[PATCH 1/2] [Driver] Make Driver::DefaultTargetTriple private (NFCI)

[vsk]

Summary

The clang driver knows about two kinds of target triples: default and
effective. Default triples are needed to get ToolChains. ToolChains can
then be used to determine more specific effective triples.

Inconsistent use of two different kinds of target triples leads to
inconsistent error reporting and wasted computation (n.b that effective
triples are not cached).

Ideally, default triples would only be used as a means of getting
effective triples. Make Driver::DefaultTargetTriple private in the hopes
of discouraging further use of default triples.

[dexonsmith]

If no one is using it, making it private is obvious goodness. LGTM.

cfe/trunk/include/clang/Driver/Driver.h

public:
   std::string SysRoot;
 
   /// Dynamic loader prefix, if present
   std::string DyldPrefix;
 
   /// If the standard library is used
   bool UseStdLib;
 
-  /// Default target triple.
-  std::string DefaultTargetTriple;
-
   /// Driver title to use with help.
   std::string DriverTitle;
 
   /// Information about the host which can be overridden by the user.
   std::string HostBits, HostMachine, HostSystem, HostRelease;
 
   /// The file to log CC_PRINT_OPTIONS output to, if enabled.
   const char *CCPrintOptionsFilename;
public:
   /// to CCLogDiagnosticsFilename or to stderr, in a stable machine readable
   /// format.
   unsigned CCLogDiagnostics : 1;
 
   /// Whether the driver is generating diagnostics for debugging purposes.
   unsigned CCGenDiagnostics : 1;
 
 private:
+  /// Default target triple.
+  std::string DefaultTargetTriple;
+
   /// Name to use when invoking gcc/g++.
   std::string CCCGenericGCCName;
 
   /// Whether to check that input files exist when constructing compilation
   /// jobs.
   unsigned CheckInputsExist : 1;
 
 public:

cfe/trunk/lib/Driver/Driver.cpp

 
 Driver::Driver(StringRef ClangExecutable, StringRef DefaultTargetTriple,
                DiagnosticsEngine &Diags,
                IntrusiveRefCntPtr<vfs::FileSystem> VFS)
     : Opts(createDriverOptTable()), Diags(Diags), VFS(std::move(VFS)),
       Mode(GCCMode), SaveTemps(SaveTempsNone), BitcodeEmbed(EmbedNone),
       LTOMode(LTOK_None), ClangExecutable(ClangExecutable),
       SysRoot(DEFAULT_SYSROOT), UseStdLib(true),
-      DefaultTargetTriple(DefaultTargetTriple),
       DriverTitle("clang LLVM compiler"), CCPrintOptionsFilename(nullptr),
       CCPrintHeadersFilename(nullptr), CCLogDiagnosticsFilename(nullptr),
       CCCPrintBindings(false), CCPrintHeaders(false), CCLogDiagnostics(false),
-      CCGenDiagnostics(false), CCCGenericGCCName(""), CheckInputsExist(true),
-      CCCUsePCH(true), SuppressMissingInputWarning(false) {
+      CCGenDiagnostics(false), DefaultTargetTriple(DefaultTargetTriple),
+      CCCGenericGCCName(""), CheckInputsExist(true), CCCUsePCH(true),
+      SuppressMissingInputWarning(false) {
 
   // Provide a sane fallback if no VFS is specified.
   if (!this->VFS)
     this->VFS = vfs::getRealFileSystem();
 
   Name = llvm::sys::path::filename(ClangExecutable);
   Dir = llvm::sys::path::parent_path(ClangExecutable);
   InstalledDir = Dir; // Provide a sensible default installed dir.