I was very frustrated by the lack of debug-info at the gdb prompt during
rust coding recently. I note too that people on #rust complain about the
lack of visibility into debugging rustc itself.
I think there is a lightweight, quick to implement, solution to these
problems.
I have in mind a
Please note that Michael Woerister's work this summer on debug symbols has
been wildly successful, and it's worth giving it another shot before
looking into further compiler hacking:
http://michaelwoerister.github.io/2013/09/27/what-you-call-the-present.html
Cheers,
Josh
On 30 September 2013
Hi Josh,
Could you be more specific about what you would like me to try? When I
iniquire on #rust I'm told that debug-info is still in bad shape.
Specifically: I do rustc -Z debug-info -Z extra-debug-info -Z no-opt, and I
consistently get no local variables showing up in gdb on any stack frame.
surely global_tracking_flag could be persuaded to live in a register, no?
Reserving a register will slow down the whole program. I'd expect a serious
hit on 32-bit x86, and modest but measurable slowdown elsewhere. It might be
worth doing a quick experiment, if there's a way to convince LLVM
Interesting idea, the self-modifying code. Is that codable in rust
currently?
On Mon, Sep 30, 2013 at 1:06 PM, Keegan McAllister
kmcallis...@mozilla.comwrote:
surely global_tracking_flag could be persuaded to live in a register, no?
Reserving a register will slow down the whole program.
I'm wondering if much of this couldn't be prototyped with macros. Is there
a way for a macro to refer to the return value of a function?
On Mon, Sep 30, 2013 at 1:13 PM, Jason E. Aten j.e.a...@gmail.com wrote:
Interesting idea, the self-modifying code. Is that codable in rust
currently?
Currently you can't do that with macros, but in theory you could crate
a wrapper macro to declare all your functions which works similarly to
the externfn! macro. It could debug entry/exit and otherwise just be a
wrapper around an internally declared function.
On Mon, Sep 30, 2013 at 1:35 PM,
Is that codable in rust currently?
Well, there are two parts to this: the automatic insertion of logging calls,
and the runtime feature to enable/disable them. The former would be part of
the compiler and can directly emit appropriate LLVM along with table entries to
say what should be NOP'd
Hi Josh,
I'm told that rustc itself is a prime example. People on #rust were
complaining about how opaque it is, and telling me printfs were the only
recourse. Are you saying you *are* able to step through rustc?
I filed a ticket for the stuff that was frustrating me--stepping through
the
surely global_tracking_flag could be persuaded to live in a register, no?
No. Although this is implemented in GCC, this is unimplemented in LLVM and
upstream is not keen on implementing it.
See Global Register Variables note at http://nondot.org/sabre/LLVMNotes/
and LLVM bug 16877.
10 matches
Mail list logo
