From c29284e6c374f9e6058998238c4bd8c3adfd9291 Mon Sep 17 00:00:00 2001
From: Joseph Tremoulet <jotrem@microsoft.com>
Date: Mon, 22 Jun 2015 15:27:58 +0000
Subject: [PATCH] [ORC] Add NullResolver

Summary:
This is an implementation of RuntimeDyld::SymbolResolver that simply
rejects all resolution requests; useful for clients that do not have any
cross-object symbol references.

Reviewers: lhames

Reviewed By: lhames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D10455

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240288 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../llvm/ExecutionEngine/Orc/NullResolver.h   | 36 +++++++++++++++++++
 lib/ExecutionEngine/Orc/CMakeLists.txt        | 25 ++++++-------
 lib/ExecutionEngine/Orc/NullResolver.cpp      | 27 ++++++++++++++
 3 files changed, 76 insertions(+), 12 deletions(-)
 create mode 100644 include/llvm/ExecutionEngine/Orc/NullResolver.h
 create mode 100644 lib/ExecutionEngine/Orc/NullResolver.cpp

diff --git a/include/llvm/ExecutionEngine/Orc/NullResolver.h b/include/llvm/ExecutionEngine/Orc/NullResolver.h
new file mode 100644
index 00000000000..df1d9e8518d
--- /dev/null
+++ b/include/llvm/ExecutionEngine/Orc/NullResolver.h
@@ -0,0 +1,36 @@
+//===------ NullResolver.h - Reject symbol lookup requests ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//   Defines a RuntimeDyld::SymbolResolver subclass that rejects all symbol
+// resolution requests, for clients that have no cross-object fixups.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_ORC_NULLRESOLVER_H
+#define LLVM_EXECUTIONENGINE_ORC_NULLRESOLVER_H
+
+#include "llvm/ExecutionEngine/RuntimeDyld.h"
+
+namespace llvm {
+namespace orc {
+
+/// SymbolResolver impliementation that rejects all resolution requests.
+/// Useful for clients that have no cross-object fixups.
+class NullResolver : public RuntimeDyld::SymbolResolver {
+public:
+  RuntimeDyld::SymbolInfo findSymbol(const std::string &Name) final;
+
+  RuntimeDyld::SymbolInfo
+  findSymbolInLogicalDylib(const std::string &Name) final;
+};
+
+} // End namespace orc.
+} // End namespace llvm.
+
+#endif // LLVM_EXECUTIONENGINE_ORC_NULLRESOLVER_H
diff --git a/lib/ExecutionEngine/Orc/CMakeLists.txt b/lib/ExecutionEngine/Orc/CMakeLists.txt
index 1da164237a6..05fb5a30bcd 100644
--- a/lib/ExecutionEngine/Orc/CMakeLists.txt
+++ b/lib/ExecutionEngine/Orc/CMakeLists.txt
@@ -1,12 +1,13 @@
-add_llvm_library(LLVMOrcJIT
-  ExecutionUtils.cpp
-  IndirectionUtils.cpp
-  OrcMCJITReplacement.cpp
-  OrcTargetSupport.cpp
-
-  ADDITIONAL_HEADER_DIRS
-  ${LLVM_MAIN_INCLUDE_DIR}/llvm/ExecutionEngine/Orc
-
-  DEPENDS
-  intrinsics_gen
-  )
+add_llvm_library(LLVMOrcJIT
+  ExecutionUtils.cpp
+  IndirectionUtils.cpp
+  NullResolver.cpp
+  OrcMCJITReplacement.cpp
+  OrcTargetSupport.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${LLVM_MAIN_INCLUDE_DIR}/llvm/ExecutionEngine/Orc
+
+  DEPENDS
+  intrinsics_gen
+  )
diff --git a/lib/ExecutionEngine/Orc/NullResolver.cpp b/lib/ExecutionEngine/Orc/NullResolver.cpp
new file mode 100644
index 00000000000..5b91b0acbaa
--- /dev/null
+++ b/lib/ExecutionEngine/Orc/NullResolver.cpp
@@ -0,0 +1,27 @@
+//===---------- NullResolver.cpp - Reject symbol lookup requests ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ExecutionEngine/Orc/NullResolver.h"
+
+#include "llvm/Support/ErrorHandling.h"
+
+namespace llvm {
+namespace orc {
+
+RuntimeDyld::SymbolInfo NullResolver::findSymbol(const std::string &Name) {
+  llvm_unreachable("Unexpected cross-object symbol reference");
+}
+
+RuntimeDyld::SymbolInfo
+NullResolver::findSymbolInLogicalDylib(const std::string &Name) {
+  llvm_unreachable("Unexpected cross-object symbol reference");
+}
+
+} // End namespace orc.
+} // End namespace llvm.