[ORC-RT] Add missing file that was left out of ff846fc.

Author: lhames

compiler-rt/lib/orc/macho_ehframe_registration.cpp

@@ -0,0 +1,68 @@
+//===- ehframe_registration.cpp -------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains code required to load the rest of the MachO runtime.
+//
+//===----------------------------------------------------------------------===//
+
+#include "adt.h"
+#include "c_api.h"
+#include "common.h"
+
+using namespace __orc_rt;
+
+// eh-frame registration functions.
+// We expect these to be available for all processes.
+extern "C" void __register_frame(const void *);
+extern "C" void __deregister_frame(const void *);
+
+namespace {
+
+template <typename HandleFDEFn>
+void walkEHFrameSection(span<const char> EHFrameSection,
+                        HandleFDEFn HandleFDE) {
+  const char *CurCFIRecord = EHFrameSection.data();
+  uint64_t Size = *reinterpret_cast<const uint32_t *>(CurCFIRecord);
+
+  while (CurCFIRecord != EHFrameSection.end() && Size != 0) {
+    const char *OffsetField = CurCFIRecord + (Size == 0xffffffff ? 12 : 4);
+    if (Size == 0xffffffff)
+      Size = *reinterpret_cast<const uint64_t *>(CurCFIRecord + 4) + 12;
+    else
+      Size += 4;
+    uint32_t Offset = *reinterpret_cast<const uint32_t *>(OffsetField);
+
+    if (Offset != 0)
+      HandleFDE(CurCFIRecord);
+
+    CurCFIRecord += Size;
+    Size = *reinterpret_cast<const uint32_t *>(CurCFIRecord);
+  }
+}
+
+} // end anonymous namespace
+
+ORC_RT_INTERFACE __orc_rt_CWrapperFunctionResult
+__orc_rt_macho_register_ehframe_section(char *ArgData, size_t ArgSize) {
+  // NOTE: Does not use SPS to deserialize arg buffer, instead the arg buffer
+  // is taken to be the range of the eh-frame section.
+  bool HasError = false;
+  walkEHFrameSection(span<const char>(ArgData, ArgSize), __register_frame);
+  return __orc_rt_CreateCWrapperFunctionResultFromRange((char*)&HasError,
+                                                        sizeof(HasError));
+}
+
+ORC_RT_INTERFACE __orc_rt_CWrapperFunctionResult
+__orc_rt_macho_deregister_ehframe_section(char *ArgData, size_t ArgSize) {
+  // NOTE: Does not use SPS to deserialize arg buffer, instead the arg buffer
+  // is taken to be the range of the eh-frame section.
+  bool HasError = false;
+  walkEHFrameSection(span<const char>(ArgData, ArgSize), __deregister_frame);
+  return __orc_rt_CreateCWrapperFunctionResultFromRange((char*)&HasError,
+                                                        sizeof(HasError));
+}