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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 
26 namespace lldb_private {
27 class ProcessStructReader {
28 protected:
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 
40 public:
ProcessStructReader(Process * process,lldb::addr_t base_addr,CompilerType struct_type)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 // LLDB_TARGET_PROCESSSTRUCTREADER_H
105