From 9c1af474b8bb2b86e0596f34453c711d2c185ffe Mon Sep 17 00:00:00 2001
From: Ilya Biryukov <ibiryukov@google.com>
Date: Wed, 19 Jun 2019 13:56:36 +0000
Subject: [PATCH] [Syntax] Fix a crash when dumping empty token buffer

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@363801 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Tooling/Syntax/Tokens.cpp           | 6 +++---
 unittests/Tooling/Syntax/TokensTest.cpp | 8 ++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/lib/Tooling/Syntax/Tokens.cpp b/lib/Tooling/Syntax/Tokens.cpp
index e22623741c..b4ecb85248 100644
--- a/lib/Tooling/Syntax/Tokens.cpp
+++ b/lib/Tooling/Syntax/Tokens.cpp
@@ -477,8 +477,7 @@ std::string TokenBuffer::dumpForTests() const {
 
   auto DumpTokens = [this, &PrintToken](llvm::raw_ostream &OS,
                                         llvm::ArrayRef<syntax::Token> Tokens) {
-    if (Tokens.size() == 1) {
-      assert(Tokens[0].kind() == tok::eof);
+    if (Tokens.empty()) {
       OS << "<empty>";
       return;
     }
@@ -495,7 +494,8 @@ std::string TokenBuffer::dumpForTests() const {
 
   OS << "expanded tokens:\n"
      << "  ";
-  DumpTokens(OS, ExpandedTokens);
+  // (!) we do not show '<eof>'.
+  DumpTokens(OS, llvm::makeArrayRef(ExpandedTokens).drop_back());
   OS << "\n";
 
   std::vector<FileID> Keys;
diff --git a/unittests/Tooling/Syntax/TokensTest.cpp b/unittests/Tooling/Syntax/TokensTest.cpp
index 34c80fce2a..a812b844c8 100644
--- a/unittests/Tooling/Syntax/TokensTest.cpp
+++ b/unittests/Tooling/Syntax/TokensTest.cpp
@@ -290,6 +290,14 @@ file './input.cpp'
     # pragma GCC visibility push ( public ) # pragma GCC visibility pop
   mappings:
     ['#'_0, '<eof>'_13) => ['<eof>'_0, '<eof>'_0)
+)"},
+      // Empty files should not crash.
+      {R"cpp()cpp", R"(expanded tokens:
+  <empty>
+file './input.cpp'
+  spelled tokens:
+    <empty>
+  no mappings.
 )"}};
   for (auto &Test : TestCases)
     EXPECT_EQ(collectAndDump(Test.first), Test.second)
-- 
2.40.0