Clang plugin that rewrites PostTask(_, NewRunnableMethod(...)) to PostTask(_, base::Bind(...));

tools/clang/BindMigrate/BindMigrateConsumer.cpp

+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: ajwong@google.com (Albert Wong)
+
+#include <iostream>
+#include <string>
+
+#include "BindMigrateConsumer.h"
+
+#include "clang/AST/AST.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/DeclGroup.h"
+#include "clang/AST/DeclVisitor.h"
+#include "clang/AST/DeclarationName.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/ParentMap.h"
+#include "clang/AST/StmtVisitor.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/AST/TypeLocVisitor.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/Basic/IdentifierTable.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Index/DeclReferenceMap.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Rewrite/ASTConsumers.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+#include "clang/Frontend/CompilerInstance.h"
+
+#include "FileRemapper.h"
+#include "TransformPostTask.h"
+
+using namespace std;
+
+namespace clang {
+
+BindMigrateConsumer::BindMigrateConsumer(CompilerInstance* instance,
+                                         arcmt_hack::FileRemapper* remapper)
+    : instance_(instance),
+      error_emitter_(instance, "[bind-migrate] "),
+      remapper_(remapper) {
+}
+
+BindMigrateConsumer::~BindMigrateConsumer() {
+}
+
+void BindMigrateConsumer::Initialize(ASTContext &context) {
+  rewriter_.setSourceMgr(context.getSourceManager(), context.getLangOptions());
+}
+
+void BindMigrateConsumer::HandleTranslationUnit(ASTContext &context) {
+  TransformPostTask visitor(&context, &rewriter_, &error_emitter_);
+
+  // modify calls
+  TranslationUnitDecl *translation_unit = context.getTranslationUnitDecl();
+  for (DeclContext::decl_iterator it = translation_unit->decls_begin(),
+       end = translation_unit->decls_end(); it != end; ++it) {
+    // TODO(ajwong): Could test for
+    //
+    //   context.getSourceManager()->isFromMainFile((*it)->getLocation())
+    //
+    // here to skip everything but the main file.
+    visitor.TraverseDecl(*it);
+  }
+
+  // Get the buffer corresponding to MainFileID.
+  for (Rewriter::buffer_iterator it = rewriter_.buffer_begin();
+       it != rewriter_.buffer_end();
+       ++it) {
+    const FileEntry *file =
+        context.getSourceManager().getFileEntryForID(it->first);
+    assert(file);
+
+    std::string new_filename = file->getName();
+    new_filename += "-trans";
+    llvm::SmallString<512> new_text;
+    llvm::raw_svector_ostream vecOS(new_text);
+    it->second.write(vecOS);
+    vecOS.flush();
+    llvm::MemoryBuffer *mem_buf = llvm::MemoryBuffer::getMemBufferCopy(
+        StringRef(new_text.data(), new_text.size()), new_filename);
+    llvm::SmallString<64> orig_filename(file->getName());
+    instance_->getFileManager().FixupRelativePath(orig_filename);
+    remapper_->remap(orig_filename.str(), mem_buf);
+  }
+
+
+  // TODO(ajwong): We should just hook into BeginInvocation() like ARCMigrate
+  // does.  As is, it is hard to flush at the end of the compilation sequence
+  // because there's no such thing as EndInvocation().

[Nico, 2011/09/16 03:00:54]

HandleTranslationUnit() is called only after everything's done. Maybe I'm
misunderstanding your comment.

[awong, 2011/09/16 10:24:32]

I misunderstood BeginInvocation.

What I was trying to say is that HandleTranslationUnit gets called after each
translation unit is completed...but if you list multiple .cc files (eg., clang++
a.cc b.cc) this will be called once per file.

Ideally, I'd like to be able to say something like remapper.flushToDisk() on
each TranslationUnit which will create a temporary file for each modified file. 


Then at the end of a compiler invocation, either commit the temporary files into
a new directory, or overwrite the originals.  But to do this, I need something
that is run after all translation units are processed.

ARCMigrate solves this a different way...which may actually be nicer.

They actually invoke the compiler 2 times per file inside the BeginInvocation
step before the "real" compilation.

The first time sanity checks that the file parses at all as valid C++.  The
second time is where they actually do the migration.  Then they return out of
BeginInvocation, and allow Clang to try and compile the migrated files.

During the first two compiles it looks like they capture and discard most
Diagnostics by default.  I *think* this lets them deal with partially migrated
code when doing an in place migration.

For BindMigrate, I'm not sure if it's worth bothering with the multiple
compilation steps.  The effect is we'd compile the old source files...but maybe
we don't care for now.

+  remapper_->writeParallelTree("/tmp/whatevs", instance_->getDiagnostics());
+}
+
+}  // namespace clang