From: Eli Friedman <eli.friedman@gmail.com>
Date: Wed, 2 Nov 2011 23:06:23 +0000 (+0000)
Subject: Use native endianness for writing out character escapes to the result buffer for... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=caf1f26777c3adf2556c3af7bf9e01bd8ead17d9;p=clang

Use native endianness for writing out character escapes to the result buffer for string literal parsing.  No functional change on little-endian architectures; should fix test failures on PPC.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143585 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Lex/LiteralSupport.cpp b/lib/Lex/LiteralSupport.cpp
index b107531e14..de10c3a824 100644
--- a/lib/Lex/LiteralSupport.cpp
+++ b/lib/Lex/LiteralSupport.cpp
@@ -253,31 +253,32 @@ static void EncodeUCNEscape(const char *&ThisTokBuf, const char *ThisTokEnd,
   assert((UcnLen== 4 || UcnLen== 8) && "only ucn length of 4 or 8 supported");
 
   if (CharByteWidth == 4) {
-    // Note: our internal rep of wide char tokens is always little-endian.
-    *ResultBuf++ = (UcnVal & 0x000000FF);
-    *ResultBuf++ = (UcnVal & 0x0000FF00) >> 8;
-    *ResultBuf++ = (UcnVal & 0x00FF0000) >> 16;
-    *ResultBuf++ = (UcnVal & 0xFF000000) >> 24;
+    // FIXME: Make the type of the result buffer correct instead of
+    // using reinterpret_cast.
+    UTF32 *ResultPtr = reinterpret_cast<UTF32*>(ResultBuf);
+    *ResultPtr = UcnVal;
+    ResultBuf += 4;
     return;
   }
 
   if (CharByteWidth == 2) {
-    // Convert to UTF16.
+    // FIXME: Make the type of the result buffer correct instead of
+    // using reinterpret_cast.
+    UTF16 *ResultPtr = reinterpret_cast<UTF16*>(ResultBuf);
+
     if (UcnVal < (UTF32)0xFFFF) {
-      *ResultBuf++ = (UcnVal & 0x000000FF);
-      *ResultBuf++ = (UcnVal & 0x0000FF00) >> 8;
+      *ResultPtr = UcnVal;
+      ResultBuf += 2;
       return;
     }
+    // FIXME: We shouldn't print a diagnostic for UTF-16 mode.
     if (Diags) Diags->Report(Loc, diag::warn_ucn_escape_too_large);
 
-    typedef uint16_t UTF16;
+    // Convert to UTF16.
     UcnVal -= 0x10000;
-    UTF16 surrogate1 = 0xD800 + (UcnVal >> 10);
-    UTF16 surrogate2 = 0xDC00 + (UcnVal & 0x3FF);
-    *ResultBuf++ = (surrogate1 & 0x000000FF);
-    *ResultBuf++ = (surrogate1 & 0x0000FF00) >> 8;
-    *ResultBuf++ = (surrogate2 & 0x000000FF);
-    *ResultBuf++ = (surrogate2 & 0x0000FF00) >> 8;
+    *ResultPtr     = 0xD800 + (UcnVal >> 10);
+    *(ResultPtr+1) = 0xDC00 + (UcnVal & 0x3FF);
+    ResultBuf += 4;
     return;
   }
 
@@ -1090,11 +1091,22 @@ void StringLiteralParser::init(const Token *StringToks, unsigned NumStringToks){
                             FullSourceLoc(StringToks[i].getLocation(), SM),
                             CharByteWidth*8, Diags);
 
-        // Note: our internal rep of wide char tokens is always little-endian.
-        *ResultPtr++ = ResultChar & 0xFF;
-
-        for (unsigned i = 1, e = CharByteWidth; i != e; ++i)
-          *ResultPtr++ = ResultChar >> i*8;
+        if (CharByteWidth == 4) {
+          // FIXME: Make the type of the result buffer correct instead of
+          // using reinterpret_cast.
+          UTF32 *ResultWidePtr = reinterpret_cast<UTF32*>(ResultPtr);
+          *ResultWidePtr = ResultChar & 0xFF;
+          ResultPtr += 4;
+        } else if (CharByteWidth == 2) {
+          // FIXME: Make the type of the result buffer correct instead of
+          // using reinterpret_cast.
+          UTF16 *ResultWidePtr = reinterpret_cast<UTF16*>(ResultPtr);
+          *ResultWidePtr = ResultChar & 0xFF;
+          ResultPtr += 2;
+        } else {
+          assert(CharByteWidth == 1 && "Unexpected char width");
+          *ResultPtr++ = ResultChar & 0xFF;
+        }
       }
     }
   }