Vendor import of llvm release_31 branch r155985:

http://llvm.org/svn/llvm-project/llvm/branches/release_31@155985

12 files changed, 199 insertions, 314 deletions

diff --git a/lib/Support/CMakeLists.txt b/lib/Support/CMakeLists.txt
index 9b3b6c8..9103327 100644
--- a/lib/Support/CMakeLists.txt
+++ b/lib/Support/CMakeLists.txt
@@ -32,7 +32,7 @@ add_llvm_library(LLVMSupport
   IntrusiveRefCntPtr.cpp
   IsInf.cpp
   IsNAN.cpp
-  JSONParser.cpp
+  Locale.cpp
   LockFileManager.cpp
   ManagedStatic.cpp
   MemoryBuffer.cpp
diff --git a/lib/Support/JSONParser.cpp b/lib/Support/JSONParser.cpp
deleted file mode 100644
index 5dfcf29..0000000
--- a/lib/Support/JSONParser.cpp
+++ /dev/null
@@ -1,302 +0,0 @@
-//===--- JSONParser.cpp - Simple JSON parser ------------------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-//  This file implements a JSON parser.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Support/JSONParser.h"
-
-#include "llvm/ADT/Twine.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/MemoryBuffer.h"
-
-using namespace llvm;
-
-JSONParser::JSONParser(StringRef Input, SourceMgr *SM)
-  : SM(SM), Failed(false) {
-  InputBuffer = MemoryBuffer::getMemBuffer(Input, "JSON");
-  SM->AddNewSourceBuffer(InputBuffer, SMLoc());
-  End = InputBuffer->getBuffer().end();
-  Position = InputBuffer->getBuffer().begin();
-}
-
-JSONValue *JSONParser::parseRoot() {
-  if (Position != InputBuffer->getBuffer().begin())
-    report_fatal_error("Cannot reuse JSONParser.");
-  if (isWhitespace())
-    nextNonWhitespace();
-  if (errorIfAtEndOfFile("'[' or '{' at start of JSON text"))
-    return 0;
-  switch (*Position) {
-    case '[':
-      return new (ValueAllocator.Allocate<JSONArray>(1)) JSONArray(this);
-    case '{':
-      return new (ValueAllocator.Allocate<JSONObject>(1)) JSONObject(this);
-    default:
-      setExpectedError("'[' or '{' at start of JSON text", *Position);
-      return 0;
-  }
-}
-
-bool JSONParser::validate() {
-  JSONValue *Root = parseRoot();
-  if (Root == NULL) {
-    return false;
-  }
-  return skip(*Root);
-}
-
-bool JSONParser::skip(const JSONAtom &Atom) {
-  switch(Atom.getKind()) {
-    case JSONAtom::JK_Array:
-    case JSONAtom::JK_Object:
-      return skipContainer(*cast<JSONContainer>(&Atom));
-    case JSONAtom::JK_String:
-      return true;
-    case JSONAtom::JK_KeyValuePair:
-      return skip(*cast<JSONKeyValuePair>(&Atom)->Value);
-  }
-  llvm_unreachable("Impossible enum value.");
-}
-
-// Sets the current error to:
-// "expected <Expected>, but found <Found>".
-void JSONParser::setExpectedError(StringRef Expected, StringRef Found) {
-  SM->PrintMessage(SMLoc::getFromPointer(Position), SourceMgr::DK_Error,
-    "expected " + Expected + ", but found " + Found + ".", ArrayRef<SMRange>());
-  Failed = true;
-}
-
-// Sets the current error to:
-// "expected <Expected>, but found <Found>".
-void JSONParser::setExpectedError(StringRef Expected, char Found) {
-  setExpectedError(Expected, ("'" + StringRef(&Found, 1) + "'").str());
-}
-
-// If there is no character available, returns true and sets the current error
-// to: "expected <Expected>, but found EOF.".
-bool JSONParser::errorIfAtEndOfFile(StringRef Expected) {
-  if (Position == End) {
-    setExpectedError(Expected, "EOF");
-    return true;
-  }
-  return false;
-}
-
-// Sets the current error if the current character is not C to:
-// "expected 'C', but got <current character>".
-bool JSONParser::errorIfNotAt(char C, StringRef Message) {
-  if (*Position != C) {
-    std::string Expected =
-      ("'" + StringRef(&C, 1) + "' " + Message).str();
-    if (Position == End)
-      setExpectedError(Expected, "EOF");
-    else
-      setExpectedError(Expected, *Position);
-    return true;
-  }
-  return false;
-}
-
-// Forbidding inlining improves performance by roughly 20%.
-// FIXME: Remove once llvm optimizes this to the faster version without hints.
-LLVM_ATTRIBUTE_NOINLINE static bool
-wasEscaped(StringRef::iterator First, StringRef::iterator Position);
-
-// Returns whether a character at 'Position' was escaped with a leading '\'.
-// 'First' specifies the position of the first character in the string.
-static bool wasEscaped(StringRef::iterator First,
-                       StringRef::iterator Position) {
-  assert(Position - 1 >= First);
-  StringRef::iterator I = Position - 1;
-  // We calulate the number of consecutive '\'s before the current position
-  // by iterating backwards through our string.
-  while (I >= First && *I == '\\') --I;
-  // (Position - 1 - I) now contains the number of '\'s before the current
-  // position. If it is odd, the character at 'Positon' was escaped.
-  return (Position - 1 - I) % 2 == 1;
-}
-
-// Parses a JSONString, assuming that the current position is on a quote.
-JSONString *JSONParser::parseString() {
-  assert(Position != End);
-  assert(!isWhitespace());
-  if (errorIfNotAt('"', "at start of string"))
-    return 0;
-  StringRef::iterator First = Position + 1;
-
-  // Benchmarking shows that this loop is the hot path of the application with
-  // about 2/3rd of the runtime cycles. Since escaped quotes are not the common
-  // case, and multiple escaped backslashes before escaped quotes are very rare,
-  // we pessimize this case to achieve a smaller inner loop in the common case.
-  // We're doing that by having a quick inner loop that just scans for the next
-  // quote. Once we find the quote we check the last character to see whether
-  // the quote might have been escaped. If the last character is not a '\', we
-  // know the quote was not escaped and have thus found the end of the string.
-  // If the immediately preceding character was a '\', we have to scan backwards
-  // to see whether the previous character was actually an escaped backslash, or
-  // an escape character for the quote. If we find that the current quote was
-  // escaped, we continue parsing for the next quote and repeat.
-  // This optimization brings around 30% performance improvements.
-  do {
-    // Step over the current quote.
-    ++Position;
-    // Find the next quote.
-    while (Position != End && *Position != '"')
-      ++Position;
-    if (errorIfAtEndOfFile("'\"' at end of string"))
-      return 0;
-    // Repeat until the previous character was not a '\' or was an escaped
-    // backslash.
-  } while (*(Position - 1) == '\\' && wasEscaped(First, Position));
-
-  return new (ValueAllocator.Allocate<JSONString>())
-      JSONString(StringRef(First, Position - First));
-}
-
-
-// Advances the position to the next non-whitespace position.
-void JSONParser::nextNonWhitespace() {
-  do {
-    ++Position;
-  } while (isWhitespace());
-}
-
-// Checks if there is a whitespace character at the current position.
-bool JSONParser::isWhitespace() {
-  return *Position == ' ' || *Position == '\t' ||
-         *Position == '\n' || *Position == '\r';
-}
-
-bool JSONParser::failed() const {
-  return Failed;
-}
-
-// Parses a JSONValue, assuming that the current position is at the first
-// character of the value.
-JSONValue *JSONParser::parseValue() {
-  assert(Position != End);
-  assert(!isWhitespace());
-  switch (*Position) {
-    case '[':
-      return new (ValueAllocator.Allocate<JSONArray>(1)) JSONArray(this);
-    case '{':
-      return new (ValueAllocator.Allocate<JSONObject>(1)) JSONObject(this);
-    case '"':
-      return parseString();
-    default:
-      setExpectedError("'[', '{' or '\"' at start of value", *Position);
-      return 0;
-  }
-}
-
-// Parses a JSONKeyValuePair, assuming that the current position is at the first
-// character of the key, value pair.
-JSONKeyValuePair *JSONParser::parseKeyValuePair() {
-  assert(Position != End);
-  assert(!isWhitespace());
-
-  JSONString *Key = parseString();
-  if (Key == 0)
-    return 0;
-
-  nextNonWhitespace();
-  if (errorIfNotAt(':', "between key and value"))
-    return 0;
-
-  nextNonWhitespace();
-  const JSONValue *Value = parseValue();
-  if (Value == 0)
-    return 0;
-
-  return new (ValueAllocator.Allocate<JSONKeyValuePair>(1))
-    JSONKeyValuePair(Key, Value);
-}
-
-/// \brief Parses the first element of a JSON array or object, or closes the
-/// array.
-///
-/// The method assumes that the current position is before the first character
-/// of the element, with possible white space in between. When successful, it
-/// returns the new position after parsing the element. Otherwise, if there is
-/// no next value, it returns a default constructed StringRef::iterator.
-StringRef::iterator JSONParser::parseFirstElement(JSONAtom::Kind ContainerKind,
-                                                  char StartChar, char EndChar,
-                                                  const JSONAtom *&Element) {
-  assert(*Position == StartChar);
-  Element = 0;
-  nextNonWhitespace();
-  if (errorIfAtEndOfFile("value or end of container at start of container"))
-    return StringRef::iterator();
-
-  if (*Position == EndChar)
-    return StringRef::iterator();
-
-  Element = parseElement(ContainerKind);
-  if (Element == 0)
-    return StringRef::iterator();
-
-  return Position;
-}
-
-/// \brief Parses the next element of a JSON array or object, or closes the
-/// array.
-///
-/// The method assumes that the current position is before the ',' which
-/// separates the next element from the current element. When successful, it
-/// returns the new position after parsing the element. Otherwise, if there is
-/// no next value, it returns a default constructed StringRef::iterator.
-StringRef::iterator JSONParser::parseNextElement(JSONAtom::Kind ContainerKind,
-                                                 char EndChar,
-                                                 const JSONAtom *&Element) {
-  Element = 0;
-  nextNonWhitespace();
-  if (errorIfAtEndOfFile("',' or end of container for next element"))
-    return 0;
-
-  if (*Position == ',') {
-    nextNonWhitespace();
-    if (errorIfAtEndOfFile("element in container"))
-      return StringRef::iterator();
-
-    Element = parseElement(ContainerKind);
-    if (Element == 0)
-      return StringRef::iterator();
-
-    return Position;
-  } else if (*Position == EndChar) {
-      return StringRef::iterator();
-  } else {
-    setExpectedError("',' or end of container for next element", *Position);
-    return StringRef::iterator();
-  }
-}
-
-const JSONAtom *JSONParser::parseElement(JSONAtom::Kind ContainerKind) {
-  switch (ContainerKind) {
-    case JSONAtom::JK_Array:
-      return parseValue();
-    case JSONAtom::JK_Object:
-      return parseKeyValuePair();
-    default:
-      llvm_unreachable("Impossible code path");
-  }
-}
-
-bool JSONParser::skipContainer(const JSONContainer &Container) {
-  for (JSONContainer::AtomIterator I = Container.atom_current(),
-                                   E = Container.atom_end();
-       I != E; ++I) {
-    assert(*I != 0);
-    if (!skip(**I))
-      return false;
-  }
-  return !failed();
-}
diff --git a/lib/Support/Locale.cpp b/lib/Support/Locale.cpp
new file mode 100644
index 0000000..17b9b6c
--- /dev/null
+++ b/lib/Support/Locale.cpp
@@ -0,0 +1,10 @@
+#include "llvm/Support/Locale.h"
+#include "llvm/Config/config.h"
+
+#ifdef __APPLE__
+#include "LocaleXlocale.inc"
+#elif LLVM_ON_WIN32
+#include "LocaleWindows.inc"
+#else
+#include "LocaleGeneric.inc"
+#endif
diff --git a/lib/Support/LocaleGeneric.inc b/lib/Support/LocaleGeneric.inc
new file mode 100644
index 0000000..278deee
--- /dev/null
+++ b/lib/Support/LocaleGeneric.inc
@@ -0,0 +1,17 @@
+#include <cwctype>
+
+namespace llvm {
+namespace sys {
+namespace locale {
+
+int columnWidth(StringRef s) {
+    return s.size();
+}
+
+bool isPrint(int c) {
+    return iswprint(c);
+}
+
+}
+}
+}
diff --git a/lib/Support/LocaleWindows.inc b/lib/Support/LocaleWindows.inc
new file mode 100644
index 0000000..6827ac1
--- /dev/null
+++ b/lib/Support/LocaleWindows.inc
@@ -0,0 +1,15 @@
+namespace llvm {
+namespace sys {
+namespace locale {
+
+int columnWidth(StringRef s) {
+    return s.size();
+}
+
+bool isPrint(int c) {
+    return ' ' <= c && c <= '~';
+}
+
+}
+}
+}
\ No newline at end of file
diff --git a/lib/Support/LocaleXlocale.inc b/lib/Support/LocaleXlocale.inc
new file mode 100644
index 0000000..f595e7c
--- /dev/null
+++ b/lib/Support/LocaleXlocale.inc
@@ -0,0 +1,61 @@
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/ManagedStatic.h"
+#include <cassert>
+#include <xlocale.h>
+
+
+namespace {
+  struct locale_holder {
+    locale_holder()
+    : l(newlocale(LC_CTYPE_MASK,"en_US.UTF-8",LC_GLOBAL_LOCALE))
+    {
+      assert(NULL!=l);
+    }
+    ~locale_holder() {
+      freelocale(l);
+    }
+
+    int mbswidth(llvm::SmallString<16> s) const {
+       // this implementation assumes no '\0' in s
+      assert(s.size()==strlen(s.c_str()));
+
+      size_t size = mbstowcs_l(NULL,s.c_str(),0,l);
+      assert(size!=(size_t)-1);
+      if (size==0)
+        return 0;
+      llvm::SmallVector<wchar_t,200> ws(size);
+      size = mbstowcs_l(&ws[0],s.c_str(),ws.size(),l);
+      assert(ws.size()==size);
+      return wcswidth_l(&ws[0],ws.size(),l);
+    }
+
+    int isprint(int c) const {
+      return iswprint_l(c,l);
+    }
+
+  private:
+
+    locale_t l;
+  };
+
+  llvm::ManagedStatic<locale_holder> l;
+}
+
+namespace llvm {
+namespace sys {
+namespace locale {
+
+int columnWidth(StringRef s) {
+  int width = l->mbswidth(s);
+  assert(width>=0);
+  return width;
+}
+
+bool isPrint(int c) {
+  return l->isprint(c);
+}
+
+}
+}
+}
diff --git a/lib/Support/SmallPtrSet.cpp b/lib/Support/SmallPtrSet.cpp
index 68d9c29..3b53e9f 100644
--- a/lib/Support/SmallPtrSet.cpp
+++ b/lib/Support/SmallPtrSet.cpp
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/Support/MathExtras.h"
 #include <algorithm>
 #include <cstdlib>
@@ -102,7 +103,7 @@ bool SmallPtrSetImpl::erase_imp(const void * Ptr) {
 }
 
 const void * const *SmallPtrSetImpl::FindBucketFor(const void *Ptr) const {
-  unsigned Bucket = Hash(Ptr);
+  unsigned Bucket = DenseMapInfo<void *>::getHashValue(Ptr) & (CurArraySize-1);
   unsigned ArraySize = CurArraySize;
   unsigned ProbeAmt = 1;
   const void *const *Array = CurArray;
diff --git a/lib/Support/SourceMgr.cpp b/lib/Support/SourceMgr.cpp
index bbe36b2..15278c5 100644
--- a/lib/Support/SourceMgr.cpp
+++ b/lib/Support/SourceMgr.cpp
@@ -193,7 +193,8 @@ SMDiagnostic SourceMgr::GetMessage(SMLoc Loc, SourceMgr::DiagKind Kind,
 }
 
 void SourceMgr::PrintMessage(SMLoc Loc, SourceMgr::DiagKind Kind,
-                             const Twine &Msg, ArrayRef<SMRange> Ranges) const {
+                             const Twine &Msg, ArrayRef<SMRange> Ranges,
+                             bool ShowColors) const {
   SMDiagnostic Diagnostic = GetMessage(Loc, Kind, Msg, Ranges);
   
   // Report the message with the diagnostic handler if present.
@@ -208,7 +209,7 @@ void SourceMgr::PrintMessage(SMLoc Loc, SourceMgr::DiagKind Kind,
   assert(CurBuf != -1 && "Invalid or unspecified location!");
   PrintIncludeStack(getBufferInfo(CurBuf).IncludeLoc, OS);
 
-  Diagnostic.print(0, OS);
+  Diagnostic.print(0, OS, ShowColors);
 }
 
 //===----------------------------------------------------------------------===//
@@ -225,7 +226,14 @@ SMDiagnostic::SMDiagnostic(const SourceMgr &sm, SMLoc L, const std::string &FN,
 }
 
 
-void SMDiagnostic::print(const char *ProgName, raw_ostream &S) const {
+void SMDiagnostic::print(const char *ProgName, raw_ostream &S,
+                         bool ShowColors) const {
+  // Display colors only if OS goes to a tty.
+  ShowColors &= S.is_displayed();
+
+  if (ShowColors)
+    S.changeColor(raw_ostream::SAVEDCOLOR, true);
+
   if (ProgName && ProgName[0])
     S << ProgName << ": ";
 
@@ -244,13 +252,33 @@ void SMDiagnostic::print(const char *ProgName, raw_ostream &S) const {
   }
 
   switch (Kind) {
-  case SourceMgr::DK_Error: S << "error: "; break;
-  case SourceMgr::DK_Warning: S << "warning: "; break;
-  case SourceMgr::DK_Note: S << "note: "; break;
+  case SourceMgr::DK_Error:
+    if (ShowColors)
+      S.changeColor(raw_ostream::RED, true);
+    S << "error: ";
+    break;
+  case SourceMgr::DK_Warning:
+    if (ShowColors)
+      S.changeColor(raw_ostream::MAGENTA, true);
+    S << "warning: ";
+    break;
+  case SourceMgr::DK_Note:
+    if (ShowColors)
+      S.changeColor(raw_ostream::BLACK, true);
+    S << "note: ";
+    break;
   }
-  
+
+  if (ShowColors) {
+    S.resetColor();
+    S.changeColor(raw_ostream::SAVEDCOLOR, true);
+  }
+
   S << Message << '\n';
 
+  if (ShowColors)
+    S.resetColor();
+
   if (LineNo == -1 || ColumnNo == -1)
     return;
 
@@ -292,6 +320,9 @@ void SMDiagnostic::print(const char *ProgName, raw_ostream &S) const {
   }
   S << '\n';
 
+  if (ShowColors)
+    S.changeColor(raw_ostream::GREEN, true);
+
   // Print out the caret line, matching tabs in the source line.
   for (unsigned i = 0, e = CaretLine.size(), OutCol = 0; i != e; ++i) {
     if (i >= LineContents.size() || LineContents[i] != '\t') {
@@ -306,6 +337,9 @@ void SMDiagnostic::print(const char *ProgName, raw_ostream &S) const {
       ++OutCol;
     } while (OutCol & 7);
   }
+
+  if (ShowColors)
+    S.resetColor();
   
   S << '\n';
 }
diff --git a/lib/Support/Unix/Process.inc b/lib/Support/Unix/Process.inc
index 2d7fd38..f640462 100644
--- a/lib/Support/Unix/Process.inc
+++ b/lib/Support/Unix/Process.inc
@@ -290,6 +290,10 @@ const char *Process::OutputBold(bool bg) {
   return "\033[1m";
 }
 
+const char *Process::OutputReverse() {
+  return "\033[7m";
+}
+
 const char *Process::ResetColor() {
   return "\033[0m";
 }
diff --git a/lib/Support/Windows/Process.inc b/lib/Support/Windows/Process.inc
index 913b073..9a388b4 100644
--- a/lib/Support/Windows/Process.inc
+++ b/lib/Support/Windows/Process.inc
@@ -215,6 +215,38 @@ const char *Process::OutputColor(char code, bool bold, bool bg) {
   return 0;
 }
 
+static WORD GetConsoleTextAttribute(HANDLE hConsoleOutput) {
+  CONSOLE_SCREEN_BUFFER_INFO info;
+  GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &info);
+  return info.wAttributes;
+}
+
+const char *Process::OutputReverse() {
+  const WORD attributes
+   = GetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE));
+
+  const WORD foreground_mask = FOREGROUND_BLUE | FOREGROUND_GREEN |
+    FOREGROUND_RED | FOREGROUND_INTENSITY;
+  const WORD background_mask = BACKGROUND_BLUE | BACKGROUND_GREEN |
+    BACKGROUND_RED | BACKGROUND_INTENSITY;
+  const WORD color_mask = foreground_mask | background_mask;
+
+  WORD new_attributes =
+    ((attributes & FOREGROUND_BLUE     )?BACKGROUND_BLUE     :0) |
+    ((attributes & FOREGROUND_GREEN    )?BACKGROUND_GREEN    :0) |
+    ((attributes & FOREGROUND_RED      )?BACKGROUND_RED      :0) |
+    ((attributes & FOREGROUND_INTENSITY)?BACKGROUND_INTENSITY:0) |
+    ((attributes & BACKGROUND_BLUE     )?FOREGROUND_BLUE     :0) |
+    ((attributes & BACKGROUND_GREEN    )?FOREGROUND_GREEN    :0) |
+    ((attributes & BACKGROUND_RED      )?FOREGROUND_RED      :0) |
+    ((attributes & BACKGROUND_INTENSITY)?FOREGROUND_INTENSITY:0) |
+    0;
+  new_attributes = (attributes & ~color_mask) | (new_attributes & color_mask);
+
+  SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), new_attributes);
+  return 0;
+}
+
 const char *Process::ResetColor() {
   SetConsoleTextAttribute(GetStdHandle(STD_OUTPUT_HANDLE), defaultColors());
   return 0;
diff --git a/lib/Support/YAMLParser.cpp b/lib/Support/YAMLParser.cpp
index 330519f..d38b51b 100644
--- a/lib/Support/YAMLParser.cpp
+++ b/lib/Support/YAMLParser.cpp
@@ -1732,7 +1732,7 @@ StringRef ScalarNode::unescapeDoubleQuoted( StringRef UnquotedValue
           if (UnquotedValue.size() < 3)
             // TODO: Report error.
             break;
-          unsigned int UnicodeScalarValue;
+          unsigned int UnicodeScalarValue = 0;
           UnquotedValue.substr(1, 2).getAsInteger(16, UnicodeScalarValue);
           encodeUTF8(UnicodeScalarValue, Storage);
           UnquotedValue = UnquotedValue.substr(2);
@@ -1742,7 +1742,7 @@ StringRef ScalarNode::unescapeDoubleQuoted( StringRef UnquotedValue
           if (UnquotedValue.size() < 5)
             // TODO: Report error.
             break;
-          unsigned int UnicodeScalarValue;
+          unsigned int UnicodeScalarValue = 0;
           UnquotedValue.substr(1, 4).getAsInteger(16, UnicodeScalarValue);
           encodeUTF8(UnicodeScalarValue, Storage);
           UnquotedValue = UnquotedValue.substr(4);
@@ -1752,7 +1752,7 @@ StringRef ScalarNode::unescapeDoubleQuoted( StringRef UnquotedValue
           if (UnquotedValue.size() < 9)
             // TODO: Report error.
             break;
-          unsigned int UnicodeScalarValue;
+          unsigned int UnicodeScalarValue = 0;
           UnquotedValue.substr(1, 8).getAsInteger(16, UnicodeScalarValue);
           encodeUTF8(UnicodeScalarValue, Storage);
           UnquotedValue = UnquotedValue.substr(8);
diff --git a/lib/Support/raw_ostream.cpp b/lib/Support/raw_ostream.cpp
index 72d3986..86cdca1 100644
--- a/lib/Support/raw_ostream.cpp
+++ b/lib/Support/raw_ostream.cpp
@@ -633,6 +633,19 @@ raw_ostream &raw_fd_ostream::resetColor() {
   return *this;
 }
 
+raw_ostream &raw_fd_ostream::reverseColor() {
+  if (sys::Process::ColorNeedsFlush())
+    flush();
+  const char *colorcode = sys::Process::OutputReverse();
+  if (colorcode) {
+    size_t len = strlen(colorcode);
+    write(colorcode, len);
+    // don't account colors towards output characters
+    pos -= len;
+  }
+  return *this;
+}
+
 bool raw_fd_ostream::is_displayed() const {
   return sys::Process::FileDescriptorIsDisplayed(FD);
 }