This usage of a null substitution came up while I was trying to use
this form of spec. for a different switch, but the following illustrates
the problem using the existing gcc compiler as built for Redhat Linux
running on an SGI Altix:
Given a spec of this form,
%{S:X} substitutes X, if the -S switch was given to CC.
And a switch definition for -static:
/* %{static:} simply prevents an error message if the target machine
doesn't handle -static. */
And the resulting link command spec:
*link_command:
%{!fsyntax-only:%{!c:%{!M:%{!MM:%{!E:%{!S: %(linker) %l %{pie:-pie} %X %{o*}
%{A} %{d} %{e*} %{m} %{N} %{n} %{r} %{s} %{t}
%{u*} %{x} %{z} %{Z} %{!A:%{!nostdlib:%{!nostartfiles:%S}}} %{static:} %{L*}
%(link_libgcc) %o
%{fprofile-arcs|fprofile-generate:-lgcov}
%{!nostdlib:%{!nodefaultlibs:%(link_gcc_c_sequence)}}
%{!A:%{!nostdlib:%{!nostartfiles:%E}}} %{T*} }}}}}}
% gcc --version
gcc (GCC) 3.2.3 20030502 (Red Hat Linux 3.2.3-34)
then the command "gcc -static t.c" ultimately yields the
following collect2 command:
/usr/lib/gcc-lib/ia64-redhat-linux/3.2.3/collect2 -static
/usr/lib/gcc-lib/ia64-redhat-linux/3.2.3/../../../crt1.o
/usr/lib/gcc-lib/ia64-redhat-linux/3.2.3/../../../crti.o
/usr/lib/gcc-lib/ia64-redhat-linux/3.2.3/crtbegin.o
-L/usr/lib/gcc-lib/ia64-redhat-linux/3.2.3 -L/usr/lib/gcc-lib/ia64-redhat-linux/
3.2.3/../../.. /tmp/ccc2ISqV.o --start-group -lgcc -lgcc_eh -lc --end-group
/usr/lib/gcc-lib/ia64-redhat-linux/3.2.3/crtend.o
/usr/lib/gcc-lib/ia64-redhat-linux/3.2.3/../../../crtn.o
I haven't followed the logic in detail, but should the spec.
%{static:} above erase the explicit -static switch that was
passed to gcc?
