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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@359035 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/PlistSupport.h b/include/clang/Basic/PlistSupport.h
index f81b469bb87da83e7341a77a5de92faba717a1d9..557462a5b90d01234ad4846e300b62d1bb167639 100644 (file)
--- a/include/clang/Basic/PlistSupport.h
+++ b/include/clang/Basic/PlistSupport.h
@@ -127,7 +127,11 @@ inline void EmitRange(raw_ostream &o, const SourceManager &SM,
   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";
 }
 

diff --git a/include/clang/Lex/Lexer.h b/include/clang/Lex/Lexer.h
index 4a8a0f6f0d67952e8765b014b4ccc22782981f40..69cfe62e4bdbc32100bc513c440b6f6b067b989d 100644 (file)
--- a/include/clang/Lex/Lexer.h
+++ b/include/clang/Lex/Lexer.h
@@ -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,

diff --git a/unittests/Lex/LexerTest.cpp b/unittests/Lex/LexerTest.cpp
index 320b60ea639acd3dca94d94699f582192df49a13..7b14f56201eb0613d5700b7ab5b841878fe8fcdf 100644 (file)
--- a/unittests/Lex/LexerTest.cpp
+++ b/unittests/Lex/LexerTest.cpp
@@ -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