1 //===-- ValueObjectConstResultImpl.cpp ---------------------------*- 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 #include "lldb/Core/ValueObjectConstResultImpl.h"
10 
11 #include "lldb/Core/Value.h"
12 #include "lldb/Core/ValueObject.h"
13 #include "lldb/Core/ValueObjectConstResult.h"
14 #include "lldb/Core/ValueObjectConstResultCast.h"
15 #include "lldb/Core/ValueObjectConstResultChild.h"
16 #include "lldb/Symbol/CompilerType.h"
17 #include "lldb/Target/ExecutionContext.h"
18 #include "lldb/Utility/DataBufferHeap.h"
19 #include "lldb/Utility/Endian.h"
20 #include "lldb/Utility/Scalar.h"
21 #include "lldb/Utility/SharingPtr.h"
22 
23 #include <string>
24 
25 namespace lldb_private {
26 class DataExtractor;
27 }
28 namespace lldb_private {
29 class Status;
30 }
31 
32 using namespace lldb;
33 using namespace lldb_private;
34 
35 ValueObjectConstResultImpl::ValueObjectConstResultImpl(
36     ValueObject *valobj, lldb::addr_t live_address)
37     : m_impl_backend(valobj), m_live_address(live_address),
38       m_live_address_type(eAddressTypeLoad), m_load_addr_backend(),
39       m_address_of_backend() {}
40 
41 lldb::ValueObjectSP ValueObjectConstResultImpl::Dereference(Status &error) {
42   if (m_impl_backend == nullptr)
43     return lldb::ValueObjectSP();
44 
45   return m_impl_backend->ValueObject::Dereference(error);
46 }
47 
48 ValueObject *ValueObjectConstResultImpl::CreateChildAtIndex(
49     size_t idx, bool synthetic_array_member, int32_t synthetic_index) {
50   if (m_impl_backend == nullptr)
51     return nullptr;
52 
53   m_impl_backend->UpdateValueIfNeeded(false);
54 
55   ValueObjectConstResultChild *valobj = nullptr;
56 
57   bool omit_empty_base_classes = true;
58   bool ignore_array_bounds = synthetic_array_member;
59   std::string child_name_str;
60   uint32_t child_byte_size = 0;
61   int32_t child_byte_offset = 0;
62   uint32_t child_bitfield_bit_size = 0;
63   uint32_t child_bitfield_bit_offset = 0;
64   bool child_is_base_class = false;
65   bool child_is_deref_of_parent = false;
66   uint64_t language_flags;
67 
68   const bool transparent_pointers = !synthetic_array_member;
69   CompilerType compiler_type = m_impl_backend->GetCompilerType();
70   CompilerType child_compiler_type;
71 
72   ExecutionContext exe_ctx(m_impl_backend->GetExecutionContextRef());
73 
74   child_compiler_type = compiler_type.GetChildCompilerTypeAtIndex(
75       &exe_ctx, idx, transparent_pointers, omit_empty_base_classes,
76       ignore_array_bounds, child_name_str, child_byte_size, child_byte_offset,
77       child_bitfield_bit_size, child_bitfield_bit_offset, child_is_base_class,
78       child_is_deref_of_parent, m_impl_backend, language_flags);
79 
80   // One might think we should check that the size of the children
81   // is always strictly positive, hence we could avoid creating a
82   // ValueObject if that's not the case, but it turns out there
83   // are languages out there which allow zero-size types with
84   // children (e.g. Swift).
85   if (child_compiler_type) {
86     if (synthetic_index)
87       child_byte_offset += child_byte_size * synthetic_index;
88 
89     ConstString child_name;
90     if (!child_name_str.empty())
91       child_name.SetCString(child_name_str.c_str());
92 
93     valobj = new ValueObjectConstResultChild(
94         *m_impl_backend, child_compiler_type, child_name, child_byte_size,
95         child_byte_offset, child_bitfield_bit_size, child_bitfield_bit_offset,
96         child_is_base_class, child_is_deref_of_parent,
97         m_live_address == LLDB_INVALID_ADDRESS
98             ? m_live_address
99             : m_live_address + child_byte_offset,
100         language_flags);
101   }
102 
103   return valobj;
104 }
105 
106 lldb::ValueObjectSP ValueObjectConstResultImpl::GetSyntheticChildAtOffset(
107     uint32_t offset, const CompilerType &type, bool can_create,
108     ConstString name_const_str) {
109   if (m_impl_backend == nullptr)
110     return lldb::ValueObjectSP();
111 
112   return m_impl_backend->ValueObject::GetSyntheticChildAtOffset(
113       offset, type, can_create, name_const_str);
114 }
115 
116 lldb::ValueObjectSP ValueObjectConstResultImpl::AddressOf(Status &error) {
117   if (m_address_of_backend.get() != nullptr)
118     return m_address_of_backend;
119 
120   if (m_impl_backend == nullptr)
121     return lldb::ValueObjectSP();
122   if (m_live_address != LLDB_INVALID_ADDRESS) {
123     CompilerType compiler_type(m_impl_backend->GetCompilerType());
124 
125     lldb::DataBufferSP buffer(new lldb_private::DataBufferHeap(
126         &m_live_address, sizeof(lldb::addr_t)));
127 
128     std::string new_name("&");
129     new_name.append(m_impl_backend->GetName().AsCString(""));
130     ExecutionContext exe_ctx(m_impl_backend->GetExecutionContextRef());
131     m_address_of_backend = ValueObjectConstResult::Create(
132         exe_ctx.GetBestExecutionContextScope(), compiler_type.GetPointerType(),
133         ConstString(new_name.c_str()), buffer, endian::InlHostByteOrder(),
134         exe_ctx.GetAddressByteSize());
135 
136     m_address_of_backend->GetValue().SetValueType(Value::eValueTypeScalar);
137     m_address_of_backend->GetValue().GetScalar() = m_live_address;
138 
139     return m_address_of_backend;
140   } else
141     return m_impl_backend->ValueObject::AddressOf(error);
142 }
143 
144 lldb::ValueObjectSP
145 ValueObjectConstResultImpl::Cast(const CompilerType &compiler_type) {
146   if (m_impl_backend == nullptr)
147     return lldb::ValueObjectSP();
148 
149   ValueObjectConstResultCast *result_cast =
150       new ValueObjectConstResultCast(*m_impl_backend, m_impl_backend->GetName(),
151                                      compiler_type, m_live_address);
152   return result_cast->GetSP();
153 }
154 
155 lldb::addr_t
156 ValueObjectConstResultImpl::GetAddressOf(bool scalar_is_load_address,
157                                          AddressType *address_type) {
158 
159   if (m_impl_backend == nullptr)
160     return 0;
161 
162   if (m_live_address == LLDB_INVALID_ADDRESS) {
163     return m_impl_backend->ValueObject::GetAddressOf(scalar_is_load_address,
164                                                      address_type);
165   }
166 
167   if (address_type)
168     *address_type = m_live_address_type;
169 
170   return m_live_address;
171 }
172 
173 size_t ValueObjectConstResultImpl::GetPointeeData(DataExtractor &data,
174                                                   uint32_t item_idx,
175                                                   uint32_t item_count) {
176   if (m_impl_backend == nullptr)
177     return 0;
178   return m_impl_backend->ValueObject::GetPointeeData(data, item_idx,
179                                                      item_count);
180 }
181