[Lldb-commits] [PATCH] D35740: Fix PR33875 by distinguishing between DWO and clang modules

[Adrian Prantl via lldb-commits]

> On Jul 22, 2017, at 2:26 PM, David Blaikie <dblaikie at gmail.com> wrote:
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> On Fri, Jul 21, 2017 at 6:14 PM Jim Ingham <jingham at apple.com <mailto:jingham at apple.com>> wrote:
> Not at present, but you presumably know more about this than I do.  Part of the point of Greg's extracting the DWARF parser from lldb and making it into it's own library in llvm was precisely so that somebody could then write a simple wrapper tool that would poke it with not necessarily complete but interesting canned bits of DWARF and see that it does the right thing.  I thought you were involved with the reviews for that work?
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> Yep yep - though not necessarily clear on the bigger picture goals in terms of which components were going where in the long term.
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>   I was not paying attention to the details of that effort as DWARF parsing's not really my thing.
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> Anyway, the extraction of the DWARF parser was Greg's last act before leaving Apple, and the project stalled at that point.  I don't imagine he could have gotten that code into llvm without some testing, so the kind of test you are thinking of should be done using whatever mechanism you guys devised for the new llvm dwarf parser. 
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> Adrian - any chance something like the DwarfGenerator stuff in LLVM could be used to test this code?
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> Of course, it's less interesting to test the llvm version of the DWARF parser if lldb's not using it, so for that to be directly relevant here that piece of work would need to be done.
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> Perhaps - or reusing the same testing approach without that. Though I think this particular failure/fix was in a higher/lower different layer than the pure parsing stuff in LLVM, but I could be wrong - there's sufficient divergence it's not obvious from a few class names, etc, to tell how much overlap (& where) there is.

Yes, I would also say that this is one level above the pure parsing. This is how LLDB interprets the data. Once the LLVM DWARF parser (which is architected more for testability) is complete enough to be used inside LLDB, there is no reason to not also implement this level (cross-referencing dwarf+dwo) inside LLVM and properly test with a unit test or a yaml object description. Inside LLDB an end-to-end test like the existing one is as good as it gets now.

-- adrian
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> Jim
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> > On Jul 21, 2017, at 5:51 PM, David Blaikie <dblaikie at gmail.com <mailto:dblaikie at gmail.com>> wrote:
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> > On Fri, Jul 21, 2017 at 4:05 PM Greg Clayton via Phabricator <reviews at reviews.llvm.org <mailto:reviews at reviews.llvm.org>> wrote:
> > clayborg accepted this revision.
> > clayborg added a comment.
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> > Looks like there already is a test case that was failing as Jim mentioned. Accepting based on that.
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> > Ah, I was thinking more a test that would've failed when LLDB regressed (regardless of whether Clang was still producing this DWARF or not) - does LLDB have tests like that? (either binary, asm, or some other terse way of writing DWARF directly to test "does LLDB do the right thing with this DWARF" sort of tests?)
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> > https://reviews.llvm.org/D35740 <https://reviews.llvm.org/D35740>
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