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author | Andrew Burgess <andrew.burgess@embecosm.com> | 2018-08-29 18:49:51 +0100 |
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committer | Andrew Burgess <andrew.burgess@embecosm.com> | 2018-08-30 16:33:49 +0100 |
commit | c67f2e1518a829c4ae4f346c316701ef5d56a30f (patch) | |
tree | 632ff9a1f8a9ac701bab13bb93a2bfc874034961 /gdb/target-delegates.c | |
parent | a0dc02a6df86011462293cc11b4e35c0f18effd0 (diff) | |
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gdb: Ensure compiler doesn't optimise variable out in test
In the test gdb.base/funcargs.exp, there's this function:
void recurse (SVAL a, int depth)
{
a.s = a.i = a.l = --depth;
if (depth == 0)
hitbottom ();
else
recurse (a, depth);
}
The test script places a breakpoint in hitbottom, and runs the
executable which calls recurse with an initial depth of 4.
When GDB hits the breakpoint in hitbottom the testscript performs a
backtrace, and examines 'a' at each level.
The problem is that 'a' is not live after either the call to
'hitbottom' or the call to 'recurse', and as a result the test fails.
In the particular case I was looking at GCC for RISC-V 32-bit, the
variable 'a' is on the stack and GCC selects the register $ra (the
return address register) to hold the pointer to 'a'. This is fine,
because, by the time the $ra register is needed to hold a return
address (calling hitbottom or recurse) then 'a' is dead.
In this patch I propose that a use of 'a' is added after the calls to
hitbottom and recurse, this should cause the compiler to keep 'a'
around, which should ensure GDB can find it.
gdb/testsuite/ChangeLog:
* gdb.base/funcargs.c (use_a): New function.
(recurse): Call use_a.
Diffstat (limited to 'gdb/target-delegates.c')
0 files changed, 0 insertions, 0 deletions