Frontend: Change PluginASTAction::ParseArgs to take a CompilerInstance object

for use in reporting diagnostics.
 - We don't want to use the Action's own CompilerInstance, because that is only
   initialized during file processing and I like that invariant.

Also, if ParseArgs returns false then abandon execution.

Also, remove unused PluginASTAction::PrintHelp virtual method.

llvm-svn: 110039

clang/examples/PrintFunctionNames/PrintFunctionNames.cpp

@@ -15,6 +15,7 @@
 #include "clang/Frontend/FrontendPluginRegistry.h"
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/AST.h"
+#include "clang/Frontend/CompilerInstance.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace clang;
 
@@ -37,9 +38,20 @@ protected:
     return new PrintFunctionsConsumer();
   }
 
-  bool ParseArgs(const std::vector<std::string>& args) {
-    for (unsigned i=0; i<args.size(); ++i)
+  bool ParseArgs(const CompilerInstance &CI,
+                 const std::vector<std::string>& args) {
+    for (unsigned i = 0, e = args.size(); i != e; ++i) {
       llvm::errs() << "PrintFunctionNames arg = " << args[i] << "\n";
+
+      // Example error handling.
+      if (args[i] == "-an-error") {
+        Diagnostic &D = CI.getDiagnostics();
+        unsigned DiagID = D.getCustomDiagID(
+          Diagnostic::Error, "invalid argument '" + args[i] + "'");
+        D.Report(DiagID);
+        return false;
+      }
+    }
     if (args.size() && args[0] == "help")
       PrintHelp(llvm::errs());
 

clang/include/clang/Frontend/FrontendAction.h

@@ -225,8 +225,14 @@ protected:
                                          llvm::StringRef InFile) = 0;
 
 public:
-  virtual bool ParseArgs(const std::vector<std::string>& arg) = 0;
-  virtual void PrintHelp(llvm::raw_ostream&) = 0;
+  /// ParseArgs - Parse the given plugin command line arguments.
+  ///
+  /// \param CI - The compiler instance, for use in reporting diagnostics.
+  /// \return True if the parsing succeeded; otherwise the plugin will be
+  /// destroyed and no action run. The plugin is responsible for using the
+  /// CompilerInstance's Diagnostic object to report errors.
+  virtual bool ParseArgs(const CompilerInstance &CI,
+                         const std::vector<std::string> &arg) = 0;
 };
 
 /// PreprocessorFrontendAction - Abstract base class to use for preprocessor

clang/tools/driver/cc1_main.cpp

@@ -83,14 +83,14 @@ static FrontendAction *CreateFrontendBaseAction(CompilerInstance &CI) {
   case ParseSyntaxOnly:        return new SyntaxOnlyAction();
 
   case PluginAction: {
-
     for (FrontendPluginRegistry::iterator it =
            FrontendPluginRegistry::begin(), ie = FrontendPluginRegistry::end();
          it != ie; ++it) {
       if (it->getName() == CI.getFrontendOpts().ActionName) {
-        PluginASTAction* plugin = it->instantiate();
-        plugin->ParseArgs(CI.getFrontendOpts().PluginArgs);
-        return plugin;
+        llvm::OwningPtr<PluginASTAction> P(it->instantiate());
+        if (!P->ParseArgs(CI, CI.getFrontendOpts().PluginArgs))
+          return 0;
+        return P.take();
       }
     }