[Windows] Simplify WindowsSupport.h

Sink Windows version detection code from WindowsSupport.h to Path.inc.
These functions don't need to be inlined. I randomly picked Process.inc
for the Windows version helpers, since that's the most related file.

Sink MakeErrMsg to Program.inc since it's the main client.

Move those functions into the llvm namespace, and delete the scoped
handle copy and assignment operators.

Reviewers: zturner, aganea

Differential Revision: https://reviews.llvm.org/D54182

llvm-svn: 346280

1 files changed, 24 insertions, 0 deletions

diff --git a/llvm/lib/Support/Windows/Process.inc b/llvm/lib/Support/Windows/Process.inc
index ce646d63609..2b2d7923143 100644
--- a/llvm/lib/Support/Windows/Process.inc
+++ b/llvm/lib/Support/Windows/Process.inc
@@ -460,3 +460,27 @@ unsigned Process::GetRandomNumber() {
     ReportLastErrorFatal("Could not generate a random number");
   return Ret;
 }
+
+typedef NTSTATUS(WINAPI* RtlGetVersionPtr)(PRTL_OSVERSIONINFOW);
+#define STATUS_SUCCESS ((NTSTATUS)0x00000000L)
+
+llvm::VersionTuple llvm::GetWindowsOSVersion() {
+  HMODULE hMod = ::GetModuleHandleW(L"ntdll.dll");
+  if (hMod) {
+    auto getVer = (RtlGetVersionPtr)::GetProcAddress(hMod, "RtlGetVersion");
+    if (getVer) {
+      RTL_OSVERSIONINFOEXW info{};
+      info.dwOSVersionInfoSize = sizeof(info);
+      if (getVer((PRTL_OSVERSIONINFOW)&info) == STATUS_SUCCESS) {
+        return llvm::VersionTuple(info.dwMajorVersion, info.dwMinorVersion, 0,
+                                  info.dwBuildNumber);
+      }
+    }
+  }
+  return llvm::VersionTuple(0, 0, 0, 0);
+}
+
+bool llvm::RunningWindows8OrGreater() {
+  // Windows 8 is version 6.2, service pack 0.
+  return GetWindowsOSVersion() >= llvm::VersionTuple(6, 2, 0, 0);
+}