[Assembler] Allow non-fatal errors after parsing
[oota-llvm.git] / lib / MC / MCContext.cpp
index 9d8a57e55f6cda00c1d423d80a5afa597333b798..383540a7a8fa3714ccfc45ca34c3cc1d85f5b372 100644 (file)
@@ -10,6 +10,7 @@
 #include "llvm/MC/MCContext.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCDwarf.h"
 #include "llvm/MC/MCLabel.h"
 #include "llvm/MC/MCSectionCOFF.h"
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCSectionMachO.h"
-#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSymbolCOFF.h"
+#include "llvm/MC/MCSymbolELF.h"
+#include "llvm/MC/MCSymbolMachO.h"
+#include "llvm/Support/COFF.h"
 #include "llvm/Support/ELF.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
@@ -33,11 +38,11 @@ MCContext::MCContext(const MCAsmInfo *mai, const MCRegisterInfo *mri,
                      const MCObjectFileInfo *mofi, const SourceMgr *mgr,
                      bool DoAutoReset)
     : SrcMgr(mgr), MAI(mai), MRI(mri), MOFI(mofi), Allocator(),
-      Symbols(Allocator), UsedNames(Allocator), NextUniqueID(0),
+      Symbols(Allocator), UsedNames(Allocator),
       CurrentDwarfLoc(0, 0, 0, DWARF2_FLAG_IS_STMT, 0, 0), DwarfLocSeen(false),
       GenDwarfForAssembly(false), GenDwarfFileNumber(0), DwarfVersion(4),
       AllowTemporaryLabels(true), DwarfCompileUnitID(0),
-      AutoReset(DoAutoReset) {
+      AutoReset(DoAutoReset), HadError(false) {
 
   std::error_code EC = llvm::sys::fs::current_path(CompilationDir);
   if (EC)
@@ -53,7 +58,6 @@ MCContext::MCContext(const MCAsmInfo *mai, const MCRegisterInfo *mri,
 }
 
 MCContext::~MCContext() {
-
   if (AutoReset)
     reset();
 
@@ -61,7 +65,7 @@ MCContext::~MCContext() {
   // we don't need to free them here.
 
   // If the stream for the .secure_log_unique directive was created free it.
-  delete (raw_ostream*)SecureLog;
+  delete (raw_ostream *)SecureLog;
 }
 
 //===----------------------------------------------------------------------===//
@@ -69,92 +73,156 @@ MCContext::~MCContext() {
 //===----------------------------------------------------------------------===//
 
 void MCContext::reset() {
+  // Call the destructors so the fragments are freed
+  COFFAllocator.DestroyAll();
+  ELFAllocator.DestroyAll();
+  MachOAllocator.DestroyAll();
+
+  MCSubtargetAllocator.DestroyAll();
   UsedNames.clear();
   Symbols.clear();
+  SectionSymbols.clear();
   Allocator.Reset();
   Instances.clear();
   CompilationDir.clear();
   MainFileName.clear();
   MCDwarfLineTablesCUMap.clear();
-  SectionStartEndSyms.clear();
+  SectionsForRanges.clear();
   MCGenDwarfLabelEntries.clear();
   DwarfDebugFlags = StringRef();
   DwarfCompileUnitID = 0;
-  CurrentDwarfLoc = MCDwarfLoc(0,0,0,DWARF2_FLAG_IS_STMT,0,0);
+  CurrentDwarfLoc = MCDwarfLoc(0, 0, 0, DWARF2_FLAG_IS_STMT, 0, 0);
 
   MachOUniquingMap.clear();
   ELFUniquingMap.clear();
   COFFUniquingMap.clear();
 
-  NextUniqueID = 0;
+  NextID.clear();
   AllowTemporaryLabels = true;
   DwarfLocSeen = false;
   GenDwarfForAssembly = false;
   GenDwarfFileNumber = 0;
+
+  HadError = false;
 }
 
 //===----------------------------------------------------------------------===//
 // Symbol Manipulation
 //===----------------------------------------------------------------------===//
 
-MCSymbol *MCContext::GetOrCreateSymbol(StringRef Name) {
-  assert(!Name.empty() && "Normal symbols cannot be unnamed!");
+MCSymbol *MCContext::getOrCreateSymbol(const Twine &Name) {
+  SmallString<128> NameSV;
+  StringRef NameRef = Name.toStringRef(NameSV);
+
+  assert(!NameRef.empty() && "Normal symbols cannot be unnamed!");
 
-  // Do the lookup and get the entire StringMapEntry.  We want access to the
-  // key if we are creating the entry.
-  StringMapEntry<MCSymbol*> &Entry = Symbols.GetOrCreateValue(Name);
-  MCSymbol *Sym = Entry.getValue();
+  MCSymbol *&Sym = Symbols[NameRef];
+  if (!Sym)
+    Sym = createSymbol(NameRef, false, false);
 
+  return Sym;
+}
+
+MCSymbolELF *MCContext::getOrCreateSectionSymbol(const MCSectionELF &Section) {
+  MCSymbolELF *&Sym = SectionSymbols[&Section];
   if (Sym)
     return Sym;
 
-  Sym = CreateSymbol(Name);
-  Entry.setValue(Sym);
+  StringRef Name = Section.getSectionName();
+
+  MCSymbol *&OldSym = Symbols[Name];
+  if (OldSym && OldSym->isUndefined()) {
+    Sym = cast<MCSymbolELF>(OldSym);
+    return Sym;
+  }
+
+  auto NameIter = UsedNames.insert(std::make_pair(Name, true)).first;
+  Sym = new (&*NameIter, *this) MCSymbolELF(&*NameIter, /*isTemporary*/ false);
+
+  if (!OldSym)
+    OldSym = Sym;
+
   return Sym;
 }
 
-MCSymbol *MCContext::CreateSymbol(StringRef Name) {
-  // Determine whether this is an assembler temporary or normal label, if used.
-  bool isTemporary = false;
-  if (AllowTemporaryLabels)
-    isTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());
+MCSymbol *MCContext::getOrCreateFrameAllocSymbol(StringRef FuncName,
+                                                 unsigned Idx) {
+  return getOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + FuncName +
+                           "$frame_escape_" + Twine(Idx));
+}
+
+MCSymbol *MCContext::getOrCreateParentFrameOffsetSymbol(StringRef FuncName) {
+  return getOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + FuncName +
+                           "$parent_frame_offset");
+}
+
+MCSymbol *MCContext::getOrCreateLSDASymbol(StringRef FuncName) {
+  return getOrCreateSymbol(Twine(MAI->getPrivateGlobalPrefix()) + "__ehtable$" +
+                           FuncName);
+}
 
-  StringMapEntry<bool> *NameEntry = &UsedNames.GetOrCreateValue(Name);
-  if (NameEntry->getValue()) {
-    assert(isTemporary && "Cannot rename non-temporary symbols");
-    SmallString<128> NewName = Name;
-    do {
+MCSymbol *MCContext::createSymbolImpl(const StringMapEntry<bool> *Name,
+                                      bool IsTemporary) {
+  if (MOFI) {
+    switch (MOFI->getObjectFileType()) {
+    case MCObjectFileInfo::IsCOFF:
+      return new (Name, *this) MCSymbolCOFF(Name, IsTemporary);
+    case MCObjectFileInfo::IsELF:
+      return new (Name, *this) MCSymbolELF(Name, IsTemporary);
+    case MCObjectFileInfo::IsMachO:
+      return new (Name, *this) MCSymbolMachO(Name, IsTemporary);
+    }
+  }
+  return new (Name, *this) MCSymbol(MCSymbol::SymbolKindUnset, Name,
+                                    IsTemporary);
+}
+
+MCSymbol *MCContext::createSymbol(StringRef Name, bool AlwaysAddSuffix,
+                                  bool CanBeUnnamed) {
+  if (CanBeUnnamed && !UseNamesOnTempLabels)
+    return createSymbolImpl(nullptr, true);
+
+  // Determine whether this is an user writter assembler temporary or normal
+  // label, if used.
+  bool IsTemporary = CanBeUnnamed;
+  if (AllowTemporaryLabels && !IsTemporary)
+    IsTemporary = Name.startswith(MAI->getPrivateGlobalPrefix());
+
+  SmallString<128> NewName = Name;
+  bool AddSuffix = AlwaysAddSuffix;
+  unsigned &NextUniqueID = NextID[Name];
+  for (;;) {
+    if (AddSuffix) {
       NewName.resize(Name.size());
       raw_svector_ostream(NewName) << NextUniqueID++;
-      NameEntry = &UsedNames.GetOrCreateValue(NewName);
-    } while (NameEntry->getValue());
+    }
+    auto NameEntry = UsedNames.insert(std::make_pair(NewName, true));
+    if (NameEntry.second) {
+      // Ok, we found a name. Have the MCSymbol object itself refer to the copy
+      // of the string that is embedded in the UsedNames entry.
+      return createSymbolImpl(&*NameEntry.first, IsTemporary);
+    }
+    assert(IsTemporary && "Cannot rename non-temporary symbols");
+    AddSuffix = true;
   }
-  NameEntry->setValue(true);
-
-  // Ok, the entry doesn't already exist.  Have the MCSymbol object itself refer
-  // to the copy of the string that is embedded in the UsedNames entry.
-  MCSymbol *Result = new (*this) MCSymbol(NameEntry->getKey(), isTemporary);
-
-  return Result;
+  llvm_unreachable("Infinite loop");
 }
 
-MCSymbol *MCContext::GetOrCreateSymbol(const Twine &Name) {
+MCSymbol *MCContext::createTempSymbol(const Twine &Name, bool AlwaysAddSuffix,
+                                      bool CanBeUnnamed) {
   SmallString<128> NameSV;
-  return GetOrCreateSymbol(Name.toStringRef(NameSV));
+  raw_svector_ostream(NameSV) << MAI->getPrivateGlobalPrefix() << Name;
+  return createSymbol(NameSV, AlwaysAddSuffix, CanBeUnnamed);
 }
 
-MCSymbol *MCContext::CreateLinkerPrivateTempSymbol() {
+MCSymbol *MCContext::createLinkerPrivateTempSymbol() {
   SmallString<128> NameSV;
-  raw_svector_ostream(NameSV)
-    << MAI->getLinkerPrivateGlobalPrefix() << "tmp" << NextUniqueID++;
-  return CreateSymbol(NameSV);
+  raw_svector_ostream(NameSV) << MAI->getLinkerPrivateGlobalPrefix() << "tmp";
+  return createSymbol(NameSV, true, false);
 }
 
-MCSymbol *MCContext::CreateTempSymbol() {
-  SmallString<128> NameSV;
-  raw_svector_ostream(NameSV)
-    << MAI->getPrivateGlobalPrefix() << "tmp" << NextUniqueID++;
-  return CreateSymbol(NameSV);
+MCSymbol *MCContext::createTempSymbol(bool CanBeUnnamed) {
+  return createTempSymbol("tmp", true, CanBeUnnamed);
 }
 
 unsigned MCContext::NextInstance(unsigned LocalLabelVal) {
@@ -175,16 +243,16 @@ MCSymbol *MCContext::getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
                                                        unsigned Instance) {
   MCSymbol *&Sym = LocalSymbols[std::make_pair(LocalLabelVal, Instance)];
   if (!Sym)
-    Sym = CreateTempSymbol();
+    Sym = createTempSymbol(false);
   return Sym;
 }
 
-MCSymbol *MCContext::CreateDirectionalLocalSymbol(unsigned LocalLabelVal) {
+MCSymbol *MCContext::createDirectionalLocalSymbol(unsigned LocalLabelVal) {
   unsigned Instance = NextInstance(LocalLabelVal);
   return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
 }
 
-MCSymbol *MCContext::GetDirectionalLocalSymbol(unsigned LocalLabelVal,
+MCSymbol *MCContext::getDirectionalLocalSymbol(unsigned LocalLabelVal,
                                                bool Before) {
   unsigned Instance = GetInstance(LocalLabelVal);
   if (!Before)
@@ -192,24 +260,20 @@ MCSymbol *MCContext::GetDirectionalLocalSymbol(unsigned LocalLabelVal,
   return getOrCreateDirectionalLocalSymbol(LocalLabelVal, Instance);
 }
 
-MCSymbol *MCContext::LookupSymbol(StringRef Name) const {
-  return Symbols.lookup(Name);
-}
-
-MCSymbol *MCContext::LookupSymbol(const Twine &Name) const {
+MCSymbol *MCContext::lookupSymbol(const Twine &Name) const {
   SmallString<128> NameSV;
-  Name.toVector(NameSV);
-  return LookupSymbol(NameSV.str());
+  StringRef NameRef = Name.toStringRef(NameSV);
+  return Symbols.lookup(NameRef);
 }
 
 //===----------------------------------------------------------------------===//
 // Section Management
 //===----------------------------------------------------------------------===//
 
-const MCSectionMachO *MCContext::
-getMachOSection(StringRef Segment, StringRef Section,
-                unsigned TypeAndAttributes,
-                unsigned Reserved2, SectionKind Kind) {
+MCSectionMachO *MCContext::getMachOSection(StringRef Segment, StringRef Section,
+                                           unsigned TypeAndAttributes,
+                                           unsigned Reserved2, SectionKind Kind,
+                                           const char *BeginSymName) {
 
   // We unique sections by their segment/section pair.  The returned section
   // may not have the same flags as the requested section, if so this should be
@@ -222,107 +286,149 @@ getMachOSection(StringRef Segment, StringRef Section,
   Name += Section;
 
   // Do the lookup, if we have a hit, return it.
-  const MCSectionMachO *&Entry = MachOUniquingMap[Name.str()];
-  if (Entry) return Entry;
+  MCSectionMachO *&Entry = MachOUniquingMap[Name];
+  if (Entry)
+    return Entry;
 
-  // Otherwise, return a new section.
-  return Entry = new (*this) MCSectionMachO(Segment, Section, TypeAndAttributes,
-                                            Reserved2, Kind);
-}
+  MCSymbol *Begin = nullptr;
+  if (BeginSymName)
+    Begin = createTempSymbol(BeginSymName, false);
 
-const MCSectionELF *MCContext::
-getELFSection(StringRef Section, unsigned Type, unsigned Flags,
-              SectionKind Kind) {
-  return getELFSection(Section, Type, Flags, Kind, 0, "");
+  // Otherwise, return a new section.
+  return Entry = new (MachOAllocator.Allocate()) MCSectionMachO(
+             Segment, Section, TypeAndAttributes, Reserved2, Kind, Begin);
 }
 
-void MCContext::renameELFSection(const MCSectionELF *Section, StringRef Name) {
+void MCContext::renameELFSection(MCSectionELF *Section, StringRef Name) {
   StringRef GroupName;
   if (const MCSymbol *Group = Section->getGroup())
     GroupName = Group->getName();
 
-  ELFUniquingMap.erase(SectionGroupPair(Section->getSectionName(), GroupName));
-  auto I =
-      ELFUniquingMap.insert(std::make_pair(SectionGroupPair(Name, GroupName),
-                                           Section)).first;
-  StringRef CachedName = I->first.first;
-  const_cast<MCSectionELF*>(Section)->setSectionName(CachedName);
+  unsigned UniqueID = Section->getUniqueID();
+  ELFUniquingMap.erase(
+      ELFSectionKey{Section->getSectionName(), GroupName, UniqueID});
+  auto I = ELFUniquingMap.insert(std::make_pair(
+                                     ELFSectionKey{Name, GroupName, UniqueID},
+                                     Section))
+               .first;
+  StringRef CachedName = I->first.SectionName;
+  const_cast<MCSectionELF *>(Section)->setSectionName(CachedName);
+}
+
+MCSectionELF *MCContext::createELFRelSection(StringRef Name, unsigned Type,
+                                             unsigned Flags, unsigned EntrySize,
+                                             const MCSymbolELF *Group,
+                                             const MCSectionELF *Associated) {
+  StringMap<bool>::iterator I;
+  bool Inserted;
+  std::tie(I, Inserted) = ELFRelSecNames.insert(std::make_pair(Name, true));
+
+  return new (ELFAllocator.Allocate())
+      MCSectionELF(I->getKey(), Type, Flags, SectionKind::getReadOnly(),
+                   EntrySize, Group, true, nullptr, Associated);
 }
 
-const MCSectionELF *MCContext::
-getELFSection(StringRef Section, unsigned Type, unsigned Flags,
-              SectionKind Kind, unsigned EntrySize, StringRef Group) {
+MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
+                                       unsigned Flags, unsigned EntrySize,
+                                       StringRef Group, unsigned UniqueID,
+                                       const char *BeginSymName) {
+  MCSymbolELF *GroupSym = nullptr;
+  if (!Group.empty())
+    GroupSym = cast<MCSymbolELF>(getOrCreateSymbol(Group));
+
+  return getELFSection(Section, Type, Flags, EntrySize, GroupSym, UniqueID,
+                       BeginSymName, nullptr);
+}
+
+MCSectionELF *MCContext::getELFSection(StringRef Section, unsigned Type,
+                                       unsigned Flags, unsigned EntrySize,
+                                       const MCSymbolELF *GroupSym,
+                                       unsigned UniqueID,
+                                       const char *BeginSymName,
+                                       const MCSectionELF *Associated) {
+  StringRef Group = "";
+  if (GroupSym)
+    Group = GroupSym->getName();
   // Do the lookup, if we have a hit, return it.
   auto IterBool = ELFUniquingMap.insert(
-      std::make_pair(SectionGroupPair(Section, Group), nullptr));
+      std::make_pair(ELFSectionKey{Section, Group, UniqueID}, nullptr));
   auto &Entry = *IterBool.first;
-  if (!IterBool.second) return Entry.second;
+  if (!IterBool.second)
+    return Entry.second;
 
-  // Possibly refine the entry size first.
-  if (!EntrySize) {
-    EntrySize = MCSectionELF::DetermineEntrySize(Kind);
-  }
+  StringRef CachedName = Entry.first.SectionName;
 
-  MCSymbol *GroupSym = nullptr;
-  if (!Group.empty())
-    GroupSym = GetOrCreateSymbol(Group);
+  SectionKind Kind;
+  if (Flags & ELF::SHF_EXECINSTR)
+    Kind = SectionKind::getText();
+  else
+    Kind = SectionKind::getReadOnly();
+
+  MCSymbol *Begin = nullptr;
+  if (BeginSymName)
+    Begin = createTempSymbol(BeginSymName, false);
 
-  StringRef CachedName = Entry.first.first;
-  MCSectionELF *Result = new (*this)
-      MCSectionELF(CachedName, Type, Flags, Kind, EntrySize, GroupSym);
+  MCSectionELF *Result = new (ELFAllocator.Allocate())
+      MCSectionELF(CachedName, Type, Flags, Kind, EntrySize, GroupSym, UniqueID,
+                   Begin, Associated);
   Entry.second = Result;
   return Result;
 }
 
-const MCSectionELF *MCContext::CreateELFGroupSection() {
-  MCSectionELF *Result =
-    new (*this) MCSectionELF(".group", ELF::SHT_GROUP, 0,
-                             SectionKind::getReadOnly(), 4, nullptr);
+MCSectionELF *MCContext::createELFGroupSection(const MCSymbolELF *Group) {
+  MCSectionELF *Result = new (ELFAllocator.Allocate())
+      MCSectionELF(".group", ELF::SHT_GROUP, 0, SectionKind::getReadOnly(), 4,
+                   Group, ~0, nullptr, nullptr);
   return Result;
 }
 
-const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
-                                               unsigned Characteristics,
-                                               SectionKind Kind,
-                                               StringRef COMDATSymName,
-                                               int Selection) {
-  // Do the lookup, if we have a hit, return it.
+MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
+                                         unsigned Characteristics,
+                                         SectionKind Kind,
+                                         StringRef COMDATSymName, int Selection,
+                                         const char *BeginSymName) {
+  MCSymbol *COMDATSymbol = nullptr;
+  if (!COMDATSymName.empty()) {
+    COMDATSymbol = getOrCreateSymbol(COMDATSymName);
+    COMDATSymName = COMDATSymbol->getName();
+  }
 
-  SectionGroupTriple T(Section, COMDATSymName, Selection);
+  // Do the lookup, if we have a hit, return it.
+  COFFSectionKey T{Section, COMDATSymName, Selection};
   auto IterBool = COFFUniquingMap.insert(std::make_pair(T, nullptr));
   auto Iter = IterBool.first;
   if (!IterBool.second)
     return Iter->second;
 
-  MCSymbol *COMDATSymbol = nullptr;
-  if (!COMDATSymName.empty())
-    COMDATSymbol = GetOrCreateSymbol(COMDATSymName);
+  MCSymbol *Begin = nullptr;
+  if (BeginSymName)
+    Begin = createTempSymbol(BeginSymName, false);
 
-  StringRef CachedName = std::get<0>(Iter->first);
-  MCSectionCOFF *Result = new (*this)
-      MCSectionCOFF(CachedName, Characteristics, COMDATSymbol, Selection, Kind);
+  StringRef CachedName = Iter->first.SectionName;
+  MCSectionCOFF *Result = new (COFFAllocator.Allocate()) MCSectionCOFF(
+      CachedName, Characteristics, COMDATSymbol, Selection, Kind, Begin);
 
   Iter->second = Result;
   return Result;
 }
 
-const MCSectionCOFF *
-MCContext::getCOFFSection(StringRef Section, unsigned Characteristics,
-                          SectionKind Kind) {
-  return getCOFFSection(Section, Characteristics, Kind, "", 0);
+MCSectionCOFF *MCContext::getCOFFSection(StringRef Section,
+                                         unsigned Characteristics,
+                                         SectionKind Kind,
+                                         const char *BeginSymName) {
+  return getCOFFSection(Section, Characteristics, Kind, "", 0, BeginSymName);
 }
 
-const MCSectionCOFF *MCContext::getCOFFSection(StringRef Section) {
-  SectionGroupTriple T(Section, "", 0);
+MCSectionCOFF *MCContext::getCOFFSection(StringRef Section) {
+  COFFSectionKey T{Section, "", 0};
   auto Iter = COFFUniquingMap.find(T);
   if (Iter == COFFUniquingMap.end())
     return nullptr;
   return Iter->second;
 }
 
-const MCSectionCOFF *
-MCContext::getAssociativeCOFFSection(const MCSectionCOFF *Sec,
-                                     const MCSymbol *KeySym) {
+MCSectionCOFF *MCContext::getAssociativeCOFFSection(MCSectionCOFF *Sec,
+                                                    const MCSymbol *KeySym) {
   // Return the normal section if we don't have to be associative.
   if (!KeySym)
     return Sec;
@@ -336,15 +442,19 @@ MCContext::getAssociativeCOFFSection(const MCSectionCOFF *Sec,
                         COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE);
 }
 
+MCSubtargetInfo &MCContext::getSubtargetCopy(const MCSubtargetInfo &STI) {
+  return *new (MCSubtargetAllocator.Allocate()) MCSubtargetInfo(STI);
+}
+
 //===----------------------------------------------------------------------===//
 // Dwarf Management
 //===----------------------------------------------------------------------===//
 
-/// GetDwarfFile - takes a file name an number to place in the dwarf file and
+/// getDwarfFile - takes a file name an number to place in the dwarf file and
 /// directory tables.  If the file number has already been allocated it is an
 /// error and zero is returned and the client reports the error, else the
 /// allocated file number is returned.  The file numbers may be in any order.
-unsigned MCContext::GetDwarfFile(StringRef Directory, StringRef FileName,
+unsigned MCContext::getDwarfFile(StringRef Directory, StringRef FileName,
                                  unsigned FileNumber, unsigned CUID) {
   MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
   return Table.getFile(Directory, FileName, FileNumber);
@@ -353,44 +463,38 @@ unsigned MCContext::GetDwarfFile(StringRef Directory, StringRef FileName,
 /// isValidDwarfFileNumber - takes a dwarf file number and returns true if it
 /// currently is assigned and false otherwise.
 bool MCContext::isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID) {
-  const SmallVectorImpl<MCDwarfFile>MCDwarfFiles = getMCDwarfFiles(CUID);
-  if(FileNumber == 0 || FileNumber >= MCDwarfFiles.size())
+  const SmallVectorImpl<MCDwarfFile> &MCDwarfFiles = getMCDwarfFiles(CUID);
+  if (FileNumber == 0 || FileNumber >= MCDwarfFiles.size())
     return false;
 
   return !MCDwarfFiles[FileNumber].Name.empty();
 }
 
-/// finalizeDwarfSections - Emit end symbols for each non-empty code section.
-/// Also remove empty sections from SectionStartEndSyms, to avoid generating
+/// Remove empty sections from SectionStartEndSyms, to avoid generating
 /// useless debug info for them.
 void MCContext::finalizeDwarfSections(MCStreamer &MCOS) {
-  MCContext &context = MCOS.getContext();
-
-  auto sec = SectionStartEndSyms.begin();
-  while (sec != SectionStartEndSyms.end()) {
-    assert(sec->second.first && "Start symbol must be set by now");
-    MCOS.SwitchSection(sec->first);
-    if (MCOS.mayHaveInstructions()) {
-      MCSymbol *SectionEndSym = context.CreateTempSymbol();
-      MCOS.EmitLabel(SectionEndSym);
-      sec->second.second = SectionEndSym;
-      ++sec;
-    } else {
-      MapVector<const MCSection *, std::pair<MCSymbol *, MCSymbol *> >::iterator
-        to_erase = sec;
-      sec = SectionStartEndSyms.erase(to_erase);
-    }
-  }
+  SectionsForRanges.remove_if(
+      [&](MCSection *Sec) { return !MCOS.mayHaveInstructions(*Sec); });
 }
 
-void MCContext::FatalError(SMLoc Loc, const Twine &Msg) const {
-  // If we have a source manager and a location, use it. Otherwise just
-  // use the generic report_fatal_error().
-  if (!SrcMgr || Loc == SMLoc())
+//===----------------------------------------------------------------------===//
+// Error Reporting
+//===----------------------------------------------------------------------===//
+
+void MCContext::reportError(SMLoc Loc, const Twine &Msg) {
+  HadError = true;
+
+  // If we have a source manager use it. Otherwise just use the generic
+  // report_fatal_error().
+  if (!SrcMgr)
     report_fatal_error(Msg, false);
 
   // Use the source manager to print the message.
   SrcMgr->PrintMessage(Loc, SourceMgr::DK_Error, Msg);
+}
+
+void MCContext::reportFatalError(SMLoc Loc, const Twine &Msg) {
+  reportError(Loc, Msg);
 
   // If we reached here, we are failing ungracefully. Run the interrupt handlers
   // to make sure any special cleanups get done, in particular that we remove