Changeset d9bec1e for chapter06/gcc-pass2.xml

Timestamp:

03/17/2022 02:28:37 PM (2 years ago)

Author:

Thomas Trepl (Moody) <thomas@…>

Branches:

multilib

Children:

02c702c

Parents:

5ffa04b (diff), cc2c231 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Automatic merge of trunk into multilib

File:

• chapter06/gcc-pass2.xml (modified) (6 diffs)

chapter06/gcc-pass2.xml

@@ -65 +65 @@
 esac</userinput></screen>
 
-    <para arch="ml_32,ml_x32,ml_all">Change the default directory name for
+    <para arch="ml_32,ml_x32,ml_all">Change the default directory name for the
     libraries:</para>
 
@@ -71 +71 @@
     -e '/m32=/s/m32=.*/m32=..\/lib32$(call if_multiarch,:i386-linux-gnu)/' \
     -i.orig gcc/config/i386/t-linux64</userinput></screen>
-<!--
-<screen><userinput remap="pre">patch -Np1 -i ../&gcc-cross-patch;</userinput></screen>
--->
+
+    <!-- https://gcc.gnu.org/PR100017 -->
+    <para>Fix an issue causing failure cross-compiling libstdc++:</para>
+
+<screen><userinput remap="pre">sed 's/gnu++17/&amp; -nostdinc++/' \
+    -i libstdc++-v3/src/c++17/Makefile.in</userinput></screen>
+
+    <para>Override the building rule of libgcc and libstdc++ headers, to
+    allow building these libraries with POSIX threads support:</para>
+
+<screen><userinput remap="pre">sed '/thread_header =/s/@.*@/gthr-posix.h/' \
+    -i libgcc/Makefile.in libstdc++-v3/include/Makefile.in</userinput></screen>
+
     <para>Create a separate build directory again:</para>
 
 <screen><userinput remap="pre">mkdir -v build
 cd       build</userinput></screen>
-
-    <para>Create a symlink that allows libgcc to be built with posix threads
-    support:</para>
-
-<screen><userinput remap="pre">mkdir -pv $LFS_TGT/libgcc
-ln -s ../../../libgcc/gthr-posix.h $LFS_TGT/libgcc/gthr-default.h</userinput></screen>
 
     <para>Before starting to build GCC, remember to unset any environment
@@ -93 +97 @@
     --build=$(../config.guess)                     \
     --host=$LFS_TGT                                \
+    --target=$LFS_TGT                              \
+    LDFLAGS_FOR_TARGET=-L$PWD/$LFS_TGT/libgcc      \
     --prefix=/usr                                  \
-    CC_FOR_TARGET=$LFS_TGT-gcc                     \
     --with-build-sysroot=$LFS                      \
     --enable-initfini-array                        \
@@ -105 +110 @@
     --disable-libssp                               \
     --disable-libvtv                               \
-    --disable-libstdcxx                            \
     --enable-languages=c,c++</userinput></screen>
 <screen arch="ml_32,ml_x32,ml_all"><userinput remap="configure" 
@@ -133 +137 @@
 
       <varlistentry>
-        <term><parameter>-with-build-sysroot=$LFS</parameter></term>
+        <term><parameter>--with-build-sysroot=$LFS</parameter></term>
         <listitem>
           <para>Normally, using <parameter>--host</parameter> ensures that
@@ -146 +150 @@
 
       <varlistentry>
+        <term><parameter>--target=$LFS_TGT</parameter></term>
+        <listitem>
+          <para>As we are cross-compiling GCC, it's impossible to build
+          target libraries (<filename class="libraryfile">libgcc</filename>
+          and <filename class="libraryfile">libstdc++</filename>) with the
+          compiled GCC binaries because these binaries won't run on the
+          host distro.  GCC building system will attempt to use the
+          C and C++ compilers on the host distro as a workaround by default.
+          It's not supported to build GCC target libraries with a different
+          version of GCC, so using host compilers may cause building
+          failure.  This parameter ensures to build the libraries with GCC
+          pass 1 and prevent the issue.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><parameter>LDFLAGS_FOR_TARGET=...</parameter></term>
+        <listitem>
+          <para>Allow <filename class="libraryfile">libstdc++</filename> to
+          use shared <filename class="libraryfile">libgcc</filename> being
+          built in this pass, instead of the static version built in GCC
+          pass 1. This is needed for supporting C++ exception
+          handling.</para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
         <term><parameter>--enable-initfini-array</parameter></term>
         <listitem>