11d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross/* 21d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * Copyright 2015, The Android Open Source Project 31d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * 41d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * Licensed under the Apache License, Version 2.0 (the "License"); 51d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * you may not use this file except in compliance with the License. 61d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * You may obtain a copy of the License at 71d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * 81d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * http://www.apache.org/licenses/LICENSE-2.0 91d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * 101d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * Unless required by applicable law or agreed to in writing, software 111d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * distributed under the License is distributed on an "AS IS" BASIS, 121d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 131d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * See the License for the specific language governing permissions and 141d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * limitations under the License. 151d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross */ 161d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 171d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross#include "bcc/Renderscript/RSTransforms.h" 1823c2bfe96698091f2886d1959435d8949f76c46bDavid Gross#include "bcc/Renderscript/RSUtils.h" 191d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 201d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross#include <llvm/IR/Function.h> 211d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross#include <llvm/IR/Instructions.h> 221d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross#include <llvm/IR/Metadata.h> 231d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross#include <llvm/IR/Module.h> 241d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross#include <llvm/IR/Type.h> 251d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross#include <llvm/Pass.h> 261d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 271d93a190e62ec1588b4724ca8759216b2d0b76d7David Grossnamespace { 281d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 291d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross/* 301d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * RSInvariantPass - This pass looks for Loads that access 311d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * RsExpandKernelDriverInfo instances (which should never be written by 321d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * a script, only by the driver) and marks them "invariant.load". 331d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * 341d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * There should be only two sources of Loads from such instances: 351d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * - An instance can appear as an argument of type 361d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * "RsExpandKernelDriverInfoPfx*" passed to a .expand function by 371d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * the driver. 381d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * - An instance can appear as an argument of type 391d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * "rs_kernel_context_t*" passed to an API query function by the 401d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * user. 411d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * Only the compiler-generated .expand functions and the API query 421d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * functions can see the fields of RsExpandKernelDriverInfo -- 431d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * rs_kernel_context_t is opaque to user code, so there cannot be any 441d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * Loads from it in user code. 451d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * 461d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * This pass should be run 471d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * - after foreachexp, so that it can see the Loads generated within 481d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * .expand functions 491d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * - before inlining, so that it can recognize API query function 501d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * arguments. 511d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * 521d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * WARNINGS: 531d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * - If user code or APIs can modify RsExpandKernelDriverInfo 541d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * instances, this pass MAY ALLOW ILLEGAL OPTIMIZATION. 551d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * - If this pass runs at a different time, it may be ineffective 561d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * (fail to mark some or all eligible Loads, and thereby cost 571d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * performance). 581d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * - If the names of the data types change, this pass may be 591d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * ineffective. 601d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * - If the patterns by which fields are loaded from 611d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * RsExpandKernelDriverInfo instances change, this pass may be 621d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * ineffective. 631d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross */ 641d93a190e62ec1588b4724ca8759216b2d0b76d7David Grossclass RSInvariantPass : public llvm::FunctionPass { 651d93a190e62ec1588b4724ca8759216b2d0b76d7David Grosspublic: 661d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross static char ID; 671d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 681d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross RSInvariantPass() : FunctionPass(ID), EmptyMDNode(nullptr) { } 691d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 701d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross virtual bool doInitialization(llvm::Module &M) { 711d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross EmptyMDNode = llvm::MDNode::get(M.getContext(), llvm::None); 721d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross return true; 731d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 741d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 751d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross virtual bool runOnFunction(llvm::Function &F) { 761d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross bool Changed = false; 771d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 781d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross for (llvm::Value &Arg : F.args()) { 791d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross const llvm::Type *ArgType = Arg.getType(); 801d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross if (ArgType->isPointerTy()) { 811d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross const llvm::Type *ArgPtrDomainType = ArgType->getPointerElementType(); 82e8b9f0607d59e991d984302d790b8b16e3623cc3Pirama Arumuga Nainar if (auto ArgPtrDomainStructType = llvm::dyn_cast<llvm::StructType>(ArgPtrDomainType)) { 83150eef4097c996e14b50b7f58184265385c44713Pirama Arumuga Nainar if (!ArgPtrDomainStructType->isLiteral()) { 8423c2bfe96698091f2886d1959435d8949f76c46bDavid Gross const llvm::StringRef StructName = getUnsuffixedStructName(ArgPtrDomainStructType); 85e8b9f0607d59e991d984302d790b8b16e3623cc3Pirama Arumuga Nainar if (StructName.equals("struct.rs_kernel_context_t") || StructName.equals("RsExpandKernelDriverInfoPfx")) { 86e8b9f0607d59e991d984302d790b8b16e3623cc3Pirama Arumuga Nainar Changed |= markInvariantUserLoads(&Arg); 87e8b9f0607d59e991d984302d790b8b16e3623cc3Pirama Arumuga Nainar } 881d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 891d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 901d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 911d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 921d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 931d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross return Changed; 941d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 951d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 961d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross virtual const char *getPassName() const { 971d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross return "Renderscript Invariant Load Annotation"; 981d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 991d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 1001d93a190e62ec1588b4724ca8759216b2d0b76d7David Grossprivate: 1011d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 1021d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross /* 1031d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * Follow def->use chains rooted at Value through calculations 1041d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * "based on" Value (see the "based on" definition at 1051d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * http://llvm.org/docs/LangRef.html#pointer-aliasing-rules). If a 1061d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * chain reaches the pointer operand of a Load, mark that Load as 1071d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * "invariant.load" -- i.e., it accesses memory which does not 1081d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * change. 1091d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross */ 1101d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross bool markInvariantUserLoads(llvm::Value *Value) { 1111d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross bool Changed = false; 1121d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross for (llvm::Use &Use : Value->uses()) { 1131d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross llvm::Instruction *Inst = llvm::cast<llvm::Instruction>(Use.getUser()); 1141d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 1151d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross /* 1161d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * We only examine a small set of opcodes here, because these 1171d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * are the opcodes that currently appear in the patterns of 1181d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * interest (foreachexp-generated code, and 1191d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * rsGet*(rs_kernel_context_t*) APIs). Other opcodes could be 1201d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross * added if necessary. 1211d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross */ 1221d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross if (auto BitCast = llvm::dyn_cast<llvm::BitCastInst>(Inst)) { 1231d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross Changed |= markInvariantUserLoads(BitCast); 1241d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } else if (auto GetElementPtr = llvm::dyn_cast<llvm::GetElementPtrInst>(Inst)) { 1251d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross if (Use.get() == GetElementPtr->getPointerOperand()) 1261d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross Changed |= markInvariantUserLoads(GetElementPtr); 1271d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } else if (auto Load = llvm::dyn_cast<llvm::LoadInst>(Inst)) { 1281d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross if (Use.get() == Load->getPointerOperand()) { 1291d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross Load->setMetadata("invariant.load", EmptyMDNode); 1301d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross Changed = true; 1311d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 1321d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 1331d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 1341d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross return Changed; 1351d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross } 1361d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 1371d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross // Pointer to empty metadata node used for "invariant.load" marking. 1381d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross llvm::MDNode *EmptyMDNode; 1391d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross}; // end RSInvariantPass 1401d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 1411d93a190e62ec1588b4724ca8759216b2d0b76d7David Grosschar RSInvariantPass::ID = 0; 1421d93a190e62ec1588b4724ca8759216b2d0b76d7David Grossllvm::RegisterPass<RSInvariantPass> X("rsinvariant", "RS Invariant Load Pass"); 1431d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 1441d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross} // end anonymous namespace 1451d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 1461d93a190e62ec1588b4724ca8759216b2d0b76d7David Grossnamespace bcc { 1471d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 1481d93a190e62ec1588b4724ca8759216b2d0b76d7David Grossllvm::FunctionPass * 1491d93a190e62ec1588b4724ca8759216b2d0b76d7David GrosscreateRSInvariantPass() { 1501d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross return new RSInvariantPass(); 1511d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross} 1521d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross 1531d93a190e62ec1588b4724ca8759216b2d0b76d7David Gross} // end namespace bcc 154