Support Compiler Argument Trait AB Experiment

[kuchungmsft]

• Depends on cpptools' update to provide ProjectContextResult.
• Send "standardVersion" trait in completion prompt by default.
• Added the following new traits
  • intelliSenseDisclaimer: compiler information disclaimer.
  • intelliSenseDisclaimerBeginning: to note the beginning of IntelliSense information.
  • compilerArguments: a list of compiler command arguments that could affect Copilot generating completions.
  • directAsks: direct asking Copilot to do something instead of providing an argument.
  • intelliSenseDisclaimerEnd: to note the end of IntelliSense information.
• A/B Experimental flags
  • copilotcppTraits: deprecated, no longer used.
  • copilotcppExcludeTraits:: deprecated, no longer used.
  • copilotcppIncludeTraits: string array to include individual trait, i.e., compilerArguments.
  • copilotcppMsvcCompilerArgumentFilter: map of regex string to absence prompt for MSVC.
  • copilotcppClangCompilerArgumentFilter: map of regex string to absence prompt for Clang.
  • copilotcppGccCompilerArgumentFilter: map of regex string to absence prompt for GCC.
  • copilotcppCompilerArgumentDirectAskMap: map of argument to prompt.

[sean-mcmanus]

I'm approving, but I haven't been able to test it out and you should probably get another approver.

[benmcmorran]

Pulling this down to test locally now and then I expect to be able to sign off.

[sean-mcmanus]

I left some comments, but I don't know if they need to be addressed or not.

[sean-mcmanus]

@benmcmorran Were you done reviewing? I wanted to get this in on Monday.

[benmcmorran]

@sean-mcmanus Yes, changes look good to me.

[kuchungmsft]

@sean-mcmanus I need to make some changes for the following requirements.

• If none of the MSVC /EHxx is provided, it means that exception handling is disabled. We need to be able to provide a prompt text to Copilot in such case.
• A/B experiments cannot share feature flags, I need to make it so that compiler argument experiment won't be affected by the feature flags(copilotcppExcludeTraits, copilotcppTraits) used in language standard trait experiment.

[sean-mcmanus]

• If none of the MSVC /EHxx is provided, it means that exception handling is disabled. We need to be able to provide a prompt text to Copilot in such case.

@kuchungmsft I don't understand -- exception handling is enabled by default with MSVC (/EHsc is the default).

[kuchungmsft]

• If none of the MSVC /EHxx is provided, it means that exception handling is disabled. We need to be able to provide a prompt text to Copilot in such case.

@kuchungmsft I don't understand -- exception handling is enabled by default with MSVC (/EHsc is the default).

If you don't specify any /EH arguments, it's disabled, see the following.

[sean-mcmanus]

@kuchungmsft FYI, clang-cl.exe isn't correctly handled -- the compiler is reported as Clang, but the args it excepts are normally msvc args like /DFOO=1 instead of -DFOO=1, but it also accepts clang args via -Xclang <arg>...I'm not sure what priority that is, but it seems like that could be dealt with in a potential follow up.

Oh....but we're not even telling Copilot that clang-cl is being used...hmm...?

[kuchungmsft]

@kuchungmsft FYI, clang-cl.exe isn't correctly handled -- the compiler is reported as Clang, but the args it excepts are normally msvc args like /DFOO=1 instead of -DFOO=1, but it also accepts clang args via -Xclang <arg>...I'm not sure what priority that is, but it seems like that could be dealt with in a potential follow up.

Oh....but we're not even telling Copilot that clang-cl is being used...hmm...?

We can have regex strings to filter "/GR-", "-GR-", "-fno-rtti" for Clang compiler and map those arguments to prompt text like "Do not use dynamic_cast". We'll AB with prompt text first without raw argument values.