Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 19 Apr 2012 17:40:07 -0700 | Subject | Re: [GIT PULL 00/13] Annotation improvements (G+ edition) |
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On Thu, Apr 19, 2012 at 5:31 PM, Linus Torvalds <torvalds@linux-foundation.org> wrote: > On Thu, Apr 19, 2012 at 1:33 PM, Arnaldo Carvalho de Melo > (crappy) arrow head to find possible loops (backwards jumps). > > The above snippet would then become: > > 2.08 test %rdx,%rdx > 0.00 jne 38 ----v > 0.00 jmp 53 ----v > 5.13 30: mov (%rdx),%rdx > 0.74 test %rdx,%rdx > 0.00 je 53 ----v > 0.06 38: lea -0x20(%rdx),%rax > 59.64 cmp -0x20(%rdx),%edi > 0.40 jne 30 ----^ > 17.36 cmp -0x18(%rdx),%cx > 0.00 jne 30 ----^ > 1.91 cmp 0x4(%rax),%esi > 0.00 jne 30 ----^ > 0.22 test %rax,%rax > 0.20 je 53 ----v > 1.68 leaveq > 1.90 retq > 0.00 53: incl %gs:0xe214 > 0.00 xor %eax,%eax
Side note: I'm not at all certain that the arrows should be at the end of the line. It might be even better to show it at the head of the line, ie something like
2.08 test %rdx,%rdx 0.00 v jne 38 0.00 v jmp 53 5.13 30: mov (%rdx),%rdx 0.74 test %rdx,%rdx 0.00 v je 53 0.06 38: lea -0x20(%rdx),%rax 59.64 cmp -0x20(%rdx),%edi 0.40 ^-- jne 30 17.36 cmp -0x18(%rdx),%cx 0.00 ^-- jne 30 1.91 cmp 0x4(%rax),%esi 0.00 ^-- jne 30 0.22 test %rax,%rax 0.20 v je 53 1.68 leaveq 1.90 retq 0.00 53: incl %gs:0xe214 0.00 xor %eax,%eax
but then you obviously need to make it work right if a branch is also a branch target.
Oh, and one other visual clue that could be useful: unconditional branches (including "ret") that actually end the flow of code and don't have a fallthrough to the next instruction would be nice to see clearly. Even perhaps an empty line following them? Although maybe that would be wasting precious vertical space..
Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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