Import prebuilt clang toolchain for linux.
diff --git a/linux-x64/clang/include/llvm/MC/MCSectionELF.h b/linux-x64/clang/include/llvm/MC/MCSectionELF.h
new file mode 100644
index 0000000..00c289c
--- /dev/null
+++ b/linux-x64/clang/include/llvm/MC/MCSectionELF.h
@@ -0,0 +1,99 @@
+//===- MCSectionELF.h - ELF Machine Code Sections ---------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the MCSectionELF class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MC_MCSECTIONELF_H
+#define LLVM_MC_MCSECTIONELF_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/MC/MCSection.h"
+#include "llvm/MC/MCSymbolELF.h"
+#include "llvm/MC/SectionKind.h"
+
+namespace llvm {
+
+class MCSymbol;
+
+/// This represents a section on linux, lots of unix variants and some bare
+/// metal systems.
+class MCSectionELF final : public MCSection {
+  /// This is the name of the section.  The referenced memory is owned by
+  /// TargetLoweringObjectFileELF's ELFUniqueMap.
+  StringRef SectionName;
+
+  /// This is the sh_type field of a section, drawn from the enums below.
+  unsigned Type;
+
+  /// This is the sh_flags field of a section, drawn from the enums below.
+  unsigned Flags;
+
+  unsigned UniqueID;
+
+  /// The size of each entry in this section. This size only makes sense for
+  /// sections that contain fixed-sized entries. If a section does not contain
+  /// fixed-sized entries 'EntrySize' will be 0.
+  unsigned EntrySize;
+
+  const MCSymbolELF *Group;
+
+  /// sh_info for SHF_LINK_ORDER (can be null).
+  const MCSymbol *AssociatedSymbol;
+
+private:
+  friend class MCContext;
+
+  MCSectionELF(StringRef Section, unsigned type, unsigned flags, SectionKind K,
+               unsigned entrySize, const MCSymbolELF *group, unsigned UniqueID,
+               MCSymbol *Begin, const MCSymbolELF *AssociatedSymbol)
+      : MCSection(SV_ELF, K, Begin), SectionName(Section), Type(type),
+        Flags(flags), UniqueID(UniqueID), EntrySize(entrySize), Group(group),
+        AssociatedSymbol(AssociatedSymbol) {
+    if (Group)
+      Group->setIsSignature();
+  }
+
+  void setSectionName(StringRef Name) { SectionName = Name; }
+
+public:
+  ~MCSectionELF();
+
+  /// Decides whether a '.section' directive should be printed before the
+  /// section name
+  bool ShouldOmitSectionDirective(StringRef Name, const MCAsmInfo &MAI) const;
+
+  StringRef getSectionName() const { return SectionName; }
+  unsigned getType() const { return Type; }
+  unsigned getFlags() const { return Flags; }
+  unsigned getEntrySize() const { return EntrySize; }
+  void setFlags(unsigned F) { Flags = F; }
+  const MCSymbolELF *getGroup() const { return Group; }
+
+  void PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
+                            raw_ostream &OS,
+                            const MCExpr *Subsection) const override;
+  bool UseCodeAlign() const override;
+  bool isVirtualSection() const override;
+
+  bool isUnique() const { return UniqueID != ~0U; }
+  unsigned getUniqueID() const { return UniqueID; }
+
+  const MCSection *getAssociatedSection() const { return &AssociatedSymbol->getSection(); }
+  const MCSymbol *getAssociatedSymbol() const { return AssociatedSymbol; }
+
+  static bool classof(const MCSection *S) {
+    return S->getVariant() == SV_ELF;
+  }
+};
+
+} // end namespace llvm
+
+#endif // LLVM_MC_MCSECTIONELF_H