From 3bb463d33d713d262b4864d8d3c6af08e25c77aa Mon Sep 17 00:00:00 2001
From: Xi Ruoyao <xry111@mengyan1223.wang>
Date: Tue, 1 Mar 2022 18:09:30 +0800
Subject: gcc-pass2: document *_FOR_TARGET parameters

---
 chapter06/gcc-pass2.xml | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

(limited to 'chapter06')

diff --git a/chapter06/gcc-pass2.xml b/chapter06/gcc-pass2.xml
index d10b403e9..d76b9d9af 100644
--- a/chapter06/gcc-pass2.xml
+++ b/chapter06/gcc-pass2.xml
@@ -107,7 +107,7 @@ cd       build</userinput></screen>
       <title>The meaning of the new configure options:</title><!-- WIP -->
 
       <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
           a cross-compiler is used for building GCC, and that compiler knows
@@ -119,6 +119,33 @@ cd       build</userinput></screen>
         </listitem>
       </varlistentry>
 
+      <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>
-- 
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