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
This patch adds support for generating MLIR files in Flang's frontend
driver (i.e. `flang-new -fc1`). `-emit-fir` is added as an alias for
`-emit-mlir`. We may want to decide to split the two in the future.
A new parent class for code-gen frontend actions is introduced:
`CodeGenAction`. We will be using this class to encapsulate logic shared
between all code-generation actions, but not required otherwise. For
now, it will:
* run prescanning, parsing and semantic checks,
* lower the input to MLIR.
`EmitObjAction` is updated to inherit from this class. This means that
the behaviour of `flang-new -fc1 -emit-obj` is also updated (previously,
it would just exit immediately). This change required
`flang/test/Driver/syntax-only.f90` to be updated.
For `-emit-fir`, a specialisation of `CodeGenAction` is introduced:
`EmitMLIRAction`. The key logic for this class is implemented in
`EmitMLIRAction::ExecuteAction`.
Differential Revision: https://reviews.llvm.org/D118985
This patch introduces the dependencies required to read and manage input files
provided by the command line option. It also adds the infrastructure to create
and write to output files. The output is sent to either stdout or a file
(specified with the `-o` flag).
Separately, in order to be able to test the code for file I/O, it adds
infrastructure to create frontend actions. As a basic testable example, it adds
the `InputOutputTest` FrontendAction. The sole purpose of this action is to
read a file from the command line and print it either to stdout or the output
file. This action is run by using the `-test-io` flag also introduced in this
patch (available for `flang-new` and `flang-new -fc1`). With this patch:
```
flang-new -test-io input-file.f90
```
will read input-file.f90 and print it in the output file.
The `InputOutputTest` frontend action has been introduced primarily to
facilitate testing. It is hidden from users (i.e. it's only displayed with
`--help-hidden`). Currently Clang doesn’t have an equivalent action.
`-test-io` is used to trigger the InputOutputTest action in the Flang frontend
driver. This patch makes sure that “flang-new” forwards it to “flang-new -fc1"
by creating a preprocessor job. However, in Flang.cpp, `-test-io` is passed to
“flang-new -fc1” without `-E`. This way we make sure that the preprocessor is
_not_ run in the frontend driver. This is the desired behaviour: `-test-io`
should only read the input file and print it to the output stream.
co-authored-by: Andrzej Warzynski <andrzej.warzynski@arm.com>
Differential Revision: https://reviews.llvm.org/D87989
The Flang driver depends on libclangBasic. This means, among other
things, that some of the tablegen files (e.g. diagnostic definitions)
need to be generated before various libclangBasic header files can be
included (e.g. DiagnosticIDs.h). If we are lucky, libclangBasic is
indeed built before various flang driver libraries that depend on it
are. This patch makes sure that this is deterministic - i.e.
libclangBasic is built before the Flang driver libraries are.
Differential Revision: https://reviews.llvm.org/D88110
Summary:
This is the first patch implementing the new Flang driver as outlined in [1],
[2] & [3]. It creates Flang driver (`flang-new`) and Flang frontend driver
(`flang-new -fc1`). These will be renamed as `flang` and `flang -fc1` once the
current Flang throwaway driver, `flang`, can be replaced with `flang-new`.
Currently only 2 options are supported: `-help` and `--version`.
`flang-new` is implemented in terms of libclangDriver, defaulting the driver
mode to `FlangMode` (added to libclangDriver in [4]). This ensures that the
driver runs in Flang mode regardless of the name of the binary inferred from
argv[0].
The design of the new Flang compiler and frontend drivers is inspired by it
counterparts in Clang [3]. Currently, the new Flang compiler and frontend
drivers re-use Clang libraries: clangBasic, clangDriver and clangFrontend.
To identify Flang options, this patch adds FlangOption/FC1Option enums.
Driver::printHelp is updated so that `flang-new` prints only Flang options.
The new Flang driver is disabled by default. To enable it, set
`-DBUILD_FLANG_NEW_DRIVER=ON` when configuring CMake and add clang to
`LLVM_ENABLE_PROJECTS` (e.g. -DLLVM_ENABLE_PROJECTS=“clang;flang;mlir”).
[1] “RFC: new Flang driver - next steps”
http://lists.llvm.org/pipermail/flang-dev/2020-July/000470.html
[2] “RFC: Adding a fortran mode to the clang driver for flang”
http://lists.llvm.org/pipermail/cfe-dev/2019-June/062669.html
[3] “RFC: refactoring libclangDriver/libclangFrontend to share with Flang”
http://lists.llvm.org/pipermail/cfe-dev/2020-July/066393.html
[4] https://reviews.llvm.org/rG6bf55804924d5a1d902925ad080b1a2b57c5c75c
co-authored-by: Andrzej Warzynski <andrzej.warzynski@arm.com>
Reviewed By: richard.barton.arm, sameeranjoshi
Differential Revision: https://reviews.llvm.org/D86089
Andrzej Warzynski