[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

1 files changed, 70 insertions, 28 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
index 8986af26c03..56e7af24af5 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ b/llvm/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,
-                   FileEntry.DirIdx);
-      if (HasMD5)
-        OS << FileEntry.Checksum.digest();
-      else
-        OS << format("0x%8.8" PRIx64 " 0x%8.8" PRIx64, FileEntry.ModTime,
-                     FileEntry.Length);
-      OS << ' ';
+      OS <<   format("file_names[%3u]:\n", I + FileBase);
+      OS <<          "           name: ";
       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,
-                   uint64_t EndPrologueOffset, bool *HasMD5) {
+parseV5EntryFormat(const DWARFDataExtractor &DebugLineData, uint32_t
+    *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)
-      *HasMD5 = true;
+    if (ContentTypes)
+      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 DWARFUnit *U, bool &HasMD5,
+                     const DWARFFormParams &FormParams, const DWARFContext
+                     &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,
-                              FileNames)) {
+                              FormParams, Ctx, U, ContentTypes,
+                              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;
 }