Bug Summary

File:tools/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp
Warning:line 221, column 5
Value stored to 'isDwarf64' is never read

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name DWARFDebugRanges.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -mrelocation-model pic -pic-level 2 -mthread-model posix -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -momit-leaf-frame-pointer -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-8/lib/clang/8.0.0 -D HAVE_ROUND -D LLDB_CONFIGURATION_RELEASE -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/lldb/source/Plugins/SymbolFile/DWARF -I /build/llvm-toolchain-snapshot-8~svn345461/tools/lldb/source/Plugins/SymbolFile/DWARF -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/lldb/include -I /build/llvm-toolchain-snapshot-8~svn345461/tools/lldb/include -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/include -I /build/llvm-toolchain-snapshot-8~svn345461/include -I /usr/include/python2.7 -I /build/llvm-toolchain-snapshot-8~svn345461/tools/clang/include -I /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/lldb/../clang/include -I /build/llvm-toolchain-snapshot-8~svn345461/tools/lldb/source/. -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/include/clang/8.0.0/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-8/lib/clang/8.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -Wno-deprecated-declarations -Wno-unknown-pragmas -Wno-strict-aliasing -Wno-deprecated-register -Wno-vla-extension -std=c++11 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-8~svn345461/build-llvm/tools/lldb/source/Plugins/SymbolFile/DWARF -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -o /tmp/scan-build-2018-10-27-211344-32123-1 -x c++ /build/llvm-toolchain-snapshot-8~svn345461/tools/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp -faddrsig
1//===-- DWARFDebugRanges.cpp ------------------------------------*- 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#include "DWARFDebugRanges.h"
11#include "DWARFUnit.h"
12#include "SymbolFileDWARF.h"
13#include "lldb/Utility/Stream.h"
14#include <assert.h>
15
16using namespace lldb_private;
17using namespace std;
18
19static dw_addr_t GetBaseAddressMarker(uint32_t addr_size) {
20 switch(addr_size) {
21 case 2:
22 return 0xffff;
23 case 4:
24 return 0xffffffff;
25 case 8:
26 return 0xffffffffffffffff;
27 }
28 llvm_unreachable("GetBaseAddressMarker unsupported address size.")::llvm::llvm_unreachable_internal("GetBaseAddressMarker unsupported address size."
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp"
, 28);
29}
30
31DWARFDebugRanges::DWARFDebugRanges() : m_range_map() {}
32
33void DWARFDebugRanges::Extract(SymbolFileDWARF *dwarf2Data) {
34 DWARFRangeList range_list;
35 lldb::offset_t offset = 0;
36 dw_offset_t debug_ranges_offset = offset;
37 while (Extract(dwarf2Data, &offset, range_list)) {
38 range_list.Sort();
39 m_range_map[debug_ranges_offset] = range_list;
40 debug_ranges_offset = offset;
41 }
42}
43
44bool DWARFDebugRanges::Extract(SymbolFileDWARF *dwarf2Data,
45 lldb::offset_t *offset_ptr,
46 DWARFRangeList &range_list) {
47 range_list.Clear();
48
49 lldb::offset_t range_offset = *offset_ptr;
50 const DWARFDataExtractor &debug_ranges_data =
51 dwarf2Data->get_debug_ranges_data();
52 uint32_t addr_size = debug_ranges_data.GetAddressByteSize();
53 dw_addr_t base_addr = 0;
54 dw_addr_t base_addr_marker = GetBaseAddressMarker(addr_size);
55
56 while (
57 debug_ranges_data.ValidOffsetForDataOfSize(*offset_ptr, 2 * addr_size)) {
58 dw_addr_t begin = debug_ranges_data.GetMaxU64(offset_ptr, addr_size);
59 dw_addr_t end = debug_ranges_data.GetMaxU64(offset_ptr, addr_size);
60
61 if (!begin && !end) {
62 // End of range list
63 break;
64 }
65
66 if (begin == base_addr_marker) {
67 base_addr = end;
68 continue;
69 }
70
71 // Filter out empty ranges
72 if (begin < end)
73 range_list.Append(DWARFRangeList::Entry(begin + base_addr, end - begin));
74 }
75
76 // Make sure we consumed at least something
77 return range_offset != *offset_ptr;
78}
79
80void DWARFDebugRanges::Dump(Stream &s,
81 const DWARFDataExtractor &debug_ranges_data,
82 lldb::offset_t *offset_ptr,
83 dw_addr_t cu_base_addr) {
84 uint32_t addr_size = s.GetAddressByteSize();
85
86 dw_addr_t base_addr = cu_base_addr;
87 while (
88 debug_ranges_data.ValidOffsetForDataOfSize(*offset_ptr, 2 * addr_size)) {
89 dw_addr_t begin = debug_ranges_data.GetMaxU64(offset_ptr, addr_size);
90 dw_addr_t end = debug_ranges_data.GetMaxU64(offset_ptr, addr_size);
91 // Extend 4 byte addresses that consists of 32 bits of 1's to be 64 bits of
92 // ones
93 if (begin == 0xFFFFFFFFull && addr_size == 4)
94 begin = LLDB_INVALID_ADDRESS(18446744073709551615UL);
95
96 s.Indent();
97 if (begin == 0 && end == 0) {
98 s.PutCString(" End");
99 break;
100 } else if (begin == LLDB_INVALID_ADDRESS(18446744073709551615UL)) {
101 // A base address selection entry
102 base_addr = end;
103 s.Address(base_addr, sizeof(dw_addr_t), " Base address = ");
104 } else {
105 // Convert from offset to an address
106 dw_addr_t begin_addr = begin + base_addr;
107 dw_addr_t end_addr = end + base_addr;
108
109 s.AddressRange(begin_addr, end_addr, sizeof(dw_addr_t), NULL__null);
110 }
111 }
112}
113
114bool DWARFDebugRanges::FindRanges(const DWARFUnit *cu,
115 dw_offset_t debug_ranges_offset,
116 DWARFRangeList &range_list) const {
117 dw_addr_t debug_ranges_address = cu->GetRangesBase() + debug_ranges_offset;
118 range_map_const_iterator pos = m_range_map.find(debug_ranges_address);
119 if (pos != m_range_map.end()) {
120 range_list = pos->second;
121
122 // All DW_AT_ranges are relative to the base address of the compile
123 // unit. We add the compile unit base address to make sure all the
124 // addresses are properly fixed up.
125 range_list.Slide(cu->GetBaseAddress());
126 return true;
127 }
128 return false;
129}
130
131bool DWARFDebugRngLists::ExtractRangeList(
132 const DWARFDataExtractor &data, uint8_t addrSize,
133 lldb::offset_t *offset_ptr, std::vector<RngListEntry> &rangeList) {
134 rangeList.clear();
135
136 bool error = false;
137 while (!error) {
138 switch (data.GetU8(offset_ptr)) {
139 case DW_RLE_end_of_list:
140 return true;
141
142 case DW_RLE_start_length: {
143 dw_addr_t begin = data.GetMaxU64(offset_ptr, addrSize);
144 dw_addr_t len = data.GetULEB128(offset_ptr);
145 rangeList.push_back({DW_RLE_start_length, begin, len});
146 break;
147 }
148
149 case DW_RLE_start_end: {
150 dw_addr_t begin = data.GetMaxU64(offset_ptr, addrSize);
151 dw_addr_t end = data.GetMaxU64(offset_ptr, addrSize);
152 rangeList.push_back({DW_RLE_start_end, begin, end});
153 break;
154 }
155
156 case DW_RLE_base_address: {
157 dw_addr_t base = data.GetMaxU64(offset_ptr, addrSize);
158 rangeList.push_back({DW_RLE_base_address, base, 0});
159 break;
160 }
161
162 case DW_RLE_offset_pair: {
163 dw_addr_t begin = data.GetULEB128(offset_ptr);
164 dw_addr_t end = data.GetULEB128(offset_ptr);
165 rangeList.push_back({DW_RLE_offset_pair, begin, end});
166 break;
167 }
168
169 default:
170 // Next encodings are not yet supported:
171 // DW_RLE_base_addressx, DW_RLE_startx_endx, DW_RLE_startx_length,
172 // DW_RLE_offset_pair, DW_RLE_base_address.
173 lldbassert(0 && "unknown range list entry encoding")lldb_private::lldb_assert(static_cast<bool>(0 &&
"unknown range list entry encoding"), "0 && \"unknown range list entry encoding\""
, __FUNCTION__, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp"
, 173);
174 error = true;
175 }
176 }
177
178 return false;
179}
180
181bool DWARFDebugRngLists::FindRanges(const DWARFUnit *cu,
182 dw_offset_t debug_ranges_offset,
183 DWARFRangeList &range_list) const {
184 range_list.Clear();
185 dw_addr_t debug_ranges_address = cu->GetRangesBase() + debug_ranges_offset;
186 auto pos = m_range_map.find(debug_ranges_address);
187 if (pos != m_range_map.end()) {
188 dw_addr_t BaseAddr = cu->GetBaseAddress();
189 for (const RngListEntry &E : pos->second) {
190 switch (E.encoding) {
191 case DW_RLE_start_length:
192 range_list.Append(DWARFRangeList::Entry(E.value0, E.value1));
193 break;
194 case DW_RLE_base_address:
195 BaseAddr = E.value0;
196 break;
197 case DW_RLE_start_end:
198 range_list.Append(DWARFRangeList::Entry(E.value0, E.value1 - E.value0));
199 break;
200 case DW_RLE_offset_pair:
201 range_list.Append(
202 DWARFRangeList::Entry(BaseAddr + E.value0, E.value1 - E.value0));
203 break;
204 default:
205 llvm_unreachable("unexpected encoding")::llvm::llvm_unreachable_internal("unexpected encoding", "/build/llvm-toolchain-snapshot-8~svn345461/tools/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp"
, 205);
206 }
207 }
208 return true;
209 }
210 return false;
211}
212
213void DWARFDebugRngLists::Extract(SymbolFileDWARF *dwarf2Data) {
214 const DWARFDataExtractor &data = dwarf2Data->get_debug_rnglists_data();
215 lldb::offset_t offset = 0;
216
217 uint64_t length = data.GetU32(&offset);
218 bool isDwarf64 = false;
219 if (length == 0xffffffff) {
220 length = data.GetU64(&offset);
221 isDwarf64 = true;
Value stored to 'isDwarf64' is never read
222 }
223 lldb::offset_t end = offset + length;
224
225 // Check version.
226 if (data.GetU16(&offset) < 5)
227 return;
228
229 uint8_t addrSize = data.GetU8(&offset);
230
231 // We do not support non-zero segment selector size.
232 if (data.GetU8(&offset) != 0) {
233 lldbassert(0 && "not implemented")lldb_private::lldb_assert(static_cast<bool>(0 &&
"not implemented"), "0 && \"not implemented\"", __FUNCTION__
, "/build/llvm-toolchain-snapshot-8~svn345461/tools/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp"
, 233);
234 return;
235 }
236
237 uint32_t offsetsAmount = data.GetU32(&offset);
238 for (uint32_t i = 0; i < offsetsAmount; ++i)
239 Offsets.push_back(data.GetPointer(&offset));
240
241 lldb::offset_t listOffset = offset;
242 std::vector<RngListEntry> rangeList;
243 while (offset < end && ExtractRangeList(data, addrSize, &offset, rangeList)) {
244 m_range_map[listOffset] = rangeList;
245 listOffset = offset;
246 }
247}