将lame mp3编码器链接到iOS应用程序时如何解决“未定义符号init_xrpow_core_sse”？答案

【问题标题】：How to solve "Undefined symbol init_xrpow_core_sse" when linking lame mp3 encoder into iOS app?将lame mp3编码器链接到iOS应用程序时如何解决“未定义符号init_xrpow_core_sse”？
【发布时间】：2014-01-21 10:51:21
【问题描述】：

基于How can I compile lame as static library...?，我在 macbook pro 上使用此脚本编译了 lame：

mkdir -p build
rm -rf build/* #*/


function build_lame()
{
    make distclean

    ./configure \
        CFLAGS="-isysroot /Applications/Xcode.app/Contents/Developer/Platforms/${SDK}.platform/Developer/SDKs/$SDK$SDK_VERSION.sdk" \
        CC="/Applications/Xcode.app/Contents/Developer/usr/bin/gcc -arch $PLATFORM -miphoneos-version-min=7.0" \
        --prefix="/Users/$USER/Desktop/$PROJECTNAME" \
        --host="arm-apple-darwin9" \
        --disable-shared \
        --enable-static \
        --disable-frontend \

    make
    cp "$PROJECTNAME/.libs/$PROJECTNAME.a" "build/$PROJECTNAME-$PLATFORM.a"
}


PROJECTNAME=libmp3lame
SDK_VERSION=7.0


SDK="iPhoneSimulator"
PLATFORM="i386"
build_lame

SDK="iPhoneOS"
PLATFORM="armv7"
build_lame

SDK="iPhoneOS"
PLATFORM="armv7s"
build_lame


lipo -create build/$PROJECTNAME-* -output build/$PROJECTNAME.a

然后，我将生成的 libmp3lame.a 添加到 Xcode 5.0.2 中的 iPhone 项目中。在为 iOS 设备构建时，它工作正常。我的问题从为模拟器构建时开始。执行此操作时，我收到以下链接器错误：

Undefined symbols for architecture i386:
  "_init_xrpow_core_sse", referenced from:
      _init_xrpow_core_init in libmp3lame.a(quantize.o)
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

为什么会出现这个错误以及如何解决？

这是来自 lame 库的quantize.c 的代码 sn-p：

static void
init_xrpow_core_c(gr_info * const cod_info, FLOAT xrpow[576], int upper, FLOAT * sum)
{
    // here, the initialization of xrpow is done in normal c code (i've cut that out to keep it small)
}

void
init_xrpow_core_init(lame_internal_flags * const gfc)
{
    gfc->init_xrpow_core = init_xrpow_core_c;

#if defined(HAVE_XMMINTRIN_H)
    if (gfc->CPU_features.SSE)
        gfc->init_xrpow_core = init_xrpow_core_sse;
#endif
#ifndef HAVE_NASM
#ifdef MIN_ARCH_SSE
    gfc->init_xrpow_core = init_xrpow_core_sse;
#endif
#endif
}

【问题讨论】：

标签： ios iphone xcode lame i386

【解决方案1】：

问题出在configure 的--host 参数中。它需要根据您要运行模拟器的机器进行更改。就我而言，这是 2009 年中期的 MacBook Pro，运行 Mac OS X 10.8.5。

uname -a 报告：

Darwin <my computer name>.local 12.5.0 Darwin Kernel Version 12.5.0: Sun Sep 29 13:33:47 PDT 2013; root:xnu-2050.48.12~1/RELEASE_X86_64 x86_64

所以我猜想configure 的--host 参数需要设置为i686-apple-darwin12.5.0。猜测是对的。我的构建脚本现在看起来像这样：

mkdir -p build
rm -rf build/* #*/


function build_lame()
{
    make distclean

    ./configure \
        CFLAGS="-isysroot /Applications/Xcode.app/Contents/Developer/Platforms/${SDK}.platform/Developer/SDKs/$SDK$SDK_VERSION.sdk" \
        CC="/Applications/Xcode.app/Contents/Developer/usr/bin/gcc -arch $PLATFORM -miphoneos-version-min=7.0" \
        --prefix="/Users/$USER/Desktop/$PROJECTNAME" \
        --host="$HOST" \
        --disable-shared \
        --enable-static \
        --disable-frontend \

    make
    cp "$PROJECTNAME/.libs/$PROJECTNAME.a" "build/$PROJECTNAME-$PLATFORM.a"
}


PROJECTNAME=libmp3lame
SDK_VERSION=7.0


SDK="iPhoneSimulator"
HOST="i686-apple-darwin12.5.0"
PLATFORM="i686"
build_lame

SDK="iPhoneOS"
HOST="arm-apple-darwin9"
PLATFORM="armv7"
build_lame

SDK="iPhoneOS"
HOST="arm-apple-darwin9"
PLATFORM="armv7s"
build_lame


lipo -create build/$PROJECTNAME-* -output build/$PROJECTNAME.a

这在 Xcode 中为模拟器构建时有效。

【讨论】：