[Bash-autocompletion] Add support for -W<warning> and -Wno<warning>

[yamaguchi]

Summary

-W[tab] will autocomplete warnings defined in this link:
https://clang.llvm.org/docs/DiagnosticsReference.html#wweak-vtables

[ruiu]

clang/include/clang/Basic/DiagnosticIDs.h

266

Please write a function comment just like other member functions in this class.

clang/lib/Basic/DiagnosticIDs.cpp

514

res -> Res
i -> I

515

size_t is more precise than int, even though sizeof(DiagGroupNames) in reality fits in an int.

516–517

If you want to construct a string, you can do this

std::string Diag(DiagGroupNames + i + 1, DiagGroupNames[i]);

519–522

I think you can remove these temporary variables:

res.push_back("-W" + Diag);
res.push_back("-Wno" + Diag);

clang/lib/Driver/Driver.cpp

1279

Let's avoid copy: std::string -> StringRef

[teemperor]

It seems the code doesn't compile in clang because on your platform std::vector is implicitly included by some header, on clang+Arch however it isn`t (see the error at the end of https://teemperor.de/ccir/D35447).

clang/lib/Driver/Driver.cpp

1279

Could you document why we had to do it this way and can't reuse the normal flags? Maybe even add a TODO: because it would be nice project for someone to refactor this into one data structure.

[yamaguchi]

@teemperor
I forgot to include <vector> in DiagnosticIDs, thanks!

What do you mean reuse the normal flags ?
Do you think we should define these -W<warnings> in Options.td like other flags?

[teemperor]

@yamaguchi yes, the reason why we have to treat the -W... flags specially should be documented (as they're not in the OptTable as you said). E.g. something like // We have to query the -W flags manually as they're not in the OptTable. and then maybe a TODO: Find a good way to add them to OptTable instead and them remove this code..

[yamaguchi]

Update diff according to Rui and teemperor's comments.

[yamaguchi]

Add code comment.

[yamaguchi]

Fixed indent.

[teemperor]

I have a last request in my inline comment regarding the documentation, otherwise this is good to go. Nice work!

clang/include/clang/Basic/DiagnosticIDs.h

266

Let's add an example to make it clear that we want to have the command line flags here, something like this:

/// \brief Get the list of all diagnostic flags.
/// \returns A list of all diagnostics flags as they would be written in a command line invocation
///          including their `no-` variants. For example: `{"-Wempty-body", "-Wno-empty-body", ...}`

[ruiu]

LGTM

clang/lib/Driver/Driver.cpp

1283

nit: StringRef(S) -> S as S is already a StringRef.

clang/include/clang/Basic/DiagnosticIDs.h

public:
   /// argument deduction.
   ///
   /// When an error is suppressed due to SFINAE, the template argument
   /// deduction fails but no diagnostic is emitted. Certain classes of
   /// errors, such as those errors that involve C++ access control,
   /// are not SFINAE errors.
   static SFINAEResponse getDiagnosticSFINAEResponse(unsigned DiagID);
 
+  static std::vector<std::string> getDiagnosticFlags();
+
   /// \brief Get the set of all diagnostic IDs in the group with the given name.
   ///
   /// \param[out] Diags - On return, the diagnostics in the group.
   /// \returns \c true if the given group is unknown, \c false otherwise.
   bool getDiagnosticsInGroup(diag::Flavor Flavor, StringRef Group,
                              SmallVectorImpl<diag::kind> &Diags) const;
 
   /// \brief Get the set of all diagnostic IDs.

clang/lib/Basic/DiagnosticIDs.cpp

 /// enables the specified diagnostic.  If there is no -Wfoo flag that controls
 /// the diagnostic, this returns null.
 StringRef DiagnosticIDs::getWarningOptionForDiag(unsigned DiagID) {
   if (const StaticDiagInfoRec *Info = GetDiagInfo(DiagID))
     return OptionTable[Info->getOptionGroupIndex()].getName();
   return StringRef();
 }
 
+std::vector<std::string> DiagnosticIDs::getDiagnosticFlags() {
+  std::vector<std::string> res;
+  for (int i = 1; DiagGroupNames[i] != '\0';) {
+    std::string Diag =
+        std::string(StringRef(DiagGroupNames + i + 1, DiagGroupNames[i]));
+    i += DiagGroupNames[i] + 1;
+    std::string W = "-W" + Diag;
+    std::string Wno = "-Wno" + Diag;
+    res.push_back(W);
+    res.push_back(Wno);
+  }
+
+  return res;
+}
+
 /// Return \c true if any diagnostics were found in this group, even if they
 /// were filtered out due to having the wrong flavor.
 static bool getDiagnosticsInGroup(diag::Flavor Flavor,
                                   const WarningOption *Group,
                                   SmallVectorImpl<diag::kind> &Diags) {
   // An empty group is considered to be a warning group: we have empty groups
   // for GCC compatibility, and GCC does not have remarks.
   if (!Group->Members && !Group->SubGroups)

clang/lib/Driver/Driver.cpp

if (PassedFlags[0] == '#') {
       PassedFlags = PassedFlags.substr(1);
     }
 
     if (PassedFlags.find(',') == StringRef::npos) {
       // If the flag is in the form of "--autocomplete=-foo",
       // we were requested to print out all option names that start with "-foo".
       // For example, "--autocomplete=-fsyn" is expanded to "-fsyntax-only".
       SuggestedCompletions = Opts->findByPrefix(PassedFlags, DisableFlags);
+
+      for (std::string S : DiagnosticIDs::getDiagnosticFlags())
+        if (StringRef(S).startswith(PassedFlags))
+          SuggestedCompletions.push_back(S);
     } else {
       // If the flag is in the form of "--autocomplete=foo,bar", we were
       // requested to print out all option values for "-foo" that start with
       // "bar". For example,
       // "--autocomplete=-stdlib=,l" is expanded to "libc++" and "libstdc++".
       StringRef Option, Arg;
       std::tie(Option, Arg) = PassedFlags.split(',');
       SuggestedCompletions = Opts->suggestValueCompletions(Option, Arg);
     }
 

clang/test/Driver/autocomplete.c

 // RUN: %clang --autocomplete=-mthread-model, | FileCheck %s -check-prefix=MTHREADMODELALL
 // MTHREADMODELALL: posix single
 // RUN: %clang --autocomplete=-mrelocation-model, | FileCheck %s -check-prefix=MRELOCMODELALL
 // MRELOCMODELALL: dynamic-no-pic pic ropi ropi-rwpi rwpi static
 // RUN: %clang --autocomplete=-mrelocation-mode | FileCheck %s -check-prefix=MRELOCMODEL_CLANG
 // MRELOCMODEL_CLANG-NOT: -mrelocation-model
 // RUN: %clang --autocomplete=#-mrelocation-mode | FileCheck %s -check-prefix=MRELOCMODEL_CC1
 // MRELOCMODEL_CC1: -mrelocation-model
+// RUN: %clang --autocomplete=-Wma | FileCheck %s -check-prefix=WARNING
+// WARNING: -Wmacro-redefined -Wmain -Wmain-return-type -Wmalformed-warning-check -Wmany-braces-around-scalar-init -Wmax-unsigned-zero
+// RUN: %clang --autocomplete=-Wnoinvalid-pp- | FileCheck %s -check-prefix=NOWARNING
+// NOWARNING: -Wnoinvalid-pp-token