[flang] Check assignment conformance for derived types (#99059)

Derived type assignment checking needs to account for the possibility of
derived assignment. The implementation was checking compile-

[flang] Check assignment conformance for derived types (#99059)

Derived type assignment checking needs to account for the possibility of
derived assignment. The implementation was checking compile-time
conformance errors only on the path for assignments of intrinsic types.
Add a static array conformance check in the derived type flow once it
has been established that no defined assignment exists.

Fixes https://github.com/llvm/llvm-project/issues/98981.

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[flang] Enforce F'2023 C7125

An item whose declared type is ABSTRACT may not appear in an
array constructor.

Differential Revision: https://reviews.llvm.org/D155969

[flang] Compile-time checks for shape conformance on assignments

Assignment statements need to check for array shape conformance
errors that are discernable at compilation time.

Differential Revisi

[flang] Compile-time checks for shape conformance on assignments

Assignment statements need to check for array shape conformance
errors that are discernable at compilation time.

Differential Revision: https://reviews.llvm.org/D132161

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[flang] Fold TRANSFER()

Fold usage of the raw data reinterpretation intrinsic function TRANSFER().

Differential Revision: https://reviews.llvm.org/D129671

[Flang] Ported test_errors.sh to Python

To enable Flang testing on Windows, shell scripts have to be ported to Python. In this patch the "test_errors.sh" script is ported to python ("test_errors.py"

[Flang] Ported test_errors.sh to Python

To enable Flang testing on Windows, shell scripts have to be ported to Python. In this patch the "test_errors.sh" script is ported to python ("test_errors.py"). The RUN line of existing tests was changed to make use of the python script.

Used python regex in place of awk/sed.

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D107575

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[flang] Extension: reduced scope for some implied DO loop indices

The index of an implied DO loop in a DATA statement or array
constructor is defined by Fortran 2018 to have scope over its
implied D

[flang] Extension: reduced scope for some implied DO loop indices

The index of an implied DO loop in a DATA statement or array
constructor is defined by Fortran 2018 to have scope over its
implied DO loop. This definition is unfortunate, because it
requires the implied DO loop's bounds expressions to be in the
scope of the index variable. Consequently, in code like

integer, parameter :: j = 5
real, save :: a(5) = [(j, j=1, j)]

the upper bound of the loop is a reference to the index variable,
not the parameter in the enclosing scope.

This patch limits the scope of the index variable to the "body"
of the implied DO loop as one would naturally expect, with a warning.
I would have preferred to make this a hard error, but most Fortran
compilers treat this case as f18 now does. If the standard
were to be fixed, the warning could be made optional.

Differential Revision: https://reviews.llvm.org/D108595

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[flang] Cope with errors with array constructors

When a program attempts to put something like a subprogram
into an array constructor, emit an error rather than crashing.

Differential Revision: htt

[flang] Cope with errors with array constructors

When a program attempts to put something like a subprogram
into an array constructor, emit an error rather than crashing.

Differential Revision: https://reviews.llvm.org/D104336

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[flang][windows] Run regression tests under Windows. NFCI.

Allow the lit test suite to run under Windows. This encompasses the following changes:

* Define `lit_tools_dir` for flang's test configur

[flang][windows] Run regression tests under Windows. NFCI.

Allow the lit test suite to run under Windows. This encompasses the following changes:

* Define `lit_tools_dir` for flang's test configuration
* Replace `(<command> || true)` idiom with `not <command>`
* Add `REQUIRES: shell` on tests that invoke a shell script

Reviewed By: awarzynski

Differential Revision: https://reviews.llvm.org/D89368

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[flang] Support known constant lengths in DynamicType

The constexpr-capable class evaluate::DynamicType represented
CHARACTER length only with a nullable pointer into the declared
parameters of type

[flang] Support known constant lengths in DynamicType

The constexpr-capable class evaluate::DynamicType represented
CHARACTER length only with a nullable pointer into the declared
parameters of types in the symbol table, which works fine for
anything with a declaration but turns out to not suffice to
describe the results of the ACHAR() and CHAR() intrinsic
functions. So extend DynamicType to also accommodate known
constant CHARACTER lengths, too; use them for ACHAR & CHAR;
clean up several use sites and fix regressions found in test.

Differential Revision: https://reviews.llvm.org/D103571

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[flang] Update the regression tests to use the new driver when enabled

This patch updates most of the remaining regression tests (~400) to use
`flang-new` rather then `f18` when `FLANG_BUILD_NEW_DRI

[flang] Update the regression tests to use the new driver when enabled

This patch updates most of the remaining regression tests (~400) to use
`flang-new` rather then `f18` when `FLANG_BUILD_NEW_DRIVER` is set.
This allows us to share more Flang regression tests between `f18` and
`flang-new`. A handful of tests have not been ported yet - these are
currently either failing or not supported by the new driver.

Summary of changes:
* RUN lines in tests are updated to use `%flang_fc1` instead of `%f18`
* option spellings in tests are updated to forms accepted by both `f18` and
`flang-new`
* variables in Bash scripts are renamed (e.g. F18 --> FLANG_FC1)
The updated tests will now be run with the new driver, `flang-new`,
whenever it is enabled (i.e when `FLANG_BUILD_NEW_DRIVER` is set).

Although this patch touches many files, vast majority of the changes are
automatic:
```
grep -IEZlr "%f18" flang/test/ | xargs -0 -l sed -i 's/%f18/%flang_fc1/g
```

Differential Revision: https://reviews.llvm.org/D100309

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[flang] Fix problems with constant arrays with lower bounds that are not 1

There were two problems with constant arrays whose lower bound is not 1.
First, when folding the arrays, we were creating t

[flang] Fix problems with constant arrays with lower bounds that are not 1

There were two problems with constant arrays whose lower bound is not 1.
First, when folding the arrays, we were creating the folded array to have lower
bounds of 1 but, we were not re-adjusting their lower bounds to the
declared values. Second, we were not calculating the extents correctly.
Both of these problems led to bogus error messages.

I fixed the first problem by adjusting the lower bounds in
NonPointerInitializationExpr() in Evaluate/check-expression.cpp. I wrote the
class ArrayConstantBoundChanger, which is similar to the existing class
ScalarConstantExpander. In the process of implementing and testing it, I found
a bug that I fixed in ScalarConstantExpander which caused it to infinitely
recurse on parenthesized expressions. I also removed the unrelated class
ScalarExpansionVisitor, which was not used.

I fixed the second problem by changing the formula that calculates upper bounds
in in the function ComputeUpperBound() in Evaluate/shape.cpp.

I added tests that trigger the bogus error messages mentioned above along with
a constant folding tests that uses array operands with shapes that conform but
have different bounds.

In the process of adding tests, I discovered that tests in
Evaluate/folding09.f90 and folding16.f90 were written incorrectly, and I
fixed them. This also revealed a bug in contant folding of the
intrinsic "lbounds" which I plan to fix in a later change.

Differential Revision: https://reviews.llvm.org/D95449

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[flang] Improve initializer semantics, esp. for component default values

This patch plugs many holes in static initializer semantics, improves error
messages for default initial values and other com

[flang] Improve initializer semantics, esp. for component default values

This patch plugs many holes in static initializer semantics, improves error
messages for default initial values and other component properties in
parameterized derived type instantiations, and cleans up several small
issues noticed during development. We now do proper scalar expansion,
folding, and type, rank, and shape conformance checking for component
default initializers in derived types and PDT instantiations.
The initial values of named constants are now guaranteed to have been folded
when installed in the symbol table, and are no longer folded or
scalar-expanded at each use in expression folding. Semantics documentation
was extended with information about the various kinds of initializations
in Fortran and when each of them are processed in the compiler.

Some necessary concomitant changes have bulked this patch out a bit:
* contextual messages attachments, which are now produced for parameterized
derived type instantiations so that the user can figure out which
instance caused a problem with a component, have been added as part
of ContextualMessages, and their implementation was debugged
* several APIs in evaluate::characteristics was changed so that a FoldingContext
is passed as an argument rather than just its intrinsic procedure table;
this affected client call sites in many files
* new tools in Evaluate/check-expression.cpp to determine when an Expr
actually is a single constant value and to validate a non-pointer
variable initializer or object component default value
* shape conformance checking has additional arguments that control
whether scalar expansion is allowed
* several now-unused functions and data members noticed and removed
* several crashes and bogus errors exposed by testing this new code
were fixed
* a -fdebug-stack-trace option to enable LLVM's stack tracing on
a crash, which might be useful in the future

TL;DR: Initialization processing does more and takes place at the right
times for all of the various kinds of things that can be initialized.

Differential Review: https://reviews.llvm.org/D92783

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[flang] Duplicate names for ac-implied-do variables erroneously cause errors

According to section 19.4, paragraph 5, the scope of an ac-implied-do variable
is the enclosing ac-implied-do. But we we

[flang] Duplicate names for ac-implied-do variables erroneously cause errors

According to section 19.4, paragraph 5, the scope of an ac-implied-do variable
is the enclosing ac-implied-do. But we were not creating new scopes upon
entry to an ac-implied-do. This was causing error messages to be erroneously
emitted.

I fixed, the code, added a test to array-constr-values.f90, added the test
folding15.f90 and corrected the test symbol05.f90.

Differential Revision: https://reviews.llvm.org/D91560

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[flang] Allow array constructor implied DO loop indices as constant expressions

When the bounds of an implied DO loop in an array constructor are
constant, the index variable of that loop is conside

[flang] Allow array constructor implied DO loop indices as constant expressions

When the bounds of an implied DO loop in an array constructor are
constant, the index variable of that loop is considered a constant
expression and can be used as such in the items in the value list
of the implied DO loop. Since the KIND type parameter values of items
in the value list can depend on the various values taken by such an
index, it is not possible to represent those values with a single
typed expression. So implement such loops by taking multiple passes
over the parse tree of the implied DO loop instead.

Differential revision: https://reviews.llvm.org/D90494

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[Flang] Checks for constraint C7110-C7115.

Added more tests.
Annotate sources and tests.
Improve error message.

Reviewed By: PeteSteinfeld

Differential Revision: https://reviews.llvm.org/D85014