From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 68DADC88E5C for ; Wed, 16 Sep 2026 13:28:45 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1x6pg6-0001li-ER; Wed, 16 Sep 2026 09:27:58 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x6pfx-0001kX-3z for qemu-devel@nongnu.org; Wed, 16 Sep 2026 09:27:50 -0400 Received: from rev.ng ([94.130.142.21]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x6pft-0003sS-Tu for qemu-devel@nongnu.org; Wed, 16 Sep 2026 09:27:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=rev.ng; s=dkim; h=Content-Transfer-Encoding:Content-Type:MIME-Version:References: In-Reply-To:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive:List-Unsubscribe:List-Unsubscribe-Post: List-Help; bh=1eXrWsY9QzEZjAtgFp+SDzuMxOY85sHaE+WCiHXYFPA=; b=AskOddfwJR2Qvoe OH6YzdFJxaAdzjN8kz743e1Pa+FJvSNRt9l1QI4Pt54ErJLO1oIW9kFy1KosZF7gKDyzzgMemCSsO NV0MFmTiQnao3sas4VEIGoecUdGuebKqA7iFQRjIElacFQHKaRuORxQst4HB51A2nP/IlQQYVulmR 6Y=; Date: Wed, 16 Sep 2026 14:42:39 +0200 To: Anton Johansson Cc: qemu-devel@nongnu.org, brian.cain@oss.qualcomm.com, pierrick.bouvier@oss.qualcomm.com, philmd@mailo.com Subject: Re: [PATCH v2 22/50] helper-to-tcg: Introduce PrepareForTcgPass Message-ID: <20260916144239.4350a6ec@spawn> In-Reply-To: <20260730031025.12926-23-anjo@rev.ng> References: <20260730031025.12926-1-anjo@rev.ng> <20260730031025.12926-23-anjo@rev.ng> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=94.130.142.21; envelope-from=ale@rev.ng; helo=rev.ng X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Alessandro Di Federico From: Alessandro Di Federico via qemu development Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, 30 Jul 2026 05:09:56 +0200 Anton Johansson wrote: > Adds a new pass over the LLVM module which runs post-optimization with > the end-goal of: > > * Culling functions which aren't worth translating; > * Canonicalizing the IR to something closer to TCG, and; When you "canonicalize" for a backend, you're doing more "instruction selection" than canonicalization. The goal of canonicalization is to bring the IR in the most standard, frontend- and backend-agnostic representation you can. I'd talk about a form of instruction selection. > * Extracting information which may be useful in the backend pass. > > The bulk of IR transformations occur in the canonicalization phase, with > a handful occuring later in the packend. This commits sets up a new LLVM packend > pass over the IR module and runs it from the pipeline. > > Signed-off-by: Anton Johansson > --- > .../helper-to-tcg/include/CmdLineOptions.hpp | 2 ++ > .../include/PrepareForTcgPass.hpp | 27 +++++++++++++++++++ > subprojects/helper-to-tcg/meson.build | 1 + > subprojects/helper-to-tcg/src/Pipeline.cpp | 24 +++++++++++++++++ > .../PrepareForTcgPass/PrepareForTcgPass.cpp | 25 +++++++++++++++++ > 5 files changed, 79 insertions(+) > create mode 100644 subprojects/helper-to-tcg/include/PrepareForTcgPass.hpp > create mode 100644 subprojects/helper-to-tcg/src/PrepareForTcgPass/PrepareForTcgPass.cpp > > diff --git a/subprojects/helper-to-tcg/include/CmdLineOptions.hpp b/subprojects/helper-to-tcg/include/CmdLineOptions.hpp > index ca1cb59835..bfdd3ebe41 100644 > --- a/subprojects/helper-to-tcg/include/CmdLineOptions.hpp > +++ b/subprojects/helper-to-tcg/include/CmdLineOptions.hpp > @@ -23,3 +23,5 @@ > extern llvm::cl::list InputFiles; > // Options for PrepareForOptPass > extern llvm::cl::opt TranslateAllHelpers; > +// Options for PrepareForTcgPass > +extern llvm::cl::opt TcgGlobalMappingsName; > diff --git a/subprojects/helper-to-tcg/include/PrepareForTcgPass.hpp b/subprojects/helper-to-tcg/include/PrepareForTcgPass.hpp > new file mode 100644 > index 0000000000..90bc9402cb > --- /dev/null > +++ b/subprojects/helper-to-tcg/include/PrepareForTcgPass.hpp > @@ -0,0 +1,27 @@ > +// > +// Copyright(c) 2026 rev.ng Labs Srl. All Rights Reserved. > +// > +// This program is free software; you can redistribute it and/or modify > +// it under the terms of the GNU General Public License as published by > +// the Free Software Foundation; either version 2 of the License, or > +// (at your option) any later version. > +// > +// This program is distributed in the hope that it will be useful, > +// but WITHOUT ANY WARRANTY; without even the implied warranty of > +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > +// GNU General Public License for more details. > +// > +// You should have received a copy of the GNU General Public License > +// along with this program; if not, see . > +// > + > +#pragma once > + > +#include > + > +class PrepareForTcgPass : public llvm::PassInfoMixin { > +public: > + PrepareForTcgPass() {} > + llvm::PreservedAnalyses run(llvm::Module &M, > + llvm::ModuleAnalysisManager &MAM); > +}; > diff --git a/subprojects/helper-to-tcg/meson.build b/subprojects/helper-to-tcg/meson.build > index b3a3de6297..c2926652f3 100644 > --- a/subprojects/helper-to-tcg/meson.build > +++ b/subprojects/helper-to-tcg/meson.build > @@ -44,6 +44,7 @@ sources = [ > 'src/Pipeline.cpp', > 'src/PrepareForOptPass/PrepareForOptPass.cpp', > 'src/PseudoInst.cpp', > + 'src/PrepareForTcgPass/PrepareForTcgPass.cpp', > ] > > clang = bindir / 'clang' > diff --git a/subprojects/helper-to-tcg/src/Pipeline.cpp b/subprojects/helper-to-tcg/src/Pipeline.cpp > index 571276de24..6058718a9c 100644 > --- a/subprojects/helper-to-tcg/src/Pipeline.cpp > +++ b/subprojects/helper-to-tcg/src/Pipeline.cpp > @@ -18,6 +18,7 @@ > #include "CmdLineOptions.hpp" > #include "LlvmCompat.hpp" > #include "PrepareForOptPass.hpp" > +#include "PrepareForTcgPass.hpp" > > #if LLVM_VERSION_MAJOR == 15 > #include > @@ -32,6 +33,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -43,6 +45,7 @@ > #include > #include > #include > +#include > #include > > #define DEBUG_TYPE "pipeline" > @@ -70,6 +73,13 @@ cl::opt TranslateAllHelpers( > "translate-all-helpers", cl::init(false), > cl::desc("Translate all functions starting with helper_*"), cl::cat(Cat)); > > +// Options for PrepareForTcgPass > +cl::opt TcgGlobalMappingsName( > + "tcg-global-mappings", > + cl::desc(" + "into a struct to TCG globals>"), > + cl::Required, cl::cat(Cat)); > + I'd drop this and go by convention (i.e., just assume the name) + documentation. If you think this is useful for debugging purposes, at least give it a default so we don't need to specify the parameter in the regular invocation. If you keep this, introduce it in the first commit using it TcgGlobalMappingsName. > // Define a TargetTransformInfo (TTI) subclass, this allows for overriding > // common per-llvm-target information expected by other LLVM passes, such > // as the width of the largest scalar/vector registers. Needed for consistent > @@ -214,5 +224,19 @@ int main(int argc, char **argv) { > MPM.addPass( > PB.buildModuleOptimizationPipeline(compat::OptimizationLevel::Oz, {})); > > + // > + // Next, we run our final transformations, including removing phis and our > + // own instruction combining that prioritizes instructions that map more > + // easily to TCG. > + // > + > + MPM.addPass(PrepareForTcgPass()); > + MPM.addPass(VerifierPass()); > + { > + FunctionPassManager FPM; > + FPM.addPass(DCEPass()); > + MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM))); > + } > + > return 0; > } > diff --git a/subprojects/helper-to-tcg/src/PrepareForTcgPass/PrepareForTcgPass.cpp b/subprojects/helper-to-tcg/src/PrepareForTcgPass/PrepareForTcgPass.cpp > new file mode 100644 > index 0000000000..cea6573e41 > --- /dev/null > +++ b/subprojects/helper-to-tcg/src/PrepareForTcgPass/PrepareForTcgPass.cpp > @@ -0,0 +1,25 @@ > +// > +// Copyright(c) 2026 rev.ng Labs Srl. All Rights Reserved. > +// > +// This program is free software; you can redistribute it and/or modify > +// it under the terms of the GNU General Public License as published by > +// the Free Software Foundation; either version 2 of the License, or > +// (at your option) any later version. > +// > +// This program is distributed in the hope that it will be useful, > +// but WITHOUT ANY WARRANTY; without even the implied warranty of > +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > +// GNU General Public License for more details. > +// > +// You should have received a copy of the GNU General Public License > +// along with this program; if not, see . > +// > + > +#include "PrepareForTcgPass.hpp" > + > +using namespace llvm; > + > +PreservedAnalyses PrepareForTcgPass::run(Module &M, ModuleAnalysisManager &MAM) > +{ > + return PreservedAnalyses::none(); > +} > -- > 2.52.0 Reviewed-by: Alessandro Di Federico -- Alessandro Di Federico rev.ng Labs