Subject: Re: publishing
From: Sorin Lerner (lerns@cs.washington.edu)
Date: Sun Nov 12 2000 - 21:41:39 PST
Recompiling from scratch solve the segfault problem.
Sorin
Craig Chambers wrote:
> I don't know why my publish isn't setting the other read permission on ,v files,
> while you all are. Maybe I have a umask set that shouldn't be. But in any
> case, I've made all the ,v files world-readable.
>
> I don't know what the segfault problem is. Are you trying to reuse an old
> snapshot (.db file)? If so, are you getting any warnings that it might be out
> of date (missing fields, etc.)? If so, then you can get a segfault by trying to
> use an out-of-date checkpoint. Just recompile from scratch to build a new
> checkpoint.
>
> If that's not the problem, then I don't know what's up. My version works. It's
> possible that some change you made is incompatible with my changes, and they're
> clashing.
>
> BTW, segfault either means you're trying to reuse a checkpoint after you were
> warned it might not work, or you got an infinite recursion leading to stack
> overflow. For the latter, I try to see where things are hanging, and hit ^C
> just before where I would get the segfault to enter the Vortex debugger, and
> dump the stack to see where the infinite recursion is.
>
> I've been thinking recently that some Vortex debugger support to check if the
> stack is getting deep, and take a breakpoint whenever the stack is e.g. more
> than 1000 frames deep, or some number of KB deep.
>
> -- Craig
>
> Sorin Lerner wrote:
> >
> > I updated my copy of the repository, and I'm now getting a segfault when
> > compiling even the smallest wil file. Todd seems to have hit the same
> > problem. I tried looking at the stack trace of the core dump with gdb,
> > but I didn't see any symbols.
> >
> > Sorin
> >
> > Craig Chambers wrote:
> >
> > > I'm publishing a bunch of useful improvements to Whirlwind.
> > >
> > > *) I reorganized some of the graph visit code to allow multiple kinds
> > > of visits, each of which can be run in parallel with other visit kinds
> > > (but not with other instances of the same kind on the same IR), as
> > > well as a general visit kind that can be run in parallel arbitrarily.
> > > I've changed the printing visits to be a different kind than the
> > > others, so that you can print the graph while you're in the middle of
> > > some other visit, e.g. during an analysis.
> > >
> > > *) I implemented dot-based graph visualization. There are three new
> > > options, show_dot_cfgs, show_dot_dfgs, and show_dot_cdfgs, which if
> > > turned on will ask you whether you want to display the graph. Try it
> > > out. It has already revealed that my dataflow graph building
> > > algorithm breaks for references to global variables.... (Perhaps just
> > > those defined textually in a different file. I think the fix to this
> > > and other known DFG problems is to leave in variable references as
> > > root DFG nodes whenever there's no definition computed for the
> > > variable. (This may still not work in the face of conditional local
> > > assignments to a variable, but it should work a lot better.)) I
> > > haven't tested this exhaustively, but it at least works to some
> > > extent. Let me know if you find problems.
> > >
> > > *) I reorganized how nested IR nodes are compiled. Now, each IR is
> > > compiled to completion, running all the various passes, before
> > > proceeding on to any nested IRs. This makes each pass easier to
> > > handle, since it doesn't recursively perform that pass on all nested
> > > IRs. It also makes the resulting graph visualizations easier to deal
> > > with. It also made it easier to support processing the global IRs
> > > separately from all the nested IRs.
> > >
> > > *) IRs now explicitly store their nested IRs, and some existing code
> > > has been rewritten to explicitly use these lists.
> > >
> > > *) I factored out the scope-building code from the name-resolution
> > > code.
> > >
> > > *) I spent a lot of time rationalizing the compress & invalidate code.
> > >
> > > *) I wrote some code to automatically indent phase time reporting
> > > within their enclosing phases, but it's not well tested.
> > >
> > > *) I fixed what I think is a bug with analysis of replacement graphs
> > > that have dangling outgoing edges. The framework now sets their edge
> > > info explicitly to the analysis's top info.
> > >
> > > *) I explicitly insert Enter and ExitScopeNodes around the top-level
> > > statements, so they don't need to be special-cased in the codegen
> > > analysis. (Todd, you should copy my simplifications into your code.)
> > >
> > > *) I did some reformatting of the WIL parser code, just so it conforms
> > > more to "standard" (i.e. "my") Cecil style.
> > >
> > > *) I defined standard print[_recursively] and verify[_recursively]
> > > operations on slices, which just forward to the preexisting
> > > slice-specific functions.
> > >
> > > *) I added some more comments. :)
> > >
> > > There's a known bug in this publish (and probably in previous systems
> > > too): if you modify/touch a file and then try to recompile, the
> > > incremental reconstruction of the global scope info crashes with
> > > duplicate declaration errors. I have to do some work to handle
> > > incremental rebuilds after programming changes. For now, Just Say No
> > > (to input program changes). Or do "invalidate" before doing any
> > > graphs/typecheck/make operation where the program has changed.
> > >
> > > -- Craig
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