[MCJIT] Clean up RuntimeDyld's quirky object-ownership/modification scheme.

Previously, when loading an object file, RuntimeDyld (1) took ownership of the
ObjectFile instance (and associated MemoryBuffer), (2) potentially modified the
object in-place, and (3) returned an ObjectImage that managed ownership of the
now-modified object and provided some convenience methods. This scheme accreted
over several years as features were tacked on to RuntimeDyld, and was both
unintuitive and unsafe (See e.g. http://llvm.org/PR20722).

This patch fixes the issue by removing all ownership and in-place modification
of object files from RuntimeDyld. Existing behavior, including debugger
registration, is preserved.

Noteworthy changes include:

(1) ObjectFile instances are now passed to RuntimeDyld by const-ref.
(2) The ObjectImage and ObjectBuffer classes have been removed entirely, they
    existed to model ownership within RuntimeDyld, and so are no longer needed.
(3) RuntimeDyld::loadObject now returns an instance of a new class,
    RuntimeDyld::LoadedObjectInfo, which can be used to construct a modified
    object suitable for registration with the debugger, following the existing
    debugger registration scheme.
(4) The JITRegistrar class has been removed, and the GDBRegistrar class has been
    re-written as a JITEventListener.

This should fix http://llvm.org/PR20722 .

llvm-svn: 222810

1 files changed, 0 insertions, 86 deletions

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/ObjectImageCommon.h b/llvm/lib/ExecutionEngine/RuntimeDyld/ObjectImageCommon.h
deleted file mode 100644
index 9bbf6a0d809..00000000000
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/ObjectImageCommon.h
+++ /dev/null
@@ -1,86 +0,0 @@
-//===-- ObjectImageCommon.h - Format independent executuable object image -===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file declares a file format independent ObjectImage class.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_OBJECTIMAGECOMMON_H
-#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_OBJECTIMAGECOMMON_H
-
-#include "llvm/ExecutionEngine/ObjectBuffer.h"
-#include "llvm/ExecutionEngine/ObjectImage.h"
-#include "llvm/Object/ObjectFile.h"
-
-#include <memory>
-
-namespace llvm {
-
-namespace object {
-  class ObjectFile;
-}
-
-class ObjectImageCommon : public ObjectImage {
-  ObjectImageCommon(); // = delete
-  ObjectImageCommon(const ObjectImageCommon &other); // = delete
-  void anchor() override;
-
-protected:
-  std::unique_ptr<object::ObjectFile> ObjFile;
-
-  // This form of the constructor allows subclasses to use
-  // format-specific subclasses of ObjectFile directly
-  ObjectImageCommon(std::unique_ptr<ObjectBuffer> Input,
-                    std::unique_ptr<object::ObjectFile> Obj)
-      : ObjectImage(std::move(Input)), ObjFile(std::move(Obj)) {}
-
-public:
-  ObjectImageCommon(std::unique_ptr<ObjectBuffer> Input)
-      : ObjectImage(std::move(Input)) {
-    // FIXME: error checking? createObjectFile returns an ErrorOr<ObjectFile*>
-    // and should probably be checked for failure.
-    MemoryBufferRef Buf = Buffer->getMemBuffer();
-    ObjFile = std::move(object::ObjectFile::createObjectFile(Buf).get());
-  }
-  ObjectImageCommon(std::unique_ptr<object::ObjectFile> Input)
-  : ObjectImage(nullptr), ObjFile(std::move(Input))  {}
-  virtual ~ObjectImageCommon() { }
-
-  object::symbol_iterator begin_symbols() const override
-      { return ObjFile->symbol_begin(); }
-  object::symbol_iterator end_symbols() const override
-      { return ObjFile->symbol_end(); }
-
-  object::section_iterator begin_sections() const override
-      { return ObjFile->section_begin(); }
-  object::section_iterator end_sections() const override
-      { return ObjFile->section_end(); }
-
-  /* Triple::ArchType */ unsigned getArch() const override
-      { return ObjFile->getArch(); }
-
-  StringRef getData() const override { return ObjFile->getData(); }
-
-  object::ObjectFile* getObjectFile() const override { return ObjFile.get(); }
-
-  // Subclasses can override these methods to update the image with loaded
-  // addresses for sections and common symbols
-  void updateSectionAddress(const object::SectionRef &Sec,
-                            uint64_t Addr) override {}
-  void updateSymbolAddress(const object::SymbolRef &Sym,
-                           uint64_t Addr) override {}
-
-  // Subclasses can override these methods to provide JIT debugging support
-  void registerWithDebugger() override {}
-  void deregisterWithDebugger() override {}
-};
-
-} // end namespace llvm
-
-#endif