[clang] NFC: Extract DiagnosticOptions parsing

The way we parse `DiagnosticOptions` is a bit involved.

`DiagnosticOptions` are parsed as part of the cc1-parsing function `CompilerInvocation::CreateFromArgs` which takes `DiagnosticsEngine` as an argument to be able to report errors in command-line arguments. But to create `DiagnosticsEngine`, `DiagnosticOptions` are needed. This is solved by exposing the `ParseDiagnosticArgs` to clients and making its `DiagnosticsEngine` argument optional, essentially breaking the dependency cycle.

The `ParseDiagnosticArgs` function takes `llvm::opt::ArgList &`, which each client needs to create from the command-line (typically represented as `std::vector<const char *>`). Creating this data structure in this context is somewhat particular. This code pattern is copy-pasted in some places across the upstream code base and also in downstream repos. To make things a bit more uniform, this patch extracts the code into a new reusable function: `CreateAndPopulateDiagOpts`.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D108918

1 files changed, 2 insertions, 7 deletions

diff --git a/clang/lib/Interpreter/Interpreter.cpp b/clang/lib/Interpreter/Interpreter.cpp
index 937504f..3e8d388 100644
--- a/clang/lib/Interpreter/Interpreter.cpp
+++ b/clang/lib/Interpreter/Interpreter.cpp
@@ -147,15 +147,10 @@ IncrementalCompilerBuilder::create(std::vector<const char *> &ClangArgv) {
   // Buffer diagnostics from argument parsing so that we can output them using a
   // well formed diagnostic object.
   IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
-  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
+  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts =
+      CreateAndPopulateDiagOpts(ClangArgv);
   TextDiagnosticBuffer *DiagsBuffer = new TextDiagnosticBuffer;
   DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagsBuffer);
-  unsigned MissingArgIndex, MissingArgCount;
-  const llvm::opt::OptTable &Opts = driver::getDriverOptTable();
-  llvm::opt::InputArgList ParsedArgs =
-      Opts.ParseArgs(ArrayRef<const char *>(ClangArgv).slice(1),
-                     MissingArgIndex, MissingArgCount);
-  ParseDiagnosticArgs(*DiagOpts, ParsedArgs, &Diags);
 
   driver::Driver Driver(/*MainBinaryName=*/ClangArgv[0],
                         llvm::sys::getProcessTriple(), Diags);