1 //===-- CommandObjectDisassemble.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 "CommandObjectDisassemble.h"
10 #include "lldb/Core/AddressRange.h"
11 #include "lldb/Core/Disassembler.h"
12 #include "lldb/Core/Module.h"
13 #include "lldb/Host/OptionParser.h"
14 #include "lldb/Interpreter/CommandInterpreter.h"
15 #include "lldb/Interpreter/CommandReturnObject.h"
16 #include "lldb/Interpreter/OptionArgParser.h"
17 #include "lldb/Interpreter/Options.h"
18 #include "lldb/Symbol/Function.h"
19 #include "lldb/Symbol/Symbol.h"
20 #include "lldb/Target/SectionLoadList.h"
21 #include "lldb/Target/StackFrame.h"
22 #include "lldb/Target/Target.h"
23 
24 static constexpr unsigned default_disasm_byte_size = 32;
25 static constexpr unsigned default_disasm_num_ins = 4;
26 static constexpr unsigned large_function_threshold = 8000;
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 
31 #define LLDB_OPTIONS_disassemble
32 #include "CommandOptions.inc"
33 
34 CommandObjectDisassemble::CommandOptions::CommandOptions()
35     : Options(), num_lines_context(0), num_instructions(0), func_name(),
36       current_function(false), start_addr(), end_addr(), at_pc(false),
37       frame_line(false), plugin_name(), flavor_string(), arch(),
38       some_location_specified(false), symbol_containing_addr() {
39   OptionParsingStarting(nullptr);
40 }
41 
42 CommandObjectDisassemble::CommandOptions::~CommandOptions() = default;
43 
44 Status CommandObjectDisassemble::CommandOptions::SetOptionValue(
45     uint32_t option_idx, llvm::StringRef option_arg,
46     ExecutionContext *execution_context) {
47   Status error;
48 
49   const int short_option = m_getopt_table[option_idx].val;
50 
51   switch (short_option) {
52   case 'm':
53     show_mixed = true;
54     break;
55 
56   case 'C':
57     if (option_arg.getAsInteger(0, num_lines_context))
58       error.SetErrorStringWithFormat("invalid num context lines string: \"%s\"",
59                                      option_arg.str().c_str());
60     break;
61 
62   case 'c':
63     if (option_arg.getAsInteger(0, num_instructions))
64       error.SetErrorStringWithFormat(
65           "invalid num of instructions string: \"%s\"",
66           option_arg.str().c_str());
67     break;
68 
69   case 'b':
70     show_bytes = true;
71     break;
72 
73   case 's': {
74     start_addr = OptionArgParser::ToAddress(execution_context, option_arg,
75                                             LLDB_INVALID_ADDRESS, &error);
76     if (start_addr != LLDB_INVALID_ADDRESS)
77       some_location_specified = true;
78   } break;
79   case 'e': {
80     end_addr = OptionArgParser::ToAddress(execution_context, option_arg,
81                                           LLDB_INVALID_ADDRESS, &error);
82     if (end_addr != LLDB_INVALID_ADDRESS)
83       some_location_specified = true;
84   } break;
85 
86   case 'n':
87     func_name.assign(std::string(option_arg));
88     some_location_specified = true;
89     break;
90 
91   case 'p':
92     at_pc = true;
93     some_location_specified = true;
94     break;
95 
96   case 'l':
97     frame_line = true;
98     // Disassemble the current source line kind of implies showing mixed source
99     // code context.
100     show_mixed = true;
101     some_location_specified = true;
102     break;
103 
104   case 'P':
105     plugin_name.assign(std::string(option_arg));
106     break;
107 
108   case 'F': {
109     TargetSP target_sp =
110         execution_context ? execution_context->GetTargetSP() : TargetSP();
111     if (target_sp && (target_sp->GetArchitecture().GetTriple().getArch() ==
112                           llvm::Triple::x86 ||
113                       target_sp->GetArchitecture().GetTriple().getArch() ==
114                           llvm::Triple::x86_64)) {
115       flavor_string.assign(std::string(option_arg));
116     } else
117       error.SetErrorStringWithFormat("Disassembler flavors are currently only "
118                                      "supported for x86 and x86_64 targets.");
119     break;
120   }
121 
122   case 'r':
123     raw = true;
124     break;
125 
126   case 'f':
127     current_function = true;
128     some_location_specified = true;
129     break;
130 
131   case 'A':
132     if (execution_context) {
133       const auto &target_sp = execution_context->GetTargetSP();
134       auto platform_ptr = target_sp ? target_sp->GetPlatform().get() : nullptr;
135       arch = Platform::GetAugmentedArchSpec(platform_ptr, option_arg);
136     }
137     break;
138 
139   case 'a': {
140     symbol_containing_addr = OptionArgParser::ToAddress(
141         execution_context, option_arg, LLDB_INVALID_ADDRESS, &error);
142     if (symbol_containing_addr != LLDB_INVALID_ADDRESS) {
143       some_location_specified = true;
144     }
145   } break;
146 
147   case '\x01':
148     force = true;
149     break;
150 
151   default:
152     llvm_unreachable("Unimplemented option");
153   }
154 
155   return error;
156 }
157 
158 void CommandObjectDisassemble::CommandOptions::OptionParsingStarting(
159     ExecutionContext *execution_context) {
160   show_mixed = false;
161   show_bytes = false;
162   num_lines_context = 0;
163   num_instructions = 0;
164   func_name.clear();
165   current_function = false;
166   at_pc = false;
167   frame_line = false;
168   start_addr = LLDB_INVALID_ADDRESS;
169   end_addr = LLDB_INVALID_ADDRESS;
170   symbol_containing_addr = LLDB_INVALID_ADDRESS;
171   raw = false;
172   plugin_name.clear();
173 
174   Target *target =
175       execution_context ? execution_context->GetTargetPtr() : nullptr;
176 
177   // This is a hack till we get the ability to specify features based on
178   // architecture.  For now GetDisassemblyFlavor is really only valid for x86
179   // (and for the llvm assembler plugin, but I'm papering over that since that
180   // is the only disassembler plugin we have...
181   if (target) {
182     if (target->GetArchitecture().GetTriple().getArch() == llvm::Triple::x86 ||
183         target->GetArchitecture().GetTriple().getArch() ==
184             llvm::Triple::x86_64) {
185       flavor_string.assign(target->GetDisassemblyFlavor());
186     } else
187       flavor_string.assign("default");
188 
189   } else
190     flavor_string.assign("default");
191 
192   arch.Clear();
193   some_location_specified = false;
194   force = false;
195 }
196 
197 Status CommandObjectDisassemble::CommandOptions::OptionParsingFinished(
198     ExecutionContext *execution_context) {
199   if (!some_location_specified)
200     current_function = true;
201   return Status();
202 }
203 
204 llvm::ArrayRef<OptionDefinition>
205 CommandObjectDisassemble::CommandOptions::GetDefinitions() {
206   return llvm::makeArrayRef(g_disassemble_options);
207 }
208 
209 // CommandObjectDisassemble
210 
211 CommandObjectDisassemble::CommandObjectDisassemble(
212     CommandInterpreter &interpreter)
213     : CommandObjectParsed(
214           interpreter, "disassemble",
215           "Disassemble specified instructions in the current target.  "
216           "Defaults to the current function for the current thread and "
217           "stack frame.",
218           "disassemble [<cmd-options>]", eCommandRequiresTarget),
219       m_options() {}
220 
221 CommandObjectDisassemble::~CommandObjectDisassemble() = default;
222 
223 llvm::Error CommandObjectDisassemble::CheckRangeSize(const AddressRange &range,
224                                                      llvm::StringRef what) {
225   if (m_options.num_instructions > 0 || m_options.force ||
226       range.GetByteSize() < large_function_threshold)
227     return llvm::Error::success();
228   StreamString msg;
229   msg << "Not disassembling " << what << " because it is very large ";
230   range.Dump(&msg, &GetSelectedTarget(), Address::DumpStyleLoadAddress,
231              Address::DumpStyleFileAddress);
232   msg << ". To disassemble specify an instruction count limit, start/stop "
233          "addresses or use the --force option.";
234   return llvm::createStringError(llvm::inconvertibleErrorCode(),
235                                  msg.GetString());
236 }
237 
238 llvm::Expected<std::vector<AddressRange>>
239 CommandObjectDisassemble::GetContainingAddressRanges() {
240   std::vector<AddressRange> ranges;
241   const auto &get_range = [&](Address addr) {
242     ModuleSP module_sp(addr.GetModule());
243     SymbolContext sc;
244     bool resolve_tail_call_address = true;
245     addr.GetModule()->ResolveSymbolContextForAddress(
246         addr, eSymbolContextEverything, sc, resolve_tail_call_address);
247     if (sc.function || sc.symbol) {
248       AddressRange range;
249       sc.GetAddressRange(eSymbolContextFunction | eSymbolContextSymbol, 0,
250                          false, range);
251       ranges.push_back(range);
252     }
253   };
254 
255   Target &target = GetSelectedTarget();
256   if (!target.GetSectionLoadList().IsEmpty()) {
257     Address symbol_containing_address;
258     if (target.GetSectionLoadList().ResolveLoadAddress(
259             m_options.symbol_containing_addr, symbol_containing_address)) {
260       get_range(symbol_containing_address);
261     }
262   } else {
263     for (lldb::ModuleSP module_sp : target.GetImages().Modules()) {
264       Address file_address;
265       if (module_sp->ResolveFileAddress(m_options.symbol_containing_addr,
266                                         file_address)) {
267         get_range(file_address);
268       }
269     }
270   }
271 
272   if (ranges.empty()) {
273     return llvm::createStringError(
274         llvm::inconvertibleErrorCode(),
275         "Could not find function bounds for address 0x%" PRIx64,
276         m_options.symbol_containing_addr);
277   }
278 
279   if (llvm::Error err = CheckRangeSize(ranges[0], "the function"))
280     return std::move(err);
281   return ranges;
282 }
283 
284 llvm::Expected<std::vector<AddressRange>>
285 CommandObjectDisassemble::GetCurrentFunctionRanges() {
286   StackFrame *frame = m_exe_ctx.GetFramePtr();
287   if (!frame) {
288     return llvm::createStringError(llvm::inconvertibleErrorCode(),
289                                    "Cannot disassemble around the current "
290                                    "function without a selected frame.\n");
291   }
292   SymbolContext sc(
293       frame->GetSymbolContext(eSymbolContextFunction | eSymbolContextSymbol));
294   AddressRange range;
295   if (sc.function)
296     range = sc.function->GetAddressRange();
297   else if (sc.symbol && sc.symbol->ValueIsAddress()) {
298     range = {sc.symbol->GetAddress(), sc.symbol->GetByteSize()};
299   } else
300     range = {frame->GetFrameCodeAddress(), default_disasm_byte_size};
301 
302   if (llvm::Error err = CheckRangeSize(range, "the current function"))
303     return std::move(err);
304   return std::vector<AddressRange>{range};
305 }
306 
307 llvm::Expected<std::vector<AddressRange>>
308 CommandObjectDisassemble::GetCurrentLineRanges() {
309   StackFrame *frame = m_exe_ctx.GetFramePtr();
310   if (!frame) {
311     return llvm::createStringError(llvm::inconvertibleErrorCode(),
312                                    "Cannot disassemble around the current "
313                                    "line without a selected frame.\n");
314   }
315 
316   LineEntry pc_line_entry(
317       frame->GetSymbolContext(eSymbolContextLineEntry).line_entry);
318   if (pc_line_entry.IsValid())
319     return std::vector<AddressRange>{pc_line_entry.range};
320 
321   // No line entry, so just disassemble around the current pc
322   m_options.show_mixed = false;
323   return GetPCRanges();
324 }
325 
326 llvm::Expected<std::vector<AddressRange>>
327 CommandObjectDisassemble::GetNameRanges(CommandReturnObject &result) {
328   ConstString name(m_options.func_name.c_str());
329   const bool include_symbols = true;
330   const bool include_inlines = true;
331 
332   // Find functions matching the given name.
333   SymbolContextList sc_list;
334   GetSelectedTarget().GetImages().FindFunctions(
335       name, eFunctionNameTypeAuto, include_symbols, include_inlines, sc_list);
336 
337   std::vector<AddressRange> ranges;
338   llvm::Error range_errs = llvm::Error::success();
339   AddressRange range;
340   const uint32_t scope =
341       eSymbolContextBlock | eSymbolContextFunction | eSymbolContextSymbol;
342   const bool use_inline_block_range = true;
343   for (SymbolContext sc : sc_list.SymbolContexts()) {
344     for (uint32_t range_idx = 0;
345          sc.GetAddressRange(scope, range_idx, use_inline_block_range, range);
346          ++range_idx) {
347       if (llvm::Error err = CheckRangeSize(range, "a range"))
348         range_errs = joinErrors(std::move(range_errs), std::move(err));
349       else
350         ranges.push_back(range);
351     }
352   }
353   if (ranges.empty()) {
354     if (range_errs)
355       return std::move(range_errs);
356     return llvm::createStringError(llvm::inconvertibleErrorCode(),
357                                    "Unable to find symbol with name '%s'.\n",
358                                    name.GetCString());
359   }
360   if (range_errs)
361     result.AppendWarning(toString(std::move(range_errs)));
362   return ranges;
363 }
364 
365 llvm::Expected<std::vector<AddressRange>>
366 CommandObjectDisassemble::GetPCRanges() {
367   StackFrame *frame = m_exe_ctx.GetFramePtr();
368   if (!frame) {
369     return llvm::createStringError(llvm::inconvertibleErrorCode(),
370                                    "Cannot disassemble around the current "
371                                    "PC without a selected frame.\n");
372   }
373 
374   if (m_options.num_instructions == 0) {
375     // Disassembling at the PC always disassembles some number of
376     // instructions (not the whole function).
377     m_options.num_instructions = default_disasm_num_ins;
378   }
379   return std::vector<AddressRange>{{frame->GetFrameCodeAddress(), 0}};
380 }
381 
382 llvm::Expected<std::vector<AddressRange>>
383 CommandObjectDisassemble::GetStartEndAddressRanges() {
384   addr_t size = 0;
385   if (m_options.end_addr != LLDB_INVALID_ADDRESS) {
386     if (m_options.end_addr <= m_options.start_addr) {
387       return llvm::createStringError(llvm::inconvertibleErrorCode(),
388                                      "End address before start address.");
389     }
390     size = m_options.end_addr - m_options.start_addr;
391   }
392   return std::vector<AddressRange>{{Address(m_options.start_addr), size}};
393 }
394 
395 llvm::Expected<std::vector<AddressRange>>
396 CommandObjectDisassemble::GetRangesForSelectedMode(
397     CommandReturnObject &result) {
398   if (m_options.symbol_containing_addr != LLDB_INVALID_ADDRESS)
399     return CommandObjectDisassemble::GetContainingAddressRanges();
400   if (m_options.current_function)
401     return CommandObjectDisassemble::GetCurrentFunctionRanges();
402   if (m_options.frame_line)
403     return CommandObjectDisassemble::GetCurrentLineRanges();
404   if (!m_options.func_name.empty())
405     return CommandObjectDisassemble::GetNameRanges(result);
406   if (m_options.start_addr != LLDB_INVALID_ADDRESS)
407     return CommandObjectDisassemble::GetStartEndAddressRanges();
408   return CommandObjectDisassemble::GetPCRanges();
409 }
410 
411 bool CommandObjectDisassemble::DoExecute(Args &command,
412                                          CommandReturnObject &result) {
413   Target *target = &GetSelectedTarget();
414 
415   if (!m_options.arch.IsValid())
416     m_options.arch = target->GetArchitecture();
417 
418   if (!m_options.arch.IsValid()) {
419     result.AppendError(
420         "use the --arch option or set the target architecture to disassemble");
421     result.SetStatus(eReturnStatusFailed);
422     return false;
423   }
424 
425   const char *plugin_name = m_options.GetPluginName();
426   const char *flavor_string = m_options.GetFlavorString();
427 
428   DisassemblerSP disassembler =
429       Disassembler::FindPlugin(m_options.arch, flavor_string, plugin_name);
430 
431   if (!disassembler) {
432     if (plugin_name) {
433       result.AppendErrorWithFormat(
434           "Unable to find Disassembler plug-in named '%s' that supports the "
435           "'%s' architecture.\n",
436           plugin_name, m_options.arch.GetArchitectureName());
437     } else
438       result.AppendErrorWithFormat(
439           "Unable to find Disassembler plug-in for the '%s' architecture.\n",
440           m_options.arch.GetArchitectureName());
441     result.SetStatus(eReturnStatusFailed);
442     return false;
443   } else if (flavor_string != nullptr && !disassembler->FlavorValidForArchSpec(
444                                              m_options.arch, flavor_string))
445     result.AppendWarningWithFormat(
446         "invalid disassembler flavor \"%s\", using default.\n", flavor_string);
447 
448   result.SetStatus(eReturnStatusSuccessFinishResult);
449 
450   if (!command.empty()) {
451     result.AppendErrorWithFormat(
452         "\"disassemble\" arguments are specified as options.\n");
453     const int terminal_width =
454         GetCommandInterpreter().GetDebugger().GetTerminalWidth();
455     GetOptions()->GenerateOptionUsage(result.GetErrorStream(), this,
456                                       terminal_width);
457     result.SetStatus(eReturnStatusFailed);
458     return false;
459   }
460 
461   if (m_options.show_mixed && m_options.num_lines_context == 0)
462     m_options.num_lines_context = 2;
463 
464   // Always show the PC in the disassembly
465   uint32_t options = Disassembler::eOptionMarkPCAddress;
466 
467   // Mark the source line for the current PC only if we are doing mixed source
468   // and assembly
469   if (m_options.show_mixed)
470     options |= Disassembler::eOptionMarkPCSourceLine;
471 
472   if (m_options.show_bytes)
473     options |= Disassembler::eOptionShowBytes;
474 
475   if (m_options.raw)
476     options |= Disassembler::eOptionRawOuput;
477 
478   llvm::Expected<std::vector<AddressRange>> ranges =
479       GetRangesForSelectedMode(result);
480   if (!ranges) {
481     result.AppendError(toString(ranges.takeError()));
482     result.SetStatus(eReturnStatusFailed);
483     return result.Succeeded();
484   }
485 
486   bool print_sc_header = ranges->size() > 1;
487   for (AddressRange cur_range : *ranges) {
488     Disassembler::Limit limit;
489     if (m_options.num_instructions == 0) {
490       limit = {Disassembler::Limit::Bytes, cur_range.GetByteSize()};
491       if (limit.value == 0)
492         limit.value = default_disasm_byte_size;
493     } else {
494       limit = {Disassembler::Limit::Instructions, m_options.num_instructions};
495     }
496     if (Disassembler::Disassemble(
497             GetDebugger(), m_options.arch, plugin_name, flavor_string,
498             m_exe_ctx, cur_range.GetBaseAddress(), limit, m_options.show_mixed,
499             m_options.show_mixed ? m_options.num_lines_context : 0, options,
500             result.GetOutputStream())) {
501       result.SetStatus(eReturnStatusSuccessFinishResult);
502     } else {
503       if (m_options.symbol_containing_addr != LLDB_INVALID_ADDRESS) {
504         result.AppendErrorWithFormat(
505             "Failed to disassemble memory in function at 0x%8.8" PRIx64 ".\n",
506             m_options.symbol_containing_addr);
507       } else {
508         result.AppendErrorWithFormat(
509             "Failed to disassemble memory at 0x%8.8" PRIx64 ".\n",
510             cur_range.GetBaseAddress().GetLoadAddress(target));
511       }
512       result.SetStatus(eReturnStatusFailed);
513     }
514     if (print_sc_header)
515       result.GetOutputStream() << "\n";
516   }
517 
518   return result.Succeeded();
519 }
520