On Fri, Mar 15, 2013 at 11:31 AM, Adrian Prantl <[email protected]> wrote: > > On Mar 15, 2013, at 11:26 AM, David Blaikie <[email protected]> wrote: > >> On Fri, Mar 15, 2013 at 10:46 AM, Adrian Prantl <[email protected]> wrote: >>> >>> On Mar 15, 2013, at 10:25 AM, David Blaikie <[email protected]> wrote: >>> >>>> On Fri, Mar 15, 2013 at 10:09 AM, Adrian Prantl <[email protected]> wrote: >>>>> Author: adrian >>>>> Date: Fri Mar 15 12:09:05 2013 >>>>> New Revision: 177164 >>>>> >>>>> URL: http://llvm.org/viewvc/llvm-project?rev=177164&view=rev >>>>> Log: >>>>> Force column info only for direct inlined functions. This should strike >>>>> the balance between expected behavior and compatibility with the gdb >>>>> testsuite. >>>>> >>>>> (GDB gets confused if we break an expression into multiple debug >>>>> stmts so we enable this behavior only for inlined functions. For the >>>>> full experience people can still use -gcolumn-info.) >>>> >>>> I'm not sure I understand how this will address the issue... Perhaps >>>> I'm misunderstanding something about this change. I have a few >>>> questions/uncertainties: >>> >>>> 1) You can't really determine in the frontend if a function will >>>> actually be inlined - trying to predicate debug info on that seems >>>> like we'll get surprising/varying debug behavior based on whether the >>>> backend chooses to inline the function >>> >>> That is correct. My thinking was that the backend would only inline at >O0 >>> and if you need more precise debug info you could always use -gcolumn-info. >>> But for those cases where function is inlined at O0 (which happens for >>> inline-attributed functions and is done by the frontend) users will get the >>> expected behavior. >>> This is not very elegant, but I’m trying to find a middle ground between >>> not breaking gdb’s testsuite and fixing the debug experience for inlined >>> functions. >> >> Sure - I'm not suggesting that we should not fix the original bug you >> set out to fix, just that the solution that Eric & I were >> discussing/suggesting wasn't what you've implemented here. I thought >> what we were discussing was changing the backend to not emit separate >> line table entries when the line is the same but the column is >> different. This would be consistent with the debug experience users >> expect (given GDB's lack of column information) in all cases, no >> matter what things were inlined or not inlined, if I'm not mistaken. > > As I mentioned earlier, the problem is that for inlined functions we need to > do exactly that otherwise a breakpoint at the inlined function (appearing > twice on one line) would be hit only once.
Still feels wrong in some way - mostly because of the inlining possibilities (both not inlining when your frontend heuristic would indicate that it does, and inlining when it doesn't), even at -O0 (we still do inlining, even on non-always_inline functions, at -O0 - for simple functions like get/set, etc) FWIW, GCC does exhibit the same behavior you described when it inlines a function (if I use the func(foo(), bar()) example & make foo/bar always_inline, then stepping through goes foo/func call/bar and stepping through without the always_inline goes foo/bar) I would like this to be done right so it behaves appropriately regardless of whether the backend chooses to inline the foo/bar calls. _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
