Copy LLVM bitcode reader to generate a PNaCl wire format reader.

Copy classes for LLVM BitcodeReader into a NaCl subdirectory, to create a wire
format version. Renames classes/functions to include NaCl prefix, so that
they don't conflict with the LLVM Bitcode reader.

Also implements pnacl-thaw, showing that we can read the PNaCl wire format
files.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3405
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/14314016

4 files changed, 132 insertions, 0 deletions

diff --git a/tools/pnacl-thaw/CMakeLists.txt b/tools/pnacl-thaw/CMakeLists.txt
new file mode 100644
index 0000000000..91b818efe6
--- /dev/null
+++ b/tools/pnacl-thaw/CMakeLists.txt
@@ -0,0 +1,5 @@
+set(LLVM_LINK_COMPONENTS bitwriter naclbitreader)
+
+add_llvm_tool(pnacl-thaw
+  pnacl-thaw.cpp
+  )
diff --git a/tools/pnacl-thaw/LLVMBuild.txt b/tools/pnacl-thaw/LLVMBuild.txt
new file mode 100644
index 0000000000..864da2cbd5
--- /dev/null
+++ b/tools/pnacl-thaw/LLVMBuild.txt
@@ -0,0 +1,16 @@
+;===- ./tools/pnacl-thaw/LLVMBuild.txt -----------------------*- Conf -*--===;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Tool
+name = pnacl-thaw
+parent = Tools
+required_libraries = BitWriter NaClBitReader
diff --git a/tools/pnacl-thaw/Makefile b/tools/pnacl-thaw/Makefile
new file mode 100644
index 0000000000..8e7699e185
--- /dev/null
+++ b/tools/pnacl-thaw/Makefile
@@ -0,0 +1,17 @@
+##===- tools/pnacl-thaw/Makefile ---------------------------*- Makefile -*-===##
+# 
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+# 
+##===----------------------------------------------------------------------===##
+
+LEVEL := ../..
+TOOLNAME := pnacl-thaw
+LINK_COMPONENTS := bitwriter naclbitreader
+
+# This tool has no plugins, optimize startup time.
+TOOL_NO_EXPORTS := 1
+
+include $(LEVEL)/Makefile.common
diff --git a/tools/pnacl-thaw/pnacl-thaw.cpp b/tools/pnacl-thaw/pnacl-thaw.cpp
new file mode 100644
index 0000000000..b28c357165
--- /dev/null
+++ b/tools/pnacl-thaw/pnacl-thaw.cpp
@@ -0,0 +1,94 @@
+/* Copyright 2013 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can
+ * be found in the LICENSE file.
+ */
+
+//===-- pnacl-thaw.cpp - The low-level NaCl bitcode thawer ----------------===//
+//
+//===----------------------------------------------------------------------===//
+//
+// Converts NaCl wire format back to LLVM bitcode.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/IR/LLVMContext.h"
+// Note: We need the following to provide the API for calling the NaCl
+// Bitcode Reader to read the frozen file.
+#include "llvm/Bitcode/NaCl/NaClReaderWriter.h"
+// Note: We need the following to provide the API for calling the (LLVM)
+// Bitcode Writer to generate the corresponding LLVM bitcode file.
+#include "llvm/Bitcode/ReaderWriter.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/DataStream.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/ToolOutputFile.h"
+
+using namespace llvm;
+
+static cl::opt<std::string>
+OutputFilename("o", cl::desc("Specify thawed pexe filename"),
+	       cl::value_desc("filename"));
+
+static cl::opt<std::string>
+InputFilename(cl::Positional, cl::desc("<frozen file>"), cl::Required);
+
+static void WriteOutputFile(const Module *M) {
+
+  std::string ThawedFilename =
+    (OutputFilename.size() == 0 ? (InputFilename + ".thawed") : OutputFilename);
+
+  std::string ErrorInfo;
+  OwningPtr<tool_output_file> Out
+    (new tool_output_file(ThawedFilename.c_str(), ErrorInfo,
+			  raw_fd_ostream::F_Binary));
+  if (!ErrorInfo.empty()) {
+    errs() << ErrorInfo << '\n';
+    exit(1);
+  }
+
+  WriteBitcodeToFile(M, Out->os());
+
+  // Declare success.
+  Out->keep();
+}
+
+int main(int argc, char **argv) {
+  // Print a stack trace if we signal out.
+  sys::PrintStackTraceOnErrorSignal();
+  PrettyStackTraceProgram X(argc, argv);
+
+  LLVMContext &Context = getGlobalContext();
+  llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
+
+  cl::ParseCommandLineOptions(
+      argc, argv, "Converts NaCl pexe wire format into LLVM bitcode format\n");
+
+  std::string ErrorMessage;
+  std::auto_ptr<Module> M;
+
+  // Use the bitcode streaming interface
+  DataStreamer *streamer = getDataFileStreamer(InputFilename, &ErrorMessage);
+  if (streamer) {
+    std::string DisplayFilename = InputFilename;
+    M.reset(getNaClStreamedBitcodeModule(DisplayFilename, streamer, Context,
+                                         &ErrorMessage));
+    if(M.get() != 0 && M->MaterializeAllPermanently(&ErrorMessage)) {
+      M.reset();
+    }
+  }
+
+  if (M.get() == 0) {
+    errs() << argv[0] << ": ";
+    if (ErrorMessage.size())
+      errs() << ErrorMessage << "\n";
+    else
+      errs() << "bitcode didn't read correctly.\n";
+    return 1;
+  }
+
+  WriteOutputFile(M.get());
+  return 0;
+}