Android ndk-build 源碼分析

一、可以利用如下命令

bash -x ndk-build根據調試資訊來分析

二、

PROGDIR=`dirname $0`PROGDIR=`cd $PROGDIR && pwd`# Check if absolute NDK path contain space#case $PROGDIR in    *\ *) echo "ERROR: NDK path cannot contain space"          exit 1        ;;esac# If NDK_LOG is set to 1 or true in the environment, or the command-line# then enable log messages below# Also normalize NDK_HOST_32BIT and NDK_ANALYZE to 1 or 0if [ -z "$NDK_LOG" ]; then  NDK_LOG=0fiif [ -z "$NDK_HOST_32BIT" ]; then  NDK_HOST_32BIT=0fiif [ -z "$NDK_ANALYZE" ]; then  NDK_ANALYZE=0fi

PROGDIR為/home/jltxgcy/android-ndk-r8e

然後檢查這個目錄是否有空格

如果下面的變數長度為0，則都賦值為0

PROJECT_PATH=PROJECT_PATH_NEXT=for opt; do    if [ -z "$PROJECT_PATH" -a "$PROJECT_PATH_NEXT" = "yes" ] ; then        PROJECT_PATH=$opt        PROJECT_PATH_NEXT=    else        case $opt in          NDK_LOG=1|NDK_LOG=true)            NDK_LOG=1            ;;          NDK_LOG=*)            NDK_LOG=0            ;;          NDK_HOST_32BIT=1|NDK_HOST_32BIT=true)            NDK_HOST_32BIT=1            ;;          NDK_HOST_32BIT=*)            NDK_HOST_32BIT=0            ;;          NDK_ANALYZE=1|NDK_ANALYZE=true)            NDK_ANALYZE=1            ;;          NDK_ANALYZE=*)            NDK_ANALYZE=0            ;;          NDK_TOOLCHAIN_VERSION=*)            NDK_TOOLCHAIN_VERSION=${opt#NDK_TOOLCHAIN_VERSION=}            ;;          APP_ABI=*)            APP_ABI=${opt#APP_ABI=}            ;;          -C)            PROJECT_PATH_NEXT="yes"            ;;        esac    fidone

此段代碼沒有執行，暫不分析

if [ "$NDK_LOG" = "true" ]; then  NDK_LOG=1fiif [ "$NDK_HOST_32BIT" = "true" ]; then  NDK_HOST_32BIT=1fiif [ "$NDK_ANALYZE" = "true" ]; then  NDK_ANALYZE=1fiif [ "$NDK_LOG" = "1" ]; then  log () {    echo "$@"  }else  log () {    : # nothing  }fi

此段代碼均為假，不執行

# Detect host operating system and architecture# The 64-bit / 32-bit distinction gets tricky on Linux and Darwin because# uname -m returns the kernel's bit size, and it's possible to run with# a 64-bit kernel and a 32-bit userland.#HOST_OS=$(uname -s)case $HOST_OS in  Darwin) HOST_OS=darwin;;  Linux) HOST_OS=linux;;  FreeBsd) HOST_OS=freebsd;;  CYGWIN*|*_NT-*) HOST_OS=cygwin;;  *) echo "ERROR: Unknown host operating system: $HOST_OS"     exit 1esaclog "HOST_OS=$HOST_OS"

HOST_OS為Linux，所以HOST_OS為linux

HOST_ARCH=$(uname -m)case $HOST_ARCH in    i?86) HOST_ARCH=x86;;    x86_64|amd64) HOST_ARCH=x86_64;;    *) echo "ERROR: Unknown host CPU architecture: $HOST_ARCH"       exit 1esaclog "HOST_ARCH=$HOST_ARCH"

HOST_ARCH為x86_64

# Detect 32-bit userland on 64-bit kernelsHOST_TAG="$HOST_OS-$HOST_ARCH"case $HOST_TAG in  linux-x86_64|darwin-x86_64)    # we look for x86_64 or x86-64 in the output of 'file' for our shell    # the -L flag is used to dereference symlinks, just in case.    file -L "$SHELL" | grep -q "x86[_-]64"    if [ $? != 0 ]; then      HOST_ARCH=x86      log "HOST_ARCH=$HOST_ARCH (32-bit userland detected)"    fi    ;;esac

檢查file -L "$SHELL" | grep -q "x86[_-]64"是否正確，如果不正確，那麼HOST_ARCH為x86

# Check that we have 64-bit binaries on 64-bit system, otherwise fallback# on 32-bit ones. This gives us more freedom in packaging the NDK.LOG_MESSAGE=if [ $HOST_ARCH = x86_64 ]; then  if [ ! -d $PROGDIR/prebuilt/$HOST_TAG ]; then    HOST_ARCH=x86    LOG_MESSAGE="(no 64-bit prebuilt binaries detected)"  fi  if [ "$NDK_HOST_32BIT" = "1" ]; then    HOST_ARCH=x86    LOG_MESSAGE="(force 32-bit host toolchain)"  fifi

如果/home/jltxgcy/android-ndk-r8e/prebuilt/linux-x86_64不存在，那麼HOST_ARCH為x86

# If GNUMAKE is defined, check that it points to a valid fileif [ -n "$GNUMAKE" ] ; then    ABS_GNUMAKE=`which $GNUMAKE 2> /dev/null`    if [ $? != 0 ] ; then        echo "ERROR: Your GNUMAKE variable is defined to an invalid name: $GNUMAKE"        echo "Please fix it to point to a valid make executable (e.g. /usr/bin/make)"        exit 1    fi    GNUMAKE="$ABS_GNUMAKE"    log "GNUMAKE=$GNUMAKE (from environment variable)"else    # Otherwise use the prebuilt version for our host tag, if it exists    # Note: we intentionally do not provide prebuilt make binaries for Cygwin    # or MSys.    GNUMAKE=$PROGDIR/prebuilt/$HOST_TAG/bin/make    if [ ! -f "$GNUMAKE" ]; then        # Otherwise, use 'make' and check that it is available        GNUMAKE=`which make 2> /dev/null`        if [ $? != 0 ] ; then            echo "ERROR: Cannot find 'make' program. Please install Cygwin make package"            echo "or define the GNUMAKE variable to point to it."            exit 1        fi        log "GNUMAKE=$GNUMAKE (system path)"    else        log "GNUMAKE=$GNUMAKE (NDK prebuilt)"    fifi

GNUMAKE長度為0，進入else，/home/jltxgcy/android-ndk-r8e/prebuilt/linux-x86_64/bin/make是否存在，如果存在，GNUMAKE就是它了。如果不存在，利用which make尋找系統的make。

# On Windows, when running under cygwin, check that we are# invoking a cygwin-compatible GNU Make binary. It is unfortunately# common for app developers to have another non cygwin-compatible# 'make' program in their PATH.#if [ "$OSTYPE" = "cygwin" ] ; then    GNUMAKE=`cygpath -u $GNUMAKE`    PROGDIR_MIXED=`cygpath -m $PROGDIR`    CYGWIN_GNUMAKE=`$GNUMAKE -f "$PROGDIR_MIXED/build/core/check-cygwin-make.mk" 2>&1`    if [ $? != 0 ] ; then        echo "ERROR: You are using a non-Cygwin compatible Make program."        echo "Currently using: `cygpath -m $GNUMAKE`"        echo ""        echo "To solve the issue, follow these steps:"        echo ""        echo "1. Ensure that the Cygwin 'make' package is installed."        echo "   NOTE: You will need GNU Make 3.81 or later!"        echo ""        echo "2. Define the GNUMAKE environment variable to point to it, as in:"        echo ""        echo "     export GNUMAKE=/usr/bin/make"        echo ""        echo "3. Call 'ndk-build' again."        echo ""        exit 1    fi    log "Cygwin-compatible GNU make detected"fiif [ "$NDK_ANALYZE" = 1 ]; then    . $PROGDIR/build/tools/dev-defaults.sh  # for DEFAULT_LLVM_VERSION    # Find perl.  If HOST_PERL is defined, check that it points to a valid file    HOST_PERL_LIB=    if [ -n "$HOST_PERL" ] ; then        ABS_PERL=`which $HOST_PERL 2> /dev/null`        if [ $? != 0 ] ; then            echo "ERROR: Your HOST_PERL variable is defined to an invalid name: $HOST_PERL"            echo "Please fix it to point to a valid perl executable (e.g. /usr/bin/perl)"            exit 1        fi        HOST_PERL="$ABS_PERL"        log "HOST_PERL=$HOST_PERL (from environment variable)"    else        # Otherwise use the prebuilt version for our host tag        HOST_PERL="$PROGDIR/prebuilt/$HOST_TAG/bin/perl"        if [ ! -f "$HOST_PERL" ]; then            # Otherwise, use 'perl' and check that it is available            HOST_PERL=`which perl 2> /dev/null`            if [ $? != 0 ] ; then                echo "ERROR: Cannot find 'perl' program. Please install perl package"                echo "or define the HOST_PERL variable to point to it."                exit 1            fi            log "HOST_PERL=$HOST_PERL (system path)"        else            HOST_PERL_LIB="$PROGDIR/prebuilt/$HOST_TAG/lib/perl5"            log "HOST_PERL=$HOST_PERL (NDK prebuilt)"        fi    fi    # Return flags send in env. or command line which are enough to retrive APP_ABI and TOOLCHAIN_PREFIX later    gen_flags ()    {        local FLAGS=        if [ -n "$PROJECT_PATH" ] ; then            FLAGS=$FLAGS" -C $PROJECT_PATH"        fi        if [ -n "$APP_ABI" ] ; then            FLAGS=$FLAGS" APP_ABI=$APP_ABI"        fi        if [ -n "$NDK_HOST_32BIT" ] ; then            FLAGS=$FLAGS" NDK_HOST_32BIT=$NDK_HOST_32BIT"        fi        if [ -n "$NDK_TOOLCHAIN_VERSION" ] ; then            FLAGS=$FLAGS" NDK_TOOLCHAIN_VERSION=$NDK_TOOLCHAIN_VERSION"        fi        echo "$FLAGS"    }    get_build_var ()    {        local VAR=$1        local FLAGS=`gen_flags`        $GNUMAKE --no-print-dir -f $PROGDIR/build/core/build-local.mk $FLAGS DUMP_${VAR} | tail -1    }    get_build_var_for_abi ()    {        local VAR=$1        local ABI=$2        local FLAGS=`gen_flags`        $GNUMAKE --no-print-dir -f $PROGDIR/build/core/build-local.mk $FLAGS DUMP_${VAR} APP_ABI=${ABI} | tail -1    }    APP_ABIS=`get_build_var APP_ABI`    for ABI in $APP_ABIS; do        TOOLCHAIN_PREFIX=`get_build_var_for_abi TOOLCHAIN_PREFIX $ABI`        PERL5LIB="$HOST_PERL_LIB" "$HOST_PERL" $PROGDIR/prebuilt/common/scan-build/scan-build \            --use-analyzer $PROGDIR/toolchains/llvm-${DEFAULT_LLVM_VERSION}/prebuilt/$HOST_TAG/bin/${ABI}/analyzer \            --use-cc ${TOOLCHAIN_PREFIX}gcc \            --use-c++ ${TOOLCHAIN_PREFIX}g++ \            --status-bugs -v -v \            $GNUMAKE -f $PROGDIR/build/core/build-local.mk "$@" APP_ABI=$ABI    doneelse    $GNUMAKE -f $PROGDIR/build/core/build-local.mk "$@"fi

此段代碼只執行最後一句，/home/jltxgcy/android-ndk-r8e/prebuilt/linux-x86_64/bin/make /home/jltxgcy/android-ndk-r8e/build/core/build-local.mk