sim: overhaul alignment settings management

Currently, the sim-config module will abort if alignment settings
haven't been specified by the port's configure.ac.  This is a bit
weird when we've allowed SIM_AC_OPTION_ALIGNMENT to seem like it's
optional to use.  Thus everyone invokes it.

There are 4 alignment settings, but really only 2 matters: strict
and nonstrict.  The "mixed" setting is just the default ("unset"),
and "forced" isn't used directly by anyone (it's available as a
runtime option for some ports).

The m4 macro has 2 args: the "wire" settings (which represents the
hardwired port behavior), and the default settings (which are used
if nothing else is specified).  If none are specified, then the
build won't work (see above as if SIM_AC_OPTION_ALIGNMENT wasn't
called).  If default settings are provided, then that is used, but
we allow the user to override at runtime.  Otherwise, the "wire"
settings are used and user runtime options to change are ignored.

Most ports specify a default, or set the "wire" to nonstrict.  A
few set "wire" to strict, but it's not clear that's necessary as
it doesn't make the code behavior, by default, any different.  It
might make things a little faster, but we should provide the user
the choice of the compromises to make: force a specific mode at
compile time for faster runtime, or allow the choice at runtime.
More likely it seems like an oversight when these ports were
initially created, and/or copied & pasted from existing ports.

With all that backstory, let's get to what this commit does.

First kill off the idea of a compile-time default alignment and
set it to nonstrict in the common code.  For any ports that want
strict alignment by default, that code is moved to sim_open while
initializing the sim.  That means WITH_DEFAULT_ALIGNMENT can be
completely removed.

Moving the default alignment to the runtime also allows removal
of setting the "wire" settings at configure time.  Which allows
removing of all arguments to SIM_AC_OPTION_ALIGNMENT and moving
that call to common code.

The macro logic can be reworked to not pass WITH_ALIGNMENT as -D
CPPFLAG and instead move it to config.h.

All of these taken together mean we can hoist the macro up to the
top level and share it among all sims so behavior is consistent
among all the ports.
This commit is contained in:
Mike Frysinger
2021-06-07 00:54:20 -04:00
parent 6dd65fc048
commit ba307cddcf
136 changed files with 334 additions and 1616 deletions

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@@ -1,3 +1,8 @@
2021-06-12 Mike Frysinger <vapier@gentoo.org>
* configure.ac: Delete call to SIM_AC_OPTION_ALIGNMENT.
* interp.c (sim_open):
2021-06-12 Mike Frysinger <vapier@gentoo.org>
* aclocal.m4, config.in, configure: Regenerate.

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@@ -110,7 +110,6 @@ m4_include([../../ltsugar.m4])
m4_include([../../ltversion.m4])
m4_include([../../lt~obsolete.m4])
m4_include([../m4/sim_ac_common.m4])
m4_include([../m4/sim_ac_option_alignment.m4])
m4_include([../m4/sim_ac_option_endian.m4])
m4_include([../m4/sim_ac_option_hardware.m4])
m4_include([../m4/sim_ac_option_inline.m4])

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@@ -636,6 +636,7 @@ sim_default_model
sim_scache
sim_float
sim_bitsize
sim_alignment
cgen_breaks
MAINT
MAINTAINER_MODE_FALSE
@@ -753,8 +754,7 @@ sim_inline
sim_hw
sim_hw_objs
sim_hw_cflags
sim_endian
sim_alignment'
sim_endian'
ac_subst_files=''
ac_user_opts='
enable_option_checking
@@ -769,7 +769,6 @@ enable_libtool_lock
enable_maintainer_mode
enable_sim_inline
enable_sim_endian
enable_sim_alignment
enable_werror
enable_build_warnings
enable_sim_build_warnings
@@ -1414,9 +1413,6 @@ Optional Features:
Specify which functions should be inlined
--enable-sim-endian=endian
Specify target byte endian orientation
--enable-sim-alignment=align
Specify strict, nonstrict or forced alignment of
memory accesses
--enable-werror treat compile warnings as errors
--enable-build-warnings enable build-time compiler warnings if gcc is used
--enable-sim-build-warnings
@@ -10748,7 +10744,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
#line 10751 "configure"
#line 10747 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -10854,7 +10850,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
#line 10857 "configure"
#line 10853 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -11196,52 +11192,6 @@ else
fi
fi
wire_alignment="STRICT_ALIGNMENT"
default_alignment="STRICT_ALIGNMENT"
# Check whether --enable-sim-alignment was given.
if test "${enable_sim_alignment+set}" = set; then :
enableval=$enable_sim_alignment; case "${enableval}" in
strict | STRICT) sim_alignment="-DWITH_ALIGNMENT=STRICT_ALIGNMENT";;
nonstrict | NONSTRICT) sim_alignment="-DWITH_ALIGNMENT=NONSTRICT_ALIGNMENT";;
forced | FORCED) sim_alignment="-DWITH_ALIGNMENT=FORCED_ALIGNMENT";;
yes) if test x"$wire_alignment" != x; then
sim_alignment="-DWITH_ALIGNMENT=${wire_alignment}"
else
if test x"$default_alignment" != x; then
sim_alignment="-DWITH_ALIGNMENT=${default_alignment}"
else
echo "No hard-wired alignment for target $target" 1>&6
sim_alignment="-DWITH_ALIGNMENT=0"
fi
fi;;
no) if test x"$default_alignment" != x; then
sim_alignment="-DWITH_DEFAULT_ALIGNMENT=${default_alignment}"
else
if test x"$wire_alignment" != x; then
sim_alignment="-DWITH_DEFAULT_ALIGNMENT=${wire_alignment}"
else
echo "No default alignment for target $target" 1>&6
sim_alignment="-DWITH_DEFAULT_ALIGNMENT=0"
fi
fi;;
*) as_fn_error $? "\"Unknown value $enableval passed to --enable-sim-alignment\"" "$LINENO" 5; sim_alignment="";;
esac
if test x"$silent" != x"yes" && test x"$sim_alignment" != x""; then
echo "Setting alignment flags = $sim_alignment" 6>&1
fi
else
if test x"$default_alignment" != x; then
sim_alignment="-DWITH_DEFAULT_ALIGNMENT=${default_alignment}"
else
if test x"$wire_alignment" != x; then
sim_alignment="-DWITH_ALIGNMENT=${wire_alignment}"
else
sim_alignment=
fi
fi
fi
# Check whether --enable-werror was given.

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@@ -5,6 +5,5 @@ AC_CONFIG_MACRO_DIRS([../m4 ../.. ../../config])
SIM_AC_COMMON
SIM_AC_OPTION_ENDIAN(LITTLE)
SIM_AC_OPTION_ALIGNMENT(STRICT_ALIGNMENT,STRICT_ALIGNMENT)
SIM_AC_OUTPUT

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@@ -82,6 +82,9 @@ sim_open (SIM_OPEN_KIND kind, host_callback *callback,
int i;
SIM_DESC sd = sim_state_alloc (kind, callback);
/* Set default options before parsing user options. */
current_alignment = STRICT_ALIGNMENT;
/* The cpu data is kept in a separately allocated chunk of memory. */
if (sim_cpu_alloc_all (sd, 1) != SIM_RC_OK)
{