[Driver] Fix default MSVC version setting for -fms-compatibilty-version (#4165)

mdtoguchi · web-flow · commit dc0f7ec84aec · 2021-07-24T09:38:52.000+03:00
The input for -fms-compatibilty-version is expected to be of format:
Major[.Minor[.Micro[.Build]]]
Minor can only be 2 digits, Micro can only be 5, and 'build' is ignored.
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4639,7 +4639,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                                              MSVT.getAsString()));
       else {
         const char *LowestMSVCSupported =
-            "191025017"; // VS2017 v15.0 (initial release)
+            "19.10.25017"; // VS2017 v15.0 (initial release)
         CmdArgs.push_back(Args.MakeArgString(
             Twine("-fms-compatibility-version=") + LowestMSVCSupported));
       }

Original file line number	Diff line number	Diff line change
`@@ -4639,7 +4639,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,`
`4639`	`4639`	`MSVT.getAsString()));`
`4640`	`4640`	`else {`
`4641`	`4641`	`const char *LowestMSVCSupported =`
`4642`		`- "191025017"; // VS2017 v15.0 (initial release)`
	`4642`	`+ "19.10.25017"; // VS2017 v15.0 (initial release)`
`4643`	`4643`	`CmdArgs.push_back(Args.MakeArgString(`
`4644`	`4644`	`Twine("-fms-compatibility-version=") + LowestMSVCSupported));`
`4645`	`4645`	`}`