r359035 - Re-apply r357823 "[Lexer] NFC: Fix an off-by-one bug in getAsCharRange()."

[Artem Dergachev via cfe-commits]

Author: dergachev
Date: Tue Apr 23 14:15:26 2019
New Revision: 359035

URL: http://llvm.org/viewvc/llvm-project?rev=359035&view=rev
Log:
Re-apply r357823 "[Lexer] NFC: Fix an off-by-one bug in getAsCharRange()."

It now comes with a follow-up fix for the clients of this API
in clangd and clang-tidy.

Differential Revision: https://reviews.llvm.org/D59977

Modified:
    cfe/trunk/include/clang/Basic/PlistSupport.h
    cfe/trunk/include/clang/Lex/Lexer.h
    cfe/trunk/unittests/Lex/LexerTest.cpp

Modified: cfe/trunk/include/clang/Basic/PlistSupport.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/PlistSupport.h?rev=359035&r1=359034&r2=359035&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/PlistSupport.h (original)
+++ cfe/trunk/include/clang/Basic/PlistSupport.h Tue Apr 23 14:15:26 2019
@@ -127,7 +127,11 @@ inline void EmitRange(raw_ostream &o, co
   assert(R.isCharRange() && "cannot handle a token range");
   Indent(o, indent) << "<array>\n";
   EmitLocation(o, SM, R.getBegin(), FM, indent + 1);
-  EmitLocation(o, SM, R.getEnd(), FM, indent + 1);
+
+  // The ".getLocWithOffset(-1)" emulates the behavior of an off-by-one bug
+  // in Lexer that is already fixed. It is here for backwards compatibility
+  // even though it is incorrect.
+  EmitLocation(o, SM, R.getEnd().getLocWithOffset(-1), FM, indent + 1);
   Indent(o, indent) << "</array>\n";
 }
 

Modified: cfe/trunk/include/clang/Lex/Lexer.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Lex/Lexer.h?rev=359035&r1=359034&r2=359035&view=diff
==============================================================================
--- cfe/trunk/include/clang/Lex/Lexer.h (original)
+++ cfe/trunk/include/clang/Lex/Lexer.h Tue Apr 23 14:15:26 2019
@@ -382,7 +382,7 @@ public:
     SourceLocation End = getLocForEndOfToken(Range.getEnd(), 0, SM, LangOpts);
     return End.isInvalid() ? CharSourceRange()
                            : CharSourceRange::getCharRange(
-                                 Range.getBegin(), End.getLocWithOffset(-1));
+                                 Range.getBegin(), End);
   }
   static CharSourceRange getAsCharRange(CharSourceRange Range,
                                         const SourceManager &SM,

Modified: cfe/trunk/unittests/Lex/LexerTest.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/Lex/LexerTest.cpp?rev=359035&r1=359034&r2=359035&view=diff
==============================================================================
--- cfe/trunk/unittests/Lex/LexerTest.cpp (original)
+++ cfe/trunk/unittests/Lex/LexerTest.cpp Tue Apr 23 14:15:26 2019
@@ -513,4 +513,23 @@ TEST_F(LexerTest, StringizingRasString)
   EXPECT_EQ(String6, R"(a\\\n\n\n    \\\\b)");
 }
 
+TEST_F(LexerTest, CharRangeOffByOne) {
+  std::vector<Token> toks = Lex(R"(#define MOO 1
+    void foo() { MOO; })");
+  const Token &moo = toks[5];
+
+  EXPECT_EQ(getSourceText(moo, moo), "MOO");
+
+  SourceRange R{moo.getLocation(), moo.getLocation()};
+
+  EXPECT_TRUE(
+      Lexer::isAtStartOfMacroExpansion(R.getBegin(), SourceMgr, LangOpts));
+  EXPECT_TRUE(
+      Lexer::isAtEndOfMacroExpansion(R.getEnd(), SourceMgr, LangOpts));
+
+  CharSourceRange CR = Lexer::getAsCharRange(R, SourceMgr, LangOpts);
+
+  EXPECT_EQ(Lexer::getSourceText(CR, SourceMgr, LangOpts), "MOO"); // Was "MO".
+}
+
 } // anonymous namespace