[flang] Adding support of -fcoarray flang and init PRIF (#151675)

In relation to the approval and merge of the
[PRIF](https://github.com/llvm/llvm-project/pull/76088) specification
about multi-image features in Flang, here is a first PR to add support
for the `-fcoarray` compilation flag and the initialization of the PRIF
environment.
Other PRs will follow for adding support of lowering to PRIF.

1 files changed, 11 insertions, 0 deletions

diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index 3811a87..265ba8e 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -1152,6 +1152,17 @@ static bool parseDialectArgs(CompilerInvocation &res, llvm::opt::ArgList &args,
       diags.Report(diagID);
     }
   }
+  // -fcoarray
+  if (args.hasArg(clang::driver::options::OPT_fcoarray)) {
+    res.getFrontendOpts().features.Enable(
+        Fortran::common::LanguageFeature::Coarray);
+    const unsigned diagID =
+        diags.getCustomDiagID(clang::DiagnosticsEngine::Warning,
+                              "Support for multi image Fortran features is "
+                              "still experimental and in development.");
+    diags.Report(diagID);
+  }
+
   return diags.getNumErrors() == numErrorsBefore;
 }