On Fri, Jul 19, 2019 at 11:10 AM Arnd Bergmann <[email protected]> wrote: > > A lot of objtool fixes showed up in linux-next, so I looked at some > remaining ones. > This one comes a lot up in some configurations > > https://godbolt.org/z/ZZLVD- > > struct ov7670_win_size { > int width; > int height; > }; > struct ov7670_devtype { > struct ov7670_win_size *win_sizes; > unsigned n_win_sizes; > }; > struct ov7670_info { > int min_width; > int min_height; > struct ov7670_devtype devtype; > } a; > int b; > int fn1() { > struct ov7670_info c = a; > int i = 0; > for (; i < c.devtype.n_win_sizes; i++) { > struct ov7670_win_size d = c.devtype.win_sizes[i]; > if (c.min_width && d.width < d.height < c.min_height) > if (b) > return 0; > } > return 2; > } > > $ clang-8 -O2 -fno-omit-frame-pointer -fno-strict-overflow -c ov7670.i > $ objtool check --no-unreachable --uaccess ov7670.o > ov7670.o: warning: objtool: fn1 uses BP as a scratch register
Thanks for the report and reduced test case. From the godbolt link, I don't see %rbp, %ebp, %bp, or %bpl being referenced (other that %rbp in the typical epilogue). Am I missing something? Is objtool maybe not reporting the precise function at fault? -- Thanks, ~Nick Desaulniers
