Initial support for reading bitcode files. They currently only read types,
the type symtab, and global/function protos, and are missing the important
size optimization, but it is a place to start.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36330 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bitcode/Reader/ReaderWrappers.cpp b/lib/Bitcode/Reader/ReaderWrappers.cpp
new file mode 100644
index 0000000..7f6a809
--- /dev/null
+++ b/lib/Bitcode/Reader/ReaderWrappers.cpp
@@ -0,0 +1,97 @@
+//===- ReaderWrappers.cpp - Parse bitcode from file or buffer -------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Chris Lattner and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements loading and parsing a bitcode file and parsing a
+// module from a memory buffer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bitcode/ReaderWriter.h"
+#include "BitcodeReader.h"
+#include "llvm/System/MappedFile.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+// BitcodeFileReader - Read from an mmap'able file descriptor.
+
+namespace {
+ /// BitcodeFileReader - parses bitcode from a file.
+ ///
+ class BitcodeFileReader : public BitcodeReader {
+ private:
+ std::string Filename;
+ sys::MappedFile File;
+
+ BitcodeFileReader(const BitcodeFileReader&); // DO NOT IMPLEMENT
+ void operator=(const BitcodeFileReader&); // DO NOT IMPLEMENT
+ public:
+ BitcodeFileReader(const std::string &FN) : Filename(FN) {}
+ bool Read(std::string *ErrMsg);
+
+ void FreeState() {
+ BitcodeReader::FreeState();
+ File.close();
+ }
+ };
+}
+
+bool BitcodeFileReader::Read(std::string *ErrMsg) {
+ if (File.open(sys::Path(Filename), sys::MappedFile::READ_ACCESS, ErrMsg))
+ return true;
+ if (!File.map(ErrMsg)) {
+ File.close();
+ return true;
+ }
+ unsigned char *Buffer = reinterpret_cast<unsigned char*>(File.base());
+ if (!ParseBitcode(Buffer, File.size(), Filename))
+ return false;
+ if (ErrMsg) *ErrMsg = getErrorString();
+ return true;
+}
+
+
+
+//===----------------------------------------------------------------------===//
+// External interface
+//===----------------------------------------------------------------------===//
+
+/// getBitcodeModuleProvider - lazy function-at-a-time loading from a file.
+///
+ModuleProvider *llvm::getBitcodeModuleProvider(const std::string &Filename,
+ std::string *ErrMsg) {
+ if (Filename != std::string("-")) {
+ BitcodeFileReader *R = new BitcodeFileReader(Filename);
+ if (R->Read(ErrMsg)) {
+ delete R;
+ return 0;
+ }
+ return R;
+ }
+
+ assert(0 && "FIXME: stdin reading unimp!");
+#if 0
+ // Read from stdin
+ BytecodeStdinReader *R = new BytecodeStdinReader();
+ if (R->Read(ErrMsg)) {
+ delete R;
+ return 0;
+ }
+ return R;
+#endif
+}
+
+/// 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(const std::string &Filename,std::string *ErrMsg){
+ ModuleProvider *MP = getBitcodeModuleProvider(Filename, ErrMsg);
+ if (!MP) return 0;
+ Module *M = MP->releaseModule(ErrMsg);
+ delete MP;
+ return M;
+}