a nested copy constructor with unclosed parentheses, if
nested sufficiently deeply, exhausts memory and kills the
compiler after several minutes of churning.
class C;
C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(
// (40 nested unclosed constructor parentheses)
in the syntactically correct case, the compile finishes
in less than one second.
class C;
C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C())))))))))))))))))))))))))))))))))))))));
i've tested on both RedHat FC7 and Solaris 10/Intel, and
the behavior is the same. below is the FC7 output.
phoenix% /opt/gcc-4.4.0/bin/g++ -v -save-temps -c bug.C
Using built-in specs.
Target: x86_64-unknown-linux-gnu
Configured with: ./configure --prefix=/opt/gcc-4.4.0
--with-mpfr=/opt/mpfr-2.4.1
Thread model: posix
gcc version 4.4.0 (GCC)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-c' '-shared-libgcc' '-mtune=generic'
/opt/rw/gcc-4.4.0/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.4.0/cc1plus -E
-quiet -v -iprefix
/opt/rw/gcc-4.4.0/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/ -D_GNU_SOURCE
bug.C -mtune=generic -fpch-preprocess -o bug.ii
ignoring nonexistent directory
"/opt/rw/gcc-4.4.0/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../x86_64-unknown-linux-gnu/include"
ignoring duplicate directory
"/opt/rw/gcc-4.4.0/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../include/c++/4.4.0"
ignoring duplicate directory
"/opt/rw/gcc-4.4.0/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../include/c++/4.4.0/x86_64-unknown-linux-gnu"
ignoring duplicate directory
"/opt/rw/gcc-4.4.0/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../include/c++/4.4.0/backward"
ignoring duplicate directory
"/opt/rw/gcc-4.4.0/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/include"
ignoring duplicate directory
"/opt/rw/gcc-4.4.0/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/include-fixed"
ignoring nonexistent directory
"/opt/rw/gcc-4.4.0/bin/../lib/gcc/../../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../x86_64-unknown-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/opt/rw/gcc-4.4.0/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../include/c++/4.4.0
/opt/rw/gcc-4.4.0/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../include/c++/4.4.0/x86_64-unknown-linux-gnu
/opt/rw/gcc-4.4.0/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/../../../../include/c++/4.4.0/backward
/opt/rw/gcc-4.4.0/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/include
/opt/rw/gcc-4.4.0/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.4.0/include-fixed
/usr/local/include
/opt/rw/gcc-4.4.0/bin/../lib/gcc/../../include
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-c' '-shared-libgcc' '-mtune=generic'
/opt/rw/gcc-4.4.0/bin/../libexec/gcc/x86_64-unknown-linux-gnu/4.4.0/cc1plus
-fpreprocessed bug.ii -quiet -dumpbase bug.C -mtune=generic -auxbase bug
-version -o bug.s
GNU C++ (GCC) version 4.4.0 (x86_64-unknown-linux-gnu)
compiled by GNU C version 4.4.0, GMP version 4.1.4, MPFR version 2.4.1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: b0ba9d2a53d0754610d55da75a5fe542
[wait 6 minutes]
g++: Internal error: Killed (program cc1plus)
Please submit a full bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
system type:
phoenix% uname -a
Linux phoenix 2.6.22.9-91.fc7 #1 SMP Thu Sep 27 20:47:39 EDT 2007
x86_64 x86_64 x86_64 GNU/Linux
source file:
phoenix% cat bug.C
class C;
C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(C(
// (40 nested unclosed constructor parentheses)
expected behavior:
bug.C:2: error: expected unqualified-id at end of input
bug.C:2: error: expected `)' at end of input
actual behavior:
compiler runs for a long time, filling memory, until killed by OS.
it seems to be a recursion problem. the code "class C; C(" fails
immediately.
every additional nesting of unclosed parentheses doubles the compile
time (and
the memory used) until finally with enough unclosed nestings, memory is
exhausted
and the OS kills the compiler process.
however, it is specific to constructors. this code fails immediately:
> int f(int);
>
f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(f(
--
Summary: cc1plus exhausts memory with deeply nested unclosed
constructor parens
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: cbm at whatexit dot org
GCC build triplet: x86_64-unknown-linux-gnu
GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39992
