1 files changed, 102 insertions, 0 deletions
diff --git a/include/lldb/Target/ProcessStructReader.h b/include/lldb/Target/ProcessStructReader.h
new file mode 100644
index 000000000000..acc5c1f32686
--- /dev/null
+++ b/include/lldb/Target/ProcessStructReader.h
@@ -0,0 +1,102 @@
+//===---------------------ProcessStructReader.h ------------------*- C++-*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_TARGET_PROCESSSTRUCTREADER_H
+#define LLDB_TARGET_PROCESSSTRUCTREADER_H
+
+#include "lldb/lldb-defines.h"
+#include "lldb/lldb-types.h"
+
+#include "lldb/Symbol/CompilerType.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Utility/ConstString.h"
+#include "lldb/Utility/DataExtractor.h"
+#include "lldb/Utility/Error.h"
+
+#include <initializer_list>
+#include <map>
+#include <string>
+
+namespace lldb_private {
+class ProcessStructReader {
+protected:
+  struct FieldImpl {
+    CompilerType type;
+    size_t offset;
+    size_t size;
+  };
+
+  std::map<ConstString, FieldImpl> m_fields;
+  DataExtractor m_data;
+  lldb::ByteOrder m_byte_order;
+  size_t m_addr_byte_size;
+
+public:
+  ProcessStructReader(Process *process, lldb::addr_t base_addr,
+                      CompilerType struct_type) {
+    if (!process)
+      return;
+    if (base_addr == 0 || base_addr == LLDB_INVALID_ADDRESS)
+      return;
+    m_byte_order = process->GetByteOrder();
+    m_addr_byte_size = process->GetAddressByteSize();
+
+    for (size_t idx = 0; idx < struct_type.GetNumFields(); idx++) {
+      std::string name;
+      uint64_t bit_offset;
+      uint32_t bitfield_bit_size;
+      bool is_bitfield;
+      CompilerType field_type = struct_type.GetFieldAtIndex(
+          idx, name, &bit_offset, &bitfield_bit_size, &is_bitfield);
+      // no support for bitfields in here (yet)
+      if (is_bitfield)
+        return;
+      auto size = field_type.GetByteSize(nullptr);
+      // no support for things larger than a uint64_t (yet)
+      if (size > 8)
+        return;
+      ConstString const_name = ConstString(name.c_str());
+      size_t byte_index = static_cast<size_t>(bit_offset / 8);
+      m_fields[const_name] =
+          FieldImpl{field_type, byte_index, static_cast<size_t>(size)};
+    }
+    size_t total_size = struct_type.GetByteSize(nullptr);
+    lldb::DataBufferSP buffer_sp(new DataBufferHeap(total_size, 0));
+    Error error;
+    process->ReadMemoryFromInferior(base_addr, buffer_sp->GetBytes(),
+                                    total_size, error);
+    if (error.Fail())
+      return;
+    m_data = DataExtractor(buffer_sp, m_byte_order, m_addr_byte_size);
+  }
+
+  template <typename RetType>
+  RetType GetField(ConstString name, RetType fail_value = RetType()) {
+    auto iter = m_fields.find(name), end = m_fields.end();
+    if (iter == end)
+      return fail_value;
+    auto size = iter->second.size;
+    if (sizeof(RetType) < size)
+      return fail_value;
+    lldb::offset_t offset = iter->second.offset;
+    if (offset + size > m_data.GetByteSize())
+      return fail_value;
+    return (RetType)(m_data.GetMaxU64(&offset, size));
+  }
+
+  size_t GetOffsetOf(ConstString name, size_t fail_value = SIZE_MAX) {
+    auto iter = m_fields.find(name), end = m_fields.end();
+    if (iter == end)
+      return fail_value;
+    return iter->second.offset;
+  }
+};
+}
+
+#endif // utility_ProcessStructReader_h_