c5d240093b
Soon it will be disallowed to depend on MachineFunction state in the constructor. This was only being used to get the MachineRegisterInfo for an assert, which I'm not sure is necessarily worth it. I would think any missing defs would be caught by the verifier later instead.
111 lines
3.9 KiB
C++
111 lines
3.9 KiB
C++
//===-- WebAssemblyRegNumbering.cpp - Register Numbering ------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// This file implements a pass which assigns WebAssembly register
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/// numbers for CodeGen virtual registers.
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///
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//===----------------------------------------------------------------------===//
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#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
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#include "WebAssembly.h"
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#include "WebAssemblyMachineFunctionInfo.h"
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#include "WebAssemblySubtarget.h"
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#include "WebAssemblyUtilities.h"
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#include "llvm/ADT/SCCIterator.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineLoopInfo.h"
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#include "llvm/CodeGen/MachineRegisterInfo.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-reg-numbering"
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namespace {
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class WebAssemblyRegNumbering final : public MachineFunctionPass {
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StringRef getPassName() const override {
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return "WebAssembly Register Numbering";
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}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.setPreservesCFG();
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MachineFunctionPass::getAnalysisUsage(AU);
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}
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bool runOnMachineFunction(MachineFunction &MF) override;
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public:
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static char ID; // Pass identification, replacement for typeid
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WebAssemblyRegNumbering() : MachineFunctionPass(ID) {}
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};
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} // end anonymous namespace
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char WebAssemblyRegNumbering::ID = 0;
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INITIALIZE_PASS(WebAssemblyRegNumbering, DEBUG_TYPE,
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"Assigns WebAssembly register numbers for virtual registers",
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false, false)
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FunctionPass *llvm::createWebAssemblyRegNumbering() {
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return new WebAssemblyRegNumbering();
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}
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bool WebAssemblyRegNumbering::runOnMachineFunction(MachineFunction &MF) {
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LLVM_DEBUG(dbgs() << "********** Register Numbering **********\n"
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"********** Function: "
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<< MF.getName() << '\n');
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WebAssemblyFunctionInfo &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
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MachineRegisterInfo &MRI = MF.getRegInfo();
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MFI.initWARegs(MRI);
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// WebAssembly argument registers are in the same index space as local
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// variables. Assign the numbers for them first.
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MachineBasicBlock &EntryMBB = MF.front();
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for (MachineInstr &MI : EntryMBB) {
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if (!WebAssembly::isArgument(MI.getOpcode()))
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break;
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int64_t Imm = MI.getOperand(1).getImm();
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LLVM_DEBUG(dbgs() << "Arg VReg " << MI.getOperand(0).getReg()
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<< " -> WAReg " << Imm << "\n");
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MFI.setWAReg(MI.getOperand(0).getReg(), Imm);
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}
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// Then assign regular WebAssembly registers for all remaining used
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// virtual registers. TODO: Consider sorting the registers by frequency of
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// use, to maximize usage of small immediate fields.
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unsigned NumVRegs = MF.getRegInfo().getNumVirtRegs();
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unsigned NumStackRegs = 0;
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// Start the numbering for locals after the arg regs
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unsigned CurReg = MFI.getParams().size();
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for (unsigned VRegIdx = 0; VRegIdx < NumVRegs; ++VRegIdx) {
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unsigned VReg = Register::index2VirtReg(VRegIdx);
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// Skip unused registers.
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if (MRI.use_empty(VReg))
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continue;
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// Handle stackified registers.
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if (MFI.isVRegStackified(VReg)) {
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LLVM_DEBUG(dbgs() << "VReg " << VReg << " -> WAReg "
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<< (INT32_MIN | NumStackRegs) << "\n");
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MFI.setWAReg(VReg, INT32_MIN | NumStackRegs++);
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continue;
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}
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if (MFI.getWAReg(VReg) == WebAssemblyFunctionInfo::UnusedReg) {
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LLVM_DEBUG(dbgs() << "VReg " << VReg << " -> WAReg " << CurReg << "\n");
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MFI.setWAReg(VReg, CurReg++);
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}
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}
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return true;
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}
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