[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, 4 insertions, 2 deletions

diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index ea995288b28..69c10f535e5 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/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