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.

4 files changed, 6 insertions, 36 deletions

diff --git a/sim/ppc/ChangeLog b/sim/ppc/ChangeLog
index 3926430..49b3e66 100644
--- a/sim/ppc/ChangeLog
+++ b/sim/ppc/ChangeLog
@@ -1,5 +1,11 @@
 2021-06-12  Mike Frysinger  <vapier@gentoo.org>
 
+	* Makefile.in: Delete ALIGNMENT_CFLAGS.
+	* configure.ac: Delete sim-alignment.
+	* configure: Regenerate.
+
+2021-06-12  Mike Frysinger  <vapier@gentoo.org>
+
 	* configure.ac: Delete calls to ACX_PKGVERSION & ACX_BUGURL.
 	* aclocal.m4, config.in, configure: Regenerate.
 
diff --git a/sim/ppc/Makefile.in b/sim/ppc/Makefile.in
index 1996e13..5d0dd74 100644
--- a/sim/ppc/Makefile.in
+++ b/sim/ppc/Makefile.in
@@ -79,7 +79,6 @@ XOR_ENDIAN_CFLAGS = @sim_xor_endian@
 BITSIZE_CFLAGS = @sim_bitsize@
 HOSTBITSIZE_CFLAGS = @sim_hostbitsize@
 TIMEBASE_CFLAGS = @sim_timebase@
-ALIGNMENT_CFLAGS = @sim_alignment@
 FLOAT_CFLAGS = @sim_float@
 RESERVED_CFLAGS = @sim_reserved@
 MONITOR_CFLAGS = @sim_monitor@
@@ -95,7 +94,6 @@ CONFIG_CFLAGS = \
   $(BITSIZE_CFLAGS) \
   $(HOSTBITSIZE_CFLAGS) \
   $(TIMEBASE_CFLAGS) \
-  $(ALIGNMENT_CFLAGS) \
   $(FLOAT_CFLAGS) \
   $(RESERVED_CFLAGS) \
   $(MONITOR_CFLAGS) \
diff --git a/sim/ppc/configure b/sim/ppc/configure
index 5f0f779..c7dd1b4 100755
--- a/sim/ppc/configure
+++ b/sim/ppc/configure
@@ -633,7 +633,6 @@ sim_model
 sim_monitor
 sim_reserved
 sim_float
-sim_alignment
 sim_timebase
 sim_hostbitsize
 sim_bitsize
@@ -742,7 +741,6 @@ SHELL'
 ac_subst_files=''
 ac_user_opts='
 enable_option_checking
-enable_sim_alignment
 enable_sim_assert
 enable_sim_bitsize
 enable_sim_config
@@ -1400,7 +1398,6 @@ Optional Features:
   --disable-option-checking  ignore unrecognized --enable/--with options
   --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
-  --enable-sim-alignment=align		Specify strict or nonstrict alignment.
   --enable-sim-assert			Specify whether to perform random assertions.
   --enable-sim-bitsize=n		Specify target bitsize (32 or 64).
   --enable-sim-config=file		Override default config file
@@ -3120,22 +3117,6 @@ $as_echo "$LINGUAS" >&6; }
 fi
 
 
-# Check whether --enable-sim-alignment was given.
-if test "${enable_sim_alignment+set}" = set; then :
-  enableval=$enable_sim_alignment; case "${enableval}" in
-  yes | strict | STRICT)	sim_alignment="-DWITH_ALIGNMENT=STRICT_ALIGNMENT";;
-  no | nonstrict | NONSTRICT)	sim_alignment="-DWITH_ALIGNMENT=NONSTRICT_ALIGNMENT";;
-  0 | default | DEFAULT)	sim_alignment="-DWITH_ALIGNMENT=0";;
-  *)				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
-  sim_alignment=""
-fi
-
-
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to enable sim asserts" >&5
 $as_echo_n "checking whether to enable sim asserts... " >&6; }
 sim_assert="1"
@@ -5179,7 +5160,6 @@ fi
 
 
 
-
 ac_config_files="$ac_config_files Makefile"
 
 ac_config_commands="$ac_config_commands default"
diff --git a/sim/ppc/configure.ac b/sim/ppc/configure.ac
index 5697345..3b93bee 100644
--- a/sim/ppc/configure.ac
+++ b/sim/ppc/configure.ac
@@ -19,19 +19,6 @@ ALL_LINGUAS=
 ZW_GNU_GETTEXT_SISTER_DIR(../../intl)
 
 
-AC_ARG_ENABLE(sim-alignment,
-[  --enable-sim-alignment=align		Specify strict or nonstrict alignment.],
-[case "${enableval}" in
-  yes | strict | STRICT)	sim_alignment="-DWITH_ALIGNMENT=STRICT_ALIGNMENT";;
-  no | nonstrict | NONSTRICT)	sim_alignment="-DWITH_ALIGNMENT=NONSTRICT_ALIGNMENT";;
-  0 | default | DEFAULT)	sim_alignment="-DWITH_ALIGNMENT=0";;
-  *)				AC_MSG_ERROR("Unknown value $enableval passed to --enable-sim-alignment"); sim_alignment="";;
-esac
-if test x"$silent" != x"yes" && test x"$sim_alignment" != x""; then
-  echo "Setting alignment flags = $sim_alignment" 6>&1
-fi],[sim_alignment=""])dnl
-
-
 AC_MSG_CHECKING([whether to enable sim asserts])
 sim_assert="1"
 AC_ARG_ENABLE(sim-assert,
@@ -818,7 +805,6 @@ AC_SUBST(sim_igen_smp)
 AC_SUBST(sim_bitsize)
 AC_SUBST(sim_hostbitsize)
 AC_SUBST(sim_timebase)
-AC_SUBST(sim_alignment)
 AC_SUBST(sim_float)
 AC_SUBST(sim_reserved)
 AC_SUBST(sim_monitor)