C bindings for libLLVMCore.a and libLLVMBitWriter.a.

- The naming prefix is LLVM.
- All types are represented using opaque references.
- Functions are not named LLVM{Type}{Method}; the names became
  unreadable goop. Instead, they are named LLVM{ImperativeSentence}.
- Where an attribute only appears once in the class hierarchy (e.g.,
  linkage only applies to values; parameter types only apply to
  function types), the class is omitted from identifiers for
  brevity. Tastes like methods.
- Strings are C strings or string/length tuples on a case-by-case
  basis.
- APIs which give the caller ownership of an object are not mapped
  (removeFromParent, certain constructor overloads). This keeps
  keep memory management as simple as possible.

For each library with bindings:

  llvm-c/<LIB>.h       - Declares the bindings.
  lib/<LIB>/<LIB>.cpp  - Implements the bindings.

So just link with the library of your choice and use the C header
instead of the C++ one.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42077 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Bitcode/Writer/BitWriter.cpp

@@ -0,0 +1,51 @@
+//===-- BitWriter.cpp -----------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm-c/BitWriter.h"
+#include "llvm/CHelpers.h"
+#include "llvm/Bitcode/ReaderWriter.h"
+#include <fstream>
+
+using namespace llvm;
+
+
+/*===-- Operations on modules ---------------------------------------------===*/
+
+int LLVMWriteBitcodeToFile(LLVMModuleRef M, const char *Path) {
+  std::ofstream OS(Path);
+  
+  if (!OS.fail())
+    WriteBitcodeToFile(unwrap(M), OS);
+  
+  if (OS.fail())
+    return -1;
+  
+  return 0;
+}
+
+#ifdef __GNUC__
+#include <ext/stdio_filebuf.h>
+
+// FIXME: Control this with configure? Provide some portable abstraction in
+// libSystem? As is, the user will just get a linker error if they use this on 
+// non-GCC. Some C++ stdlibs even have ofstream::ofstream(int fd).
+int LLVMWriteBitcodeToFileHandle(LLVMModuleRef M, int FileHandle) {
+  __gnu_cxx::stdio_filebuf<char> Buffer(FileHandle, std::ios_base::out);
+  std::ostream OS(&Buffer);
+  
+  if (!OS.fail())
+    WriteBitcodeToFile(unwrap(M), OS);
+  
+  if (OS.fail())
+    return -1;
+  
+  return 0;
+}
+
+#endif