From: Mark Wooding <mdw@distorted.org.uk>
Date: Wed, 5 Jul 2017 21:09:59 +0000 (+0100)
Subject: configure.ac: Check for some brain damage from Clang's assembler.
X-Git-Tag: 2.4.2~40
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/catacomb/commitdiff_plain/8ed49b833de82dd5f8cf4c010a37cf8d2dc0e4ea

configure.ac: Check for some brain damage from Clang's assembler.

It doesn't understand `.arch' or the `adcd' instruction.  I'm damned if
I'm writing `dword ptr' everywhere, so Clang users will have to figure
out some way to use Gas if they want the assembler code.
---

diff --git a/configure.ac b/configure.ac
index 8c32c92a..bdc94be7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -98,8 +98,8 @@ case $host_cpu,$host_os in
   *) 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.
+dnl Now check the assembler.  We have target-specific requirements here, so
+dnl 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])
@@ -113,6 +113,22 @@ AC_CACHE_CHECK(
 	.extern	bar
 	mymac]])],
      [mdw_cv_gnuish_as=yes], [mdw_cv_gnuish_as=no])
+   case $CPUFAM in
+     x86 | amd64)
+       AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+	.text
+	.arch pentium4
+	.intel_syntax noprefix
+	.globl	foo
+foo:
+	adcd	var, 0
+	ret
+	.data
+var:	.long	1
+	]])],
+	 [:], [mdw_cv_gnuish_as=no])
+       ;;
+   esac
    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