[clang][Windows]Ignore Options '/d1nodatetime' and '/d1import_no_registry'

[Qfrost911]

Summary

Using clang and VS to build Windows Kernel Driver, two errors will be raised

1>clang-cl : error : no such file or directory: '/d1nodatetime'
1>clang-cl : error : no such file or directory: '/d1import_no_registry'

In the patch, I ignore these options in order to build windows driver under visual studio.

[thieta]

I tried to look up what these options do exactly - but they don't seem to be documented.

/d1nodatetime seems like an option that should be implemented instead of just ignored since it can have real reproducible problems not being there.

Do you know what /d1import_no_registry actually does?

I think we can ignore options that are not applicable in clang-cl, but I think if there are options that expect to change something, it's probably better to fail than to silently accept them.

[Qfrost911]

Yes, these options are not documented, so I think they can be ignored. If they are important options for windows driver, why MSVC didn't document them. And, the windows driver run perfectly even if I ignore these two options.

Moreover, there are lots of options which do nothing were defined in clang/Options.td and lld/COFF/Options.td, such as "kernel", "pdbcompress" etc., in order to be compatible with MSVC and other environment.

[hans]

I hadn't seen /d1 flags before. I suppose they relate to preprocessor stuff as opposed to /d2 flags.

I think the "Unsupported" section below may be better for these. In that case clang-cl will parse the option and warn that it's ignoring it. On line 6931 there's a catch-all for all flags starting with "d2". Perhaps we should add one for "d1" too?

Also, please add these to the "Unsupported but parsed options" tests in clang/test/Driver/cl-options.c

[Qfrost911]

Ok, I updated this patch.

[hans]

Looks great, thanks!

Do you have commit access, or would you like someone to commit this for you?

[thieta]

Makes sense they are not documented and we probably can ignore them in that case!

[efriedma]

FYI, there's some discussion of /d1nodatetime floating around, even though it isn't formally documented: it disables the definition of the __DATE__, __TIME__, and __TIMESTAMP__ macros.

(No idea about d1import_no_registry, though.)

[aganea]

In D139167#3967123, @efriedma wrote:

FYI, there's some discussion of /d1nodatetime floating around, even though it isn't formally documented: it disables the definition of the __DATE__, __TIME__, and __TIMESTAMP__ macros.

(No idea about d1import_no_registry, though.)

Those two options were introduced (I believe) along with the cl flag /experimental:deterministic (they actually alias to that flag, like -cc1 flags do in Clang). /d1import_no_registry simply adds this attribute to all #import directives, to make them deterministic.

[hans]

I see this landed in https://github.com/llvm/llvm-project/commit/4178671b2ed3d Thanks!

clang/include/clang/Driver/Options.td

 
 def _SLASH_await : CLFlag<"await">;
 def _SLASH_await_COLON : CLJoined<"await:">;
 def _SLASH_constexpr : CLJoined<"constexpr:">;
 def _SLASH_AI : CLJoinedOrSeparate<"AI">;
 def _SLASH_Bt : CLFlag<"Bt">;
 def _SLASH_Bt_plus : CLFlag<"Bt+">;
 def _SLASH_clr : CLJoined<"clr">;
+def _SLASH_d1 : CLJoined<"d1">;
 def _SLASH_d2 : CLJoined<"d2">;
 def _SLASH_doc : CLJoined<"doc">;
 def _SLASH_experimental : CLJoined<"experimental:">;
 def _SLASH_exportHeader : CLFlag<"exportHeader">;
 def _SLASH_external : CLJoined<"external:">;
 def _SLASH_favor : CLJoined<"favor">;
 def _SLASH_fsanitize_address_use_after_return : CLJoined<"fsanitize-address-use-after-return">;
 def _SLASH_fno_sanitize_address_vcasan_lib : CLJoined<"fno-sanitize-address-vcasan-lib">;

clang/test/Driver/cl-options.c

 // RUN:     /await \
 // RUN:     /await:strict \
 // RUN:     /constexpr:depth1000 /constexpr:backtrace1000 /constexpr:steps1000 \
 // RUN:     /AIfoo \
 // RUN:     /AI foo_does_not_exist \
 // RUN:     /Bt \
 // RUN:     /Bt+ \
 // RUN:     /clr:pure \
+// RUN:     /d1import_no_registry \
+// RUN:     /d1nodatetime \
 // RUN:     /d2FH4 \
 // RUN:     /docname \
 // RUN:     /experimental:external \
 // RUN:     /experimental:module \
 // RUN:     /experimental:preprocessor \
 // RUN:     /exportHeader /headerName:foo \
 // RUN:     /external:anglebrackets \
 // RUN:     /external:env:var \