On Tue, Nov 18, 2014 at 2:59 AM, David Malcolm <[email protected]> wrote: > On Mon, 2014-11-17 at 11:06 +0100, Richard Biener wrote: >> On Sat, Nov 15, 2014 at 12:00 PM, David Malcolm <[email protected]> wrote: >> > On Thu, 2014-11-13 at 11:45 +0100, Richard Biener wrote: >> >> On Thu, Nov 13, 2014 at 2:41 AM, David Malcolm <[email protected]> >> >> wrote: >> >> > On Tue, 2014-11-11 at 11:43 +0100, Richard Biener wrote: >> >> >> On Tue, Nov 11, 2014 at 8:26 AM, Jakub Jelinek <[email protected]> >> >> >> wrote: >> >> >> > On Mon, Nov 10, 2014 at 05:27:50PM -0500, David Malcolm wrote: >> >> >> >> On Sat, 2014-11-08 at 14:56 +0100, Jakub Jelinek wrote: >> >> >> >> > On Sat, Nov 08, 2014 at 01:07:28PM +0100, Richard Biener wrote: >> >> >> >> > > To be constructive here - the above case is from within a >> >> >> >> > > GIMPLE_ASSIGN case label >> >> >> >> > > and thus I'd have expected >> >> >> >> > > >> >> >> >> > > case GIMPLE_ASSIGN: >> >> >> >> > > { >> >> >> >> > > gassign *a1 = as_a <gassign *> (s1); >> >> >> >> > > gassign *a2 = as_a <gassign *> (s2); >> >> >> >> > > lhs1 = gimple_assign_lhs (a1); >> >> >> >> > > lhs2 = gimple_assign_lhs (a2); >> >> >> >> > > if (TREE_CODE (lhs1) != SSA_NAME >> >> >> >> > > && TREE_CODE (lhs2) != SSA_NAME) >> >> >> >> > > return (operand_equal_p (lhs1, lhs2, 0) >> >> >> >> > > && gimple_operand_equal_value_p >> >> >> >> > > (gimple_assign_rhs1 (a1), >> >> >> >> > > >> >> >> >> > > gimple_assign_rhs1 (a2))); >> >> >> >> > > else if (TREE_CODE (lhs1) == SSA_NAME >> >> >> >> > > && TREE_CODE (lhs2) == SSA_NAME) >> >> >> >> > > return vn_valueize (lhs1) == vn_valueize (lhs2); >> >> >> >> > > return false; >> >> >> >> > > } >> >> >> >> > > >> >> >> >> > > instead. That's the kind of changes I have expected and have >> >> >> >> > > approved of. >> >> >> >> > >> >> >> >> > But even that looks like just adding extra work for all >> >> >> >> > developers, with no >> >> >> >> > gain. You only have to add extra code and extra temporaries, in >> >> >> >> > switches >> >> >> >> > typically also have to add {} because of the temporaries and thus >> >> >> >> > extra >> >> >> >> > indentation level, and it doesn't simplify anything in the code. >> >> >> >> >> >> >> >> The branch attempts to use the C++ typesystem to capture information >> >> >> >> about the kinds of gimple statement we expect, both: >> >> >> >> (A) so that the compiler can detect type errors, and >> >> >> >> (B) as a comprehension aid to the human reader of the code >> >> >> >> >> >> >> >> The ideal here is when function params and struct field can be >> >> >> >> strengthened from "gimple" to a subclass ptr. This captures the >> >> >> >> knowledge that every use of a function or within a struct has a >> >> >> >> given >> >> >> >> gimple code. >> >> >> > >> >> >> > I just don't like all the as_a/is_a stuff enforced everywhere, >> >> >> > it means more typing, more temporaries, more indentation. >> >> >> > So, as I view it, instead of the checks being done cheaply (yes, I >> >> >> > think >> >> >> > the gimple checking as we have right now is very cheap) under the >> >> >> > hood by the accessors (gimple_assign_{lhs,rhs1} etc.), those changes >> >> >> > put the burden on the developers, who has to check that manually >> >> >> > through >> >> >> > the as_a/is_a stuff everywhere, more typing and uglier syntax. >> >> >> > I just don't see that as a step forward, instead a huge step >> >> >> > backwards. >> >> >> > But perhaps I'm alone with this. >> >> >> > Can you e.g. compare the size of - lines in your patchset combined, >> >> >> > and >> >> >> > size of + lines in your patchset? As in, if your changes lead to >> >> >> > less >> >> >> > typing or more. >> >> >> >> >> >> I see two ways out here. One is to add overloads to all the functions >> >> >> taking the special types like >> >> >> >> >> >> tree >> >> >> gimple_assign_rhs1 (gimple *); >> >> >> >> >> >> or simply add >> >> >> >> >> >> gassign *operator ()(gimple *g) { return as_a <gassign *> (g); } >> >> >> >> >> >> into a gimple-compat.h header which you include in places that >> >> >> are not converted "nicely". >> >> > >> >> > Thanks for the suggestions. >> >> > >> >> > Am I missing something, or is the gimple-compat.h idea above not valid C >> >> > ++? >> >> > >> >> > Note that "gimple" is still a typedef to >> >> > gimple_statement_base * >> >> > (as noted before, the gimple -> gimple * change would break everyone >> >> > else's patches, so we talked about that as a followup patch for early >> >> > stage3). >> >> > >> >> > Given that, if I try to create an "operator ()" outside of a class, I >> >> > get this error: >> >> > >> >> > ‘gassign* operator()(gimple)’ must be a nonstatic member function >> >> > >> >> > which is emitted from cp/decl.c's grok_op_properties: >> >> > /* An operator function must either be a non-static member >> >> > function >> >> > or have at least one parameter of a class, a reference to a >> >> > class, >> >> > an enumeration, or a reference to an enumeration. 13.4.0.6 */ >> >> > >> >> > I tried making it a member function of gimple_statement_base, but that >> >> > doesn't work either: we want a conversion >> >> > from a gimple_statement_base * to a gassign *, not >> >> > from a gimple_statement_base to a gassign *. >> >> > >> >> > Is there some syntactic trick here that I'm missing? Sorry if I'm being >> >> > dumb (I can imagine there's a way of doing it by making "gimple" become >> >> > some kind of wrapped ptr class, but that way lies madness, surely). >> >> >> >> Hmm. >> >> >> >> struct assign; >> >> struct base { >> >> operator assign *() const { return (assign *)this; } >> >> }; >> >> struct assign : base { >> >> }; >> >> >> >> void foo (assign *); >> >> void bar (base *b) >> >> { >> >> foo (b); >> >> } >> >> >> >> doesn't work, but >> >> >> >> void bar (base &b) >> >> { >> >> foo (b); >> >> } >> >> >> >> does. Indeed C++ doesn't seem to provide what is necessary >> >> for the compat trick :( >> >> >> >> So the gimple-compat.h header would need to provide >> >> additional overloads for the affected functions like >> >> >> >> inline tree >> >> gimple_assign_rhs1 (gimple *g) >> >> { >> >> return gimple_assign_rhs1 (as_a <gassign *> (g)); >> >> } >> >> >> >> that would work for me as well. >> >> >> >> >> Both avoid manually making the compiler happy (which the >> >> >> explicit as_a<> stuff is! It doesn't add any "checking" - it's >> >> >> just placing the as_a<> at the callers and thus make the >> >> >> runtine ICE fire there). >> >> >> >> >> >> As much as I don't like "global" conversion operators I don't >> >> >> like adding overloads to all of the accessor functions even more. >> >> > >> >> > (nods) >> >> > >> >> > Some other options: >> >> > >> >> > Option 3: only convert the "easy" accessors: the ones I already did in >> >> > the /89 patch kit, as reviewed by Jeff, and rebased by me recently, >> >> > which is this 92-patch kit: >> >> > "[gimple-classes, committed 00/92] Initial slew of commits": >> >> > https://gcc.gnu.org/ml/gcc-patches/2014-10/msg02791.html >> >> > Doing so converts about half of the gimple_foo_ accessors to taking a >> >> > gfoo *, giving a mixture of GIMPLE_CHECK vs subclass use. I believe >> >> > the quality of those patches was higher than the later ones on the >> >> > branch: I was doing the places that didn't require the invasive/verbose >> >> > changes seen in the later patches. Shelve the remaining ~80 >> >> > increasingly ugly patches, starting a new branch to contain just the >> >> > good ones. >> > >> > I've created a branch "dmalcolm/gimple-classes-v2-option-3" >> > https://gcc.gnu.org/git/?p=gcc.git;a=shortlog;h=refs/heads/gimple-classes-v2-option-3 >> > >> > which takes the work reviewed by Jeff and the most trivial of the merger >> > followup work, throwing away the ~80 unloved followup patches on >> > dmalcolm/gimple-classes. >> > >> > I've merged from yesterday's trunk r217593 into that new branch, >> > resolving conflicts. >> > >> > I did this in two parts: the basic merger as >> > bd7fe714158f0c600caa05be7d744fd9139b8afb >> > resolving conflicts, with a followup patch to fixup new code from trunk >> > that used accessors that on the branch required a gimple subclass. >> > >> > Attached is that 2nd part of the merger. >> > >> > Successfully bootstrapped and regrtested on x86_64-unknown-linux-gnu; >> > same regrtest results as a control bootstrap of trunk's r217593. >> > >> > I appreciate Jakub and others have concerns about the overall approach. >> > I'm not sure which of option 2 (gimple-compat.h), option 3 (this one), >> > option 4 (just convert fields and non-accessor params), or defer to gcc >> > 6 is the best one, but I'm sleep-deprived and wanted to submit this >> > before the stage1 deadline. >> > >> > The other commits on this pruned branch that haven't been reviewed yet >> > are: >> > >> > [gimple-classes, committed 88/92] Preparatory work before subclass >> > renaming >> > https://gcc.gnu.org/ml/gcc-patches/2014-10/msg02820.html >> >> Ok. >> >> > [gimple-classes, committed 89/92] Eliminate subclass typedefs from >> > coretypes.h >> > https://gcc.gnu.org/ml/gcc-patches/2014-10/msg02838.html >> >> Ok. >> >> > [gimple-classes, committed 90/92] Automated renaming of gimple >> > subclasses >> > https://gcc.gnu.org/ml/gcc-patches/2014-10/msg02828.html >> >> Ok. >> >> > [gimple-classes, committed 91/92] Remove out-of-date references to >> > typedefs] >> > https://gcc.gnu.org/ml/gcc-patches/2014-10/msg02874.html >> >> Ok. >> >> > [gimple-classes, committed 92/92] Update gimple.texi class hierarchy >> > diagram >> > https://gcc.gnu.org/ml/gcc-patches/2014-10/msg02818.html >> >> Ok. >> >> > [gimple-classes] Merge trunk r216157-r216746 into branch >> > https://gcc.gnu.org/ml/gcc-patches/2014-10/msg02982.html >> >> Ok. > > Thanks. You said "Ok" to the various patches I pinged, but I don't > think you commented on the patch that was attached to the email. > > Is that one OK? It's: > https://gcc.gnu.org/ml/gcc-patches/2014-11/msg01935.html > in the archives.
Yes, that one is ok as well. > I believe that's the only unreviewed patch on the branch > "dmalcolm/gimple-classes-v2-option-3": > https://gcc.gnu.org/git/?p=gcc.git;a=shortlog;h=refs/heads/gimple-classes-v2-option-3 > > Assuming that's OK, I want to merge that branch to trunk in the next day > or so. Fine with me. >> > Also, presumably if this were merged, it would require a followup with >> > the gimple to gimple * fixup you wanted? (which we talked about doing as >> > an early stage3 thing IIRC [1]). >> >> Yeah, that would be nice (to remind people - this is about getting rid >> of const_gimple and thus avoids introducing tons of new const_ >> for all the subclasses). > > FWIW I got rid of all of those typedefs in the patches above (89/92 in > particular); the subclasses on the branch are already using explicit > ptrs, so it's more about consistency between base class ptrs and > subclass ptrs, to avoid: > > gimple stmt; > gphi *phi; > gcall *call_stmt; > > in favor of: > gimple *stmt; /* <-- note this one */ > gphi *phi; > gcall *call_stmt; right. > I'd already done that for the subclasses on the branch, and the diff > between the branch and trunk is relatively sane. > > By contrast, doing the gimple -> gimple * fixup will generate a huge > diff, so that's something to do after merging the branch. > I'll post the patch here later this week (or a link to it, it's likely > to be too big even compressed for the ML). Thanks, Richard. > Dave > >> Thanks, >> Richard. >> >> > Thanks >> > Dave >> > [1] e.g. https://gcc.gnu.org/ml/gcc-patches/2014-10/msg01536.html >> > >> > >> >> > Option 4: don't convert any accessors, but instead focus on fields of >> >> > structs (e.g. "call_stmt" within a cgraph_edge), and on params of other >> >> > functions (e.g. phi-manipulation code). That way we'd avoid the >> >> > inconsistency of some accessors using GIMPLE_CHECK and some using >> >> > subclasses - all would continue to consistently use GIMPLE_CHECK, but >> >> > there would be some extra type-checking and self-documentation of the >> >> > expected statement kinds in the code. >> >> > >> >> > >> >> > >> >> > FWIW, option 3 is my preferred approach (I've already done the bulk of >> >> > the work and it's already been reviewed; it would need an update merger >> >> > from trunk, and there's the big gimple to gimple * fixup you wanted). >> >> >> >> Works for me as well. The compat solution looks somewhat appealing >> >> as we can then incrementally fix up things rather than requiring to >> >> mass-convert everything. >> >> >> >> Thanks, >> >> Richard. >> >> >> >> >> Whether you enable them generally or just for selected files >> >> >> via a gimple-compat.h will be up to you (but I'd rather get >> >> >> rid of them at some point). >> >> >> >> >> >> Note this allows seamless transform of "random" functions >> >> >> taking a gimple now but really only expecting a single kind. >> >> >> >> >> >> Note that we don't absolutely have to rush this all in for GCC 5. >> >> >> Being the very first for GCC 6 stage1 is another possibility. >> >> >> We just should get it right. >> >> > >> >> > Thanks >> >> > Dave >> >> > >> > > >
