Most Fortran compilers accept the following benign extension,
and it appears in some applications:
SUBROUTINE FOO(A,N)
IMPLICIT NONE
REAL A(N) ! N is used before being typed
INTEGER N
END
Allow it in f18 only for default integer scalar dummy arguments.
Differential Revesion: https://reviews.llvm.org/D96982
Fortran 2018 explicitly permits an ignored type declaration
for the result of a generic intrinsic function. See the comment
added to Semantics/expression.cpp for an explanation of why this
is somewhat dangerous and worthy of a warning.
Differential Revision: https://reviews.llvm.org/D96879
Legacy Fortran implementations support an alternative form of the
PARAMETER statement; it differs syntactically from the standard's
PARAMETER statement by lacking parentheses, and semantically by
using the type and shape of the initialization expression to define
the attributes of the named constant. (GNU Fortran gets that part
wrong; Intel Fortran and nvfortran have full support.)
This patch disables the old style PARAMETER statement by default, as
it is syntactically ambiguous with conforming assignment statements;
adds a new "-falternative-parameter-statement" option to enable it;
and implements it correctly when enabled.
Fixes https://bugs.llvm.org/show_bug.cgi?id=48774, in which a user
tripped over the syntactic ambiguity.
Differential Revision: https://reviews.llvm.org/D95697
STORAGE_SIZE() is a standard inquiry intrinsic (size in bits
of an array element of the same type as the argument); SIZEOF()
is a common extension that returns the size in bytes of its
argument; C_SIZEOF() is a renaming of SIZEOF() in module ISO_C_BINDING.
STORAGE_SIZE() and SIZEOF() are implemented via rewrites to
expressions; these expressions will be constant when the necessary
type parameters and bounds are also constant.
Code to calculate the sizes of types (with and without alignment)
was isolated into Evaluate/type.* and /characteristics.*.
Code in Semantics/compute-offsets.* to calculate sizes and alignments
of derived types' scopes was exposed so that it can be called at type
instantiation time (earlier than before) so that these inquiry intrinsics
could be called from specification expressions.
Differential Revision: https://reviews.llvm.org/D93322
Add a new index page to be the Flang documentation mainpage instead of
Overview.md, which jumps straight into the compiler Design. The index file
needs to be in .rst format to use the toctree directive to create table of
contents.
Also use the sphinx_markdown_tables extension to generate html tables form
markdown.
A number of additional style changes to the existing docs were needed to make
this work well:
* Convert all headings to the # style, which works better with toctree's
titlesonly option. Ensure that there is only one top-level heading per
document.
* Add a title to documents that don't have one for rendering on the index.
* Convert the grammar docs from .txt to .md. for better rendering
* Fixed broken link to a section in another document - sphinx does not seem to
support anchor links in markdown files.
Depends on D87226
Reviewed By: sameeranjoshi
Differential Revision: https://reviews.llvm.org/D87242
peter klausler