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Unused variables in testsuite
- From: Christophe LYON <christophe dot lyon at st dot com>
- To: gdb at sourceware dot org
- Date: Fri, 28 Apr 2006 16:38:56 +0200
- Subject: Unused variables in testsuite
While fixing our compiler, I came across strange tests in the GDB
testsuite: in some source files, some variables are defined but not used
by the code, but are references in the .exp.
Is there anywhere a requirement that the compiler should allocate unused
variable under -O0 ?
For instance, consider the test in gdb.cp/m-static.cc , m-static.h,
You can see that in main() one defines "test4" which is not used, thus
need not be allocated. Then, using "print test4.elsewhere" under GDB
fails. [note that in this case the default (empty) constructor for test4
has no side effects, thus test4 can be eliminated safely]
In the same way, in gdb.mi/var-cmd.c , mi-var-display.exp, you can see
that function do_special_tests() defines several variables (eg 'u') and
does not use them, while the .exp file tries to "-var-create u * u".
I modified these tests so that the variables are used, and they now pass
with our compiler.
May I submit this small patch, or is there a requirement on GCC to
allocate even unused variables in -O0? (our compiler is not GCC)