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scripts/trylink: fix bit-rotted linker option verification

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To that end, *make it complain* when check_cc fails on options
we usually want to succeed.

   text	   data	    bss	    dec	    hex	filename
 929697	    932	  17692	 948321	  e7861	busybox-1.23.2/busybox
 915361	    911	  17484	 933756	  e3f7c	busybox-1.23.2.fixed/busybox

 927725	    932	  17448	 946105	  e6fb9	busybox-1.24.0/busybox
 913630	    911	  17240	 931781	  e37c5	busybox-1.24.0.fixed/busybox

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2015-10-20 16:16:16 +02:00
parent 76efb3ed33
commit 5134010d88
1 changed files with 35 additions and 24 deletions
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59
scripts/trylink
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@ -47,18 +47,22 @@ try() {
check_cc() { check_cc() {
local tempname="$(mktemp)" local tempname="$(mktemp)"
local r
echo "int main(int argc,char**argv){return argv?argc:0;}" >"$tempname".c
# Can use "-o /dev/null", but older gcc tend to *unlink it* on failure! :( # Can use "-o /dev/null", but older gcc tend to *unlink it* on failure! :(
# "-xc": C language. "/dev/null" is an empty source file. # Was using "-xc /dev/null", but we need a valid C program.
if $CC $CPPFLAGS $CFLAGS $1 -shared -xc /dev/null -o "$tempname".o >/dev/null 2>&1; then # "eval" is needed because CFLAGS can contain
echo "$1"; # '... -D"BB_VER=KBUILD_STR(1.N.M)" ...'
else # and we need shell to process quotes!
echo "$2"; eval $CC $CPPFLAGS $CFLAGS $1 "$tempname".c -o "$tempname" >/dev/null 2>&1
fi r=$?
rm -f "$tempname" "$tempname".o rm -f "$tempname" "$tempname".c "$tempname".o
return $r
} }
check_libc_is_glibc() { check_libc_is_glibc() {
local tempname="$(mktemp)" local tempname="$(mktemp)"
local r
echo "\ echo "\
#include <stdlib.h> #include <stdlib.h>
/* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */ /* Apparently uclibc defines __GLIBC__ (compat trick?). Oh well. */
@ -66,12 +70,10 @@ check_libc_is_glibc() {
syntax error here syntax error here
#endif #endif
" >"$tempname".c " >"$tempname".c
if $CC $CPPFLAGS $CFLAGS "$tempname".c -c -o "$tempname".o >/dev/null 2>&1; then $CC $CPPFLAGS $CFLAGS "$tempname".c -c -o "$tempname".o >/dev/null 2>&1
echo "$2"; r=$?
else rm -f "$tempname" "$tempname".c "$tempname".o
echo "$1"; return $r
fi
rm -f "$tempname" "$tempname".[co]
} }
EXE="$1" EXE="$1"
@ -83,32 +85,41 @@ A_FILES="$6"
LDLIBS="$7" LDLIBS="$7"
# The --sort-section option is not supported by older versions of ld # The --sort-section option is not supported by older versions of ld
SORT_SECTION=`check_cc "-Wl,--sort-section,alignment" ""` SORT_SECTION="-Wl,--sort-section,alignment"
if ! check_cc "-Wl,--sort-section,alignment"; then
echo "Your linker does not support --sort-section,alignment"
SORT_SECTION=""
fi
START_GROUP="-Wl,--start-group" START_GROUP="-Wl,--start-group"
END_GROUP="-Wl,--end-group" END_GROUP="-Wl,--end-group"
INFO_OPTS="-Wl,--warn-common -Wl,-Map,$EXE.map -Wl,--verbose" INFO_OPTS="-Wl,--warn-common -Wl,-Map,$EXE.map -Wl,--verbose"
# gold may not support --sort-common (yet) # gold may not support --sort-common (yet)
SORT_COMMON=`check_cc "-Wl,--sort-common" ""` SORT_COMMON="-Wl,--sort-common"
if ! check_cc "-Wl,--sort-common"; then
echo "Your linker does not support --sort-common"
SORT_COMMON=""
fi
# Static linking against glibc produces buggy executables # Static linking against glibc produces buggy executables
# (glibc does not cope well with ld --gc-sections). # (glibc does not cope well with ld --gc-sections).
# See sources.redhat.com/bugzilla/show_bug.cgi?id=3400 # See sources.redhat.com/bugzilla/show_bug.cgi?id=3400
# Note that glibc is unsuitable for static linking anyway. # Note that glibc is unsuitable for static linking anyway.
# We are removing -Wl,--gc-sections from link command line. # We are removing -Wl,--gc-sections from link command line.
GC_SECTIONS=`( GC_SECTIONS="-Wl,--gc-sections"
. ./.config if (. ./.config && test x"$CONFIG_STATIC" = x"y") then
if test x"$CONFIG_STATIC" = x"y"; then if check_libc_is_glibc; then
check_libc_is_glibc "" "-Wl,--gc-sections" echo "Static linking against glibc, can't use --gc-sections"
else GC_SECTIONS=""
echo "-Wl,--gc-sections" fi
fi fi
)`
# The --gc-sections option is not supported by older versions of ld # The --gc-sections option is not supported by older versions of ld
if test -n "$GC_SECTIONS"; then if test -n "$GC_SECTIONS"; then
GC_SECTIONS=`check_cc "$GC_SECTIONS" ""` if ! check_cc "$GC_SECTIONS"; then
echo "Your linker does not support $GC_SECTIONS"
GC_SECTIONS=""
fi
fi fi
# Sanitize lib list (dups, extra spaces etc) # Sanitize lib list (dups, extra spaces etc)