Cannot compile rustc on FreeBSD

[aidancully]

Problem was introduced in 95d9046.

Command line:

CFG_LLVM_LINKAGE_FILE=/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/rt/llvmdeps.rs \
LD_LIBRARY_PATH=/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib:$LD_LIBRARY_PATH   \
x86_64-unknown-freebsd/stage1/bin/rustc --cfg stage1  -O --cfg rtopt --cfg debug \
-C prefer-dynamic --target=x86_64-unknown-freebsd  -D warnings \
-L "x86_64-unknown-freebsd/rt" \
-L "/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/llvm/Release+Asserts/lib" \
-L ""  \
--out-dir x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib \
-C extra-filename=-4e7c5e5c /usr/home/aidan/rust/rust/src/libstd/lib.rs

Produces error:

error: linking with `cc` failed: exit code: 1
note: "cc" "-L/usr/local/lib" "-L/usr/local/lib/gcc46" "-L/usr/local/lib/gcc44" "-m64" \
"-L" "/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib" \
"-o" "x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/libstd-4e7c5e5c.so" \
"x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/std-4e7c5e5c.o" \
"-Wl,--whole-archive" "-lmorestack" "-Wl,--no-whole-archive" \
"x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/std-4e7c5e5c.metadata.o" \
"-nodefaultlibs" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/libcollections-4e7c5e5c.rlib" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/librand-4e7c5e5c.rlib" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/liballoc-4e7c5e5c.rlib" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/libunicode-4e7c5e5c.rlib" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/liblibc-4e7c5e5c.rlib" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/libcore-4e7c5e5c.rlib" \
"-L" "x86_64-unknown-freebsd/rt" \
"-L" "/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/llvm/Release+Asserts/lib" \
"-L" "" \
"-L" "/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib" \
"-L" "/usr/home/aidan/rust/rust/.rust/lib/x86_64-unknown-freebsd" \
"-L" "/usr/home/aidan/rust/rust/lib/x86_64-unknown-freebsd" \
"-Wl,--whole-archive" "-Wl,-Bstatic" "-lrust_builtin" "-lbacktrace" "-lrustrt_native" \
"-Wl,--no-whole-archive" "-Wl,-Bdynamic" "-lexecinfo" "-lpthread" "-lrt" "-lgcc_s" \
"-lpthread" "-lc" "-lm" "-shared" "-lcompiler-rt"
note: /usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib: file not recognized: File format not recognized

error: aborting due to previous error
/usr/home/aidan/rust/rust/mk/target.mk:166: recipe for target 'x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/stamp.std' failed
gmake: *** [x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/stamp.std] Error 101

The problem seems to be that the FreeBSD linker expects "-L" to be a single argument, while rustc is splitting it into two arguments, "-L" and "". Running the following command line by hand:

"cc" "-L/usr/local/lib" "-L/usr/local/lib/gcc46" "-L/usr/local/lib/gcc44" "-m64" \
"-L/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib" \
"-o" "x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/libstd-4e7c5e5c.so" \
"x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/std-4e7c5e5c.o" \
"-Wl,--whole-archive" "-lmorestack" "-Wl,--no-whole-archive" \
"x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/std-4e7c5e5c.metadata.o" \
"-nodefaultlibs" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/libcollections-4e7c5e5c.rlib" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/librand-4e7c5e5c.rlib" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/liballoc-4e7c5e5c.rlib" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/libunicode-4e7c5e5c.rlib" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/liblibc-4e7c5e5c.rlib" \
"/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib/libcore-4e7c5e5c.rlib" \
"-Lx86_64-unknown-freebsd/rt" \
"-L/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/llvm/Release+Asserts/lib" \
"-L" \
"-L/usr/home/aidan/rust/rust/x86_64-unknown-freebsd/stage1/lib/rustlib/x86_64-unknown-freebsd/lib" \
"-L/usr/home/aidan/rust/rust/.rust/lib/x86_64-unknown-freebsd" \
"-L/usr/home/aidan/rust/rust/lib/x86_64-unknown-freebsd" "-Wl,--whole-archive" \
"-Wl,-Bstatic" "-lrust_builtin" "-lbacktrace" "-lrustrt_native" "-Wl,--no-whole-archive" \
"-Wl,-Bdynamic" "-lexecinfo" "-lpthread" "-lrt" "-lgcc_s" "-lpthread" "-lc" "-lm" \
"-shared" "-lcompiler-rt"

(same as before, but with -L and <path> arguments merged into a single argument)

This allowed the link to succeed.

[rprichard]

I suspect the problem stems from the curious -L "". That's passing two arguments, the second of which is blank.

From my testing so far (on Linux), neither rustc nor clang/gcc treat -L "" as a synonym for -L., so I'm not sure what it actually accomplishes, if anything. rustc passes both arguments to cc. The compiler drivers merge the two-argument form into a single-argument form for passing to ld.

However, Linux's ld actually accepts both the single-argument and two-argument forms. When the command-line has -L "" on it, it corrupts the subsequent argument:

mkdir subdir
echo "void dummy(void){}" > subdir/dummy.c
gcc -shared subdir/dummy.c -o subdir/libdummy.so
echo  >main.rs '#[link(name = "dummy", kind = "dylib")]'
echo >>main.rs 'extern { fn dummy(); }'
echo >>main.rs 'fn main() { unsafe { dummy(); } }'
rustc main.rs -L "" -Lsubdir

Produces:

error: linking with `cc` failed: exit code: 1
note: "cc" "-Wl,--as-needed" "-m64" "-L" "/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "./main" "./main.o" "-Wl,--whole-archive" "-lmorestack" "-Wl,--no-whole-archive" "-Wl,--gc-sections" "-pie" "-nodefaultlibs" "/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd-4e7c5e5c.rlib" "/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcollections-4e7c5e5c.rlib" "/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libunicode-4e7c5e5c.rlib" "/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/librand-4e7c5e5c.rlib" "/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/liballoc-4e7c5e5c.rlib" "/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/liblibc-4e7c5e5c.rlib" "/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib/libcore-4e7c5e5c.rlib" "-L" "" "-L" "subdir" "-L" "/usr/local/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-L" "/home/rprichard/mess/dyncrate/.rust/lib/x86_64-unknown-linux-gnu" "-L" "/home/rprichard/mess/dyncrate/lib/x86_64-unknown-linux-gnu" "-Wl,--whole-archive" "-Wl,-Bstatic" "-Wl,--no-whole-archive" "-Wl,-Bdynamic" "-ldummy" "-ldl" "-lpthread" "-lrt" "-lgcc_s" "-lpthread" "-lc" "-lm" "-lcompiler-rt"
note: /usr/bin/ld: cannot find -ldummy
collect2: error: ld returned 1 exit status

Remove the -L "", or move it to the end of the command-line, and it works. ld is seeing -L -Lsubdir, so it adds the non-existent -Lsubdir directory to the search path, and it doesn't search inside subdir.

[rprichard]

@aidancully What versions of tools are you using? e.g.:

uname -a
cc --version
ld --version
rustc --version --verbose

[rprichard]

I think the -L "" is coming from here in mk/target.mk:

    $(Q)CFG_LLVM_LINKAGE_FILE=$$(LLVM_LINKAGE_PATH_$(3)) \
        $$(subst @,,$$(STAGE$(1)_T_$(2)_H_$(3))) \
        $$(RUST_LIB_FLAGS_ST$(1)) \
        -L "$$(RT_OUTPUT_DIR_$(2))" \
        -L "$$(LLVM_LIBDIR_$(2))" \
        -L "$$(dir $$(LLVM_STDCPP_LOCATION_$(2)))" \
        $$(RUSTFLAGS_$(4)) \
        --out-dir $$(@D) \
        -C extra-filename=-$$(CFG_FILENAME_EXTRA) \
        $$<

I suspect LLVM_STDCPP_LOCATION_$(2) is normally blank (mk/llvm.mk):

ifeq ($$(CFG_ENABLE_LLVM_STATIC_STDCPP),1)
LLVM_STDCPP_LOCATION_$(1) = $$(shell $$(CC_$(1)) $$(CFG_GCCISH_CFLAGS_$(1)) \
                    -print-file-name=libstdc++.a)
else
LLVM_STDCPP_LOCATION_$(1) =
endif

[rprichard]

I was able to reproduce the problem on FreeBSD 9.2. Doing so required compiling and installing libcxxrt and libc++ from the FreeBSD source tree.

The important thing is that cc is cc (GCC) 4.2.1 20070831 patched [FreeBSD] on FreeBSD 9.2. Rather than converting two-argument -L to single-argument -L, this driver propagates both forms to ld unmodified, except that the "" argument in -L "" is dropped. We see something like -L -L <path> on the ld command-line, so of course ld thinks <path> is an input file.

I'm inclined to say that gcc and clang are both buggy, but even if they're fixed, it would take too long to propagate fixes. I'll see how hard this is to fix in the Rust makefile. We may want to fix rustc to either ignore -L "" or reject it.

[aidancully]

@rprichard I think you're right about the problem being the odd -L "". I am building on FreeBSD 9.2 with a re-installed libcxxrt and libc++ (long story). To answer your questions:

$ cc --version
cc (GCC) 4.2.1 20070831 patched [FreeBSD]
Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ ld --version
GNU ld 2.17.50 [FreeBSD] 2007-07-03
Copyright 2007 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License.  This program has absolutely no warranty.

Rustc was the stage1 rustc compiled from 95d9046.

Thanks!