LLVM  6.0.0svn
LeonPasses.cpp
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1 //===------ LeonPasses.cpp - Define passes specific to LEON ---------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "LeonPasses.h"
19 #include "llvm/IR/DiagnosticInfo.h"
20 #include "llvm/IR/LLVMContext.h"
22 using namespace llvm;
23 
25  : MachineFunctionPass(ID) {}
26 
27 //*****************************************************************************
28 //**** InsertNOPLoad pass
29 //*****************************************************************************
30 // This pass fixes the incorrectly working Load instructions that exists for
31 // some earlier versions of the LEON processor line. NOP instructions must
32 // be inserted after the load instruction to ensure that the Load instruction
33 // behaves as expected for these processors.
34 //
35 // This pass inserts a NOP after any LD or LDF instruction.
36 //
37 char InsertNOPLoad::ID = 0;
38 
40 
44  DebugLoc DL = DebugLoc();
45 
46  bool Modified = false;
47  for (auto MFI = MF.begin(), E = MF.end(); MFI != E; ++MFI) {
48  MachineBasicBlock &MBB = *MFI;
49  for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++MBBI) {
50  MachineInstr &MI = *MBBI;
51  unsigned Opcode = MI.getOpcode();
52  if (Opcode >= SP::LDDArr && Opcode <= SP::LDrr) {
53  MachineBasicBlock::iterator NMBBI = std::next(MBBI);
54  BuildMI(MBB, NMBBI, DL, TII.get(SP::NOP));
55  Modified = true;
56  }
57  }
58  }
59 
60  return Modified;
61 }
62 
63 
64 
65 //*****************************************************************************
66 //**** DetectRoundChange pass
67 //*****************************************************************************
68 // To prevent any explicit change of the default rounding mode, this pass
69 // detects any call of the fesetround function.
70 // A warning is generated to ensure the user knows this has happened.
71 //
72 // Detects an erratum in UT699 LEON 3 processor
73 
74 char DetectRoundChange::ID = 0;
75 
77 
80 
81  bool Modified = false;
82  for (auto MFI = MF.begin(), E = MF.end(); MFI != E; ++MFI) {
83  MachineBasicBlock &MBB = *MFI;
84  for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++MBBI) {
85  MachineInstr &MI = *MBBI;
86  unsigned Opcode = MI.getOpcode();
87  if (Opcode == SP::CALL && MI.getNumOperands() > 0) {
88  MachineOperand &MO = MI.getOperand(0);
89 
90  if (MO.isGlobal()) {
91  StringRef FuncName = MO.getGlobal()->getName();
92  if (FuncName.compare_lower("fesetround") == 0) {
93  errs() << "Error: You are using the detectroundchange "
94  "option to detect rounding changes that will "
95  "cause LEON errata. The only way to fix this "
96  "is to remove the call to fesetround from "
97  "the source code.\n";
98  }
99  }
100  }
101  }
102  }
103 
104  return Modified;
105 }
106 
107 //*****************************************************************************
108 //**** FixAllFDIVSQRT pass
109 //*****************************************************************************
110 // This pass fixes the incorrectly working FDIVx and FSQRTx instructions that
111 // exist for some earlier versions of the LEON processor line. Five NOP
112 // instructions need to be inserted after these instructions to ensure the
113 // correct result is placed in the destination registers before they are used.
114 //
115 // This pass implements two fixes:
116 // 1) fixing the FSQRTS and FSQRTD instructions.
117 // 2) fixing the FDIVS and FDIVD instructions.
118 //
119 // FSQRTS and FDIVS are converted to FDIVD and FSQRTD respectively earlier in
120 // the pipeline when this option is enabled, so this pass needs only to deal
121 // with the changes that still need implementing for the "double" versions
122 // of these instructions.
123 //
124 char FixAllFDIVSQRT::ID = 0;
125 
127 
131  DebugLoc DL = DebugLoc();
132 
133  bool Modified = false;
134  for (auto MFI = MF.begin(), E = MF.end(); MFI != E; ++MFI) {
135  MachineBasicBlock &MBB = *MFI;
136  for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++MBBI) {
137  MachineInstr &MI = *MBBI;
138  unsigned Opcode = MI.getOpcode();
139 
140  // Note: FDIVS and FSQRTS cannot be generated when this erratum fix is
141  // switched on so we don't need to check for them here. They will
142  // already have been converted to FSQRTD or FDIVD earlier in the
143  // pipeline.
144  if (Opcode == SP::FSQRTD || Opcode == SP::FDIVD) {
145  for (int InsertedCount = 0; InsertedCount < 5; InsertedCount++)
146  BuildMI(MBB, MBBI, DL, TII.get(SP::NOP));
147 
148  MachineBasicBlock::iterator NMBBI = std::next(MBBI);
149  for (int InsertedCount = 0; InsertedCount < 28; InsertedCount++)
150  BuildMI(MBB, NMBBI, DL, TII.get(SP::NOP));
151 
152  Modified = true;
153  }
154  }
155  }
156 
157  return Modified;
158 }
raw_ostream & errs()
This returns a reference to a raw_ostream for standard error.
DILocation * get() const
Get the underlying DILocation.
Definition: DebugLoc.cpp:22
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
static char ID
Definition: LeonPasses.h:76
static char ID
Definition: LeonPasses.h:48
A debug info location.
Definition: DebugLoc.h:34
const SparcInstrInfo * getInstrInfo() const override
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
const HexagonInstrInfo * TII
unsigned getNumOperands() const
Access to explicit operands of the instruction.
Definition: MachineInstr.h:293
unsigned getOpcode() const
Returns the opcode of this MachineInstr.
Definition: MachineInstr.h:290
bool runOnMachineFunction(MachineFunction &MF) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
Definition: LeonPasses.cpp:41
TargetInstrInfo - Interface to description of machine instruction set.
const SparcSubtarget * Subtarget
Definition: LeonPasses.h:27
MachineInstrBuilder BuildMI(MachineFunction &MF, const DebugLoc &DL, const MCInstrDesc &MCID)
Builder interface. Specify how to create the initial instruction itself.
const TargetSubtargetInfo & getSubtarget() const
getSubtarget - Return the subtarget for which this machine code is being compiled.
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
const GlobalValue * getGlobal() const
bool runOnMachineFunction(MachineFunction &MF) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
Definition: LeonPasses.cpp:128
LLVM_NODISCARD int compare_lower(StringRef RHS) const
compare_lower - Compare two strings, ignoring case.
Definition: StringRef.cpp:53
bool isGlobal() const
isGlobal - Tests if this is a MO_GlobalAddress operand.
MachineOperand class - Representation of each machine instruction operand.
Representation of each machine instruction.
Definition: MachineInstr.h:59
bool runOnMachineFunction(MachineFunction &MF) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
Definition: LeonPasses.cpp:78
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:220
IRTranslator LLVM IR MI
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
const MachineOperand & getOperand(unsigned i) const
Definition: MachineInstr.h:295