File: | tools/lldb/source/Plugins/Process/Utility/StopInfoMachException.cpp |
Warning: | line 487, column 11 Value stored to 'is_actual_breakpoint' is never read |
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1 | //===-- StopInfoMachException.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 "StopInfoMachException.h" |
11 | |
12 | // C Includes |
13 | // C++ Includes |
14 | // Other libraries and framework includes |
15 | // Project includes |
16 | #include "lldb/Breakpoint/Watchpoint.h" |
17 | #include "lldb/Symbol/Symbol.h" |
18 | #include "lldb/Target/DynamicLoader.h" |
19 | #include "lldb/Target/ExecutionContext.h" |
20 | #include "lldb/Target/Process.h" |
21 | #include "lldb/Target/RegisterContext.h" |
22 | #include "lldb/Target/Target.h" |
23 | #include "lldb/Target/Thread.h" |
24 | #include "lldb/Target/ThreadPlan.h" |
25 | #include "lldb/Target/UnixSignals.h" |
26 | #include "lldb/Utility/StreamString.h" |
27 | |
28 | using namespace lldb; |
29 | using namespace lldb_private; |
30 | |
31 | const char *StopInfoMachException::GetDescription() { |
32 | if (m_description.empty() && m_value != 0) { |
33 | ExecutionContext exe_ctx(m_thread_wp.lock()); |
34 | Target *target = exe_ctx.GetTargetPtr(); |
35 | const llvm::Triple::ArchType cpu = |
36 | target ? target->GetArchitecture().GetMachine() |
37 | : llvm::Triple::UnknownArch; |
38 | |
39 | const char *exc_desc = NULL__null; |
40 | const char *code_label = "code"; |
41 | const char *code_desc = NULL__null; |
42 | const char *subcode_label = "subcode"; |
43 | const char *subcode_desc = NULL__null; |
44 | switch (m_value) { |
45 | case 1: // EXC_BAD_ACCESS |
46 | exc_desc = "EXC_BAD_ACCESS"; |
47 | subcode_label = "address"; |
48 | switch (cpu) { |
49 | case llvm::Triple::x86: |
50 | case llvm::Triple::x86_64: |
51 | switch (m_exc_code) { |
52 | case 0xd: |
53 | code_desc = "EXC_I386_GPFLT"; |
54 | m_exc_data_count = 1; |
55 | break; |
56 | } |
57 | break; |
58 | case llvm::Triple::arm: |
59 | case llvm::Triple::thumb: |
60 | switch (m_exc_code) { |
61 | case 0x101: |
62 | code_desc = "EXC_ARM_DA_ALIGN"; |
63 | break; |
64 | case 0x102: |
65 | code_desc = "EXC_ARM_DA_DEBUG"; |
66 | break; |
67 | } |
68 | break; |
69 | |
70 | case llvm::Triple::ppc: |
71 | case llvm::Triple::ppc64: |
72 | switch (m_exc_code) { |
73 | case 0x101: |
74 | code_desc = "EXC_PPC_VM_PROT_READ"; |
75 | break; |
76 | case 0x102: |
77 | code_desc = "EXC_PPC_BADSPACE"; |
78 | break; |
79 | case 0x103: |
80 | code_desc = "EXC_PPC_UNALIGNED"; |
81 | break; |
82 | } |
83 | break; |
84 | |
85 | default: |
86 | break; |
87 | } |
88 | break; |
89 | |
90 | case 2: // EXC_BAD_INSTRUCTION |
91 | exc_desc = "EXC_BAD_INSTRUCTION"; |
92 | switch (cpu) { |
93 | case llvm::Triple::x86: |
94 | case llvm::Triple::x86_64: |
95 | if (m_exc_code == 1) |
96 | code_desc = "EXC_I386_INVOP"; |
97 | break; |
98 | |
99 | case llvm::Triple::ppc: |
100 | case llvm::Triple::ppc64: |
101 | switch (m_exc_code) { |
102 | case 1: |
103 | code_desc = "EXC_PPC_INVALID_SYSCALL"; |
104 | break; |
105 | case 2: |
106 | code_desc = "EXC_PPC_UNIPL_INST"; |
107 | break; |
108 | case 3: |
109 | code_desc = "EXC_PPC_PRIVINST"; |
110 | break; |
111 | case 4: |
112 | code_desc = "EXC_PPC_PRIVREG"; |
113 | break; |
114 | case 5: |
115 | code_desc = "EXC_PPC_TRACE"; |
116 | break; |
117 | case 6: |
118 | code_desc = "EXC_PPC_PERFMON"; |
119 | break; |
120 | } |
121 | break; |
122 | |
123 | case llvm::Triple::arm: |
124 | case llvm::Triple::thumb: |
125 | if (m_exc_code == 1) |
126 | code_desc = "EXC_ARM_UNDEFINED"; |
127 | break; |
128 | |
129 | default: |
130 | break; |
131 | } |
132 | break; |
133 | |
134 | case 3: // EXC_ARITHMETIC |
135 | exc_desc = "EXC_ARITHMETIC"; |
136 | switch (cpu) { |
137 | case llvm::Triple::x86: |
138 | case llvm::Triple::x86_64: |
139 | switch (m_exc_code) { |
140 | case 1: |
141 | code_desc = "EXC_I386_DIV"; |
142 | break; |
143 | case 2: |
144 | code_desc = "EXC_I386_INTO"; |
145 | break; |
146 | case 3: |
147 | code_desc = "EXC_I386_NOEXT"; |
148 | break; |
149 | case 4: |
150 | code_desc = "EXC_I386_EXTOVR"; |
151 | break; |
152 | case 5: |
153 | code_desc = "EXC_I386_EXTERR"; |
154 | break; |
155 | case 6: |
156 | code_desc = "EXC_I386_EMERR"; |
157 | break; |
158 | case 7: |
159 | code_desc = "EXC_I386_BOUND"; |
160 | break; |
161 | case 8: |
162 | code_desc = "EXC_I386_SSEEXTERR"; |
163 | break; |
164 | } |
165 | break; |
166 | |
167 | case llvm::Triple::ppc: |
168 | case llvm::Triple::ppc64: |
169 | switch (m_exc_code) { |
170 | case 1: |
171 | code_desc = "EXC_PPC_OVERFLOW"; |
172 | break; |
173 | case 2: |
174 | code_desc = "EXC_PPC_ZERO_DIVIDE"; |
175 | break; |
176 | case 3: |
177 | code_desc = "EXC_PPC_FLT_INEXACT"; |
178 | break; |
179 | case 4: |
180 | code_desc = "EXC_PPC_FLT_ZERO_DIVIDE"; |
181 | break; |
182 | case 5: |
183 | code_desc = "EXC_PPC_FLT_UNDERFLOW"; |
184 | break; |
185 | case 6: |
186 | code_desc = "EXC_PPC_FLT_OVERFLOW"; |
187 | break; |
188 | case 7: |
189 | code_desc = "EXC_PPC_FLT_NOT_A_NUMBER"; |
190 | break; |
191 | } |
192 | break; |
193 | |
194 | default: |
195 | break; |
196 | } |
197 | break; |
198 | |
199 | case 4: // EXC_EMULATION |
200 | exc_desc = "EXC_EMULATION"; |
201 | break; |
202 | |
203 | case 5: // EXC_SOFTWARE |
204 | exc_desc = "EXC_SOFTWARE"; |
205 | if (m_exc_code == 0x10003) { |
206 | subcode_desc = "EXC_SOFT_SIGNAL"; |
207 | subcode_label = "signo"; |
208 | } |
209 | break; |
210 | |
211 | case 6: // EXC_BREAKPOINT |
212 | { |
213 | exc_desc = "EXC_BREAKPOINT"; |
214 | switch (cpu) { |
215 | case llvm::Triple::x86: |
216 | case llvm::Triple::x86_64: |
217 | switch (m_exc_code) { |
218 | case 1: |
219 | code_desc = "EXC_I386_SGL"; |
220 | break; |
221 | case 2: |
222 | code_desc = "EXC_I386_BPT"; |
223 | break; |
224 | } |
225 | break; |
226 | |
227 | case llvm::Triple::ppc: |
228 | case llvm::Triple::ppc64: |
229 | switch (m_exc_code) { |
230 | case 1: |
231 | code_desc = "EXC_PPC_BREAKPOINT"; |
232 | break; |
233 | } |
234 | break; |
235 | |
236 | case llvm::Triple::arm: |
237 | case llvm::Triple::thumb: |
238 | switch (m_exc_code) { |
239 | case 0x101: |
240 | code_desc = "EXC_ARM_DA_ALIGN"; |
241 | break; |
242 | case 0x102: |
243 | code_desc = "EXC_ARM_DA_DEBUG"; |
244 | break; |
245 | case 1: |
246 | code_desc = "EXC_ARM_BREAKPOINT"; |
247 | break; |
248 | // FIXME temporary workaround, exc_code 0 does not really mean |
249 | // EXC_ARM_BREAKPOINT |
250 | case 0: |
251 | code_desc = "EXC_ARM_BREAKPOINT"; |
252 | break; |
253 | } |
254 | break; |
255 | |
256 | default: |
257 | break; |
258 | } |
259 | } break; |
260 | |
261 | case 7: |
262 | exc_desc = "EXC_SYSCALL"; |
263 | break; |
264 | |
265 | case 8: |
266 | exc_desc = "EXC_MACH_SYSCALL"; |
267 | break; |
268 | |
269 | case 9: |
270 | exc_desc = "EXC_RPC_ALERT"; |
271 | break; |
272 | |
273 | case 10: |
274 | exc_desc = "EXC_CRASH"; |
275 | break; |
276 | case 11: |
277 | exc_desc = "EXC_RESOURCE"; |
278 | break; |
279 | case 12: |
280 | exc_desc = "EXC_GUARD"; |
281 | break; |
282 | } |
283 | |
284 | StreamString strm; |
285 | |
286 | if (exc_desc) |
287 | strm.PutCString(exc_desc); |
288 | else |
289 | strm.Printf("EXC_??? (%" PRIu64"l" "u" ")", m_value); |
290 | |
291 | if (m_exc_data_count >= 1) { |
292 | if (code_desc) |
293 | strm.Printf(" (%s=%s", code_label, code_desc); |
294 | else |
295 | strm.Printf(" (%s=%" PRIu64"l" "u", code_label, m_exc_code); |
296 | } |
297 | |
298 | if (m_exc_data_count >= 2) { |
299 | if (subcode_desc) |
300 | strm.Printf(", %s=%s", subcode_label, subcode_desc); |
301 | else |
302 | strm.Printf(", %s=0x%" PRIx64"l" "x", subcode_label, m_exc_subcode); |
303 | } |
304 | |
305 | if (m_exc_data_count > 0) |
306 | strm.PutChar(')'); |
307 | |
308 | m_description = strm.GetString(); |
309 | } |
310 | return m_description.c_str(); |
311 | } |
312 | |
313 | StopInfoSP StopInfoMachException::CreateStopReasonWithMachException( |
314 | Thread &thread, uint32_t exc_type, uint32_t exc_data_count, |
315 | uint64_t exc_code, uint64_t exc_sub_code, uint64_t exc_sub_sub_code, |
316 | bool pc_already_adjusted, bool adjust_pc_if_needed) { |
317 | if (exc_type != 0) { |
318 | uint32_t pc_decrement = 0; |
319 | ExecutionContext exe_ctx(thread.shared_from_this()); |
320 | Target *target = exe_ctx.GetTargetPtr(); |
321 | const llvm::Triple::ArchType cpu = |
322 | target ? target->GetArchitecture().GetMachine() |
323 | : llvm::Triple::UnknownArch; |
324 | |
325 | switch (exc_type) { |
326 | case 1: // EXC_BAD_ACCESS |
327 | break; |
328 | |
329 | case 2: // EXC_BAD_INSTRUCTION |
330 | switch (cpu) { |
331 | case llvm::Triple::ppc: |
332 | case llvm::Triple::ppc64: |
333 | switch (exc_code) { |
334 | case 1: // EXC_PPC_INVALID_SYSCALL |
335 | case 2: // EXC_PPC_UNIPL_INST |
336 | case 3: // EXC_PPC_PRIVINST |
337 | case 4: // EXC_PPC_PRIVREG |
338 | break; |
339 | case 5: // EXC_PPC_TRACE |
340 | return StopInfo::CreateStopReasonToTrace(thread); |
341 | case 6: // EXC_PPC_PERFMON |
342 | break; |
343 | } |
344 | break; |
345 | |
346 | default: |
347 | break; |
348 | } |
349 | break; |
350 | |
351 | case 3: // EXC_ARITHMETIC |
352 | case 4: // EXC_EMULATION |
353 | break; |
354 | |
355 | case 5: // EXC_SOFTWARE |
356 | if (exc_code == 0x10003) // EXC_SOFT_SIGNAL |
357 | { |
358 | if (exc_sub_code == 5) { |
359 | // On MacOSX, a SIGTRAP can signify that a process has called exec, |
360 | // so we should check with our dynamic loader to verify. |
361 | ProcessSP process_sp(thread.GetProcess()); |
362 | if (process_sp) { |
363 | DynamicLoader *dynamic_loader = process_sp->GetDynamicLoader(); |
364 | if (dynamic_loader && dynamic_loader->ProcessDidExec()) { |
365 | // The program was re-exec'ed |
366 | return StopInfo::CreateStopReasonWithExec(thread); |
367 | } |
368 | // if (!process_did_exec) |
369 | // { |
370 | // // We have a SIGTRAP, make sure we |
371 | // didn't exec by checking |
372 | // // for the PC being at |
373 | // "_dyld_start"... |
374 | // lldb::StackFrameSP frame_sp |
375 | // (thread.GetStackFrameAtIndex(0)); |
376 | // if (frame_sp) |
377 | // { |
378 | // const Symbol *symbol = |
379 | // frame_sp->GetSymbolContext(eSymbolContextSymbol).symbol; |
380 | // if (symbol) |
381 | // { |
382 | // if (symbol->GetName() == |
383 | // ConstString("_dyld_start")) |
384 | // process_did_exec = true; |
385 | // } |
386 | // } |
387 | // } |
388 | } |
389 | } |
390 | return StopInfo::CreateStopReasonWithSignal(thread, exc_sub_code); |
391 | } |
392 | break; |
393 | |
394 | case 6: // EXC_BREAKPOINT |
395 | { |
396 | bool is_actual_breakpoint = false; |
397 | bool is_trace_if_actual_breakpoint_missing = false; |
398 | switch (cpu) { |
399 | case llvm::Triple::x86: |
400 | case llvm::Triple::x86_64: |
401 | if (exc_code == 1) // EXC_I386_SGL |
402 | { |
403 | if (!exc_sub_code) { |
404 | // This looks like a plain trap. |
405 | // Have to check if there is a breakpoint here as well. When you |
406 | // single-step onto a trap, the single step stops you not to trap. |
407 | // Since we also do that check below, let's just use that logic. |
408 | is_actual_breakpoint = true; |
409 | is_trace_if_actual_breakpoint_missing = true; |
410 | } else { |
411 | |
412 | // It's a watchpoint, then. |
413 | // The exc_sub_code indicates the data break address. |
414 | lldb::WatchpointSP wp_sp; |
415 | if (target) |
416 | wp_sp = target->GetWatchpointList().FindByAddress( |
417 | (lldb::addr_t)exc_sub_code); |
418 | if (wp_sp && wp_sp->IsEnabled()) { |
419 | // Debugserver may piggyback the hardware index of the fired |
420 | // watchpoint in the exception data. Set the hardware index if |
421 | // that's the case. |
422 | if (exc_data_count >= 3) |
423 | wp_sp->SetHardwareIndex((uint32_t)exc_sub_sub_code); |
424 | return StopInfo::CreateStopReasonWithWatchpointID(thread, |
425 | wp_sp->GetID()); |
426 | } |
427 | } |
428 | } else if (exc_code == 2 || // EXC_I386_BPT |
429 | exc_code == 3) // EXC_I386_BPTFLT |
430 | { |
431 | // KDP returns EXC_I386_BPTFLT for trace breakpoints |
432 | if (exc_code == 3) |
433 | is_trace_if_actual_breakpoint_missing = true; |
434 | |
435 | is_actual_breakpoint = true; |
436 | if (!pc_already_adjusted) |
437 | pc_decrement = 1; |
438 | } |
439 | break; |
440 | |
441 | case llvm::Triple::ppc: |
442 | case llvm::Triple::ppc64: |
443 | is_actual_breakpoint = exc_code == 1; // EXC_PPC_BREAKPOINT |
444 | break; |
445 | |
446 | case llvm::Triple::arm: |
447 | case llvm::Triple::thumb: |
448 | if (exc_code == 0x102) // EXC_ARM_DA_DEBUG |
449 | { |
450 | // It's a watchpoint, then, if the exc_sub_code indicates a |
451 | // known/enabled data break address from our watchpoint list. |
452 | lldb::WatchpointSP wp_sp; |
453 | if (target) |
454 | wp_sp = target->GetWatchpointList().FindByAddress( |
455 | (lldb::addr_t)exc_sub_code); |
456 | if (wp_sp && wp_sp->IsEnabled()) { |
457 | // Debugserver may piggyback the hardware index of the fired |
458 | // watchpoint in the exception data. Set the hardware index if |
459 | // that's the case. |
460 | if (exc_data_count >= 3) |
461 | wp_sp->SetHardwareIndex((uint32_t)exc_sub_sub_code); |
462 | return StopInfo::CreateStopReasonWithWatchpointID(thread, |
463 | wp_sp->GetID()); |
464 | } else { |
465 | is_actual_breakpoint = true; |
466 | is_trace_if_actual_breakpoint_missing = true; |
467 | } |
468 | } else if (exc_code == 1) // EXC_ARM_BREAKPOINT |
469 | { |
470 | is_actual_breakpoint = true; |
471 | is_trace_if_actual_breakpoint_missing = true; |
472 | } else if (exc_code == 0) // FIXME not EXC_ARM_BREAKPOINT but a kernel |
473 | // is currently returning this so accept it |
474 | // as indicating a breakpoint until the |
475 | // kernel is fixed |
476 | { |
477 | is_actual_breakpoint = true; |
478 | is_trace_if_actual_breakpoint_missing = true; |
479 | } |
480 | break; |
481 | |
482 | case llvm::Triple::aarch64: { |
483 | if (exc_code == 1 && exc_sub_code == 0) // EXC_ARM_BREAKPOINT |
484 | { |
485 | // This is hit when we single instruction step aka MDSCR_EL1 SS bit 0 |
486 | // is set |
487 | is_actual_breakpoint = false; |
Value stored to 'is_actual_breakpoint' is never read | |
488 | is_trace_if_actual_breakpoint_missing = true; |
489 | } |
490 | if (exc_code == 0x102) // EXC_ARM_DA_DEBUG |
491 | { |
492 | // It's a watchpoint, then, if the exc_sub_code indicates a |
493 | // known/enabled data break address from our watchpoint list. |
494 | lldb::WatchpointSP wp_sp; |
495 | if (target) |
496 | wp_sp = target->GetWatchpointList().FindByAddress( |
497 | (lldb::addr_t)exc_sub_code); |
498 | if (wp_sp && wp_sp->IsEnabled()) { |
499 | // Debugserver may piggyback the hardware index of the fired |
500 | // watchpoint in the exception data. Set the hardware index if |
501 | // that's the case. |
502 | if (exc_data_count >= 3) |
503 | wp_sp->SetHardwareIndex((uint32_t)exc_sub_sub_code); |
504 | return StopInfo::CreateStopReasonWithWatchpointID(thread, |
505 | wp_sp->GetID()); |
506 | } |
507 | // EXC_ARM_DA_DEBUG seems to be reused for EXC_BREAKPOINT as well as |
508 | // EXC_BAD_ACCESS |
509 | if (thread.GetTemporaryResumeState() == eStateStepping) |
510 | return StopInfo::CreateStopReasonToTrace(thread); |
511 | } |
512 | // It looks like exc_sub_code has the 4 bytes of the instruction that |
513 | // triggered the exception, i.e. our breakpoint opcode |
514 | is_actual_breakpoint = exc_code == 1; |
515 | break; |
516 | } |
517 | |
518 | default: |
519 | break; |
520 | } |
521 | |
522 | if (is_actual_breakpoint) { |
523 | RegisterContextSP reg_ctx_sp(thread.GetRegisterContext()); |
524 | addr_t pc = reg_ctx_sp->GetPC() - pc_decrement; |
525 | |
526 | ProcessSP process_sp(thread.CalculateProcess()); |
527 | |
528 | lldb::BreakpointSiteSP bp_site_sp; |
529 | if (process_sp) |
530 | bp_site_sp = process_sp->GetBreakpointSiteList().FindByAddress(pc); |
531 | if (bp_site_sp && bp_site_sp->IsEnabled()) { |
532 | // Update the PC if we were asked to do so, but only do so if we find |
533 | // a breakpoint that we know about cause this could be a trap |
534 | // instruction in the code |
535 | if (pc_decrement > 0 && adjust_pc_if_needed) |
536 | reg_ctx_sp->SetPC(pc); |
537 | |
538 | // If the breakpoint is for this thread, then we'll report the hit, |
539 | // but if it is for another thread, we can just report no reason. We |
540 | // don't need to worry about stepping over the breakpoint here, that |
541 | // will be taken care of when the thread resumes and notices that |
542 | // there's a breakpoint under the pc. If we have an operating system |
543 | // plug-in, we might have set a thread specific breakpoint using the |
544 | // operating system thread ID, so we can't make any assumptions about |
545 | // the thread ID so we must always report the breakpoint regardless |
546 | // of the thread. |
547 | if (bp_site_sp->ValidForThisThread(&thread) || |
548 | thread.GetProcess()->GetOperatingSystem() != NULL__null) |
549 | return StopInfo::CreateStopReasonWithBreakpointSiteID( |
550 | thread, bp_site_sp->GetID()); |
551 | else if (is_trace_if_actual_breakpoint_missing) |
552 | return StopInfo::CreateStopReasonToTrace(thread); |
553 | else |
554 | return StopInfoSP(); |
555 | } |
556 | |
557 | // Don't call this a trace if we weren't single stepping this thread. |
558 | if (is_trace_if_actual_breakpoint_missing && |
559 | thread.GetTemporaryResumeState() == eStateStepping) { |
560 | return StopInfo::CreateStopReasonToTrace(thread); |
561 | } |
562 | } |
563 | } break; |
564 | |
565 | case 7: // EXC_SYSCALL |
566 | case 8: // EXC_MACH_SYSCALL |
567 | case 9: // EXC_RPC_ALERT |
568 | case 10: // EXC_CRASH |
569 | break; |
570 | } |
571 | |
572 | return StopInfoSP(new StopInfoMachException( |
573 | thread, exc_type, exc_data_count, exc_code, exc_sub_code)); |
574 | } |
575 | return StopInfoSP(); |
576 | } |