[Bug libstdc++/35942] Self Reference In Dynamic Linked Library builds for building Cross-Compiler

[earthengine at gmail dot com]

------- Comment #8 from earthengine at gmail dot com  2008-10-22 10:53 -------
Let me explain it more clearly.

Suppose I am building a toolchain to be running on a x86 Linux machine, and it
will generate code for mips Linux. With gcc 4.2.x, I can use

--host=i686-pc-linux-gnu --target=mips-linux-gnu

and it will work on both x86-64 marchines as well because the 4.2.x build
system will use i686-pc-linux-gnu as the --build parameter, and then it will be
a case of normal cross compile.

However, the previous configuration does not work under 4.3+. The reason is
under 4.3+ the build system will detect the --build parameter as well, so the
configuration will become

--build=x86_64-unknown-linux-gnu --host=i686-pc-linux-gnu
--target=mips-linux-gnu

This is a Canadian cross compile! Usually, to complete a Canadian cross
compile, we need the libstdc++ for mips-linux-gnu already because it can not
depending on the just-compiled compiler (it would not run on the build machine)
to compile this library.

This is why we have this problem. The solution is to explicitly use

--build=i686-pc-linux-gnu --host-pc-linux-gnu --target=mips-linux-gnu

to force a normal cross compile.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35942