From 401722dcd398760d2effc38a592ceab2bc4fc06e Mon Sep 17 00:00:00 2001
Message-Id: <401722dcd398760d2effc38a592ceab2bc4fc06e.1715898438.git.mdw@distorted.org.uk>
From: Mark Wooding <mdw@chiark.greenend.org.uk>
Date: Wed, 5 Jul 2017 22:08:11 +0100
Subject: [PATCH] configure.ac: Delay checking the assembler until we know the
 target CPU.
Organization: Straylight/Edgeware

From: Mark Wooding <mdw@distorted.org.uk>

It turns out that assemblers are deficient in target-specific ways, so
we have to figure out what the target is like before we can probe for
the brokenness.  Reorder things so that this is possible.  No functional
change.
---
 configure.ac | 56 ++++++++++++++++++++++++++--------------------------
 1 file changed, 28 insertions(+), 28 deletions(-)

diff --git a/configure.ac b/configure.ac
index 32a80e01..8c32c92a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -67,27 +67,9 @@ AC_DEFUN([AC_LANG_CONFTEST(CPPAS)],
 $1
 _ACEOF])
 
-AC_CACHE_CHECK(
-  [whether the assembler is likely to work], [mdw_cv_gnuish_as],
-  [AC_LANG_PUSH([CPPAS])
-   AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
-	.text
-	.L\$_test = 23
-.macro	mymac
-	.L\$_test = .L\$_test + 1
-.endm
-	.globl	foo
-	.extern	bar
-	mymac]])],
-     [mdw_cv_gnuish_as=yes], [mdw_cv_gnuish_as=no])
-   AC_LANG_POP([CPPAS])])
-AM_CONDITIONAL([GNUISH_AS], [test $mdw_cv_gnuish_as = yes])
-
 dnl--------------------------------------------------------------------------
 dnl Host-specific configuration.
 
-AC_MSG_CHECKING([CPU family and ABI])
-
 dnl The table of CPU families and ABIs which we might support.  Support is
 dnl not uniform: each dispatched function might or might not have an
 dnl implementation for any particular CPU/ABI combination.
@@ -108,17 +90,32 @@ m4_ifdef([catacomb_seen_abi/$3],
 	  [m4_undefine([catacomb_seen_abi/$3])])])
 
 dnl Identify the current host.
-if test $mdw_cv_gnuish_as = no; then
-  CPUFAM=nil ABI=nil
-else
-  case $host_cpu,$host_os in
-    m4_define([catacomb_CPU_CASE],
-      [$1) CPUFAM=$2 ABI=$3 ;;
+case $host_cpu,$host_os in
+  m4_define([catacomb_CPU_CASE],
+    [$1) CPUFAM=$2 ABI=$3 ;;
 ])
-    catacomb_CPU_FAMILIES([catacomb_CPU_CASE])
-    *) CPUFAM=nil ABI=nil ;;
-  esac
-fi
+  catacomb_CPU_FAMILIES([catacomb_CPU_CASE])
+  *) CPUFAM=nil ABI=nil ;;
+esac
+
+dnl Now check the assembler.  We may have target-specific requirements here,
+dnl so we couldn't do this any earlier.
+AC_CACHE_CHECK(
+  [whether the assembler is likely to work], [mdw_cv_gnuish_as],
+  [AC_LANG_PUSH([CPPAS])
+   AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+	.text
+	.L\$_test = 23
+.macro	mymac
+	.L\$_test = .L\$_test + 1
+.endm
+	.globl	foo
+	.extern	bar
+	mymac]])],
+     [mdw_cv_gnuish_as=yes], [mdw_cv_gnuish_as=no])
+   AC_LANG_POP([CPPAS])])
+AM_CONDITIONAL([GNUISH_AS], [test $mdw_cv_gnuish_as = yes])
+if test $mdw_cv_gnuish_as = no; then CPUFAM=nil ABI=nil; fi
 
 dnl A hairy macro used to set the `CPUFAM_...' and `ABI_...' variables.  We
 dnl basically need to do the same thing for the family and ABI, so it's worth
@@ -135,6 +132,9 @@ m4_define([catacomb_DEFINE_CPU_OR_ABI],
   *) AC_MSG_ERROR([BUG: unexpected $1 \`$1']) ;;
 esac])
 
+dnl Now that's out the way, we can explain what we're doing.
+AC_MSG_CHECKING([CPU family and ABI])
+
 dnl Figure out the target CPU family and ABI.
 catacomb_CPU_FAMILIES([catacomb_CLEAR_FLAGS])
 catacomb_DEFINE_CPU_OR_ABI([CPUFAM], [2], [cpu],
-- 
[mdw]