From patchwork Thu Nov 21 01:49:31 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Johansson X-Patchwork-Id: 13881548 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 lists.gnu.org (lists.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 CAC57D743FC for ; Thu, 21 Nov 2024 01:49:23 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tDwI0-0001gi-QQ; Wed, 20 Nov 2024 20:47:24 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tDwHy-0001fj-9O for qemu-devel@nongnu.org; Wed, 20 Nov 2024 20:47:22 -0500 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 1tDwHw-0004Zz-BC for qemu-devel@nongnu.org; Wed, 20 Nov 2024 20:47:22 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=rev.ng; s=dkim; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type: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=MxJZlENkdmUchmgfGBkk9kv4bmuX6oYA3cdwhm+q3rc=; b=hq2y0jcrCKtVUJ6 jmSO+GqWFQJR8gyvoJMP6GPMgxeJTNZDSLuRxR7IS4Uz+6VVuiN6dc5uJ3RjsA8BL1LQvKyleaOtR WocUTOxAPXSFW9MaBiobApnG1GxuZHXaQheOOyLaoWVchROCGQbOmzJsJPbDrj3H2lrn7s41G/il3 YQ=; To: qemu-devel@nongnu.org Cc: ale@rev.ng, ltaylorsimpson@gmail.com, bcain@quicinc.com, richard.henderson@linaro.org, philmd@linaro.org, alex.bennee@linaro.org Subject: [RFC PATCH v1 27/43] helper-to-tcg: PrepareForTcgPass, identity map trivial expressions Date: Thu, 21 Nov 2024 02:49:31 +0100 Message-ID: <20241121014947.18666-28-anjo@rev.ng> In-Reply-To: <20241121014947.18666-1-anjo@rev.ng> References: <20241121014947.18666-1-anjo@rev.ng> MIME-Version: 1.0 Received-SPF: pass client-ip=94.130.142.21; envelope-from=anjo@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, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, 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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-to: Anton Johansson X-Patchwork-Original-From: Anton Johansson via From: Anton Johansson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Transformation of the IR, identity mapping trivial expressions which would amount to nothing more than a move when emitted as TCG, but is required in LLVM IR to not break the IR. Trivial expressions are mapped to a @IdentityMap pseudo instruction allowing them to be dealt with in a uniform manner down the line. Signed-off-by: Anton Johansson --- subprojects/helper-to-tcg/meson.build | 1 + .../passes/PrepareForTcgPass/IdentityMap.cpp | 80 +++++++++++++++++++ .../passes/PrepareForTcgPass/IdentityMap.h | 39 +++++++++ .../PrepareForTcgPass/PrepareForTcgPass.cpp | 4 + 4 files changed, 124 insertions(+) create mode 100644 subprojects/helper-to-tcg/passes/PrepareForTcgPass/IdentityMap.cpp create mode 100644 subprojects/helper-to-tcg/passes/PrepareForTcgPass/IdentityMap.h diff --git a/subprojects/helper-to-tcg/meson.build b/subprojects/helper-to-tcg/meson.build index 50bb926f49..09caa74c63 100644 --- a/subprojects/helper-to-tcg/meson.build +++ b/subprojects/helper-to-tcg/meson.build @@ -49,6 +49,7 @@ sources = [ 'passes/PrepareForTcgPass/PrepareForTcgPass.cpp', 'passes/PrepareForTcgPass/TransformGEPs.cpp', 'passes/PrepareForTcgPass/CanonicalizeIR.cpp', + 'passes/PrepareForTcgPass/IdentityMap.cpp', ] clang = bindir / 'clang' diff --git a/subprojects/helper-to-tcg/passes/PrepareForTcgPass/IdentityMap.cpp b/subprojects/helper-to-tcg/passes/PrepareForTcgPass/IdentityMap.cpp new file mode 100644 index 0000000000..b173aeba9c --- /dev/null +++ b/subprojects/helper-to-tcg/passes/PrepareForTcgPass/IdentityMap.cpp @@ -0,0 +1,80 @@ +// +// Copyright(c) 2024 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 "IdentityMap.h" +#include +#include "backend/TcgType.h" +#include +#include +#include +#include +#include + +using namespace llvm; + +void identityMap(Module &M, Function &F) +{ + SmallVector InstToErase; + + for (auto &I : instructions(F)) { + auto *ZExt = dyn_cast(&I); + if (ZExt) { + auto *IntTy0 = + dyn_cast(ZExt->getOperand(0)->getType()); + auto *IntTy1 = dyn_cast(ZExt->getType()); + if (IntTy0 and IntTy1) { + uint32_t LlvmSize0 = IntTy0->getBitWidth(); + uint32_t LlvmSize1 = IntTy1->getBitWidth(); + + if (LlvmSize0 == 1) { + auto *ICmp = dyn_cast(ZExt->getOperand(0)); + if (ICmp) { + auto *ICmpOp = ICmp->getOperand(0); + LlvmSize0 = + cast(ICmpOp->getType())->getBitWidth(); + } + } + + uint32_t TcgSize0 = llvmToTcgSize(LlvmSize0); + uint32_t TcgSize1 = llvmToTcgSize(LlvmSize1); + + if (TcgSize0 == TcgSize1) { + FunctionCallee Fn = + pseudoInstFunction(M, IdentityMap, IntTy1, {IntTy0}); + IRBuilder<> Builder(&I); + CallInst *Call = + Builder.CreateCall(Fn, {ZExt->getOperand(0)}); + ZExt->replaceAllUsesWith(Call); + InstToErase.push_back(&I); + } + } + } else if (isa(&I)) { + auto *IntTy0 = dyn_cast(I.getOperand(0)->getType()); + auto *IntTy1 = dyn_cast(I.getType()); + FunctionCallee Fn = + pseudoInstFunction(M, IdentityMap, IntTy1, {IntTy0}); + IRBuilder<> Builder(&I); + CallInst *Call = Builder.CreateCall(Fn, {I.getOperand(0)}); + I.replaceAllUsesWith(Call); + InstToErase.push_back(&I); + } + } + + for (auto *I : InstToErase) { + I->eraseFromParent(); + } +} diff --git a/subprojects/helper-to-tcg/passes/PrepareForTcgPass/IdentityMap.h b/subprojects/helper-to-tcg/passes/PrepareForTcgPass/IdentityMap.h new file mode 100644 index 0000000000..b0c938c25d --- /dev/null +++ b/subprojects/helper-to-tcg/passes/PrepareForTcgPass/IdentityMap.h @@ -0,0 +1,39 @@ +// +// Copyright(c) 2024 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 +#include + +// +// Transformation of the IR, taking what would become trivial unary operations +// and maps them to a single @IdentityMap pseudo instruction. +// +// To motivate further, in order to produce nice IR on the other end, generally +// the operands of these trivial expressions needs to be forwarded and treated +// as the destination value (identity mapped). However, directly removing these +// instructions will result in broken LLVM IR (consider zext i8, i32 where both +// the source and destination would map to TCGv_i32). +// +// Moreover, handling these identity mapped values in an adhoc way quickly +// becomes cumbersome and spreads throughout the codebase. Therefore, +// introducing @IdentityMap allows code further down the pipeline to ignore the +// source of the identity map. +// + +void identityMap(llvm::Module &M, llvm::Function &F); diff --git a/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForTcgPass.cpp b/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForTcgPass.cpp index 7fdbc2a0c9..3e4713d837 100644 --- a/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForTcgPass.cpp +++ b/subprojects/helper-to-tcg/passes/PrepareForTcgPass/PrepareForTcgPass.cpp @@ -17,6 +17,7 @@ #include "CanonicalizeIR.h" #include +#include "IdentityMap.h" #include #include "TransformGEPs.h" #include @@ -126,5 +127,8 @@ PreservedAnalyses PrepareForTcgPass::run(Module &M, ModuleAnalysisManager &MAM) transformGEPs(M, F, ResultTcgGlobalMap); } canonicalizeIR(M); + for (Function &F : M) { + identityMap(M, F); + } return PreservedAnalyses::none(); }