1,399 changes: 1,399 additions & 0 deletions llvm/lib/CodeGen/MachineOutliner.cpp
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6 changes: 6 additions & 0 deletions llvm/lib/CodeGen/TargetPassConfig.cpp
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Expand Up @@ -92,6 +92,9 @@ static cl::opt<bool> VerifyMachineCode("verify-machineinstrs", cl::Hidden,
cl::desc("Verify generated machine code"),
cl::init(false),
cl::ZeroOrMore);
static cl::opt<bool> EnableMachineOutliner("enable-machine-outliner",
cl::Hidden,
cl::desc("Enable machine outliner"));

static cl::opt<std::string>
PrintMachineInstrs("print-machineinstrs", cl::ValueOptional,
Expand Down Expand Up @@ -674,6 +677,9 @@ void TargetPassConfig::addMachinePasses() {
addPass(&XRayInstrumentationID, false);
addPass(&PatchableFunctionID, false);

if (EnableMachineOutliner)
PM->add(createMachineOutlinerPass());

AddingMachinePasses = false;
}

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80 changes: 80 additions & 0 deletions llvm/lib/Target/X86/X86InstrInfo.cpp
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Expand Up @@ -10383,3 +10383,83 @@ namespace {
char LDTLSCleanup::ID = 0;
FunctionPass*
llvm::createCleanupLocalDynamicTLSPass() { return new LDTLSCleanup(); }

unsigned X86InstrInfo::getOutliningBenefit(size_t SequenceSize,
size_t Occurrences) const {
unsigned NotOutlinedSize = SequenceSize * Occurrences;

// Sequence appears once in outlined function (Sequence.size())
// One return instruction (+1)
// One call per occurrence (Occurrences)
unsigned OutlinedSize = (SequenceSize + 1) + Occurrences;

// Return the number of instructions saved by outlining this sequence.
return NotOutlinedSize > OutlinedSize ? NotOutlinedSize - OutlinedSize : 0;
}

bool X86InstrInfo::isFunctionSafeToOutlineFrom(MachineFunction &MF) const {
return MF.getFunction()->hasFnAttribute(Attribute::NoRedZone);
}

X86GenInstrInfo::MachineOutlinerInstrType
X86InstrInfo::getOutliningType(MachineInstr &MI) const {

// Don't outline returns or basic block terminators.
if (MI.isReturn() || MI.isTerminator())
return MachineOutlinerInstrType::Illegal;

// Don't outline anything that modifies or reads from the stack pointer.
//
// FIXME: There are instructions which are being manually built without
// explicit uses/defs so we also have to check the MCInstrDesc. We should be
// able to remove the extra checks once those are fixed up. For example,
// sometimes we might get something like %RAX<def> = POP64r 1. This won't be
// caught by modifiesRegister or readsRegister even though the instruction
// really ought to be formed so that modifiesRegister/readsRegister would
// catch it.
if (MI.modifiesRegister(X86::RSP, &RI) || MI.readsRegister(X86::RSP, &RI) ||
MI.getDesc().hasImplicitUseOfPhysReg(X86::RSP) ||
MI.getDesc().hasImplicitDefOfPhysReg(X86::RSP))
return MachineOutlinerInstrType::Illegal;

if (MI.readsRegister(X86::RIP, &RI) ||
MI.getDesc().hasImplicitUseOfPhysReg(X86::RIP) ||
MI.getDesc().hasImplicitDefOfPhysReg(X86::RIP))
return MachineOutlinerInstrType::Illegal;

if (MI.isPosition())
return MachineOutlinerInstrType::Illegal;

for (const MachineOperand &MOP : MI.operands())
if (MOP.isCPI() || MOP.isJTI() || MOP.isCFIIndex() || MOP.isFI() ||
MOP.isTargetIndex())
return MachineOutlinerInstrType::Illegal;

// Don't allow debug values to impact outlining type.
if (MI.isDebugValue() || MI.isIndirectDebugValue())
return MachineOutlinerInstrType::Invisible;

return MachineOutlinerInstrType::Legal;
}

void X86InstrInfo::insertOutlinerEpilogue(MachineBasicBlock &MBB,
MachineFunction &MF) const {

MachineInstr *retq = BuildMI(MF, DebugLoc(), get(X86::RETQ));
MBB.insert(MBB.end(), retq);
}

void X86InstrInfo::insertOutlinerPrologue(MachineBasicBlock &MBB,
MachineFunction &MF) const {
return;
}

MachineBasicBlock::iterator
X86InstrInfo::insertOutlinedCall(Module &M, MachineBasicBlock &MBB,
MachineBasicBlock::iterator &It,
MachineFunction &MF) const {
It = MBB.insert(It,
BuildMI(MF, DebugLoc(), get(X86::CALL64pcrel32))
.addGlobalAddress(M.getNamedValue(MF.getName())));
return It;
}
19 changes: 19 additions & 0 deletions llvm/lib/Target/X86/X86InstrInfo.h
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Expand Up @@ -545,6 +545,25 @@ class X86InstrInfo final : public X86GenInstrInfo {

bool isTailCall(const MachineInstr &Inst) const override;

unsigned getOutliningBenefit(size_t SequenceSize,
size_t Occurrences) const override;

bool isFunctionSafeToOutlineFrom(MachineFunction &MF) const override;

llvm::X86GenInstrInfo::MachineOutlinerInstrType
getOutliningType(MachineInstr &MI) const override;

void insertOutlinerEpilogue(MachineBasicBlock &MBB,
MachineFunction &MF) const override;

void insertOutlinerPrologue(MachineBasicBlock &MBB,
MachineFunction &MF) const override;

MachineBasicBlock::iterator
insertOutlinedCall(Module &M, MachineBasicBlock &MBB,
MachineBasicBlock::iterator &It,
MachineFunction &MF) const override;

protected:
/// Commutes the operands in the given instruction by changing the operands
/// order and/or changing the instruction's opcode and/or the immediate value
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75 changes: 75 additions & 0 deletions llvm/test/CodeGen/X86/machine-outliner-debuginfo.ll
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@@ -0,0 +1,75 @@
; RUN: llc -enable-machine-outliner -mtriple=x86_64-apple-darwin < %s | FileCheck %s

@x = global i32 0, align 4, !dbg !0

define i32 @main() #0 !dbg !11 {
; CHECK-LABEL: _main:
%1 = alloca i32, align 4
%2 = alloca i32, align 4
%3 = alloca i32, align 4
%4 = alloca i32, align 4
%5 = alloca i32, align 4
; There is a debug value in the middle of this section, make sure debug values are ignored.
; CHECK: callq l_OUTLINED_FUNCTION_0
store i32 1, i32* %2, align 4
store i32 2, i32* %3, align 4
store i32 3, i32* %4, align 4
call void @llvm.dbg.value(metadata i32 10, i64 0, metadata !15, metadata !16), !dbg !17
store i32 4, i32* %5, align 4
store i32 0, i32* @x, align 4, !dbg !24
; This is the same sequence of instructions without a debug value. It should be outlined
; in the same way.
; CHECK: callq l_OUTLINED_FUNCTION_0
store i32 1, i32* %2, align 4
store i32 2, i32* %3, align 4
store i32 3, i32* %4, align 4
store i32 4, i32* %5, align 4
store i32 1, i32* @x, align 4, !dbg !14
ret i32 0, !dbg !25
}

; CHECK-LABEL: l_OUTLINED_FUNCTION_0:
; CHECK-NOT: .loc {{[0-9]+}} {{[0-9]+}} {{[0-9]+}} {{^(is_stmt)}}
; CHECK-NOT: ##DEBUG_VALUE: main:{{[a-z]}} <- {{[0-9]+}}
; CHECK: movl $1, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: movl $2, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: movl $3, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: movl $4, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: retq

declare void @llvm.dbg.declare(metadata, metadata, metadata) #1

declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1

attributes #0 = { noredzone nounwind ssp uwtable "no-frame-pointer-elim"="true" }

!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!7, !8, !9}
!llvm.ident = !{!10}

!0 = !DIGlobalVariableExpression(var: !1)
!1 = distinct !DIGlobalVariable(name: "x", scope: !2, file: !3, line: 2, type: !6, isLocal: false, isDefinition: true)
!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 5.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
!3 = !DIFile(filename: "debug-test.c", directory: "dir")
!4 = !{}
!5 = !{!0}
!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!7 = !{i32 2, !"Dwarf Version", i32 4}
!8 = !{i32 2, !"Debug Info Version", i32 3}
!9 = !{i32 1, !"PIC Level", i32 2}
!10 = !{!"clang version 5.0.0"}
!11 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 4, type: !12, isLocal: false, isDefinition: true, scopeLine: 4, flags: DIFlagPrototyped, isOptimized: false, unit: !2, variables: !4)
!12 = !DISubroutineType(types: !13)
!13 = !{!6}
!14 = !DILocation(line: 7, column: 4, scope: !11)
!15 = !DILocalVariable(name: "a", scope: !11, file: !3, line: 5, type: !6)
!16 = !DIExpression()
!17 = !DILocation(line: 5, column: 6, scope: !11)
!18 = !DILocalVariable(name: "b", scope: !11, file: !3, line: 5, type: !6)
!19 = !DILocation(line: 5, column: 9, scope: !11)
!20 = !DILocalVariable(name: "c", scope: !11, file: !3, line: 5, type: !6)
!21 = !DILocation(line: 5, column: 12, scope: !11)
!22 = !DILocalVariable(name: "d", scope: !11, file: !3, line: 5, type: !6)
!23 = !DILocation(line: 5, column: 15, scope: !11)
!24 = !DILocation(line: 14, column: 4, scope: !11)
!25 = !DILocation(line: 21, column: 2, scope: !11)
110 changes: 110 additions & 0 deletions llvm/test/CodeGen/X86/machine-outliner.ll
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@@ -0,0 +1,110 @@
; RUN: llc -enable-machine-outliner -mtriple=x86_64-apple-darwin < %s | FileCheck %s

@x = global i32 0, align 4

define i32 @check_boundaries() #0 {
; CHECK-LABEL: _check_boundaries:
%1 = alloca i32, align 4
%2 = alloca i32, align 4
%3 = alloca i32, align 4
%4 = alloca i32, align 4
%5 = alloca i32, align 4
store i32 0, i32* %1, align 4
store i32 0, i32* %2, align 4
%6 = load i32, i32* %2, align 4
%7 = icmp ne i32 %6, 0
br i1 %7, label %9, label %8

; CHECK: callq l_OUTLINED_FUNCTION_1
; CHECK: cmpl $0, -{{[0-9]+}}(%rbp)
store i32 1, i32* %2, align 4
store i32 2, i32* %3, align 4
store i32 3, i32* %4, align 4
store i32 4, i32* %5, align 4
br label %10

store i32 1, i32* %4, align 4
br label %10

%11 = load i32, i32* %2, align 4
%12 = icmp ne i32 %11, 0
br i1 %12, label %14, label %13

; CHECK: callq l_OUTLINED_FUNCTION_1
store i32 1, i32* %2, align 4
store i32 2, i32* %3, align 4
store i32 3, i32* %4, align 4
store i32 4, i32* %5, align 4
br label %15

store i32 1, i32* %4, align 4
br label %15

ret i32 0
}

define i32 @empty_1() #0 {
; CHECK-LABEL: _empty_1:
; CHECK-NOT: callq l_OUTLINED_FUNCTION_{{[0-9]+}}
ret i32 1
}

define i32 @empty_2() #0 {
; CHECK-LABEL: _empty_2
; CHECK-NOT: callq l_OUTLINED_FUNCTION_{{[0-9]+}}
ret i32 1
}

define i32 @no_empty_outlining() #0 {
; CHECK-LABEL: _no_empty_outlining:
%1 = alloca i32, align 4
store i32 0, i32* %1, align 4
; CHECK-NOT: callq l_OUTLINED_FUNCTION_{{[0-9]+}}
%2 = call i32 @empty_1() #1
%3 = call i32 @empty_2() #1
%4 = call i32 @empty_1() #1
%5 = call i32 @empty_2() #1
%6 = call i32 @empty_1() #1
%7 = call i32 @empty_2() #1
ret i32 0
}

define i32 @main() #0 {
; CHECK-LABEL: _main:
%1 = alloca i32, align 4
%2 = alloca i32, align 4
%3 = alloca i32, align 4
%4 = alloca i32, align 4
%5 = alloca i32, align 4

store i32 0, i32* %1, align 4
store i32 0, i32* @x, align 4
; CHECK: callq l_OUTLINED_FUNCTION_0
store i32 1, i32* %2, align 4
store i32 2, i32* %3, align 4
store i32 3, i32* %4, align 4
store i32 4, i32* %5, align 4
store i32 1, i32* @x, align 4
; CHECK: callq l_OUTLINED_FUNCTION_0
store i32 1, i32* %2, align 4
store i32 2, i32* %3, align 4
store i32 3, i32* %4, align 4
store i32 4, i32* %5, align 4
ret i32 0
}

attributes #0 = { noredzone nounwind ssp uwtable "no-frame-pointer-elim"="true" }

; CHECK-LABEL: l_OUTLINED_FUNCTION_0:
; CHECK: movl $1, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: movl $2, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: movl $3, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: movl $4, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: retq

; CHECK-LABEL: l_OUTLINED_FUNCTION_1:
; CHECK: movl $1, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: movl $2, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: movl $3, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: movl $4, -{{[0-9]+}}(%rbp)
; CHECK-NEXT: retq