如何在任意系統上找到並測試編譯器正在使用的*實際鏈接器？

Question

我需要傳遞一些對象[some assembler |另一個編譯器|一個檔案]直接鏈接到鏈接器。

但似乎在路徑上找到的ld是[broken |缺少|鏈接錯誤的ABI]。
有時，我根本找不到ld。

無論C編譯器是什麼，我如何才能找到正在使用的實際鏈接器，
[在Mac上|在Linux上在BSD |上從配置腳本]？

Answer 1

我只是想出了這一個。
這是一種艱難，所以我想我會分享。

給這一個鏡頭：

#!/usr/bin/env sh 

# 'main;' is the shortest C program possible (I think.). 
# So it is compiled, linked, and written to /dev/null. 
# So if the linker can't link, this should return 1. 

for link in collect2 ld; do # Order matters, because of GCC. 
echo 'main;' | $CC -v -x c - -o /dev/null -\#\#\# 2>&1 | grep -q $link && 
echo 'main;' | $CC -v -x c - -o /dev/null -\#\#\# 2>&1 | grep $link | 
sed -e "s|\(.*$link\).*|\1|" -e 's/ //g' -e 's|"||' && break 
done 

# That should work on just about anything, and returns an absolute path, 
# except with ICC. If we want to try to get an absolute path there too, 
# we have to: 

# If 'which' is missing, and it might not have an -s flag. 
which="$(which which >/dev/null 2>&1)" || which=echo 

$which "$(for link in collect2 ld; do 
echo 'main;' | $CC -v -x c - -o /dev/null -\#\#\# 2>&1 | grep -q $link && 
echo 'main;' | $CC -v -x c - -o /dev/null -\#\#\# 2>&1 | grep $link | 
sed -e "s|\(.*$link\).*|\1|" -e 's/ //g' -e 's|"||' && break 
done)" 

所以，你可能剛纔所說的，

來吧傢伙，沒辦法這是必要的！就像，which ld。

誠實而真實地說，這對我來說在很大一部分時間裏並不適用。
今天不是很不尋常，因爲ld經常是一個包裝。

讓我們測試一下，看看有什麼變成了：

#!/usr/bin/env sh 

# On my Mac, nothing too special, I swear. 
# Just a MacBook, Xcode, GCC from Homebrew, and one commercial compiler. 


echo; $which ld; echo "...Not necessarily."; echo 

for CC in cc gcc clang icc; do echo $c: 
    for link in collect2 ld; do 
    echo 'main;' | $CC -v -x c - -o /dev/null -\#\#\# 2>&1 | grep -q $link && 
    echo 'main;' | $CC -v -x c - -o /dev/null -\#\#\# 2>&1 | grep $link | 
     sed -e "s|\(.*$link\).*|\1|" -e 's/ //g' -e 's|"||' && break 
    done 

    which="$(which which 2>/dev/null 1>&1)" || which=echo 
    $which "$(for link in collect2 ld; do 
    echo 'main;' | $CC -v -x c - -o /dev/null -\#\#\# 2>&1 | grep -q $link && 
    echo 'main;' | $CC -v -x c - -o /dev/null -\#\#\# 2>&1 | grep $link | 
    sed -e "s|\(.*$link\).*|\1|" -e 's/ //g' -e 's|"||' && break 
    done)" 
    echo 
done 

返回：

/usr/bin/ld 
...Not necessarily. 

cc: 
/Applications/Xcode51-Beta4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld 
/Applications/Xcode51-Beta4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld 

gcc: 
/Users/Shared/usr/local/Cellar/gcc49/4.9-20140119/libexec/gcc/x86_64-apple-darwin13.1.0/4.9.0/collect2 
/Users/Shared/usr/local/Cellar/gcc49/4.9-20140119/libexec/gcc/x86_64-apple-darwin13.1.0/4.9.0/collect2 

clang: 
/Applications/Xcode51-Beta4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld 
/Applications/Xcode51-Beta4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld 

icc: 
ld 
/usr/bin/ld