Revert "[ASTMatchers] Make isExpandedFromMacro accept llvm::StringRef… (llvm#167060)" (llvm#169238)

This reverts commit a52e1af.

That commit reverted a change (making isExpandedFromMacro take a
std::string) that was explicitly added to avoid lifetime issues. We ran
into issues with some internal matchers due to this, and it probably is
not an uncommon downstream use case. This patch restroes the original
functionality and adds a test to ensure that the functionality is
preserved.

https://reviews.llvm.org/D90303 contains more discussion.

Author: boomanaiden154

clang-tools-extra/clang-tidy/objc/AssertEqualsCheck.cpp

@@ -25,7 +25,7 @@ void AssertEqualsCheck::registerMatchers(MatchFinder *Finder) {
   for (const auto &[CurrName, _] : NameMap) {
     Finder->addMatcher(
         binaryOperator(anyOf(hasOperatorName("!="), hasOperatorName("==")),
-                       isExpandedFromMacro(CurrName),
+                       isExpandedFromMacro(std::string(CurrName)),
                        anyOf(hasLHS(hasType(qualType(
                                  hasCanonicalType(asString("NSString *"))))),
                              hasRHS(hasType(qualType(

clang/docs/LibASTMatchersReference.html

@@ -4222,7 +4222,7 @@ <h2 id="narrowing-matchers">Narrowing Matchers</h2>
 </pre></td></tr>
 
 
-<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;</td><td class="name" onclick="toggle('isExpandedFromMacro0')"><a name="isExpandedFromMacro0Anchor">isExpandedFromMacro</a></td><td>StringRef MacroName</td></tr>
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;</td><td class="name" onclick="toggle('isExpandedFromMacro0')"><a name="isExpandedFromMacro0Anchor">isExpandedFromMacro</a></td><td>std::string MacroName</td></tr>
 <tr><td colspan="4" class="doc" id="isExpandedFromMacro0"><pre>Matches statements that are (transitively) expanded from the named macro.
 Does not match if only part of the statement is expanded from that macro or
 if different parts of the statement are expanded from different
@@ -5643,7 +5643,7 @@ <h2 id="narrowing-matchers">Narrowing Matchers</h2>
 </pre></td></tr>
 
 
-<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('isExpandedFromMacro1')"><a name="isExpandedFromMacro1Anchor">isExpandedFromMacro</a></td><td>StringRef MacroName</td></tr>
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('isExpandedFromMacro1')"><a name="isExpandedFromMacro1Anchor">isExpandedFromMacro</a></td><td>std::string MacroName</td></tr>
 <tr><td colspan="4" class="doc" id="isExpandedFromMacro1"><pre>Matches statements that are (transitively) expanded from the named macro.
 Does not match if only part of the statement is expanded from that macro or
 if different parts of the statement are expanded from different
@@ -5843,7 +5843,7 @@ <h2 id="narrowing-matchers">Narrowing Matchers</h2>
 </pre></td></tr>
 
 
-<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1TypeLoc.html">TypeLoc</a>&gt;</td><td class="name" onclick="toggle('isExpandedFromMacro2')"><a name="isExpandedFromMacro2Anchor">isExpandedFromMacro</a></td><td>StringRef MacroName</td></tr>
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1TypeLoc.html">TypeLoc</a>&gt;</td><td class="name" onclick="toggle('isExpandedFromMacro2')"><a name="isExpandedFromMacro2Anchor">isExpandedFromMacro</a></td><td>std::string MacroName</td></tr>
 <tr><td colspan="4" class="doc" id="isExpandedFromMacro2"><pre>Matches statements that are (transitively) expanded from the named macro.
 Does not match if only part of the statement is expanded from that macro or
 if different parts of the statement are expanded from different

clang/include/clang/ASTMatchers/ASTMatchers.h

@@ -330,7 +330,7 @@ AST_POLYMORPHIC_MATCHER_REGEX(isExpansionInFileMatching,
 /// appearances of the macro.
 AST_POLYMORPHIC_MATCHER_P(isExpandedFromMacro,
                           AST_POLYMORPHIC_SUPPORTED_TYPES(Decl, Stmt, TypeLoc),
-                          StringRef, MacroName) {
+                          std::string, MacroName) {
   // Verifies that the statement' beginning and ending are both expanded from
   // the same instance of the given macro.
   auto& Context = Finder->getASTContext();

clang/unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp

@@ -26,6 +26,19 @@ TEST_P(ASTMatchersTest, IsExpandedFromMacro_MatchesInFile) {
   EXPECT_TRUE(matches(input, binaryOperator(isExpandedFromMacro("MY_MACRO"))));
 }
 
+static std::string constructMacroName(llvm::StringRef A, llvm::StringRef B) {
+  return (A + "_" + B).str();
+}
+
+TEST_P(ASTMatchersTest, IsExpandedFromMacro_ConstructedMacroName) {
+  StringRef input = R"cc(
+#define MY_MACRO(a) (4 + (a))
+    void Test() { MY_MACRO(4); }
+  )cc";
+  auto matcher = isExpandedFromMacro(constructMacroName("MY", "MACRO"));
+  EXPECT_TRUE(matches(input, binaryOperator(matcher)));
+}
+
 TEST_P(ASTMatchersTest, IsExpandedFromMacro_MatchesNested) {
   StringRef input = R"cc(
 #define MY_MACRO(a) (4 + (a))