Bitcode streaming

lib/Bitcode/Reader/BitcodeReader.cpp

Index: lib/Bitcode/Reader/BitcodeReader.cpp
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 46565f36af16117244097a77de3dc314a82fdd51..5dc2c69b1dbe23143bb4b98b1d065683100ccc7f 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -13,6 +13,7 @@
 
 #include "llvm/Bitcode/ReaderWriter.h"
 #include "BitcodeReader.h"
+#include "llvm/Bitcode/BitcodeStream.h"
 #include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/InlineAsm.h"
@@ -1823,25 +1824,8 @@ bool BitcodeReader::ParseModule() {
 
 bool BitcodeReader::ParseBitcodeInto(Module *M) {
   TheModule = 0;
-
-  unsigned char *BufPtr = (unsigned char *)Buffer->getBufferStart();
-  unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
-
-  if (Buffer->getBufferSize() & 3) {
-    if (!isRawBitcode(BufPtr, BufEnd) && !isBitcodeWrapper(BufPtr, BufEnd))
-      return Error("Invalid bitcode signature");
-    else
-      return Error("Bitcode stream should be a multiple of 4 bytes in length");
-  }
-
-  // If we have a wrapper header, parse it and ignore the non-bc file contents.
-  // The magic number is 0x0B17C0DE stored in little endian.
-  if (isBitcodeWrapper(BufPtr, BufEnd))
-    if (SkipBitcodeWrapperHeader(BufPtr, BufEnd))
-      return Error("Invalid bitcode wrapper header");
-
-  StreamFile.init(BufPtr, BufEnd);
-  Stream.init(StreamFile);
+  bool err;
+  if ((err = InitStream())) return err;

[nlewycky, 2011/11/05 00:45:06]

if (InitStream()) return true;

[(google.com) Derek Schuff, 2011/11/07 22:33:50]

Done.

 
   // Sniff for the signature.
   if (Stream.Read(8) != 'B' ||
@@ -1952,20 +1936,8 @@ bool BitcodeReader::ParseModuleTriple(std::string &Triple) {
 }
 
 bool BitcodeReader::ParseTriple(std::string &Triple) {
-  if (Buffer->getBufferSize() & 3)
-    return Error("Bitcode stream should be a multiple of 4 bytes in length");
-
-  unsigned char *BufPtr = (unsigned char *)Buffer->getBufferStart();
-  unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
-
-  // If we have a wrapper header, parse it and ignore the non-bc file contents.
-  // The magic number is 0x0B17C0DE stored in little endian.
-  if (isBitcodeWrapper(BufPtr, BufEnd))
-    if (SkipBitcodeWrapperHeader(BufPtr, BufEnd))
-      return Error("Invalid bitcode wrapper header");
-
-  StreamFile.init(BufPtr, BufEnd);
-  Stream.init(StreamFile);
+  bool err;
+  if ((err = InitStream())) return err;

[nlewycky, 2011/11/05 00:45:06]

again

[(google.com) Derek Schuff, 2011/11/07 22:33:50]

Done.

 
   // Sniff for the signature.
   if (Stream.Read(8) != 'B' ||
@@ -2948,6 +2920,56 @@ bool BitcodeReader::MaterializeModule(Module *M, std::string *ErrInfo) {
   return false;
 }
 
+bool BitcodeReader::InitStream() {
+  if (LazyStreamer) return InitLazyStream();
+  else return InitStreamFromBuffer();

[nlewycky, 2011/11/05 00:45:06]

Delete the "else". See
http://llvm.org/docs/CodingStandards.html#hl_else_after_return

+}
+
+bool BitcodeReader::InitStreamFromBuffer() {
+  const unsigned char *BufPtr = (unsigned char *)Buffer->getBufferStart();
+  const unsigned char *BufEnd = BufPtr+Buffer->getBufferSize();
+
+  if (Buffer->getBufferSize() & 3) {
+    if (!isRawBitcode(BufPtr, BufEnd) && !isBitcodeWrapper(BufPtr, BufEnd))
+      return Error("Invalid bitcode signature");
+    else
+      return Error("Bitcode stream should be a multiple of 4 bytes in length");
+  }
+
+  // If we have a wrapper header, parse it and ignore the non-bc file contents.
+  // The magic number is 0x0B17C0DE stored in little endian.
+  if (isBitcodeWrapper(BufPtr, BufEnd))
+    if (SkipBitcodeWrapperHeader(BufPtr, BufEnd, true))
+      return Error("Invalid bitcode wrapper header");
+
+  StreamFile.reset(new BitstreamReader(BufPtr, BufEnd));
+  Stream.init(*StreamFile);
+
+  return false;
+}
+
+bool BitcodeReader::InitLazyStream() {
+  // Check and strip off the bitcode wrapper; BitstreamReader expects never to
+  // see it.
+  LazyBitstreamVector *BSV = new LazyBitstreamVector(LazyStreamer);
+  StreamFile.reset(new BitstreamReader(BSV));
+  Stream.init(*StreamFile);
+  if (!BSV->canSkipToPos(15))
+    return Error("Bitcode stream must be at least 16 bytes in length");
+  unsigned char buf[16];
+  for (int i = 0; i < 16; i++) buf[i] = BSV->operator[](i);

[nlewycky, 2011/11/05 00:45:06]

(*BSV)[i]

[(google.com) Derek Schuff, 2011/11/07 22:33:50]

Done.

+  if (!isBitcode(buf, buf + 16)) {
+    return Error("Invalid bitcode signature");
+  }
+  if (isBitcodeWrapper(buf, buf + 4)) {
+    const unsigned char *bitcodeStart = buf;
+    const unsigned char *bitcodeEnd = buf + 16;
+    SkipBitcodeWrapperHeader(bitcodeStart, bitcodeEnd, false);
+    BSV->dropLeadingBytes(bitcodeStart - buf);
+    BSV->setKnownBitcodeSize(bitcodeEnd - bitcodeStart);
+  }
+  return false;
+}
 
 //===----------------------------------------------------------------------===//
 // External interface
@@ -2973,6 +2995,24 @@ Module *llvm::getLazyBitcodeModule(MemoryBuffer *Buffer,
   return M;
 }
 
+
+Module *llvm::getStreamedBitcodeModule(const std::string& name,
+                                   BitcodeStreamer* streamer,
+                                   LLVMContext& Context,
+                                   std::string *ErrMsg) {
+  Module *M = new Module(name, Context);
+  BitcodeReader *R = new BitcodeReader(streamer, Context);
+  M->setMaterializer(R);
+  if (R->ParseBitcodeInto(M)) {
+    if (ErrMsg)
+      *ErrMsg = R->getErrorString();
+    delete M; //Also deletes R.

[nlewycky, 2011/11/05 00:45:06]

Space after //

[(google.com) Derek Schuff, 2011/11/07 22:33:50]

Done.

+    return 0;
+  }
+  R->setBufferOwned(false); // no buffer to delete
+  return M;
+}
+
 /// ParseBitcodeFile - Read the specified bitcode file, returning the module.
 /// If an error occurs, return null and fill in *ErrMsg if non-null.
 Module *llvm::ParseBitcodeFile(MemoryBuffer *Buffer, LLVMContext& Context,