Please find attached a proposed legacy extension to allow dimensions to
be omitted when referring to an array element. The declared lower bound
being used by default.
This feature is known to exist in earlier compilers and is believed to
be a DEC extension and is definitely supported by flang. As it is
non-standard the feature will only be enabled using
-fdec-add-missing-indexes (and -fdec), a warning will be produced when
used. As warnings are commonly regarded as errors in build environments
-Wno-missing-index has be provided to suppress the warning if needed.
Commit message:
Fortran : Fill in missing array dimensions using the lower bound
Use -fdec-add-missing-indexes to enable feature. Also enabled by fdec.
A warning that the lower bound is being used for a mission dimension
is output unless suppressed by using -Wno-missing-index.
2020-06-25 Jim MacArthur <jim.macart...@codethink.co.uk>
Mark Eggleston <markeggles...@gcc.gnu.org>
gcc/fortran/
* lang.opt: Add options -Wmissing-index and
-fdec-add-missing-indexes.
* options.c (set_dec_flags): Add SET_BITFLAG for new option.
* resolve.c (compare_spec_to_ref): If the flag is set and
the number of dimension is less than the rank use the lower
bound for the missing dimensions.
2020-06-25 Jim MacArthur <jim.macart...@codethink.co.uk>
Mark Eggleston <markeggles...@gcc.gnu.org>
gcc/testsuite/
* gfortran.dg/array_6.f90: New test.
* gfortran.dg/array_7.f90: New test.
* gfortran.dg/array_8.f90: New test.
* gfortran.dg/array_9.f90: New test.
--
https://www.codethink.co.uk/privacy.html
>From 3ab6576ec34dd14cac10a52a1a7e08c176ebc357 Mon Sep 17 00:00:00 2001
From: Mark Eggleston <markeggles...@gcc.gnu.org>
Date: Mon, 3 Feb 2020 10:56:36 +0000
Subject: [PATCH] Fortran : Fill in missing array dimensions using the lower
bound
Use -fdec-add-missing-indexes to enable feature. Also enabled by fdec.
A warning that the lower bound is being used for a mission dimension
is output unless suppressed by using -Wno-missing-index.
2020-06-24 Jim MacArthur <jim.macart...@codethink.co.uk>
Mark Eggleston <markeggles...@gcc.gnu.org>
gcc/fortran/
* lang.opt: Add options -Wmissing-index and
-fdec-add-missing-indexes.
* options.c (set_dec_flags): Add SET_BITFLAG for new option.
* resolve.c (compare_spec_to_ref): If the flag is set and
the number of dimension is less than the rank use the lower
bound for the missing dimensions.
2020-06-24 Jim MacArthur <jim.macart...@codethink.co.uk>
Mark Eggleston <markeggles...@gcc.gnu.org>
gcc/testsuite/
* gfortran.dg/array_6.f90: New test.
* gfortran.dg/array_7.f90: New test.
* gfortran.dg/array_8.f90: New test.
* gfortran.dg/array_9.f90: New test.
---
gcc/fortran/invoke.texi | 40 +++++++++++++++++++++++------------
gcc/fortran/lang.opt | 8 +++++++
gcc/fortran/options.c | 1 +
gcc/fortran/resolve.c | 20 ++++++++++++++++++
gcc/testsuite/gfortran.dg/array_6.f90 | 24 +++++++++++++++++++++
gcc/testsuite/gfortran.dg/array_7.f90 | 24 +++++++++++++++++++++
gcc/testsuite/gfortran.dg/array_8.f90 | 24 +++++++++++++++++++++
gcc/testsuite/gfortran.dg/array_9.f90 | 24 +++++++++++++++++++++
8 files changed, 151 insertions(+), 14 deletions(-)
create mode 100644 gcc/testsuite/gfortran.dg/array_6.f90
create mode 100644 gcc/testsuite/gfortran.dg/array_7.f90
create mode 100644 gcc/testsuite/gfortran.dg/array_8.f90
create mode 100644 gcc/testsuite/gfortran.dg/array_9.f90
diff --git a/gcc/fortran/invoke.texi b/gcc/fortran/invoke.texi
index 052d3178244..989011af868 100644
--- a/gcc/fortran/invoke.texi
+++ b/gcc/fortran/invoke.texi
@@ -118,16 +118,17 @@ by type. Explanations are in the following sections.
@xref{Fortran Dialect Options,,Options controlling Fortran dialect}.
@gccoptlist{-fall-intrinsics -fallow-argument-mismatch -fallow-invalid-boz @gol
-fbackslash -fcray-pointer -fd-lines-as-code -fd-lines-as-comments @gol
--fdec -fdec-char-conversions -fdec-structure -fdec-intrinsic-ints @gol
--fdec-static -fdec-math -fdec-include -fdec-format-defaults @gol
--fdec-blank-format-item -fdefault-double-8 -fdefault-integer-8 @gol
--fdefault-real-8 -fdefault-real-10 -fdefault-real-16 -fdollar-ok @gol
--ffixed-line-length-@var{n} -ffixed-line-length-none -fpad-source @gol
--ffree-form -ffree-line-length-@var{n} -ffree-line-length-none @gol
--fimplicit-none -finteger-4-integer-8 -fmax-identifier-length @gol
--fmodule-private -ffixed-form -fno-range-check -fopenacc -fopenmp @gol
--freal-4-real-10 -freal-4-real-16 -freal-4-real-8 -freal-8-real-10 @gol
--freal-8-real-16 -freal-8-real-4 -std=@var{std} -ftest-forall-temp
+-fdec -fdec-add-missing-indexes -fdec-char-conversions -fdec-structure @gol
+-fdec-intrinsic-ints -fdec-static -fdec-math -fdec-include @gol
+-fdec-format-defaults -fdec-blank-format-item -fdefault-double-8 @gol
+-fdefault-integer-8 -fdefault-real-8 -fdefault-real-10 -fdefault-real-16 @gol
+-fdollar-ok -ffixed-line-length-@var{n} -ffixed-line-length-none @gol
+-fpad-source -ffree-form -ffree-line-length-@var{n} @gol
+-ffree-line-length-none -fimplicit-none -finteger-4-integer-8 @gol
+-fmax-identifier-length -fmodule-private -ffixed-form -fno-range-check @gol
+-fopenacc -fopenmp -freal-4-real-10 -freal-4-real-16 -freal-4-real-8 @gol
+-freal-8-real-10 -freal-8-real-16 -freal-8-real-4 -std=@var{std} @gol
+-ftest-forall-temp
}
@item Preprocessing Options
@@ -149,7 +150,7 @@ and warnings}.
-Wc-binding-type -Wcharacter-truncation -Wconversion @gol
-Wdo-subscript -Wfunction-elimination -Wimplicit-interface @gol
-Wimplicit-procedure -Wintrinsic-shadow -Wuse-without-only @gol
--Wintrinsics-std -Wline-truncation -Wno-align-commons @gol
+-Wintrinsics-std -Wline-truncation -Wno-align-commons -Wno-missing-index@gol
-Wno-overwrite-recursive -Wno-tabs -Wreal-q-constant -Wsurprising @gol
-Wunderflow -Wunused-parameter -Wrealloc-lhs -Wrealloc-lhs-all @gol
-Wfrontend-loop-interchange -Wtarget-lifetime -fmax-errors=@var{n} @gol
@@ -274,14 +275,20 @@ For details on GNU Fortran's implementation of these extensions see the
full documentation.
Other flags enabled by this switch are:
-@option{-fdollar-ok} @option{-fcray-pointer} @option{-fdec-char-conversions}
-@option{-fdec-structure} @option{-fdec-intrinsic-ints} @option{-fdec-static}
-@option{-fdec-math} @option{-fdec-include} @option{-fdec-blank-format-item}
+@option{-fdollar-ok} @option{-fcray-pointer} @option{-fdec-add-missing-indexes}
+@option{-fdec-char-conversions} @option{-fdec-structure}
+@option{-fdec-intrinsic-ints} @option{-fdec-static} @option{-fdec-math}
+@option{-fdec-include} @option{-fdec-blank-format-item}
@option{-fdec-format-defaults}
If @option{-fd-lines-as-code}/@option{-fd-lines-as-comments} are unset, then
@option{-fdec} also sets @option{-fd-lines-as-comments}.
+@item -fdec-add-missing-indexes
+@opindex @code{fdec-add-missing-indexes}
+Enable the use of the lower bound of an index when there are fewer indexes
+than the rank of the variable.
+
@item -fdec-char-conversions
@opindex @code{fdec-char-conversions}
Enable the use of character literals in assignments and @code{DATA} statements
@@ -1005,6 +1012,11 @@ it as @code{EXTERNAL} procedure because of this. @option{-fall-intrinsics} can
be used to never trigger this behavior and always link to the intrinsic
regardless of the selected standard.
+@item -Wno-missing-index
+@opindex @code{Wmissing-index}
+@cindex warnings
+Do not warn when the lower bound is used as the index of an unspecified dimension.
+
@item -Wno-overwrite-recursive
@opindex @code{Woverwrite-recursive}
@cindex warnings, overwrite recursive
diff --git a/gcc/fortran/lang.opt b/gcc/fortran/lang.opt
index da4b1aa879a..3885f676dda 100644
--- a/gcc/fortran/lang.opt
+++ b/gcc/fortran/lang.opt
@@ -281,6 +281,10 @@ Wmissing-include-dirs
Fortran
; Documented in C/C++
+Wmissing-index
+Fortran Var(warn_missing_index) Warning Init(1)
+Warn that the lower bound of a missing index will be used.
+
Wuse-without-only
Fortran Var(warn_use_without_only) Warning
Warn about USE statements that have no ONLY qualifier.
@@ -456,6 +460,10 @@ fdec
Fortran Var(flag_dec)
Enable all DEC language extensions.
+fdec-add-missing-indexes
+Fortran Var(flag_dec_add_missing_indexes)
+Enable the addition of missing indexes using their lower bounds.
+
fdec-blank-format-item
Fortran Var(flag_dec_blank_format_item)
Enable the use of blank format items in format strings.
diff --git a/gcc/fortran/options.c b/gcc/fortran/options.c
index d844fa93115..5c660621a5e 100644
--- a/gcc/fortran/options.c
+++ b/gcc/fortran/options.c
@@ -77,6 +77,7 @@ set_dec_flags (int value)
SET_BITFLAG (flag_dec_format_defaults, value, value);
SET_BITFLAG (flag_dec_blank_format_item, value, value);
SET_BITFLAG (flag_dec_char_conversions, value, value);
+ SET_BITFLAG (flag_dec_add_missing_indexes, value, value);
}
/* Finalize DEC flags. */
diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index c53b312f7ed..7ce5741385d 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -4711,6 +4711,26 @@ compare_spec_to_ref (gfc_array_ref *ar)
if (ar->type == AR_FULL)
return true;
+ if (flag_dec_add_missing_indexes && as->rank > ar->dimen)
+ {
+ /* Add in the missing dimensions, assuming they are the lower bound
+ of that dimension if not specified. */
+ gfc_warning (OPT_Wmissing_index, "Using the lower bound for "
+ "unspecified dimensions in array reference at %L",
+ &ar->where);
+ /* Other parts of the code iterate ar->start and ar->end from 0 to
+ ar->dimen, so it is safe to assume slots from ar->dimen upwards
+ are unused (i.e. there are no gaps; the specified indexes are
+ contiguous and start at zero. */
+ for(int j = ar->dimen; j <= as->rank; j++)
+ {
+ ar->start[j] = gfc_copy_expr (as->lower[j]);
+ ar->end[j] = gfc_copy_expr (as->lower[j]);
+ ar->dimen_type[j] = DIMEN_ELEMENT;
+ }
+ ar->dimen = as->rank;
+ }
+
if (as->rank != ar->dimen)
{
gfc_error ("Rank mismatch in array reference at %L (%d/%d)",
diff --git a/gcc/testsuite/gfortran.dg/array_6.f90 b/gcc/testsuite/gfortran.dg/array_6.f90
new file mode 100644
index 00000000000..73a0b627c32
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/array_6.f90
@@ -0,0 +1,24 @@
+! { dg-do run }
+! { dg-options "-fdec" }
+!
+! Checks that under-specified arrays (referencing arrays with fewer
+! dimensions than the array spec) generates a warning.
+!
+! Contributed by Jim MacArthur <jim.macart...@codethink.co.uk>
+! Updated by Mark Eggleston <mark.eggles...@codethink.co.uk>
+!
+
+program under_specified_array
+ integer chessboard(8,8)
+ integer chessboard3d(8,8,3:5)
+ chessboard(3,1) = 5
+ chessboard(3,2) = 55
+ chessboard3d(4,1,3) = 6
+ chessboard3d(4,1,4) = 66
+ chessboard3d(4,4,3) = 7
+ chessboard3d(4,4,4) = 77
+
+ if (chessboard(3).ne.5) stop 1 ! { dg-warning "Using the lower bound for unspecified dimensions in array reference" }
+ if (chessboard3d(4).ne.6) stop 2 ! { dg-warning "Using the lower bound for unspecified dimensions in array reference" }
+ if (chessboard3d(4,4).ne.7) stop 3 ! { dg-warning "Using the lower bound for unspecified dimensions in array reference" }
+end program
diff --git a/gcc/testsuite/gfortran.dg/array_7.f90 b/gcc/testsuite/gfortran.dg/array_7.f90
new file mode 100644
index 00000000000..924057c8ac2
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/array_7.f90
@@ -0,0 +1,24 @@
+! { dg-do run }
+! { dg-options "-fdec-add-missing-indexes" }
+!
+! Checks that under-specified arrays (referencing arrays with fewer
+! dimensions than the array spec) generates a warning.
+!
+! Contributed by Jim MacArthur <jim.macart...@codethink.co.uk>
+! Updated by Mark Eggleston <mark.eggles...@codethink.co.uk>
+!
+
+program under_specified_array
+ integer chessboard(8,8)
+ integer chessboard3d(8,8,3:5)
+ chessboard(3,1) = 5
+ chessboard(3,2) = 55
+ chessboard3d(4,1,3) = 6
+ chessboard3d(4,1,4) = 66
+ chessboard3d(4,4,3) = 7
+ chessboard3d(4,4,4) = 77
+
+ if (chessboard(3).ne.5) stop 1 ! { dg-warning "Using the lower bound for unspecified dimensions in array reference" }
+ if (chessboard3d(4).ne.6) stop 2 ! { dg-warning "Using the lower bound for unspecified dimensions in array reference" }
+ if (chessboard3d(4,4).ne.7) stop 3 ! { dg-warning "Using the lower bound for unspecified dimensions in array reference" }
+end program
diff --git a/gcc/testsuite/gfortran.dg/array_8.f90 b/gcc/testsuite/gfortran.dg/array_8.f90
new file mode 100644
index 00000000000..66573a0a474
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/array_8.f90
@@ -0,0 +1,24 @@
+! { dg-do compile }
+! { dg-options "-fdec -fno-dec-add-missing-indexes" }
+!
+! Checks that under-specified arrays (referencing arrays with fewer
+! dimensions than the array spec) generates a warning.
+!
+! Contributed by Jim MacArthur <jim.macart...@codethink.co.uk>
+! Updated by Mark Eggleston <mark.eggles...@codethink.co.uk>
+!
+
+program under_specified_array
+ integer chessboard(8,8)
+ integer chessboard3d(8,8,3:5)
+ chessboard(3,1) = 5
+ chessboard(3,2) = 55
+ chessboard3d(4,1,3) = 6
+ chessboard3d(4,1,4) = 66
+ chessboard3d(4,4,3) = 7
+ chessboard3d(4,4,4) = 77
+
+ if (chessboard(3).ne.5) stop 1 ! { dg-error "Rank mismatch" }
+ if (chessboard3d(4).ne.6) stop 2 ! { dg-error "Rank mismatch" }
+ if (chessboard3d(4,4).ne.7) stop 3 ! { dg-error "Rank mismatch" }
+end program
diff --git a/gcc/testsuite/gfortran.dg/array_9.f90 b/gcc/testsuite/gfortran.dg/array_9.f90
new file mode 100644
index 00000000000..17cce5347ed
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/array_9.f90
@@ -0,0 +1,24 @@
+! { dg-do run }
+! { dg-options "-fdec -Wno-missing-index" }
+!
+! Checks that under-specified arrays (referencing arrays with fewer
+! dimensions than the array spec) generates a warning.
+!
+! Contributed by Jim MacArthur <jim.macart...@codethink.co.uk>
+! Updated by Mark Eggleston <mark.eggles...@codethink.co.uk>
+!
+
+program under_specified_array
+ integer chessboard(8,8)
+ integer chessboard3d(8,8,3:5)
+ chessboard(3,1) = 5
+ chessboard(3,2) = 55
+ chessboard3d(4,1,3) = 6
+ chessboard3d(4,1,4) = 66
+ chessboard3d(4,4,3) = 7
+ chessboard3d(4,4,4) = 77
+
+ if (chessboard(3).ne.5) stop 1
+ if (chessboard3d(4).ne.6) stop 2
+ if (chessboard3d(4,4).ne.7) stop 3
+end program
--
2.11.0
