ProcessStructReader.h revision 344779 
1//===---------------------ProcessStructReader.h ------------------*- C++-*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef LLDB_TARGET_PROCESSSTRUCTREADER_H
11#define LLDB_TARGET_PROCESSSTRUCTREADER_H
12
13#include "lldb/lldb-defines.h"
14#include "lldb/lldb-types.h"
15
16#include "lldb/Symbol/CompilerType.h"
17#include "lldb/Target/Process.h"
18#include "lldb/Utility/ConstString.h"
19#include "lldb/Utility/DataBufferHeap.h"
20#include "lldb/Utility/DataExtractor.h"
21#include "lldb/Utility/Status.h"
22
23#include <initializer_list>
24#include <map>
25#include <string>
26
27namespace lldb_private {
28class ProcessStructReader {
29protected:
30  struct FieldImpl {
31    CompilerType type;
32    size_t offset;
33    size_t size;
34  };
35
36  std::map<ConstString, FieldImpl> m_fields;
37  DataExtractor m_data;
38  lldb::ByteOrder m_byte_order;
39  size_t m_addr_byte_size;
40
41public:
42  ProcessStructReader(Process *process, lldb::addr_t base_addr,
43                      CompilerType struct_type) {
44    if (!process)
45      return;
46    if (base_addr == 0 || base_addr == LLDB_INVALID_ADDRESS)
47      return;
48    m_byte_order = process->GetByteOrder();
49    m_addr_byte_size = process->GetAddressByteSize();
50
51    for (size_t idx = 0; idx < struct_type.GetNumFields(); idx++) {
52      std::string name;
53      uint64_t bit_offset;
54      uint32_t bitfield_bit_size;
55      bool is_bitfield;
56      CompilerType field_type = struct_type.GetFieldAtIndex(
57          idx, name, &bit_offset, &bitfield_bit_size, &is_bitfield);
58      // no support for bitfields in here (yet)
59      if (is_bitfield)
60        return;
61      auto size = field_type.GetByteSize(nullptr);
62      // no support for things larger than a uint64_t (yet)
63      if (!size || *size > 8)
64        return;
65      ConstString const_name = ConstString(name.c_str());
66      size_t byte_index = static_cast<size_t>(bit_offset / 8);
67      m_fields[const_name] =
68          FieldImpl{field_type, byte_index, static_cast<size_t>(*size)};
69    }
70    auto total_size = struct_type.GetByteSize(nullptr);
71    if (!total_size)
72      return;
73    lldb::DataBufferSP buffer_sp(new DataBufferHeap(*total_size, 0));
74    Status error;
75    process->ReadMemoryFromInferior(base_addr, buffer_sp->GetBytes(),
76                                    *total_size, error);
77    if (error.Fail())
78      return;
79    m_data = DataExtractor(buffer_sp, m_byte_order, m_addr_byte_size);
80  }
81
82  template <typename RetType>
83  RetType GetField(ConstString name, RetType fail_value = RetType()) {
84    auto iter = m_fields.find(name), end = m_fields.end();
85    if (iter == end)
86      return fail_value;
87    auto size = iter->second.size;
88    if (sizeof(RetType) < size)
89      return fail_value;
90    lldb::offset_t offset = iter->second.offset;
91    if (offset + size > m_data.GetByteSize())
92      return fail_value;
93    return (RetType)(m_data.GetMaxU64(&offset, size));
94  }
95
96  size_t GetOffsetOf(ConstString name, size_t fail_value = SIZE_MAX) {
97    auto iter = m_fields.find(name), end = m_fields.end();
98    if (iter == end)
99      return fail_value;
100    return iter->second.offset;
101  }
102};
103}
104
105#endif // utility_ProcessStructReader_h_
106