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::putchar:
    setDoesNotThrow(F);
    break;
  case LibFunc::popen:
    if (FTy->getNumParams() != 2 ||
        !FTy->getReturnType()->isPointerTy() ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::pclose:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::vscanf:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::vsscanf:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(1)->isPointerTy() ||
        !FTy->getParamType(2)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::vfscanf:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(1)->isPointerTy() ||
        !FTy->getParamType(2)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::valloc:
    if (!FTy->getReturnType()->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    break;
  case LibFunc::vprintf:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::vfprintf:
  case LibFunc::vsprintf:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::vsnprintf:
    if (FTy->getNumParams() != 4 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(2)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 3);
    setOnlyReadsMemory(F, 3);
    break;
  case LibFunc::open:
    if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
      return false;
    // May throw; "open" is a valid pthread cancellation point.
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::opendir:
    if (FTy->getNumParams() != 1 ||
        !FTy->getReturnType()->isPointerTy() ||
        !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::tmpfile:
    if (!FTy->getReturnType()->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    break;
  case LibFunc::times:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::htonl:
  case LibFunc::htons:
  case LibFunc::ntohl:
  case LibFunc::ntohs:
    setDoesNotThrow(F);
    setDoesNotAccessMemory(F);
    break;
  case LibFunc::lstat:
    if (FTy->getNumParams() != 2 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::lchown:
    if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::qsort:
    if (FTy->getNumParams() != 4 || !FTy->getParamType(3)->isPointerTy())
      return false;
    // May throw; places call through function pointer.
    setDoesNotCapture(F, 4);
    break;
  case LibFunc::dunder_strdup:
  case LibFunc::dunder_strndup:
    if (FTy->getNumParams() < 1 ||
        !FTy->getReturnType()->isPointerTy() ||
        !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::dunder_strtok_r:
    if (FTy->getNumParams() != 3 ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::under_IO_getc:
    if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::under_IO_putc:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::dunder_isoc99_scanf:
    if (FTy->getNumParams() < 1 ||
        !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::stat64:
  case LibFunc::lstat64:
  case LibFunc::statvfs64:
    if (FTy->getNumParams() < 1 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::dunder_isoc99_sscanf:
    if (FTy->getNumParams() < 1 ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    setOnlyReadsMemory(F, 2);
    break;
#if 0 // HLSL Change Starts - Exclude potentially duplicate 64bit versions
  case LibFunc::fopen64:
    if (FTy->getNumParams() != 2 ||
        !FTy->getReturnType()->isPointerTy() ||
        !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    setOnlyReadsMemory(F, 1);
    setOnlyReadsMemory(F, 2);
    break;
  case LibFunc::fseeko64:
  case LibFunc::ftello64:
    if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    break;
  case LibFunc::tmpfile64:
    if (!FTy->getReturnType()->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotAlias(F, 0);
    break;
#endif // HLSL Change Ends - Exclude potentially duplicate 64bit versions
  case LibFunc::fstat64:
  case LibFunc::fstatvfs64:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
      return false;
    setDoesNotThrow(F);
    setDoesNotCapture(F, 2);
    break;
  case LibFunc::open64:
    if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
      return false;
    // May throw; "open" is a valid pthread cancellation point.
    setDoesNotCapture(F, 1);
    setOnlyReadsMemory(F, 1);
    break;
  case LibFunc::gettimeofday:
    if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy() ||
        !FTy->getParamType(1)->isPointerTy())
      return false;
    // Currently some platforms have the restrict keyword on the arguments to
    // gettimeofday. To be conservative, do not add noalias to gettimeofday's
    // arguments.
    setDoesNotThrow(F);
    setDoesNotCapture(F, 1);
    setDoesNotCapture(F, 2);
    break;
  default:
    // Didn't mark any attributes.
    return false;
  }

  return true;
}