1*4882a593Smuzhiyun# 2*4882a593Smuzhiyun# Notes on the way the OE cross toolchain now works 3*4882a593Smuzhiyun# 4*4882a593Smuzhiyun# We need a libgcc to build glibc. Tranditionally we therefore built 5*4882a593Smuzhiyun# a non-threaded and non-shared compiler (gcc-cross-initial), then use 6*4882a593Smuzhiyun# that to build libgcc-initial which is used to build glibc which we can 7*4882a593Smuzhiyun# then build gcc-cross and libgcc against. 8*4882a593Smuzhiyun# 9*4882a593Smuzhiyun# We were able to drop the glibc dependency from gcc-cross, with two tweaks: 10*4882a593Smuzhiyun 11*4882a593Smuzhiyun# a) specify the minimum glibc version to support in a configure option 12*4882a593Smuzhiyun# b) create a dummy limits.h file so that later when glibc creates one, 13*4882a593Smuzhiyun# the headers structure has support for it. We can do this with a simple 14*4882a593Smuzhiyun# empty file 15*4882a593Smuzhiyun# 16*4882a593Smuzhiyun# Once gcc-cross is libc independent, we can use it to build both 17*4882a593Smuzhiyun# libgcc-initial and then later libgcc. 18*4882a593Smuzhiyun# 19*4882a593Smuzhiyun# libgcc-initial is tricky as we need to imitate the non-threaded and 20*4882a593Smuzhiyun# non-shared case. We can do that by hacking the threading mode back to 21*4882a593Smuzhiyun# "single" even if gcc reports "posix" and disable libc presence for the 22*4882a593Smuzhiyun# libgcc-intial build. We have to create the dummy limits.h to avoid 23*4882a593Smuzhiyun# compiler errors from a missing header. 24*4882a593Smuzhiyun# 25*4882a593Smuzhiyun# glibc will fail to link with libgcc-initial due to a missing "exception 26*4882a593Smuzhiyun# handler" capable libgcc (libgcc_eh.a). Since we know glibc doesn't need 27*4882a593Smuzhiyun# any exception handler, we can safely symlink to libgcc.a. 28*4882a593Smuzhiyun# 29*4882a593Smuzhiyun 30*4882a593Smuzhiyunrequire libgcc-common.inc 31*4882a593Smuzhiyun 32*4882a593SmuzhiyunDEPENDS = "virtual/${TARGET_PREFIX}gcc" 33*4882a593Smuzhiyun 34*4882a593SmuzhiyunLICENSE = "GPL-3.0-with-GCC-exception" 35*4882a593Smuzhiyun 36*4882a593SmuzhiyunPACKAGES = "" 37*4882a593Smuzhiyun 38*4882a593SmuzhiyunEXTRA_OECONF += "--disable-shared" 39*4882a593Smuzhiyun 40*4882a593Smuzhiyuninherit nopackages 41*4882a593Smuzhiyun 42*4882a593Smuzhiyun# We really only want this built by things that need it, not any recrdeptask 43*4882a593Smuzhiyundeltask do_build 44*4882a593Smuzhiyun 45*4882a593Smuzhiyundo_configure:prepend () { 46*4882a593Smuzhiyun install -d ${STAGING_INCDIR} 47*4882a593Smuzhiyun touch ${STAGING_INCDIR}/limits.h 48*4882a593Smuzhiyun sed -i -e 's#INHIBIT_LIBC_CFLAGS =.*#INHIBIT_LIBC_CFLAGS = -Dinhibit_libc#' ${B}/gcc/libgcc.mvars 49*4882a593Smuzhiyun sed -i -e 's#inhibit_libc = false#inhibit_libc = true#' ${B}/gcc/Makefile 50*4882a593Smuzhiyun} 51*4882a593Smuzhiyun 52*4882a593Smuzhiyundo_configure:append () { 53*4882a593Smuzhiyun sed -i -e 's#thread_header = .*#thread_header = gthr-single.h#' ${B}/${BPN}/Makefile 54*4882a593Smuzhiyun} 55*4882a593Smuzhiyun 56*4882a593Smuzhiyundo_install:append () { 57*4882a593Smuzhiyun ln -s libgcc.a ${D}${libdir}/${TARGET_SYS}/${BINV}/libgcc_eh.a 58*4882a593Smuzhiyun} 59