ios - 将la脚的mp3编码器链接到iOS应用时，如何解决“ undefined symbol init_xrpow_core_sse”？

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

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，将生成的libmp3lame.a添加到Xcode 5.0.2中的iPhone项目中。为iOS设备构建时，它可以正常工作。构建模拟器时，我的问题开始了。这样做时，出现以下链接器错误:

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)

为什么会发生此错误，以及如何解决？

这是来自me脚库的quantize.c的代码片段:

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
}

最佳答案

问题出在--host的configure参数中。需要根据要在其上运行Simulator的计算机进行更改。就我而言，这是2009年中的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

因此，我疯狂地猜测，在运行模拟器的环境下，--host的configure参数需要设置为i686-apple-darwin12.5.0。猜测是正确的。现在，我的构建脚本如下所示:

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

在Xcode中为Simulator进行构建时，此方法有效。