ICE when building ziproxy

gcc fails to build the attached testcase with optimization levels above -O0. The problem occurs with all versions from the gcc 4.x branch. Versions gcc 3.x do not expose the problem. Note that the ICE occurs on both old-ABI and EABI.

Using built-in specs.
Target: arm-linux-gnueabi
Configured with: ../src/configure -v --with-pkgversion='Debian 4.3.0-5' --with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.3 --program-suffix=-4.3 --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc --enable-mpfr --disable-libssp --disable-sjlj-exceptions --enable-checking=release --build=arm-linux-gnueabi --host=arm-linux-gnueabi --target=arm-linux-gnueabi
Thread model: posix
gcc version 4.3.1 20080523 (prerelease) (Debian 4.3.0-5)

Created attachment 15731
reduced testcase

Confirmed with gcc-4.3.2-1 Debian gnueabi:
$ gcc -c -O1 pr36466.c
pr36466.c: In function ‘ReadCfgFile’:
pr36466.c:19: internal compiler error: in choose_reload_regs, at reload1.c:6190

And on trunk rev 142984:
pr36466.c: In function 'ReadCfgFile':
pr36466.c:19: internal compiler error: in choose_reload_regs, at reload1.c:6470

backtrace on trunk:

(gdb) bt
#0 fancy_abort (file=0x786084 "../../trunk/gcc/reload1.c", line=6470, function=0x785f8c "choose_reload_regs") at ../../trunk/gcc/diagnostic.c:712
#1 0x002ba378 in choose_reload_regs (chain=<value optimized out>) at ../../trunk/gcc/reload1.c:6470
#2 0x002baf08 in reload_as_needed (live_known=<value optimized out>) at ../../trunk/gcc/reload1.c:4240
#3 0x002bf868 in reload (first=<value optimized out>, global=<value optimized out>) at ../../trunk/gcc/reload1.c:1169
#4 0x0068815c in rest_of_handle_ira () at ../../trunk/gcc/ira.c:2018
#5 0x0026ebc8 in execute_one_pass (pass=0x91fa54) at ../../trunk/gcc/passes.c:1279
#6 0x0026ee34 in execute_pass_list (pass=0x91fa54) at ../../trunk/gcc/passes.c:1328
#7 0x0026ee4c in execute_pass_list (pass=0x91a390) at ../../trunk/gcc/passes.c:1329
#8 0x003726f4 in tree_rest_of_compilation (fndecl=0x40232780) at ../../trunk/gcc/tree-optimize.c:419
#9 0x004e92d4 in cgraph_expand_function (node=0x401b0900) at ../../trunk/gcc/cgraphunit.c:1047
#10 0x004eb35c in cgraph_optimize () at ../../trunk/gcc/cgraphunit.c:1106
#11 0x0001cabc in c_write_global_declarations () at ../../trunk/gcc/c-decl.c:8074
#12 0x0031e58c in toplev_main (argc=<value optimized out>, argv=<value optimized out>) at ../../trunk/gcc/toplev.c:981
#13 0x40095dfc in __libc_start_main () from /lib/libc.so.6
#14 0x0000aa7c in _start ()

I see the same problem when I try to compile transmission release 1.73. The error happens with file libtransmission/fdlimit.c. Works till -O1 but fails with -O2 or -O3. Seeing this error with gcc 4.21.

Transmission was configured with:
./configure --host=arm-none-linux-gnueabi --target=arm-none-linux-gnueabi \
                        --build=i686-pc-linux \
                        --disable-gtk --disable-nls \
                        --prefix=/usr/local \
                        CFLAGS="-I/home/user/proj/syno-packager/precomp/88f6281/arm-none-linux-gnueabi/include -I/home/user/proj/syno-packager/out/88f6281/temproot/usr/local/include -I/home/user/proj/syno-packager/out/88f6281/root/usr/local/include" LDFLAGS="-L/home/user/proj/syno-packager/precomp/88f6281/arm-none-linux-gnueabi/lib -L/home/user/proj/syno-packager/out/88f6281/temproot/usr/local/lib -L/home/user/proj/syno-packager/out/88f6281/root/usr/local/lib"

Transmission needs openssl and curl to compile. So if you want to reproduce this issue, you might have to compile them first.

Please email me if you need further data.

Thanks,
SK

Confirmed with gcc-4.3-20090802, gcc-4.4-20090728, and gcc-4.5-20090730. Passing -mtune=xscale to gcc prevents the ICE.

Hang on, the test case looks invalid:

> ReadCfgFile (char *cfg_file)
> {
> void *conf_handler;
> int i;
> struct sockaddr_in nsaddr_list[0];
> char *nserver_str;
> qp_getconf_array_str (conf_handler, "Nameservers", i, &nserver_str, 0);
> (*__res_state ()).nsaddr_list[(*__res_state ()).nscount++] = nsaddr_list[0];
> }

This has a zero-element array as a local variable, which it then fetches an element from. That's clearly invalid. Changing it as follows

- struct sockaddr_in nsaddr_list[0];
+ struct sockaddr_in nsaddr_list[1];

makes the test case work for me, even without -mtune=xscale.

Invalid testcase as per comment #6.

(In reply to comment #4)
> I see the same problem when I try to compile transmission release 1.73. The
> error happens with file libtransmission/fdlimit.c. Works till -O1 but fails
> with -O2 or -O3. Seeing this error with gcc 4.21.
>

Please file a separate bug report about this as per http://gcc.gnu.org/bugs.html if you can reproduce this for trunk or any of the current release branches.

I'm not sure how the .i ends up with a zero-length array; resolv.h has:
# define MAXNS 3 /* max # name servers we'll track */
[...]
struct __res_state {
[...]
        struct sockaddr_in
                nsaddr_list[MAXNS]; /* address of name server */

so it should be [3], but it's [0] in the .i file attached here.

Also, even if it's invalid input, I guess gcc should never SEGV, but rather throw an error out?

Reopening since GCC should not ICE, even if the code is invalid.

Reopening.

Ok, it's [0] because ziproxy uses "nsaddr" as an identifier for a local variable which conflicts with a compatibility #define in glibc resolv.h. Renaming to "nsaddress" for instance fixes the build, so clearly bogus source code.

gcc-4.6 seems to compile the code without generating an ICE. However, versions of gcc older than 4.7 are no-longer being maintained.