[XRay] Implement `llvm-xray extract`, start of the llvm-xray tool

Usage:

  llvm-xray extract <object file> [-o <filename or '-'>]

The tool gets the XRay instrumentation map from an object file and turns
it into YAML.  We first support ELF64 sleds on x86_64 binaries, with
provision for supporting other supported platforms and formats later.

This is the first of a many-part change to fully implement the
`llvm-xray` tool.

We also define a subcommand registration and dispatch mechanism to be
used by other further subcommand implementations for llvm-xray.

llvm-svn: 285155

1 files changed, 58 insertions, 0 deletions

diff --git a/llvm/tools/llvm-xray/xray-extract.h b/llvm/tools/llvm-xray/xray-extract.h
new file mode 100644
index 00000000000..91e4db36805
--- /dev/null
+++ b/llvm/tools/llvm-xray/xray-extract.h
@@ -0,0 +1,58 @@
+//===- xray-extract.h - XRay Instrumentation Map Extraction ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines the interface for extracting the instrumentation map from an
+// XRay-instrumented binary.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_XRAY_EXTRACT_H
+#define LLVM_TOOLS_XRAY_EXTRACT_H
+
+#include <deque>
+#include <map>
+#include <string>
+#include <unordered_map>
+
+#include "xray-sleds.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+namespace xray {
+
+class InstrumentationMapExtractor {
+public:
+  typedef std::unordered_map<int32_t, uint64_t> FunctionAddressMap;
+  typedef std::unordered_map<uint64_t, int32_t> FunctionAddressReverseMap;
+
+  enum class InputFormats { ELF, YAML };
+
+private:
+  std::deque<SledEntry> Sleds;
+  FunctionAddressMap FunctionAddresses;
+  FunctionAddressReverseMap FunctionIds;
+
+public:
+  /// Loads the instrumentation map from |Filename|. Updates |EC| in case there
+  /// were errors encountered opening the file. |Format| defines what the input
+  /// instrumentation map is in.
+  InstrumentationMapExtractor(std::string Filename, InputFormats Format,
+                              Error &EC);
+
+  const FunctionAddressMap &getFunctionAddresses() { return FunctionAddresses; }
+
+  /// Exports the loaded function address map as YAML through |OS|.
+  void exportAsYAML(raw_ostream &OS);
+};
+
+} // namespace xray
+} // namespace llvm
+
+#endif // LLVM_TOOLS_XRAY_EXTRACT_H