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llvm-6502/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp
Chris Lattner 77beeaec1e remove the dwarf sizing stuff which is now dead, it was 
"yet another" copy of the dwarf EH emission code that was
copied, pasted and slightly hacked up.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109169 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-22 21:20:39 +00:00

598 lines
21 KiB
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//===----- 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/MachineLocation.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/ExecutionEngine/JITMemoryManager.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetFrameInfo.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.getFrameInfo()->getStackGrowthDirection();
RI = TM.getRegisterInfo();
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 == TargetFrameInfo::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->getDesc().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 == TargetFrameInfo::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);
}
std::vector<MachineMove> Moves;
RI->getInitialFrameState(Moves);
EmitFrameMoves(0, Moves);
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;
}
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