Index: cfe/trunk/lib/CodeGen/CGDebugInfo.h
===================================================================
--- cfe/trunk/lib/CodeGen/CGDebugInfo.h
+++ cfe/trunk/lib/CodeGen/CGDebugInfo.h
@@ -442,6 +442,10 @@
   /// Remap a given path with the current debug prefix map
   std::string remapDIPath(StringRef) const;
 
+  /// Compute the file checksum debug info for input file ID.
+  llvm::DIFile::ChecksumKind computeChecksum(FileID FID,
+                                             SmallString<32> &Checksum) const;
+
   /// Get the file debug info descriptor for the input location.
   llvm::DIFile *getOrCreateFile(SourceLocation Loc);
 
Index: cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
+++ cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
@@ -41,6 +41,7 @@
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/MD5.h"
 #include "llvm/Support/Path.h"
 using namespace clang;
 using namespace clang::CodeGen;
@@ -320,11 +321,36 @@
   return StringRef();
 }
 
+llvm::DIFile::ChecksumKind
+CGDebugInfo::computeChecksum(FileID FID, SmallString<32> &Checksum) const {
+  Checksum.clear();
+
+  if (!CGM.getCodeGenOpts().EmitCodeView)
+    return llvm::DIFile::CSK_None;
+
+  SourceManager &SM = CGM.getContext().getSourceManager();
+  bool Invalid;
+  llvm::MemoryBuffer *MemBuffer = SM.getBuffer(FID, &Invalid);
+  if (Invalid)
+    return llvm::DIFile::CSK_None;
+
+  llvm::MD5 Hash;
+  llvm::MD5::MD5Result Result;
+
+  Hash.update(MemBuffer->getBuffer());
+  Hash.final(Result);
+
+  Hash.stringifyResult(Result, Checksum);
+  return llvm::DIFile::CSK_MD5;
+}
+
 llvm::DIFile *CGDebugInfo::getOrCreateFile(SourceLocation Loc) {
   if (!Loc.isValid())
     // If Location is not valid then use main input file.
     return DBuilder.createFile(remapDIPath(TheCU->getFilename()),
-                               remapDIPath(TheCU->getDirectory()));
+                               remapDIPath(TheCU->getDirectory()),
+                               TheCU->getFile()->getChecksumKind(),
+                               TheCU->getFile()->getChecksum());
 
   SourceManager &SM = CGM.getContext().getSourceManager();
   PresumedLoc PLoc = SM.getPresumedLoc(Loc);
@@ -332,7 +358,9 @@
   if (PLoc.isInvalid() || StringRef(PLoc.getFilename()).empty())
     // If the location is not valid then use main input file.
     return DBuilder.createFile(remapDIPath(TheCU->getFilename()),
-                               remapDIPath(TheCU->getDirectory()));
+                               remapDIPath(TheCU->getDirectory()),
+                               TheCU->getFile()->getChecksumKind(),
+                               TheCU->getFile()->getChecksum());
 
   // Cache the results.
   const char *fname = PLoc.getFilename();
@@ -344,8 +372,13 @@
       return cast<llvm::DIFile>(V);
   }
 
+  SmallString<32> Checksum;
+  llvm::DIFile::ChecksumKind CSKind =
+      computeChecksum(SM.getFileID(Loc), Checksum);
+
   llvm::DIFile *F = DBuilder.createFile(remapDIPath(PLoc.getFilename()),
-                                        remapDIPath(getCurrentDirname()));
+                                        remapDIPath(getCurrentDirname()),
+                                        CSKind, Checksum);
 
   DIFileCache[fname].reset(F);
   return F;
@@ -353,7 +386,9 @@
 
 llvm::DIFile *CGDebugInfo::getOrCreateMainFile() {
   return DBuilder.createFile(remapDIPath(TheCU->getFilename()),
-                             remapDIPath(TheCU->getDirectory()));
+                             remapDIPath(TheCU->getDirectory()),
+                             TheCU->getFile()->getChecksumKind(),
+                             TheCU->getFile()->getChecksum());
 }
 
 std::string CGDebugInfo::remapDIPath(StringRef Path) const {
@@ -396,6 +431,8 @@
 }
 
 void CGDebugInfo::CreateCompileUnit() {
+  SmallString<32> Checksum;
+  llvm::DIFile::ChecksumKind CSKind = llvm::DIFile::CSK_None;
 
   // Should we be asking the SourceManager for the main file name, instead of
   // accepting it as an argument? This just causes the main file name to
@@ -422,6 +459,7 @@
       llvm::sys::path::append(MainFileDirSS, MainFileName);
       MainFileName = MainFileDirSS.str();
     }
+    CSKind = computeChecksum(SM.getMainFileID(), Checksum);
   }
 
   llvm::dwarf::SourceLanguage LangTag;
@@ -467,7 +505,8 @@
   // FIXME - Eliminate TheCU.
   TheCU = DBuilder.createCompileUnit(
       LangTag, DBuilder.createFile(remapDIPath(MainFileName),
-                                    remapDIPath(getCurrentDirname())),
+                                   remapDIPath(getCurrentDirname()), CSKind,
+                                   Checksum),
       Producer, LO.Optimize, CGM.getCodeGenOpts().DwarfDebugFlags, RuntimeVers,
       CGM.getCodeGenOpts().SplitDwarfFile, EmissionKind, 0 /* DWOid */,
       CGM.getCodeGenOpts().SplitDwarfInlining);
Index: cfe/trunk/test/CodeGen/Inputs/debug-info-file-checksum.c
===================================================================
--- cfe/trunk/test/CodeGen/Inputs/debug-info-file-checksum.c
+++ cfe/trunk/test/CodeGen/Inputs/debug-info-file-checksum.c
@@ -0,0 +1,3 @@
+int foo(int x) {
+  return x+1;
+}
Index: cfe/trunk/test/CodeGen/debug-info-file-checksum.c
===================================================================
--- cfe/trunk/test/CodeGen/debug-info-file-checksum.c
+++ cfe/trunk/test/CodeGen/debug-info-file-checksum.c
@@ -0,0 +1,5 @@
+// RUN: %clang -emit-llvm -S -g -gcodeview -x c %S/Inputs/debug-info-file-checksum.c -o - | FileCheck %s
+
+// Check that "checksum" is created correctly for the compiled file.
+
+// CHECK: !DIFile(filename:{{.*}}, directory:{{.*}}, checksumkind: CSK_MD5, checksum: "a3b7d27af071accdeccaa933fc603608")