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This is the last major patch to implement support for the .loc directive

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and output the dwarf line number tables.  This contains the code to emit and
encode the dwarf line tables from the previously gathered information in the
MCLineSection objects.  This contains all the details to encode the line and
address deltas into the dwarf line table.

To do this an MCDwarfLineAddrFragment has been added.

Also this moves the interface code out of Mach-O streamer into
MCDwarf so it should be useable by other object file formats.

There is now one call to be made from an MCObjectStreamer
EmitInstruction() method:
   MCLineEntry::Make(this, getCurrentSection());
to create a line entry after each instruction is assembled.

And one call call to be made from an MCObjectStreamer Finish() method:
   MCDwarfFileTable::Emit(this, DwarfLineSection);
when getContext().hasDwarfFiles() is true and is passed a object file specific
MCSection where to emit the dwarf file and the line tables.

This appears to now be correct for 32-bit targets, at least x86.  But the
relocation entries for 64-bit Darwin needs some further work which is next
up to work on.  So for now the 64-bit Mach-O target does not output the
dwarf file and line tables.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115157 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Kevin Enderby 2010-09-30 16:52:03 +00:00
parent 9ee4aed3b6
commit c095793b4a
6 changed files with 571 additions and 206 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
lib/MC/MCAssembler.cpp
View File

@ -13,8 +13,10 @@
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringExtras.h"
@ -349,6 +351,20 @@ uint64_t MCAssembler::ComputeFragmentSize(MCAsmLayout &Layout,
return Offset;
}
case MCFragment::FT_Dwarf: {
const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
// The AddrDelta is really unsigned and it can only increase.
int64_t AddrDelta;
OF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, &Layout);
int64_t LineDelta;
LineDelta = OF.getLineDelta();
return MCDwarfLineAddr::ComputeSize(LineDelta, AddrDelta);
}
}
assert(0 && "invalid fragment kind");
@ -506,6 +522,20 @@ static void WriteFragmentData(const MCAssembler &Asm, const MCAsmLayout &Layout,
break;
}
case MCFragment::FT_Dwarf: {
const MCDwarfLineAddrFragment &OF = cast<MCDwarfLineAddrFragment>(F);
// The AddrDelta is really unsigned and it can only increase.
int64_t AddrDelta;
OF.getAddrDelta().EvaluateAsAbsolute(AddrDelta, &Layout);
int64_t LineDelta;
LineDelta = OF.getLineDelta();
MCDwarfLineAddr::Write(OW, LineDelta, (uint64_t)AddrDelta);
break;
}
}
assert(OW->getStream().tell() - Start == FragmentSize);
@ -872,6 +902,7 @@ void MCFragment::dump() {
case MCFragment::FT_Fill: OS << "MCFillFragment"; break;
case MCFragment::FT_Inst: OS << "MCInstFragment"; break;
case MCFragment::FT_Org: OS << "MCOrgFragment"; break;
case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break;
}
OS << "<MCFragment " << (void*) this << " LayoutOrder:" << LayoutOrder
@ -932,6 +963,13 @@ void MCFragment::dump() {
OS << " Offset:" << OF->getOffset() << " Value:" << OF->getValue();
break;
}
case MCFragment::FT_Dwarf: {
const MCDwarfLineAddrFragment *OF = cast<MCDwarfLineAddrFragment>(this);
OS << "\n ";
OS << " AddrDelta:" << OF->getAddrDelta()
<< " LineDelta:" << OF->getLineDelta();
break;
}
}
OS << ">";
}

469
lib/MC/MCDwarf.cpp
View File

@ -8,10 +8,478 @@
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetAsmBackend.h"
using namespace llvm;
// Given a special op, return the address skip amount (in units of
// DWARF2_LINE_MIN_INSN_LENGTH.
#define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
// The maximum address skip amount that can be encoded with a special op.
#define MAX_SPECIAL_ADDR_DELTA SPECIAL_ADDR(255)
// First special line opcode - leave room for the standard opcodes.
// Note: If you want to change this, you'll have to update the
// "standard_opcode_lengths" table that is emitted in DwarfFileTable::Emit().
#define DWARF2_LINE_OPCODE_BASE 13
// Minimum line offset in a special line info. opcode. This value
// was chosen to give a reasonable range of values.
#define DWARF2_LINE_BASE -5
// Range of line offsets in a special line info. opcode.
# define DWARF2_LINE_RANGE 14
// Define the architecture-dependent minimum instruction length (in bytes).
// This value should be rather too small than too big.
# define DWARF2_LINE_MIN_INSN_LENGTH 1
// Note: when DWARF2_LINE_MIN_INSN_LENGTH == 1 which is the current setting,
// this routine is a nop and will be optimized away.
static inline uint64_t ScaleAddrDelta(uint64_t AddrDelta)
{
if (DWARF2_LINE_MIN_INSN_LENGTH == 1)
return AddrDelta;
if (AddrDelta % DWARF2_LINE_MIN_INSN_LENGTH != 0) {
// TODO: report this error, but really only once.
;
}
return AddrDelta / DWARF2_LINE_MIN_INSN_LENGTH;
}
//
// This is called when an instruction is assembled into the specified section
// and if there is information from the last .loc directive that has yet to have
// a line entry made for it is made.
//
void MCLineEntry::Make(MCObjectStreamer *MCOS, const MCSection *Section) {
if (!MCOS->getContext().getDwarfLocSeen())
return;
// Create a symbol at in the current section for use in the line entry.
MCSymbol *LineSym = MCOS->getContext().CreateTempSymbol();
// Set the value of the symbol to use for the MCLineEntry.
MCOS->EmitLabel(LineSym);
// Get the current .loc info saved in the context.
const MCDwarfLoc &DwarfLoc = MCOS->getContext().getCurrentDwarfLoc();
// Create a (local) line entry with the symbol and the current .loc info.
MCLineEntry LineEntry(LineSym, DwarfLoc);
// clear DwarfLocSeen saying the current .loc info is now used.
MCOS->getContext().clearDwarfLocSeen();
// Get the MCLineSection for this section, if one does not exist for this
// section create it.
DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
MCOS->getContext().getMCLineSections();
MCLineSection *LineSection = MCLineSections[Section];
if (!LineSection) {
// Create a new MCLineSection. This will be deleted after the dwarf line
// table is created using it by iterating through the MCLineSections
// DenseMap.
LineSection = new MCLineSection;
// Save a pointer to the new LineSection into the MCLineSections DenseMap.
MCLineSections[Section] = LineSection;
}
// Add the line entry to this section's entries.
LineSection->addLineEntry(LineEntry);
}
//
// This helper routine returns an expression of End - Start + IntVal .
//
static inline const MCExpr *MakeStartMinusEndExpr(MCObjectStreamer *MCOS,
MCSymbol *Start,
MCSymbol *End, int IntVal) {
MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
const MCExpr *Res =
MCSymbolRefExpr::Create(End, Variant, MCOS->getContext());
const MCExpr *RHS =
MCSymbolRefExpr::Create(Start, Variant, MCOS->getContext());
const MCExpr *Res1 =
MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS, MCOS->getContext());
const MCExpr *Res2 =
MCConstantExpr::Create(IntVal, MCOS->getContext());
const MCExpr *Res3 =
MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, MCOS->getContext());
return Res3;
}
//
// This emits an "absolute" address used in the start of a dwarf line number
// table. This will result in a relocatation entry for the address.
//
static inline void EmitDwarfSetAddress(MCObjectStreamer *MCOS,
MCSymbol *Symbol) {
MCOS->EmitIntValue(dwarf::DW_LNS_extended_op, 1);
int sizeof_address = MCOS->getAssembler().getBackend().getPointerSize();
MCOS->EmitULEB128Value(sizeof_address + 1);
MCOS->EmitIntValue(dwarf::DW_LNE_set_address, 1);
MCOS->EmitSymbolValue(Symbol, sizeof_address);
}
//
// This emits the Dwarf line table for the specified section from the entries
// in the LineSection.
//
static inline bool EmitDwarfLineTable(MCObjectStreamer *MCOS,
const MCSection *Section,
MCLineSection *LineSection,
const MCSection *DwarfLineSection) {
unsigned FileNum = 1;
unsigned LastLine = 1;
unsigned Column = 0;
unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
unsigned Isa = 0;
bool EmittedLineTable = false;
MCSymbol *LastLabel = NULL;
MCSectionData &DLS =
MCOS->getAssembler().getOrCreateSectionData(*DwarfLineSection);
// Loop through each MCLineEntry and encode the dwarf line number table.
for (MCLineSection::iterator
it = LineSection->getMCLineEntries()->begin(),
ie = LineSection->getMCLineEntries()->end(); it != ie; ++it) {
if (FileNum != it->getFileNum()) {
FileNum = it->getFileNum();
MCOS->EmitIntValue(dwarf::DW_LNS_set_file, 1);
MCOS->EmitULEB128Value(FileNum);
}
if (Column != it->getColumn()) {
Column = it->getColumn();
MCOS->EmitIntValue(dwarf::DW_LNS_set_column, 1);
MCOS->EmitULEB128Value(Column);
}
if (Isa != it->getIsa()) {
Isa = it->getIsa();
MCOS->EmitIntValue(dwarf::DW_LNS_set_isa, 1);
MCOS->EmitULEB128Value(Isa);
}
if ((it->getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
Flags = it->getFlags();
MCOS->EmitIntValue(dwarf::DW_LNS_negate_stmt, 1);
}
if (it->getFlags() & DWARF2_FLAG_BASIC_BLOCK)
MCOS->EmitIntValue(dwarf::DW_LNS_set_basic_block, 1);
if (it->getFlags() & DWARF2_FLAG_PROLOGUE_END)
MCOS->EmitIntValue(dwarf::DW_LNS_set_prologue_end, 1);
if (it->getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
MCOS->EmitIntValue(dwarf::DW_LNS_set_epilogue_begin, 1);
int64_t LineDelta = it->getLine() - LastLine;
MCSymbol *Label = it->getLabel();
// At this point we want to emit/create the sequence to encode the delta in
// line numbers and the increment of the address from the previous Label
// and the current Label.
if (LastLabel == NULL) {
// emit the sequence to set the address
EmitDwarfSetAddress(MCOS, Label);
// emit the sequence for the LineDelta (from 1) and a zero address delta.
MCDwarfLineAddr::Emit(MCOS, LineDelta, 0);
}
else {
// Create an expression for the address delta from the LastLabel and
// this Label (plus 0).
const MCExpr *AddrDelta = MakeStartMinusEndExpr(MCOS, LastLabel, Label,0);
// Create a Dwarf Line fragment for the LineDelta and AddrDelta.
new MCDwarfLineAddrFragment(LineDelta, *AddrDelta, &DLS);
}
LastLine = it->getLine();
LastLabel = Label;
EmittedLineTable = true;
}
// Emit a DW_LNE_end_sequence for the end of the section.
// Using the pointer Section create a temporary label at the end of the
// section and use that and the LastLabel to compute the address delta
// and use INT64_MAX as the line delta which is the signal that this is
// actually a DW_LNE_end_sequence.
// Switch to the section to be able to create a symbol at its end.
MCOS->SwitchSection(Section);
// Create a symbol at the end of the section.
MCSymbol *SectionEnd = MCOS->getContext().CreateTempSymbol();
// Set the value of the symbol, as we are at the end of the section.
MCOS->EmitLabel(SectionEnd);
// Switch back the the dwarf line section.
MCOS->SwitchSection(DwarfLineSection);
// Create an expression for the address delta from the LastLabel and this
// SectionEnd label.
const MCExpr *AddrDelta = MakeStartMinusEndExpr(MCOS, LastLabel, SectionEnd,
0);
// Create a Dwarf Line fragment for the LineDelta and AddrDelta.
new MCDwarfLineAddrFragment(INT64_MAX, *AddrDelta, &DLS);
return EmittedLineTable;
}
//
// This emits the Dwarf file and the line tables.
//
void MCDwarfFileTable::Emit(MCObjectStreamer *MCOS,
const MCSection *DwarfLineSection) {
// Switch to the section where the table will be emitted into.
MCOS->SwitchSection(DwarfLineSection);
// Create a symbol at the beginning of this section.
MCSymbol *LineStartSym = MCOS->getContext().CreateTempSymbol();
// Set the value of the symbol, as we are at the start of the section.
MCOS->EmitLabel(LineStartSym);
// Create a symbol for the end of the section (to be set when we get there).
MCSymbol *LineEndSym = MCOS->getContext().CreateTempSymbol();
// The first 4 bytes is the total length of the information for this
// compilation unit (not including these 4 bytes for the length).
MCOS->EmitValue(MakeStartMinusEndExpr(MCOS, LineStartSym, LineEndSym, 4),
4, 0);
// Next 2 bytes is the Version, which is Dwarf 2.
MCOS->EmitIntValue(2, 2);
// Create a symbol for the end of the prologue (to be set when we get there).
MCSymbol *ProEndSym = MCOS->getContext().CreateTempSymbol(); // Lprologue_end
// Length of the prologue, is the next 4 bytes. Which is the start of the
// section to the end of the prologue. Not including the 4 bytes for the
// total length, the 2 bytes for the version, and these 4 bytes for the
// length of the prologue.
MCOS->EmitValue(MakeStartMinusEndExpr(MCOS, LineStartSym, ProEndSym,
(4 + 2 + 4)),
4, 0);
// Parameters of the state machine, are next.
MCOS->EmitIntValue(DWARF2_LINE_MIN_INSN_LENGTH, 1);
MCOS->EmitIntValue(DWARF2_LINE_DEFAULT_IS_STMT, 1);
MCOS->EmitIntValue(DWARF2_LINE_BASE, 1);
MCOS->EmitIntValue(DWARF2_LINE_RANGE, 1);
MCOS->EmitIntValue(DWARF2_LINE_OPCODE_BASE, 1);
// Standard opcode lengths
MCOS->EmitIntValue(0, 1); // length of DW_LNS_copy
MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_pc
MCOS->EmitIntValue(1, 1); // length of DW_LNS_advance_line
MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_file
MCOS->EmitIntValue(1, 1); // length of DW_LNS_set_column
MCOS->EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
MCOS->EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
MCOS->EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
MCOS->EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
MCOS->EmitIntValue(1, 1); // DW_LNS_set_isa
// Put out the directory and file tables.
// First the directory table.
const std::vector<StringRef> &MCDwarfDirs =
MCOS->getContext().getMCDwarfDirs();
for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
MCOS->EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
}
MCOS->EmitIntValue(0, 1); // Terminate the directory list
// Second the file table.
const std::vector<MCDwarfFile *> &MCDwarfFiles =
MCOS->getContext().getMCDwarfFiles();
for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
MCOS->EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
MCOS->EmitBytes(StringRef("\0", 1), 0); // the null term. of the string
MCOS->EmitULEB128Value(MCDwarfFiles[i]->getDirIndex()); // the Directory num
MCOS->EmitIntValue(0, 1); // last modification timestamp (always 0)
MCOS->EmitIntValue(0, 1); // filesize (always 0)
}
MCOS->EmitIntValue(0, 1); // Terminate the file list
// This is the end of the prologue, so set the value of the symbol at the
// end of the prologue (that was used in a previous expression).
MCOS->EmitLabel(ProEndSym);
// Put out the line tables.
bool EmittedLineTable = false;
DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
MCOS->getContext().getMCLineSections();
for (DenseMap<const MCSection *, MCLineSection *>::iterator it =
MCLineSections.begin(), ie = MCLineSections.end(); it != ie; ++it) {
EmittedLineTable = EmitDwarfLineTable(MCOS, it->first, it->second,
DwarfLineSection);
// Now delete the MCLineSections that were created in MCLineEntry::Make()
// and used to emit the line table.
delete it->second;
}
// If there are no line tables emited then we emit:
// The following DW_LNE_set_address sequence to set the address to zero and
// the DW_LNE_end_sequence.
if (EmittedLineTable == false) {
if (MCOS->getAssembler().getBackend().getPointerSize() == 8) {
// This is the DW_LNE_set_address sequence for 64-bit code.
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(9, 1);
MCOS->EmitIntValue(2, 1);
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(0, 1);
}
else {
// This is the DW_LNE_set_address sequence for 32-bit code.
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(5, 1);
MCOS->EmitIntValue(2, 1);
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(0, 1);
MCOS->EmitIntValue(0, 1);
}
// Lastly emit the DW_LNE_end_sequence which consists of 3 bytes '00 01 01'
// (00 is the code for extended opcodes, followed by a ULEB128 length of the
// extended opcode (01), and the DW_LNE_end_sequence (01).
MCOS->EmitIntValue(0, 1); // DW_LNS_extended_op
MCOS->EmitIntValue(1, 1); // ULEB128 length of the extended opcode
MCOS->EmitIntValue(1, 1); // DW_LNE_end_sequence
}
// This is the end of the section, so set the value of the symbol at the end
// of this section (that was used in a previous expression).
MCOS->EmitLabel(LineEndSym);
}
/// Utility function to compute the size of the encoding.
uint64_t MCDwarfLineAddr::ComputeSize(int64_t LineDelta, uint64_t AddrDelta) {
SmallString<256> Tmp;
raw_svector_ostream OS(Tmp);
MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
return OS.GetNumBytesInBuffer();
}
/// Utility function to write the encoding to an object writer.
void MCDwarfLineAddr::Write(MCObjectWriter *OW, int64_t LineDelta,
uint64_t AddrDelta) {
SmallString<256> Tmp;
raw_svector_ostream OS(Tmp);
MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
OW->WriteBytes(OS.str());
}
/// Utility function to emit the encoding to a streamer.
void MCDwarfLineAddr::Emit(MCObjectStreamer *MCOS, int64_t LineDelta,
uint64_t AddrDelta) {
SmallString<256> Tmp;
raw_svector_ostream OS(Tmp);
MCDwarfLineAddr::Encode(LineDelta, AddrDelta, OS);
MCOS->EmitBytes(OS.str(), /*AddrSpace=*/0);
}
/// Utility function to encode a Dwarf pair of LineDelta and AddrDeltas.
void MCDwarfLineAddr::Encode(int64_t LineDelta, uint64_t AddrDelta,
raw_ostream &OS) {
uint64_t Temp, Opcode;
bool NeedCopy = false;
// Scale the address delta by the minimum instruction length.
AddrDelta = ScaleAddrDelta(AddrDelta);
// A LineDelta of INT64_MAX is a signal that this is actually a
// DW_LNE_end_sequence. We cannot use special opcodes here, since we want the
// end_sequence to emit the matrix entry.
if (LineDelta == INT64_MAX) {
if (AddrDelta == MAX_SPECIAL_ADDR_DELTA)
OS << char(dwarf::DW_LNS_const_add_pc);
else {
OS << char(dwarf::DW_LNS_advance_pc);
SmallString<32> Tmp;
raw_svector_ostream OSE(Tmp);
MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
OS << OSE.str();
}
OS << char(dwarf::DW_LNS_extended_op);
OS << char(1);
OS << char(dwarf::DW_LNE_end_sequence);
return;
}
// Bias the line delta by the base.
Temp = LineDelta - DWARF2_LINE_BASE;
// If the line increment is out of range of a special opcode, we must encode
// it with DW_LNS_advance_line.
if (Temp >= DWARF2_LINE_RANGE) {
OS << char(dwarf::DW_LNS_advance_line);
SmallString<32> Tmp;
raw_svector_ostream OSE(Tmp);
MCObjectWriter::EncodeSLEB128(LineDelta, OSE);
OS << OSE.str();
LineDelta = 0;
Temp = 0 - DWARF2_LINE_BASE;
NeedCopy = true;
}
// Use DW_LNS_copy instead of a "line +0, addr +0" special opcode.
if (LineDelta == 0 && AddrDelta == 0) {
OS << char(dwarf::DW_LNS_copy);
return;
}
// Bias the opcode by the special opcode base.
Temp += DWARF2_LINE_OPCODE_BASE;
// Avoid overflow when addr_delta is large.
if (AddrDelta < 256 + MAX_SPECIAL_ADDR_DELTA) {
// Try using a special opcode.
Opcode = Temp + AddrDelta * DWARF2_LINE_RANGE;
if (Opcode <= 255) {
OS << char(Opcode);
return;
}
// Try using DW_LNS_const_add_pc followed by special op.
Opcode = Temp + (AddrDelta - MAX_SPECIAL_ADDR_DELTA) * DWARF2_LINE_RANGE;
if (Opcode <= 255) {
OS << char(dwarf::DW_LNS_const_add_pc);
OS << char(Opcode);
return;
}
}
// Otherwise use DW_LNS_advance_pc.
OS << char(dwarf::DW_LNS_advance_pc);
SmallString<32> Tmp;
raw_svector_ostream OSE(Tmp);
MCObjectWriter::EncodeULEB128(AddrDelta, OSE);
OS << OSE.str();
if (NeedCopy)
OS << char(dwarf::DW_LNS_copy);
else
OS << char(Temp);
}
void MCDwarfFile::print(raw_ostream &OS) const {
OS << '"' << getName() << '"';
}
@ -19,3 +487,4 @@ void MCDwarfFile::print(raw_ostream &OS) const {
void MCDwarfFile::dump() const {
print(dbgs());
}

223
lib/MC/MCMachOStreamer.cpp
View File

@ -20,6 +20,7 @@
#include "llvm/MC/MCMachOSymbolFlags.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetAsmBackend.h"
@ -32,11 +33,6 @@ class MCMachOStreamer : public MCObjectStreamer {
private:
void EmitInstToFragment(const MCInst &Inst);
void EmitInstToData(const MCInst &Inst);
// FIXME: These will likely moved to a better place.
void MakeLineEntryForSection(const MCSection *Section);
const MCExpr * MakeStartMinusEndExpr(MCSymbol *Start, MCSymbol *End,
int IntVal);
void EmitDwarfFileTable(void);
public:
MCMachOStreamer(MCContext &Context, TargetAsmBackend &TAB,
@ -420,7 +416,7 @@ void MCMachOStreamer::EmitInstruction(const MCInst &Inst) {
// Now that a machine instruction has been assembled into this section, make
// a line entry for any .loc directive that has been seen.
MakeLineEntryForSection(getCurrentSection());
MCLineEntry::Make(this, getCurrentSection());
// If this instruction doesn't need relaxation, just emit it as data.
if (!getAssembler().getBackend().MayNeedRelaxation(Inst)) {
@ -443,206 +439,23 @@ void MCMachOStreamer::EmitInstruction(const MCInst &Inst) {
EmitInstToFragment(Inst);
}
//
// This is called when an instruction is assembled into the specified section
// and if there is information from the last .loc directive that has yet to have
// a line entry made for it is made.
//
void MCMachOStreamer::MakeLineEntryForSection(const MCSection *Section) {
if (!getContext().getDwarfLocSeen())
return;
// Create a symbol at in the current section for use in the line entry.
MCSymbol *LineSym = getContext().CreateTempSymbol();
// Set the value of the symbol to use for the MCLineEntry.
EmitLabel(LineSym);
// Get the current .loc info saved in the context.
const MCDwarfLoc &DwarfLoc = getContext().getCurrentDwarfLoc();
// Create a (local) line entry with the symbol and the current .loc info.
MCLineEntry LineEntry(LineSym, DwarfLoc);
// clear DwarfLocSeen saying the current .loc info is now used.
getContext().clearDwarfLocSeen();
// Get the MCLineSection for this section, if one does not exist for this
// section create it.
DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
getContext().getMCLineSections();
MCLineSection *LineSection = MCLineSections[Section];
if (!LineSection) {
// Create a new MCLineSection. This will be deleted after the dwarf line
// table is created using it by iterating through the MCLineSections
// DenseMap.
LineSection = new MCLineSection;
// Save a pointer to the new LineSection into the MCLineSections DenseMap.
MCLineSections[Section] = LineSection;
}
// Add the line entry to this section's entries.
LineSection->addLineEntry(LineEntry);
}
//
// This helper routine returns an expression of End - Start + IntVal for use
// by EmitDwarfFileTable() below.
//
const MCExpr * MCMachOStreamer::MakeStartMinusEndExpr(MCSymbol *Start,
MCSymbol *End,
int IntVal) {
MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
const MCExpr *Res =
MCSymbolRefExpr::Create(End, Variant, getContext());
const MCExpr *RHS =
MCSymbolRefExpr::Create(Start, Variant, getContext());
const MCExpr *Res1 =
MCBinaryExpr::Create(MCBinaryExpr::Sub, Res, RHS,getContext());
const MCExpr *Res2 =
MCConstantExpr::Create(IntVal, getContext());
const MCExpr *Res3 =
MCBinaryExpr::Create(MCBinaryExpr::Sub, Res1, Res2, getContext());
return Res3;
}
//
// This emits the Dwarf file (and eventually the line) table.
//
void MCMachOStreamer::EmitDwarfFileTable(void) {
// For now make sure we don't put out the Dwarf file table if no .file
// directives were seen.
const std::vector<MCDwarfFile *> &MCDwarfFiles =
getContext().getMCDwarfFiles();
if (MCDwarfFiles.size() == 0)
return;
// This is the Mach-O section, for ELF it is the .debug_line section.
SwitchSection(getContext().getMachOSection("__DWARF", "__debug_line",
MCSectionMachO::S_ATTR_DEBUG,
0, SectionKind::getDataRelLocal()));
// Create a symbol at the beginning of this section.
MCSymbol *LineStartSym = getContext().CreateTempSymbol();
// Set the value of the symbol, as we are at the start of the section.
EmitLabel(LineStartSym);
// Create a symbol for the end of the section (to be set when we get there).
MCSymbol *LineEndSym = getContext().CreateTempSymbol();
// The first 4 bytes is the total length of the information for this
// compilation unit (not including these 4 bytes for the length).
EmitValue(MakeStartMinusEndExpr(LineStartSym, LineEndSym, 4), 4, 0);
// Next 2 bytes is the Version, which is Dwarf 2.
EmitIntValue(2, 2);
// Create a symbol for the end of the prologue (to be set when we get there).
MCSymbol *ProEndSym = getContext().CreateTempSymbol(); // Lprologue_end
// Length of the prologue, is the next 4 bytes. Which is the start of the
// section to the end of the prologue. Not including the 4 bytes for the
// total length, the 2 bytes for the version, and these 4 bytes for the
// length of the prologue.
EmitValue(MakeStartMinusEndExpr(LineStartSym, ProEndSym, (4 + 2 + 4)), 4, 0);
// Parameters of the state machine, are next.
// Define the architecture-dependent minimum instruction length (in
// bytes). This value should be rather too small than too big. */
// DWARF2_LINE_MIN_INSN_LENGTH
EmitIntValue(1, 1);
// Flag that indicates the initial value of the is_stmt_start flag.
// DWARF2_LINE_DEFAULT_IS_STMT
EmitIntValue(1, 1);
// Minimum line offset in a special line info. opcode. This value
// was chosen to give a reasonable range of values. */
// DWARF2_LINE_BASE
EmitIntValue(uint64_t(-5), 1);
// Range of line offsets in a special line info. opcode.
// DWARF2_LINE_RANGE
EmitIntValue(14, 1);
// First special line opcode - leave room for the standard opcodes.
// DWARF2_LINE_OPCODE_BASE
EmitIntValue(13, 1);
// Standard opcode lengths
EmitIntValue(0, 1); // length of DW_LNS_copy
EmitIntValue(1, 1); // length of DW_LNS_advance_pc
EmitIntValue(1, 1); // length of DW_LNS_advance_line
EmitIntValue(1, 1); // length of DW_LNS_set_file
EmitIntValue(1, 1); // length of DW_LNS_set_column
EmitIntValue(0, 1); // length of DW_LNS_negate_stmt
EmitIntValue(0, 1); // length of DW_LNS_set_basic_block
EmitIntValue(0, 1); // length of DW_LNS_const_add_pc
EmitIntValue(1, 1); // length of DW_LNS_fixed_advance_pc
EmitIntValue(0, 1); // length of DW_LNS_set_prologue_end
EmitIntValue(0, 1); // length of DW_LNS_set_epilogue_begin
EmitIntValue(1, 1); // DW_LNS_set_isa
// Put out the directory and file tables.
// First the directory table.
const std::vector<StringRef> &MCDwarfDirs =
getContext().getMCDwarfDirs();
for (unsigned i = 0; i < MCDwarfDirs.size(); i++) {
EmitBytes(MCDwarfDirs[i], 0); // the DirectoryName
EmitBytes(StringRef("\0", 1), 0); // the null termination of the string
}
EmitIntValue(0, 1); // Terminate the directory list
// Second the file table.
for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
EmitBytes(MCDwarfFiles[i]->getName(), 0); // FileName
EmitBytes(StringRef("\0", 1), 0); // the null termination of the string
// FIXME the Directory number should be a .uleb128 not a .byte
EmitIntValue(MCDwarfFiles[i]->getDirIndex(), 1);
EmitIntValue(0, 1); // last modification timestamp (always 0)
EmitIntValue(0, 1); // filesize (always 0)
}
EmitIntValue(0, 1); // Terminate the file list
// This is the end of the prologue, so set the value of the symbol at the
// end of the prologue (that was used in a previous expression).
EmitLabel(ProEndSym);
// TODO: This is the point where the line tables would be emitted.
// Delete the MCLineSections that were created in
// MCMachOStreamer::MakeLineEntryForSection() and used to emit the line
// tables.
DenseMap<const MCSection *, MCLineSection *> &MCLineSections =
getContext().getMCLineSections();
for (DenseMap<const MCSection *, MCLineSection *>::iterator it =
MCLineSections.begin(), ie = MCLineSections.end(); it != ie; ++it) {
delete it->second;
}
// If there are no line tables emited then we emit:
// The following DW_LNE_set_address sequence to set the address to zero
// TODO test for 32-bit or 64-bit output
// This is the sequence for 32-bit code
EmitIntValue(0, 1);
EmitIntValue(5, 1);
EmitIntValue(2, 1);
EmitIntValue(0, 1);
EmitIntValue(0, 1);
EmitIntValue(0, 1);
EmitIntValue(0, 1);
// Lastly emit the DW_LNE_end_sequence which consists of 3 bytes '00 01 01'
// (00 is the code for extended opcodes, followed by a ULEB128 length of the
// extended opcode (01), and the DW_LNE_end_sequence (01).
EmitIntValue(0, 1); // DW_LNS_extended_op
EmitIntValue(1, 1); // ULEB128 length of the extended opcode
EmitIntValue(1, 1); // DW_LNE_end_sequence
// This is the end of the section, so set the value of the symbol at the end
// of this section (that was used in a previous expression).
EmitLabel(LineEndSym);
}
void MCMachOStreamer::Finish() {
// Dump out the dwarf file and directory tables (soon to include line table)
EmitDwarfFileTable();
// Dump out the dwarf file & directory tables and line tables.
if (getContext().hasDwarfFiles() &&
// TODO: This not enabled for 64-bit Mach-O targets. As there are needed
// changes in the handling of 64-bit relocation entries for dwarf Mach-O
// sections that need to made. Currently it gets
// LLVM ERROR: unsupported local relocations in difference
// due dealing with "a-b" expressions made up for dwarf line entries
// because the line section has no non-local symbols thus it can't find
// an atom symbol for the base.
getAssembler().getBackend().getPointerSize() != 8) {
const MCSection *DwarfLineSection = getContext().getMachOSection("__DWARF",
"__debug_line",
MCSectionMachO::S_ATTR_DEBUG,
0, SectionKind::getDataRelLocal());
MCDwarfFileTable::Emit(this, DwarfLineSection);
}
// We have to set the fragment atom associations so we can relax properly for
// Mach-O.

26
lib/MC/MCObjectWriter.cpp
View File

@ -13,3 +13,29 @@ using namespace llvm;
MCObjectWriter::~MCObjectWriter() {
}
/// Utility function to encode a SLEB128 value.
void MCObjectWriter::EncodeSLEB128(int64_t Value, raw_ostream &OS) {
bool More;
do {
uint8_t Byte = Value & 0x7f;
// NOTE: this assumes that this signed shift is an arithmetic right shift.
Value >>= 7;
More = !((((Value == 0 ) && ((Byte & 0x40) == 0)) ||
((Value == -1) && ((Byte & 0x40) != 0))));
if (More)
Byte |= 0x80; // Mark this byte that that more bytes will follow.
OS << char(Byte);
} while (More);
}
/// Utility function to encode a ULEB128 value.
void MCObjectWriter::EncodeULEB128(uint64_t Value, raw_ostream &OS) {
do {
uint8_t Byte = Value & 0x7f;
Value >>= 7;
if (Value != 0)
Byte |= 0x80; // Mark this byte that that more bytes will follow.
OS << char(Byte);
} while (Value != 0);
}

2
lib/MC/MCParser/AsmParser.cpp
View File

@ -2056,7 +2056,7 @@ bool GenericAsmParser::ParseDirectiveLoc(StringRef, SMLoc DirectiveLoc) {
Lex();
}
unsigned Flags = 0;
unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
unsigned Isa = 0;
if (getLexer().isNot(AsmToken::EndOfStatement)) {
for (;;) {

19
lib/MC/MCStreamer.cpp
View File

@ -9,6 +9,7 @@
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
@ -35,6 +36,24 @@ void MCStreamer::EmitIntValue(uint64_t Value, unsigned Size,
EmitValue(MCConstantExpr::Create(Value, getContext()), Size, AddrSpace);
}
// EmitULEB128Value - Special case of EmitValue that emits a ULEB128 of the
// Value as the sequence of ULEB128 encoded bytes.
void MCStreamer::EmitULEB128Value(uint64_t Value, unsigned AddrSpace) {
SmallString<32> Tmp;
raw_svector_ostream OS(Tmp);
MCObjectWriter::EncodeULEB128(Value, OS);
EmitBytes(OS.str(), AddrSpace);
}
// EmitSLEB128Value - Special case of EmitValue that emits a SLEB128 of the
// Value as the sequence of ULEB128 encoded bytes.
void MCStreamer::EmitSLEB128Value(int64_t Value, unsigned AddrSpace) {
SmallString<32> Tmp;
raw_svector_ostream OS(Tmp);
MCObjectWriter::EncodeSLEB128(Value, OS);
EmitBytes(OS.str(), AddrSpace);
}
void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
unsigned AddrSpace) {
EmitValue(MCSymbolRefExpr::Create(Sym, getContext()), Size, AddrSpace);