Index: lib/Support/SourceMgr.cpp
===================================================================
--- lib/Support/SourceMgr.cpp
+++ lib/Support/SourceMgr.cpp
@@ -19,6 +19,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Twine.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/Locale.h"
 #include "llvm/Support/MemoryBuffer.h"
@@ -35,6 +36,40 @@
 
 using namespace llvm;
 
+enum DiagnosticsFormats { Clang, MSVC, Vi };
+
+enum MsvcVersions {
+  MSVC40 = 1000,
+  MSVC97 = 1100,
+  MSVC60 = 1200,
+  MSVC2002 = 1300,
+  MSVC2003 = 1310,
+  MSVC2005 = 1400,
+  MSVC2008 = 1500,
+  MSVC2010 = 1600,
+  MSVC2012 = 1700,
+  MSVC2013 = 1800,
+  MSVC2015 = 1900,
+  MSVC2017 = 1910
+};
+
+static cl::opt<std::string> DiagnosticsFormatOpt(
+    "diagnostics-format",
+    cl::desc(
+        "Change diagnostic formatting to match IDE and command line tools"),
+    cl::init("clang"), cl::Hidden);
+
+static cl::opt<std::string>
+    MsvcVersionOpt("ms-compatibility-version",
+                   cl::desc("Specify Microsoft Visual Studio compatibility "
+                            "version for diagnostics formatting"),
+                   cl::init("19.00"), cl::Hidden);
+
+static cl::opt<bool> ShowColumnOpt(
+    "show-column",
+    cl::desc("Enable or disable showing column number for diagnostics message"),
+    cl::init(true), cl::Hidden);
+
 static const size_t TabStop = 8;
 
 unsigned SourceMgr::AddIncludeFile(const std::string &Filename,
@@ -365,8 +400,62 @@
   return c & 0x80;
 }
 
+// Convert a std::string to upper case
+static void toUp(std::string &S) {
+  for (size_t i = 0; i < S.length(); ++i) {
+    S[i] = ::toupper(S[i]);
+  }
+}
+
+// Convert string to integer value.
+static unsigned toInt(const std::string &S) {
+  if (S.empty())
+    return 0;
+  for (size_t i = 0; i < S.length(); ++i) {
+    if (!::isdigit(S[i]))
+      return -1;
+  }
+  return ::atoi(S.c_str());
+}
+
+// Parse MSVC version option string, convert it to integer value.
+static unsigned parseMsvcVersionOption() {
+  static unsigned MsvcVersion = UINT_MAX;
+  unsigned Major = 0, Minor = 0;
+  if (MsvcVersion != UINT_MAX)
+    return MsvcVersion;
+  size_t Pos = MsvcVersionOpt.find('.');
+  if (Pos != std::string::npos) {
+    Major = toInt(MsvcVersionOpt.substr(0, Pos));
+    Minor = toInt(MsvcVersionOpt.substr(Pos + 1));
+  } else
+    Major = toInt(MsvcVersionOpt);
+  MsvcVersion = (Major * 100) + Minor;
+  return MsvcVersion;
+}
+
+// Parse diagnostics format option string, convert it to integer.
+static unsigned parseDiagnosticsFormatOption() {
+  static unsigned DiagsFormat = UINT_MAX;
+  if (DiagsFormat != UINT_MAX)
+    return DiagsFormat;
+  std::string DF(DiagnosticsFormatOpt);
+  toUp(DF);
+  if (DF == "CLANG")
+    DiagsFormat = DiagnosticsFormats::Clang;
+  else if (DF == "MSVC")
+    DiagsFormat = DiagnosticsFormats::MSVC;
+  else if (DF == "VI")
+    DiagsFormat = DiagnosticsFormats::Vi;
+  return DiagsFormat;
+}
+
 void SMDiagnostic::print(const char *ProgName, raw_ostream &S, bool ShowColors,
                          bool ShowKindLabel) const {
+
+  unsigned DiagnosticsFormat = parseDiagnosticsFormatOption();
+  unsigned MsvcVersion = parseMsvcVersionOption();
+
   // Display colors only if OS supports colors.
   ShowColors &= S.has_colors();
 
@@ -382,12 +471,55 @@
     else
       S << Filename;
 
-    if (LineNo != -1) {
-      S << ':' << LineNo;
-      if (ColumnNo != -1)
-        S << ':' << (ColumnNo+1);
+    if (DiagnosticsFormat > DiagnosticsFormats::Vi) {
+      if (LineNo != -1) {
+        S << ':' << LineNo;
+        if (ColumnNo != -1)
+          S << ':' << (ColumnNo + 1);
+      }
+    } else if (LineNo != -1) {
+      switch (DiagnosticsFormat) {
+      default:
+      case DiagnosticsFormats::Clang:
+        S << ':' << LineNo;
+        break;
+      case DiagnosticsFormats::MSVC:
+        S << '(' << LineNo;
+        break;
+      case DiagnosticsFormats::Vi:
+        S << " +" << LineNo;
+        break;
+      }
+      if (ShowColumnOpt && (ColumnNo != -1)) {
+        int ColumnNoOffs = 0;
+        if (DiagnosticsFormat == DiagnosticsFormats::MSVC) {
+          S << ',';
+          // Visual Studio 2010 or earlier expects column number to be off by
+          // one
+          if (MsvcVersion <= MsvcVersions::MSVC2010)
+            ColumnNoOffs = 1;
+        } else
+          S << ':';
+        S << ((ColumnNo + 1) - ColumnNoOffs);
+      }
+      switch (DiagnosticsFormat) {
+      default:
+      case DiagnosticsFormats::Clang:
+      case DiagnosticsFormats::Vi:
+        S << ": ";
+        break;
+      case DiagnosticsFormats::MSVC:
+        // MSVC2013 and before print 'file(4) : error'. MSVC2015 gets rid of the
+        // space and prints 'file(4): error'.
+        if (MsvcVersion < MsvcVersions::MSVC2015)
+          S << ") : ";
+        else
+          S << "): ";
+        break;
+      }
+    } else {
+      S << ": ";
     }
-    S << ": ";
   }
 
   if (ShowKindLabel) {