| //=- WebAssemblySetP2AlignOperands.cpp - Set alignments on loads and stores -=// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| /// |
| /// \file |
| /// This file sets the p2align operands on load and store instructions. |
| /// |
| //===----------------------------------------------------------------------===// |
| |
| #include "MCTargetDesc/WebAssemblyMCTargetDesc.h" |
| #include "WebAssembly.h" |
| #include "WebAssemblyInstrInfo.h" |
| #include "WebAssemblyMachineFunctionInfo.h" |
| #include "llvm/CodeGen/MachineBlockFrequencyInfo.h" |
| #include "llvm/CodeGen/MachineMemOperand.h" |
| #include "llvm/CodeGen/Passes.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/raw_ostream.h" |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "wasm-set-p2align-operands" |
| |
| namespace { |
| class WebAssemblySetP2AlignOperands final : public MachineFunctionPass { |
| public: |
| static char ID; // Pass identification, replacement for typeid |
| WebAssemblySetP2AlignOperands() : MachineFunctionPass(ID) {} |
| |
| StringRef getPassName() const override { |
| return "WebAssembly Set p2align Operands"; |
| } |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override { |
| AU.setPreservesCFG(); |
| AU.addPreserved<MachineBlockFrequencyInfo>(); |
| AU.addPreservedID(MachineDominatorsID); |
| MachineFunctionPass::getAnalysisUsage(AU); |
| } |
| |
| bool runOnMachineFunction(MachineFunction &MF) override; |
| }; |
| } // end anonymous namespace |
| |
| char WebAssemblySetP2AlignOperands::ID = 0; |
| INITIALIZE_PASS(WebAssemblySetP2AlignOperands, DEBUG_TYPE, |
| "Set the p2align operands for WebAssembly loads and stores", |
| false, false) |
| |
| FunctionPass *llvm::createWebAssemblySetP2AlignOperands() { |
| return new WebAssemblySetP2AlignOperands(); |
| } |
| |
| static void rewriteP2Align(MachineInstr &MI, unsigned OperandNo) { |
| assert(MI.getOperand(OperandNo).getImm() == 0 && |
| "ISel should set p2align operands to 0"); |
| assert(MI.hasOneMemOperand() && |
| "Load and store instructions have exactly one mem operand"); |
| assert((*MI.memoperands_begin())->getSize() == |
| (UINT64_C(1) << WebAssembly::GetDefaultP2Align(MI.getOpcode())) && |
| "Default p2align value should be natural"); |
| assert(MI.getDesc().OpInfo[OperandNo].OperandType == |
| WebAssembly::OPERAND_P2ALIGN && |
| "Load and store instructions should have a p2align operand"); |
| uint64_t P2Align = Log2((*MI.memoperands_begin())->getAlign()); |
| |
| // WebAssembly does not currently support supernatural alignment. |
| P2Align = std::min(P2Align, |
| uint64_t(WebAssembly::GetDefaultP2Align(MI.getOpcode()))); |
| |
| MI.getOperand(OperandNo).setImm(P2Align); |
| } |
| |
| bool WebAssemblySetP2AlignOperands::runOnMachineFunction(MachineFunction &MF) { |
| LLVM_DEBUG({ |
| dbgs() << "********** Set p2align Operands **********\n" |
| << "********** Function: " << MF.getName() << '\n'; |
| }); |
| |
| bool Changed = false; |
| |
| for (auto &MBB : MF) { |
| for (auto &MI : MBB) { |
| int16_t P2AlignOpNum = WebAssembly::getNamedOperandIdx( |
| MI.getOpcode(), WebAssembly::OpName::p2align); |
| if (P2AlignOpNum != -1) { |
| rewriteP2Align(MI, P2AlignOpNum); |
| Changed = true; |
| } |
| } |
| } |
| |
| return Changed; |
| } |