Make llvm::StringRef to std::string conversions explicit.

This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.

3 files changed, 5 insertions, 4 deletions

diff --git a/clang/unittests/Frontend/ASTUnitTest.cpp b/clang/unittests/Frontend/ASTUnitTest.cpp
index 5cb2087..fbc641e 100644
--- a/clang/unittests/Frontend/ASTUnitTest.cpp
+++ b/clang/unittests/Frontend/ASTUnitTest.cpp
@@ -87,7 +87,7 @@ TEST_F(ASTUnitTest, SaveLoadPreservesLangOptionsInPrintingPolicy) {
   EXPECT_TRUE(llvm::sys::fs::exists(ASTFileName));
 
   std::unique_ptr<ASTUnit> AU = ASTUnit::LoadFromASTFile(
-      ASTFileName.str(), PCHContainerOps->getRawReader(),
+      std::string(ASTFileName.str()), PCHContainerOps->getRawReader(),
       ASTUnit::LoadEverything, Diags, FileSystemOptions(),
       /*UseDebugInfo=*/false);
 
diff --git a/clang/unittests/Frontend/CompilerInstanceTest.cpp b/clang/unittests/Frontend/CompilerInstanceTest.cpp
index d2377d0..eeae2e9 100644
--- a/clang/unittests/Frontend/CompilerInstanceTest.cpp
+++ b/clang/unittests/Frontend/CompilerInstanceTest.cpp
@@ -32,8 +32,8 @@ TEST(CompilerInstance, DefaultVFSOverlayFromInvocation) {
 
   // Mount the VFS file itself on the path 'virtual.file'. Makes this test
   // a bit shorter than creating a new dummy file just for this purpose.
-  const std::string CurrentPathStr = CurrentPath.str();
-  const std::string FileNameStr = FileName.str();
+  const std::string CurrentPathStr = std::string(CurrentPath.str());
+  const std::string FileNameStr = std::string(FileName.str());
   const char *VFSYaml = "{ 'version': 0, 'roots': [\n"
                         "  { 'name': '%s',\n"
                         "    'type': 'directory',\n"
diff --git a/clang/unittests/Frontend/FrontendActionTest.cpp b/clang/unittests/Frontend/FrontendActionTest.cpp
index d0a3020..9f8a746 100644
--- a/clang/unittests/Frontend/FrontendActionTest.cpp
+++ b/clang/unittests/Frontend/FrontendActionTest.cpp
@@ -272,7 +272,8 @@ TEST(GeneratePCHFrontendAction, CacheGeneratedPCH) {
         MemoryBuffer::getMemBuffer("int foo(void) { return 1; }\n").release());
     Invocation->getFrontendOpts().Inputs.push_back(
         FrontendInputFile("test.h", Language::C));
-    Invocation->getFrontendOpts().OutputFile = StringRef(PCHFilename);
+    Invocation->getFrontendOpts().OutputFile =
+        std::string(StringRef(PCHFilename));
     Invocation->getFrontendOpts().ProgramAction = frontend::GeneratePCH;
     Invocation->getTargetOpts().Triple = "x86_64-apple-darwin19.0.0";
     CompilerInstance Compiler;