ProcessStructReader.h revision 360660 
1//===---------------------ProcessStructReader.h ------------------*- C++-*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLDB_TARGET_PROCESSSTRUCTREADER_H
10#define LLDB_TARGET_PROCESSSTRUCTREADER_H
11
12#include "lldb/lldb-defines.h"
13#include "lldb/lldb-types.h"
14
15#include "lldb/Symbol/CompilerType.h"
16#include "lldb/Target/Process.h"
17#include "lldb/Utility/ConstString.h"
18#include "lldb/Utility/DataBufferHeap.h"
19#include "lldb/Utility/DataExtractor.h"
20#include "lldb/Utility/Status.h"
21
22#include <initializer_list>
23#include <map>
24#include <string>
25
26namespace lldb_private {
27class ProcessStructReader {
28protected:
29  struct FieldImpl {
30    CompilerType type;
31    size_t offset;
32    size_t size;
33  };
34
35  std::map<ConstString, FieldImpl> m_fields;
36  DataExtractor m_data;
37  lldb::ByteOrder m_byte_order;
38  size_t m_addr_byte_size;
39
40public:
41  ProcessStructReader(Process *process, lldb::addr_t base_addr,
42                      CompilerType struct_type) {
43    if (!process)
44      return;
45    if (base_addr == 0 || base_addr == LLDB_INVALID_ADDRESS)
46      return;
47    m_byte_order = process->GetByteOrder();
48    m_addr_byte_size = process->GetAddressByteSize();
49
50    for (size_t idx = 0; idx < struct_type.GetNumFields(); idx++) {
51      std::string name;
52      uint64_t bit_offset;
53      uint32_t bitfield_bit_size;
54      bool is_bitfield;
55      CompilerType field_type = struct_type.GetFieldAtIndex(
56          idx, name, &bit_offset, &bitfield_bit_size, &is_bitfield);
57      // no support for bitfields in here (yet)
58      if (is_bitfield)
59        return;
60      auto size = field_type.GetByteSize(nullptr);
61      // no support for things larger than a uint64_t (yet)
62      if (!size || *size > 8)
63        return;
64      ConstString const_name = ConstString(name.c_str());
65      size_t byte_index = static_cast<size_t>(bit_offset / 8);
66      m_fields[const_name] =
67          FieldImpl{field_type, byte_index, static_cast<size_t>(*size)};
68    }
69    auto total_size = struct_type.GetByteSize(nullptr);
70    if (!total_size)
71      return;
72    lldb::DataBufferSP buffer_sp(new DataBufferHeap(*total_size, 0));
73    Status error;
74    process->ReadMemoryFromInferior(base_addr, buffer_sp->GetBytes(),
75                                    *total_size, error);
76    if (error.Fail())
77      return;
78    m_data = DataExtractor(buffer_sp, m_byte_order, m_addr_byte_size);
79  }
80
81  template <typename RetType>
82  RetType GetField(ConstString name, RetType fail_value = RetType()) {
83    auto iter = m_fields.find(name), end = m_fields.end();
84    if (iter == end)
85      return fail_value;
86    auto size = iter->second.size;
87    if (sizeof(RetType) < size)
88      return fail_value;
89    lldb::offset_t offset = iter->second.offset;
90    if (offset + size > m_data.GetByteSize())
91      return fail_value;
92    return (RetType)(m_data.GetMaxU64(&offset, size));
93  }
94
95  size_t GetOffsetOf(ConstString name, size_t fail_value = SIZE_MAX) {
96    auto iter = m_fields.find(name), end = m_fields.end();
97    if (iter == end)
98      return fail_value;
99    return iter->second.offset;
100  }
101};
102}
103
104#endif // utility_ProcessStructReader_h_
105