Add -frewrite-imports flag.

If specified, when preprocessing, the contents of imported .pcm files will be
included in preprocessed output. The resulting preprocessed file can then be
compiled standalone without the module sources or .pcm files.

llvm-svn: 305116

1 files changed, 104 insertions, 14 deletions

diff --git a/clang/lib/Frontend/Rewrite/FrontendActions.cpp b/clang/lib/Frontend/Rewrite/FrontendActions.cpp
index 76eb07e981d..45feffbcb5b 100644
--- a/clang/lib/Frontend/Rewrite/FrontendActions.cpp
+++ b/clang/lib/Frontend/Rewrite/FrontendActions.cpp
@@ -18,6 +18,11 @@
 #include "clang/Rewrite/Frontend/ASTConsumers.h"
 #include "clang/Rewrite/Frontend/FixItRewriter.h"
 #include "clang/Rewrite/Frontend/Rewriters.h"
+#include "clang/Serialization/ASTReader.h"
+#include "clang/Serialization/Module.h"
+#include "clang/Serialization/ModuleManager.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/Support/CrashRecoveryContext.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
@@ -189,27 +194,112 @@ void RewriteTestAction::ExecuteAction() {
   DoRewriteTest(CI.getPreprocessor(), OS.get());
 }
 
-void RewriteIncludesAction::ExecuteAction() {
-  CompilerInstance &CI = getCompilerInstance();
-  std::unique_ptr<raw_ostream> OS =
-      CI.createDefaultOutputFile(true, getCurrentFile());
-  if (!OS) return;
+class RewriteIncludesAction::RewriteImportsListener : public ASTReaderListener {
+  CompilerInstance &CI;
+  std::weak_ptr<raw_ostream> Out;
+
+  llvm::DenseSet<const FileEntry*> Rewritten;
+
+public:
+  RewriteImportsListener(CompilerInstance &CI, std::shared_ptr<raw_ostream> Out)
+      : CI(CI), Out(Out) {}
+
+  void visitModuleFile(StringRef Filename,
+                       serialization::ModuleKind Kind) override {
+    auto *File = CI.getFileManager().getFile(Filename);
+    assert(File && "missing file for loaded module?");
+
+    // Only rewrite each module file once.
+    if (!Rewritten.insert(File).second)
+      return;
+
+    serialization::ModuleFile *MF =
+        CI.getModuleManager()->getModuleManager().lookup(File);
+    assert(File && "missing module file for loaded module?");
+
+    // Not interested in PCH / preambles.
+    if (!MF->isModule())
+      return;
+
+    auto OS = Out.lock();
+    assert(OS && "loaded module file after finishing rewrite action?");
+
+    (*OS) << "#pragma clang module build " << MF->ModuleName << "\n";
+
+    // Rewrite the contents of the module in a separate compiler instance.
+    CompilerInstance Instance(CI.getPCHContainerOperations(),
+                              &CI.getPreprocessor().getPCMCache());
+    Instance.setInvocation(
+        std::make_shared<CompilerInvocation>(CI.getInvocation()));
+    Instance.createDiagnostics(
+        new ForwardingDiagnosticConsumer(CI.getDiagnosticClient()),
+        /*ShouldOwnClient=*/true);
+    Instance.getFrontendOpts().Inputs.clear();
+    Instance.getFrontendOpts().Inputs.emplace_back(
+        Filename, InputKind(InputKind::Unknown, InputKind::Precompiled));
+    // Don't recursively rewrite imports. We handle them all at the top level.
+    Instance.getPreprocessorOutputOpts().RewriteImports = false;
+
+    llvm::CrashRecoveryContext().RunSafelyOnThread([&]() {
+      RewriteIncludesAction Action;
+      Action.OutputStream = OS;
+      Instance.ExecuteAction(Action);
+    });
+
+    (*OS) << "#pragma clang module endbuild /*" << MF->ModuleName << "*/\n";
+  }
+};
+
+bool RewriteIncludesAction::BeginSourceFileAction(CompilerInstance &CI) {
+  if (!OutputStream) {
+    OutputStream = CI.createDefaultOutputFile(true, getCurrentFile());
+    if (!OutputStream)
+      return false;
+  }
+
+  auto &OS = *OutputStream;
 
   // If we're preprocessing a module map, start by dumping the contents of the
   // module itself before switching to the input buffer.
   auto &Input = getCurrentInput();
   if (Input.getKind().getFormat() == InputKind::ModuleMap) {
     if (Input.isFile()) {
-      (*OS) << "# 1 \"";
-      OS->write_escaped(Input.getFile());
-      (*OS) << "\"\n";
+      OS << "# 1 \"";
+      OS.write_escaped(Input.getFile());
+      OS << "\"\n";
     }
-    // FIXME: Include additional information here so that we don't need the
-    // original source files to exist on disk.
-    getCurrentModule()->print(*OS);
-    (*OS) << "#pragma clang module contents\n";
+    getCurrentModule()->print(OS);
+    OS << "#pragma clang module contents\n";
+  }
+
+  // If we're rewriting imports, set up a listener to track when we import
+  // module files.
+  if (CI.getPreprocessorOutputOpts().RewriteImports) {
+    CI.createModuleManager();
+    CI.getModuleManager()->addListener(
+        llvm::make_unique<RewriteImportsListener>(CI, OutputStream));
+  }
+
+  return true;
+}
+
+void RewriteIncludesAction::ExecuteAction() {
+  CompilerInstance &CI = getCompilerInstance();
+
+  // If we're rewriting imports, emit the module build output first rather
+  // than switching back and forth (potentially in the middle of a line).
+  if (CI.getPreprocessorOutputOpts().RewriteImports) {
+    std::string Buffer;
+    llvm::raw_string_ostream OS(Buffer);
+
+    RewriteIncludesInInput(CI.getPreprocessor(), &OS,
+                           CI.getPreprocessorOutputOpts());
+
+    (*OutputStream) << OS.str();
+  } else {
+    RewriteIncludesInInput(CI.getPreprocessor(), OutputStream.get(),
+                           CI.getPreprocessorOutputOpts());
   }
 
-  RewriteIncludesInInput(CI.getPreprocessor(), OS.get(),
-                         CI.getPreprocessorOutputOpts());
+  OutputStream.reset();
 }