On February 23, 2019 12:39:42 AM PST, Peter Zijlstra <pet...@infradead.org> wrote: >On Fri, Feb 22, 2019 at 03:39:48PM -0800, h...@zytor.com wrote: >> Objtool could also detect CLAC-STAC or STAC-CLAC sequences without >> memory operations and remove them; don't know how often that happens, >> but I know it *does* happen. > >Objtool doesn't know about memops; that'd be a lot of work. Also, >objtool doesn't actually rewrite the text, at best it could warn about >such occurences.
It doesn't have to understand the contents of the memop, but it seems that the presence of a modrm with mode ≠ 3 should be plenty. It needs to know that much in order to know the length of instructions anyway. For extra credit, ignore LEA or hinting instructions. -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
