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/MachineFrameInfo.h"
23 #include "llvm/CodeGen/MachineInstrBuilder.h"
24 #include "llvm/CodeGen/MachineLoopInfo.h"
25 #include "llvm/CodeGen/MachineRegisterInfo.h"
26 #include "llvm/CodeGen/Passes.h"
27 #include "llvm/Support/Debug.h"
28 #include "llvm/Support/raw_ostream.h"
31 #define DEBUG_TYPE "wasm-reg-numbering"
34 class WebAssemblyRegNumbering final : public MachineFunctionPass {
35 const char *getPassName() const override {
36 return "WebAssembly Register Numbering";
39 void getAnalysisUsage(AnalysisUsage &AU) const override {
41 MachineFunctionPass::getAnalysisUsage(AU);
44 bool runOnMachineFunction(MachineFunction &MF) override;
47 static char ID; // Pass identification, replacement for typeid
48 WebAssemblyRegNumbering() : MachineFunctionPass(ID) {}
50 } // end anonymous namespace
52 char WebAssemblyRegNumbering::ID = 0;
53 FunctionPass *llvm::createWebAssemblyRegNumbering() {
54 return new WebAssemblyRegNumbering();
57 bool WebAssemblyRegNumbering::runOnMachineFunction(MachineFunction &MF) {
58 DEBUG(dbgs() << "********** Register Numbering **********\n"
59 "********** Function: "
60 << MF.getName() << '\n');
62 WebAssemblyFunctionInfo &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
63 MachineRegisterInfo &MRI = MF.getRegInfo();
64 const MachineFrameInfo &FrameInfo = *MF.getFrameInfo();
68 // WebAssembly argument registers are in the same index space as local
69 // variables. Assign the numbers for them first.
70 MachineBasicBlock &EntryMBB = MF.front();
71 for (MachineInstr &MI : EntryMBB) {
72 switch (MI.getOpcode()) {
73 case WebAssembly::ARGUMENT_I32:
74 case WebAssembly::ARGUMENT_I64:
75 case WebAssembly::ARGUMENT_F32:
76 case WebAssembly::ARGUMENT_F64:
77 MFI.setWAReg(MI.getOperand(0).getReg(), MI.getOperand(1).getImm());
84 // Then assign regular WebAssembly registers for all remaining used
86 unsigned NumArgRegs = MFI.getParams().size();
87 unsigned NumVRegs = MF.getRegInfo().getNumVirtRegs();
88 unsigned NumStackRegs = 0;
90 for (unsigned VRegIdx = 0; VRegIdx < NumVRegs; ++VRegIdx) {
91 unsigned VReg = TargetRegisterInfo::index2VirtReg(VRegIdx);
92 // Handle stackified registers.
93 if (MFI.isVRegStackified(VReg)) {
94 MFI.setWAReg(VReg, INT32_MIN | NumStackRegs++);
97 // Skip unused registers.
98 if (MRI.use_empty(VReg))
100 if (MFI.getWAReg(VReg) == WebAssemblyFunctionInfo::UnusedReg)
101 MFI.setWAReg(VReg, NumArgRegs + CurReg++);
103 // Allocate locals for used physical registers
104 if (FrameInfo.getStackSize() > 0)
105 MFI.addPReg(WebAssembly::SP32, CurReg++);