This patchset removes the ad-hoc debug code in target-arm for
identifying cases where we leaked TCG temporary variables, in
favour of an implementation in tcg itself.
Generally any temporaries created by a target while it is
translating an instruction should be freed by the end of that
instruction; otherwise carefully crafted guest code could cause
TCG to run out of temporaries and assert.
Putting the leak-debugging code into TCG proper (a) makes more
sense as this isn't at all arm-specific (b) makes it more
comprehensive, as it now covers temporaries created in all ways,
not just via the new_tmp()/dead_tmp() wrapper functions
(c) avoids annoying false positives where eg a TCG temp created
with tcg_const_i32() was passed to dead_tmp().
The tracking only happens if qemu was configured with
--enable-debug-tcg. It should be easy to add to other targets if
desired; it's just a matter of calling tcg_clear_temp_count()
and tcg_check_temp_count() in the appropriate places.
Changes since v1:
use "do { } while (0)" for the non-debug version of the
tcg_clear_temp_count() macro to avoid creating empty statements
Peter Maydell (3):
tcg: Add support for debugging leakage of temporaries
target-arm: Remove ad-hoc leak checking code
target-arm: Use TCG temporary leak debugging facilities
target-arm/translate.c | 705 +++++++++++++++++++++++------------------------
tcg/tcg.c | 32 +++
tcg/tcg.h | 17 ++
3 files changed, 394 insertions(+), 360 deletions(-)
