| //===- MCCodeView.h - Machine Code CodeView support -------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Holds state from .cv_file and .cv_loc directives for later emission. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/MC/MCCodeView.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/DebugInfo/CodeView/CodeView.h" |
| #include "llvm/DebugInfo/CodeView/Line.h" |
| #include "llvm/DebugInfo/CodeView/SymbolRecord.h" |
| #include "llvm/MC/MCAsmLayout.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCObjectStreamer.h" |
| #include "llvm/MC/MCValue.h" |
| #include "llvm/Support/EndianStream.h" |
| |
| using namespace llvm; |
| using namespace llvm::codeview; |
| |
| CodeViewContext::CodeViewContext() {} |
| |
| CodeViewContext::~CodeViewContext() { |
| // If someone inserted strings into the string table but never actually |
| // emitted them somewhere, clean up the fragment. |
| if (!InsertedStrTabFragment) |
| delete StrTabFragment; |
| } |
| |
| /// This is a valid number for use with .cv_loc if we've already seen a .cv_file |
| /// for it. |
| bool CodeViewContext::isValidFileNumber(unsigned FileNumber) const { |
| unsigned Idx = FileNumber - 1; |
| if (Idx < Files.size()) |
| return Files[Idx].Assigned; |
| return false; |
| } |
| |
| bool CodeViewContext::addFile(MCStreamer &OS, unsigned FileNumber, |
| StringRef Filename, |
| ArrayRef<uint8_t> ChecksumBytes, |
| uint8_t ChecksumKind) { |
| assert(FileNumber > 0); |
| auto FilenameOffset = addToStringTable(Filename); |
| Filename = FilenameOffset.first; |
| unsigned Idx = FileNumber - 1; |
| if (Idx >= Files.size()) |
| Files.resize(Idx + 1); |
| |
| if (Filename.empty()) |
| Filename = "<stdin>"; |
| |
| if (Files[Idx].Assigned) |
| return false; |
| |
| FilenameOffset = addToStringTable(Filename); |
| Filename = FilenameOffset.first; |
| unsigned Offset = FilenameOffset.second; |
| |
| auto ChecksumOffsetSymbol = |
| OS.getContext().createTempSymbol("checksum_offset", false); |
| Files[Idx].StringTableOffset = Offset; |
| Files[Idx].ChecksumTableOffset = ChecksumOffsetSymbol; |
| Files[Idx].Assigned = true; |
| Files[Idx].Checksum = ChecksumBytes; |
| Files[Idx].ChecksumKind = ChecksumKind; |
| |
| return true; |
| } |
| |
| MCCVFunctionInfo *CodeViewContext::getCVFunctionInfo(unsigned FuncId) { |
| if (FuncId >= Functions.size()) |
| return nullptr; |
| if (Functions[FuncId].isUnallocatedFunctionInfo()) |
| return nullptr; |
| return &Functions[FuncId]; |
| } |
| |
| bool CodeViewContext::recordFunctionId(unsigned FuncId) { |
| if (FuncId >= Functions.size()) |
| Functions.resize(FuncId + 1); |
| |
| // Return false if this function info was already allocated. |
| if (!Functions[FuncId].isUnallocatedFunctionInfo()) |
| return false; |
| |
| // Mark this as an allocated normal function, and leave the rest alone. |
| Functions[FuncId].ParentFuncIdPlusOne = MCCVFunctionInfo::FunctionSentinel; |
| return true; |
| } |
| |
| bool CodeViewContext::recordInlinedCallSiteId(unsigned FuncId, unsigned IAFunc, |
| unsigned IAFile, unsigned IALine, |
| unsigned IACol) { |
| if (FuncId >= Functions.size()) |
| Functions.resize(FuncId + 1); |
| |
| // Return false if this function info was already allocated. |
| if (!Functions[FuncId].isUnallocatedFunctionInfo()) |
| return false; |
| |
| MCCVFunctionInfo::LineInfo InlinedAt; |
| InlinedAt.File = IAFile; |
| InlinedAt.Line = IALine; |
| InlinedAt.Col = IACol; |
| |
| // Mark this as an inlined call site and record call site line info. |
| MCCVFunctionInfo *Info = &Functions[FuncId]; |
| Info->ParentFuncIdPlusOne = IAFunc + 1; |
| Info->InlinedAt = InlinedAt; |
| |
| // Walk up the call chain adding this function id to the InlinedAtMap of all |
| // transitive callers until we hit a real function. |
| while (Info->isInlinedCallSite()) { |
| InlinedAt = Info->InlinedAt; |
| Info = getCVFunctionInfo(Info->getParentFuncId()); |
| Info->InlinedAtMap[FuncId] = InlinedAt; |
| } |
| |
| return true; |
| } |
| |
| void CodeViewContext::recordCVLoc(MCContext &Ctx, const MCSymbol *Label, |
| unsigned FunctionId, unsigned FileNo, |
| unsigned Line, unsigned Column, |
| bool PrologueEnd, bool IsStmt) { |
| addLineEntry(MCCVLoc{ |
| Label, FunctionId, FileNo, Line, Column, PrologueEnd, IsStmt}); |
| } |
| |
| MCDataFragment *CodeViewContext::getStringTableFragment() { |
| if (!StrTabFragment) { |
| StrTabFragment = new MCDataFragment(); |
| // Start a new string table out with a null byte. |
| StrTabFragment->getContents().push_back('\0'); |
| } |
| return StrTabFragment; |
| } |
| |
| std::pair<StringRef, unsigned> CodeViewContext::addToStringTable(StringRef S) { |
| SmallVectorImpl<char> &Contents = getStringTableFragment()->getContents(); |
| auto Insertion = |
| StringTable.insert(std::make_pair(S, unsigned(Contents.size()))); |
| // Return the string from the table, since it is stable. |
| std::pair<StringRef, unsigned> Ret = |
| std::make_pair(Insertion.first->first(), Insertion.first->second); |
| if (Insertion.second) { |
| // The string map key is always null terminated. |
| Contents.append(Ret.first.begin(), Ret.first.end() + 1); |
| } |
| return Ret; |
| } |
| |
| unsigned CodeViewContext::getStringTableOffset(StringRef S) { |
| // A string table offset of zero is always the empty string. |
| if (S.empty()) |
| return 0; |
| auto I = StringTable.find(S); |
| assert(I != StringTable.end()); |
| return I->second; |
| } |
| |
| void CodeViewContext::emitStringTable(MCObjectStreamer &OS) { |
| MCContext &Ctx = OS.getContext(); |
| MCSymbol *StringBegin = Ctx.createTempSymbol("strtab_begin", false), |
| *StringEnd = Ctx.createTempSymbol("strtab_end", false); |
| |
| OS.EmitIntValue(unsigned(DebugSubsectionKind::StringTable), 4); |
| OS.emitAbsoluteSymbolDiff(StringEnd, StringBegin, 4); |
| OS.EmitLabel(StringBegin); |
| |
| // Put the string table data fragment here, if we haven't already put it |
| // somewhere else. If somebody wants two string tables in their .s file, one |
| // will just be empty. |
| if (!InsertedStrTabFragment) { |
| OS.insert(getStringTableFragment()); |
| InsertedStrTabFragment = true; |
| } |
| |
| OS.EmitValueToAlignment(4, 0); |
| |
| OS.EmitLabel(StringEnd); |
| } |
| |
| void CodeViewContext::emitFileChecksums(MCObjectStreamer &OS) { |
| // Do nothing if there are no file checksums. Microsoft's linker rejects empty |
| // CodeView substreams. |
| if (Files.empty()) |
| return; |
| |
| MCContext &Ctx = OS.getContext(); |
| MCSymbol *FileBegin = Ctx.createTempSymbol("filechecksums_begin", false), |
| *FileEnd = Ctx.createTempSymbol("filechecksums_end", false); |
| |
| OS.EmitIntValue(unsigned(DebugSubsectionKind::FileChecksums), 4); |
| OS.emitAbsoluteSymbolDiff(FileEnd, FileBegin, 4); |
| OS.EmitLabel(FileBegin); |
| |
| unsigned CurrentOffset = 0; |
| |
| // Emit an array of FileChecksum entries. We index into this table using the |
| // user-provided file number. Each entry may be a variable number of bytes |
| // determined by the checksum kind and size. |
| for (auto File : Files) { |
| OS.EmitAssignment(File.ChecksumTableOffset, |
| MCConstantExpr::create(CurrentOffset, Ctx)); |
| CurrentOffset += 4; // String table offset. |
| if (!File.ChecksumKind) { |
| CurrentOffset += |
| 4; // One byte each for checksum size and kind, then align to 4 bytes. |
| } else { |
| CurrentOffset += 2; // One byte each for checksum size and kind. |
| CurrentOffset += File.Checksum.size(); |
| CurrentOffset = alignTo(CurrentOffset, 4); |
| } |
| |
| OS.EmitIntValue(File.StringTableOffset, 4); |
| |
| if (!File.ChecksumKind) { |
| // There is no checksum. Therefore zero the next two fields and align |
| // back to 4 bytes. |
| OS.EmitIntValue(0, 4); |
| continue; |
| } |
| OS.EmitIntValue(static_cast<uint8_t>(File.Checksum.size()), 1); |
| OS.EmitIntValue(File.ChecksumKind, 1); |
| OS.EmitBytes(toStringRef(File.Checksum)); |
| OS.EmitValueToAlignment(4); |
| } |
| |
| OS.EmitLabel(FileEnd); |
| |
| ChecksumOffsetsAssigned = true; |
| } |
| |
| // Output checksum table offset of the given file number. It is possible that |
| // not all files have been registered yet, and so the offset cannot be |
| // calculated. In this case a symbol representing the offset is emitted, and |
| // the value of this symbol will be fixed up at a later time. |
| void CodeViewContext::emitFileChecksumOffset(MCObjectStreamer &OS, |
| unsigned FileNo) { |
| unsigned Idx = FileNo - 1; |
| |
| if (Idx >= Files.size()) |
| Files.resize(Idx + 1); |
| |
| if (ChecksumOffsetsAssigned) { |
| OS.EmitSymbolValue(Files[Idx].ChecksumTableOffset, 4); |
| return; |
| } |
| |
| const MCSymbolRefExpr *SRE = |
| MCSymbolRefExpr::create(Files[Idx].ChecksumTableOffset, OS.getContext()); |
| |
| OS.EmitValueImpl(SRE, 4); |
| } |
| |
| void CodeViewContext::addLineEntry(const MCCVLoc &LineEntry) { |
| size_t Offset = MCCVLines.size(); |
| auto I = MCCVLineStartStop.insert( |
| {LineEntry.getFunctionId(), {Offset, Offset + 1}}); |
| if (!I.second) |
| I.first->second.second = Offset + 1; |
| MCCVLines.push_back(LineEntry); |
| } |
| |
| std::vector<MCCVLoc> |
| CodeViewContext::getFunctionLineEntries(unsigned FuncId) { |
| std::vector<MCCVLoc> FilteredLines; |
| auto I = MCCVLineStartStop.find(FuncId); |
| if (I != MCCVLineStartStop.end()) { |
| MCCVFunctionInfo *SiteInfo = getCVFunctionInfo(FuncId); |
| for (size_t Idx = I->second.first, End = I->second.second; Idx != End; |
| ++Idx) { |
| unsigned LocationFuncId = MCCVLines[Idx].getFunctionId(); |
| if (LocationFuncId == FuncId) { |
| // This was a .cv_loc directly for FuncId, so record it. |
| FilteredLines.push_back(MCCVLines[Idx]); |
| } else { |
| // Check if the current location is inlined in this function. If it is, |
| // synthesize a statement .cv_loc at the original inlined call site. |
| auto I = SiteInfo->InlinedAtMap.find(LocationFuncId); |
| if (I != SiteInfo->InlinedAtMap.end()) { |
| MCCVFunctionInfo::LineInfo &IA = I->second; |
| // Only add the location if it differs from the previous location. |
| // Large inlined calls will have many .cv_loc entries and we only need |
| // one line table entry in the parent function. |
| if (FilteredLines.empty() || |
| FilteredLines.back().getFileNum() != IA.File || |
| FilteredLines.back().getLine() != IA.Line || |
| FilteredLines.back().getColumn() != IA.Col) { |
| FilteredLines.push_back(MCCVLoc( |
| MCCVLines[Idx].getLabel(), |
| FuncId, IA.File, IA.Line, IA.Col, false, false)); |
| } |
| } |
| } |
| } |
| } |
| return FilteredLines; |
| } |
| |
| std::pair<size_t, size_t> CodeViewContext::getLineExtent(unsigned FuncId) { |
| auto I = MCCVLineStartStop.find(FuncId); |
| // Return an empty extent if there are no cv_locs for this function id. |
| if (I == MCCVLineStartStop.end()) |
| return {~0ULL, 0}; |
| return I->second; |
| } |
| |
| ArrayRef<MCCVLoc> CodeViewContext::getLinesForExtent(size_t L, size_t R) { |
| if (R <= L) |
| return None; |
| if (L >= MCCVLines.size()) |
| return None; |
| return makeArrayRef(&MCCVLines[L], R - L); |
| } |
| |
| void CodeViewContext::emitLineTableForFunction(MCObjectStreamer &OS, |
| unsigned FuncId, |
| const MCSymbol *FuncBegin, |
| const MCSymbol *FuncEnd) { |
| MCContext &Ctx = OS.getContext(); |
| MCSymbol *LineBegin = Ctx.createTempSymbol("linetable_begin", false), |
| *LineEnd = Ctx.createTempSymbol("linetable_end", false); |
| |
| OS.EmitIntValue(unsigned(DebugSubsectionKind::Lines), 4); |
| OS.emitAbsoluteSymbolDiff(LineEnd, LineBegin, 4); |
| OS.EmitLabel(LineBegin); |
| OS.EmitCOFFSecRel32(FuncBegin, /*Offset=*/0); |
| OS.EmitCOFFSectionIndex(FuncBegin); |
| |
| // Actual line info. |
| std::vector<MCCVLoc> Locs = getFunctionLineEntries(FuncId); |
| bool HaveColumns = any_of(Locs, [](const MCCVLoc &LineEntry) { |
| return LineEntry.getColumn() != 0; |
| }); |
| OS.EmitIntValue(HaveColumns ? int(LF_HaveColumns) : 0, 2); |
| OS.emitAbsoluteSymbolDiff(FuncEnd, FuncBegin, 4); |
| |
| for (auto I = Locs.begin(), E = Locs.end(); I != E;) { |
| // Emit a file segment for the run of locations that share a file id. |
| unsigned CurFileNum = I->getFileNum(); |
| auto FileSegEnd = |
| std::find_if(I, E, [CurFileNum](const MCCVLoc &Loc) { |
| return Loc.getFileNum() != CurFileNum; |
| }); |
| unsigned EntryCount = FileSegEnd - I; |
| OS.AddComment( |
| "Segment for file '" + |
| Twine(getStringTableFragment() |
| ->getContents()[Files[CurFileNum - 1].StringTableOffset]) + |
| "' begins"); |
| OS.EmitCVFileChecksumOffsetDirective(CurFileNum); |
| OS.EmitIntValue(EntryCount, 4); |
| uint32_t SegmentSize = 12; |
| SegmentSize += 8 * EntryCount; |
| if (HaveColumns) |
| SegmentSize += 4 * EntryCount; |
| OS.EmitIntValue(SegmentSize, 4); |
| |
| for (auto J = I; J != FileSegEnd; ++J) { |
| OS.emitAbsoluteSymbolDiff(J->getLabel(), FuncBegin, 4); |
| unsigned LineData = J->getLine(); |
| if (J->isStmt()) |
| LineData |= LineInfo::StatementFlag; |
| OS.EmitIntValue(LineData, 4); |
| } |
| if (HaveColumns) { |
| for (auto J = I; J != FileSegEnd; ++J) { |
| OS.EmitIntValue(J->getColumn(), 2); |
| OS.EmitIntValue(0, 2); |
| } |
| } |
| I = FileSegEnd; |
| } |
| OS.EmitLabel(LineEnd); |
| } |
| |
| static bool compressAnnotation(uint32_t Data, SmallVectorImpl<char> &Buffer) { |
| if (isUInt<7>(Data)) { |
| Buffer.push_back(Data); |
| return true; |
| } |
| |
| if (isUInt<14>(Data)) { |
| Buffer.push_back((Data >> 8) | 0x80); |
| Buffer.push_back(Data & 0xff); |
| return true; |
| } |
| |
| if (isUInt<29>(Data)) { |
| Buffer.push_back((Data >> 24) | 0xC0); |
| Buffer.push_back((Data >> 16) & 0xff); |
| Buffer.push_back((Data >> 8) & 0xff); |
| Buffer.push_back(Data & 0xff); |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static bool compressAnnotation(BinaryAnnotationsOpCode Annotation, |
| SmallVectorImpl<char> &Buffer) { |
| return compressAnnotation(static_cast<uint32_t>(Annotation), Buffer); |
| } |
| |
| static uint32_t encodeSignedNumber(uint32_t Data) { |
| if (Data >> 31) |
| return ((-Data) << 1) | 1; |
| return Data << 1; |
| } |
| |
| void CodeViewContext::emitInlineLineTableForFunction(MCObjectStreamer &OS, |
| unsigned PrimaryFunctionId, |
| unsigned SourceFileId, |
| unsigned SourceLineNum, |
| const MCSymbol *FnStartSym, |
| const MCSymbol *FnEndSym) { |
| // Create and insert a fragment into the current section that will be encoded |
| // later. |
| new MCCVInlineLineTableFragment(PrimaryFunctionId, SourceFileId, |
| SourceLineNum, FnStartSym, FnEndSym, |
| OS.getCurrentSectionOnly()); |
| } |
| |
| MCFragment *CodeViewContext::emitDefRange( |
| MCObjectStreamer &OS, |
| ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges, |
| StringRef FixedSizePortion) { |
| // Create and insert a fragment into the current section that will be encoded |
| // later. |
| return new MCCVDefRangeFragment(Ranges, FixedSizePortion, |
| OS.getCurrentSectionOnly()); |
| } |
| |
| static unsigned computeLabelDiff(MCAsmLayout &Layout, const MCSymbol *Begin, |
| const MCSymbol *End) { |
| MCContext &Ctx = Layout.getAssembler().getContext(); |
| MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None; |
| const MCExpr *BeginRef = MCSymbolRefExpr::create(Begin, Variant, Ctx), |
| *EndRef = MCSymbolRefExpr::create(End, Variant, Ctx); |
| const MCExpr *AddrDelta = |
| MCBinaryExpr::create(MCBinaryExpr::Sub, EndRef, BeginRef, Ctx); |
| int64_t Result; |
| bool Success = AddrDelta->evaluateKnownAbsolute(Result, Layout); |
| assert(Success && "failed to evaluate label difference as absolute"); |
| (void)Success; |
| assert(Result >= 0 && "negative label difference requested"); |
| assert(Result < UINT_MAX && "label difference greater than 2GB"); |
| return unsigned(Result); |
| } |
| |
| void CodeViewContext::encodeInlineLineTable(MCAsmLayout &Layout, |
| MCCVInlineLineTableFragment &Frag) { |
| size_t LocBegin; |
| size_t LocEnd; |
| std::tie(LocBegin, LocEnd) = getLineExtent(Frag.SiteFuncId); |
| |
| // Include all child inline call sites in our .cv_loc extent. |
| MCCVFunctionInfo *SiteInfo = getCVFunctionInfo(Frag.SiteFuncId); |
| for (auto &KV : SiteInfo->InlinedAtMap) { |
| unsigned ChildId = KV.first; |
| auto Extent = getLineExtent(ChildId); |
| LocBegin = std::min(LocBegin, Extent.first); |
| LocEnd = std::max(LocEnd, Extent.second); |
| } |
| |
| if (LocBegin >= LocEnd) |
| return; |
| ArrayRef<MCCVLoc> Locs = getLinesForExtent(LocBegin, LocEnd); |
| if (Locs.empty()) |
| return; |
| |
| // Check that the locations are all in the same section. |
| #ifndef NDEBUG |
| const MCSection *FirstSec = &Locs.front().getLabel()->getSection(); |
| for (const MCCVLoc &Loc : Locs) { |
| if (&Loc.getLabel()->getSection() != FirstSec) { |
| errs() << ".cv_loc " << Loc.getFunctionId() << ' ' << Loc.getFileNum() |
| << ' ' << Loc.getLine() << ' ' << Loc.getColumn() |
| << " is in the wrong section\n"; |
| llvm_unreachable(".cv_loc crosses sections"); |
| } |
| } |
| #endif |
| |
| // Make an artificial start location using the function start and the inlinee |
| // lines start location information. All deltas start relative to this |
| // location. |
| MCCVLoc StartLoc = Locs.front(); |
| StartLoc.setLabel(Frag.getFnStartSym()); |
| StartLoc.setFileNum(Frag.StartFileId); |
| StartLoc.setLine(Frag.StartLineNum); |
| bool HaveOpenRange = false; |
| |
| const MCSymbol *LastLabel = Frag.getFnStartSym(); |
| MCCVFunctionInfo::LineInfo LastSourceLoc, CurSourceLoc; |
| LastSourceLoc.File = Frag.StartFileId; |
| LastSourceLoc.Line = Frag.StartLineNum; |
| |
| SmallVectorImpl<char> &Buffer = Frag.getContents(); |
| Buffer.clear(); // Clear old contents if we went through relaxation. |
| for (const MCCVLoc &Loc : Locs) { |
| // Exit early if our line table would produce an oversized InlineSiteSym |
| // record. Account for the ChangeCodeLength annotation emitted after the |
| // loop ends. |
| constexpr uint32_t InlineSiteSize = 12; |
| constexpr uint32_t AnnotationSize = 8; |
| size_t MaxBufferSize = MaxRecordLength - InlineSiteSize - AnnotationSize; |
| if (Buffer.size() >= MaxBufferSize) |
| break; |
| |
| if (Loc.getFunctionId() == Frag.SiteFuncId) { |
| CurSourceLoc.File = Loc.getFileNum(); |
| CurSourceLoc.Line = Loc.getLine(); |
| } else { |
| auto I = SiteInfo->InlinedAtMap.find(Loc.getFunctionId()); |
| if (I != SiteInfo->InlinedAtMap.end()) { |
| // This .cv_loc is from a child inline call site. Use the source |
| // location of the inlined call site instead of the .cv_loc directive |
| // source location. |
| CurSourceLoc = I->second; |
| } else { |
| // We've hit a cv_loc not attributed to this inline call site. Use this |
| // label to end the PC range. |
| if (HaveOpenRange) { |
| unsigned Length = computeLabelDiff(Layout, LastLabel, Loc.getLabel()); |
| compressAnnotation(BinaryAnnotationsOpCode::ChangeCodeLength, Buffer); |
| compressAnnotation(Length, Buffer); |
| LastLabel = Loc.getLabel(); |
| } |
| HaveOpenRange = false; |
| continue; |
| } |
| } |
| |
| // Skip this .cv_loc if we have an open range and this isn't a meaningful |
| // source location update. The current table format does not support column |
| // info, so we can skip updates for those. |
| if (HaveOpenRange && CurSourceLoc.File == LastSourceLoc.File && |
| CurSourceLoc.Line == LastSourceLoc.Line) |
| continue; |
| |
| HaveOpenRange = true; |
| |
| if (CurSourceLoc.File != LastSourceLoc.File) { |
| unsigned FileOffset = static_cast<const MCConstantExpr *>( |
| Files[CurSourceLoc.File - 1] |
| .ChecksumTableOffset->getVariableValue()) |
| ->getValue(); |
| compressAnnotation(BinaryAnnotationsOpCode::ChangeFile, Buffer); |
| compressAnnotation(FileOffset, Buffer); |
| } |
| |
| int LineDelta = CurSourceLoc.Line - LastSourceLoc.Line; |
| unsigned EncodedLineDelta = encodeSignedNumber(LineDelta); |
| unsigned CodeDelta = computeLabelDiff(Layout, LastLabel, Loc.getLabel()); |
| if (CodeDelta == 0 && LineDelta != 0) { |
| compressAnnotation(BinaryAnnotationsOpCode::ChangeLineOffset, Buffer); |
| compressAnnotation(EncodedLineDelta, Buffer); |
| } else if (EncodedLineDelta < 0x8 && CodeDelta <= 0xf) { |
| // The ChangeCodeOffsetAndLineOffset combination opcode is used when the |
| // encoded line delta uses 3 or fewer set bits and the code offset fits |
| // in one nibble. |
| unsigned Operand = (EncodedLineDelta << 4) | CodeDelta; |
| compressAnnotation(BinaryAnnotationsOpCode::ChangeCodeOffsetAndLineOffset, |
| Buffer); |
| compressAnnotation(Operand, Buffer); |
| } else { |
| // Otherwise use the separate line and code deltas. |
| if (LineDelta != 0) { |
| compressAnnotation(BinaryAnnotationsOpCode::ChangeLineOffset, Buffer); |
| compressAnnotation(EncodedLineDelta, Buffer); |
| } |
| compressAnnotation(BinaryAnnotationsOpCode::ChangeCodeOffset, Buffer); |
| compressAnnotation(CodeDelta, Buffer); |
| } |
| |
| LastLabel = Loc.getLabel(); |
| LastSourceLoc = CurSourceLoc; |
| } |
| |
| assert(HaveOpenRange); |
| |
| unsigned EndSymLength = |
| computeLabelDiff(Layout, LastLabel, Frag.getFnEndSym()); |
| unsigned LocAfterLength = ~0U; |
| ArrayRef<MCCVLoc> LocAfter = getLinesForExtent(LocEnd, LocEnd + 1); |
| if (!LocAfter.empty()) { |
| // Only try to compute this difference if we're in the same section. |
| const MCCVLoc &Loc = LocAfter[0]; |
| if (&Loc.getLabel()->getSection() == &LastLabel->getSection()) |
| LocAfterLength = computeLabelDiff(Layout, LastLabel, Loc.getLabel()); |
| } |
| |
| compressAnnotation(BinaryAnnotationsOpCode::ChangeCodeLength, Buffer); |
| compressAnnotation(std::min(EndSymLength, LocAfterLength), Buffer); |
| } |
| |
| void CodeViewContext::encodeDefRange(MCAsmLayout &Layout, |
| MCCVDefRangeFragment &Frag) { |
| MCContext &Ctx = Layout.getAssembler().getContext(); |
| SmallVectorImpl<char> &Contents = Frag.getContents(); |
| Contents.clear(); |
| SmallVectorImpl<MCFixup> &Fixups = Frag.getFixups(); |
| Fixups.clear(); |
| raw_svector_ostream OS(Contents); |
| |
| // Compute all the sizes up front. |
| SmallVector<std::pair<unsigned, unsigned>, 4> GapAndRangeSizes; |
| const MCSymbol *LastLabel = nullptr; |
| for (std::pair<const MCSymbol *, const MCSymbol *> Range : Frag.getRanges()) { |
| unsigned GapSize = |
| LastLabel ? computeLabelDiff(Layout, LastLabel, Range.first) : 0; |
| unsigned RangeSize = computeLabelDiff(Layout, Range.first, Range.second); |
| GapAndRangeSizes.push_back({GapSize, RangeSize}); |
| LastLabel = Range.second; |
| } |
| |
| // Write down each range where the variable is defined. |
| for (size_t I = 0, E = Frag.getRanges().size(); I != E;) { |
| // If the range size of multiple consecutive ranges is under the max, |
| // combine the ranges and emit some gaps. |
| const MCSymbol *RangeBegin = Frag.getRanges()[I].first; |
| unsigned RangeSize = GapAndRangeSizes[I].second; |
| size_t J = I + 1; |
| for (; J != E; ++J) { |
| unsigned GapAndRangeSize = GapAndRangeSizes[J].first + GapAndRangeSizes[J].second; |
| if (RangeSize + GapAndRangeSize > MaxDefRange) |
| break; |
| RangeSize += GapAndRangeSize; |
| } |
| unsigned NumGaps = J - I - 1; |
| |
| support::endian::Writer LEWriter(OS, support::little); |
| |
| unsigned Bias = 0; |
| // We must split the range into chunks of MaxDefRange, this is a fundamental |
| // limitation of the file format. |
| do { |
| uint16_t Chunk = std::min((uint32_t)MaxDefRange, RangeSize); |
| |
| const MCSymbolRefExpr *SRE = MCSymbolRefExpr::create(RangeBegin, Ctx); |
| const MCBinaryExpr *BE = |
| MCBinaryExpr::createAdd(SRE, MCConstantExpr::create(Bias, Ctx), Ctx); |
| MCValue Res; |
| BE->evaluateAsRelocatable(Res, &Layout, /*Fixup=*/nullptr); |
| |
| // Each record begins with a 2-byte number indicating how large the record |
| // is. |
| StringRef FixedSizePortion = Frag.getFixedSizePortion(); |
| // Our record is a fixed sized prefix and a LocalVariableAddrRange that we |
| // are artificially constructing. |
| size_t RecordSize = FixedSizePortion.size() + |
| sizeof(LocalVariableAddrRange) + 4 * NumGaps; |
| // Write out the record size. |
| LEWriter.write<uint16_t>(RecordSize); |
| // Write out the fixed size prefix. |
| OS << FixedSizePortion; |
| // Make space for a fixup that will eventually have a section relative |
| // relocation pointing at the offset where the variable becomes live. |
| Fixups.push_back(MCFixup::create(Contents.size(), BE, FK_SecRel_4)); |
| LEWriter.write<uint32_t>(0); // Fixup for code start. |
| // Make space for a fixup that will record the section index for the code. |
| Fixups.push_back(MCFixup::create(Contents.size(), BE, FK_SecRel_2)); |
| LEWriter.write<uint16_t>(0); // Fixup for section index. |
| // Write down the range's extent. |
| LEWriter.write<uint16_t>(Chunk); |
| |
| // Move on to the next range. |
| Bias += Chunk; |
| RangeSize -= Chunk; |
| } while (RangeSize > 0); |
| |
| // Emit the gaps afterwards. |
| assert((NumGaps == 0 || Bias <= MaxDefRange) && |
| "large ranges should not have gaps"); |
| unsigned GapStartOffset = GapAndRangeSizes[I].second; |
| for (++I; I != J; ++I) { |
| unsigned GapSize, RangeSize; |
| assert(I < GapAndRangeSizes.size()); |
| std::tie(GapSize, RangeSize) = GapAndRangeSizes[I]; |
| LEWriter.write<uint16_t>(GapStartOffset); |
| LEWriter.write<uint16_t>(GapSize); |
| GapStartOffset += GapSize + RangeSize; |
| } |
| } |
| } |