[flang][driver] Add support for `-mmlir`
The semantics of `-mmlir` are identical to `-mllvm`. The only notable
difference is that `-mmlir` options should be forwarded to MLIR rather
than LLVM.
Note that MLIR llvm::cl options are lazily constructed on demand (see
the definition of options in PassManagerOptions.cpp). This means that:
* MLIR global options are only visible when explicitly initialised and
displayed only when using `-mmlir --help`,
* Flang and LLVM global options are always visible and displayed when
using either `-mllvm -help` or `-mmlir --help`.
In other words, `-mmlir --help` is a superset of `-mllvm --help`. This is not
ideal, but we'd need to refactor all option definitions in Flang and
LLVM to improve this. I suggesting leaving this for later.
Differential Revision: https://reviews.llvm.org/D123297
diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp
index 283b5ca..63e3c08 100644
--- a/clang/lib/Driver/ToolChains/Flang.cpp
+++ b/clang/lib/Driver/ToolChains/Flang.cpp
@@ -113,6 +113,11 @@
A->render(Args, CmdArgs);
}
+ for (const Arg *A : Args.filtered(options::OPT_mmlir)) {
+ A->claim();
+ A->render(Args, CmdArgs);
+ }
+
if (Output.isFilename()) {
CmdArgs.push_back("-o");
CmdArgs.push_back(Output.getFilename());
