Enable streaming of bitcode
This CL delays reading of function bodies from initial parse until
materialization, allowing overlap of compilation with bitcode download.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149918 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/DataStream.cpp b/lib/Support/DataStream.cpp
new file mode 100644
index 0000000..fa8edc7
--- /dev/null
+++ b/lib/Support/DataStream.cpp
@@ -0,0 +1,96 @@
+//===--- llvm/Support/DataStream.cpp - Lazy streamed Data ---===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements DataStreamer, which fetches bytes of Data from
+// a stream source. It provides support for streaming (lazy reading) of
+// bitcode. An example implementation of streaming from a file or stdin
+// is included.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "Data-stream"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/DataStream.h"
+#include "llvm/Support/system_error.h"
+#include <string>
+#include <cerrno>
+#include <cstdio>
+#if !defined(_MSC_VER) && !defined(__MINGW32__)
+#include <unistd.h>
+#else
+#include <io.h>
+#endif
+#include <fcntl.h>
+using namespace llvm;
+
+// Interface goals:
+// * StreamableMemoryObject doesn't care about complexities like using
+// threads/async callbacks to actually overlap download+compile
+// * Don't want to duplicate Data in memory
+// * Don't need to know total Data len in advance
+// Non-goals:
+// StreamableMemoryObject already has random access so this interface only does
+// in-order streaming (no arbitrary seeking, else we'd have to buffer all the
+// Data here in addition to MemoryObject). This also means that if we want
+// to be able to to free Data, BitstreamBytes/BitcodeReader will implement it
+
+STATISTIC(NumStreamFetches, "Number of calls to Data stream fetch");
+
+namespace llvm {
+DataStreamer::~DataStreamer() {}
+}
+
+namespace {
+
+const static error_code success;
+
+// Very simple stream backed by a file. Mostly useful for stdin and debugging;
+// actual file access is probably still best done with mmap.
+class DataFileStreamer : public DataStreamer {
+ int Fd;
+public:
+ DataFileStreamer() : Fd(0) {}
+ virtual ~DataFileStreamer() {
+ close(Fd);
+ }
+ virtual size_t GetBytes(unsigned char *buf, size_t len) {
+ NumStreamFetches++;
+ return read(Fd, buf, len);
+ }
+
+ error_code OpenFile(const std::string &Filename) {
+ int OpenFlags = O_RDONLY;
+#ifdef O_BINARY
+ OpenFlags |= O_BINARY; // Open input file in binary mode on win32.
+#endif
+ if (Filename == "-")
+ Fd = 0;
+ else
+ Fd = ::open(Filename.c_str(), OpenFlags);
+ if (Fd == -1) return error_code(errno, posix_category());
+ return success;
+ }
+};
+
+}
+
+namespace llvm {
+DataStreamer *getDataFileStreamer(const std::string &Filename,
+ std::string *StrError) {
+ DataFileStreamer *s = new DataFileStreamer();
+ error_code e = s->OpenFile(Filename);
+ if (e != success) {
+ *StrError = std::string("Could not open ") + Filename + ": " +
+ e.message() + "\n";
+ return NULL;
+ }
+ return s;
+}
+
+}