text: //===- BuildLibCalls.cpp - Utility builder for libcalls -------------------===//
  //
  //                     The LLVM Compiler Infrastructure
  //
  // This file is distributed under the University of Illinois Open Source
  // License. See LICENSE.TXT for details.
  //
  //===----------------------------------------------------------------------===//
  //
  // This file implements some functions that will create standard C libcalls.
  //
  //===----------------------------------------------------------------------===//
  
  #include "llvm/Transforms/Utils/BuildLibCalls.h"
  #include "llvm/ADT/SmallString.h"
  #include "llvm/ADT/Statistic.h"
  #include "llvm/Analysis/TargetLibraryInfo.h"
  #include "llvm/IR/Constants.h"
  #include "llvm/IR/DataLayout.h"
  #include "llvm/IR/Function.h"
  #include "llvm/IR/IRBuilder.h"
  #include "llvm/IR/Intrinsics.h"
  #include "llvm/IR/LLVMContext.h"
  #include "llvm/IR/Module.h"
  #include "llvm/IR/Type.h"
  
  using namespace llvm;
  
  #define DEBUG_TYPE "build-libcalls"
  
  //- Infer Attributes ---------------------------------------------------------//
  
  STATISTIC(NumReadNone, "Number of functions inferred as readnone");
  STATISTIC(NumReadOnly, "Number of functions inferred as readonly");
  STATISTIC(NumArgMemOnly, "Number of functions inferred as argmemonly");
  STATISTIC(NumNoUnwind, "Number of functions inferred as nounwind");
  STATISTIC(NumNoCapture, "Number of arguments inferred as nocapture");
  STATISTIC(NumReadOnlyArg, "Number of arguments inferred as readonly");
  STATISTIC(NumNoAlias, "Number of function returns inferred as noalias");
  STATISTIC(NumNonNull, "Number of function returns inferred as nonnull returns");
  
  static bool setDoesNotAccessMemory(Function &F) {
    if (F.doesNotAccessMemory())
      return false;
    F.setDoesNotAccessMemory();
    ++NumReadNone;
    return true;
  }
  
  static bool setOnlyReadsMemory(Function &F) {
    if (F.onlyReadsMemory())
      return false;
    F.setOnlyReadsMemory();
    ++NumReadOnly;
    return true;
  }
  
  static bool setOnlyAccessesArgMemory(Function &F) {
    if (F.onlyAccessesArgMemory())
      return false;
    F.setOnlyAccessesArgMemory();
    ++NumArgMemOnly;
    return true;
  }
  
  static bool setDoesNotThrow(Function &F) {
    if (F.doesNotThrow())
      return false;
    F.setDoesNotThrow();
    ++NumNoUnwind;
    return true;
  }
  
  static bool setRetDoesNotAlias(Function &F) {
    if (F.hasAttribute(AttributeList::ReturnIndex, Attribute::NoAlias))
      return false;
    F.addAttribute(AttributeList::ReturnIndex, Attribute::NoAlias);
    ++NumNoAlias;
    return true;
  }
  
  static bool setDoesNotCapture(Function &F, unsigned ArgNo) {
    if (F.hasParamAttribute(ArgNo, Attribute::NoCapture))
      return false;
    F.addParamAttr(ArgNo, Attribute::NoCapture);
    ++NumNoCapture;
    return true;
  }
  
  static bool setOnlyReadsMemory(Function &F, unsigned ArgNo) {
    if (F.hasParamAttribute(ArgNo, Attribute::ReadOnly))
      return false;
    F.addParamAttr(ArgNo, Attribute::ReadOnly);
    ++NumReadOnlyArg;
    return true;
  }
  
  static bool setRetNonNull(Function &F) {
    assert(F.getReturnType()->isPointerTy() &&
           "nonnull applies only to pointers");
    if (F.hasAttribute(AttributeList::ReturnIndex, Attribute::NonNull))
      return false;
    F.addAttribute(AttributeList::ReturnIndex, Attribute::NonNull);
    ++NumNonNull;
    return true;
  }
  
  bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
    LibFunc TheLibFunc;
    if (!(TLI.getLibFunc(F, TheLibFunc) && TLI.has(TheLibFunc)))
      return false;
  
    bool Changed = false;
    switch (TheLibFunc) {
    case LibFunc_strlen:
    case LibFunc_wcslen:
      Changed |= setOnlyReadsMemory(F);
      Changed |= setDoesNotThrow(F);
      Changed |= setOnlyAccessesArgMemory(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_strchr:
    case LibFunc_strrchr:
      Changed |= setOnlyReadsMemory(F);
      Changed |= setDoesNotThrow(F);
      return Changed;
    case LibFunc_strtol:
    case LibFunc_strtod:
    case LibFunc_strtof:
    case LibFunc_strtoul:
    case LibFunc_strtoll:
    case LibFunc_strtold:
    case LibFunc_strtoull:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_strcpy:
    case LibFunc_stpcpy:
    case LibFunc_strcat:
    case LibFunc_strncat:
    case LibFunc_strncpy:
    case LibFunc_stpncpy:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_strxfrm:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    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: //
      Changed |= setOnlyReadsMemory(F);
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_strstr:
    case LibFunc_strpbrk:
      Changed |= setOnlyReadsMemory(F);
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_strtok:
    case LibFunc_strtok_r:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_scanf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_setbuf:
    case LibFunc_setvbuf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_strdup:
    case LibFunc_strndup:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_stat:
    case LibFunc_statvfs:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_sscanf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_sprintf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_snprintf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 2);
      Changed |= setOnlyReadsMemory(F, 2);
      return Changed;
    case LibFunc_setitimer:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setDoesNotCapture(F, 2);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_system:
      // May throw; "system" is a valid pthread cancellation point.
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_malloc:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      return Changed;
    case LibFunc_memcmp:
      Changed |= setOnlyReadsMemory(F);
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_memchr:
    case LibFunc_memrchr:
      Changed |= setOnlyReadsMemory(F);
      Changed |= setDoesNotThrow(F);
      return Changed;
    case LibFunc_modf:
    case LibFunc_modff:
    case LibFunc_modfl:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_memcpy:
    case LibFunc_mempcpy:
    case LibFunc_memccpy:
    case LibFunc_memmove:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_memcpy_chk:
      Changed |= setDoesNotThrow(F);
      return Changed;
    case LibFunc_memalign:
      Changed |= setRetDoesNotAlias(F);
      return Changed;
    case LibFunc_mkdir:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_mktime:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_realloc:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_read:
      // May throw; "read" is a valid pthread cancellation point.
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_rewind:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_rmdir:
    case LibFunc_remove:
    case LibFunc_realpath:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_rename:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_readlink:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_write:
      // May throw; "write" is a valid pthread cancellation point.
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_bcopy:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_bcmp:
      Changed |= setDoesNotThrow(F);
      Changed |= setOnlyReadsMemory(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_bzero:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_calloc:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      return Changed;
    case LibFunc_chmod:
    case LibFunc_chown:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_ctermid:
    case LibFunc_clearerr:
    case LibFunc_closedir:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_atoi:
    case LibFunc_atol:
    case LibFunc_atof:
    case LibFunc_atoll:
      Changed |= setDoesNotThrow(F);
      Changed |= setOnlyReadsMemory(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_access:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_fopen:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_fdopen:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    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:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_ferror:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F);
      return Changed;
    case LibFunc_fputc:
    case LibFunc_fstat:
    case LibFunc_frexp:
    case LibFunc_frexpf:
    case LibFunc_frexpl:
    case LibFunc_fstatvfs:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_fgets:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 2);
      return Changed;
    case LibFunc_fread:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 3);
      return Changed;
    case LibFunc_fwrite:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 3);
      // FIXME: readonly #1?
      return Changed;
    case LibFunc_fputs:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_fscanf:
    case LibFunc_fprintf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_fgetpos:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_getc:
    case LibFunc_getlogin_r:
    case LibFunc_getc_unlocked:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_getenv:
      Changed |= setDoesNotThrow(F);
      Changed |= setOnlyReadsMemory(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_gets:
    case LibFunc_getchar:
      Changed |= setDoesNotThrow(F);
      return Changed;
    case LibFunc_getitimer:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_getpwnam:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_ungetc:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_uname:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_unlink:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_unsetenv:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_utime:
    case LibFunc_utimes:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_putc:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_puts:
    case LibFunc_printf:
    case LibFunc_perror:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_pread:
      // May throw; "pread" is a valid pthread cancellation point.
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_pwrite:
      // May throw; "pwrite" is a valid pthread cancellation point.
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_putchar:
      Changed |= setDoesNotThrow(F);
      return Changed;
    case LibFunc_popen:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_pclose:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_vscanf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_vsscanf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_vfscanf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_valloc:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      return Changed;
    case LibFunc_vprintf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_vfprintf:
    case LibFunc_vsprintf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_vsnprintf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 2);
      Changed |= setOnlyReadsMemory(F, 2);
      return Changed;
    case LibFunc_open:
      // May throw; "open" is a valid pthread cancellation point.
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_opendir:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_tmpfile:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      return Changed;
    case LibFunc_times:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_htonl:
    case LibFunc_htons:
    case LibFunc_ntohl:
    case LibFunc_ntohs:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotAccessMemory(F);
      return Changed;
    case LibFunc_lstat:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_lchown:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_qsort:
      // May throw; places call through function pointer.
      Changed |= setDoesNotCapture(F, 3);
      return Changed;
    case LibFunc_dunder_strdup:
    case LibFunc_dunder_strndup:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_dunder_strtok_r:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_under_IO_getc:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_under_IO_putc:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_dunder_isoc99_scanf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_stat64:
    case LibFunc_lstat64:
    case LibFunc_statvfs64:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_dunder_isoc99_sscanf:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_fopen64:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 0);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    case LibFunc_fseeko64:
    case LibFunc_ftello64:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      return Changed;
    case LibFunc_tmpfile64:
      Changed |= setDoesNotThrow(F);
      Changed |= setRetDoesNotAlias(F);
      return Changed;
    case LibFunc_fstat64:
    case LibFunc_fstatvfs64:
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_open64:
      // May throw; "open" is a valid pthread cancellation point.
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setOnlyReadsMemory(F, 0);
      return Changed;
    case LibFunc_gettimeofday:
      // Currently some platforms have the restrict keyword on the arguments to
      // gettimeofday. To be conservative, do not add noalias to gettimeofday's
      // arguments.
      Changed |= setDoesNotThrow(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      return Changed;
    case LibFunc_Znwj: // new(unsigned int)
    case LibFunc_Znwm: // new(unsigned long)
    case LibFunc_Znaj: // new[](unsigned int)
    case LibFunc_Znam: // new[](unsigned long)
    case LibFunc_msvc_new_int: // new(unsigned int)
    case LibFunc_msvc_new_longlong: // new(unsigned long long)
    case LibFunc_msvc_new_array_int: // new[](unsigned int)
    case LibFunc_msvc_new_array_longlong: // new[](unsigned long long)
      // Operator new always returns a nonnull noalias pointer
      Changed |= setRetNonNull(F);
      Changed |= setRetDoesNotAlias(F);
      return Changed;
    //TODO: add LibFunc entries for:
    //case LibFunc_memset_pattern4:
    //case LibFunc_memset_pattern8:
    case LibFunc_memset_pattern16:
      Changed |= setOnlyAccessesArgMemory(F);
      Changed |= setDoesNotCapture(F, 0);
      Changed |= setDoesNotCapture(F, 1);
      Changed |= setOnlyReadsMemory(F, 1);
      return Changed;
    // int __nvvm_reflect(const char *)
    case LibFunc_nvvm_reflect:
      Changed |= setDoesNotAccessMemory(F);
      Changed |= setDoesNotThrow(F);
      return Changed;
  
    default:
      // FIXME: It'd be really nice to cover all the library functions we're
      // aware of here.
      return false;
    }
  }
  
  bool llvm::hasUnaryFloatFn(const TargetLibraryInfo *TLI, Type *Ty,
                             LibFunc DoubleFn, LibFunc FloatFn,
                             LibFunc LongDoubleFn) {
    switch (Ty->getTypeID()) {
    case Type::FloatTyID:
      return TLI->has(FloatFn);
    case Type::DoubleTyID:
      return TLI->has(DoubleFn);
    default:
      return TLI->has(LongDoubleFn);
    }
  }
  
  //- Emit LibCalls ------------------------------------------------------------//
  
  Value *llvm::castToCStr(Value *V, IRBuilder<> &B) {
    unsigned AS = V->getType()->getPointerAddressSpace();
    return B.CreateBitCast(V, B.getInt8PtrTy(AS), "cstr");
  }
  
  Value *llvm::emitStrLen(Value *Ptr, IRBuilder<> &B, const DataLayout &DL,
                          const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_strlen))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    LLVMContext &Context = B.GetInsertBlock()->getContext();
    Constant *StrLen = M->getOrInsertFunction("strlen", DL.getIntPtrType(Context),
                                              B.getInt8PtrTy());
    inferLibFuncAttributes(*M->getFunction("strlen"), *TLI);
    CallInst *CI = B.CreateCall(StrLen, castToCStr(Ptr, B), "strlen");
    if (const Function *F = dyn_cast<Function>(StrLen->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
  
    return CI;
  }
  
  Value *llvm::emitStrChr(Value *Ptr, char C, IRBuilder<> &B,
                          const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_strchr))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    Type *I8Ptr = B.getInt8PtrTy();
    Type *I32Ty = B.getInt32Ty();
    Constant *StrChr =
        M->getOrInsertFunction("strchr", I8Ptr, I8Ptr, I32Ty);
    inferLibFuncAttributes(*M->getFunction("strchr"), *TLI);
    CallInst *CI = B.CreateCall(
        StrChr, {castToCStr(Ptr, B), ConstantInt::get(I32Ty, C)}, "strchr");
    if (const Function *F = dyn_cast<Function>(StrChr->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
    return CI;
  }
  
  Value *llvm::emitStrNCmp(Value *Ptr1, Value *Ptr2, Value *Len, IRBuilder<> &B,
                           const DataLayout &DL, const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_strncmp))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    LLVMContext &Context = B.GetInsertBlock()->getContext();
    Value *StrNCmp = M->getOrInsertFunction("strncmp", B.getInt32Ty(),
                                            B.getInt8PtrTy(), B.getInt8PtrTy(),
                                            DL.getIntPtrType(Context));
    inferLibFuncAttributes(*M->getFunction("strncmp"), *TLI);
    CallInst *CI = B.CreateCall(
        StrNCmp, {castToCStr(Ptr1, B), castToCStr(Ptr2, B), Len}, "strncmp");
  
    if (const Function *F = dyn_cast<Function>(StrNCmp->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
  
    return CI;
  }
  
  Value *llvm::emitStrCpy(Value *Dst, Value *Src, IRBuilder<> &B,
                          const TargetLibraryInfo *TLI, StringRef Name) {
    if (!TLI->has(LibFunc_strcpy))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    Type *I8Ptr = B.getInt8PtrTy();
    Value *StrCpy = M->getOrInsertFunction(Name, I8Ptr, I8Ptr, I8Ptr);
    inferLibFuncAttributes(*M->getFunction(Name), *TLI);
    CallInst *CI =
        B.CreateCall(StrCpy, {castToCStr(Dst, B), castToCStr(Src, B)}, Name);
    if (const Function *F = dyn_cast<Function>(StrCpy->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
    return CI;
  }
  
  Value *llvm::emitStrNCpy(Value *Dst, Value *Src, Value *Len, IRBuilder<> &B,
                           const TargetLibraryInfo *TLI, StringRef Name) {
    if (!TLI->has(LibFunc_strncpy))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    Type *I8Ptr = B.getInt8PtrTy();
    Value *StrNCpy = M->getOrInsertFunction(Name, I8Ptr, I8Ptr, I8Ptr,
                                            Len->getType());
    inferLibFuncAttributes(*M->getFunction(Name), *TLI);
    CallInst *CI = B.CreateCall(
        StrNCpy, {castToCStr(Dst, B), castToCStr(Src, B), Len}, "strncpy");
    if (const Function *F = dyn_cast<Function>(StrNCpy->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
    return CI;
  }
  
  Value *llvm::emitMemCpyChk(Value *Dst, Value *Src, Value *Len, Value *ObjSize,
                             IRBuilder<> &B, const DataLayout &DL,
                             const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_memcpy_chk))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    AttributeList AS;
    AS = AttributeList::get(M->getContext(), AttributeList::FunctionIndex,
                            Attribute::NoUnwind);
    LLVMContext &Context = B.GetInsertBlock()->getContext();
    Value *MemCpy = M->getOrInsertFunction(
        "__memcpy_chk", AttributeList::get(M->getContext(), AS), B.getInt8PtrTy(),
        B.getInt8PtrTy(), B.getInt8PtrTy(), DL.getIntPtrType(Context),
        DL.getIntPtrType(Context));
    Dst = castToCStr(Dst, B);
    Src = castToCStr(Src, B);
    CallInst *CI = B.CreateCall(MemCpy, {Dst, Src, Len, ObjSize});
    if (const Function *F = dyn_cast<Function>(MemCpy->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
    return CI;
  }
  
  Value *llvm::emitMemChr(Value *Ptr, Value *Val, Value *Len, IRBuilder<> &B,
                          const DataLayout &DL, const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_memchr))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    LLVMContext &Context = B.GetInsertBlock()->getContext();
    Value *MemChr = M->getOrInsertFunction("memchr", B.getInt8PtrTy(),
                                           B.getInt8PtrTy(), B.getInt32Ty(),
                                           DL.getIntPtrType(Context));
    inferLibFuncAttributes(*M->getFunction("memchr"), *TLI);
    CallInst *CI = B.CreateCall(MemChr, {castToCStr(Ptr, B), Val, Len}, "memchr");
  
    if (const Function *F = dyn_cast<Function>(MemChr->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
  
    return CI;
  }
  
  Value *llvm::emitMemCmp(Value *Ptr1, Value *Ptr2, Value *Len, IRBuilder<> &B,
                          const DataLayout &DL, const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_memcmp))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    LLVMContext &Context = B.GetInsertBlock()->getContext();
    Value *MemCmp = M->getOrInsertFunction("memcmp", B.getInt32Ty(),
                                           B.getInt8PtrTy(), B.getInt8PtrTy(),
                                           DL.getIntPtrType(Context));
    inferLibFuncAttributes(*M->getFunction("memcmp"), *TLI);
    CallInst *CI = B.CreateCall(
        MemCmp, {castToCStr(Ptr1, B), castToCStr(Ptr2, B), Len}, "memcmp");
  
    if (const Function *F = dyn_cast<Function>(MemCmp->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
  
    return CI;
  }
  
  /// Append a suffix to the function name according to the type of 'Op'.
  static void appendTypeSuffix(Value *Op, StringRef &Name,
                               SmallString<20> &NameBuffer) {
    if (!Op->getType()->isDoubleTy()) {
        NameBuffer += Name;
  
      if (Op->getType()->isFloatTy())
        NameBuffer += 'f';
      else
        NameBuffer += 'l';
  
      Name = NameBuffer;
    }  
  }
  
  Value *llvm::emitUnaryFloatFnCall(Value *Op, StringRef Name, IRBuilder<> &B,
                                    const AttributeList &Attrs) {
    SmallString<20> NameBuffer;
    appendTypeSuffix(Op, Name, NameBuffer);
  
    Module *M = B.GetInsertBlock()->getModule();
    Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
                                           Op->getType());
    CallInst *CI = B.CreateCall(Callee, Op, Name);
  
    // The incoming attribute set may have come from a speculatable intrinsic, but
    // is being replaced with a library call which is not allowed to be
    // speculatable.
    CI->setAttributes(Attrs.removeAttribute(B.getContext(),
                                            AttributeList::FunctionIndex,
                                            Attribute::Speculatable));
    if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
  
    return CI;
  }
  
  Value *llvm::emitBinaryFloatFnCall(Value *Op1, Value *Op2, StringRef Name,
                                     IRBuilder<> &B, const AttributeList &Attrs) {
    SmallString<20> NameBuffer;
    appendTypeSuffix(Op1, Name, NameBuffer);
  
    Module *M = B.GetInsertBlock()->getModule();
    Value *Callee = M->getOrInsertFunction(Name, Op1->getType(), Op1->getType(),
                                           Op2->getType());
    CallInst *CI = B.CreateCall(Callee, {Op1, Op2}, Name);
    CI->setAttributes(Attrs);
    if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
  
    return CI;
  }
  
  Value *llvm::emitPutChar(Value *Char, IRBuilder<> &B,
                           const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_putchar))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    Value *PutChar = M->getOrInsertFunction("putchar", B.getInt32Ty(), B.getInt32Ty());
    inferLibFuncAttributes(*M->getFunction("putchar"), *TLI);
    CallInst *CI = B.CreateCall(PutChar,
                                B.CreateIntCast(Char,
                                B.getInt32Ty(),
                                /*isSigned*/true,
                                "chari"),
                                "putchar");
  
    if (const Function *F = dyn_cast<Function>(PutChar->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
    return CI;
  }
  
  Value *llvm::emitPutS(Value *Str, IRBuilder<> &B,
                        const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_puts))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    Value *PutS =
        M->getOrInsertFunction("puts", B.getInt32Ty(), B.getInt8PtrTy());
    inferLibFuncAttributes(*M->getFunction("puts"), *TLI);
    CallInst *CI = B.CreateCall(PutS, castToCStr(Str, B), "puts");
    if (const Function *F = dyn_cast<Function>(PutS->stripPointerCasts()))
      CI->setCallingConv(F->getCallingConv());
    return CI;
  }
  
  Value *llvm::emitFPutC(Value *Char, Value *File, IRBuilder<> &B,
                         const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_fputc))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    Constant *F = M->getOrInsertFunction("fputc", B.getInt32Ty(), B.getInt32Ty(),
                                         File->getType());
    if (File->getType()->isPointerTy())
      inferLibFuncAttributes(*M->getFunction("fputc"), *TLI);
    Char = B.CreateIntCast(Char, B.getInt32Ty(), /*isSigned*/true,
                           "chari");
    CallInst *CI = B.CreateCall(F, {Char, File}, "fputc");
  
    if (const Function *Fn = dyn_cast<Function>(F->stripPointerCasts()))
      CI->setCallingConv(Fn->getCallingConv());
    return CI;
  }
  
  Value *llvm::emitFPutS(Value *Str, Value *File, IRBuilder<> &B,
                         const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_fputs))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    StringRef FPutsName = TLI->getName(LibFunc_fputs);
    Constant *F = M->getOrInsertFunction(
        FPutsName, B.getInt32Ty(), B.getInt8PtrTy(), File->getType());
    if (File->getType()->isPointerTy())
      inferLibFuncAttributes(*M->getFunction(FPutsName), *TLI);
    CallInst *CI = B.CreateCall(F, {castToCStr(Str, B), File}, "fputs");
  
    if (const Function *Fn = dyn_cast<Function>(F->stripPointerCasts()))
      CI->setCallingConv(Fn->getCallingConv());
    return CI;
  }
  
  Value *llvm::emitFWrite(Value *Ptr, Value *Size, Value *File, IRBuilder<> &B,
                          const DataLayout &DL, const TargetLibraryInfo *TLI) {
    if (!TLI->has(LibFunc_fwrite))
      return nullptr;
  
    Module *M = B.GetInsertBlock()->getModule();
    LLVMContext &Context = B.GetInsertBlock()->getContext();
    StringRef FWriteName = TLI->getName(LibFunc_fwrite);
    Constant *F = M->getOrInsertFunction(
        FWriteName, DL.getIntPtrType(Context), B.getInt8PtrTy(),
        DL.getIntPtrType(Context), DL.getIntPtrType(Context), File->getType());
  
    if (File->getType()->isPointerTy())
      inferLibFuncAttributes(*M->getFunction(FWriteName), *TLI);
    CallInst *CI =
        B.CreateCall(F, {castToCStr(Ptr, B), Size,
                         ConstantInt::get(DL.getIntPtrType(Context), 1), File});
  
    if (const Function *Fn = dyn_cast<Function>(F->stripPointerCasts()))
      CI->setCallingConv(Fn->getCallingConv());
    return CI;
  }
  