1//===-- DumpRegisterValue.cpp ---------------------------------------------===//
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/DumpRegisterValue.h"
10#include "lldb/Core/DumpDataExtractor.h"
11#include "lldb/Core/ValueObject.h"
12#include "lldb/Core/ValueObjectConstResult.h"
13#include "lldb/DataFormatters/DumpValueObjectOptions.h"
14#include "lldb/Target/RegisterFlags.h"
15#include "lldb/Utility/DataExtractor.h"
16#include "lldb/Utility/Endian.h"
17#include "lldb/Utility/RegisterValue.h"
18#include "lldb/Utility/StreamString.h"
19#include "lldb/lldb-private-types.h"
20#include "llvm/ADT/bit.h"
21
22using namespace lldb;
23
24template <typename T>
25static void dump_type_value(lldb_private::CompilerType &fields_type, T value,
26 lldb_private::ExecutionContextScope *exe_scope,
27 const lldb_private::RegisterInfo &reg_info,
28 lldb_private::Stream &strm) {
29 lldb::ByteOrder target_order = exe_scope->CalculateProcess()->GetByteOrder();
30
31 // For the bitfield types we generate, it is expected that the fields are
32 // in what is usually a big endian order. Most significant field first.
33 // This is also clang's internal ordering and the order we want to print
34 // them. On a big endian host this all matches up, for a little endian
35 // host we have to swap the order of the fields before display.
36 if (target_order == lldb::ByteOrder::eByteOrderLittle) {
37 value = reg_info.flags_type->ReverseFieldOrder(value);
38 }
39
40 // Then we need to match the target's endian on a byte level as well.
41 if (lldb_private::endian::InlHostByteOrder() != target_order)
42 value = llvm::byteswap(value);
43
44 lldb_private::DataExtractor data_extractor{
45 &value, sizeof(T), lldb_private::endian::InlHostByteOrder(), 8};
46
47 lldb::ValueObjectSP vobj_sp = lldb_private::ValueObjectConstResult::Create(
48 exe_scope, compiler_type: fields_type, name: lldb_private::ConstString(), data: data_extractor);
49 lldb_private::DumpValueObjectOptions dump_options;
50 lldb_private::DumpValueObjectOptions::ChildPrintingDecider decider =
51 [](lldb_private::ConstString varname) {
52 // Unnamed bit-fields are padding that we don't want to show.
53 return varname.GetLength();
54 };
55 dump_options.SetChildPrintingDecider(decider).SetHideRootType(true);
56
57 vobj_sp->Dump(s&: strm, options: dump_options);
58}
59
60void lldb_private::DumpRegisterValue(const RegisterValue &reg_val, Stream &s,
61 const RegisterInfo &reg_info,
62 bool prefix_with_name,
63 bool prefix_with_alt_name, Format format,
64 uint32_t reg_name_right_align_at,
65 ExecutionContextScope *exe_scope,
66 bool print_flags, TargetSP target_sp) {
67 DataExtractor data;
68 if (!reg_val.GetData(data))
69 return;
70
71 bool name_printed = false;
72 // For simplicity, alignment of the register name printing applies only in
73 // the most common case where:
74 //
75 // prefix_with_name^prefix_with_alt_name is true
76 //
77 StreamString format_string;
78 if (reg_name_right_align_at && (prefix_with_name ^ prefix_with_alt_name))
79 format_string.Printf(format: "%%%us", reg_name_right_align_at);
80 else
81 format_string.Printf(format: "%%s");
82 std::string fmt = std::string(format_string.GetString());
83 if (prefix_with_name) {
84 if (reg_info.name) {
85 s.Printf(format: fmt.c_str(), reg_info.name);
86 name_printed = true;
87 } else if (reg_info.alt_name) {
88 s.Printf(format: fmt.c_str(), reg_info.alt_name);
89 prefix_with_alt_name = false;
90 name_printed = true;
91 }
92 }
93 if (prefix_with_alt_name) {
94 if (name_printed)
95 s.PutChar(ch: '/');
96 if (reg_info.alt_name) {
97 s.Printf(format: fmt.c_str(), reg_info.alt_name);
98 name_printed = true;
99 } else if (!name_printed) {
100 // No alternate name but we were asked to display a name, so show the
101 // main name
102 s.Printf(format: fmt.c_str(), reg_info.name);
103 name_printed = true;
104 }
105 }
106 if (name_printed)
107 s.PutCString(cstr: " = ");
108
109 if (format == eFormatDefault)
110 format = reg_info.format;
111
112 DumpDataExtractor(DE: data, s: &s,
113 offset: 0, // Offset in "data"
114 item_format: format, // Format to use when dumping
115 item_byte_size: reg_info.byte_size, // item_byte_size
116 item_count: 1, // item_count
117 UINT32_MAX, // num_per_line
118 LLDB_INVALID_ADDRESS, // base_addr
119 item_bit_size: 0, // item_bit_size
120 item_bit_offset: 0, // item_bit_offset
121 exe_scope);
122
123 if (!print_flags || !reg_info.flags_type || !exe_scope || !target_sp ||
124 (reg_info.byte_size != 4 && reg_info.byte_size != 8))
125 return;
126
127 CompilerType fields_type = target_sp->GetRegisterType(
128 name: reg_info.name, flags: *reg_info.flags_type, byte_size: reg_info.byte_size);
129
130 // Use a new stream so we can remove a trailing newline later.
131 StreamString fields_stream;
132
133 if (reg_info.byte_size == 4) {
134 dump_type_value(fields_type, value: reg_val.GetAsUInt32(), exe_scope, reg_info,
135 strm&: fields_stream);
136 } else {
137 dump_type_value(fields_type, value: reg_val.GetAsUInt64(), exe_scope, reg_info,
138 strm&: fields_stream);
139 }
140
141 // Registers are indented like:
142 // (lldb) register read foo
143 // foo = 0x12345678
144 // So we need to indent to match that.
145
146 // First drop the extra newline that the value printer added. The register
147 // command will add one itself.
148 llvm::StringRef fields_str = fields_stream.GetString().drop_back();
149
150 // End the line that contains " foo = 0x12345678".
151 s.EOL();
152
153 // Then split the value lines and indent each one.
154 bool first = true;
155 while (fields_str.size()) {
156 std::pair<llvm::StringRef, llvm::StringRef> split = fields_str.split(Separator: '\n');
157 fields_str = split.second;
158 // Indent as far as the register name did.
159 s.Printf(format: fmt.c_str(), "");
160
161 // Lines after the first won't have " = " so compensate for that.
162 if (!first)
163 s << " ";
164 first = false;
165
166 s << split.first;
167
168 // On the last line we don't want a newline because the command will add
169 // one too.
170 if (fields_str.size())
171 s.EOL();
172 }
173}
174

source code of lldb/source/Core/DumpRegisterValue.cpp