:ADDPATCH fortran:
This patch supercedes the patch by Asher,
http://gcc.gnu.org/ml/gcc-patches/2007-08/msg00960.html
and by me
http://gcc.gnu.org/ml/gcc-patches/2007-08/msg00996.html
By default, gfortran currently puts local variables (with known bounds),
which are smaller than 32kbits, on the stack, variables which are
bigger are marked as static. (And automatic variables etc. are allocated
on the heap.)
Some legacy applications imply SAVE without actually specifying it; in
this case -fno-automatic (or -fmax-stack-var-size=0) has to be used.
Other legacy applications call procedures recursively without using the
RECURSIVE attribute - or the recursion happens through the backdoor via
parallelization (OpenMP, but potentially also shared-memory MPI, Posix
Threads, ...). In this case the local variables of such procedures shall
not be in static memory.
Internally, gfortran uses gfc_option.flag_max_stack_var_size = -1 for
the latter, but since "fmax-stack-var-size=" is "UInteger" thus -1
cannot be set from the command line.
This patch introduces the option -frecursive to disable static memory
for local variables; makes -fopenmp imply -frecursive and adds a couple
of warning if conflicting options have been specified. The hierarchy of
the options is:
1. Implied: stack-var-size = 32 k (implied by the default
-fmax-stack-var-size= 32k and -fautomatic)
2. -fopenmp implies: stack-var-size=-1
3. Explicitly set -fmax-stack-var-size=<n>
4. -frecursive: stack-var-size=-1
5. -fno-automatic: stack-var-size=0
Regression tested on x86_64-unknown-linux-gnu and with "make info" and
"make pdf".
Ok for the trunk?
Tobias
------------------------------------------------------------------------
2007-08-20 Asher Langton <langton2@llnl.gov>
Tobias Burnus <burnus@net-b.de>
* gfortran.h (gfc_option_t): Add flag_recursive.
* lang.opt: Add -frecursive option and update -fopenmp.
* invoke.texi (-frecursive): Document new option.
(-fopenmp,-fno-automatic,-fmax-stack-var-size): Update.
* options.c (gfc_init_options, gfc_post_options,
gfc_handle_option): Add -frecursive and modify -fopenmp.
(gfc_post_options): Add warning for conflicting flags.
2007-08-20 Asher Langton <langton2@llnl.gov>
* gfortran.dg/recursive_stack.f90: New.
* gfortran.dg/openmp_stack.f90: New.
Index: gcc/fortran/gfortran.h
===================================================================
--- gcc/fortran/gfortran.h (Revision 127641)
+++ gcc/fortran/gfortran.h (Arbeitskopie)
@@ -1863,6 +1866,7 @@ typedef struct
int flag_openmp;
int flag_sign_zero;
int flag_module_private;
+ int flag_recursive;
int fpe;
Index: gcc/fortran/lang.opt
===================================================================
--- gcc/fortran/lang.opt (Revision 127641)
+++ gcc/fortran/lang.opt (Arbeitskopie)
@@ -218,7 +218,7 @@ Set default accessibility of module enti
fopenmp
Fortran
-Enable OpenMP
+Enable OpenMP (also sets frecursive)
fpack-derived
Fortran
@@ -240,6 +240,10 @@ frecord-marker=8
Fortran RejectNegative
Use an 8-byte record marker for unformatted files
+frecursive
+Fortran
+Allocate local variables on the stack to allow indirect recursion
+
frepack-arrays
Fortran
Copy array sections into a contiguous block on procedure entry
Index: gcc/fortran/options.c
===================================================================
--- gcc/fortran/options.c (Revision 127641)
+++ gcc/fortran/options.c (Arbeitskopie)
@@ -86,7 +86,10 @@ gfc_init_options (unsigned int argc ATTR
gfc_option.flag_f2c = 0;
gfc_option.flag_second_underscore = -1;
gfc_option.flag_implicit_none = 0;
- gfc_option.flag_max_stack_var_size = 32768;
+
+ /* Default value of flag_max_stack_var_size is set in gfc_post_options. */
+ gfc_option.flag_max_stack_var_size = -2;
+
gfc_option.flag_range_check = 1;
gfc_option.flag_pack_derived = 0;
gfc_option.flag_repack_arrays = 0;
@@ -103,6 +106,7 @@ gfc_init_options (unsigned int argc ATTR
gfc_option.flag_d_lines = -1;
gfc_option.flag_openmp = 0;
gfc_option.flag_sign_zero = 1;
+ gfc_option.flag_recursive = 0;
gfc_option.fpe = 0;
@@ -290,6 +294,37 @@ gfc_post_options (const char **pfilename
if (gfc_option.flag_second_underscore == -1)
gfc_option.flag_second_underscore = gfc_option.flag_f2c;
+ if (!gfc_option.flag_automatic && gfc_option.flag_max_stack_var_size != -2
+ && gfc_option.flag_max_stack_var_size != 0)
+ gfc_warning_now ("Flag -fno-automatic overwrites -fmax-stack-var-size=%d",
+ gfc_option.flag_max_stack_var_size);
+ else if (!gfc_option.flag_automatic && gfc_option.flag_recursive)
+ gfc_warning_now ("Flag -fno-automatic overwrites -frecursive");
+ else if (!gfc_option.flag_automatic && gfc_option.flag_openmp)
+ gfc_warning_now ("Flag -fno-automatic overwrites -frecursive implied by "
+ "-fopenmp");
+ else if (gfc_option.flag_max_stack_var_size != -2
+ && gfc_option.flag_recursive)
+ gfc_warning_now ("Flag -frecursive overwrites -fmax-stack-var-size=%d",
+ gfc_option.flag_max_stack_var_size);
+ else if (gfc_option.flag_max_stack_var_size != -2
+ && gfc_option.flag_openmp)
+ gfc_warning_now ("Flag -fmax-stack-var-size=%d overwrites -frecursive "
+ "implied by -fopenmp",
+ gfc_option.flag_max_stack_var_size);
+
+ /* Implied -frecursive; implemented as -fmax-stack-var-size=-1. */
+ if (gfc_option.flag_max_stack_var_size == -2 && gfc_option.flag_openmp)
+ gfc_option.flag_max_stack_var_size = -1;
+
+ /* Set default. */
+ if (gfc_option.flag_max_stack_var_size == -2)
+ gfc_option.flag_max_stack_var_size = 32768;
+
+ /* Implement -frecursive as -fmax-stack-var-size=-1. */
+ if (gfc_option.flag_recursive)
+ gfc_option.flag_max_stack_var_size = -1;
+
/* Implement -fno-automatic as -fmax-stack-var-size=0. */
if (!gfc_option.flag_automatic)
gfc_option.flag_max_stack_var_size = 0;
@@ -698,6 +733,11 @@ gfc_handle_option (size_t scode, const c
MAX_SUBRECORD_LENGTH);
gfc_option.max_subrecord_length = value;
+ break;
+
+ case OPT_frecursive:
+ gfc_option.flag_recursive = 1;
+ break;
}
return result;
Index: gcc/fortran/invoke.texi
===================================================================
--- gcc/fortran/invoke.texi (Revision 127641)
+++ gcc/fortran/invoke.texi (Arbeitskopie)
@@ -156,7 +156,7 @@ and warnings}.
-fsecond-underscore @gol
-fbounds-check -fmax-stack-var-size=@var{n} @gol
-fpack-derived -frepack-arrays -fshort-enums -fexternal-blas @gol
--fblas-matmul-limit=@var{n}}
+-fblas-matmul-limit=@var{n} -frecursive}
@end table
@menu
@@ -296,7 +296,7 @@ and @code{c$omp}, @code{*$omp} and @code
@code{!$} conditional compilation sentinels in free form
and @code{c$}, @code{*$} and @code{!$} sentinels in fixed form,
and when linking arranges for the OpenMP runtime library to be linked
-in.
+in. The option @option{-fopenmp} implies @option{-frecursive}.
@item -frange-check
@opindex @code{frange-check}
@@ -710,10 +710,13 @@ it.
@opindex @code{fno-automatic}
@cindex @code{SAVE} statement
@cindex statement, @code{SAVE}
-Treat each program unit as if the @code{SAVE} statement was specified for
-every local variable and array referenced in it. Does not affect common
-blocks. (Some Fortran compilers provide this option under the name
-@option{-static}.)
+Treat each program unit (except those marked as RECURSIVE) as if the
+@code{SAVE} statement were specified for every local variable and array
+referenced in it. Does not affect common blocks. (Some Fortran compilers
+provide this option under the name @option{-static} or @option{-save}.)
+The default is @option{-fautomatic} which uses the stack for local