From 96d368d10456f5a599db759aab20e84a61f361f9 Mon Sep 17 00:00:00 2001 From: Nils-Christian Kempke Date: Mon, 11 Apr 2022 14:06:56 +0200 Subject: [PATCH] gdb/doc: add section about Fortran intrinsic functions and types The earlier version of this document had no sections about the available Fortran intrinsic functions or the Fortran builtin types. I added two sections 'Fortran intrinsics' and 'Fortran types' to document the available Fortran language features. The subsection 'Fortran Defaults' has been integrated into the Fortran subsection. --- gdb/doc/gdb.texinfo | 143 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 133 insertions(+), 10 deletions(-) diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index e4685cd995b..bb72d3177f8 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -17176,8 +17176,8 @@ vector data types. @subsection Fortran @cindex Fortran-specific support in @value{GDBN} -@value{GDBN} can be used to debug programs written in Fortran, but it -currently supports only the features of Fortran 77 language. +@value{GDBN} can be used to debug programs written in Fortran. Note, that not +all Fortran language features are available yet. @cindex trailing underscore, in Fortran symbols Some Fortran compilers (@sc{gnu} Fortran 77 and Fortran 95 compilers @@ -17186,12 +17186,71 @@ functions. When you debug programs compiled by those compilers, you will need to refer to variables and functions with a trailing underscore. +@cindex Fortran Defaults +Fortran symbols are usually case-insensitive, so @value{GDBN} by +default uses case-insensitive matching for Fortran symbols. You can +change that with the @samp{set case-insensitive} command, see +@ref{Symbols}, for the details. + @menu +* Fortran Types:: Fortran builtin types * Fortran Operators:: Fortran operators and expressions -* Fortran Defaults:: Default settings for Fortran +* Fortran Intrinsics:: Fortran intrinsic functions * Special Fortran Commands:: Special @value{GDBN} commands for Fortran @end menu +@node Fortran Types +@subsubsection Fortran Types + +@cindex Fortran Types + +In Fortran the primitive data-types have an associated @code{KIND} type +parameter, written as @samp{@var{type}*@var{kindparam}}, +@samp{@var{type}*@var{kindparam}}, or in the @value{GDBN}-only dialect +@samp{@var{type}_@var{kindparam}}. A concrete example would be +@samp{@code{Real*4}}, @samp{@code{Real(kind=4)}}, and @samp{@code{Real_4}}. +The kind of a type can be retrieved by using the intrinsic function +@code{KIND}, see @ref{Fortran Intrinsics}. + +Generally, the actual implementation of the @code{KIND} type parameter is +compiler specific. In @value{GDBN} the kind parameter is implemented in +accordance with its use in the @sc{gnu} @command{gfortran} compiler. Here, the +kind parameter for a given @var{type} specifies its size in memory --- a +Fortran @code{Integer*4} or @code{Integer(kind=4)} would be an integer type +occupying 4 bytes of memory. An exception to this rule is the @code{Complex} +type for which the kind of the type does not specify its entire size, but +the size of each of the two @code{Real}'s it is composed of. A +@code{Complex*4} would thus consist of two @code{Real*4}s and occupy 8 bytes +of memory. + +For every type there is also a default kind associated with it, e.g.@ +@code{Integer} in @value{GDBN} will internally be an @code{Integer*4} (see the +table below for default types). The default types are the same as in @sc{gnu} +compilers but note, that the @sc{gnu} default types can actually be changed by +compiler flags such as @option{-fdefault-integer-8} and +@option{-fdefault-real-8}. + +Not every kind parameter is valid for every type and in @value{GDBN} the +following type kinds are available. + +@table @code +@item Integer +@code{Integer*1}, @code{Integer*2}, @code{Integer*4}, @code{Integer*8}, and +@code{Integer} = @code{Integer*4}. + +@item Logical +@code{Logical*1}, @code{Logical*2}, @code{Logical*4}, @code{Logical*8}, and +@code{Logical} = @code{Logical*4}. + +@item Real +@code{Real*4}, @code{Real*8}, @code{Real*16}, and @code{Real} = @code{Real*4}. + +@item Complex +@code{Complex*4}, @code{Complex*8}, @code{Complex*16}, and @code{Complex} = +@code{Complex*4}. + +@end table + @node Fortran Operators @subsubsection Fortran Operators and Expressions @@ -17221,15 +17280,79 @@ to set breakpoints on subroutines nested in modules or in other subroutines (internal subroutines). @end table -@node Fortran Defaults -@subsubsection Fortran Defaults +@node Fortran Intrinsics +@subsubsection Fortran Intrinsics -@cindex Fortran Defaults +@cindex Fortran Intrinsics -Fortran symbols are usually case-insensitive, so @value{GDBN} by -default uses case-insensitive matches for Fortran symbols. You can -change that with the @samp{set case-insensitive} command, see -@ref{Symbols}, for the details. +Fortran provides a large set of intrinsic procedures. @value{GDBN} implements +an incomplete subset of those procedures and their overloads. Some of these +procedures take an optional @code{KIND} parameter, see @ref{Fortran Types}. + +@table @code +@item ABS(@var{a}) +Computes the absolute value of its argument @var{a}. Currently not supported +for @code{Complex} arguments. + +@item ALLOCATE(@var{array}) +Returns whether @var{array} is allocated or not. + +@item ASSOCIATED(@var{pointer} [, @var{target}]) +Returns the association status of the pointer @var{pointer} or, if @var{target} +is present, whether @var{pointer} is associated with the target @var{target}. + +@item CEILING(@var{a} [, @var{kind}]) +Computes the least integer greater than or equal to @var{a}. The optional +parameter @var{kind} specifies the kind of the return type +@code{Integer(@var{kind})}. + +@item CMPLX(@var{x} [, @var{y} [, @var{kind}]]) +Returns a complex number where @var{x} is converted to the real component. If +@var{y} is present it is converted to the imaginary component. If @var{y} is +not present then the imaginary component is set to @code{0.0} except if @var{x} +itself is of @code{Complex} type. The optional parameter @var{kind} specifies +the kind of the return type @code{Complex(@var{kind})}. + +@item FLOOR(@var{a} [, @var{kind}]) +Computes the greatest integer less than or equal to @var{a}. The optional +parameter @var{kind} specifies the kind of the return type +@code{Integer(@var{kind})}. + +@item KIND(@var{a}) +Returns the kind value of the argument @var{a}, see @ref{Fortran Types}. + +@item LBOUND(@var{array} [, @var{dim} [, @var{kind}]]) +Returns the lower bounds of an @var{array}, or a single lower bound along the +@var{dim} dimension if present. The optional parameter @var{kind} specifies +the kind of the return type @code{Integer(@var{kind})}. + +@item LOC(@var{x}) +Returns the address of @var{x} as an @code{Integer}. + +@item MOD(@var{a}, @var{p}) +Computes the remainder of the division of @var{a} by @var{p}. + +@item MODULO(@var{a}, @var{p}) +Computes the @var{a} modulo @var{p}. + +@item RANK(@var{a}) +Returns the rank of a scalar or array (scalars have rank @code{0}). + +@item SHAPE(@var{a}) +Returns the shape of a scalar or array (scalars have shape @samp{()}). + +@item SIZE(@var{array}[, @var{dim} [, @var{kind}]]) +Returns the extent of @var{array} along a specified dimension @var{dim}, or the +total number of elements in @var{array} if @var{dim} is absent. The optional +parameter @var{kind} specifies the kind of the return type +@code{Integer(@var{kind})}. + +@item UBOUND(@var{array} [, @var{dim} [, @var{kind}]]) +Returns the upper bounds of an @var{array}, or a single upper bound along the +@var{dim} dimension if present. The optional parameter @var{kind} specifies +the kind of the return type @code{Integer(@var{kind})}. + +@end table @node Special Fortran Commands @subsubsection Special Fortran Commands -- 2.30.2