Hi Thomas, On 26/09/18 18:39, Thomas Preudhomme wrote:
Hi,GCC ICEs under -mslow-flash-data and -mword-relocations because there is no way to load an address, both literal pools and MOVW/MOVT being forbidden. This patch gives an error message when both options are specified by the user and adds the according dg-skip-if directives for tests that use either of these options. ChangeLog entries are as follows: *** gcc/ChangeLog *** 2018-09-25 Thomas Preud'homme <thomas.preudho...@linaro.org> PR target/87374 * config/arm/arm.c (arm_option_check_internal): Disable the combined use of -mslow-flash-data and -mword-relocations. *** gcc/testsuite/ChangeLog *** 2018-09-25 Thomas Preud'homme <thomas.preudho...@linaro.org> PR target/87374 * gcc.target/arm/movdi_movt.c: Skip if both -mslow-flash-data and -mword-relocations would be passed when compiling the test. * gcc.target/arm/movsi_movt.c: Likewise. * gcc.target/arm/pr81863.c: Likewise. * gcc.target/arm/thumb2-slow-flash-data-1.c: Likewise. * gcc.target/arm/thumb2-slow-flash-data-2.c: Likewise. * gcc.target/arm/thumb2-slow-flash-data-3.c: Likewise. * gcc.target/arm/thumb2-slow-flash-data-4.c: Likewise. * gcc.target/arm/thumb2-slow-flash-data-5.c: Likewise. * gcc.target/arm/tls-disable-literal-pool.c: Likewise. Testing: Bootstrapped in Thumb-2 mode. No testsuite regression when targeting arm-none-eabi. Modified tests get skipped as expected when running the testsuite with -mslow-flash-data (pr81863.c) or -mword-relocations (all the others). Is this ok for trunk? I'd also appreciate guidance on whether this is worth a backport. It's a simple patch but on the other hand it only prevents some option combination, it does not fix anything so I have mixed feelings.
In my opinion -mslow-flash-data is more of a tuning option rather than a security/ABI feature and therefore erroring out on its combination with -mword-relocations feels odd. I'm leaning more towards making -mword-relocations or any other option that really requires constant pools to bypass/disable the effects of -mslow-flash-data instead. For me, as a user, it would give a more friendly experience. That said, you have more familiarity with M-profile users. Would such users prefer a hard error when the -mslow-flash-data option has its effects bypassed? Maybe we could emit a warning rather than an error when this happens? Thanks, Kyrill
Best regards, Thomas
