diff --git a/lib/Lex/HeaderMap.cpp b/lib/Lex/HeaderMap.cpp
index 7dc0491..9be7b03 100644
--- a/lib/Lex/HeaderMap.cpp
+++ b/lib/Lex/HeaderMap.cpp
@@ -18,7 +18,6 @@
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
-#include <cctype>
 #include <cstdio>
 using namespace clang;
 
diff --git a/lib/Lex/LiteralSupport.cpp b/lib/Lex/LiteralSupport.cpp
index b6cc599..91da822 100644
--- a/lib/Lex/LiteralSupport.cpp
+++ b/lib/Lex/LiteralSupport.cpp
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Lex/LiteralSupport.h"
+#include "clang/Basic/CharInfo.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Lex/LexDiagnostic.h"
 #include "clang/Lex/Preprocessor.h"
@@ -128,7 +129,7 @@
     break;
   case 'x': { // Hex escape.
     ResultChar = 0;
-    if (ThisTokBuf == ThisTokEnd || !isxdigit(*ThisTokBuf)) {
+    if (ThisTokBuf == ThisTokEnd || !isHexDigit(*ThisTokBuf)) {
       if (Diags)
         Diag(Diags, Features, Loc, ThisTokBegin, EscapeBegin, ThisTokBuf,
              diag::err_hex_escape_no_digits) << "x";
@@ -197,7 +198,7 @@
     if (Diags == 0)
       break;
 
-    if (isgraph(ResultChar))
+    if (isPrintable(ResultChar))
       Diag(Diags, Features, Loc, ThisTokBegin, EscapeBegin, ThisTokBuf,
            diag::ext_unknown_escape)
         << std::string(1, ResultChar);
@@ -224,7 +225,7 @@
   // Skip the '\u' char's.
   ThisTokBuf += 2;
 
-  if (ThisTokBuf == ThisTokEnd || !isxdigit(*ThisTokBuf)) {
+  if (ThisTokBuf == ThisTokEnd || !isHexDigit(*ThisTokBuf)) {
     if (Diags)
       Diag(Diags, Features, Loc, ThisTokBegin, UcnBegin, ThisTokBuf,
            diag::err_hex_escape_no_digits) << StringRef(&ThisTokBuf[-1], 1);
@@ -459,8 +460,7 @@
   // and FP constants (specifically, the 'pp-number' regex), and assumes that
   // the byte at "*end" is both valid and not part of the regex.  Because of
   // this, it doesn't have to check for 'overscan' in various places.
-  assert(!isalnum(*ThisTokEnd) && *ThisTokEnd != '.' && *ThisTokEnd != '_' &&
-         "Lexer didn't maximally munch?");
+  assert(!isPreprocessingNumberBody(*ThisTokEnd) && "didn't maximally munch?");
 
   s = DigitsBegin = ThisTokBegin;
   saw_exponent = false;
@@ -483,7 +483,7 @@
     s = SkipDigits(s);
     if (s == ThisTokEnd) {
       // Done.
-    } else if (isxdigit(*s) && !(*s == 'e' || *s == 'E')) {
+    } else if (isHexDigit(*s) && !(*s == 'e' || *s == 'E')) {
       PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s - ThisTokBegin),
               diag::err_invalid_decimal_digit) << StringRef(s, 1);
       hadError = true;
@@ -635,7 +635,7 @@
   s++;
 
   // Handle a hex number like 0x1234.
-  if ((*s == 'x' || *s == 'X') && (isxdigit(s[1]) || s[1] == '.')) {
+  if ((*s == 'x' || *s == 'X') && (isHexDigit(s[1]) || s[1] == '.')) {
     s++;
     radix = 16;
     DigitsBegin = s;
@@ -694,7 +694,7 @@
     s = SkipBinaryDigits(s);
     if (s == ThisTokEnd) {
       // Done.
-    } else if (isxdigit(*s)) {
+    } else if (isHexDigit(*s)) {
       PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin),
               diag::err_invalid_binary_digit) << StringRef(s, 1);
       hadError = true;
@@ -714,7 +714,7 @@
 
   // If we have some other non-octal digit that *is* a decimal digit, see if
   // this is part of a floating point number like 094.123 or 09e1.
-  if (isdigit(*s)) {
+  if (isDigit(*s)) {
     const char *EndDecimal = SkipDigits(s);
     if (EndDecimal[0] == '.' || EndDecimal[0] == 'e' || EndDecimal[0] == 'E') {
       s = EndDecimal;
@@ -724,7 +724,7 @@
 
   // If we have a hex digit other than 'e' (which denotes a FP exponent) then
   // the code is using an incorrect base.
-  if (isxdigit(*s) && *s != 'e' && *s != 'E') {
+  if (isHexDigit(*s) && *s != 'e' && *s != 'E') {
     PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, s-ThisTokBegin),
             diag::err_invalid_octal_digit) << StringRef(s, 1);
     hadError = true;
diff --git a/lib/Lex/ModuleMap.cpp b/lib/Lex/ModuleMap.cpp
index 2f40e24..1ceed54 100644
--- a/lib/Lex/ModuleMap.cpp
+++ b/lib/Lex/ModuleMap.cpp
@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 #include "clang/Lex/ModuleMap.h"
+#include "clang/Basic/CharInfo.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/FileManager.h"
@@ -107,26 +108,15 @@
   if (Name.empty())
     return Name;
 
-  // Check whether the filename is already an identifier; this is the common
-  // case.
-  bool isIdentifier = true;
-  for (unsigned I = 0, N = Name.size(); I != N; ++I) {
-    if (isalpha(Name[I]) || Name[I] == '_' || (isdigit(Name[I]) && I > 0))
-      continue;
-
-    isIdentifier = false;
-    break;
-  }
-
-  if (!isIdentifier) {
+  if (!isValidIdentifier(Name)) {
     // If we don't already have something with the form of an identifier,
     // create a buffer with the sanitized name.
     Buffer.clear();
-    if (isdigit(Name[0]))
+    if (isDigit(Name[0]))
       Buffer.push_back('_');
     Buffer.reserve(Buffer.size() + Name.size());
     for (unsigned I = 0, N = Name.size(); I != N; ++I) {
-      if (isalnum(Name[I]) || isspace(Name[I]))
+      if (isIdentifierBody(Name[I]))
         Buffer.push_back(Name[I]);
       else
         Buffer.push_back('_');
diff --git a/lib/Lex/PPDirectives.cpp b/lib/Lex/PPDirectives.cpp
index 3356637..c8e1f4f 100644
--- a/lib/Lex/PPDirectives.cpp
+++ b/lib/Lex/PPDirectives.cpp
@@ -790,7 +790,7 @@
   // here.
   Val = 0;
   for (unsigned i = 0; i != ActualLength; ++i) {
-    if (!isdigit(DigitTokBegin[i])) {
+    if (!isDigit(DigitTokBegin[i])) {
       PP.Diag(PP.AdvanceToTokenCharacter(DigitTok.getLocation(), i),
               diag::err_pp_line_digit_sequence);
       PP.DiscardUntilEndOfDirective();