[Flang][OpenMP][Driver][MLIR] Port fopenmp-host-ir-file-path flag and add MLIR module attribute to proliferate to OpenMP IR lowering

This patch ports the fopenmp-host-ir-file-path flag from Clang to Flang-new, this flag
is added by the driver to the device pass when doing two phase compilation (device + host).

This flag is then applied to the module when compiling during the OpenMP device phase.
This file can then be utilised during lowering of the OpenMP dialect to LLVM-IR, which
allows the device and host to maintain 1:1 mapping of OpenMP metadata for variables
during lowering via the OpenMPIRBuilders loadOffloadInfoMetadata facilities
(which is used for declare target and I believe target regions as well).

Reviewer: awarzynski

Differential Revision: https://reviews.llvm.org/D148038

1 files changed, 10 insertions, 0 deletions

diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
index c6d5152..6672777 100644
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -726,6 +726,16 @@ static bool parseDialectArgs(CompilerInvocation &res, llvm::opt::ArgList &args,
     if (args.hasArg(clang::driver::options::OPT_fopenmp_is_device)) {
       res.getLangOpts().OpenMPIsDevice = 1;
 
+      // Get OpenMP host file path if any and report if a non existent file is
+      // found
+      if (auto *arg = args.getLastArg(
+              clang::driver::options::OPT_fopenmp_host_ir_file_path)) {
+        res.getLangOpts().OMPHostIRFile = arg->getValue();
+        if (!llvm::sys::fs::exists(res.getLangOpts().OMPHostIRFile))
+          diags.Report(clang::diag::err_drv_omp_host_ir_file_not_found)
+              << res.getLangOpts().OMPHostIRFile;
+      }
+
       if (args.hasFlag(
               clang::driver::options::OPT_fopenmp_assume_teams_oversubscription,
               clang::driver::options::