diff --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
--- a/clang/include/clang/Lex/Preprocessor.h
+++ b/clang/include/clang/Lex/Preprocessor.h
@@ -1722,6 +1722,9 @@
   /// Lex the next token for this preprocessor.
   void Lex(Token &Result);
 
+  /// Lex all tokens for this preprocessor until (and excluding) end of file.
+  void LexTokensUntilEOF(std::vector<Token> *Tokens = nullptr);
+
   /// Lex a token, forming a header-name token if possible.
   bool LexHeaderName(Token &Result, bool AllowMacroExpansion = true);
 
diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -998,6 +998,17 @@
   }
 }
 
+void Preprocessor::LexTokensUntilEOF(std::vector<Token> *Tokens) {
+  while (1) {
+    Token Tok;
+    Lex(Tok);
+    if (Tok.isOneOf(tok::unknown, tok::eof, tok::eod))
+      break;
+    if (Tokens != nullptr)
+      Tokens->push_back(Tok);
+  }
+}
+
 /// Lex a header-name token (including one formed from header-name-tokens if
 /// \p AllowConcatenation is \c true).
 ///
diff --git a/clang/unittests/Analysis/MacroExpansionContextTest.cpp b/clang/unittests/Analysis/MacroExpansionContextTest.cpp
--- a/clang/unittests/Analysis/MacroExpansionContextTest.cpp
+++ b/clang/unittests/Analysis/MacroExpansionContextTest.cpp
@@ -73,12 +73,7 @@
     // Lex source text.
     PP.EnterMainSourceFile();
 
-    while (true) {
-      Token Tok;
-      PP.Lex(Tok);
-      if (Tok.is(tok::eof))
-        break;
-    }
+    PP.LexTokensUntilEOF();
 
     // Callbacks have been executed at this point.
     return Ctx;
diff --git a/clang/unittests/Basic/SourceManagerTest.cpp b/clang/unittests/Basic/SourceManagerTest.cpp
--- a/clang/unittests/Basic/SourceManagerTest.cpp
+++ b/clang/unittests/Basic/SourceManagerTest.cpp
@@ -138,13 +138,7 @@
   PP.EnterMainSourceFile();
 
   std::vector<Token> toks;
-  while (1) {
-    Token tok;
-    PP.Lex(tok);
-    if (tok.is(tok::eof))
-      break;
-    toks.push_back(tok);
-  }
+  PP.LexTokensUntilEOF(&toks);
 
   // Make sure we got the tokens that we expected.
   ASSERT_EQ(3U, toks.size());
@@ -195,13 +189,7 @@
   llvm::SmallString<8> Scratch;
 
   std::vector<Token> toks;
-  while (1) {
-    Token tok;
-    PP.Lex(tok);
-    if (tok.is(tok::eof))
-      break;
-    toks.push_back(tok);
-  }
+  PP.LexTokensUntilEOF(&toks);
 
   // Make sure we got the tokens that we expected.
   ASSERT_EQ(4U, toks.size()) << "a >> b c";
@@ -452,13 +440,7 @@
   PP.EnterMainSourceFile();
 
   std::vector<Token> toks;
-  while (1) {
-    Token tok;
-    PP.Lex(tok);
-    if (tok.is(tok::eof))
-      break;
-    toks.push_back(tok);
-  }
+  PP.LexTokensUntilEOF(&toks);
 
   // Make sure we got the tokens that we expected.
   ASSERT_EQ(4U, toks.size());
@@ -574,13 +556,7 @@
   PP.EnterMainSourceFile();
 
   std::vector<Token> toks;
-  while (1) {
-    Token tok;
-    PP.Lex(tok);
-    if (tok.is(tok::eof))
-      break;
-    toks.push_back(tok);
-  }
+  PP.LexTokensUntilEOF(&toks);
 
   // Make sure we got the tokens that we expected.
   ASSERT_EQ(0U, toks.size());
diff --git a/clang/unittests/Lex/LexerTest.cpp b/clang/unittests/Lex/LexerTest.cpp
--- a/clang/unittests/Lex/LexerTest.cpp
+++ b/clang/unittests/Lex/LexerTest.cpp
@@ -74,13 +74,7 @@
     PP = CreatePP(Source, ModLoader);
 
     std::vector<Token> toks;
-    while (1) {
-      Token tok;
-      PP->Lex(tok);
-      if (tok.is(tok::eof))
-        break;
-      toks.push_back(tok);
-    }
+    PP->LexTokensUntilEOF(&toks);
 
     return toks;
   }
@@ -628,12 +622,7 @@
 TEST_F(LexerTest, CreatedFIDCountForPredefinedBuffer) {
   TrivialModuleLoader ModLoader;
   auto PP = CreatePP("", ModLoader);
-  while (1) {
-    Token tok;
-    PP->Lex(tok);
-    if (tok.is(tok::eof))
-      break;
-  }
+  PP->LexTokensUntilEOF();
   EXPECT_EQ(SourceMgr.getNumCreatedFIDsForFileID(PP->getPredefinesFileID()),
             1U);
 }
diff --git a/clang/unittests/Lex/ModuleDeclStateTest.cpp b/clang/unittests/Lex/ModuleDeclStateTest.cpp
--- a/clang/unittests/Lex/ModuleDeclStateTest.cpp
+++ b/clang/unittests/Lex/ModuleDeclStateTest.cpp
@@ -90,12 +90,7 @@
     PP.addPPCallbacks(std::move(C));
     PP.EnterMainSourceFile();
 
-    while (1) {
-      Token tok;
-      PP.Lex(tok);
-      if (tok.is(tok::eof))
-        break;
-    }
+    PP.LexTokensUntilEOF();
   }
 
   FileSystemOptions FileMgrOpts;
diff --git a/clang/unittests/Lex/PPCallbacksTest.cpp b/clang/unittests/Lex/PPCallbacksTest.cpp
--- a/clang/unittests/Lex/PPCallbacksTest.cpp
+++ b/clang/unittests/Lex/PPCallbacksTest.cpp
@@ -229,13 +229,7 @@
 
     // Lex source text.
     PP.EnterMainSourceFile();
-
-    while (true) {
-      Token Tok;
-      PP.Lex(Tok);
-      if (Tok.is(tok::eof))
-        break;
-    }
+    PP.LexTokensUntilEOF();
 
     // Callbacks have been executed at this point -- return filename range.
     return Callbacks;
@@ -259,13 +253,7 @@
 
     // Lex source text.
     PP.EnterMainSourceFile();
-
-    while (true) {
-      Token Tok;
-      PP.Lex(Tok);
-      if (Tok.is(tok::eof))
-        break;
-    }
+    PP.LexTokensUntilEOF();
 
     return Callbacks->Results;
   }
@@ -290,12 +278,7 @@
 
     // Lex source text.
     PP.EnterMainSourceFile();
-    while (true) {
-      Token Tok;
-      PP.Lex(Tok);
-      if (Tok.is(tok::eof))
-        break;
-    }
+    PP.LexTokensUntilEOF();
 
     return Callbacks->Marks;
   }
@@ -334,12 +317,7 @@
 
     // Lex source text.
     PP.EnterMainSourceFile();
-    while (true) {
-      Token Tok;
-      PP.Lex(Tok);
-      if (Tok.is(tok::eof))
-        break;
-    }
+    PP.LexTokensUntilEOF();
 
     PragmaOpenCLExtensionCallbacks::CallbackParameters RetVal = {
       Callbacks->Name,
@@ -477,12 +455,7 @@
 
   // Lex source text.
   PP.EnterMainSourceFile();
-  while (true) {
-    Token Tok;
-    PP.Lex(Tok);
-    if (Tok.is(tok::eof))
-      break;
-  }
+  PP.LexTokensUntilEOF();
 
   ASSERT_EQ(1u, Callbacks->NumCalls);
   ASSERT_EQ(0u, DiagConsumer->getNumErrors());
diff --git a/clang/unittests/Lex/PPConditionalDirectiveRecordTest.cpp b/clang/unittests/Lex/PPConditionalDirectiveRecordTest.cpp
--- a/clang/unittests/Lex/PPConditionalDirectiveRecordTest.cpp
+++ b/clang/unittests/Lex/PPConditionalDirectiveRecordTest.cpp
@@ -87,13 +87,7 @@
   PP.EnterMainSourceFile();
 
   std::vector<Token> toks;
-  while (1) {
-    Token tok;
-    PP.Lex(tok);
-    if (tok.is(tok::eof))
-      break;
-    toks.push_back(tok);
-  }
+  PP.LexTokensUntilEOF(&toks);
 
   // Make sure we got the tokens that we expected.
   ASSERT_EQ(10U, toks.size());
diff --git a/clang/unittests/Lex/PPDependencyDirectivesTest.cpp b/clang/unittests/Lex/PPDependencyDirectivesTest.cpp
--- a/clang/unittests/Lex/PPDependencyDirectivesTest.cpp
+++ b/clang/unittests/Lex/PPDependencyDirectivesTest.cpp
@@ -133,12 +133,7 @@
   SmallVector<StringRef> IncludedFiles;
   PP.addPPCallbacks(std::make_unique<IncludeCollector>(PP, IncludedFiles));
   PP.EnterMainSourceFile();
-  while (true) {
-    Token tok;
-    PP.Lex(tok);
-    if (tok.is(tok::eof))
-      break;
-  }
+  PP.LexTokensUntilEOF();
 
   SmallVector<std::string> IncludedFilesSlash;
   for (StringRef IncludedFile : IncludedFiles)
diff --git a/clang/unittests/Lex/PPMemoryAllocationsTest.cpp b/clang/unittests/Lex/PPMemoryAllocationsTest.cpp
--- a/clang/unittests/Lex/PPMemoryAllocationsTest.cpp
+++ b/clang/unittests/Lex/PPMemoryAllocationsTest.cpp
@@ -75,12 +75,7 @@
   PP.Initialize(*Target);
   PP.EnterMainSourceFile();
 
-  while (1) {
-    Token tok;
-    PP.Lex(tok);
-    if (tok.is(tok::eof))
-      break;
-  }
+  PP.LexTokensUntilEOF();
 
   size_t NumAllocated = PP.getPreprocessorAllocator().getBytesAllocated();
   float BytesPerDefine = float(NumAllocated) / float(NumMacros);