<rdar://problem/13509689> Introduce -module-file-info option that provides information about a particular module file.

This option can be useful for end users who want to know why they
ended up with a ton of different variants of the "std" module in their
module cache. This problem should go away over time, as we reduce the
need for module variants, but it will never go away entirely.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178148 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 132 insertions, 2 deletions

diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 2d945b5b04..0fb8e58b3d 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -644,6 +644,8 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       Opts.ProgramAction = frontend::InitOnly; break;
     case OPT_fsyntax_only:
       Opts.ProgramAction = frontend::ParseSyntaxOnly; break;
+    case OPT_module_file_info:
+      Opts.ProgramAction = frontend::ModuleFileInfo; break;
     case OPT_print_decl_contexts:
       Opts.ProgramAction = frontend::PrintDeclContext; break;
     case OPT_print_preamble:
@@ -779,7 +781,7 @@ static InputKind ParseFrontendArgs(FrontendOptions &Opts, ArgList &Args,
       .Case("objective-c-header", IK_ObjC)
       .Case("c++-header", IK_CXX)
       .Case("objective-c++-header", IK_ObjCXX)
-      .Case("ast", IK_AST)
+      .Cases("ast", "pcm", IK_AST)
       .Case("ir", IK_LLVM_IR)
       .Default(IK_None);
     if (DashX == IK_None)
@@ -1465,6 +1467,7 @@ static void ParsePreprocessorOutputArgs(PreprocessorOutputOptions &Opts,
   case frontend::GeneratePCH:
   case frontend::GeneratePTH:
   case frontend::ParseSyntaxOnly:
+  case frontend::ModuleFileInfo:
   case frontend::PluginAction:
   case frontend::PrintDeclContext:
   case frontend::RewriteObjC:
@@ -1627,6 +1630,8 @@ llvm::APInt ModuleSignature::getAsInteger() const {
 }
 
 std::string CompilerInvocation::getModuleHash() const {
+  // Note: For QoI reasons, the things we use as a hash here should all be
+  // dumped via the -module-info flag.
   using llvm::hash_code;
   using llvm::hash_value;
   using llvm::hash_combine;
diff --git a/lib/Frontend/FrontendActions.cpp b/lib/Frontend/FrontendActions.cpp
index f3466f0234..5c7567fa8c 100644
--- a/lib/Frontend/FrontendActions.cpp
+++ b/lib/Frontend/FrontendActions.cpp
@@ -19,6 +19,7 @@
 #include "clang/Lex/Pragma.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Parse/Parser.h"
+#include "clang/Serialization/ASTReader.h"
 #include "clang/Serialization/ASTWriter.h"
 #include "llvm/ADT/OwningPtr.h"
 #include "llvm/Support/FileSystem.h"
@@ -316,6 +317,130 @@ ASTConsumer *SyntaxOnlyAction::CreateASTConsumer(CompilerInstance &CI,
   return new ASTConsumer();
 }
 
+ASTConsumer *DumpModuleInfoAction::CreateASTConsumer(CompilerInstance &CI,
+                                                     StringRef InFile) {
+  return new ASTConsumer();
+}
+
+namespace {
+  /// \brief AST reader listener that dumps module information for a module
+  /// file.
+  class DumpModuleInfoListener : public ASTReaderListener {
+    llvm::raw_ostream &Out;
+
+  public:
+    DumpModuleInfoListener(llvm::raw_ostream &Out) : Out(Out) { }
+
+#define DUMP_BOOLEAN(Value, Text)                       \
+    Out.indent(4) << Text << ": " << (Value? "Yes" : "No") << "\n"
+
+    virtual bool ReadFullVersionInformation(StringRef FullVersion) {
+      Out.indent(2)
+        << "Generated by "
+        << (FullVersion == getClangFullRepositoryVersion()? "this"
+                                                          : "a different")
+        << " Clang: " << FullVersion << "\n";
+      return ASTReaderListener::ReadFullVersionInformation(FullVersion);
+    }
+
+    virtual bool ReadLanguageOptions(const LangOptions &LangOpts,
+                                     bool Complain) {
+      Out.indent(2) << "Language options:\n";
+#define LANGOPT(Name, Bits, Default, Description) \
+      DUMP_BOOLEAN(LangOpts.Name, Description);
+#define ENUM_LANGOPT(Name, Type, Bits, Default, Description) \
+      Out.indent(4) << Description << ": "                   \
+                    << static_cast<unsigned>(LangOpts.get##Name()) << "\n";
+#define VALUE_LANGOPT(Name, Bits, Default, Description) \
+      Out.indent(4) << Description << ": " << LangOpts.Name << "\n";
+#define BENIGN_LANGOPT(Name, Bits, Default, Description)
+#define BENIGN_ENUM_LANGOPT(Name, Type, Bits, Default, Description)
+#include "clang/Basic/LangOptions.def"
+      return false;
+    }
+
+    virtual bool ReadTargetOptions(const TargetOptions &TargetOpts,
+                                   bool Complain) {
+      Out.indent(2) << "Target options:\n";
+      Out.indent(4) << "  Triple: " << TargetOpts.Triple << "\n";
+      Out.indent(4) << "  CPU: " << TargetOpts.CPU << "\n";
+      Out.indent(4) << "  ABI: " << TargetOpts.ABI << "\n";
+      Out.indent(4) << "  C++ ABI: " << TargetOpts.CXXABI << "\n";
+      Out.indent(4) << "  Linker version: " << TargetOpts.LinkerVersion << "\n";
+
+      if (!TargetOpts.FeaturesAsWritten.empty()) {
+        Out.indent(4) << "Target features:\n";
+        for (unsigned I = 0, N = TargetOpts.FeaturesAsWritten.size();
+             I != N; ++I) {
+          Out.indent(6) << TargetOpts.FeaturesAsWritten[I] << "\n";
+        }
+      }
+
+      return false;
+    }
+
+    virtual bool ReadHeaderSearchOptions(const HeaderSearchOptions &HSOpts,
+                                         bool Complain) {
+      Out.indent(2) << "Header search options:\n";
+      Out.indent(4) << "System root [-isysroot=]: '" << HSOpts.Sysroot << "'\n";
+      DUMP_BOOLEAN(HSOpts.UseBuiltinIncludes,
+                   "Use builtin include directories [-nobuiltininc]");
+      DUMP_BOOLEAN(HSOpts.UseStandardSystemIncludes,
+                   "Use standard system include directories [-nostdinc]");
+      DUMP_BOOLEAN(HSOpts.UseStandardCXXIncludes,
+                   "Use standard C++ include directories [-nostdinc++]");
+      DUMP_BOOLEAN(HSOpts.UseLibcxx,
+                   "Use libc++ (rather than libstdc++) [-stdlib=]");
+      return false;
+    }
+
+    virtual bool ReadPreprocessorOptions(const PreprocessorOptions &PPOpts,
+                                         bool Complain,
+                                         std::string &SuggestedPredefines) {
+      Out.indent(2) << "Preprocessor options:\n";
+      DUMP_BOOLEAN(PPOpts.UsePredefines,
+                   "Uses compiler/target-specific predefines [-undef]");
+      DUMP_BOOLEAN(PPOpts.DetailedRecord,
+                   "Uses detailed preprocessing record (for indexing)");
+
+      if (!PPOpts.Macros.empty()) {
+        Out.indent(4) << "Predefined macros:\n";
+      }
+
+      for (std::vector<std::pair<std::string, bool/*isUndef*/> >::const_iterator
+             I = PPOpts.Macros.begin(), IEnd = PPOpts.Macros.end();
+           I != IEnd; ++I) {
+        Out.indent(6);
+        if (I->second)
+          Out << "-U";
+        else
+          Out << "-D";
+        Out << I->first << "\n";
+      }
+      return false;
+    }
+#undef DUMP_BOOLEAN
+  };
+}
+
+void DumpModuleInfoAction::ExecuteAction() {
+  // Set up the output file.
+  llvm::OwningPtr<llvm::raw_fd_ostream> OutFile;
+  StringRef OutputFileName = getCompilerInstance().getFrontendOpts().OutputFile;
+  if (!OutputFileName.empty() && OutputFileName != "-") {
+    std::string ErrorInfo;
+    OutFile.reset(new llvm::raw_fd_ostream(OutputFileName.str().c_str(),
+                                           ErrorInfo));
+  }
+  llvm::raw_ostream &Out = OutFile.get()? *OutFile.get() : llvm::outs();
+
+  Out << "Information for module file '" << getCurrentFile() << "':\n";
+  DumpModuleInfoListener Listener(Out);
+  ASTReader::readASTFileControlBlock(getCurrentFile(),
+                                     getCompilerInstance().getFileManager(),
+                                     Listener);
+}
+
 //===----------------------------------------------------------------------===//
 // Preprocessor Actions
 //===----------------------------------------------------------------------===//
diff --git a/lib/Frontend/FrontendOptions.cpp b/lib/Frontend/FrontendOptions.cpp
index ea4005f7c9..f1823c69e9 100644
--- a/lib/Frontend/FrontendOptions.cpp
+++ b/lib/Frontend/FrontendOptions.cpp
@@ -13,7 +13,7 @@ using namespace clang;
 
 InputKind FrontendOptions::getInputKindForExtension(StringRef Extension) {
   return llvm::StringSwitch<InputKind>(Extension)
-    .Case("ast", IK_AST)
+    .Cases("ast", "pcm", IK_AST)
     .Case("c", IK_C)
     .Cases("S", "s", IK_Asm)
     .Case("i", IK_PreprocessedC)