[flang][driver] Add debug options not requiring semantic checks
authorAndrzej Warzynski <andrzej.warzynski@arm.com>
Tue, 30 Mar 2021 10:35:42 +0000 (10:35 +0000)
committerAndrzej Warzynski <andrzej.warzynski@arm.com>
Thu, 8 Apr 2021 09:44:19 +0000 (09:44 +0000)
commite81b3401177a67481605447ea5250d8345cb4341
tree8fd92df50ee929a1f143f426e71c461e3f33db65
parent8675ef100f8cbf59f2e90f4836fb92db83b6062e
[flang][driver] Add debug options not requiring semantic checks

This patch adds two debugging options in the new Flang driver
(flang-new):
  *fdebug-unparse-no-sema
  *fdebug-dump-parse-tree-no-sema
Each of these options combines two options from the "throwaway" driver
(left: f18, right: flang-new):
  * `-fdebug-uparse -fdebug-no-semantics` --> `-fdebug-unparse-no-sema`
  * `-fdebug-dump-parse-tree -fdebug-no-semantics` -->
    `-fdebug-dump-parse-tree-no-sema`

There are no plans to implement `-fdebug-no-semantics` in the new
driver.  Such option would be too powerful. Also, it would only make
sense when combined with specific frontend actions (`-fdebug-unparse`
and `-fdebug-dump-parse-tree`). Instead, this patch adds 2 specialised
options listed above. Each of these is implemented through a dedicated
FrontendAction (also added).

The new frontend actions are implemented in terms of a new abstract base
action: `PrescanAndSemaAction`. This new base class was required so that
we can have finer control over what steps within the frontend are
executed:
  * `PrescanAction`: run the _prescanner_
  * `PrescanAndSemaAction`: run the _prescanner_ and the _parser_ (new
     in this patch)
  * `PrescanAndSemaAction`: run the _prescanner_, _parser_ and run the
    _semantic checks_

This patch introduces `PrescanAndParseAction::BeginSourceFileAction`.
Apart from the semantic checks removed at the end, it is similar to
`PrescanAndSemaAction::BeginSourceFileAction`.

Differential Revision: https://reviews.llvm.org/D99645
clang/include/clang/Driver/Options.td
flang/include/flang/Frontend/FrontendActions.h
flang/include/flang/Frontend/FrontendOptions.h
flang/lib/Frontend/CompilerInvocation.cpp
flang/lib/Frontend/FrontendActions.cpp
flang/lib/FrontendTool/ExecuteCompilerInvocation.cpp
flang/test/Driver/driver-help.f90
flang/test/Driver/dump-parse-tree-no-sema.f90 [new file with mode: 0644]
flang/test/Parser/omp-allocate-unparse.f90
flang/test/Parser/omp-atomic-unparse.f90
flang/tools/f18/f18.cpp