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llvm-mirror/lib/CodeGen/StackMaps.cpp
Eric Christopher 67c04e77e5 Have MachineFunction cache a pointer to the subtarget to make lookups 
shorter/easier and have the DAG use that to do the same lookup. This
can be used in the future for TargetMachine based caching lookups from
the MachineFunction easily.

Update the MIPS subtarget switching machinery to update this pointer
at the same time it runs.

llvm-svn: 214838
2014-08-05 02:39:49 +00:00

516 lines
18 KiB
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//===---------------------------- StackMaps.cpp ---------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/StackMaps.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOpcodes.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include <iterator>
using namespace llvm;
#define DEBUG_TYPE "stackmaps"
static cl::opt<int> StackMapVersion("stackmap-version", cl::init(1),
cl::desc("Specify the stackmap encoding version (default = 1)"));
const char *StackMaps::WSMP = "Stack Maps: ";
PatchPointOpers::PatchPointOpers(const MachineInstr *MI)
: MI(MI),
HasDef(MI->getOperand(0).isReg() && MI->getOperand(0).isDef() &&
!MI->getOperand(0).isImplicit()),
IsAnyReg(MI->getOperand(getMetaIdx(CCPos)).getImm() == CallingConv::AnyReg)
{
#ifndef NDEBUG
unsigned CheckStartIdx = 0, e = MI->getNumOperands();
while (CheckStartIdx < e && MI->getOperand(CheckStartIdx).isReg() &&
MI->getOperand(CheckStartIdx).isDef() &&
!MI->getOperand(CheckStartIdx).isImplicit())
++CheckStartIdx;
assert(getMetaIdx() == CheckStartIdx &&
"Unexpected additional definition in Patchpoint intrinsic.");
#endif
}
unsigned PatchPointOpers::getNextScratchIdx(unsigned StartIdx) const {
if (!StartIdx)
StartIdx = getVarIdx();
// Find the next scratch register (implicit def and early clobber)
unsigned ScratchIdx = StartIdx, e = MI->getNumOperands();
while (ScratchIdx < e &&
!(MI->getOperand(ScratchIdx).isReg() &&
MI->getOperand(ScratchIdx).isDef() &&
MI->getOperand(ScratchIdx).isImplicit() &&
MI->getOperand(ScratchIdx).isEarlyClobber()))
++ScratchIdx;
assert(ScratchIdx != e && "No scratch register available");
return ScratchIdx;
}
StackMaps::StackMaps(AsmPrinter &AP) : AP(AP) {
if (StackMapVersion != 1)
llvm_unreachable("Unsupported stackmap version!");
}
MachineInstr::const_mop_iterator
StackMaps::parseOperand(MachineInstr::const_mop_iterator MOI,
MachineInstr::const_mop_iterator MOE,
LocationVec &Locs, LiveOutVec &LiveOuts) const {
if (MOI->isImm()) {
switch (MOI->getImm()) {
default: llvm_unreachable("Unrecognized operand type.");
case StackMaps::DirectMemRefOp: {
unsigned Size =
AP.TM.getSubtargetImpl()->getDataLayout()->getPointerSizeInBits();
assert((Size % 8) == 0 && "Need pointer size in bytes.");
Size /= 8;
unsigned Reg = (++MOI)->getReg();
int64_t Imm = (++MOI)->getImm();
Locs.push_back(Location(StackMaps::Location::Direct, Size, Reg, Imm));
break;
}
case StackMaps::IndirectMemRefOp: {
int64_t Size = (++MOI)->getImm();
assert(Size > 0 && "Need a valid size for indirect memory locations.");
unsigned Reg = (++MOI)->getReg();
int64_t Imm = (++MOI)->getImm();
Locs.push_back(Location(StackMaps::Location::Indirect, Size, Reg, Imm));
break;
}
case StackMaps::ConstantOp: {
++MOI;
assert(MOI->isImm() && "Expected constant operand.");
int64_t Imm = MOI->getImm();
Locs.push_back(Location(Location::Constant, sizeof(int64_t), 0, Imm));
break;
}
}
return ++MOI;
}
// The physical register number will ultimately be encoded as a DWARF regno.
// The stack map also records the size of a spill slot that can hold the
// register content. (The runtime can track the actual size of the data type
// if it needs to.)
if (MOI->isReg()) {
// Skip implicit registers (this includes our scratch registers)
if (MOI->isImplicit())
return ++MOI;
assert(TargetRegisterInfo::isPhysicalRegister(MOI->getReg()) &&
"Virtreg operands should have been rewritten before now.");
const TargetRegisterClass *RC =
AP.TM.getSubtargetImpl()->getRegisterInfo()->getMinimalPhysRegClass(
MOI->getReg());
assert(!MOI->getSubReg() && "Physical subreg still around.");
Locs.push_back(
Location(Location::Register, RC->getSize(), MOI->getReg(), 0));
return ++MOI;
}
if (MOI->isRegLiveOut())
LiveOuts = parseRegisterLiveOutMask(MOI->getRegLiveOut());
return ++MOI;
}
/// Go up the super-register chain until we hit a valid dwarf register number.
static unsigned getDwarfRegNum(unsigned Reg, const TargetRegisterInfo *TRI) {
int RegNo = TRI->getDwarfRegNum(Reg, false);
for (MCSuperRegIterator SR(Reg, TRI); SR.isValid() && RegNo < 0; ++SR)
RegNo = TRI->getDwarfRegNum(*SR, false);
assert(RegNo >= 0 && "Invalid Dwarf register number.");
return (unsigned) RegNo;
}
/// Create a live-out register record for the given register Reg.
StackMaps::LiveOutReg
StackMaps::createLiveOutReg(unsigned Reg, const TargetRegisterInfo *TRI) const {
unsigned RegNo = getDwarfRegNum(Reg, TRI);
unsigned Size = TRI->getMinimalPhysRegClass(Reg)->getSize();
return LiveOutReg(Reg, RegNo, Size);
}
/// Parse the register live-out mask and return a vector of live-out registers
/// that need to be recorded in the stackmap.
StackMaps::LiveOutVec
StackMaps::parseRegisterLiveOutMask(const uint32_t *Mask) const {
assert(Mask && "No register mask specified");
const TargetRegisterInfo *TRI = AP.TM.getSubtargetImpl()->getRegisterInfo();
LiveOutVec LiveOuts;
// Create a LiveOutReg for each bit that is set in the register mask.
for (unsigned Reg = 0, NumRegs = TRI->getNumRegs(); Reg != NumRegs; ++Reg)
if ((Mask[Reg / 32] >> Reg % 32) & 1)
LiveOuts.push_back(createLiveOutReg(Reg, TRI));
// We don't need to keep track of a register if its super-register is already
// in the list. Merge entries that refer to the same dwarf register and use
// the maximum size that needs to be spilled.
std::sort(LiveOuts.begin(), LiveOuts.end());
for (LiveOutVec::iterator I = LiveOuts.begin(), E = LiveOuts.end();
I != E; ++I) {
for (LiveOutVec::iterator II = std::next(I); II != E; ++II) {
if (I->RegNo != II->RegNo) {
// Skip all the now invalid entries.
I = --II;
break;
}
I->Size = std::max(I->Size, II->Size);
if (TRI->isSuperRegister(I->Reg, II->Reg))
I->Reg = II->Reg;
II->MarkInvalid();
}
}
LiveOuts.erase(std::remove_if(LiveOuts.begin(), LiveOuts.end(),
LiveOutReg::IsInvalid), LiveOuts.end());
return LiveOuts;
}
void StackMaps::recordStackMapOpers(const MachineInstr &MI, uint64_t ID,
MachineInstr::const_mop_iterator MOI,
MachineInstr::const_mop_iterator MOE,
bool recordResult) {
MCContext &OutContext = AP.OutStreamer.getContext();
MCSymbol *MILabel = OutContext.CreateTempSymbol();
AP.OutStreamer.EmitLabel(MILabel);
LocationVec Locations;
LiveOutVec LiveOuts;
if (recordResult) {
assert(PatchPointOpers(&MI).hasDef() && "Stackmap has no return value.");
parseOperand(MI.operands_begin(), std::next(MI.operands_begin()),
Locations, LiveOuts);
}
// Parse operands.
while (MOI != MOE) {
MOI = parseOperand(MOI, MOE, Locations, LiveOuts);
}
// Move large constants into the constant pool.
for (LocationVec::iterator I = Locations.begin(), E = Locations.end();
I != E; ++I) {
// Constants are encoded as sign-extended integers.
// -1 is directly encoded as .long 0xFFFFFFFF with no constant pool.
if (I->LocType == Location::Constant &&
((I->Offset + (int64_t(1)<<31)) >> 32) != 0) {
I->LocType = Location::ConstantIndex;
auto Result = ConstPool.insert(std::make_pair(I->Offset, I->Offset));
I->Offset = Result.first - ConstPool.begin();
}
}
// Create an expression to calculate the offset of the callsite from function
// entry.
const MCExpr *CSOffsetExpr = MCBinaryExpr::CreateSub(
MCSymbolRefExpr::Create(MILabel, OutContext),
MCSymbolRefExpr::Create(AP.CurrentFnSym, OutContext),
OutContext);
CSInfos.push_back(CallsiteInfo(CSOffsetExpr, ID, Locations, LiveOuts));
// Record the stack size of the current function.
const MachineFrameInfo *MFI = AP.MF->getFrameInfo();
const TargetRegisterInfo *RegInfo = AP.MF->getSubtarget().getRegisterInfo();
const bool DynamicFrameSize = MFI->hasVarSizedObjects() ||
RegInfo->needsStackRealignment(*(AP.MF));
FnStackSize[AP.CurrentFnSym] =
DynamicFrameSize ? UINT64_MAX : MFI->getStackSize();
}
void StackMaps::recordStackMap(const MachineInstr &MI) {
assert(MI.getOpcode() == TargetOpcode::STACKMAP && "expected stackmap");
int64_t ID = MI.getOperand(0).getImm();
recordStackMapOpers(MI, ID, std::next(MI.operands_begin(), 2),
MI.operands_end());
}
void StackMaps::recordPatchPoint(const MachineInstr &MI) {
assert(MI.getOpcode() == TargetOpcode::PATCHPOINT && "expected patchpoint");
PatchPointOpers opers(&MI);
int64_t ID = opers.getMetaOper(PatchPointOpers::IDPos).getImm();
MachineInstr::const_mop_iterator MOI =
std::next(MI.operands_begin(), opers.getStackMapStartIdx());
recordStackMapOpers(MI, ID, MOI, MI.operands_end(),
opers.isAnyReg() && opers.hasDef());
#ifndef NDEBUG
// verify anyregcc
LocationVec &Locations = CSInfos.back().Locations;
if (opers.isAnyReg()) {
unsigned NArgs = opers.getMetaOper(PatchPointOpers::NArgPos).getImm();
for (unsigned i = 0, e = (opers.hasDef() ? NArgs+1 : NArgs); i != e; ++i)
assert(Locations[i].LocType == Location::Register &&
"anyreg arg must be in reg.");
}
#endif
}
/// Emit the stackmap header.
///
/// Header {
/// uint8 : Stack Map Version (currently 1)
/// uint8 : Reserved (expected to be 0)
/// uint16 : Reserved (expected to be 0)
/// }
/// uint32 : NumFunctions
/// uint32 : NumConstants
/// uint32 : NumRecords
void StackMaps::emitStackmapHeader(MCStreamer &OS) {
// Header.
OS.EmitIntValue(StackMapVersion, 1); // Version.
OS.EmitIntValue(0, 1); // Reserved.
OS.EmitIntValue(0, 2); // Reserved.
// Num functions.
DEBUG(dbgs() << WSMP << "#functions = " << FnStackSize.size() << '\n');
OS.EmitIntValue(FnStackSize.size(), 4);
// Num constants.
DEBUG(dbgs() << WSMP << "#constants = " << ConstPool.size() << '\n');
OS.EmitIntValue(ConstPool.size(), 4);
// Num callsites.
DEBUG(dbgs() << WSMP << "#callsites = " << CSInfos.size() << '\n');
OS.EmitIntValue(CSInfos.size(), 4);
}
/// Emit the function frame record for each function.
///
/// StkSizeRecord[NumFunctions] {
/// uint64 : Function Address
/// uint64 : Stack Size
/// }
void StackMaps::emitFunctionFrameRecords(MCStreamer &OS) {
// Function Frame records.
DEBUG(dbgs() << WSMP << "functions:\n");
for (auto const &FR : FnStackSize) {
DEBUG(dbgs() << WSMP << "function addr: " << FR.first
<< " frame size: " << FR.second);
OS.EmitSymbolValue(FR.first, 8);
OS.EmitIntValue(FR.second, 8);
}
}
/// Emit the constant pool.
///
/// int64 : Constants[NumConstants]
void StackMaps::emitConstantPoolEntries(MCStreamer &OS) {
// Constant pool entries.
DEBUG(dbgs() << WSMP << "constants:\n");
for (auto ConstEntry : ConstPool) {
DEBUG(dbgs() << WSMP << ConstEntry.second << '\n');
OS.EmitIntValue(ConstEntry.second, 8);
}
}
/// Emit the callsite info for each callsite.
///
/// StkMapRecord[NumRecords] {
/// uint64 : PatchPoint ID
/// uint32 : Instruction Offset
/// uint16 : Reserved (record flags)
/// uint16 : NumLocations
/// Location[NumLocations] {
/// uint8 : Register | Direct | Indirect | Constant | ConstantIndex
/// uint8 : Size in Bytes
/// uint16 : Dwarf RegNum
/// int32 : Offset
/// }
/// uint16 : Padding
/// uint16 : NumLiveOuts
/// LiveOuts[NumLiveOuts] {
/// uint16 : Dwarf RegNum
/// uint8 : Reserved
/// uint8 : Size in Bytes
/// }
/// uint32 : Padding (only if required to align to 8 byte)
/// }
///
/// Location Encoding, Type, Value:
/// 0x1, Register, Reg (value in register)
/// 0x2, Direct, Reg + Offset (frame index)
/// 0x3, Indirect, [Reg + Offset] (spilled value)
/// 0x4, Constant, Offset (small constant)
/// 0x5, ConstIndex, Constants[Offset] (large constant)
void StackMaps::emitCallsiteEntries(MCStreamer &OS,
const TargetRegisterInfo *TRI) {
// Callsite entries.
DEBUG(dbgs() << WSMP << "callsites:\n");
for (const auto &CSI : CSInfos) {
const LocationVec &CSLocs = CSI.Locations;
const LiveOutVec &LiveOuts = CSI.LiveOuts;
DEBUG(dbgs() << WSMP << "callsite " << CSI.ID << "\n");
// Verify stack map entry. It's better to communicate a problem to the
// runtime than crash in case of in-process compilation. Currently, we do
// simple overflow checks, but we may eventually communicate other
// compilation errors this way.
if (CSLocs.size() > UINT16_MAX || LiveOuts.size() > UINT16_MAX) {
OS.EmitIntValue(UINT64_MAX, 8); // Invalid ID.
OS.EmitValue(CSI.CSOffsetExpr, 4);
OS.EmitIntValue(0, 2); // Reserved.
OS.EmitIntValue(0, 2); // 0 locations.
OS.EmitIntValue(0, 2); // padding.
OS.EmitIntValue(0, 2); // 0 live-out registers.
OS.EmitIntValue(0, 4); // padding.
continue;
}
OS.EmitIntValue(CSI.ID, 8);
OS.EmitValue(CSI.CSOffsetExpr, 4);
// Reserved for flags.
OS.EmitIntValue(0, 2);
DEBUG(dbgs() << WSMP << " has " << CSLocs.size() << " locations\n");
OS.EmitIntValue(CSLocs.size(), 2);
unsigned OperIdx = 0;
for (const auto &Loc : CSLocs) {
unsigned RegNo = 0;
int Offset = Loc.Offset;
if(Loc.Reg) {
RegNo = getDwarfRegNum(Loc.Reg, TRI);
// If this is a register location, put the subregister byte offset in
// the location offset.
if (Loc.LocType == Location::Register) {
assert(!Loc.Offset && "Register location should have zero offset");
unsigned LLVMRegNo = TRI->getLLVMRegNum(RegNo, false);
unsigned SubRegIdx = TRI->getSubRegIndex(LLVMRegNo, Loc.Reg);
if (SubRegIdx)
Offset = TRI->getSubRegIdxOffset(SubRegIdx);
}
}
else {
assert(Loc.LocType != Location::Register &&
"Missing location register");
}
DEBUG(dbgs() << WSMP << " Loc " << OperIdx << ": ";
switch (Loc.LocType) {
case Location::Unprocessed:
dbgs() << "<Unprocessed operand>";
break;
case Location::Register:
dbgs() << "Register " << TRI->getName(Loc.Reg);
break;
case Location::Direct:
dbgs() << "Direct " << TRI->getName(Loc.Reg);
if (Loc.Offset)
dbgs() << " + " << Loc.Offset;
break;
case Location::Indirect:
dbgs() << "Indirect " << TRI->getName(Loc.Reg)
<< " + " << Loc.Offset;
break;
case Location::Constant:
dbgs() << "Constant " << Loc.Offset;
break;
case Location::ConstantIndex:
dbgs() << "Constant Index " << Loc.Offset;
break;
}
dbgs() << " [encoding: .byte " << Loc.LocType
<< ", .byte " << Loc.Size
<< ", .short " << RegNo
<< ", .int " << Offset << "]\n";
);
OS.EmitIntValue(Loc.LocType, 1);
OS.EmitIntValue(Loc.Size, 1);
OS.EmitIntValue(RegNo, 2);
OS.EmitIntValue(Offset, 4);
OperIdx++;
}
DEBUG(dbgs() << WSMP << " has " << LiveOuts.size()
<< " live-out registers\n");
// Num live-out registers and padding to align to 4 byte.
OS.EmitIntValue(0, 2);
OS.EmitIntValue(LiveOuts.size(), 2);
OperIdx = 0;
for (const auto &LO : LiveOuts) {
DEBUG(dbgs() << WSMP << " LO " << OperIdx << ": "
<< TRI->getName(LO.Reg)
<< " [encoding: .short " << LO.RegNo
<< ", .byte 0, .byte " << LO.Size << "]\n");
OS.EmitIntValue(LO.RegNo, 2);
OS.EmitIntValue(0, 1);
OS.EmitIntValue(LO.Size, 1);
}
// Emit alignment to 8 byte.
OS.EmitValueToAlignment(8);
}
}
/// Serialize the stackmap data.
void StackMaps::serializeToStackMapSection() {
(void) WSMP;
// Bail out if there's no stack map data.
assert((!CSInfos.empty() || (CSInfos.empty() && ConstPool.empty())) &&
"Expected empty constant pool too!");
assert((!CSInfos.empty() || (CSInfos.empty() && FnStackSize.empty())) &&
"Expected empty function record too!");
if (CSInfos.empty())
return;
MCContext &OutContext = AP.OutStreamer.getContext();
MCStreamer &OS = AP.OutStreamer;
const TargetRegisterInfo *TRI = AP.TM.getSubtargetImpl()->getRegisterInfo();
// Create the section.
const MCSection *StackMapSection =
OutContext.getObjectFileInfo()->getStackMapSection();
OS.SwitchSection(StackMapSection);
// Emit a dummy symbol to force section inclusion.
OS.EmitLabel(OutContext.GetOrCreateSymbol(Twine("__LLVM_StackMaps")));
// Serialize data.
DEBUG(dbgs() << "********** Stack Map Output **********\n");
emitStackmapHeader(OS);
emitFunctionFrameRecords(OS);
emitConstantPoolEntries(OS);
emitCallsiteEntries(OS, TRI);
OS.AddBlankLine();
// Clean up.
CSInfos.clear();
ConstPool.clear();
}
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