[DebugInfo] Support DWARF v5 source code embedding extension

In DWARF v5 the Line Number Program Header is extensible, allowing values with
new content types. In this extension a content type is added,
DW_LNCT_LLVM_source, which contains the embedded source code of the file.

Add new optional attribute for !DIFile IR metadata called source which contains
source text. Use this to output the source to the DWARF line table of code
objects. Analogously extend METADATA_FILE in Bitcode and .file directive in ASM
to support optional source.

Teach llvm-dwarfdump and llvm-objdump about the new values. Update the output
format of llvm-dwarfdump to make room for the new attribute on file_names
entries, and support embedded sources for the -source option in llvm-objdump.

Differential Revision: https://reviews.llvm.org/D42765

llvm-svn: 325970

docs/AMDGPUUsage.rst

@@ -780,7 +780,7 @@ The following relocation types are supported:
 DWARF
 -----
 
-Standard DWARF [DWARF]_ Version 2 sections can be generated. These contain
+Standard DWARF [DWARF]_ Version 5 sections can be generated. These contain
 information that maps the code object executable code and data to the source
 language constructs. It can be used by tools such as debuggers and profilers.
 
@@ -836,10 +836,60 @@ Register Mapping
 Source Text
 ~~~~~~~~~~~
 
-*This section is WIP.*
+Source text for online-compiled programs (e.g. those compiled by the OpenCL
+runtime) may be embedded into the DWARF v5 line table using the ``clang
+-gembed-source`` option, described in table :ref:`amdgpu-debug-options`.
 
-.. TODO
+For example:
-   DWARF extension to include runtime generated source text.
+
+``-gembed-source``
+  Enable the embedded source DWARF v5 extension.
+``-gno-embed-source``
+  Disable the embedded source DWARF v5 extension.
+
+  .. table:: AMDGPU Debug Options
+     :name: amdgpu-debug-options
+
+     ==================== ==================================================
+     Debug Flag           Description
+     ==================== ==================================================
+     -g[no-]embed-source  Enable/disable embedding source text in DWARF
+                          debug sections. Useful for environments where
+                          source cannot be written to disk, such as
+                          when performing online compilation.
+     ==================== ==================================================
+
+This option enables one extended content types in the DWARF v5 Line Number
+Program Header, which is used to encode embedded source.
+
+  .. table:: AMDGPU DWARF Line Number Program Header Extended Content Types
+     :name: amdgpu-dwarf-extended-content-types
+
+     ============================  ======================
+     Content Type                  Form
+     ============================  ======================
+     ``DW_LNCT_LLVM_source``       ``DW_FORM_line_strp``
+     ============================  ======================
+
+The source field will contain the UTF-8 encoded, null-terminated source text
+with ``'\n'`` line endings. When the source field is present, consumers can use
+the embedded source instead of attempting to discover the source on disk. When
+the source field is absent, consumers can access the file to get the source
+text.
+
+The above content type appears in the ``file_name_entry_format`` field of the
+line table prologue, and its corresponding value appear in the ``file_names``
+field. The current encoding of the content type is documented in table
+:ref:`amdgpu-dwarf-extended-content-types-encoding`
+
+  .. table:: AMDGPU DWARF Line Number Program Header Extended Content Types Encoding
+     :name: amdgpu-dwarf-extended-content-types-encoding
+
+     ============================  ====================
+     Content Type                  Value
+     ============================  ====================
+     ``DW_LNCT_LLVM_source``       0x2001
+     ============================  ====================
 
 .. _amdgpu-code-conventions:
 

include/llvm/BinaryFormat/Dwarf.def

@@ -747,6 +747,9 @@ HANDLE_DW_LNCT(0x02, directory_index)
 HANDLE_DW_LNCT(0x03, timestamp)
 HANDLE_DW_LNCT(0x04, size)
 HANDLE_DW_LNCT(0x05, MD5)
+// A vendor extension until http://dwarfstd.org/ShowIssue.php?issue=180201.1 is
+// accepted and incorporated into the next DWARF standard.
+HANDLE_DW_LNCT(0x2001, LLVM_source)
 
 // DWARF v5 Macro information.
 HANDLE_DW_MACRO(0x01, define)

include/llvm/DebugInfo/DIContext.h

@@ -31,6 +31,7 @@ namespace llvm {
 struct DILineInfo {
   std::string FileName;
   std::string FunctionName;
+  Optional<StringRef> Source;
   uint32_t Line = 0;
   uint32_t Column = 0;
   uint32_t StartLine = 0;

include/llvm/DebugInfo/DWARF/DWARFDebugLine.h

@@ -10,6 +10,7 @@
 #ifndef LLVM_DEBUGINFO_DWARFDEBUGLINE_H
 #define LLVM_DEBUGINFO_DWARFDEBUGLINE_H
 
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/DebugInfo/DIContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
@@ -36,6 +37,25 @@ public:
     uint64_t ModTime = 0;
     uint64_t Length = 0;
     MD5::MD5Result Checksum;
+    DWARFFormValue Source;
+  };
+
+  /// Tracks which optional content types are present in a DWARF file name
+  /// entry format.
+  struct ContentTypeTracker {
+    ContentTypeTracker() = default;
+
+    /// Whether filename entries provide a modification timestamp.
+    bool HasModTime = false;
+    /// Whether filename entries provide a file size.
+    bool HasLength = false;
+    /// For v5, whether filename entries provide an MD5 checksum.
+    bool HasMD5 = false;
+    /// For v5, whether filename entries provide source text.
+    bool HasSource = false;
+
+    /// Update tracked content types with \p ContentType.
+    void trackContentType(dwarf::LineNumberEntryFormat ContentType);
   };
 
   struct Prologue {
@@ -68,8 +88,8 @@ public:
     uint8_t LineRange;
     /// The number assigned to the first special opcode.
     uint8_t OpcodeBase;
-    /// For v5, whether filename entries provide an MD5 checksum.
+    /// This tracks which optional file format content types are present.
-    bool HasMD5;
+    ContentTypeTracker ContentTypes;
     std::vector<uint8_t> StandardOpcodeLengths;
     std::vector<DWARFFormValue> IncludeDirectories;
     std::vector<FileNameEntry> FileNames;
@@ -239,6 +259,8 @@ public:
   private:
     uint32_t findRowInSeq(const DWARFDebugLine::Sequence &Seq,
                           uint64_t Address) const;
+    Optional<StringRef> getSourceByIndex(uint64_t FileIndex,
+                                         DILineInfoSpecifier::FileLineInfoKind Kind) const;
   };
 
   const LineTable *getLineTable(uint32_t Offset) const;

include/llvm/IR/DIBuilder.h

@@ -18,7 +18,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/MapVector.h"
-#include "llvm/ADT/None.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
@@ -141,10 +141,13 @@ namespace llvm {
     /// Create a file descriptor to hold debugging information for a file.
     /// \param Filename  File name.
     /// \param Directory Directory.
-    /// \param Checksum  Checksum kind (e.g. CSK_MD5, CSK_SHA1, etc.) and value.
+    /// \param Checksum  Optional checksum kind (e.g. CSK_MD5, CSK_SHA1, etc.)
+    ///                  and value.
+    /// \param Source    Optional source text.
     DIFile *
     createFile(StringRef Filename, StringRef Directory,
-               Optional<DIFile::ChecksumInfo<StringRef>> Checksum = None);
+               Optional<DIFile::ChecksumInfo<StringRef>> Checksum = None,
+               Optional<StringRef> Source = None);
 
     /// Create debugging information entry for a macro.
     /// \param Parent     Macro parent (could be nullptr).

include/llvm/IR/DebugInfoMetadata.h

@@ -455,6 +455,7 @@ public:
 
   inline StringRef getFilename() const;
   inline StringRef getDirectory() const;
+  inline Optional<StringRef> getSource() const;
 
   StringRef getName() const;
   DIScopeRef getScope() const;
@@ -532,42 +533,48 @@ public:
 
 private:
   Optional<ChecksumInfo<MDString *>> Checksum;
+  Optional<MDString *> Source;
 
   DIFile(LLVMContext &C, StorageType Storage,
-         Optional<ChecksumInfo<MDString *>> CS,
+         Optional<ChecksumInfo<MDString *>> CS, Optional<MDString *> Src,
          ArrayRef<Metadata *> Ops)
       : DIScope(C, DIFileKind, Storage, dwarf::DW_TAG_file_type, Ops),
-        Checksum(CS) {}
+        Checksum(CS), Source(Src) {}
   ~DIFile() = default;
 
   static DIFile *getImpl(LLVMContext &Context, StringRef Filename,
                          StringRef Directory,
                          Optional<ChecksumInfo<StringRef>> CS,
+                         Optional<StringRef> Source,
                          StorageType Storage, bool ShouldCreate = true) {
     Optional<ChecksumInfo<MDString *>> MDChecksum;
     if (CS)
       MDChecksum.emplace(CS->Kind, getCanonicalMDString(Context, CS->Value));
     return getImpl(Context, getCanonicalMDString(Context, Filename),
                    getCanonicalMDString(Context, Directory), MDChecksum,
+                   Source ? Optional<MDString *>(getCanonicalMDString(Context, *Source)) : None,
                    Storage, ShouldCreate);
   }
   static DIFile *getImpl(LLVMContext &Context, MDString *Filename,
                          MDString *Directory,
                          Optional<ChecksumInfo<MDString *>> CS,
-                         StorageType Storage, bool ShouldCreate = true);
+                         Optional<MDString *> Source, StorageType Storage,
+                         bool ShouldCreate = true);
 
   TempDIFile cloneImpl() const {
     return getTemporary(getContext(), getFilename(), getDirectory(),
-                        getChecksum());
+                        getChecksum(), getSource());
   }
 
 public:
   DEFINE_MDNODE_GET(DIFile, (StringRef Filename, StringRef Directory,
-                             Optional<ChecksumInfo<StringRef>> CS = None),
+                             Optional<ChecksumInfo<StringRef>> CS = None,
-                    (Filename, Directory, CS))
+                             Optional<StringRef> Source = None),
+                    (Filename, Directory, CS, Source))
   DEFINE_MDNODE_GET(DIFile, (MDString * Filename, MDString *Directory,
-                             Optional<ChecksumInfo<MDString *>> CS = None),
+                             Optional<ChecksumInfo<MDString *>> CS = None,
-                    (Filename, Directory, CS))
+                             Optional<MDString *> Source = None),
+                    (Filename, Directory, CS, Source))
 
   TempDIFile clone() const { return cloneImpl(); }
 
@@ -579,10 +586,14 @@ public:
       StringRefChecksum.emplace(Checksum->Kind, Checksum->Value->getString());
     return StringRefChecksum;
   }
+  Optional<StringRef> getSource() const {
+    return Source ? Optional<StringRef>((*Source)->getString()) : None;
+  }
 
   MDString *getRawFilename() const { return getOperandAs<MDString>(0); }
   MDString *getRawDirectory() const { return getOperandAs<MDString>(1); }
   Optional<ChecksumInfo<MDString *>> getRawChecksum() const { return Checksum; }
+  Optional<MDString *> getRawSource() const { return Source; }
 
   static StringRef getChecksumKindAsString(ChecksumKind CSKind);
   static Optional<ChecksumKind> getChecksumKind(StringRef CSKindStr);
@@ -604,6 +615,12 @@ StringRef DIScope::getDirectory() const {
   return "";
 }
 
+Optional<StringRef> DIScope::getSource() const {
+  if (auto *F = getFile())
+    return F->getSource();
+  return None;
+}
+
 /// Base class for types.
 ///
 /// TODO: Remove the hardcoded name and context, since many types don't use
@@ -1408,6 +1425,7 @@ public:
   DIFile *getFile() const { return getScope()->getFile(); }
   StringRef getFilename() const { return getScope()->getFilename(); }
   StringRef getDirectory() const { return getScope()->getDirectory(); }
+  Optional<StringRef> getSource() const { return getScope()->getSource(); }
 
   /// Get the scope where this is inlined.
   ///
@@ -2177,6 +2195,12 @@ public:
     return "";
   }
 
+  Optional<StringRef> getSource() const {
+    if (auto *F = getFile())
+      return F->getSource();
+    return None;
+  }
+
   Metadata *getRawScope() const { return getOperand(0); }
   MDString *getRawName() const { return getOperandAs<MDString>(1); }
   Metadata *getRawFile() const { return getOperand(2); }
@@ -2624,6 +2648,12 @@ public:
     return "";
   }
 
+  Optional<StringRef> getSource() const {
+    if (auto *F = getFile())
+      return F->getSource();
+    return None;
+  }
+
   MDString *getRawName() const { return getOperandAs<MDString>(0); }
   Metadata *getRawFile() const { return getOperand(1); }
   MDString *getRawGetterName() const { return getOperandAs<MDString>(2); }

include/llvm/MC/MCContext.h

@@ -11,6 +11,7 @@
 #define LLVM_MC_MCCONTEXT_H
 
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
@@ -496,7 +497,8 @@ namespace llvm {
     /// Creates an entry in the dwarf file and directory tables.
     Expected<unsigned> getDwarfFile(StringRef Directory, StringRef FileName,
                                     unsigned FileNumber,
-                                    MD5::MD5Result *Checksum, unsigned CUID);
+                                    MD5::MD5Result *Checksum,
+                                    Optional<StringRef> Source, unsigned CUID);
 
     bool isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID = 0);
 

include/llvm/MC/MCDwarf.h

@@ -16,6 +16,7 @@
 #define LLVM_MC_MCDWARF_H
 
 #include "llvm/ADT/MapVector.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
@@ -48,7 +49,6 @@ class SourceMgr;
 /// index 0 is not used and not a valid dwarf file number).
 struct MCDwarfFile {
   // \brief The base name of the file without its directory path.
-  // The StringRef references memory allocated in the MCContext.
   std::string Name;
 
   // \brief The index into the list of directory names for this file name.
@@ -57,6 +57,10 @@ struct MCDwarfFile {
   /// The MD5 checksum, if there is one. Non-owning pointer to data allocated
   /// in MCContext.
   MD5::MD5Result *Checksum = nullptr;
+
+  /// The source code of the file. Non-owning reference to data allocated in
+  /// MCContext.
+  Optional<StringRef> Source;
 };
 
 /// \brief Instances of this class represent the information from a
@@ -211,11 +215,13 @@ struct MCDwarfLineTableHeader {
   StringMap<unsigned> SourceIdMap;
   StringRef CompilationDir;
   bool HasMD5 = false;
+  bool HasSource = false;
 
   MCDwarfLineTableHeader() = default;
 
   Expected<unsigned> tryGetFile(StringRef &Directory, StringRef &FileName,
                                 MD5::MD5Result *Checksum,
+                                Optional<StringRef> &Source,
                                 unsigned FileNumber = 0);
   std::pair<MCSymbol *, MCSymbol *>
   Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
@@ -240,8 +246,8 @@ public:
   }
 
   unsigned getFile(StringRef Directory, StringRef FileName,
-                   MD5::MD5Result *Checksum) {
+                   MD5::MD5Result *Checksum, Optional<StringRef> Source) {
-    return cantFail(Header.tryGetFile(Directory, FileName, Checksum));
+    return cantFail(Header.tryGetFile(Directory, FileName, Checksum, Source));
   }
 
   void Emit(MCStreamer &MCOS, MCDwarfLineTableParams Params) const;
@@ -261,10 +267,13 @@ public:
 
   Expected<unsigned> tryGetFile(StringRef &Directory, StringRef &FileName,
                                 MD5::MD5Result *Checksum,
+                                Optional<StringRef> Source,
                                 unsigned FileNumber = 0);
   unsigned getFile(StringRef &Directory, StringRef &FileName,
-                   MD5::MD5Result *Checksum, unsigned FileNumber = 0) {
+                   MD5::MD5Result *Checksum, Optional<StringRef> &Source,
-    return cantFail(tryGetFile(Directory, FileName, Checksum, FileNumber));
+                   unsigned FileNumber = 0) {
+    return cantFail(tryGetFile(Directory, FileName, Checksum, Source,
+                               FileNumber));
   }
 
   MCSymbol *getLabel() const {

include/llvm/MC/MCStreamer.h

@@ -16,6 +16,7 @@
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/MC/MCDirectives.h"
@@ -756,17 +757,22 @@ public:
   unsigned EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
                                   StringRef Filename,
                                   MD5::MD5Result *Checksum = nullptr,
+                                  Optional<StringRef> Source = None,
                                   unsigned CUID = 0) {
     return cantFail(
-        tryEmitDwarfFileDirective(FileNo, Directory, Filename, Checksum, CUID));
+        tryEmitDwarfFileDirective(FileNo, Directory, Filename, Checksum,
+                                  Source, CUID));
   }
 
-  /// Associate a filename with a specified logical file number.  Returns a
+  /// Associate a filename with a specified logical file number.
-  /// StringError for any problem, or the file number.  This implements the
+  /// Also associate a directory, optional checksum, and optional source
-  /// DWARF2 '.file 4 "foo.c"' assembler directive.
+  /// text with the logical file.  This implements the DWARF2
+  /// '.file 4 "dir/foo.c"' assembler directive, and the DWARF5
+  /// '.file 4 "dir/foo.c" md5 "..." source "..."' assembler directive.
   virtual Expected<unsigned> tryEmitDwarfFileDirective(
       unsigned FileNo, StringRef Directory, StringRef Filename,
-      MD5::MD5Result *Checksum = nullptr, unsigned CUID = 0);
+      MD5::MD5Result *Checksum = nullptr, Optional<StringRef> Source = None,
+      unsigned CUID = 0);
 
   /// \brief This implements the DWARF2 '.loc fileno lineno ...' assembler
   /// directive.

lib/AsmParser/LLParser.cpp

@@ -4243,9 +4243,10 @@ bool LLParser::ParseDISubroutineType(MDNode *&Result, bool IsDistinct) {
 }
 
 /// ParseDIFileType:
-///   ::= !DIFileType(filename: "path/to/file", directory: "/path/to/dir"
+///   ::= !DIFileType(filename: "path/to/file", directory: "/path/to/dir",
 ///                   checksumkind: CSK_MD5,
-///                   checksum: "000102030405060708090a0b0c0d0e0f")
+///                   checksum: "000102030405060708090a0b0c0d0e0f",
+///                   source: "source file contents")
 bool LLParser::ParseDIFile(MDNode *&Result, bool IsDistinct) {
   // The default constructed value for checksumkind is required, but will never
   // be used, as the parser checks if the field was actually Seen before using
@@ -4254,7 +4255,8 @@ bool LLParser::ParseDIFile(MDNode *&Result, bool IsDistinct) {
   REQUIRED(filename, MDStringField, );                                         \
   REQUIRED(directory, MDStringField, );                                        \
   OPTIONAL(checksumkind, ChecksumKindField, (DIFile::CSK_MD5));                \
-  OPTIONAL(checksum, MDStringField, );
+  OPTIONAL(checksum, MDStringField, );                                         \
+  OPTIONAL(source, MDStringField, );
   PARSE_MD_FIELDS();
 #undef VISIT_MD_FIELDS
 
@@ -4264,8 +4266,11 @@ bool LLParser::ParseDIFile(MDNode *&Result, bool IsDistinct) {
   else if (checksumkind.Seen || checksum.Seen)
     return Lex.Error("'checksumkind' and 'checksum' must be provided together");
 
+  Optional<MDString *> OptSource;
+  if (source.Seen)
+    OptSource = source.Val;
   Result = GET_OR_DISTINCT(DIFile, (Context, filename.Val, directory.Val,
-                                    OptChecksum));
+                                    OptChecksum, OptSource));
   return false;
 }
 

lib/Bitcode/Reader/MetadataLoader.cpp

@@ -1350,7 +1350,7 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
   }
 
   case bitc::METADATA_FILE: {
-    if (Record.size() != 3 && Record.size() != 5)
+    if (Record.size() != 3 && Record.size() != 5 && Record.size() != 6)
       return error("Invalid record");
 
     IsDistinct = Record[0];
@@ -1360,14 +1360,15 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
     // and the old encoding for CSK_None in the ChecksumKind. The new
     // representation reserves the value 0 in the ChecksumKind to continue to
     // encode None in a backwards-compatible way.
-    if (Record.size() == 5 && Record[3] && Record[4])
+    if (Record.size() > 4 && Record[3] && Record[4])
       Checksum.emplace(static_cast<DIFile::ChecksumKind>(Record[3]),
                        getMDString(Record[4]));
     MetadataList.assignValue(
         GET_OR_DISTINCT(
             DIFile,
-            (Context, getMDString(Record[1]), getMDString(Record[2]),
+            (Context, getMDString(Record[1]), getMDString(Record[2]), Checksum,
-             Checksum)),
+             Record.size() > 5 ? Optional<MDString *>(getMDString(Record[5]))
+                               : None)),
         NextMetadataNo);
     NextMetadataNo++;
     break;

lib/Bitcode/Writer/BitcodeWriter.cpp

@@ -1560,6 +1560,9 @@ void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
     Record.push_back(0);
     Record.push_back(VE.getMetadataOrNullID(nullptr));
   }
+  auto Source = N->getRawSource();
+  if (Source)
+    Record.push_back(VE.getMetadataOrNullID(*Source));
 
   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
   Record.clear();

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

@@ -102,9 +102,10 @@ unsigned DwarfCompileUnit::getOrCreateSourceID(const DIFile *File) {
   // extend .file to support this.
   unsigned CUID = Asm->OutStreamer->hasRawTextSupport() ? 0 : getUniqueID();
   if (!File)
-    return Asm->OutStreamer->EmitDwarfFileDirective(0, "", "", nullptr, CUID);
+    return Asm->OutStreamer->EmitDwarfFileDirective(0, "", "", nullptr, None, CUID);
   return Asm->OutStreamer->EmitDwarfFileDirective(
-      0, File->getDirectory(), File->getFilename(), getMD5AsBytes(File), CUID);
+      0, File->getDirectory(), File->getFilename(), getMD5AsBytes(File),
+      File->getSource(), CUID);
 }
 
 DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -1384,7 +1384,7 @@ void DwarfDebug::endFunctionImpl(const MachineFunction *MF) {
 void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
                                   unsigned Flags) {
   StringRef Fn;
-  unsigned Src = 1;
+  unsigned FileNo = 1;
   unsigned Discriminator = 0;
   if (auto *Scope = cast_or_null<DIScope>(S)) {
     Fn = Scope->getFilename();
@@ -1393,10 +1393,10 @@ void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S,
         Discriminator = LBF->getDiscriminator();
 
     unsigned CUID = Asm->OutStreamer->getContext().getDwarfCompileUnitID();
-    Src = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
+    FileNo = static_cast<DwarfCompileUnit &>(*InfoHolder.getUnits()[CUID])
               .getOrCreateSourceID(Scope->getFile());
   }
-  Asm->OutStreamer->EmitDwarfLocDirective(Src, Line, Col, Flags, 0,
+  Asm->OutStreamer->EmitDwarfLocDirective(FileNo, Line, Col, Flags, 0,
                                           Discriminator, Fn);
 }
 

lib/CodeGen/AsmPrinter/DwarfUnit.cpp

@@ -302,7 +302,9 @@ MD5::MD5Result *DwarfUnit::getMD5AsBytes(const DIFile *File) {
 unsigned DwarfTypeUnit::getOrCreateSourceID(const DIFile *File) {
   return SplitLineTable
              ? SplitLineTable->getFile(File->getDirectory(),
-                                       File->getFilename(), getMD5AsBytes(File))
+                                       File->getFilename(),
+                                       getMD5AsBytes(File),
+                                       File->getSource())
              : getCU().getOrCreateSourceID(File);
 }
 

lib/DebugInfo/DWARF/DWARFContext.cpp

@@ -466,7 +466,9 @@ void DWARFContext::dump(
     uint32_t offset = 0;
     uint32_t strOffset = 0;
     while (const char *s = strData.getCStr(&offset)) {
-      OS << format("0x%8.8x: \"%s\"\n", strOffset, s);
+      OS << format("0x%8.8x: \"", strOffset);
+      OS.write_escaped(s);
+      OS << "\"\n";
       strOffset = offset;
     }
   }

lib/DebugInfo/DWARF/DWARFDebugLine.cpp

@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
@@ -40,6 +41,28 @@ using ContentDescriptors = SmallVector<ContentDescriptor, 4>;
 
 } // end anonmyous namespace
 
+void DWARFDebugLine::ContentTypeTracker::trackContentType(
+    dwarf::LineNumberEntryFormat ContentType) {
+  switch (ContentType) {
+  case dwarf::DW_LNCT_timestamp:
+    HasModTime = true;
+    break;
+  case dwarf::DW_LNCT_size:
+    HasLength = true;
+    break;
+  case dwarf::DW_LNCT_MD5:
+    HasMD5 = true;
+    break;
+  case dwarf::DW_LNCT_LLVM_source:
+    HasSource = true;
+    break;
+  default:
+    // We only care about values we consider optional, and new values may be
+    // added in the vendor extension range, so we do not match exhaustively.
+    break;
+  }
+}
+
 DWARFDebugLine::Prologue::Prologue() { clear(); }
 
 void DWARFDebugLine::Prologue::clear() {
@@ -48,7 +71,7 @@ void DWARFDebugLine::Prologue::clear() {
   MinInstLength = MaxOpsPerInst = DefaultIsStmt = LineBase = LineRange = 0;
   OpcodeBase = 0;
   FormParams = DWARFFormParams({0, 0, DWARF32});
-  HasMD5 = false;
+  ContentTypes = ContentTypeTracker();
   StandardOpcodeLengths.clear();
   IncludeDirectories.clear();
   FileNames.clear();
@@ -85,28 +108,26 @@ void DWARFDebugLine::Prologue::dump(raw_ostream &OS,
   }
 
   if (!FileNames.empty()) {
-    if (HasMD5)
-      OS << "                Dir  MD5 Checksum                     File Name\n"
-         << "                ---- -------------------------------- -----------"
-            "---------------\n";
-    else
-      OS << "                Dir  Mod Time   File Len   File Name\n"
-         << "                ---- ---------- ---------- -----------"
-            "----------------\n";
     // DWARF v5 starts file indexes at 0.
     uint32_t FileBase = getVersion() >= 5 ? 0 : 1;
     for (uint32_t I = 0; I != FileNames.size(); ++I) {
       const FileNameEntry &FileEntry = FileNames[I];
-      OS << format("file_names[%3u] %4" PRIu64 " ", I + FileBase,
+      OS <<   format("file_names[%3u]:\n", I + FileBase);
-                   FileEntry.DirIdx);
+      OS <<          "           name: ";
-      if (HasMD5)
-        OS << FileEntry.Checksum.digest();
-      else
-        OS << format("0x%8.8" PRIx64 " 0x%8.8" PRIx64, FileEntry.ModTime,
-                     FileEntry.Length);
-      OS << ' ';
       FileEntry.Name.dump(OS, DumpOptions);
-      OS << '\n';
+      OS << '\n'
+         <<   format("      dir_index: %" PRIu64 "\n", FileEntry.DirIdx);
+      if (ContentTypes.HasMD5)
+        OS <<        "   md5_checksum: " << FileEntry.Checksum.digest() << '\n';
+      if (ContentTypes.HasModTime)
+        OS << format("       mod_time: 0x%8.8" PRIx64 "\n", FileEntry.ModTime);
+      if (ContentTypes.HasLength)
+        OS << format("         length: 0x%8.8" PRIx64 "\n", FileEntry.Length);
+      if (ContentTypes.HasSource) {
+        OS <<        "         source: ";
+        FileEntry.Source.dump(OS, DumpOptions);
+        OS << '\n';
+      }
     }
   }
 }
@@ -115,6 +136,7 @@ void DWARFDebugLine::Prologue::dump(raw_ostream &OS,
 static void
 parseV2DirFileTables(const DWARFDataExtractor &DebugLineData,
                      uint32_t *OffsetPtr, uint64_t EndPrologueOffset,
+                     DWARFDebugLine::ContentTypeTracker &ContentTypes,
                      std::vector<DWARFFormValue> &IncludeDirectories,
                      std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
   while (*OffsetPtr < EndPrologueOffset) {
@@ -138,14 +160,18 @@ parseV2DirFileTables(const DWARFDataExtractor &DebugLineData,
     FileEntry.Length = DebugLineData.getULEB128(OffsetPtr);
     FileNames.push_back(FileEntry);
   }
+
+  ContentTypes.HasModTime = true;
+  ContentTypes.HasLength = true;
 }
 
 // Parse v5 directory/file entry content descriptions.
 // Returns the descriptors, or an empty vector if we did not find a path or
 // ran off the end of the prologue.
 static ContentDescriptors
-parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr,
+parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint32_t
-                   uint64_t EndPrologueOffset, bool *HasMD5) {
+    *OffsetPtr, uint64_t EndPrologueOffset, DWARFDebugLine::ContentTypeTracker
+    *ContentTypes) {
   ContentDescriptors Descriptors;
   int FormatCount = DebugLineData.getU8(OffsetPtr);
   bool HasPath = false;
@@ -158,8 +184,8 @@ parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr,
     Descriptor.Form = dwarf::Form(DebugLineData.getULEB128(OffsetPtr));
     if (Descriptor.Type == dwarf::DW_LNCT_path)
       HasPath = true;
-    else if (Descriptor.Type == dwarf::DW_LNCT_MD5 && HasMD5)
+    if (ContentTypes)
-      *HasMD5 = true;
+      ContentTypes->trackContentType(Descriptor.Type);
     Descriptors.push_back(Descriptor);
   }
   return HasPath ? Descriptors : ContentDescriptors();
@@ -168,8 +194,9 @@ parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr,
 static bool
 parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
                      uint32_t *OffsetPtr, uint64_t EndPrologueOffset,
-                     const DWARFFormParams &FormParams, const DWARFContext &Ctx,
+                     const DWARFFormParams &FormParams, const DWARFContext
-                     const DWARFUnit *U, bool &HasMD5,
+                     &Ctx, const DWARFUnit *U,
+                     DWARFDebugLine::ContentTypeTracker &ContentTypes,
                      std::vector<DWARFFormValue> &IncludeDirectories,
                      std::vector<DWARFDebugLine::FileNameEntry> &FileNames) {
   // Get the directory entry description.
@@ -200,7 +227,8 @@ parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
 
   // Get the file entry description.
   ContentDescriptors FileDescriptors =
-      parseV5EntryFormat(DebugLineData, OffsetPtr, EndPrologueOffset, &HasMD5);
+      parseV5EntryFormat(DebugLineData, OffsetPtr, EndPrologueOffset,
+          &ContentTypes);
   if (FileDescriptors.empty())
     return false;
 
@@ -218,6 +246,9 @@ parseV5DirFileTables(const DWARFDataExtractor &DebugLineData,
       case DW_LNCT_path:
         FileEntry.Name = Value;
         break;
+      case DW_LNCT_LLVM_source:
+        FileEntry.Source = Value;
+        break;
       case DW_LNCT_directory_index:
         FileEntry.DirIdx = Value.getAsUnsignedConstant().getValue();
         break;
@@ -285,8 +316,8 @@ bool DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
 
   if (getVersion() >= 5) {
     if (!parseV5DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
-                              FormParams, Ctx, U, HasMD5, IncludeDirectories,
+                              FormParams, Ctx, U, ContentTypes,
-                              FileNames)) {
+                              IncludeDirectories, FileNames)) {
       fprintf(stderr,
               "warning: parsing line table prologue at 0x%8.8" PRIx64
               " found an invalid directory or file table description at"
@@ -295,7 +326,7 @@ bool DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
     }
   } else
     parseV2DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
-                         IncludeDirectories, FileNames);
+                         ContentTypes, IncludeDirectories, FileNames);
 
   if (*OffsetPtr != EndPrologueOffset) {
     fprintf(stderr,
@@ -912,6 +943,16 @@ bool DWARFDebugLine::LineTable::hasFileAtIndex(uint64_t FileIndex) const {
   return FileIndex != 0 && FileIndex <= Prologue.FileNames.size();
 }
 
+Optional<StringRef> DWARFDebugLine::LineTable::getSourceByIndex(uint64_t FileIndex,
+                                                                FileLineInfoKind Kind) const {
+  if (Kind == FileLineInfoKind::None || !hasFileAtIndex(FileIndex))
+    return None;
+  const FileNameEntry &Entry = Prologue.FileNames[FileIndex - 1];
+  if (Optional<const char *> source = Entry.Source.getAsCString())
+    return StringRef(*source);
+  return None;
+}
+
 bool DWARFDebugLine::LineTable::getFileNameByIndex(uint64_t FileIndex,
                                                    const char *CompDir,
                                                    FileLineInfoKind Kind,
@@ -963,5 +1004,6 @@ bool DWARFDebugLine::LineTable::getFileLineInfoForAddress(
   Result.Line = Row.Line;
   Result.Column = Row.Column;
   Result.Discriminator = Row.Discriminator;
+  Result.Source = getSourceByIndex(Row.File, Kind);
   return true;
 }

lib/IR/AsmWriter.cpp

@@ -1723,6 +1723,8 @@ static void writeDIFile(raw_ostream &Out, const DIFile *N, TypePrinting *,
   // Print all values for checksum together, or not at all.
   if (N->getChecksum())
     Printer.printChecksum(*N->getChecksum());
+  Printer.printString("source", N->getSource().getValueOr(StringRef()),
+                      /* ShouldSkipEmpty */ true);
   Out << ")";
 }
 

lib/IR/DIBuilder.cpp

@@ -14,6 +14,7 @@
 #include "llvm/IR/DIBuilder.h"
 #include "llvm/IR/IRBuilder.h"
 #include "LLVMContextImpl.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/IR/Constants.h"
@@ -204,8 +205,9 @@ DIImportedEntity *DIBuilder::createImportedDeclaration(DIScope *Context,
 }
 
 DIFile *DIBuilder::createFile(StringRef Filename, StringRef Directory,
-                              Optional<DIFile::ChecksumInfo<StringRef>> CS) {
+                              Optional<DIFile::ChecksumInfo<StringRef>> CS,
-  return DIFile::get(VMContext, Filename, Directory, CS);
+                              Optional<StringRef> Source) {
+  return DIFile::get(VMContext, Filename, Directory, CS, Source);
 }
 
 DIMacro *DIBuilder::createMacro(DIMacroFile *Parent, unsigned LineNumber,

lib/IR/DebugInfoMetadata.cpp

@@ -417,13 +417,16 @@ Optional<DIFile::ChecksumKind> DIFile::getChecksumKind(StringRef CSKindStr) {
 DIFile *DIFile::getImpl(LLVMContext &Context, MDString *Filename,
                         MDString *Directory,
                         Optional<DIFile::ChecksumInfo<MDString *>> CS,
-                        StorageType Storage, bool ShouldCreate) {
+                        Optional<MDString *> Source, StorageType Storage,
+                        bool ShouldCreate) {
   assert(isCanonical(Filename) && "Expected canonical MDString");
   assert(isCanonical(Directory) && "Expected canonical MDString");
   assert((!CS || isCanonical(CS->Value)) && "Expected canonical MDString");
-  DEFINE_GETIMPL_LOOKUP(DIFile, (Filename, Directory, CS));
+  assert((!Source || isCanonical(*Source)) && "Expected canonical MDString");
-  Metadata *Ops[] = {Filename, Directory, CS ? CS->Value : nullptr};
+  DEFINE_GETIMPL_LOOKUP(DIFile, (Filename, Directory, CS, Source));
-  DEFINE_GETIMPL_STORE(DIFile, (CS), Ops);
+  Metadata *Ops[] = {Filename, Directory, CS ? CS->Value : nullptr,
+                     Source.getValueOr(nullptr)};
+  DEFINE_GETIMPL_STORE(DIFile, (CS, Source), Ops);
 }
 
 DICompileUnit *DICompileUnit::getImpl(

lib/IR/LLVMContextImpl.h

@@ -575,24 +575,28 @@ template <> struct MDNodeKeyImpl<DIFile> {
   MDString *Filename;
   MDString *Directory;
   Optional<DIFile::ChecksumInfo<MDString *>> Checksum;
+  Optional<MDString *> Source;
 
   MDNodeKeyImpl(MDString *Filename, MDString *Directory,
-                Optional<DIFile::ChecksumInfo<MDString *>> Checksum)
+                Optional<DIFile::ChecksumInfo<MDString *>> Checksum,
-      : Filename(Filename), Directory(Directory), Checksum(Checksum) {}
+                Optional<MDString *> Source)
+      : Filename(Filename), Directory(Directory), Checksum(Checksum),
+        Source(Source) {}
   MDNodeKeyImpl(const DIFile *N)
       : Filename(N->getRawFilename()), Directory(N->getRawDirectory()),
-        Checksum(N->getRawChecksum()) {}
+        Checksum(N->getRawChecksum()), Source(N->getRawSource()) {}
 
   bool isKeyOf(const DIFile *RHS) const {
     return Filename == RHS->getRawFilename() &&
            Directory == RHS->getRawDirectory() &&
-           Checksum == RHS->getRawChecksum();
+           Checksum == RHS->getRawChecksum() &&
+           Source == RHS->getRawSource();
   }
 
   unsigned getHashValue() const {
-    if (Checksum)
+    return hash_combine(
-      return hash_combine(Filename, Directory, Checksum->Kind, Checksum->Value);
+        Filename, Directory, Checksum ? Checksum->Kind : 0,
-    return hash_combine(Filename, Directory);
+        Checksum ? Checksum->Value : nullptr, Source.getValueOr(nullptr));
   }
 };
 

lib/MC/MCAsmStreamer.cpp

@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
@@ -215,6 +216,7 @@ public:
                                                StringRef Directory,
                                                StringRef Filename,
                                                MD5::MD5Result *Checksum = 0,
+                                               Optional<StringRef> Source = None,
                                                unsigned CUID = 0) override;
   void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
                              unsigned Column, unsigned Flags,
@@ -1076,13 +1078,13 @@ void MCAsmStreamer::EmitFileDirective(StringRef Filename) {
 
 Expected<unsigned> MCAsmStreamer::tryEmitDwarfFileDirective(
     unsigned FileNo, StringRef Directory, StringRef Filename,
-    MD5::MD5Result *Checksum, unsigned CUID) {
+    MD5::MD5Result *Checksum, Optional<StringRef> Source, unsigned CUID) {
   assert(CUID == 0);
 
   MCDwarfLineTable &Table = getContext().getMCDwarfLineTable(CUID);
   unsigned NumFiles = Table.getMCDwarfFiles().size();
   Expected<unsigned> FileNoOrErr =
-      Table.tryGetFile(Directory, Filename, Checksum, FileNo);
+      Table.tryGetFile(Directory, Filename, Checksum, Source, FileNo);
   if (!FileNoOrErr)
     return FileNoOrErr.takeError();
   FileNo = FileNoOrErr.get();
@@ -1114,6 +1116,10 @@ Expected<unsigned> MCAsmStreamer::tryEmitDwarfFileDirective(
     OS1 << " md5 ";
     PrintQuotedString(Checksum->digest(), OS1);
   }
+  if (Source) {
+    OS1 << " source ";
+    PrintQuotedString(*Source, OS1);
+  }
   if (MCTargetStreamer *TS = getTargetStreamer()) {
     TS->emitDwarfFileDirective(OS1.str());
   } else {

lib/MC/MCContext.cpp

@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/MC/MCContext.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
@@ -532,7 +533,7 @@ MCSubtargetInfo &MCContext::getSubtargetCopy(const MCSubtargetInfo &STI) {
 // Dwarf Management
 //===----------------------------------------------------------------------===//
 
-/// getDwarfFile - takes a file name an number to place in the dwarf file and
+/// getDwarfFile - takes a file name and 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.
@@ -540,9 +541,10 @@ Expected<unsigned> MCContext::getDwarfFile(StringRef Directory,
                                            StringRef FileName,
                                            unsigned FileNumber,
                                            MD5::MD5Result *Checksum,
+                                           Optional<StringRef> Source,
                                            unsigned CUID) {
   MCDwarfLineTable &Table = MCDwarfLineTablesCUMap[CUID];
-  return Table.tryGetFile(Directory, FileName, Checksum, FileNumber);
+  return Table.tryGetFile(Directory, FileName, Checksum, Source, FileNumber);
 }
 
 /// isValidDwarfFileNumber - takes a dwarf file number and returns true if it

lib/MC/MCDwarf.cpp

@@ -11,7 +11,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Hashing.h"
-#include "llvm/ADT/None.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
@@ -373,8 +373,13 @@ void MCDwarfLineTableHeader::emitV5FileDirTables(
 
   // The file format, which is the inline null-terminated filename and a
   // directory index.  We don't track file size/timestamp so don't emit them
-  // in the v5 table.  Emit MD5 checksums if we have them.
+  // in the v5 table.  Emit MD5 checksums and source if we have them.
-  MCOS->EmitIntValue(HasMD5 ? 3 : 2, 1);
+  uint64_t Entries = 2;
+  if (HasMD5)
+    Entries += 1;
+  if (HasSource)
+    Entries += 1;
+  MCOS->EmitIntValue(Entries, 1);
   MCOS->EmitULEB128IntValue(dwarf::DW_LNCT_path);
   MCOS->EmitULEB128IntValue(LineStr ? dwarf::DW_FORM_line_strp
                                     : dwarf::DW_FORM_string);
@@ -384,6 +389,11 @@ void MCDwarfLineTableHeader::emitV5FileDirTables(
     MCOS->EmitULEB128IntValue(dwarf::DW_LNCT_MD5);
     MCOS->EmitULEB128IntValue(dwarf::DW_FORM_data16);
   }
+  if (HasSource) {
+    MCOS->EmitULEB128IntValue(dwarf::DW_LNCT_LLVM_source);
+    MCOS->EmitULEB128IntValue(LineStr ? dwarf::DW_FORM_line_strp
+                                      : dwarf::DW_FORM_string);
+  }
   // Then the list of file names. These start at 1.
   MCOS->EmitULEB128IntValue(MCDwarfFiles.size() - 1);
   for (unsigned i = 1; i < MCDwarfFiles.size(); ++i) {
@@ -401,6 +411,15 @@ void MCDwarfLineTableHeader::emitV5FileDirTables(
           StringRef(reinterpret_cast<const char *>(Cksum->Bytes.data()),
                     Cksum->Bytes.size()));
     }
+    if (HasSource) {
+      if (LineStr)
+        LineStr->emitRef(MCOS, MCDwarfFiles[i].Source.getValueOr(StringRef()));
+      else {
+        MCOS->EmitBytes(
+            MCDwarfFiles[i].Source.getValueOr(StringRef())); // Source and...
+        MCOS->EmitBytes(StringRef("\0", 1)); // its null terminator.
+      }
+    }
   }
 }
 
@@ -500,14 +519,17 @@ void MCDwarfLineTable::EmitCU(MCObjectStreamer *MCOS,
 Expected<unsigned> MCDwarfLineTable::tryGetFile(StringRef &Directory,
                                                 StringRef &FileName,
                                                 MD5::MD5Result *Checksum,
+                                                Optional<StringRef> Source,
                                                 unsigned FileNumber) {
-  return Header.tryGetFile(Directory, FileName, Checksum, FileNumber);
+  return Header.tryGetFile(Directory, FileName, Checksum, Source, FileNumber);
 }
 
-Expected<unsigned> MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
+Expected<unsigned>
-                                                      StringRef &FileName,
+MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
-                                                      MD5::MD5Result *Checksum,
+                                   StringRef &FileName,
-                                                      unsigned FileNumber) {
+                                   MD5::MD5Result *Checksum,
+                                   Optional<StringRef> &Source,
+                                   unsigned FileNumber) {
   if (Directory == CompilationDir)
     Directory = "";
   if (FileName.empty()) {
@@ -515,9 +537,11 @@ Expected<unsigned> MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
     Directory = "";
   }
   assert(!FileName.empty());
-  // If any files have an MD5 checksum, they all must.
+  // If any files have an MD5 checksum or embedded source, they all must.
-  if (MCDwarfFiles.empty())
+  if (MCDwarfFiles.empty()) {
     HasMD5 = (Checksum != nullptr);
+    HasSource = (Source != None);
+  }
   if (FileNumber == 0) {
     // File numbers start with 1 and/or after any file numbers
     // allocated by inline-assembler .file directives.
@@ -545,6 +569,10 @@ Expected<unsigned> MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
   if (HasMD5 != (Checksum != nullptr))
     return make_error<StringError>("inconsistent use of MD5 checksums",
                                    inconvertibleErrorCode());
+  // If any files have embedded source, they all must.
+  if (HasSource != (Source != None))
+    return make_error<StringError>("inconsistent use of embedded source",
+                                   inconvertibleErrorCode());
 
   if (Directory.empty()) {
     // Separate the directory part from the basename of the FileName.
@@ -582,6 +610,9 @@ Expected<unsigned> MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
   File.Checksum = Checksum;
   if (Checksum)
     HasMD5 = true;
+  File.Source = Source;
+  if (Source)
+    HasSource = true;
 
   // return the allocated FileNumber.
   return FileNumber;

lib/MC/MCParser/AsmParser.cpp

@@ -3250,7 +3250,7 @@ bool AsmParser::parseDirectiveAlign(bool IsPow2, unsigned ValueSize) {
 
 /// parseDirectiveFile
 /// ::= .file filename
-/// ::= .file number [directory] filename [md5 checksum]
+/// ::= .file number [directory] filename [md5 checksum] [source source-text]
 bool AsmParser::parseDirectiveFile(SMLoc DirectiveLoc) {
   // FIXME: I'm not sure what this is.
   int64_t FileNumber = -1;
@@ -3286,23 +3286,36 @@ bool AsmParser::parseDirectiveFile(SMLoc DirectiveLoc) {
   }
 
   std::string Checksum;
-  if (!parseOptionalToken(AsmToken::EndOfStatement)) {
+
+  Optional<StringRef> Source;
+  bool HasSource = false;
+  std::string SourceString;
+
+  while (!parseOptionalToken(AsmToken::EndOfStatement)) {
     StringRef Keyword;
     if (check(getTok().isNot(AsmToken::Identifier),
               "unexpected token in '.file' directive") ||
-        parseIdentifier(Keyword) ||
+        parseIdentifier(Keyword))
-        check(Keyword != "md5", "unexpected token in '.file' directive"))
-      return true;
-    if (getLexer().is(AsmToken::String) &&
-        check(FileNumber == -1, "MD5 checksum specified, but no file number"))
-      return true;
-    if (check(getTok().isNot(AsmToken::String),
-              "unexpected token in '.file' directive") ||
-        parseEscapedString(Checksum) ||
-        check(Checksum.size() != 32, "invalid MD5 checksum specified") ||
-        parseToken(AsmToken::EndOfStatement,
-                   "unexpected token in '.file' directive"))
       return true;
+    if (Keyword == "md5") {
+      if (check(FileNumber == -1,
+                "MD5 checksum specified, but no file number") ||
+          check(getTok().isNot(AsmToken::String),
+                "unexpected token in '.file' directive") ||
+          parseEscapedString(Checksum) ||
+          check(Checksum.size() != 32, "invalid MD5 checksum specified"))
+        return true;
+    } else if (Keyword == "source") {
+      HasSource = true;
+      if (check(FileNumber == -1,
+                "source specified, but no file number") ||
+          check(getTok().isNot(AsmToken::String),
+                "unexpected token in '.file' directive") ||
+          parseEscapedString(SourceString))
+        return true;
+    } else {
+      return TokError("unexpected token in '.file' directive");
+    }
   }
 
   if (FileNumber == -1)
@@ -3316,13 +3329,18 @@ bool AsmParser::parseDirectiveFile(SMLoc DirectiveLoc) {
       CKMem = (MD5::MD5Result *)Ctx.allocate(sizeof(MD5::MD5Result), 1);
       memcpy(&CKMem->Bytes, Checksum.data(), 16);
     }
+    if (HasSource) {
+      char *SourceBuf = static_cast<char *>(Ctx.allocate(SourceString.size()));
+      memcpy(SourceBuf, SourceString.data(), SourceString.size());
+      Source = StringRef(SourceBuf, SourceString.size());
+    }
     // If there is -g option as well as debug info from directive file,
     // we turn off -g option, directly use the existing debug info instead.
     if (getContext().getGenDwarfForAssembly())
       getContext().setGenDwarfForAssembly(false);
     else {
       Expected<unsigned> FileNumOrErr = getStreamer().tryEmitDwarfFileDirective(
-          FileNumber, Directory, Filename, CKMem);
+          FileNumber, Directory, Filename, CKMem, Source);
       if (!FileNumOrErr)
         return Error(DirectiveLoc, toString(FileNumOrErr.takeError()));
       FileNumber = FileNumOrErr.get();

lib/MC/MCStreamer.cpp

@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/MC/MCStreamer.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
@@ -191,8 +192,11 @@ void MCStreamer::EmitZeros(uint64_t NumBytes) {
 Expected<unsigned>
 MCStreamer::tryEmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
                                       StringRef Filename,
-                                      MD5::MD5Result *Checksum, unsigned CUID) {
+                                      MD5::MD5Result *Checksum,
-  return getContext().getDwarfFile(Directory, Filename, FileNo, Checksum, CUID);
+                                      Optional<StringRef> Source,
+                                      unsigned CUID) {
+  return getContext().getDwarfFile(Directory, Filename, FileNo, Checksum,
+                                   Source, CUID);
 }
 
 void MCStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,

test/Assembler/debug-info.ll

@@ -1,8 +1,8 @@
 ; RUN: llvm-as < %s | llvm-dis | llvm-as | llvm-dis | FileCheck %s
 ; RUN: verify-uselistorder %s
 
-; CHECK: !named = !{!0, !0, !1, !2, !3, !4, !5, !6, !7, !8, !8, !9, !10, !11, !12, !13, !14, !15, !16, !17, !18, !19, !20, !21, !22, !23, !24, !25, !26, !27, !27, !28, !29, !30, !31, !32, !33, !34, !35}
+; CHECK: !named = !{!0, !0, !1, !2, !3, !4, !5, !6, !7, !8, !8, !9, !10, !11, !12, !13, !14, !15, !16, !17, !18, !19, !20, !21, !22, !23, !24, !25, !26, !27, !27, !28, !29, !30, !31, !32, !33, !34, !35, !36, !37}
-!named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9, !10, !11, !12, !13, !14, !15, !16, !17, !18, !19, !20, !21, !22, !23, !24, !25, !26, !27, !28, !29, !30, !31, !32, !33, !34, !35, !36, !37, !38}
+!named = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9, !10, !11, !12, !13, !14, !15, !16, !17, !18, !19, !20, !21, !22, !23, !24, !25, !26, !27, !28, !29, !30, !31, !32, !33, !34, !35, !36, !37, !38, !39, !40}
 
 ; CHECK:      !0 = !DISubrange(count: 3)
 ; CHECK-NEXT: !1 = !DISubrange(count: 3, lowerBound: 4)
@@ -89,3 +89,8 @@
 !36 = !DICompositeType(tag: DW_TAG_variant_part, name: "A", scope: !16, size: 64, discriminator: !37)
 !37 = !DIDerivedType(tag: DW_TAG_member, scope: !36, baseType: !38, size: 64, align: 64, flags: DIFlagArtificial)
 !38 = !DIBasicType(name: "u64", size: 64, encoding: DW_ATE_unsigned)
+
+; CHECK-NEXT: !36 = !DIFile(filename: "file", directory: "dir", source: "int source() { }\0A")
+; CHECK-NEXT: !37 = !DIFile(filename: "file", directory: "dir", checksumkind: CSK_MD5, checksum: "3a420e2646916a475e68de8d48f779f5", source: "int source() { }\0A")
+!39 = !DIFile(filename: "file", directory: "dir", source: "int source() { }\0A")
+!40 = !DIFile(filename: "file", directory: "dir", checksumkind: CSK_MD5, checksum: "3a420e2646916a475e68de8d48f779f5", source: "int source() { }\0A")

test/CodeGen/BPF/dwarfdump.ll

@@ -59,6 +59,8 @@ attributes #1 = { nounwind readnone }
 !26 = !DILocation(line: 7, column: 17, scope: !2)
 !27 = !DILocation(line: 9, column: 9, scope: !2)
 
-; CHECK: file_names[  1]    0 0x00000000 0x00000000 "testprog.c"
+; CHECK: file_names[  1]:
+; CHECK-NEXT: name: "testprog.c"
+; CHECK-NEXT: dir_index: 0
 ; CHECK: 0x0000000000000000      2
 ; CHECK: 0x0000000000000028      7

test/CodeGen/Generic/dwarf-md5.ll

@@ -16,13 +16,21 @@
 ; ASM: .file 1 ".{{/|\\\\}}t1.h" md5 "11111111111111111111111111111111"
 ; ASM: .file 2 ".{{/|\\\\}}t2.h" md5 "22222222222222222222222222222222"
 
-; OBJ-4: Dir Mod Time File Len File Name
+; OBJ-4: file_names[ 1]:
-; OBJ-4: file_names[ 1] 1 0x00000000 0x00000000 "t1.h"
+; OBJ-4-NEXT: name: "t1.h"
-; OBJ-4: file_names[ 2] 1 0x00000000 0x00000000 "t2.h"
+; OBJ-4-NEXT: dir_index: 1
+; OBJ-4: file_names[ 2]:
+; OBJ-4-NEXT: name: "t2.h"
+; OBJ-4-NEXT: dir_index: 1
 
-; OBJ-5: Dir MD5 Checksum File Name
+; OBJ-5: file_names[ 0]:
-; OBJ-5: file_names[ 0] 1 11111111111111111111111111111111 "t1.h"
+; OBJ-5-NEXT: name: "t1.h"
-; OBJ-5: file_names[ 1] 1 22222222222222222222222222222222 "t2.h"
+; OBJ-5-NEXT: dir_index: 1
+; OBJ-5-NEXT: md5_checksum: 11111111111111111111111111111111
+; OBJ-5: file_names[ 1]:
+; OBJ-5-NEXT: name: "t2.h"
+; OBJ-5-NEXT: dir_index: 1
+; OBJ-5-NEXT: md5_checksum: 22222222222222222222222222222222
 
 ; ModuleID = 't.c'
 source_filename = "t.c"

test/CodeGen/X86/dwarf-comp-dir.ll

@@ -15,7 +15,7 @@ target triple = "x86_64-unknown-linux-gnu"
 !7 = !{!6}
 
 ; The important part of the following check is that dir = #0.
-;                        Dir  Mod Time   File Len   File Name
+; CHECK: file_names[  1]:
-;                        ---- ---------- ---------- ---------------------------
+; CHECK-NEXT: name: "empty.c"
-; CHECK: file_names[  1]    0 0x00000000 0x00000000 "empty.c"
+; CHECK-NEXT: dir_index: 0
 !5 = !{i32 1, !"Debug Info Version", i32 3}

test/DebugInfo/AMDGPU/dwarfdump-relocs.ll

@@ -13,7 +13,9 @@
 ; }
 
 ; CHECK-NOT: failed to compute relocation
-; CHECK: file_names[  1] 0 0x00000000 0x00000000 "dwarfdump-relocs.cl"
+; CHECK: file_names[  1]:
+; CHECK-NEXT: name: "dwarfdump-relocs.cl"
+; CHECK-NEXT: dir_index: 0
 
 declare void @llvm.dbg.declare(metadata, metadata, metadata)
 

test/DebugInfo/Generic/lto-comp-dir.ll

@@ -11,13 +11,17 @@
 ; CHECK-NEXT: debug_line[{{.*}}]
 ; CHECK-NEXT: Line table prologue:
 ; CHECK-NOT: include_directories
-; CHECK: file_names[   1]   0 {{.*}} "a.cpp"
+; CHECK: file_names[   1]
+; CHECK: name: "a.cpp"
+; CHECK-NEXT: dir_index: 0
 ; CHECK-NOT: file_names
 
 ; CHECK: debug_line[{{.*}}]
 ; CHECK-NEXT: Line table prologue:
 ; CHECK-NOT: include_directories
-; CHECK: file_names[   1]   0 {{.*}} "b.cpp"
+; CHECK: file_names[   1]
+; CHECK: name: "b.cpp"
+; CHECK-NEXT: dir_index: 0
 ; CHECK-NOT: file_names
 
 ; However, if a single line table is emitted and shared between CUs, the

test/DebugInfo/X86/debug-macro.ll

@@ -28,11 +28,12 @@
 ; CHECK-NEXT: DW_MACINFO_end_file
 
 ; CHECK-LABEL: .debug_line contents:
-; CHECK: Dir  Mod Time   File Len   File Name
+; CHECK: file_names[  1]:
-; CHECK: file_names[  1] {{.*}}debug-macro.cpp
+; CHECK: name: "debug-macro.cpp"
-; CHECK: file_names[  2] {{.*}}debug-macro.h
+; CHECK: file_names[  2]:
-; CHECK: Dir  Mod Time   File Len   File Name
+; CHECK: name: "debug-macro.h"
-; CHECK: file_names[  1] {{.*}}debug-macro1.cpp
+; CHECK: file_names[  1]:
+; CHECK: name: "debug-macro1.cpp"
 
 !llvm.dbg.cu = !{!0, !16, !20}
 !llvm.module.flags = !{!13, !14}

test/DebugInfo/X86/dwarfdump-header-64.s

@@ -144,6 +144,14 @@ LH_5_end:
 # CHECK: include_directories[  0] = .debug_str[0x00000028] = "Directory5a"
 # CHECK: include_directories[  1] = .debug_str[0x00000034] = "Directory5b"
 # CHECK-NOT: include_directories
-# CHECK: file_names[  0]    0 0x00000051 0x00000052 "File5a"
+# CHECK: file_names[  0]:
-# CHECK: file_names[  1]    1 0x00000053 0x00000054 "File5b"
+# CHECK-NEXT: name: "File5a"
+# CHECK-NEXT: dir_index: 0
+# CHECK-NEXT: mod_time: 0x00000051
+# CHECK-NEXT: length: 0x00000052
+# CHECK: file_names[  1]:
+# CHECK-NEXT: name: "File5b"
+# CHECK-NEXT: dir_index: 1
+# CHECK-NEXT: mod_time: 0x00000053
+# CHECK-NEXT: length: 0x00000054
 # CHECK-NOT: file_names

test/DebugInfo/X86/dwarfdump-header.s

@@ -258,8 +258,16 @@ LH_4_end:
 # CHECK: include_directories[  1] = "Directory4a"
 # CHECK: include_directories[  2] = "Directory4b"
 # CHECK-NOT: include_directories
-# CHECK: file_names[  1]    1 0x00000041 0x00000042 "File4a"
+# CHECK: file_names[  1]:
-# CHECK: file_names[  2]    0 0x00000043 0x00000044 "File4b"
+# CHECK-NEXT: name: "File4a"
+# CHECK-NEXT: dir_index: 1
+# CHECK-NEXT: mod_time: 0x00000041
+# CHECK-NEXT: length: 0x00000042
+# CHECK: file_names[  2]:
+# CHECK-NEXT: name: "File4b"
+# CHECK-NEXT: dir_index: 0
+# CHECK-NEXT: mod_time: 0x00000043
+# CHECK-NEXT: length: 0x00000044
 # CHECK-NOT: file_names
 
 # DWARF v5 line-table header.
@@ -329,9 +337,14 @@ LH_5_end:
 # CHECK: include_directories[  0] = .debug_str[0x00000045] = "Directory5a"
 # CHECK: include_directories[  1] = .debug_str[0x00000051] = "Directory5b"
 # CHECK-NOT: include_directories
-# CHECK: MD5 Checksum
+# CHECK: file_names[  0]:
-# CHECK: file_names[  0]    0 00112233445566778899aabbccddeeff .debug_line_str[0x00000000] = "File5a"
+# CHECK-NEXT: name: .debug_line_str[0x00000000] = "File5a"
-# CHECK: file_names[  1]    1 ffeeddccbbaa99887766554433221100 .debug_line_str[0x00000007] = "File5b"
+# CHECK-NEXT: dir_index: 0
+# CHECK-NEXT: md5_checksum: 00112233445566778899aabbccddeeff
+# CHECK: file_names[  1]:
+# CHECK-NEXT: name: .debug_line_str[0x00000007] = "File5b"
+# CHECK-NEXT: dir_index: 1
+# CHECK-NEXT: md5_checksum: ffeeddccbbaa99887766554433221100
 # CHECK-NOT: file_names
 
         .section .debug_line_str,"MS",@progbits,1
@@ -410,6 +423,14 @@ dwo_LH_5_end:
 # CHECK: include_directories[  0] = .debug_str[0x0000003d] = "DWODirectory5a"
 # CHECK: include_directories[  1] = .debug_str[0x0000004c] = "DWODirectory5b"
 # CHECK-NOT: include_directories
-# CHECK: file_names[  0]    0 0x00000015 0x00000025 "DWOFile5a"
+# CHECK: file_names[  0]:
-# CHECK: file_names[  1]    1 0x00000035 0x00000045 "DWOFile5b"
+# CHECK-NEXT: name: "DWOFile5a"
+# CHECK-NEXT: dir_index: 0
+# CHECK-NEXT: mod_time: 0x00000015
+# CHECK-NEXT: length: 0x00000025
+# CHECK: file_names[  1]:
+# CHECK-NEXT: name: "DWOFile5b"
+# CHECK-NEXT: dir_index: 1
+# CHECK-NEXT: mod_time: 0x00000035
+# CHECK-NEXT: length: 0x00000045
 # CHECK-NOT: file_names

test/DebugInfo/X86/dwarfdump-line-dwo.s

@@ -47,7 +47,8 @@ LH_1_end:
 # PART1-NEXT: version: 4
 # PART1-NEXT: prologue_length: 0x00000028
 # PART1:      include_directories[  1] = "Directory1"
-# PART1:      file_names[  1] {{.*}} "File1"
+# PART1:      file_names[  1]
+# PART1:      name: "File1"
 
 # Second line table.
 LH_2_start:
@@ -93,5 +94,6 @@ LH_2_end:
 # PART2-NEXT: prologue_length: 0x00000022
 # PART2-NOT:  prologue:
 # PART2:      include_directories[  1] = "Dir2"
-# PART2:      file_names[  1] {{.*}} "File2"
+# PART2:      file_names[  1]
+# PART2:      name: "File2"
 # PART2-NOT:  prologue:

test/DebugInfo/X86/dwarfdump-line-only.s

@@ -94,7 +94,15 @@ ls_F2:  .asciz "File2"
 # CHECK: include_directories[  0] = .debug_str[0x00000000] = "Directory1"
 # CHECK: include_directories[  1] = .debug_str[0x0000000b] = "Directory2"
 # CHECK-NOT: include_directories
-# CHECK: file_names[  0]    1 0x00000051 0x00000052 .debug_line_str[0x00000000] = "File1"
+# CHECK: file_names[  0]:
-# CHECK: file_names[  1]    0 0x00000053 0x00000054 .debug_line_str[0x00000006] = "File2"
+# CHECK-NEXT: name: .debug_line_str[0x00000000] = "File1"
+# CHECK-NEXT: dir_index: 1
+# CHECK-NEXT: mod_time: 0x00000051
+# CHECK-NEXT: length: 0x00000052
+# CHECK: file_names[  1]:
+# CHECK-NEXT: name: .debug_line_str[0x00000006] = "File2"
+# CHECK-NEXT: dir_index: 0
+# CHECK-NEXT: mod_time: 0x00000053
+# CHECK-NEXT: length: 0x00000054
 # CHECK-NOT: file_names
 # CHECK: 0x0000000000000000 {{.*}} is_stmt end_sequence

test/DebugInfo/X86/generate-odr-hash.ll

@@ -122,8 +122,10 @@
 ; CHECK-LABEL: .debug_line contents:
 ; CHECK: Line table prologue
 ; CHECK-NOT: file_names[
-; SINGLE: file_names{{.*}} "bar.h"
+; SINGLE: file_names[
-; CHECK: file_names{{.*}} "bar.cpp"
+; SINGLE-NEXT: name: "bar.h"
+; CHECK: file_names[
+; CHECK-NEXT: name: "bar.cpp"
 ; CHECK-NOT: file_names[
 
 ; FISSION: .debug_line.dwo contents:
@@ -133,8 +135,10 @@
 ; FISSION-NOT: standard_opcode_lengths
 ; FISSION-NOT: include_directories
 ; FISSION-NOT: file_names[
-; FISSION: file_names{{.*}} "bar.h"
+; FISSION: file_names[
-; FISSION: file_names{{.*}} "bar.cpp"
+; FISSION-NEXT: name: "bar.h"
+; FISSION: file_names[
+; FISSION-NEXT: name: "bar.cpp"
 ; FISSION-NOT: file_names[
 
 ; CHECK-LABEL: .debug_str contents:

test/DebugInfo/X86/stmt-list-multiple-compile-units.ll

@@ -27,11 +27,15 @@
 ; CHECK-NEXT: debug_line[{{.*}}]
 ; CHECK-NEXT: Line table prologue:
 ; CHECK-NEXT: total_length: 0x00000038
-; CHECK: file_names[  1]    0 0x00000000 0x00000000 "simple.c"
+; CHECK: file_names[  1]:
+; CHECK-NEXT: name: "simple.c"
+; CHECK-NEXT: dir_index: 0
 ; CHECK: debug_line[{{.*}}]
 ; CHECK-NEXT: Line table prologue:
 ; CHECK-NEXT: total_length: 0x00000039
-; CHECK: file_names[  1]    0 0x00000000 0x00000000 "simple2.c"
+; CHECK: file_names[  1]:
+; CHECK-NEXT: name: "simple2.c"
+; CHECK-NEXT: dir_index: 0
 ; CHECK-NOT: file_names
 
 ; DWARF3: .debug_info contents:
@@ -46,11 +50,15 @@
 ; DWARF3-NEXT: debug_line[{{.*}}]
 ; DWARF3-NEXT: Line table prologue:
 ; DWARF3-NEXT: total_length: 0x00000038
-; DWARF3: file_names[  1]    0 0x00000000 0x00000000 "simple.c"
+; DWARF3: file_names[  1]:
+; DWARF3-NEXT: name: "simple.c"
+; DWARF3-NEXT: dir_index: 0
 ; DWARF3: debug_line[{{.*}}]
 ; DWARF3-NEXT: Line table prologue:
 ; DWARF3-NEXT: total_length: 0x00000039
-; DWARF3: file_names[  1]    0 0x00000000 0x00000000 "simple2.c"
+; DWARF3: file_names[  1]:
+; DWARF3-NEXT: name: "simple2.c"
+; DWARF3-NEXT: dir_index: 0
 ; DWARF3-NOT: file_names
 
 ; PR15408

test/DebugInfo/debugmacinfo.test

@@ -22,6 +22,12 @@ TEST_MACINFO:   DW_MACINFO_define - lineno: 3 macro: M2(x,y) ((x)+(y)* Value2)
 TEST_MACINFO: DW_MACINFO_end_file
 
 TEST_LINE: .debug_line contents:
-TEST_LINE: file_names[  1]    0 0x00000000 0x00000000 "dwarfdump-macro.cc"
+TEST_LINE: file_names[  1]:
-TEST_LINE: file_names[  2]    1 0x00000000 0x00000000 "dwarfdump-macro-cmd.h"
+TEST_LINE-NEXT: name: "dwarfdump-macro.cc"
-TEST_LINE: file_names[  3]    0 0x00000000 0x00000000 "dwarfdump-macro.h"
+TEST_LINE-NEXT: dir_index: 0
+TEST_LINE: file_names[  2]:
+TEST_LINE-NEXT: name: "dwarfdump-macro-cmd.h"
+TEST_LINE-NEXT: dir_index: 1
+TEST_LINE: file_names[  3]:
+TEST_LINE-NEXT: name: "dwarfdump-macro.h"
+TEST_LINE-NEXT: dir_index: 0

test/Linker/subprogram-linkonce-weak.ll

@@ -147,14 +147,18 @@ entry:
 ; DW-LABEL:   .debug_line contents:
 ; Check that we have the right things in the line table as well.
 
-; DWLW-LABEL: file_names[{{ *}}1]{{.*}} "bar.c"
+; DWLW-LABEL: file_names[ 1]:
+; DWLW-NEXT: name: "bar.c"
 ; DWLW:        2 0 1 0 0 is_stmt prologue_end
-; DWLW-LABEL: file_names[{{ *}}1]{{.*}} "foo.c"
+; DWLW-LABEL: file_names[ 1]:
+; DWLW-NEXT: name: "foo.c"
 ; DWLW:       52 0 1 0 0 is_stmt prologue_end
 ; DWLW-NOT:                      prologue_end
 
-; DWWL-LABEL: file_names[{{ *}}1]{{.*}} "foo.c"
+; DWWL-LABEL: file_names[ 1]:
+; DWWL-NEXT: name: "foo.c"
 ; DWWL:       52 0 1 0 0 is_stmt prologue_end
-; DWWL-LABEL: file_names[{{ *}}1]{{.*}} "bar.c"
+; DWWL-LABEL: file_names[ 1]:
+; DWWL-NEXT: name: "bar.c"
 ; DWWL:        2 0 1 0 0 is_stmt prologue_end
 ; DWWL-NOT:                      prologue_end

test/MC/ARM/dwarf-asm-multiple-sections.s

@@ -55,7 +55,8 @@ b:
 // DWARF-DL: version: [[DWVER]]
 // DWARF-DL-5:    address_size: 4
 // DWARF-DL-5:    include_directories[  0] = ""
-// DWARF-DL:      file_names[  [[DWFILE]]] {{.*}} "<stdin>"
+// DWARF-DL:      file_names[  [[DWFILE]]]:
+// DWARF-DL:      name: "<stdin>"
 // DWARF-DL:      0x0000000000000000     17      0      1   0   0  is_stmt
 // DWARF-DL-NEXT: 0x0000000000000004     17      0      1   0   0  is_stmt end_sequence
 // DWARF-DL-NEXT: 0x0000000000000000     21      0      1   0   0  is_stmt

test/MC/ELF/debug-md5.s

@@ -13,9 +13,14 @@
 # CHECK: include_directories[ 1] = .debug_line_str[0x[[DIR1:[0-9a-f]+]]] = "dir1"
 # CHECK: include_directories[ 2] = .debug_line_str[0x[[DIR2:[0-9a-f]+]]] = "dir2"
 # CHECK-NOT: include_directories
-# CHECK: Dir MD5 Checksum File Name
+# CHECK: file_names[ 0]:
-# CHECK: file_names[ 0] 1 00112233445566778899aabbccddeeff .debug_line_str[0x[[FILE1:[0-9a-f]+]]] = "foo"
+# CHECK-NEXT: name: .debug_line_str[0x[[FILE1:[0-9a-f]+]]] = "foo"
-# CHECK: file_names[ 1] 2 ffeeddccbbaa99887766554433221100 .debug_line_str[0x[[FILE2:[0-9a-f]+]]] = "bar"
+# CHECK-NEXT: dir_index: 1
+# CHECK-NEXT: md5_checksum: 00112233445566778899aabbccddeeff
+# CHECK: file_names[ 1]:
+# CHECK-NEXT: name: .debug_line_str[0x[[FILE2:[0-9a-f]+]]] = "bar"
+# CHECK-NEXT: dir_index: 2
+# CHECK-NEXT: md5_checksum: ffeeddccbbaa99887766554433221100
 
 # CHECK: .debug_line_str contents:
 # CHECK-NEXT: 0x[[DIR0]]: ""

test/MC/MachO/gen-dwarf-cpp.s

@@ -16,11 +16,15 @@ L1:	leave
 // We check that the source name "t.s" is picked up
 // CHECK: include_directories[  1] = "{{.*(/|\\\\)}}test{{(/|\\\\)}}MC{{(/|\\\\)}}MachO"
 // CHECK: include_directories[  2] = "inc"
-// CHECK:                 Dir  Mod Time   File Len   File Name
+// CHECK: file_names[  1]:
-// CHECK:                 ---- ---------- ---------- ---------------------------
+// CHECK-NEXT: name: "gen-dwarf-cpp.s"
-// CHECK: file_names[  1]    1 0x00000000 0x00000000 "gen-dwarf-cpp.s"
+// CHECK-NEXT: dir_index: 1
-// CHECK: file_names[  2]    0 0x00000000 0x00000000 "t.s"
+// CHECK: file_names[  2]:
-// CHECK: file_names[  3]    2 0x00000000 0x00000000 "g.s"
+// CHECK-NEXT: name: "t.s"
+// CHECK-NEXT: dir_index: 0
+// CHECK: file_names[  3]:
+// CHECK-NEXT: name: "g.s"
+// CHECK-NEXT: dir_index: 2
 // CHECK-NOT: file_names
 
 // We check that the source line number 100 is picked up before the "movl"

test/MC/MachO/gen-dwarf-macro-cpp.s

@@ -11,7 +11,9 @@
 // rdar://12637628
 
 // We check that the source name "foo.S" is picked up
-// CHECK:                 Dir  Mod Time   File Len   File Name
+// CHECK: file_names[  1]:
-// CHECK:                 ---- ---------- ---------- ---------------------------
+// CHECK-NEXT: name: "gen-dwarf-macro-cpp.s"
-// CHECK: file_names[  1]    1 0x00000000 0x00000000 "gen-dwarf-macro-cpp.s"
+// CHECK-NEXT: dir_index: 1
-// CHECK: file_names[  2]    0 0x00000000 0x00000000 "foo.S"
+// CHECK: file_names[  2]:
+// CHECK-NEXT: name: "foo.S"
+// CHECK-NEXT: dir_index: 0

test/MC/MachO/gen-dwarf.s

@@ -109,9 +109,9 @@ _x:	.long 1
 // CHECK: standard_opcode_lengths[DW_LNS_set_epilogue_begin] = 0
 // CHECK: standard_opcode_lengths[DW_LNS_set_isa] = 1
 // We don't check include_directories as it has a temp path
-// CHECK:                 Dir  Mod Time   File Len   File Name
+// CHECK: file_names[  1]:
-// CHECK:                 ---- ---------- ---------- ---------------------------
+// CHECK-NEXT: name: "gen-dwarf.s"
-// CHECK: file_names[  1]    1 0x00000000 0x00000000 "gen-dwarf.s"
+// CHECK-NEXT: dir_index: 1
 
 // CHECK: Address            Line   Column File   ISA Discriminator Flags
 // CHECK: ------------------ ------ ------ ------ --- ------------- -------------

test/tools/dsymutil/X86/basic-linking-x86.test

@@ -153,18 +153,18 @@ CHECK-NEXT:[0x0000000100000f40, 0x0000000100000f84)
 CHECK-NEXT:[0x0000000100000f90, 0x0000000100000fa9)
 
 CHECK: .debug_line contents:
-CHECK:                Dir  Mod Time   File Len   File Name
+CHECK: file_names[  1]:
-CHECK-NEXT:                 ---- ---------- ---------- ---------------------------
+CHECK-NEXT: name: "basic1.c"
-CHECK-NEXT: file_names[  1]    0 0x00000000 0x00000000 "basic1.c"
+CHECK-NEXT: dir_index: 0
 CHECK: Address            Line   Column File   ISA Discriminator Flags
 CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- -------------
 CHECK-NEXT: 0x0000000100000ea0     23      0      1   0             0  is_stmt
 CHECK-NEXT: 0x0000000100000eb6     24      0      1   0             0  is_stmt prologue_end
 CHECK-NEXT: 0x0000000100000ec4     24      0      1   0             0  is_stmt end_sequence
 
-CHECK:                 Dir  Mod Time   File Len   File Name
+CHECK: file_names[  1]:
-CHECK-NEXT:                 ---- ---------- ---------- ---------------------------
+CHECK-NEXT: name: "basic2.c"
-CHECK-NEXT: file_names[  1]    0 0x00000000 0x00000000 "basic2.c"
+CHECK-NEXT: dir_index: 0
 CHECK: Address            Line   Column File   ISA Discriminator Flags
 CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- -------------
 CHECK-NEXT: 0x0000000100000ed0     19      0      1   0             0  is_stmt
@@ -174,9 +174,9 @@ CHECK-NEXT: 0x0000000100000f20     14      0      1   0             0  is_stmt
 CHECK-NEXT: 0x0000000100000f24     15      0      1   0             0  is_stmt prologue_end
 CHECK-NEXT: 0x0000000100000f37     15      0      1   0             0  is_stmt end_sequence
 
-CHECK:                 Dir  Mod Time   File Len   File Name
+CHECK: file_names[  1]:
-CHECK-NEXT:                 ---- ---------- ---------- ---------------------------
+CHECK-NEXT: name: "basic3.c"
-CHECK-NEXT: file_names[  1]    0 0x00000000 0x00000000 "basic3.c"
+CHECK-NEXT: dir_index: 0
 CHECK: Address            Line   Column File   ISA Discriminator Flags
 CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- -------------
 CHECK-NEXT: 0x0000000100000f40     16      0      1   0             0  is_stmt

test/tools/dsymutil/X86/basic-lto-dw4-linking-x86.test

@@ -138,9 +138,9 @@ CHECK-NEXT: Address Range Header: length = 0x0000002c, version = 0x0002, cu_offs
 CHECK-NEXT: [0x0000000100000f90, 0x0000000100000fb4)
 
 CHECK: .debug_line contents:
-CHECK:                 Dir  Mod Time   File Len   File Name
+CHECK: file_names[  1]:
-CHECK-NEXT:                 ---- ---------- ---------- ---------------------------
+CHECK-NEXT: name: "basic1.c"
-CHECK-NEXT: file_names[  1]    0 0x00000000 0x00000000 "basic1.c"
+CHECK-NEXT: dir_index: 0
 CHECK: Address            Line   Column File   ISA Discriminator Flags
 CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- -------------
 CHECK-NEXT: 0x0000000100000f40     26      0      1   0             0  is_stmt
@@ -148,9 +148,9 @@ CHECK-NEXT: 0x0000000100000f44     27     10      1   0             0  is_stmt p
 CHECK-NEXT: 0x0000000100000f49     27      3      1   0             0
 CHECK-NEXT: 0x0000000100000f4b     27      3      1   0             0  end_sequence
 
-CHECK:                 Dir  Mod Time   File Len   File Name
+CHECK: file_names[  1]:
-CHECK-NEXT:                 ---- ---------- ---------- ---------------------------
+CHECK-NEXT: name: "basic2.c"
-CHECK-NEXT: file_names[  1]    0 0x00000000 0x00000000 "basic2.c"
+CHECK-NEXT: dir_index: 0
 CHECK: Address            Line   Column File   ISA Discriminator Flags
 CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- -------------
 CHECK-NEXT: 0x0000000100000f50     19      0      1   0             0  is_stmt
@@ -164,9 +164,9 @@ CHECK-NEXT: 0x0000000100000f83     20     31      1   0             0
 CHECK-NEXT: 0x0000000100000f85     20      3      1   0             0
 CHECK-NEXT: 0x0000000100000f87     20      3      1   0             0  end_sequence
 
-CHECK:                 Dir  Mod Time   File Len   File Name
+CHECK: file_names[  1]:
-CHECK-NEXT:                 ---- ---------- ---------- ---------------------------
+CHECK-NEXT: name: "basic3.c"
-CHECK-NEXT: file_names[  1]    0 0x00000000 0x00000000 "basic3.c"
+CHECK-NEXT: dir_index: 0
 CHECK: Address            Line   Column File   ISA Discriminator Flags
 CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- -------------
 CHECK-NEXT: 0x0000000100000f90     16      0      1   0             0  is_stmt

test/tools/dsymutil/X86/basic-lto-linking-x86.test

@@ -150,25 +150,25 @@ CHECK-NEXT: [0x0000000100000f90, 0x0000000100000fb4)
 
 
 CHECK: .debug_line contents
-CHECK:                 Dir  Mod Time   File Len   File Name
+CHECK: file_names[  1]:
-CHECK-NEXT:                 ---- ---------- ---------- ---------------------------
+CHECK-NEXT: name: "basic1.c"
-CHECK-NEXT: file_names[  1]    0 0x00000000 0x00000000 "basic1.c"
+CHECK-NEXT: dir_index: 0
 CHECK: 0x0000000100000f40     23      0      1   0             0  is_stmt
 CHECK: 0x0000000100000f44     24      0      1   0             0  is_stmt prologue_end
 CHECK: 0x0000000100000f4b     24      0      1   0             0  is_stmt end_sequence
 
-CHECK:                 Dir  Mod Time   File Len   File Name
+CHECK: file_names[  1]:
-CHECK-NEXT:                 ---- ---------- ---------- ---------------------------
+CHECK-NEXT: name: "basic2.c"
-CHECK-NEXT: file_names[  1]    0 0x00000000 0x00000000 "basic2.c"
+CHECK-NEXT: dir_index: 0
 CHECK: 0x0000000100000f50     19      0      1   0             0  is_stmt
 CHECK: 0x0000000100000f54     20      0      1   0             0  is_stmt prologue_end
 CHECK: 0x0000000100000f63     15      0      1   0             0  is_stmt
 CHECK: 0x0000000100000f72     20      0      1   0             0  is_stmt
 CHECK: 0x0000000100000f89     20      0      1   0             0  is_stmt end_sequence
 
-CHECK:                 Dir  Mod Time   File Len   File Name
+CHECK: file_names[  1]:
-CHECK-NEXT:                 ---- ---------- ---------- ---------------------------
+CHECK-NEXT: name: "basic3.c"
-CHECK-NEXT: file_names[  1]    0 0x00000000 0x00000000 "basic3.c"
+CHECK-NEXT: dir_index: 0
 CHECK: 0x0000000100000f90     16      0      1   0             0  is_stmt
 CHECK: 0x0000000100000f94     12      0      1   0             0  is_stmt prologue_end
 CHECK: 0x0000000100000f9a     17      0      1   0             0  is_stmt

tools/llvm-objdump/llvm-objdump.cpp

@@ -408,7 +408,7 @@ protected:
   std::unordered_map<std::string, std::vector<StringRef>> LineCache;
 
 private:
-  bool cacheSource(const std::string& File);
+  bool cacheSource(const DILineInfo& LineInfoFile);
 
 public:
   SourcePrinter() = default;
@@ -423,23 +423,29 @@ public:
                                StringRef Delimiter = "; ");
 };
 
-bool SourcePrinter::cacheSource(const std::string& File) {
+bool SourcePrinter::cacheSource(const DILineInfo &LineInfo) {
-  auto BufferOrError = MemoryBuffer::getFile(File);
+  std::unique_ptr<MemoryBuffer> Buffer;
-  if (!BufferOrError)
+  if (LineInfo.Source) {
-    return false;
+    Buffer = MemoryBuffer::getMemBuffer(*LineInfo.Source);
+  } else {
+    auto BufferOrError = MemoryBuffer::getFile(LineInfo.FileName);
+    if (!BufferOrError)
+      return false;
+    Buffer = std::move(*BufferOrError);
+  }
   // Chomp the file to get lines
-  size_t BufferSize = (*BufferOrError)->getBufferSize();
+  size_t BufferSize = Buffer->getBufferSize();
-  const char *BufferStart = (*BufferOrError)->getBufferStart();
+  const char *BufferStart = Buffer->getBufferStart();
   for (const char *Start = BufferStart, *End = BufferStart;
        End < BufferStart + BufferSize; End++)
     if (*End == '\n' || End == BufferStart + BufferSize - 1 ||
         (*End == '\r' && *(End + 1) == '\n')) {
-      LineCache[File].push_back(StringRef(Start, End - Start));
+      LineCache[LineInfo.FileName].push_back(StringRef(Start, End - Start));
       if (*End == '\r')
         End++;
       Start = End + 1;
     }
-  SourceCache[File] = std::move(*BufferOrError);
+  SourceCache[LineInfo.FileName] = std::move(Buffer);
   return true;
 }
 
@@ -463,7 +469,7 @@ void SourcePrinter::printSourceLine(raw_ostream &OS, uint64_t Address,
     OS << Delimiter << LineInfo.FileName << ":" << LineInfo.Line << "\n";
   if (PrintSource) {
     if (SourceCache.find(LineInfo.FileName) == SourceCache.end())
-      if (!cacheSource(LineInfo.FileName))
+      if (!cacheSource(LineInfo))
         return;
     auto FileBuffer = SourceCache.find(LineInfo.FileName);
     if (FileBuffer != SourceCache.end()) {

unittests/IR/MetadataTest.cpp

@@ -1450,19 +1450,24 @@ TEST_F(DIFileTest, get) {
   DIFile::ChecksumKind CSKind = DIFile::ChecksumKind::CSK_MD5;
   StringRef ChecksumString = "000102030405060708090a0b0c0d0e0f";
   DIFile::ChecksumInfo<StringRef> Checksum(CSKind, ChecksumString);
-  auto *N = DIFile::get(Context, Filename, Directory, Checksum);
+  StringRef Source = "source";
+  auto *N = DIFile::get(Context, Filename, Directory, Checksum, Source);
 
   EXPECT_EQ(dwarf::DW_TAG_file_type, N->getTag());
   EXPECT_EQ(Filename, N->getFilename());
   EXPECT_EQ(Directory, N->getDirectory());
   EXPECT_EQ(Checksum, N->getChecksum());
-  EXPECT_EQ(N, DIFile::get(Context, Filename, Directory, Checksum));
+  EXPECT_EQ(Source, N->getSource());
+  EXPECT_EQ(N, DIFile::get(Context, Filename, Directory, Checksum, Source));
 
-  EXPECT_NE(N, DIFile::get(Context, "other", Directory, Checksum));
+  EXPECT_NE(N, DIFile::get(Context, "other", Directory, Checksum, Source));
-  EXPECT_NE(N, DIFile::get(Context, Filename, "other", Checksum));
+  EXPECT_NE(N, DIFile::get(Context, Filename, "other", Checksum, Source));
   DIFile::ChecksumInfo<StringRef> OtherChecksum(DIFile::ChecksumKind::CSK_SHA1, ChecksumString);
   EXPECT_NE(
       N, DIFile::get(Context, Filename, Directory, OtherChecksum));
+  StringRef OtherSource = "other";
+  EXPECT_NE(N, DIFile::get(Context, Filename, Directory, Checksum, OtherSource));
+  EXPECT_NE(N, DIFile::get(Context, Filename, Directory, Checksum));
   EXPECT_NE(N, DIFile::get(Context, Filename, Directory));
 
   TempDIFile Temp = N->clone();