r222564 - MS ABI: Mangle char16_t and char32_t string literals

[Richard Smith]

Looks like MSVC also supports u8 string literals.

On Fri, Nov 21, 2014 at 11:57 AM, David Majnemer <david.majnemer at gmail.com>
wrote:

> 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?$AA@"
> +const char32_t *U32Literal = U"hi";
> +// CHECK: @"\01??_C at _0M@GFNAJIPG
> @h?$AA?$AA?$AAi?$AA?$AA?$AA?$AA?$AA?$AA?$AA@"
>
>
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