LLVM: lib/Target/X86/X86SpeculativeExecutionSideEffectSuppression.cpp Source File (original) (raw)
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26using namespace llvm;
27
28#define DEBUG_TYPE "x86-seses"
29
30STATISTIC(NumLFENCEsInserted, "Number of lfence instructions inserted");
31
33 "x86-seses-enable-without-lvi-cfi",
34 cl::desc("Force enable speculative execution side effect suppression. "
35 "(Note: User must pass -mlvi-cfi in order to mitigate indirect "
36 "branches and returns.)"),
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40 "x86-seses-one-lfence-per-bb",
42 "Omit all lfences other than the first to be placed in a basic block."),
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46 "x86-seses-only-lfence-non-const",
47 cl::desc("Only lfence before groups of terminators where at least one "
48 "branch instruction has an input to the addressing mode that is a "
49 "register other than %rip."),
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54 cl::desc("Omit all lfences before branch instructions."),
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57namespace {
58
59class X86SpeculativeExecutionSideEffectSuppression
61public:
63
64 static char ID;
65 StringRef getPassName() const override {
66 return "X86 Speculative Execution Side Effect Suppression";
67 }
68
69 bool runOnMachineFunction(MachineFunction &MF) override;
70};
71}
72
73char X86SpeculativeExecutionSideEffectSuppression::ID = 0;
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83 if (MO.isReg() && X86::RIP != MO.getReg())
84 return false;
85 return true;
86}
87
88bool X86SpeculativeExecutionSideEffectSuppression::runOnMachineFunction(
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92 const X86Subtarget &Subtarget = MF.getSubtarget();
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98 !(Subtarget.useLVILoadHardening() && OptLevel == CodeGenOptLevel::None) &&
99 !Subtarget.useSpeculativeExecutionSideEffectSuppression())
100 return false;
101
103 << " **********\n");
106 for (MachineBasicBlock &MBB : MF) {
107 MachineInstr *FirstTerminator = nullptr;
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110 bool PrevInstIsLFENCE = false;
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113 if (MI.getOpcode() == X86::LFENCE) {
114 PrevInstIsLFENCE = true;
115 continue;
116 }
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122 if (MI.mayLoadOrStore() && .isTerminator()) {
123 if (!PrevInstIsLFENCE) {
125 NumLFENCEsInserted++;
127 }
129 break;
130 }
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144 if (MI.isTerminator() && FirstTerminator == nullptr)
145 FirstTerminator = &MI;
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151 PrevInstIsLFENCE = false;
152 continue;
153 }
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158 PrevInstIsLFENCE = false;
159 continue;
160 }
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163 if (!PrevInstIsLFENCE) {
164 assert(FirstTerminator && "Unknown terminator instruction");
166 NumLFENCEsInserted++;
168 }
169 break;
170 }
171 }
172
174}
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177 return new X86SpeculativeExecutionSideEffectSuppression();
178}
179
180INITIALIZE_PASS(X86SpeculativeExecutionSideEffectSuppression, "x86-seses",
181 "X86 Speculative Execution Side Effect Suppression", false,
182 false)
assert(UImm &&(UImm !=~static_cast< T >(0)) &&"Invalid immediate!")
const HexagonInstrInfo * TII
#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)
This file defines the 'Statistic' class, which is designed to be an easy way to expose various metric...
#define STATISTIC(VARNAME, DESC)
static cl::opt< bool > OmitBranchLFENCEs("x86-seses-omit-branch-lfences", cl::desc("Omit all lfences before branch instructions."), cl::init(false), cl::Hidden)
static cl::opt< bool > OnlyLFENCENonConst("x86-seses-only-lfence-non-const", cl::desc("Only lfence before groups of terminators where at least one " "branch instruction has an input to the addressing mode that is a " "register other than %rip."), cl::init(false), cl::Hidden)
static cl::opt< bool > OneLFENCEPerBasicBlock("x86-seses-one-lfence-per-bb", cl::desc("Omit all lfences other than the first to be placed in a basic block."), cl::init(false), cl::Hidden)
static cl::opt< bool > EnableSpeculativeExecutionSideEffectSuppression("x86-seses-enable-without-lvi-cfi", cl::desc("Force enable speculative execution side effect suppression. " "(Note: User must pass -mlvi-cfi in order to mitigate indirect " "branches and returns.)"), cl::init(false), cl::Hidden)
static bool hasConstantAddressingMode(const MachineInstr &MI)
Definition X86SpeculativeExecutionSideEffectSuppression.cpp:81
FunctionPass class - This class is used to implement most global optimizations.
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
const TargetSubtargetInfo & getSubtarget() const
getSubtarget - Return the subtarget for which this machine code is being compiled.
StringRef getName() const
getName - Return the name of the corresponding LLVM function.
const TargetMachine & getTarget() const
getTarget - Return the target machine this machine code is compiled with
Representation of each machine instruction.
MachineOperand class - Representation of each machine instruction operand.
CodeGenOptLevel getOptLevel() const
Returns the optimization level: None, Less, Default, or Aggressive.
const X86InstrInfo * getInstrInfo() const override
unsigned ID
LLVM IR allows to use arbitrary numbers as calling convention identifiers.
initializer< Ty > init(const Ty &Val)
This is an optimization pass for GlobalISel generic memory operations.
MachineInstrBuilder BuildMI(MachineFunction &MF, const MIMetadata &MIMD, const MCInstrDesc &MCID)
Builder interface. Specify how to create the initial instruction itself.
FunctionPass * createX86SpeculativeExecutionSideEffectSuppression()
Definition X86SpeculativeExecutionSideEffectSuppression.cpp:176
LLVM_ABI raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.