r222564 - MS ABI: Mangle char16_t and char32_t string literals

[David Majnemer]

Author: majnemer
Date: Fri Nov 21 13:57:25 2014
New Revision: 222564

URL: http://llvm.org/viewvc/llvm-project?rev=222564&view=rev
Log:
MS ABI: Mangle char16_t and char32_t string literals

We previously had support for char and wchar_t string literals.  VS 2015
added support for char16_t and char32_t.

String literals must be mangled in the MS ABI in order for them to be
deduplicated across translation units: their linker has no notion of
mergeable section.  Instead, they use the mangled name to make a COMDAT
for the string literal; the COMDAT will merge with other COMDATs in
other object files.

This allows strings in object files generated by clang to get merged
with strings in object files generated by MSVC.

Modified:
    cfe/trunk/lib/AST/MicrosoftMangle.cpp
    cfe/trunk/test/CodeGenCXX/mangle-ms-string-literals.cpp

Modified: cfe/trunk/lib/AST/MicrosoftMangle.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/MicrosoftMangle.cpp?rev=222564&r1=222563&r2=222564&view=diff
==============================================================================
--- cfe/trunk/lib/AST/MicrosoftMangle.cpp (original)
+++ cfe/trunk/lib/AST/MicrosoftMangle.cpp Fri Nov 21 13:57:25 2014
@@ -338,9 +338,7 @@ bool MicrosoftMangleContextImpl::shouldM
 
 bool
 MicrosoftMangleContextImpl::shouldMangleStringLiteral(const StringLiteral *SL) {
-  return SL->isAscii() || SL->isWide();
-  // TODO: This needs to be updated when MSVC gains support for Unicode
-  // literals.
+  return SL->isAscii() || SL->isWide() || SL->isUTF16() || SL->isUTF32();
 }
 
 void MicrosoftCXXNameMangler::mangle(const NamedDecl *D, StringRef Prefix) {
@@ -2439,14 +2437,10 @@ void MicrosoftMangleContextImpl::mangleS
   Mangler.getStream() << "\01??_C at _";
 
   // <char-type>: The "kind" of string literal is encoded into the mangled name.
-  // TODO: This needs to be updated when MSVC gains support for unicode
-  // literals.
-  if (SL->isAscii())
-    Mangler.getStream() << '0';
-  else if (SL->isWide())
+  if (SL->isWide())
     Mangler.getStream() << '1';
   else
-    llvm_unreachable("unexpected string literal kind!");
+    Mangler.getStream() << '0';
 
   // <literal-length>: The next part of the mangled name consists of the length
   // of the string.
@@ -2569,7 +2563,10 @@ void MicrosoftMangleContextImpl::mangleS
   unsigned NumCharsToMangle = std::min(32U, SL->getLength());
   for (unsigned I = 0, E = NumCharsToMangle * SL->getCharByteWidth(); I != E;
        ++I)
-    MangleByte(GetBigEndianByte(I));
+    if (SL->isWide())
+      MangleByte(GetBigEndianByte(I));
+    else
+      MangleByte(GetLittleEndianByte(I));
 
   // Encode the NUL terminator if there is room.
   if (NumCharsToMangle < 32)

Modified: cfe/trunk/test/CodeGenCXX/mangle-ms-string-literals.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/mangle-ms-string-literals.cpp?rev=222564&r1=222563&r2=222564&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/mangle-ms-string-literals.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/mangle-ms-string-literals.cpp Fri Nov 21 13:57:25 2014
@@ -719,3 +719,7 @@ const wchar_t *LongWideString = L"012345
 // CHECK: @"\01??_C at _1EK@KFPEBLPK@?$AA0?$AA1?$AA2?$AA3?$AA4?$AA5?$AA6?$AA7?$AA8?$AA9?$AA0?$AA1?$AA2?$AA3?$AA4?$AA5?$AA6?$AA7?$AA8?$AA9?$AA0?$AA1?$AA2?$AA3?$AA4?$AA5?$AA6?$AA7?$AA8?$AA9?$AAA?$AAB@"
 const wchar_t *UnicodeLiteral = L"\ud7ff";
 // CHECK: @"\01??_C at _13IIHIAFKH@?W?$PP?$AA?$AA@"
+const char16_t *U16Literal = u"hi";
+// CHECK: @"\01??_C at _05OMLEGLOC@h?$AAi?$AA?$AA?$AA@"
+const char32_t *U32Literal = U"hi";
+// CHECK: @"\01??_C at _0M@GFNAJIPG at h?$AA?$AA?$AAi?$AA?$AA?$AA?$AA?$AA?$AA?$AA@"