/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/lib/Target/WebAssembly/WebAssemblyRegNumbering.cpp
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1 | | //===-- WebAssemblyRegNumbering.cpp - Register Numbering ------------------===// |
2 | | // |
3 | | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | | // See https://llvm.org/LICENSE.txt for license information. |
5 | | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | | // |
7 | | //===----------------------------------------------------------------------===// |
8 | | /// |
9 | | /// \file |
10 | | /// This file implements a pass which assigns WebAssembly register |
11 | | /// numbers for CodeGen virtual registers. |
12 | | /// |
13 | | //===----------------------------------------------------------------------===// |
14 | | |
15 | | #include "MCTargetDesc/WebAssemblyMCTargetDesc.h" |
16 | | #include "WebAssembly.h" |
17 | | #include "WebAssemblyMachineFunctionInfo.h" |
18 | | #include "WebAssemblySubtarget.h" |
19 | | #include "WebAssemblyUtilities.h" |
20 | | #include "llvm/ADT/SCCIterator.h" |
21 | | #include "llvm/CodeGen/MachineFrameInfo.h" |
22 | | #include "llvm/CodeGen/MachineFunction.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" |
29 | | using namespace llvm; |
30 | | |
31 | | #define DEBUG_TYPE "wasm-reg-numbering" |
32 | | |
33 | | namespace { |
34 | | class WebAssemblyRegNumbering final : public MachineFunctionPass { |
35 | 4.87k | StringRef getPassName() const override { |
36 | 4.87k | return "WebAssembly Register Numbering"; |
37 | 4.87k | } |
38 | | |
39 | 425 | void getAnalysisUsage(AnalysisUsage &AU) const override { |
40 | 425 | AU.setPreservesCFG(); |
41 | 425 | MachineFunctionPass::getAnalysisUsage(AU); |
42 | 425 | } |
43 | | |
44 | | bool runOnMachineFunction(MachineFunction &MF) override; |
45 | | |
46 | | public: |
47 | | static char ID; // Pass identification, replacement for typeid |
48 | 426 | WebAssemblyRegNumbering() : MachineFunctionPass(ID) {} |
49 | | }; |
50 | | } // end anonymous namespace |
51 | | |
52 | | char WebAssemblyRegNumbering::ID = 0; |
53 | | INITIALIZE_PASS(WebAssemblyRegNumbering, DEBUG_TYPE, |
54 | | "Assigns WebAssembly register numbers for virtual registers", |
55 | | false, false) |
56 | | |
57 | 426 | FunctionPass *llvm::createWebAssemblyRegNumbering() { |
58 | 426 | return new WebAssemblyRegNumbering(); |
59 | 426 | } |
60 | | |
61 | 4.45k | bool WebAssemblyRegNumbering::runOnMachineFunction(MachineFunction &MF) { |
62 | 4.45k | LLVM_DEBUG(dbgs() << "********** Register Numbering **********\n" |
63 | 4.45k | "********** Function: " |
64 | 4.45k | << MF.getName() << '\n'); |
65 | 4.45k | |
66 | 4.45k | WebAssemblyFunctionInfo &MFI = *MF.getInfo<WebAssemblyFunctionInfo>(); |
67 | 4.45k | MachineRegisterInfo &MRI = MF.getRegInfo(); |
68 | 4.45k | |
69 | 4.45k | MFI.initWARegs(); |
70 | 4.45k | |
71 | 4.45k | // WebAssembly argument registers are in the same index space as local |
72 | 4.45k | // variables. Assign the numbers for them first. |
73 | 4.45k | MachineBasicBlock &EntryMBB = MF.front(); |
74 | 13.9k | for (MachineInstr &MI : EntryMBB) { |
75 | 13.9k | if (!WebAssembly::isArgument(MI.getOpcode())) |
76 | 4.44k | break; |
77 | 9.52k | |
78 | 9.52k | int64_t Imm = MI.getOperand(1).getImm(); |
79 | 9.52k | LLVM_DEBUG(dbgs() << "Arg VReg " << MI.getOperand(0).getReg() |
80 | 9.52k | << " -> WAReg " << Imm << "\n"); |
81 | 9.52k | MFI.setWAReg(MI.getOperand(0).getReg(), Imm); |
82 | 9.52k | } |
83 | 4.45k | |
84 | 4.45k | // Then assign regular WebAssembly registers for all remaining used |
85 | 4.45k | // virtual registers. TODO: Consider sorting the registers by frequency of |
86 | 4.45k | // use, to maximize usage of small immediate fields. |
87 | 4.45k | unsigned NumVRegs = MF.getRegInfo().getNumVirtRegs(); |
88 | 4.45k | unsigned NumStackRegs = 0; |
89 | 4.45k | // Start the numbering for locals after the arg regs |
90 | 4.45k | unsigned CurReg = MFI.getParams().size(); |
91 | 73.1k | for (unsigned VRegIdx = 0; VRegIdx < NumVRegs; ++VRegIdx68.6k ) { |
92 | 68.6k | unsigned VReg = TargetRegisterInfo::index2VirtReg(VRegIdx); |
93 | 68.6k | // Skip unused registers. |
94 | 68.6k | if (MRI.use_empty(VReg)) |
95 | 26.9k | continue; |
96 | 41.7k | // Handle stackified registers. |
97 | 41.7k | if (MFI.isVRegStackified(VReg)) { |
98 | 31.5k | LLVM_DEBUG(dbgs() << "VReg " << VReg << " -> WAReg " |
99 | 31.5k | << (INT32_MIN | NumStackRegs) << "\n"); |
100 | 31.5k | MFI.setWAReg(VReg, INT32_MIN | NumStackRegs++); |
101 | 31.5k | continue; |
102 | 31.5k | } |
103 | 10.1k | if (MFI.getWAReg(VReg) == WebAssemblyFunctionInfo::UnusedReg) { |
104 | 642 | LLVM_DEBUG(dbgs() << "VReg " << VReg << " -> WAReg " << CurReg << "\n"); |
105 | 642 | MFI.setWAReg(VReg, CurReg++); |
106 | 642 | } |
107 | 10.1k | } |
108 | 4.45k | |
109 | 4.45k | return true; |
110 | 4.45k | } |