vendor/llvm/llvm-trunk-r238337

1 files changed, 77 insertions, 0 deletions

diff --git a/include/llvm/ExecutionEngine/Orc/JITSymbol.h b/include/llvm/ExecutionEngine/Orc/JITSymbol.h
new file mode 100644
index 000000000000..422a3761837c
--- /dev/null
+++ b/include/llvm/ExecutionEngine/Orc/JITSymbol.h
@@ -0,0 +1,77 @@
+//===----------- JITSymbol.h - JIT symbol abstraction -----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Abstraction for target process addresses.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_EXECUTIONENGINE_ORC_JITSYMBOL_H
+#define LLVM_EXECUTIONENGINE_ORC_JITSYMBOL_H
+
+#include "llvm/ExecutionEngine/JITSymbolFlags.h"
+#include "llvm/Support/DataTypes.h"
+#include <cassert>
+#include <functional>
+
+namespace llvm {
+namespace orc {
+
+/// @brief Represents an address in the target process's address space.
+typedef uint64_t TargetAddress;
+
+/// @brief Represents a symbol in the JIT.
+class JITSymbol : public JITSymbolBase {
+public:
+
+  typedef std::function<TargetAddress()> GetAddressFtor;
+
+  /// @brief Create a 'null' symbol that represents failure to find a symbol
+  ///        definition.
+  JITSymbol(std::nullptr_t)
+      : JITSymbolBase(JITSymbolFlags::None), CachedAddr(0) {}
+
+  /// @brief Create a symbol for a definition with a known address.
+  JITSymbol(TargetAddress Addr, JITSymbolFlags Flags)
+    : JITSymbolBase(Flags), CachedAddr(Addr) {}
+
+  /// @brief Create a symbol for a definition that doesn't have a known address
+  ///        yet.
+  /// @param GetAddress A functor to materialize a definition (fixing the
+  ///        address) on demand.
+  ///
+  ///   This constructor allows a JIT layer to provide a reference to a symbol
+  /// definition without actually materializing the definition up front. The
+  /// user can materialize the definition at any time by calling the getAddress
+  /// method.
+  JITSymbol(GetAddressFtor GetAddress, JITSymbolFlags Flags)
+      : JITSymbolBase(Flags), GetAddress(std::move(GetAddress)), CachedAddr(0) {}
+
+  /// @brief Returns true if the symbol exists, false otherwise.
+  explicit operator bool() const { return CachedAddr || GetAddress; }
+
+  /// @brief Get the address of the symbol in the target address space. Returns
+  ///        '0' if the symbol does not exist.
+  TargetAddress getAddress() {
+    if (GetAddress) {
+      CachedAddr = GetAddress();
+      assert(CachedAddr && "Symbol could not be materialized.");
+      GetAddress = nullptr;
+    }
+    return CachedAddr;
+  }
+
+private:
+  GetAddressFtor GetAddress;
+  TargetAddress CachedAddr;
+};
+
+} // End namespace orc.
+} // End namespace llvm.
+
+#endif // LLVM_EXECUTIONENGINE_ORC_JITSYMBOL_H