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/DataBufferHeap.h"
18 #include "lldb/Utility/DataExtractor.h"
19 #include "lldb/Utility/Status.h"
20 
21 #include "llvm/ADT/StringMap.h"
22 
23 #include <initializer_list>
24 #include <map>
25 #include <string>
26 
27 namespace lldb_private {
28 class ProcessStructReader {
29 protected:
30   struct FieldImpl {
31     CompilerType type;
32     size_t offset;
33     size_t size;
34   };
35 
36   llvm::StringMap<FieldImpl> m_fields;
37   DataExtractor m_data;
38   lldb::ByteOrder m_byte_order;
39   size_t m_addr_byte_size;
40 
41 public:
ProcessStructReader(Process * process,lldb::addr_t base_addr,CompilerType struct_type)42   ProcessStructReader(Process *process, lldb::addr_t base_addr,
43                       CompilerType struct_type)
44       : m_byte_order(lldb::eByteOrderInvalid), m_addr_byte_size(0) {
45     if (!process)
46       return;
47     if (base_addr == 0 || base_addr == LLDB_INVALID_ADDRESS)
48       return;
49     m_byte_order = process->GetByteOrder();
50     m_addr_byte_size = process->GetAddressByteSize();
51 
52     for (size_t idx = 0; idx < struct_type.GetNumFields(); idx++) {
53       std::string name;
54       uint64_t bit_offset;
55       uint32_t bitfield_bit_size;
56       bool is_bitfield;
57       CompilerType field_type = struct_type.GetFieldAtIndex(
58           idx, name, &bit_offset, &bitfield_bit_size, &is_bitfield);
59       // no support for bitfields in here (yet)
60       if (is_bitfield)
61         return;
62       auto size = field_type.GetByteSize(nullptr);
63       // no support for things larger than a uint64_t (yet)
64       if (!size || *size > 8)
65         return;
66       size_t byte_index = static_cast<size_t>(bit_offset / 8);
67       m_fields.insert({name, FieldImpl{field_type, byte_index,
68                                        static_cast<size_t>(*size)}});
69     }
70     auto total_size = struct_type.GetByteSize(nullptr);
71     if (!total_size)
72       return;
73     lldb::WritableDataBufferSP 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(llvm::StringRef 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 }
97 
98 #endif // LLDB_TARGET_PROCESSSTRUCTREADER_H
99