From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 2002:a6b:9710:: with SMTP id z16-v6mr6051429iod.85.1535381181553; Mon, 27 Aug 2018 07:46:21 -0700 (PDT) X-Received: by 2002:aca:de07:: with SMTP id v7-v6mr297262oig.5.1535381181245; Mon, 27 Aug 2018 07:46:21 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!feeder.eternal-september.org!news.uzoreto.com!feeder.usenetexpress.com!feeder-in1.iad1.usenetexpress.com!border1.nntp.dca1.giganews.com!nntp.giganews.com!g24-v6no3534056iti.0!news-out.google.com!c63-v6ni4060ith.0!nntp.google.com!g24-v6no3534051iti.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Mon, 27 Aug 2018 07:46:20 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=2a02:c7d:3c35:b000:325a:3aff:fe0f:37a5; posting-account=L2-UcQkAAAAfd_BqbeNHs3XeM0jTXloS NNTP-Posting-Host: 2a02:c7d:3c35:b000:325a:3aff:fe0f:37a5 References: <309225242.556906218.575482.laguest-archeia.com@nntp.aioe.org> <2145221813.556924687.162377.laguest-archeia.com@nntp.aioe.org> <3892c779-2924-405c-b88d-19389fc5ba3e@googlegroups.com> <1ceec6d8-c5c4-49b1-9808-a3580bba3f8e@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <64d7d54b-40fd-4090-b772-1402cce09dc4@googlegroups.com> Subject: Re: Studying and Maintaining GNAT, Is There Any Interest in a New Group? From: Lucretia Injection-Date: Mon, 27 Aug 2018 14:46:21 +0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Xref: reader02.eternal-september.org comp.lang.ada:54267 Date: 2018-08-27T07:46:20-07:00 List-Id: On Monday, 27 August 2018 03:38:32 UTC+1, Dan'l Miller wrote: > > There is no quibbling, I was pointing out his error in what he thought = was what. >=20 > No, I was the one at the risk of quibbling by pointing out that GNAT has = this weird not-truly-front-end, not-truly-back-end 3rd layer called GIGI tr= ee transducer to convert between the two (i.e., Ada versus C/C++) semantic = trees, where the Ada semantic tree is in the Ada-language-source-code front= -end and the C/C++ semantic tree is in the C-language-source-code back-end = of GNAT. >=20 > My main point is: I suspect that (except for brand new revisions of the = Ada _LRM_) most bugs are not in the GNAT true-=E2=80=A2front=E2=80=A2-end i= n Ada-language source-code nor in the GNAT true-=E2=80=A2back=E2=80=A2-end = in C-language source-code shared with the rest of GCC. I suspect that the = vast majority of lingering compiler bugs in GNAT have their root cause in l= ess-than-perfect tree-transduction from Ada semantic tree to C/C++-GENERIC/= GIMPLE semantic tree, due in turn to having blinders on or tunnel vision, n= ot looking at enough context in the large. You don't seem to understand how compilers or GCC is structured. There is n= o weird 3rd layer. Compilers use multiple intermediate representations starting with an asbstr= act syntax tree, the passes take in the AST and modify it or create a new t= ree/IR until it gets to the point where code generation can take place. Tha= t's essentially it Source Language -> Front-end -> AST -> IR -> IR -> .. -> IR -> Codegen -> A= ssembly code -> Assembler -> Machine code -> Linker -> Executable =20 > > > semantically-adorned AST (in Ada-language source code) into GENERIC/G= IMPLE C/C++ semantic tree > > > (in C-language=20 > >=20 > > What are you going on about? >=20 > My sentences are precisely worded to say what needs to be said without fu= rther rebuttal by me, stating the same thing again. If something specific = is unclear, please narrow your request for information. Why use 1 word when 50 will do, right? =20 > > That's exactly the point, it would be a completely different design, a = completely different compiler, > > hence nothing from GCC/GNAT. >=20 > Yes, eliminating GNAT's need for a tree transducer between 2 semantic tre= es (one for Ada, the other for C/C++) is the =E2=80=9Cradical new design=E2= =80=9D of a next-gen Ada compiler. We agree there. No, see above, you always need that, because that's what compilers do. All = compilers have language neutral IR's, your front end has to convert from so= urce language to that IR, whether it's GCC's GENERIC/GIMPLE or LLVM or Firm= . =20 > I seem to recall an unrelenting general pox on all historical-Ada houses = as the overall gist from you. Nope, I said that there is literally no point in trying to reimplement the = same software which people didn't like at the time, repeating history, i.e.= the source stored as an IR in a database. People didn't want it then, they= ain't gonna want it now because getting source in and out of a DB is a pai= n, yes I know that's what happens with source control, but that's the way i= t is. > Unlike all other replies along all branches of all threads deriving from = the OP, I actually started doing what the OP sought technologically: start= discussing the actual internal design of GNAT for the purpose of how to un= derstand it for the purpose of how to maintain it. (I am not sure that we = need a new group/forum; what is wrong with discussing the design/internals = of GNAT here on c.l.a?) https://gcc.gnu.org/onlinedocs/gccint/index.html <<- the book you need to r= ead to understand the internals of GCC, it's not an easy or nice read.