From 7be093ea4d50c8d38438f88cb9fa817c1c9de8dd Mon Sep 17 00:00:00 2001
From: Jan Kratochvil <jan.kratochvil@redhat.com>
Date: Tue, 5 Oct 2010 19:15:08 +0200
Subject: [PATCH] nasm: add configure support

yasm has to be preferred as currently nasm produces marginally less
efficient code (longer opcodes). Filed for nasm as:
https://sourceforge.net/tracker/?func=detail&atid=106208&aid=3037462&group_id=6208

OTOH package should be built always the same, no matter which additional
packages are / are not present on the system. As the package should be
built with nasm (as yasm may not be available) we should not use yasm
even if it is possibly available.

nasm >= approx. 2.09 is required for the nasm compilation as the former
versions had a section alignment bug.

Provide nasm compatibility. No binary change by this patch with yasm on
{x86_64,i686}-fedora13-linux-gnu. Few longer opcodes with nasm on
{x86_64,i686}-fedora13-linux-gnu have been checked as safe.

Change-Id: Icb0fe39c64bbcc3bcd7972e392fd03f3273340df
---
 build/make/configure.sh | 43 ++++++++++++++++++++++++++++++++++++-----
 configure               |  2 ++
 2 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/build/make/configure.sh b/build/make/configure.sh
index cfac5391c..e20f0d133 100755
--- a/build/make/configure.sh
+++ b/build/make/configure.sh
@@ -255,9 +255,10 @@ TMP_H="${TMPDIRx}/vpx-conf-$$-${RANDOM}.h"
 TMP_C="${TMPDIRx}/vpx-conf-$$-${RANDOM}.c"
 TMP_O="${TMPDIRx}/vpx-conf-$$-${RANDOM}.o"
 TMP_X="${TMPDIRx}/vpx-conf-$$-${RANDOM}.x"
+TMP_ASM="${TMPDIRx}/vpx-conf-$$-${RANDOM}.asm"
 
 clean_temp_files() {
-    rm -f ${TMP_C} ${TMP_H} ${TMP_O} ${TMP_X}
+    rm -f ${TMP_C} ${TMP_H} ${TMP_O} ${TMP_X} ${TMP_ASM}
 }
 
 #
@@ -322,6 +323,21 @@ check_add_ldflags() {
     add_ldflags "$@"
 }
 
+check_asm_align() {
+    log check_asm_align "$@"
+    cat >${TMP_ASM} <<EOF
+section .rodata
+align 16
+EOF
+    log_file ${TMP_ASM}
+    check_cmd ${AS} ${ASFLAGS} -o ${TMP_O} ${TMP_ASM}
+    readelf -WS ${TMP_O} >${TMP_X}
+    log_file ${TMP_X}
+    if ! grep -q '\.rodata .* 16$' ${TMP_X}; then
+        die "${AS} ${ASFLAGS} does not support section alignment (nasm <=2.08?)"
+    fi
+}
+
 write_common_config_banner() {
     echo '# This file automatically generated by configure. Do not edit!' > config.mk
     echo "TOOLCHAIN := ${toolchain}" >> config.mk
@@ -440,13 +456,18 @@ process_common_cmdline() {
         disable builtin_libc
         alt_libc="${optval}"
         ;;
+        --as=*)
+        [ "${optval}" = yasm -o "${optval}" = nasm -o "${optval}" = auto ] \
+            || die "Must be yasm, nasm or auto: ${optval}"
+        alt_as="${optval}"
+        ;;
         --prefix=*)
         prefix="${optval}"
         ;;
         --libdir=*)
         libdir="${optval}"
         ;;
-        --libc|--prefix|--libdir)
+        --libc|--as|--prefix|--libdir)
         die "Option ${opt} requires argument"
         ;;
         --help|-h) show_help
@@ -802,6 +823,7 @@ process_common_toolchain() {
                 ;;
         esac
 
+        AS="${alt_as:-${AS:-auto}}"
         case  ${tgt_cc} in
             icc*)
                 CC=${CC:-icc}
@@ -830,7 +852,16 @@ process_common_toolchain() {
                 ;;
         esac
 
-        AS=yasm
+        case "${AS}" in
+            auto|"")
+                which nasm >/dev/null 2>&1 && AS=nasm
+                which yasm >/dev/null 2>&1 && AS=yasm
+                [ "${AS}" = auto -o -z "${AS}" ] \
+                    && die "Neither yasm nor nasm have been found"
+                ;;
+        esac
+        log_echo "  using $AS"
+        [ "${AS##*/}" = nasm ] && add_asflags -Ox
         AS_SFX=.asm
         case  ${tgt_os} in
             win*)
@@ -839,7 +870,9 @@ process_common_toolchain() {
             ;;
             linux*|solaris*)
                 add_asflags -f elf${bits}
-                enabled debug && add_asflags -g dwarf2
+                enabled debug && [ "${AS}" = yasm ] && add_asflags -g dwarf2
+                enabled debug && [ "${AS}" = nasm ] && add_asflags -g
+                [ "${AS##*/}" = nasm ] && check_asm_align
             ;;
             darwin*)
                 add_asflags -f macho${bits}
@@ -852,7 +885,7 @@ process_common_toolchain() {
                 # enabled icc && ! enabled pic && add_cflags -fno-pic -mdynamic-no-pic
                 enabled icc && ! enabled pic && add_cflags -fno-pic
             ;;
-            *) log "Warning: Unknown os $tgt_os while setting up yasm flags"
+            *) log "Warning: Unknown os $tgt_os while setting up $AS flags"
             ;;
         esac
     ;;
diff --git a/configure b/configure
index b3cd0c72b..0321e1abf 100755
--- a/configure
+++ b/configure
@@ -23,6 +23,7 @@ Advanced options:
   ${toggle_libs}                  don't build libraries
   ${toggle_examples}              don't build examples
   --libc=PATH                     path to alternate libc
+  --as={yasm|nasm|auto}           use specified assembler [auto, yasm preferred]
   ${toggle_fast_unaligned}        don't use unaligned accesses, even when
                                   supported by hardware [auto]
   ${toggle_codec_srcs}            in/exclude codec library source code
@@ -266,6 +267,7 @@ CMDLINE_SELECT="
     libs
     examples
     libc
+    as
     fast_unaligned
     codec_srcs
     debug_libs
-- 
2.40.0