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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.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "stackmaps"
#include "llvm/CodeGen/StackMaps.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetOpcodes.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include <iterator>
using namespace llvm;
void StackMaps::recordStackMap(const MachineInstr &MI, uint32_t ID,
MachineInstr::const_mop_iterator MOI,
MachineInstr::const_mop_iterator MOE) {
MCContext &OutContext = AP.OutStreamer.getContext();
MCSymbol *MILabel = OutContext.CreateTempSymbol();
AP.OutStreamer.EmitLabel(MILabel);
LocationVec CallsiteLocs;
while (MOI != MOE) {
std::pair<Location, MachineInstr::const_mop_iterator> ParseResult =
OpParser(MOI, MOE);
Location &Loc = ParseResult.first;
// Move large constants into the constant pool.
if (Loc.LocType == Location::Constant && (Loc.Offset & ~0xFFFFFFFFULL)) {
Loc.LocType = Location::ConstantIndex;
Loc.Offset = ConstPool.getConstantIndex(Loc.Offset);
}
CallsiteLocs.push_back(Loc);
MOI = ParseResult.second;
}
const MCExpr *CSOffsetExpr = MCBinaryExpr::CreateSub(
MCSymbolRefExpr::Create(MILabel, OutContext),
MCSymbolRefExpr::Create(AP.CurrentFnSym, OutContext),
OutContext);
CSInfos.push_back(CallsiteInfo(CSOffsetExpr, ID, CallsiteLocs));
}
/// serializeToStackMapSection conceptually populates the following fields:
///
/// uint32 : Reserved (header)
/// uint32 : NumConstants
/// int64 : Constants[NumConstants]
/// uint32 : NumRecords
/// StkMapRecord[NumRecords] {
/// uint32 : PatchPoint ID
/// uint32 : Instruction Offset
/// uint16 : Reserved (record flags)
/// uint16 : NumLocations
/// Location[NumLocations] {
/// uint8 : Register | Direct | Indirect | Constant | ConstantIndex
/// uint8 : Reserved (location flags)
/// uint16 : Dwarf RegNum
/// int32 : Offset
/// }
/// }
///
/// 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::serializeToStackMapSection() {
// Bail out if there's no stack map data.
if (CSInfos.empty())
return;
MCContext &OutContext = AP.OutStreamer.getContext();
const TargetRegisterInfo *TRI = AP.TM.getRegisterInfo();
// Create the section.
const MCSection *StackMapSection =
OutContext.getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps", 0,
SectionKind::getMetadata());
AP.OutStreamer.SwitchSection(StackMapSection);
// Emit a dummy symbol to force section inclusion.
AP.OutStreamer.EmitLabel(
OutContext.GetOrCreateSymbol(Twine("__LLVM_StackMaps")));
// Serialize data.
const char *WSMP = "Stack Maps: ";
const MCRegisterInfo &MCRI = *OutContext.getRegisterInfo();
DEBUG(dbgs() << "********** Stack Map Output **********\n");
// Header.
AP.OutStreamer.EmitIntValue(0, 4);
// Num constants.
AP.OutStreamer.EmitIntValue(ConstPool.getNumConstants(), 4);
// Constant pool entries.
for (unsigned i = 0; i < ConstPool.getNumConstants(); ++i)
AP.OutStreamer.EmitIntValue(ConstPool.getConstant(i), 8);
DEBUG(dbgs() << WSMP << "#callsites = " << CSInfos.size() << "\n");
AP.OutStreamer.EmitIntValue(CSInfos.size(), 4);
for (CallsiteInfoList::const_iterator CSII = CSInfos.begin(),
CSIE = CSInfos.end();
CSII != CSIE; ++CSII) {
unsigned CallsiteID = CSII->ID;
const LocationVec &CSLocs = CSII->Locations;
DEBUG(dbgs() << WSMP << "callsite " << CallsiteID << "\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) {
AP.OutStreamer.EmitIntValue(UINT32_MAX, 4); // Invalid ID.
AP.OutStreamer.EmitValue(CSII->CSOffsetExpr, 4);
AP.OutStreamer.EmitIntValue(0, 2); // Reserved.
AP.OutStreamer.EmitIntValue(0, 2); // 0 locations.
continue;
}
AP.OutStreamer.EmitIntValue(CallsiteID, 4);
AP.OutStreamer.EmitValue(CSII->CSOffsetExpr, 4);
// Reserved for flags.
AP.OutStreamer.EmitIntValue(0, 2);
DEBUG(dbgs() << WSMP << " has " << CSLocs.size() << " locations\n");
AP.OutStreamer.EmitIntValue(CSLocs.size(), 2);
unsigned operIdx = 0;
for (LocationVec::const_iterator LocI = CSLocs.begin(), LocE = CSLocs.end();
LocI != LocE; ++LocI, ++operIdx) {
const Location &Loc = *LocI;
DEBUG(
dbgs() << WSMP << " Loc " << operIdx << ": ";
switch (Loc.LocType) {
case Location::Unprocessed:
dbgs() << "<Unprocessed operand>";
break;
case Location::Register:
dbgs() << "Register " << MCRI.getName(Loc.Reg);
break;
case Location::Direct:
dbgs() << "Direct " << MCRI.getName(Loc.Reg);
if (Loc.Offset)
dbgs() << " + " << Loc.Offset;
break;
case Location::Indirect:
dbgs() << "Indirect " << MCRI.getName(Loc.Reg)
<< " + " << Loc.Offset;
break;
case Location::Constant:
dbgs() << "Constant " << Loc.Offset;
break;
case Location::ConstantIndex:
dbgs() << "Constant Index " << Loc.Offset;
break;
}
dbgs() << "\n";
);
unsigned RegNo = 0;
if(Loc.Reg) {
RegNo = MCRI.getDwarfRegNum(Loc.Reg, false);
for (MCSuperRegIterator SR(Loc.Reg, TRI);
SR.isValid() && (int)RegNo < 0; ++SR) {
RegNo = TRI->getDwarfRegNum(*SR, false);
}
}
else {
assert((Loc.LocType != Location::Register
&& Loc.LocType != Location::Register) &&
"Missing location register");
}
AP.OutStreamer.EmitIntValue(Loc.LocType, 1);
AP.OutStreamer.EmitIntValue(0, 1); // Reserved location flags.
AP.OutStreamer.EmitIntValue(RegNo, 2);
AP.OutStreamer.EmitIntValue(Loc.Offset, 4);
}
}
AP.OutStreamer.AddBlankLine();
CSInfos.clear();
}
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