On 19.01.2014, at 21:52, Peter Maydell <peter.mayd...@linaro.org> wrote:
> On 19 January 2014 20:15, Alexander Graf <ag...@suse.de> wrote: >> On 19.01.2014, at 17:51, Peter Maydell <peter.mayd...@linaro.org> wrote: >>> Exiting is pretty harsh; ARM just warns and continues. > >> Well, the check only ever happens when QEMU gets compiled >> with --enable-debug-tcg, so I figured it's easier for me to catch >> new problems or problems with unit tests if we get a harsh abort :). > > Well, you're the one that gets to field the bug reports for PPC so > it's your call :-) > > Longer term I was wondering if we should define the concept > of a 'scope object' for TCG temporaries, so you create a scope > object and then we have versions of tcg_temp_new_*() that > take a scope object to effectively define the lifetime of that > temp. Destroying the scope object frees every TCG temp in it. > Then we could just have the target frontends create a scope > for each instruction, and they wouldn't need to worry about > manually freeing TCG temporaries within it at all. That seems > better than the current approach where every frontend rolls > its own auto-free mechanism, and would render this sort of > "check for bugs in manual temp freeing" unnecessary too. > > (We could also make the tcg_gen_brcond* functions do a > "free all temps in all scope objects" and then we'd catch > use-of-temp-after-branch bugs, especially if we also got > TCG to assert on use of a dead temporary rather than only > later when it was doing regalloc on it...) I agree - that would be awesome :). We could even go as far as defining a "fallback scope" that's instruction wide. Alex
