[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, 33 insertions, 15 deletions

diff --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 8ede318e0e1..76eef5e3725 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/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) ||
-        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"))
+        parseIdentifier(Keyword))
       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();