No rule to make target i686-unknown-linux-gnu/rt/arch/i386/morestack.o

[tomaka]

While compiling rust with Ubuntu 14.04 on a 32 bits machine with the --llvm-root flag:

...
extracting rust-stage0/bin/rustc
make: *** No rule to make target `i686-unknown-linux-gnu/rt/arch/i386/morestack.o', needed by `i686-unknown-linux-gnu/rt/libmorestack.a'.  Stop.

Removing --llvm-root fixes the problem, but I wanted to use the --llvm-root flag in order to use LLVM 3.3, which is the version required by emscripten.

(similar to #15228)

[nodakai]

@tomaka My understanding is, if we were able to build Rust with plain LLVM 3.x rather than rust-lang/llvm (a fork from LLVM SVN trunk,) the Rust developers would not have taken the trouble of maintaining the latter.

FYI, when I tried to build Rust Git HEAD with my installation of LLVM 3.4 a few weeks ago, the bootstraping stage aborted with an assert failure. Since then I just follow the standard build procedure.

[tomaka]

The Travis test uses a regular LLVM as well: https://github.com/rust-lang/rust/blob/master/.travis.yml

I'm not sure but I think that my issues simply comes from an inconsistency between i686 and i386. Travis runs on x86_64, that's why it's working fine.

[tomaka]

Removing these two lines fixed it:

• rust/mk/rt.mk

  Line 90 in 6f34760

  $$(LLVM_CONFIG_$$(CFG_BUILD))

• rust/mk/rt.mk

  Line 75 in 6f34760

  $$(LLVM_CONFIG_$$(CFG_BUILD))

I still don't know what the root of the problem is, though.

[steveklabnik]

Is this still a problem today?

[tomaka]

I'm probably never going to try this ever again.