120 lines
3.9 KiB
C++
120 lines
3.9 KiB
C++
//=- WebAssemblySetP2AlignOperands.cpp - Set alignments on loads and stores -=//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// \brief This file sets the p2align operands on load and store instructions.
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///
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//===----------------------------------------------------------------------===//
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#include "WebAssembly.h"
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#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
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#include "WebAssemblyMachineFunctionInfo.h"
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#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
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#include "llvm/CodeGen/MachineMemOperand.h"
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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#define DEBUG_TYPE "wasm-set-p2align-operands"
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namespace {
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class WebAssemblySetP2AlignOperands final : public MachineFunctionPass {
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public:
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static char ID; // Pass identification, replacement for typeid
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WebAssemblySetP2AlignOperands() : MachineFunctionPass(ID) {}
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StringRef getPassName() const override {
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return "WebAssembly Set p2align Operands";
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}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.setPreservesCFG();
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AU.addPreserved<MachineBlockFrequencyInfo>();
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AU.addPreservedID(MachineDominatorsID);
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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bool runOnMachineFunction(MachineFunction &MF) override;
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};
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} // end anonymous namespace
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char WebAssemblySetP2AlignOperands::ID = 0;
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FunctionPass *llvm::createWebAssemblySetP2AlignOperands() {
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return new WebAssemblySetP2AlignOperands();
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}
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static void RewriteP2Align(MachineInstr &MI, unsigned OperandNo) {
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assert(MI.getOperand(OperandNo).getImm() == 0 &&
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"ISel should set p2align operands to 0");
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assert(MI.hasOneMemOperand() &&
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"Load and store instructions have exactly one mem operand");
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assert((*MI.memoperands_begin())->getSize() ==
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(UINT64_C(1)
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<< WebAssembly::GetDefaultP2Align(MI.getOpcode())) &&
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"Default p2align value should be natural");
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assert(MI.getDesc().OpInfo[OperandNo].OperandType ==
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WebAssembly::OPERAND_P2ALIGN &&
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"Load and store instructions should have a p2align operand");
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uint64_t P2Align = Log2_64((*MI.memoperands_begin())->getAlignment());
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// WebAssembly does not currently support supernatural alignment.
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P2Align = std::min(
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P2Align, uint64_t(WebAssembly::GetDefaultP2Align(MI.getOpcode())));
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MI.getOperand(OperandNo).setImm(P2Align);
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}
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bool WebAssemblySetP2AlignOperands::runOnMachineFunction(MachineFunction &MF) {
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DEBUG({
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dbgs() << "********** Set p2align Operands **********\n"
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<< "********** Function: " << MF.getName() << '\n';
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});
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bool Changed = false;
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for (auto &MBB : MF) {
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for (auto &MI : MBB) {
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switch (MI.getOpcode()) {
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case WebAssembly::LOAD_I32:
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case WebAssembly::LOAD_I64:
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case WebAssembly::LOAD_F32:
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case WebAssembly::LOAD_F64:
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case WebAssembly::LOAD8_S_I32:
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case WebAssembly::LOAD8_U_I32:
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case WebAssembly::LOAD16_S_I32:
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case WebAssembly::LOAD16_U_I32:
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case WebAssembly::LOAD8_S_I64:
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case WebAssembly::LOAD8_U_I64:
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case WebAssembly::LOAD16_S_I64:
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case WebAssembly::LOAD16_U_I64:
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case WebAssembly::LOAD32_S_I64:
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case WebAssembly::LOAD32_U_I64:
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RewriteP2Align(MI, WebAssembly::LoadP2AlignOperandNo);
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break;
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case WebAssembly::STORE_I32:
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case WebAssembly::STORE_I64:
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case WebAssembly::STORE_F32:
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case WebAssembly::STORE_F64:
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case WebAssembly::STORE8_I32:
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case WebAssembly::STORE16_I32:
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case WebAssembly::STORE8_I64:
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case WebAssembly::STORE16_I64:
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case WebAssembly::STORE32_I64:
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RewriteP2Align(MI, WebAssembly::StoreP2AlignOperandNo);
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break;
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default:
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break;
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}
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}
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}
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return Changed;
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}
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