Revert "Remove support for unsupported MSVC versions"

Mismatched preprocessor, I'll fix in a follow-up.

llvm-svn: 367728

llvm/include/llvm/Demangle/DemangleConfig.h

@@ -15,6 +15,13 @@
 #ifndef LLVM_DEMANGLE_COMPILER_H
 #define LLVM_DEMANGLE_COMPILER_H
 
+#ifdef _MSC_VER
+// snprintf is implemented in VS 2015
+#if _MSC_VER < 1900
+#define snprintf _snprintf_s
+#endif
+#endif
+
 #ifndef __has_feature
 #define __has_feature(x) 0
 #endif

llvm/lib/DebugInfo/PDB/DIA/DIASession.cpp

@@ -73,7 +73,13 @@ static Error LoadDIA(CComPtr<IDiaDataSource> &DiaDataSource) {
 #if !defined(_MSC_VER)
   return llvm::make_error<PDBError>(pdb_error_code::dia_failed_loading);
 #else
-  const wchar_t *msdia_dll = L"msdia140.dll";
+  const wchar_t *msdia_dll = nullptr;
+#if _MSC_VER >= 1900 && _MSC_VER < 2000
+  msdia_dll = L"msdia140.dll"; // VS2015
+#elif _MSC_VER >= 1800
+  msdia_dll = L"msdia120.dll"; // VS2013
+#else
+#error "Unknown Visual Studio version."
 #endif
 
   HRESULT HR;

llvm/lib/Support/Windows/explicit_symbols.inc

@@ -90,6 +90,12 @@
   INLINE_DEF_FLOAT_SYMBOL(tanf, 1)
   INLINE_DEF_FLOAT_SYMBOL(tanhf, 1)
 
+  // These were added in VS 2013.
+#if (1800 <= _MSC_VER && _MSC_VER < 1900)
+  INLINE_DEF_FLOAT_SYMBOL(copysignf, 2)
+  INLINE_DEF_FLOAT_SYMBOL(fminf, 2)
+  INLINE_DEF_FLOAT_SYMBOL(fmaxf, 2)
+#endif
 #undef INLINE_DEF_FLOAT_SYMBOL
 #endif