[flang] Merge pull request flang-compiler/f18#331 from flang-compiler/tsk10

Change default for LINK_WITH_FIR to ON.

Original-commit: flang-compiler/f18@ea8944908956f73fb123b6cf4053753b98f28427
Reviewed-on: https://github.com/flang-compiler/f18/pull/331

[flang] Change default for LINK_WITH_FIR to ON.

Original-commit: flang-compiler/f18@b13f99446339666859eb00e896e8d1751423892a
Reviewed-on: https://github.com/flang-compiler/f18/pull/331

[flang] Merge pull request flang-compiler/f18#329 from flang-compiler/tsk10

Add cmake option to link with FIR and LLVM

Original-commit: flang-compiler/f18@ddb43b33ccf52e9083a90d11f00b6a85667617ed
Reviewed-on: https://github.com/flang-compiler/f18/pull/329

[flang] Add cmake option to link with FIR and LLVM

The cmake option -DLINK_WITH_FIR=ON causes the f18 driver to be linked
against FIR and LLVM. When it is set to OFF (the default), the call into
FIR is #ifdef'd out.

The source in lib/FIR is always built; this option only affects linking.

Original-commit: flang-compiler/f18@69569edd4c6abbb7a66c0d8f3595858693a06996
Reviewed-on: https://github.com/flang-compiler/f18/pull/329

[flang] Merge pull request flang-compiler/f18#328 from flang-compiler/eas0

remove unused files and clean up unused warnings

Original-commit: flang-compiler/f18@67ef747557f254d3fb3692bd7eba720a29ad69df
Reviewed-on: https://github.com/flang-compiler/f18/pull/328

[flang] Move virtual dtor to Terminator

Original-commit: flang-compiler/f18@68853d602a6a2c21f4f19b91b58fec1f88473dd6
Reviewed-on: https://github.com/flang-compiler/f18/pull/328

[flang] remove unused files
Cleanup some warnings when building with clang.

Original-commit: flang-compiler/f18@33cf6255d1431a8fa0a30fb4b883615de17bcbb7
Reviewed-on: https://github.com/flang-compiler/f18/pull/328
Tree-same-pre-rewrite: false

[flang] Silence clang warning related to ISO_Fortran_binding.h usage in C++

Original-commit: flang-compiler/f18@85b7f370b4b1e41186bc2cfb7cf55d279085b1d5

[flang] address comments

Original-commit: flang-compiler/f18@7b1fc24265b694ed365879e974810744911f12a2

[flang] remove unused CFI_ISO_FORTRAN_BINDING_FLEXIBLE_ARRAY

Original-commit: flang-compiler/f18@3cf9a625bf6b7c2a62b29074f31a564cc51e5df0
Tree-same-pre-rewrite: false

[flang] Silence clang warning from ISO_Fortran_binding.h usage in C++

Original-commit: flang-compiler/f18@88eb833b14e3f91285605dd4db0e0c021df7fa4c
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#326 from flang-compiler/BUILD_WITH_CLANG_LIBRARIES

Update CMakeList.txt to allow linking with LLVM libc++

Original-commit: flang-compiler/f18@866e188de60e5811882c4c1ea75daa2b448b7b0b
Reviewed-on: https://github.com/flang-compiler/f18/pull/326

[flang] To use LLVM's libc++ instead of GCC's libstdc++, define
BUILD_WITH_CLANG_LIBRARIES on the cmake command line to
be the path to a clang installation with bin, lib, etc.
For this to work, BUILD_WITH_CLANG must be defined too.

Original-commit: flang-compiler/f18@a36d5fee421f2e90293540335c5b887412e31383
Reviewed-on: https://github.com/flang-compiler/f18/pull/326

[flang] Merge pull request flang-compiler/f18#327 from flang-compiler/pmk-nofir

Emergency temporary patch to fix build

Original-commit: flang-compiler/f18@06d71f72a5c97ac7be5cde0150cc6738772ba94a
Reviewed-on: https://github.com/flang-compiler/f18/pull/327

[flang] Temporarily disconnect FIR from f18.cc build

Original-commit: flang-compiler/f18@c610bc2744ad56adae8de09a81069a2c3df396e7
Reviewed-on: https://github.com/flang-compiler/f18/pull/327

[flang] Merge pull request flang-compiler/f18#324 from flang-compiler/eas0

Revisions for review comments.

Original-commit: flang-compiler/f18@5b066774b0c03a45dff94d2ccdf071a7690aabe5
Reviewed-on: https://github.com/flang-compiler/f18/pull/324

[flang] Revisions for review comments.

Original-commit: flang-compiler/f18@1a03f7d5bbf6b0f74a54736a906ea4a1e301f0e9
Reviewed-on: https://github.com/flang-compiler/f18/pull/324

[flang] Merge pull request flang-compiler/f18#323 from flang-compiler/eas0

Fix build breakage

Original-commit: flang-compiler/f18@46e416acc7d318d7681e17f4e10812b4ad6f626b
Reviewed-on: https://github.com/flang-compiler/f18/pull/323

[flang] Fix build breakage

Original-commit: flang-compiler/f18@72d003f89d523f84cfab6ed048897be6bcb7ed92
Reviewed-on: https://github.com/flang-compiler/f18/pull/323

[flang] Merge pull request flang-compiler/f18#319 from flang-compiler/eas0

FIR update

Original-commit: flang-compiler/f18@3f6f710889c68207573ea9eddc962270590a2669
Reviewed-on: https://github.com/flang-compiler/f18/pull/319

[flang] Address review comments; merge with latest breaking changes on master

Original-commit: flang-compiler/f18@ffde96d4866c25c3267332963363d4b6c523325d
Reviewed-on: https://github.com/flang-compiler/f18/pull/319

[flang] Run old clang-format over FIR directory

Original-commit: flang-compiler/f18@0616ac43ecea4b60bb076fb67c2a284cb94835fb
Reviewed-on: https://github.com/flang-compiler/f18/pull/319
Tree-same-pre-rewrite: false

[flang] Repairs for new interfaces

Original-commit: flang-compiler/f18@1a080dfe6a0e87879458cac76fe809eb92437b21
Reviewed-on: https://github.com/flang-compiler/f18/pull/319
Tree-same-pre-rewrite: false

[flang] FIR statements: various reworking of the code to decompose some
operations, get rid of unneeded nodes, restructure DO loops, etc.

Original-commit: flang-compiler/f18@0e0d67fbdae307b63f31ade0a990db8f00fed251
Reviewed-on: https://github.com/flang-compiler/f18/pull/319
Tree-same-pre-rewrite: false

[flang] react to more review comments

Original-commit: flang-compiler/f18@b685d8a588287ac7683fd5626023c0de70fcc69b
Reviewed-on: https://github.com/flang-compiler/f18/pull/319
Tree-same-pre-rewrite: false

[flang] cleanup merge

Original-commit: flang-compiler/f18@ea00eab799cd8e5312d45d8c97bc9a5a3c6a3ba9
Reviewed-on: https://github.com/flang-compiler/f18/pull/319
Tree-same-pre-rewrite: false

[flang] Fixes for building with clang++ and other misc. from review

Original-commit: flang-compiler/f18@c3cdc327863036213dab26abf9e97f23a968c197
Reviewed-on: https://github.com/flang-compiler/f18/pull/319
Tree-same-pre-rewrite: false

[flang] Move over build recipes and rename the library

Original-commit: flang-compiler/f18@51476aa1786de4b98b8189f256ba602298fd4903
Reviewed-on: https://github.com/flang-compiler/f18/pull/319
Tree-same-pre-rewrite: false

[flang] Fortran Intermediate Representation: initial draft based on "CFG" note.

Original-commit: flang-compiler/f18@b7a759539467268c250b239f2e62c854f41ae46e
Reviewed-on: https://github.com/flang-compiler/f18/pull/319
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#322 from flang-compiler/pmk-struct-constr-disambig

Fix two ambiguous parsing cases by patching parse tree in expression semantics

Original-commit: flang-compiler/f18@d4807f136419b075adcaf38b0129ba7e79c994df
Reviewed-on: https://github.com/flang-compiler/f18/pull/322

[flang] Address review comment

Original-commit: flang-compiler/f18@8a9a41487e809e61b173b07f629a8e0251a8b921
Reviewed-on: https://github.com/flang-compiler/f18/pull/322

[flang] Fix misparsings of substrings in the parse tree, not in expressions.

Original-commit: flang-compiler/f18@53d0e26d922d2a7d99599a0f6b7c9a2aa0854007
Reviewed-on: https://github.com/flang-compiler/f18/pull/322
Tree-same-pre-rewrite: false

[flang] add structconst04.f90 test and fixes to pass it

Original-commit: flang-compiler/f18@d857c843f5ef2125e9675eb22f013b225a399a38
Reviewed-on: https://github.com/flang-compiler/f18/pull/322
Tree-same-pre-rewrite: false

[flang] Resolve misparse of structure constructor as function reference.

Original-commit: flang-compiler/f18@5b6b2540f6c66b3f2900b24b06d732de3436b4ea
Reviewed-on: https://github.com/flang-compiler/f18/pull/322
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#321 from flang-compiler/tsk3

Remove build dependency on clang

Original-commit: flang-compiler/f18@737998bb508819772a4f46f10c7d8d9cfaef9070
Reviewed-on: https://github.com/flang-compiler/f18/pull/321

[flang] Remove build dependency on clang

For now all we need to depend on is LLVM.
Use llvm_map_components_to_libnames to find libraries to link against.

Original-commit: flang-compiler/f18@dff1402c2a781b7fff5c691b45e6a7f2e3a6ef61
Reviewed-on: https://github.com/flang-compiler/f18/pull/321

[flang] Merge pull request flang-compiler/f18#320 from flang-compiler/pmk-expr-rearrangement

Rearrange/simplify expr analysis code

Original-commit: flang-compiler/f18@4eaccde5167370eb082ce6ef0247942a230f94f1
Reviewed-on: https://github.com/flang-compiler/f18/pull/320

[flang] Rearrange/simplify expr analysis code

Original-commit: flang-compiler/f18@aa9f3a7cca821bf8ea430c10fcae49b295ccd489
Reviewed-on: https://github.com/flang-compiler/f18/pull/320

[flang] Merge pull request flang-compiler/f18#317 from flang-compiler/tsk10

Simplify Semantics::Perform

Original-commit: flang-compiler/f18@c435fe65a4c027300365dce9a54240705db1a945
Reviewed-on: https://github.com/flang-compiler/f18/pull/317

[flang] Simplify Semantics::Perform

`Semantics::Perform` is mostly a series of calls followed by a check
for fatal errors. There is more error checking logic than real code.

To make it clearer, change each of the phases it calls to return true
on success so that `Perform` can just call them one after the other.

Original-commit: flang-compiler/f18@a218cac788fdc4018645651964e75221c6f31653
Reviewed-on: https://github.com/flang-compiler/f18/pull/317

[flang] Merge pull request flang-compiler/f18#316 from flang-compiler/pmk-expr-walk

Add Expression traversal framework, use it to reimplement IsConstantE…

Original-commit: flang-compiler/f18@90cd33adcb6c420d0791a094c456832e4d78d548
Reviewed-on: https://github.com/flang-compiler/f18/pull/316

[flang] add descender.h

Original-commit: flang-compiler/f18@cfc3082b7ae840168e891dcf25e0034a4193a3fd
Reviewed-on: https://github.com/flang-compiler/f18/pull/316

[flang] add rewriting as well as const visitation

Original-commit: flang-compiler/f18@1224eaee85c65d70724385d222ba72541dd80213
Reviewed-on: https://github.com/flang-compiler/f18/pull/316
Tree-same-pre-rewrite: false

[flang] More rearrangement

Original-commit: flang-compiler/f18@7a675d9df6ac161d68314459b3a54575eda1d354
Reviewed-on: https://github.com/flang-compiler/f18/pull/316
Tree-same-pre-rewrite: false

[flang] Hide implementation better

Original-commit: flang-compiler/f18@2118b463140f027c81659c647639a03a820437ad
Reviewed-on: https://github.com/flang-compiler/f18/pull/316
Tree-same-pre-rewrite: false

[flang] back out one change

Original-commit: flang-compiler/f18@27fb43b6ed1a4874c153ffc1219dcbdca931804e
Reviewed-on: https://github.com/flang-compiler/f18/pull/316
Tree-same-pre-rewrite: false

[flang] Address review comments

Original-commit: flang-compiler/f18@3ed6199fedc2ba0d527cc7dd46c5ab67a7f0f1c7
Reviewed-on: https://github.com/flang-compiler/f18/pull/316
Tree-same-pre-rewrite: false

[flang] Improve detection of default Handle() callback

Original-commit: flang-compiler/f18@c09c4c9e00d15a5dd391216662665d48a908c4fd
Reviewed-on: https://github.com/flang-compiler/f18/pull/316
Tree-same-pre-rewrite: false

[flang] some tweaks

Original-commit: flang-compiler/f18@07d196386e139b65fe18d4df32f06f994627aac3
Reviewed-on: https://github.com/flang-compiler/f18/pull/316
Tree-same-pre-rewrite: false

[flang] Add Expression traversal framework, use it to reimplement IsConstantExpr()

Original-commit: flang-compiler/f18@f5d39159354a994cdeb5ab1d4cbfea188c14e681
Reviewed-on: https://github.com/flang-compiler/f18/pull/316
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#315 from flang-compiler/tsk10

Create framework for checking statement semantics

Original-commit: flang-compiler/f18@0fcdb68061b8d008d22e0cc0ff4ccdbb40ab8f44
Reviewed-on: https://github.com/flang-compiler/f18/pull/315

[flang] Move ExprChecker into separate pass

DoConcurrentChecker depends on expressions being fully resolved so it
can't be in the same pass as ExprChecker. The same will probably
apply to AssignmentChecker when its finished.

Checks that don't depend on expressions can go in the first pass
with ExprChecker.

Original-commit: flang-compiler/f18@c0785ec06f58098d262cf2f791a98e74bdcef11b
Reviewed-on: https://github.com/flang-compiler/f18/pull/315

[flang] Add test for AssignmentChecker

Add a test to verify that AssignmentChecker is actually running.

Original-commit: flang-compiler/f18@2c91604e9bff06eb8d63d79abda916802966602f
Reviewed-on: https://github.com/flang-compiler/f18/pull/315
Tree-same-pre-rewrite: false

[flang] Create framework for checking statement semantics

Add `SemanticsVisitor` as the visitor class to perform statement
semantics checks. Its template parameters are "checker" classes
that perform the checks. They have `Enter` and `Leave` functions
that are called for the corresponding parse tree nodes (`Enter`
before the children, `Leave` after). Unlike `Pre` and `Post` in
visitors they cannot prevent the parse tree walker from visiting
child nodes.

Existing checks have been incorporated into this framework:
- `ExprChecker` replaces `AnalyzeExpressions()`
- `AssignmentChecker` replaces `AnalyzeAssignments()`
- `DoConcurrentChecker` replaces `CheckDoConcurrentConstraints()`

Adding a new checker requires:
- defining the checker class:
  - with BaseChecker as virtual base class
  - constructible from `SemanticsContext`
  - with Enter/Leave functions for nodes of interest
- add the checker class to the template parameters of `StatementSemantics`

Because these checkers and also `ResolveNamesVisitor` require tracking
the current statement source location, that has been moved into
`SemanticsContext`. `ResolveNamesVisitor` and `SemanticsVisitor`
update the location when `Statement` nodes are encountered, making it
available for error messages.

`AnalyzeKindSelector()` now has access to the current statement through
the context and so no longer needs to have it passed in.

Test `assign01.f90` was added to verify that `AssignmentChecker` is
actually doing something.

Original-commit: flang-compiler/f18@3a222c36731029fabf026e5301dc60f0587595be
Reviewed-on: https://github.com/flang-compiler/f18/pull/315
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#311 from flang-compiler/pmk-struct-checks

More structure constructor semantics checking

Original-commit: flang-compiler/f18@5561c9012c07c21cd043b0b0b8b2a03d6e42bebe
Reviewed-on: https://github.com/flang-compiler/f18/pull/311

[flang] Tweak API per review

Original-commit: flang-compiler/f18@c0ab787cd1eb82a13fca9a473973b25e737da77a
Reviewed-on: https://github.com/flang-compiler/f18/pull/311

[flang] Use value()/has_value() on Indirection class templates instead of operator*/operator->

Original-commit: flang-compiler/f18@a97f377ae6051d877df82036983cc6209a2e0d95
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] Dodge bogus G++ 8.1.0 build warning

Original-commit: flang-compiler/f18@582c6d1eca5bc29fddadae4d25e418da4ace2c11
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] Improve error messages

Original-commit: flang-compiler/f18@40461345124b95de1f35828885e95d8bf0a235f1
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] Add lib/semantics/tools.{h,cc}

Original-commit: flang-compiler/f18@c9823da20746313005ee017413f8207a720a10b0
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] C1594 constraint checking on pointer components in struct constructors

Original-commit: flang-compiler/f18@386cd8a9b43f4e65c3e42febbae991fa87d277a9
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] Length conversions in array constructors, and fix their formatting

Original-commit: flang-compiler/f18@88cdb49f4892a20f2628f11373a0f1c9c32a6c1e
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] Character length conversion on structure constructor component assignments

Original-commit: flang-compiler/f18@051c1dd923a3b321d1a19768414caf93732a3426
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] Add SetLength operator to make character length changes explicit

Original-commit: flang-compiler/f18@f2d751d8a6c1bf31f69031bbdab0a823999ebf5c
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] snapshot of work in progress

Original-commit: flang-compiler/f18@56e83d4dd64dd7d30b2ce4bbf124f2c39bc14b58
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] Represent NULL()

Original-commit: flang-compiler/f18@2c3368fb5f6178bb997936bb506deecc2d8b7d03
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] Type checking on values in structure components

Original-commit: flang-compiler/f18@bea98aeb9638b9d584488ae5faf72d53f1747a5f
Reviewed-on: https://github.com/flang-compiler/f18/pull/311
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#314 from flang-compiler/pmk-indirection

Add `ForwardReference<>` class template

Original-commit: flang-compiler/f18@b541a4d167530138025b8a0c8dd1031144ab8435
Reviewed-on: https://github.com/flang-compiler/f18/pull/314

[flang] Add ForwardReference<> + documentation + clean-up

Original-commit: flang-compiler/f18@09e9501951499625fdabdc04f3bcf7ae85b37467
Reviewed-on: https://github.com/flang-compiler/f18/pull/314

[flang] checkpoint

Original-commit: flang-compiler/f18@65abebd838ef6b20960f69595709db55f3e5a9b7
Reviewed-on: https://github.com/flang-compiler/f18/pull/314
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#313 from flang-compiler/pmk-fix312

Fix flang-compiler/f18#312

Original-commit: flang-compiler/f18@74a9426adf29b21a0971f6db224efbd77da989af
Reviewed-on: https://github.com/flang-compiler/f18/pull/313

[flang] Fix a typo in documentation

Original-commit: flang-compiler/f18@3248ec1cf93a18a7172eaeb90688de9fae4ab753
Reviewed-on: https://github.com/flang-compiler/f18/pull/313

[flang] Fix accidentally modified comment

Original-commit: flang-compiler/f18@7d0b365a6dcd02df245ee6ea2fcbadbdb31e86f6
Reviewed-on: https://github.com/flang-compiler/f18/pull/313
Tree-same-pre-rewrite: false

[flang] check out with all versions

Original-commit: flang-compiler/f18@0b1369ce5511d728c10c1b00ca14a2c9c4572ac7
Reviewed-on: https://github.com/flang-compiler/f18/pull/313
Tree-same-pre-rewrite: false

[flang] Fix flang-compiler/f18#312

Original-commit: flang-compiler/f18@625ffb4f1a09343725907fe51597e88e28a0ca91
Reviewed-on: https://github.com/flang-compiler/f18/pull/313
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#310 from flang-compiler/psteinfeld

Fixed reference to a header file

Original-commit: flang-compiler/f18@658bc758d7c4bcea7ffbf06968a2faa3f4c8a124
Reviewed-on: https://github.com/flang-compiler/f18/pull/310

[flang] Fixed reference to a header file

Original-commit: flang-compiler/f18@22f93f0b307384ebe022aa300771fef40039c11e
Reviewed-on: https://github.com/flang-compiler/f18/pull/310

[flang] Merge pull request flang-compiler/f18#308 from flang-compiler/pmk-cleanups

Rename to Fortran.h, update style guide, run clang-format on everything

Original-commit: flang-compiler/f18@0cf07c3ace6b713f8ec0fb348af99a4ef04dd9e3
Reviewed-on: https://github.com/flang-compiler/f18/pull/308

[flang] Missed a fortran.h instance

Original-commit: flang-compiler/f18@3a9a185383fb4bf967624258f59e2f22cd143ed5
Reviewed-on: https://github.com/flang-compiler/f18/pull/308

[flang] Rename to Fortran.h, update style guide, run clang-format

Original-commit: flang-compiler/f18@aa2907d2260c34085360917e7fab43d8ee79b6e4
Reviewed-on: https://github.com/flang-compiler/f18/pull/308
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#309 from flang-compiler/tsk2c

Fix bug in test_modfile.sh

Original-commit: flang-compiler/f18@6e95724f0e2efda36c0efc16d7f6bfde90975a00
Reviewed-on: https://github.com/flang-compiler/f18/pull/309

[flang] Fix bug in test_modfile.sh

The expected mod files specified in the test do not necessarily
appear in sorted order, and the desired order depends on what the
`comm` command expects. So sort them to be sure it is right.

Original-commit: flang-compiler/f18@730d0d0562dd0a4eabfde020fef9fe371d401ff5
Reviewed-on: https://github.com/flang-compiler/f18/pull/309

[flang] Merge pull request flang-compiler/f18#305 from flang-compiler/tsk2

Various name resolution bug fixes

Original-commit: flang-compiler/f18@fc831f600e5d37f646d4a83fbec7befc4d5dffda
Reviewed-on: https://github.com/flang-compiler/f18/pull/305

[flang] Fix bug handling function prefix type

This showed up in procinterface01. A function can have more than one
PrefixSpec (e.g. `real elemental f()`). We need to ignore that ones
that aren't types.

Also, process the type after the ImplicitPart rather than after the
SpecificationPart. The type of the function result variable could
be accessed between those places.

Original-commit: flang-compiler/f18@df85eedb925b6f8739d6f6ccd9820ff5d9e4f4c5
Reviewed-on: https://github.com/flang-compiler/f18/pull/305

[flang] Fix bug with host-association in module procedure interface body

A module procedure interface body can access entities in its host
without an IMPORT statement. So the `ImportKind` of the scope created
for such an interface body should be `Default`, not `None` as it is
for other interface bodies.

Original-commit: flang-compiler/f18@24bb2668fdb626a4df76719345b02e533d015d79
Reviewed-on: https://github.com/flang-compiler/f18/pull/305
Tree-same-pre-rewrite: false

[flang] Allow module procedure and generic with same name

The `GenericDetails::CheckSpecific()` check was happening too early.
We have to wait until all procedures of the generic have been seen.
The generic can have the same name as a module procedure only if that
module procedure is a specific procedure of the generic.

Improve the `SayAlreadyDeclared` error message when the previous
declaration is a use-association

Original-commit: flang-compiler/f18@269e3db6020a5acc51a291dfea98455e6a97d2d5
Reviewed-on: https://github.com/flang-compiler/f18/pull/305
Tree-same-pre-rewrite: false

[flang] Fix .mod file for symbols with same name as generic

When a generic has the same name as a module procedure or derived type,
the latter weren't being written to the `.mod` file. Fix that by calling
`PutSymbol()` on those symbols from the generic. Change `PutSymbol()` to
accept `Symbol *` to make that more convenient.

Original-commit: flang-compiler/f18@1778efe981812b1d1d1b684647c72085f44c3209
Reviewed-on: https://github.com/flang-compiler/f18/pull/305
Tree-same-pre-rewrite: false

[flang] Fix resolution of function prefix type

When a function-stmt has a type in the prefix (`type(t) function f()`),
the type cannot be resolve until after processing the USE and IMPLICIT
statements. So save the parse-tree of the type and process it at the
end of the specification section.

Add `ProcessTypeSpec()` to handle the process of setting up to walk
a type spec, walking it, restoring the state, and returning the type
spec. We do this several other places too.

Original-commit: flang-compiler/f18@bcde294d0e62c6ef8506392f66816814ae976dff
Reviewed-on: https://github.com/flang-compiler/f18/pull/305
Tree-same-pre-rewrite: false

[flang] Fix bug determining type of statement entity

A statement entity (`data-i-do-variable` or `ac-do-variable`) that
doesn't have a type specified gets the type it would have in the
enclosing scope. That means if there is a visible variable with the
same name, the statement entity gets its type. We were failing to
do that and just applying the implicit rules.

Original-commit: flang-compiler/f18@72bc7c29ba8d4be6a7c93080bb7fac7a3bc73577
Reviewed-on: https://github.com/flang-compiler/f18/pull/305
Tree-same-pre-rewrite: false

[flang] Handle subprogram declaration after call

If an external subprogram is called and then declared, we have to
replace the `ProcEntityDetails` with `SubprogramDetails` in the symbol.
While doing so we can also check that the call was consistent with the
declaration for function vs. subprogram.

Original-commit: flang-compiler/f18@e43a2dae790cd0f54ecaec2ffc1235fd2b7754e9
Reviewed-on: https://github.com/flang-compiler/f18/pull/305
Tree-same-pre-rewrite: false

[flang] Fix bug determining function vs. subroutine

We were setting `expectedProcFlag_` to indicate if a `ProcedureDesignator`
was used in a function or subroutine context. That didn't work if they
were nested, for example: `call f(g())`.

Instead, at the point we know function vs. subroutine (i.e. in the
`CallStmt` and `FunctionReference` nodes), explicitly walk the children,
passing in the flag.

Original-commit: flang-compiler/f18@8a13283f98c366b74b35bc003f7bc908212a0c6c
Reviewed-on: https://github.com/flang-compiler/f18/pull/305
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#307 from flang-compiler/pmk-fixes

fix flang-compiler/f18#303, better error recovery for misplaced type parameter declarat…

Original-commit: flang-compiler/f18@79684ed2ebd3d1a3670fad87de69f104305116cc
Reviewed-on: https://github.com/flang-compiler/f18/pull/307

[flang] fix flang-compiler/f18#303, better error recovery for misplaced type parameter declarations

Original-commit: flang-compiler/f18@ebaa23cbcd91ba83b65b8dd174baffab1395bc65
Reviewed-on: https://github.com/flang-compiler/f18/pull/307

[flang] Merge pull request flang-compiler/f18#306 from flang-compiler/pmk-documentation

Small edits to C++17 usage notes

Original-commit: flang-compiler/f18@0e51862dd2646ee763d8f31628ba61f0621072ea
Reviewed-on: https://github.com/flang-compiler/f18/pull/306

[flang] Small edits to C++17 usage notes

Original-commit: flang-compiler/f18@bdf62ac90020c84516400085b75109979d599dd7
Reviewed-on: https://github.com/flang-compiler/f18/pull/306

[flang] Merge pull request flang-compiler/f18#294 from flang-compiler/ir2

Fortran IR: part 2, lowest layer of the IR hierarchy. Specifically, Basic Blocks

Original-commit: flang-compiler/f18@5bae9491740cf402218233fd1bc69ee9c92d8a8b
Reviewed-on: https://github.com/flang-compiler/f18/pull/294

[flang] address review comments

Original-commit: flang-compiler/f18@b1c731b0266576d103f2dc44dfdb3410795cd81d
Reviewed-on: https://github.com/flang-compiler/f18/pull/294

[flang] respond to review comments - part 2

Original-commit: flang-compiler/f18@5e4ed6a3128eb32cf93558c97ce116f7f18e4b92
Reviewed-on: https://github.com/flang-compiler/f18/pull/294
Tree-same-pre-rewrite: false

[flang] Fortran IR: lowest layer of the IR hierarchy. Specifically, Basic Blocks
contain Statements.  This layer is still evolving as the IR takes better
shape and other code in the compiler is written.

Original-commit: flang-compiler/f18@e1a282296b4dc90d05acb7d67f536f169fa36a39
Reviewed-on: https://github.com/flang-compiler/f18/pull/294
Tree-same-pre-rewrite: false

[flang] Merge pull request flang-compiler/f18#293 from flang-compiler/ir1

Fortran IR: part 1. staged pull request for the "upper layers" of the IR.  The

Original-commit: flang-compiler/f18@f978be5b8ed77bd3ce62ca1b5c99d3bd42863b82
Reviewed-on: https://github.com/flang-compiler/f18/pull/293