1 //===-- WebAssemblyRegNumbering.cpp - Register Numbering ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
11 /// \brief This file implements a pass which assigns WebAssembly register
12 /// numbers for CodeGen virtual registers.
14 //===----------------------------------------------------------------------===//
16 #include "WebAssembly.h"
17 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
18 #include "WebAssemblyMachineFunctionInfo.h"
19 #include "WebAssemblySubtarget.h"
20 #include "llvm/ADT/SCCIterator.h"
21 #include "llvm/CodeGen/MachineFunction.h"
22 #include "llvm/CodeGen/MachineInstrBuilder.h"
23 #include "llvm/CodeGen/MachineLoopInfo.h"
24 #include "llvm/CodeGen/MachineRegisterInfo.h"
25 #include "llvm/CodeGen/Passes.h"
26 #include "llvm/Support/Debug.h"
27 #include "llvm/Support/raw_ostream.h"
30 #define DEBUG_TYPE "wasm-reg-numbering"
33 class WebAssemblyRegNumbering final : public MachineFunctionPass {
34 const char *getPassName() const override {
35 return "WebAssembly Register Numbering";
38 void getAnalysisUsage(AnalysisUsage &AU) const override {
40 MachineFunctionPass::getAnalysisUsage(AU);
43 bool runOnMachineFunction(MachineFunction &MF) override;
46 static char ID; // Pass identification, replacement for typeid
47 WebAssemblyRegNumbering() : MachineFunctionPass(ID) {}
49 } // end anonymous namespace
51 char WebAssemblyRegNumbering::ID = 0;
52 FunctionPass *llvm::createWebAssemblyRegNumbering() {
53 return new WebAssemblyRegNumbering();
56 bool WebAssemblyRegNumbering::runOnMachineFunction(MachineFunction &MF) {
57 DEBUG(dbgs() << "********** Register Numbering **********\n"
58 "********** Function: "
59 << MF.getName() << '\n');
61 WebAssemblyFunctionInfo &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
62 MachineRegisterInfo &MRI = MF.getRegInfo();
66 // WebAssembly argument registers are in the same index space as local
67 // variables. Assign the numbers for them first.
68 MachineBasicBlock &EntryMBB = MF.front();
69 for (MachineInstr &MI : EntryMBB) {
70 switch (MI.getOpcode()) {
71 case WebAssembly::ARGUMENT_I32:
72 case WebAssembly::ARGUMENT_I64:
73 case WebAssembly::ARGUMENT_F32:
74 case WebAssembly::ARGUMENT_F64:
75 MFI.setWAReg(MI.getOperand(0).getReg(), MI.getOperand(1).getImm());
82 // Then assign regular WebAssembly registers for all remaining used
84 unsigned NumArgRegs = MFI.getParams().size();
85 unsigned NumVRegs = MF.getRegInfo().getNumVirtRegs();
86 unsigned NumStackRegs = 0;
88 for (unsigned VRegIdx = 0; VRegIdx < NumVRegs; ++VRegIdx) {
89 unsigned VReg = TargetRegisterInfo::index2VirtReg(VRegIdx);
90 // Handle stackified registers.
91 if (MFI.isVRegStackified(VReg)) {
92 MFI.setWAReg(VReg, INT32_MIN | NumStackRegs++);
95 // Skip unused registers.
96 if (MRI.use_empty(VReg))
98 if (MFI.getWAReg(VReg) == WebAssemblyFunctionInfo::UnusedReg)
99 MFI.setWAReg(VReg, NumArgRegs + CurReg++);