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| Current File : //usr/src/contrib/llvm/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp |
//===----- JITDwarfEmitter.cpp - Write dwarf tables into memory -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a JITDwarfEmitter object that is used by the JIT to
// write dwarf tables to memory.
//
//===----------------------------------------------------------------------===//
#include "JIT.h"
#include "JITDwarfEmitter.h"
#include "llvm/Function.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/CodeGen/JITCodeEmitter.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/ExecutionEngine/JITMemoryManager.h"
#include "llvm/MC/MachineLocation.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
using namespace llvm;
JITDwarfEmitter::JITDwarfEmitter(JIT& theJit) : MMI(0), Jit(theJit) {}
unsigned char* JITDwarfEmitter::EmitDwarfTable(MachineFunction& F,
JITCodeEmitter& jce,
unsigned char* StartFunction,
unsigned char* EndFunction,
unsigned char* &EHFramePtr) {
assert(MMI && "MachineModuleInfo not registered!");
const TargetMachine& TM = F.getTarget();
TD = TM.getTargetData();
stackGrowthDirection = TM.getFrameLowering()->getStackGrowthDirection();
RI = TM.getRegisterInfo();
MAI = TM.getMCAsmInfo();
JCE = &jce;
unsigned char* ExceptionTable = EmitExceptionTable(&F, StartFunction,
EndFunction);
unsigned char* Result = 0;
const std::vector<const Function *> Personalities = MMI->getPersonalities();
EHFramePtr = EmitCommonEHFrame(Personalities[MMI->getPersonalityIndex()]);
Result = EmitEHFrame(Personalities[MMI->getPersonalityIndex()], EHFramePtr,
StartFunction, EndFunction, ExceptionTable);
return Result;
}
void
JITDwarfEmitter::EmitFrameMoves(intptr_t BaseLabelPtr,
const std::vector<MachineMove> &Moves) const {
unsigned PointerSize = TD->getPointerSize();
int stackGrowth = stackGrowthDirection == TargetFrameLowering::StackGrowsUp ?
PointerSize : -PointerSize;
MCSymbol *BaseLabel = 0;
for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
const MachineMove &Move = Moves[i];
MCSymbol *Label = Move.getLabel();
// Throw out move if the label is invalid.
if (Label && (*JCE->getLabelLocations())[Label] == 0)
continue;
intptr_t LabelPtr = 0;
if (Label) LabelPtr = JCE->getLabelAddress(Label);
const MachineLocation &Dst = Move.getDestination();
const MachineLocation &Src = Move.getSource();
// Advance row if new location.
if (BaseLabelPtr && Label && BaseLabel != Label) {
JCE->emitByte(dwarf::DW_CFA_advance_loc4);
JCE->emitInt32(LabelPtr - BaseLabelPtr);
BaseLabel = Label;
BaseLabelPtr = LabelPtr;
}
// If advancing cfa.
if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
if (!Src.isReg()) {
if (Src.getReg() == MachineLocation::VirtualFP) {
JCE->emitByte(dwarf::DW_CFA_def_cfa_offset);
} else {
JCE->emitByte(dwarf::DW_CFA_def_cfa);
JCE->emitULEB128Bytes(RI->getDwarfRegNum(Src.getReg(), true));
}
JCE->emitULEB128Bytes(-Src.getOffset());
} else {
llvm_unreachable("Machine move not supported yet.");
}
} else if (Src.isReg() &&
Src.getReg() == MachineLocation::VirtualFP) {
if (Dst.isReg()) {
JCE->emitByte(dwarf::DW_CFA_def_cfa_register);
JCE->emitULEB128Bytes(RI->getDwarfRegNum(Dst.getReg(), true));
} else {
llvm_unreachable("Machine move not supported yet.");
}
} else {
unsigned Reg = RI->getDwarfRegNum(Src.getReg(), true);
int Offset = Dst.getOffset() / stackGrowth;
if (Offset < 0) {
JCE->emitByte(dwarf::DW_CFA_offset_extended_sf);
JCE->emitULEB128Bytes(Reg);
JCE->emitSLEB128Bytes(Offset);
} else if (Reg < 64) {
JCE->emitByte(dwarf::DW_CFA_offset + Reg);
JCE->emitULEB128Bytes(Offset);
} else {
JCE->emitByte(dwarf::DW_CFA_offset_extended);
JCE->emitULEB128Bytes(Reg);
JCE->emitULEB128Bytes(Offset);
}
}
}
}
/// SharedTypeIds - How many leading type ids two landing pads have in common.
static unsigned SharedTypeIds(const LandingPadInfo *L,
const LandingPadInfo *R) {
const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
unsigned LSize = LIds.size(), RSize = RIds.size();
unsigned MinSize = LSize < RSize ? LSize : RSize;
unsigned Count = 0;
for (; Count != MinSize; ++Count)
if (LIds[Count] != RIds[Count])
return Count;
return Count;
}
/// PadLT - Order landing pads lexicographically by type id.
static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
unsigned LSize = LIds.size(), RSize = RIds.size();
unsigned MinSize = LSize < RSize ? LSize : RSize;
for (unsigned i = 0; i != MinSize; ++i)
if (LIds[i] != RIds[i])
return LIds[i] < RIds[i];
return LSize < RSize;
}
namespace {
/// ActionEntry - Structure describing an entry in the actions table.
struct ActionEntry {
int ValueForTypeID; // The value to write - may not be equal to the type id.
int NextAction;
struct ActionEntry *Previous;
};
/// PadRange - Structure holding a try-range and the associated landing pad.
struct PadRange {
// The index of the landing pad.
unsigned PadIndex;
// The index of the begin and end labels in the landing pad's label lists.
unsigned RangeIndex;
};
typedef DenseMap<MCSymbol*, PadRange> RangeMapType;
/// CallSiteEntry - Structure describing an entry in the call-site table.
struct CallSiteEntry {
MCSymbol *BeginLabel; // zero indicates the start of the function.
MCSymbol *EndLabel; // zero indicates the end of the function.
MCSymbol *PadLabel; // zero indicates that there is no landing pad.
unsigned Action;
};
}
unsigned char* JITDwarfEmitter::EmitExceptionTable(MachineFunction* MF,
unsigned char* StartFunction,
unsigned char* EndFunction) const {
assert(MMI && "MachineModuleInfo not registered!");
// Map all labels and get rid of any dead landing pads.
MMI->TidyLandingPads(JCE->getLabelLocations());
const std::vector<const GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
if (PadInfos.empty()) return 0;
// Sort the landing pads in order of their type ids. This is used to fold
// duplicate actions.
SmallVector<const LandingPadInfo *, 64> LandingPads;
LandingPads.reserve(PadInfos.size());
for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
LandingPads.push_back(&PadInfos[i]);
std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
// Negative type ids index into FilterIds, positive type ids index into
// TypeInfos. The value written for a positive type id is just the type
// id itself. For a negative type id, however, the value written is the
// (negative) byte offset of the corresponding FilterIds entry. The byte
// offset is usually equal to the type id, because the FilterIds entries
// are written using a variable width encoding which outputs one byte per
// entry as long as the value written is not too large, but can differ.
// This kind of complication does not occur for positive type ids because
// type infos are output using a fixed width encoding.
// FilterOffsets[i] holds the byte offset corresponding to FilterIds[i].
SmallVector<int, 16> FilterOffsets;
FilterOffsets.reserve(FilterIds.size());
int Offset = -1;
for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
E = FilterIds.end(); I != E; ++I) {
FilterOffsets.push_back(Offset);
Offset -= MCAsmInfo::getULEB128Size(*I);
}
// Compute the actions table and gather the first action index for each
// landing pad site.
SmallVector<ActionEntry, 32> Actions;
SmallVector<unsigned, 64> FirstActions;
FirstActions.reserve(LandingPads.size());
int FirstAction = 0;
unsigned SizeActions = 0;
for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
const LandingPadInfo *LP = LandingPads[i];
const std::vector<int> &TypeIds = LP->TypeIds;
const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
unsigned SizeSiteActions = 0;
if (NumShared < TypeIds.size()) {
unsigned SizeAction = 0;
ActionEntry *PrevAction = 0;
if (NumShared) {
const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
assert(Actions.size());
PrevAction = &Actions.back();
SizeAction = MCAsmInfo::getSLEB128Size(PrevAction->NextAction) +
MCAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
for (unsigned j = NumShared; j != SizePrevIds; ++j) {
SizeAction -= MCAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
SizeAction += -PrevAction->NextAction;
PrevAction = PrevAction->Previous;
}
}
// Compute the actions.
for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
int TypeID = TypeIds[I];
assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
unsigned SizeTypeID = MCAsmInfo::getSLEB128Size(ValueForTypeID);
int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
SizeAction = SizeTypeID + MCAsmInfo::getSLEB128Size(NextAction);
SizeSiteActions += SizeAction;
ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
Actions.push_back(Action);
PrevAction = &Actions.back();
}
// Record the first action of the landing pad site.
FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
} // else identical - re-use previous FirstAction
FirstActions.push_back(FirstAction);
// Compute this sites contribution to size.
SizeActions += SizeSiteActions;
}
// Compute the call-site table. Entries must be ordered by address.
SmallVector<CallSiteEntry, 64> CallSites;
RangeMapType PadMap;
for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
const LandingPadInfo *LandingPad = LandingPads[i];
for (unsigned j=0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
MCSymbol *BeginLabel = LandingPad->BeginLabels[j];
assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
PadRange P = { i, j };
PadMap[BeginLabel] = P;
}
}
bool MayThrow = false;
MCSymbol *LastLabel = 0;
for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
I != E; ++I) {
for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
MI != E; ++MI) {
if (!MI->isLabel()) {
MayThrow |= MI->isCall();
continue;
}
MCSymbol *BeginLabel = MI->getOperand(0).getMCSymbol();
assert(BeginLabel && "Invalid label!");
if (BeginLabel == LastLabel)
MayThrow = false;
RangeMapType::iterator L = PadMap.find(BeginLabel);
if (L == PadMap.end())
continue;
PadRange P = L->second;
const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
"Inconsistent landing pad map!");
// If some instruction between the previous try-range and this one may
// throw, create a call-site entry with no landing pad for the region
// between the try-ranges.
if (MayThrow) {
CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
CallSites.push_back(Site);
}
LastLabel = LandingPad->EndLabels[P.RangeIndex];
CallSiteEntry Site = {BeginLabel, LastLabel,
LandingPad->LandingPadLabel, FirstActions[P.PadIndex]};
assert(Site.BeginLabel && Site.EndLabel && Site.PadLabel &&
"Invalid landing pad!");
// Try to merge with the previous call-site.
if (CallSites.size()) {
CallSiteEntry &Prev = CallSites.back();
if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
// Extend the range of the previous entry.
Prev.EndLabel = Site.EndLabel;
continue;
}
}
// Otherwise, create a new call-site.
CallSites.push_back(Site);
}
}
// If some instruction between the previous try-range and the end of the
// function may throw, create a call-site entry with no landing pad for the
// region following the try-range.
if (MayThrow) {
CallSiteEntry Site = {LastLabel, 0, 0, 0};
CallSites.push_back(Site);
}
// Final tallies.
unsigned SizeSites = CallSites.size() * (sizeof(int32_t) + // Site start.
sizeof(int32_t) + // Site length.
sizeof(int32_t)); // Landing pad.
for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
SizeSites += MCAsmInfo::getULEB128Size(CallSites[i].Action);
unsigned SizeTypes = TypeInfos.size() * TD->getPointerSize();
unsigned TypeOffset = sizeof(int8_t) + // Call site format
// Call-site table length
MCAsmInfo::getULEB128Size(SizeSites) +
SizeSites + SizeActions + SizeTypes;
// Begin the exception table.
JCE->emitAlignmentWithFill(4, 0);
// Asm->EOL("Padding");
unsigned char* DwarfExceptionTable = (unsigned char*)JCE->getCurrentPCValue();
// Emit the header.
JCE->emitByte(dwarf::DW_EH_PE_omit);
// Asm->EOL("LPStart format (DW_EH_PE_omit)");
JCE->emitByte(dwarf::DW_EH_PE_absptr);
// Asm->EOL("TType format (DW_EH_PE_absptr)");
JCE->emitULEB128Bytes(TypeOffset);
// Asm->EOL("TType base offset");
JCE->emitByte(dwarf::DW_EH_PE_udata4);
// Asm->EOL("Call site format (DW_EH_PE_udata4)");
JCE->emitULEB128Bytes(SizeSites);
// Asm->EOL("Call-site table length");
// Emit the landing pad site information.
for (unsigned i = 0; i < CallSites.size(); ++i) {
CallSiteEntry &S = CallSites[i];
intptr_t BeginLabelPtr = 0;
intptr_t EndLabelPtr = 0;
if (!S.BeginLabel) {
BeginLabelPtr = (intptr_t)StartFunction;
JCE->emitInt32(0);
} else {
BeginLabelPtr = JCE->getLabelAddress(S.BeginLabel);
JCE->emitInt32(BeginLabelPtr - (intptr_t)StartFunction);
}
// Asm->EOL("Region start");
if (!S.EndLabel)
EndLabelPtr = (intptr_t)EndFunction;
else
EndLabelPtr = JCE->getLabelAddress(S.EndLabel);
JCE->emitInt32(EndLabelPtr - BeginLabelPtr);
//Asm->EOL("Region length");
if (!S.PadLabel) {
JCE->emitInt32(0);
} else {
unsigned PadLabelPtr = JCE->getLabelAddress(S.PadLabel);
JCE->emitInt32(PadLabelPtr - (intptr_t)StartFunction);
}
// Asm->EOL("Landing pad");
JCE->emitULEB128Bytes(S.Action);
// Asm->EOL("Action");
}
// Emit the actions.
for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
ActionEntry &Action = Actions[I];
JCE->emitSLEB128Bytes(Action.ValueForTypeID);
//Asm->EOL("TypeInfo index");
JCE->emitSLEB128Bytes(Action.NextAction);
//Asm->EOL("Next action");
}
// Emit the type ids.
for (unsigned M = TypeInfos.size(); M; --M) {
const GlobalVariable *GV = TypeInfos[M - 1];
if (GV) {
if (TD->getPointerSize() == sizeof(int32_t))
JCE->emitInt32((intptr_t)Jit.getOrEmitGlobalVariable(GV));
else
JCE->emitInt64((intptr_t)Jit.getOrEmitGlobalVariable(GV));
} else {
if (TD->getPointerSize() == sizeof(int32_t))
JCE->emitInt32(0);
else
JCE->emitInt64(0);
}
// Asm->EOL("TypeInfo");
}
// Emit the filter typeids.
for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
unsigned TypeID = FilterIds[j];
JCE->emitULEB128Bytes(TypeID);
//Asm->EOL("Filter TypeInfo index");
}
JCE->emitAlignmentWithFill(4, 0);
return DwarfExceptionTable;
}
unsigned char*
JITDwarfEmitter::EmitCommonEHFrame(const Function* Personality) const {
unsigned PointerSize = TD->getPointerSize();
int stackGrowth = stackGrowthDirection == TargetFrameLowering::StackGrowsUp ?
PointerSize : -PointerSize;
unsigned char* StartCommonPtr = (unsigned char*)JCE->getCurrentPCValue();
// EH Common Frame header
JCE->allocateSpace(4, 0);
unsigned char* FrameCommonBeginPtr = (unsigned char*)JCE->getCurrentPCValue();
JCE->emitInt32((int)0);
JCE->emitByte(dwarf::DW_CIE_VERSION);
JCE->emitString(Personality ? "zPLR" : "zR");
JCE->emitULEB128Bytes(1);
JCE->emitSLEB128Bytes(stackGrowth);
JCE->emitByte(RI->getDwarfRegNum(RI->getRARegister(), true));
if (Personality) {
// Augmentation Size: 3 small ULEBs of one byte each, and the personality
// function which size is PointerSize.
JCE->emitULEB128Bytes(3 + PointerSize);
// We set the encoding of the personality as direct encoding because we use
// the function pointer. The encoding is not relative because the current
// PC value may be bigger than the personality function pointer.
if (PointerSize == 4) {
JCE->emitByte(dwarf::DW_EH_PE_sdata4);
JCE->emitInt32(((intptr_t)Jit.getPointerToGlobal(Personality)));
} else {
JCE->emitByte(dwarf::DW_EH_PE_sdata8);
JCE->emitInt64(((intptr_t)Jit.getPointerToGlobal(Personality)));
}
// LSDA encoding: This must match the encoding used in EmitEHFrame ()
if (PointerSize == 4)
JCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
else
JCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8);
JCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
} else {
JCE->emitULEB128Bytes(1);
JCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
}
EmitFrameMoves(0, MAI->getInitialFrameState());
JCE->emitAlignmentWithFill(PointerSize, dwarf::DW_CFA_nop);
JCE->emitInt32At((uintptr_t*)StartCommonPtr,
(uintptr_t)((unsigned char*)JCE->getCurrentPCValue() -
FrameCommonBeginPtr));
return StartCommonPtr;
}
unsigned char*
JITDwarfEmitter::EmitEHFrame(const Function* Personality,
unsigned char* StartCommonPtr,
unsigned char* StartFunction,
unsigned char* EndFunction,
unsigned char* ExceptionTable) const {
unsigned PointerSize = TD->getPointerSize();
// EH frame header.
unsigned char* StartEHPtr = (unsigned char*)JCE->getCurrentPCValue();
JCE->allocateSpace(4, 0);
unsigned char* FrameBeginPtr = (unsigned char*)JCE->getCurrentPCValue();
// FDE CIE Offset
JCE->emitInt32(FrameBeginPtr - StartCommonPtr);
JCE->emitInt32(StartFunction - (unsigned char*)JCE->getCurrentPCValue());
JCE->emitInt32(EndFunction - StartFunction);
// If there is a personality and landing pads then point to the language
// specific data area in the exception table.
if (Personality) {
JCE->emitULEB128Bytes(PointerSize == 4 ? 4 : 8);
if (PointerSize == 4) {
if (!MMI->getLandingPads().empty())
JCE->emitInt32(ExceptionTable-(unsigned char*)JCE->getCurrentPCValue());
else
JCE->emitInt32((int)0);
} else {
if (!MMI->getLandingPads().empty())
JCE->emitInt64(ExceptionTable-(unsigned char*)JCE->getCurrentPCValue());
else
JCE->emitInt64((int)0);
}
} else {
JCE->emitULEB128Bytes(0);
}
// Indicate locations of function specific callee saved registers in
// frame.
EmitFrameMoves((intptr_t)StartFunction, MMI->getFrameMoves());
JCE->emitAlignmentWithFill(PointerSize, dwarf::DW_CFA_nop);
// Indicate the size of the table
JCE->emitInt32At((uintptr_t*)StartEHPtr,
(uintptr_t)((unsigned char*)JCE->getCurrentPCValue() -
StartEHPtr));
// Double zeroes for the unwind runtime
if (PointerSize == 8) {
JCE->emitInt64(0);
JCE->emitInt64(0);
} else {
JCE->emitInt32(0);
JCE->emitInt32(0);
}
return StartEHPtr;
}