[Support] Promote cl::StringSaver to a separate utility

This class is generally useful.

In breaking it out, the primary change is that it has been made
non-virtual. It seems like being abstract led to there being 3 different
(2 in llvm + 1 in clang) concrete implementations which disagreed about
the ownership of the saved strings (see the manual call to free() in the
unittest StrDupSaver; yes this is different from the CommandLine.cpp
StrDupSaver which owns the stored strings; which is different from
Clang's StringSetSaver which just holds a reference to a
std::set<std::string> which owns the strings).

I've identified 2 other places in the
codebase that are open-coding this pattern:

  memcpy(Alloc.Allocate<char>(strlen(S)+1), S, strlen(S)+1)

I'll be switching them over. They are
* llvm::sys::Process::GetArgumentVector
* The StringAllocator member of YAMLIO's Input class
This also will allow simplifying Clang's driver.cpp quite a bit.

Let me know if there are any other places that could benefit from
StringSaver. I'm also thinking of adding a saveStringRef member for
getting a stable StringRef.

llvm-svn: 215784

1 files changed, 1 insertions, 9 deletions

diff --git a/llvm/include/llvm/Support/CommandLine.h b/llvm/include/llvm/Support/CommandLine.h
index fdd901200fe..ac25c59b904 100644
--- a/llvm/include/llvm/Support/CommandLine.h
+++ b/llvm/include/llvm/Support/CommandLine.h
@@ -24,6 +24,7 @@
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/StringSaver.h"
 #include <cassert>
 #include <climits>
 #include <cstdarg>
@@ -1772,15 +1773,6 @@ void getRegisteredOptions(StringMap<Option*> &Map);
 // Standalone command line processing utilities.
 //
 
-/// \brief Saves strings in the inheritor's stable storage and returns a stable
-/// raw character pointer.
-class StringSaver {
-  virtual void anchor();
-public:
-  virtual const char *SaveString(const char *Str) = 0;
-  virtual ~StringSaver() {};  // Pacify -Wnon-virtual-dtor.
-};
-
 /// \brief Tokenizes a command line that can contain escapes and quotes.
 //
 /// The quoting rules match those used by GCC and other tools that use