LLVM  16.0.0git
LeonPasses.cpp
Go to the documentation of this file.
1 //===------ LeonPasses.cpp - Define passes specific to LEON ---------------===//
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 //
10 //===----------------------------------------------------------------------===//
11 
12 #include "LeonPasses.h"
13 #include "SparcSubtarget.h"
19 
20 using namespace llvm;
21 
24 
25 //*****************************************************************************
26 //**** InsertNOPLoad pass
27 //*****************************************************************************
28 // This pass fixes the incorrectly working Load instructions that exists for
29 // some earlier versions of the LEON processor line. NOP instructions must
30 // be inserted after the load instruction to ensure that the Load instruction
31 // behaves as expected for these processors.
32 //
33 // This pass inserts a NOP after any LD or LDF instruction.
34 //
35 char InsertNOPLoad::ID = 0;
36 
38 
42  DebugLoc DL = DebugLoc();
43 
44  bool Modified = false;
45  for (MachineBasicBlock &MBB : MF) {
46  for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++MBBI) {
47  MachineInstr &MI = *MBBI;
48  unsigned Opcode = MI.getOpcode();
49  if (Opcode >= SP::LDDArr && Opcode <= SP::LDrr) {
50  MachineBasicBlock::iterator NMBBI = std::next(MBBI);
51  BuildMI(MBB, NMBBI, DL, TII.get(SP::NOP));
52  Modified = true;
53  }
54  }
55  }
56 
57  return Modified;
58 }
59 
60 
61 
62 //*****************************************************************************
63 //**** DetectRoundChange pass
64 //*****************************************************************************
65 // To prevent any explicit change of the default rounding mode, this pass
66 // detects any call of the fesetround function.
67 // A warning is generated to ensure the user knows this has happened.
68 //
69 // Detects an erratum in UT699 LEON 3 processor
70 
71 char DetectRoundChange::ID = 0;
72 
74 
77 
78  bool Modified = false;
79  for (MachineBasicBlock &MBB : MF) {
80  for (MachineInstr &MI : MBB) {
81  unsigned Opcode = MI.getOpcode();
82  if (Opcode == SP::CALL && MI.getNumOperands() > 0) {
83  MachineOperand &MO = MI.getOperand(0);
84 
85  if (MO.isGlobal()) {
86  StringRef FuncName = MO.getGlobal()->getName();
87  if (FuncName.compare_insensitive("fesetround") == 0) {
88  errs() << "Error: You are using the detectroundchange "
89  "option to detect rounding changes that will "
90  "cause LEON errata. The only way to fix this "
91  "is to remove the call to fesetround from "
92  "the source code.\n";
93  }
94  }
95  }
96  }
97  }
98 
99  return Modified;
100 }
101 
102 //*****************************************************************************
103 //**** FixAllFDIVSQRT pass
104 //*****************************************************************************
105 // This pass fixes the incorrectly working FDIVx and FSQRTx instructions that
106 // exist for some earlier versions of the LEON processor line. Five NOP
107 // instructions need to be inserted after these instructions to ensure the
108 // correct result is placed in the destination registers before they are used.
109 //
110 // This pass implements two fixes:
111 // 1) fixing the FSQRTS and FSQRTD instructions.
112 // 2) fixing the FDIVS and FDIVD instructions.
113 //
114 // FSQRTS and FDIVS are converted to FDIVD and FSQRTD respectively earlier in
115 // the pipeline when this option is enabled, so this pass needs only to deal
116 // with the changes that still need implementing for the "double" versions
117 // of these instructions.
118 //
119 char FixAllFDIVSQRT::ID = 0;
120 
122 
126  DebugLoc DL = DebugLoc();
127 
128  bool Modified = false;
129  for (MachineBasicBlock &MBB : MF) {
130  for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++MBBI) {
131  MachineInstr &MI = *MBBI;
132  unsigned Opcode = MI.getOpcode();
133 
134  // Note: FDIVS and FSQRTS cannot be generated when this erratum fix is
135  // switched on so we don't need to check for them here. They will
136  // already have been converted to FSQRTD or FDIVD earlier in the
137  // pipeline.
138  if (Opcode == SP::FSQRTD || Opcode == SP::FDIVD) {
139  for (int InsertedCount = 0; InsertedCount < 5; InsertedCount++)
140  BuildMI(MBB, MBBI, DL, TII.get(SP::NOP));
141 
142  MachineBasicBlock::iterator NMBBI = std::next(MBBI);
143  for (int InsertedCount = 0; InsertedCount < 28; InsertedCount++)
144  BuildMI(MBB, NMBBI, DL, TII.get(SP::NOP));
145 
146  Modified = true;
147  }
148  }
149  }
150 
151  return Modified;
152 }
MI
IRTranslator LLVM IR MI
Definition: IRTranslator.cpp:109
MachineInstr.h
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
llvm::LEONMachineFunctionPass::LEONMachineFunctionPass
LEONMachineFunctionPass(char &ID)
Definition: LeonPasses.cpp:22
llvm::MachineOperand::getGlobal
const GlobalValue * getGlobal() const
Definition: MachineOperand.h:572
llvm::DetectRoundChange::DetectRoundChange
DetectRoundChange()
Definition: LeonPasses.cpp:73
llvm::MachineFunctionPass
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
Definition: MachineFunctionPass.h:30
llvm::InsertNOPLoad::InsertNOPLoad
InsertNOPLoad()
Definition: LeonPasses.cpp:37
MachineBasicBlock.h
llvm::AArch64ISD::CALL
@ CALL
Definition: AArch64ISelLowering.h:53
llvm::DetectRoundChange::ID
static char ID
Definition: LeonPasses.h:57
llvm::errs
raw_fd_ostream & errs()
This returns a reference to a raw_ostream for standard error.
Definition: raw_ostream.cpp:891
llvm::InsertNOPLoad::ID
static char ID
Definition: LeonPasses.h:42
llvm::TargetInstrInfo
TargetInstrInfo - Interface to description of machine instruction set.
Definition: TargetInstrInfo.h:98
E
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
llvm::FixAllFDIVSQRT::FixAllFDIVSQRT
FixAllFDIVSQRT()
Definition: LeonPasses.cpp:121
TII
const HexagonInstrInfo * TII
Definition: HexagonCopyToCombine.cpp:125
llvm::MachineOperand
MachineOperand class - Representation of each machine instruction operand.
Definition: MachineOperand.h:48
LoopDeletionResult::Modified
@ Modified
llvm::SparcSubtarget
Definition: SparcSubtarget.h:31
llvm::CallingConv::ID
unsigned ID
LLVM IR allows to use arbitrary numbers as calling convention identifiers.
Definition: CallingConv.h:24
llvm::MachineBasicBlock
Definition: MachineBasicBlock.h:94
SparcSubtarget.h
llvm::DetectRoundChange::runOnMachineFunction
bool runOnMachineFunction(MachineFunction &MF) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
Definition: LeonPasses.cpp:75
llvm::MachineFunction::getSubtarget
const TargetSubtargetInfo & getSubtarget() const
getSubtarget - Return the subtarget for which this machine code is being compiled.
Definition: MachineFunction.h:660
llvm::MachineInstr
Representation of each machine instruction.
Definition: MachineInstr.h:66
llvm::FixAllFDIVSQRT::ID
static char ID
Definition: LeonPasses.h:70
llvm::SparcSubtarget::getInstrInfo
const SparcInstrInfo * getInstrInfo() const override
Definition: SparcSubtarget.h:64
llvm::LEONMachineFunctionPass::Subtarget
const SparcSubtarget * Subtarget
Definition: LeonPasses.h:23
llvm::MachineFunction
Definition: MachineFunction.h:257
llvm::StringRef
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
MBBI
MachineBasicBlock MachineBasicBlock::iterator MBBI
Definition: AArch64SLSHardening.cpp:75
DL
MachineBasicBlock MachineBasicBlock::iterator DebugLoc DL
Definition: AArch64SLSHardening.cpp:76
llvm::Value::getName
StringRef getName() const
Return a constant reference to the value's name.
Definition: Value.cpp:308
MBB
MachineBasicBlock & MBB
Definition: AArch64SLSHardening.cpp:74
llvm::InsertNOPLoad::runOnMachineFunction
bool runOnMachineFunction(MachineFunction &MF) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
Definition: LeonPasses.cpp:39
llvm::BuildMI
MachineInstrBuilder BuildMI(MachineFunction &MF, const MIMetadata &MIMD, const MCInstrDesc &MCID)
Builder interface. Specify how to create the initial instruction itself.
Definition: MachineInstrBuilder.h:357
llvm::MachineBasicBlock::begin
iterator begin()
Definition: MachineBasicBlock.h:309
MachineInstrBuilder.h
llvm::StringRef::compare_insensitive
int compare_insensitive(StringRef RHS) const
Compare two strings, ignoring case.
Definition: StringRef.cpp:37
llvm::FixAllFDIVSQRT::runOnMachineFunction
bool runOnMachineFunction(MachineFunction &MF) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
Definition: LeonPasses.cpp:123
llvm::DebugLoc
A debug info location.
Definition: DebugLoc.h:33
LeonPasses.h
raw_ostream.h
MachineFunction.h
llvm::MachineInstrBundleIterator< MachineInstr >
llvm::MachineBasicBlock::end
iterator end()
Definition: MachineBasicBlock.h:311
llvm::MachineOperand::isGlobal
bool isGlobal() const
isGlobal - Tests if this is a MO_GlobalAddress operand.
Definition: MachineOperand.h:338
llvm::LEONMachineFunctionPass
Definition: LeonPasses.h:20