1 /*
2  * Copyright (C) 2014 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "graph_checker.h"
18 
19 #include <algorithm>
20 #include <sstream>
21 #include <string>
22 
23 #include "android-base/stringprintf.h"
24 
25 #include "base/bit_vector-inl.h"
26 #include "base/scoped_arena_allocator.h"
27 #include "base/scoped_arena_containers.h"
28 #include "code_generator.h"
29 #include "handle.h"
30 #include "mirror/class.h"
31 #include "obj_ptr-inl.h"
32 #include "scoped_thread_state_change-inl.h"
33 #include "subtype_check.h"
34 
35 namespace art {
36 
37 using android::base::StringPrintf;
38 
IsAllowedToJumpToExitBlock(HInstruction * instruction)39 static bool IsAllowedToJumpToExitBlock(HInstruction* instruction) {
40   // Anything that returns is allowed to jump into the exit block.
41   if (instruction->IsReturn() || instruction->IsReturnVoid()) {
42     return true;
43   }
44   // Anything that always throws is allowed to jump into the exit block.
45   if (instruction->IsGoto() && instruction->GetPrevious() != nullptr) {
46     instruction = instruction->GetPrevious();
47   }
48   return instruction->AlwaysThrows();
49 }
50 
IsExitTryBoundaryIntoExitBlock(HBasicBlock * block)51 static bool IsExitTryBoundaryIntoExitBlock(HBasicBlock* block) {
52   if (!block->IsSingleTryBoundary()) {
53     return false;
54   }
55 
56   HTryBoundary* boundary = block->GetLastInstruction()->AsTryBoundary();
57   return block->GetPredecessors().size() == 1u &&
58          boundary->GetNormalFlowSuccessor()->IsExitBlock() &&
59          !boundary->IsEntry();
60 }
61 
62 
Run(bool pass_change,size_t last_size)63 size_t GraphChecker::Run(bool pass_change, size_t last_size) {
64   size_t current_size = GetGraph()->GetReversePostOrder().size();
65   if (!pass_change) {
66     // Nothing changed for certain. Do a quick check of the validity on that assertion
67     // for anything other than the first call (when last size was still 0).
68     if (last_size != 0) {
69       if (current_size != last_size) {
70         AddError(StringPrintf("Incorrect no-change assertion, "
71                               "last graph size %zu vs current graph size %zu",
72                               last_size, current_size));
73       }
74     }
75     // TODO: if we would trust the "false" value of the flag completely, we
76     // could skip checking the graph at this point.
77   }
78 
79   // VisitReversePostOrder is used instead of VisitInsertionOrder,
80   // as the latter might visit dead blocks removed by the dominator
81   // computation.
82   VisitReversePostOrder();
83   return current_size;
84 }
85 
VisitBasicBlock(HBasicBlock * block)86 void GraphChecker::VisitBasicBlock(HBasicBlock* block) {
87   current_block_ = block;
88 
89   // Use local allocator for allocating memory.
90   ScopedArenaAllocator allocator(GetGraph()->GetArenaStack());
91 
92   // Check consistency with respect to predecessors of `block`.
93   // Note: Counting duplicates with a sorted vector uses up to 6x less memory
94   // than ArenaSafeMap<HBasicBlock*, size_t> and also allows storage reuse.
95   ScopedArenaVector<HBasicBlock*> sorted_predecessors(allocator.Adapter(kArenaAllocGraphChecker));
96   sorted_predecessors.assign(block->GetPredecessors().begin(), block->GetPredecessors().end());
97   std::sort(sorted_predecessors.begin(), sorted_predecessors.end());
98   for (auto it = sorted_predecessors.begin(), end = sorted_predecessors.end(); it != end; ) {
99     HBasicBlock* p = *it++;
100     size_t p_count_in_block_predecessors = 1u;
101     for (; it != end && *it == p; ++it) {
102       ++p_count_in_block_predecessors;
103     }
104     size_t block_count_in_p_successors =
105         std::count(p->GetSuccessors().begin(), p->GetSuccessors().end(), block);
106     if (p_count_in_block_predecessors != block_count_in_p_successors) {
107       AddError(StringPrintf(
108           "Block %d lists %zu occurrences of block %d in its predecessors, whereas "
109           "block %d lists %zu occurrences of block %d in its successors.",
110           block->GetBlockId(), p_count_in_block_predecessors, p->GetBlockId(),
111           p->GetBlockId(), block_count_in_p_successors, block->GetBlockId()));
112     }
113   }
114 
115   // Check consistency with respect to successors of `block`.
116   // Note: Counting duplicates with a sorted vector uses up to 6x less memory
117   // than ArenaSafeMap<HBasicBlock*, size_t> and also allows storage reuse.
118   ScopedArenaVector<HBasicBlock*> sorted_successors(allocator.Adapter(kArenaAllocGraphChecker));
119   sorted_successors.assign(block->GetSuccessors().begin(), block->GetSuccessors().end());
120   std::sort(sorted_successors.begin(), sorted_successors.end());
121   for (auto it = sorted_successors.begin(), end = sorted_successors.end(); it != end; ) {
122     HBasicBlock* s = *it++;
123     size_t s_count_in_block_successors = 1u;
124     for (; it != end && *it == s; ++it) {
125       ++s_count_in_block_successors;
126     }
127     size_t block_count_in_s_predecessors =
128         std::count(s->GetPredecessors().begin(), s->GetPredecessors().end(), block);
129     if (s_count_in_block_successors != block_count_in_s_predecessors) {
130       AddError(StringPrintf(
131           "Block %d lists %zu occurrences of block %d in its successors, whereas "
132           "block %d lists %zu occurrences of block %d in its predecessors.",
133           block->GetBlockId(), s_count_in_block_successors, s->GetBlockId(),
134           s->GetBlockId(), block_count_in_s_predecessors, block->GetBlockId()));
135     }
136   }
137 
138   // Ensure `block` ends with a branch instruction.
139   // This invariant is not enforced on non-SSA graphs. Graph built from DEX with
140   // dead code that falls out of the method will not end with a control-flow
141   // instruction. Such code is removed during the SSA-building DCE phase.
142   if (GetGraph()->IsInSsaForm() && !block->EndsWithControlFlowInstruction()) {
143     AddError(StringPrintf("Block %d does not end with a branch instruction.",
144                           block->GetBlockId()));
145   }
146 
147   // Ensure that only Return(Void) and Throw jump to Exit. An exiting TryBoundary
148   // may be between the instructions if the Throw/Return(Void) is in a try block.
149   if (block->IsExitBlock()) {
150     for (HBasicBlock* predecessor : block->GetPredecessors()) {
151       HInstruction* last_instruction = IsExitTryBoundaryIntoExitBlock(predecessor) ?
152         predecessor->GetSinglePredecessor()->GetLastInstruction() :
153         predecessor->GetLastInstruction();
154       if (!IsAllowedToJumpToExitBlock(last_instruction)) {
155         AddError(StringPrintf("Unexpected instruction %s:%d jumps into the exit block.",
156                               last_instruction->DebugName(),
157                               last_instruction->GetId()));
158       }
159     }
160   }
161 
162   // Visit this block's list of phis.
163   for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
164     HInstruction* current = it.Current();
165     // Ensure this block's list of phis contains only phis.
166     if (!current->IsPhi()) {
167       AddError(StringPrintf("Block %d has a non-phi in its phi list.",
168                             current_block_->GetBlockId()));
169     }
170     if (current->GetNext() == nullptr && current != block->GetLastPhi()) {
171       AddError(StringPrintf("The recorded last phi of block %d does not match "
172                             "the actual last phi %d.",
173                             current_block_->GetBlockId(),
174                             current->GetId()));
175     }
176     current->Accept(this);
177   }
178 
179   // Visit this block's list of instructions.
180   for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
181     HInstruction* current = it.Current();
182     // Ensure this block's list of instructions does not contains phis.
183     if (current->IsPhi()) {
184       AddError(StringPrintf("Block %d has a phi in its non-phi list.",
185                             current_block_->GetBlockId()));
186     }
187     if (current->GetNext() == nullptr && current != block->GetLastInstruction()) {
188       AddError(StringPrintf("The recorded last instruction of block %d does not match "
189                             "the actual last instruction %d.",
190                             current_block_->GetBlockId(),
191                             current->GetId()));
192     }
193     current->Accept(this);
194   }
195 
196   // Ensure that catch blocks are not normal successors, and normal blocks are
197   // never exceptional successors.
198   for (HBasicBlock* successor : block->GetNormalSuccessors()) {
199     if (successor->IsCatchBlock()) {
200       AddError(StringPrintf("Catch block %d is a normal successor of block %d.",
201                             successor->GetBlockId(),
202                             block->GetBlockId()));
203     }
204   }
205   for (HBasicBlock* successor : block->GetExceptionalSuccessors()) {
206     if (!successor->IsCatchBlock()) {
207       AddError(StringPrintf("Normal block %d is an exceptional successor of block %d.",
208                             successor->GetBlockId(),
209                             block->GetBlockId()));
210     }
211   }
212 
213   // Ensure dominated blocks have `block` as the dominator.
214   for (HBasicBlock* dominated : block->GetDominatedBlocks()) {
215     if (dominated->GetDominator() != block) {
216       AddError(StringPrintf("Block %d should be the dominator of %d.",
217                             block->GetBlockId(),
218                             dominated->GetBlockId()));
219     }
220   }
221 
222   // Ensure there is no critical edge (i.e., an edge connecting a
223   // block with multiple successors to a block with multiple
224   // predecessors). Exceptional edges are synthesized and hence
225   // not accounted for.
226   if (block->GetSuccessors().size() > 1) {
227     if (IsExitTryBoundaryIntoExitBlock(block)) {
228       // Allowed critical edge (Throw/Return/ReturnVoid)->TryBoundary->Exit.
229     } else {
230       for (HBasicBlock* successor : block->GetNormalSuccessors()) {
231         if (successor->GetPredecessors().size() > 1) {
232           AddError(StringPrintf("Critical edge between blocks %d and %d.",
233                                 block->GetBlockId(),
234                                 successor->GetBlockId()));
235         }
236       }
237     }
238   }
239 
240   // Ensure try membership information is consistent.
241   if (block->IsCatchBlock()) {
242     if (block->IsTryBlock()) {
243       const HTryBoundary& try_entry = block->GetTryCatchInformation()->GetTryEntry();
244       AddError(StringPrintf("Catch blocks should not be try blocks but catch block %d "
245                             "has try entry %s:%d.",
246                             block->GetBlockId(),
247                             try_entry.DebugName(),
248                             try_entry.GetId()));
249     }
250 
251     if (block->IsLoopHeader()) {
252       AddError(StringPrintf("Catch blocks should not be loop headers but catch block %d is.",
253                             block->GetBlockId()));
254     }
255   } else {
256     for (HBasicBlock* predecessor : block->GetPredecessors()) {
257       const HTryBoundary* incoming_try_entry = predecessor->ComputeTryEntryOfSuccessors();
258       if (block->IsTryBlock()) {
259         const HTryBoundary& stored_try_entry = block->GetTryCatchInformation()->GetTryEntry();
260         if (incoming_try_entry == nullptr) {
261           AddError(StringPrintf("Block %d has try entry %s:%d but no try entry follows "
262                                 "from predecessor %d.",
263                                 block->GetBlockId(),
264                                 stored_try_entry.DebugName(),
265                                 stored_try_entry.GetId(),
266                                 predecessor->GetBlockId()));
267         } else if (!incoming_try_entry->HasSameExceptionHandlersAs(stored_try_entry)) {
268           AddError(StringPrintf("Block %d has try entry %s:%d which is not consistent "
269                                 "with %s:%d that follows from predecessor %d.",
270                                 block->GetBlockId(),
271                                 stored_try_entry.DebugName(),
272                                 stored_try_entry.GetId(),
273                                 incoming_try_entry->DebugName(),
274                                 incoming_try_entry->GetId(),
275                                 predecessor->GetBlockId()));
276         }
277       } else if (incoming_try_entry != nullptr) {
278         AddError(StringPrintf("Block %d is not a try block but try entry %s:%d follows "
279                               "from predecessor %d.",
280                               block->GetBlockId(),
281                               incoming_try_entry->DebugName(),
282                               incoming_try_entry->GetId(),
283                               predecessor->GetBlockId()));
284       }
285     }
286   }
287 
288   if (block->IsLoopHeader()) {
289     HandleLoop(block);
290   }
291 }
292 
VisitBoundsCheck(HBoundsCheck * check)293 void GraphChecker::VisitBoundsCheck(HBoundsCheck* check) {
294   if (!GetGraph()->HasBoundsChecks()) {
295     AddError(StringPrintf("Instruction %s:%d is a HBoundsCheck, "
296                           "but HasBoundsChecks() returns false",
297                           check->DebugName(),
298                           check->GetId()));
299   }
300 
301   // Perform the instruction base checks too.
302   VisitInstruction(check);
303 }
304 
VisitDeoptimize(HDeoptimize * deopt)305 void GraphChecker::VisitDeoptimize(HDeoptimize* deopt) {
306   if (GetGraph()->IsCompilingOsr()) {
307     AddError(StringPrintf("A graph compiled OSR cannot have a HDeoptimize instruction"));
308   }
309 
310   // Perform the instruction base checks too.
311   VisitInstruction(deopt);
312 }
313 
VisitTryBoundary(HTryBoundary * try_boundary)314 void GraphChecker::VisitTryBoundary(HTryBoundary* try_boundary) {
315   ArrayRef<HBasicBlock* const> handlers = try_boundary->GetExceptionHandlers();
316 
317   // Ensure that all exception handlers are catch blocks.
318   // Note that a normal-flow successor may be a catch block before CFG
319   // simplification. We only test normal-flow successors in GraphChecker.
320   for (HBasicBlock* handler : handlers) {
321     if (!handler->IsCatchBlock()) {
322       AddError(StringPrintf("Block %d with %s:%d has exceptional successor %d which "
323                             "is not a catch block.",
324                             current_block_->GetBlockId(),
325                             try_boundary->DebugName(),
326                             try_boundary->GetId(),
327                             handler->GetBlockId()));
328     }
329   }
330 
331   // Ensure that handlers are not listed multiple times.
332   for (size_t i = 0, e = handlers.size(); i < e; ++i) {
333     if (ContainsElement(handlers, handlers[i], i + 1)) {
334         AddError(StringPrintf("Exception handler block %d of %s:%d is listed multiple times.",
335                             handlers[i]->GetBlockId(),
336                             try_boundary->DebugName(),
337                             try_boundary->GetId()));
338     }
339   }
340 
341   VisitInstruction(try_boundary);
342 }
343 
VisitLoadException(HLoadException * load)344 void GraphChecker::VisitLoadException(HLoadException* load) {
345   // Ensure that LoadException is the first instruction in a catch block.
346   if (!load->GetBlock()->IsCatchBlock()) {
347     AddError(StringPrintf("%s:%d is in a non-catch block %d.",
348                           load->DebugName(),
349                           load->GetId(),
350                           load->GetBlock()->GetBlockId()));
351   } else if (load->GetBlock()->GetFirstInstruction() != load) {
352     AddError(StringPrintf("%s:%d is not the first instruction in catch block %d.",
353                           load->DebugName(),
354                           load->GetId(),
355                           load->GetBlock()->GetBlockId()));
356   }
357 }
358 
VisitInstruction(HInstruction * instruction)359 void GraphChecker::VisitInstruction(HInstruction* instruction) {
360   if (seen_ids_.IsBitSet(instruction->GetId())) {
361     AddError(StringPrintf("Instruction id %d is duplicate in graph.",
362                           instruction->GetId()));
363   } else {
364     seen_ids_.SetBit(instruction->GetId());
365   }
366 
367   // Ensure `instruction` is associated with `current_block_`.
368   if (instruction->GetBlock() == nullptr) {
369     AddError(StringPrintf("%s %d in block %d not associated with any block.",
370                           instruction->IsPhi() ? "Phi" : "Instruction",
371                           instruction->GetId(),
372                           current_block_->GetBlockId()));
373   } else if (instruction->GetBlock() != current_block_) {
374     AddError(StringPrintf("%s %d in block %d associated with block %d.",
375                           instruction->IsPhi() ? "Phi" : "Instruction",
376                           instruction->GetId(),
377                           current_block_->GetBlockId(),
378                           instruction->GetBlock()->GetBlockId()));
379   }
380 
381   // Ensure the inputs of `instruction` are defined in a block of the graph.
382   for (HInstruction* input : instruction->GetInputs()) {
383     if (input->GetBlock() == nullptr) {
384       AddError(StringPrintf("Input %d of instruction %d is not in any "
385                             "basic block of the control-flow graph.",
386                             input->GetId(),
387                             instruction->GetId()));
388     } else {
389       const HInstructionList& list = input->IsPhi()
390           ? input->GetBlock()->GetPhis()
391           : input->GetBlock()->GetInstructions();
392       if (!list.Contains(input)) {
393         AddError(StringPrintf("Input %d of instruction %d is not defined "
394                               "in a basic block of the control-flow graph.",
395                               input->GetId(),
396                               instruction->GetId()));
397       }
398     }
399   }
400 
401   // Ensure the uses of `instruction` are defined in a block of the graph,
402   // and the entry in the use list is consistent.
403   for (const HUseListNode<HInstruction*>& use : instruction->GetUses()) {
404     HInstruction* user = use.GetUser();
405     const HInstructionList& list = user->IsPhi()
406         ? user->GetBlock()->GetPhis()
407         : user->GetBlock()->GetInstructions();
408     if (!list.Contains(user)) {
409       AddError(StringPrintf("User %s:%d of instruction %d is not defined "
410                             "in a basic block of the control-flow graph.",
411                             user->DebugName(),
412                             user->GetId(),
413                             instruction->GetId()));
414     }
415     size_t use_index = use.GetIndex();
416     HConstInputsRef user_inputs = user->GetInputs();
417     if ((use_index >= user_inputs.size()) || (user_inputs[use_index] != instruction)) {
418       AddError(StringPrintf("User %s:%d of instruction %s:%d has a wrong "
419                             "UseListNode index.",
420                             user->DebugName(),
421                             user->GetId(),
422                             instruction->DebugName(),
423                             instruction->GetId()));
424     }
425   }
426 
427   // Ensure the environment uses entries are consistent.
428   for (const HUseListNode<HEnvironment*>& use : instruction->GetEnvUses()) {
429     HEnvironment* user = use.GetUser();
430     size_t use_index = use.GetIndex();
431     if ((use_index >= user->Size()) || (user->GetInstructionAt(use_index) != instruction)) {
432       AddError(StringPrintf("Environment user of %s:%d has a wrong "
433                             "UseListNode index.",
434                             instruction->DebugName(),
435                             instruction->GetId()));
436     }
437   }
438 
439   // Ensure 'instruction' has pointers to its inputs' use entries.
440   auto&& input_records = instruction->GetInputRecords();
441   for (size_t i = 0; i < input_records.size(); ++i) {
442     const HUserRecord<HInstruction*>& input_record = input_records[i];
443     HInstruction* input = input_record.GetInstruction();
444     if ((input_record.GetBeforeUseNode() == input->GetUses().end()) ||
445         (input_record.GetUseNode() == input->GetUses().end()) ||
446         !input->GetUses().ContainsNode(*input_record.GetUseNode()) ||
447         (input_record.GetUseNode()->GetIndex() != i)) {
448       AddError(StringPrintf("Instruction %s:%d has an invalid iterator before use entry "
449                             "at input %u (%s:%d).",
450                             instruction->DebugName(),
451                             instruction->GetId(),
452                             static_cast<unsigned>(i),
453                             input->DebugName(),
454                             input->GetId()));
455     }
456   }
457 
458   // Ensure an instruction dominates all its uses.
459   for (const HUseListNode<HInstruction*>& use : instruction->GetUses()) {
460     HInstruction* user = use.GetUser();
461     if (!user->IsPhi() && !instruction->StrictlyDominates(user)) {
462       AddError(StringPrintf("Instruction %s:%d in block %d does not dominate "
463                             "use %s:%d in block %d.",
464                             instruction->DebugName(),
465                             instruction->GetId(),
466                             current_block_->GetBlockId(),
467                             user->DebugName(),
468                             user->GetId(),
469                             user->GetBlock()->GetBlockId()));
470     }
471   }
472 
473   if (instruction->NeedsEnvironment() && !instruction->HasEnvironment()) {
474     AddError(StringPrintf("Instruction %s:%d in block %d requires an environment "
475                           "but does not have one.",
476                           instruction->DebugName(),
477                           instruction->GetId(),
478                           current_block_->GetBlockId()));
479   }
480 
481   // Ensure an instruction having an environment is dominated by the
482   // instructions contained in the environment.
483   for (HEnvironment* environment = instruction->GetEnvironment();
484        environment != nullptr;
485        environment = environment->GetParent()) {
486     for (size_t i = 0, e = environment->Size(); i < e; ++i) {
487       HInstruction* env_instruction = environment->GetInstructionAt(i);
488       if (env_instruction != nullptr
489           && !env_instruction->StrictlyDominates(instruction)) {
490         AddError(StringPrintf("Instruction %d in environment of instruction %d "
491                               "from block %d does not dominate instruction %d.",
492                               env_instruction->GetId(),
493                               instruction->GetId(),
494                               current_block_->GetBlockId(),
495                               instruction->GetId()));
496       }
497     }
498   }
499 
500   // Ensure that reference type instructions have reference type info.
501   if (check_reference_type_info_ && instruction->GetType() == DataType::Type::kReference) {
502     if (!instruction->GetReferenceTypeInfo().IsValid()) {
503       AddError(StringPrintf("Reference type instruction %s:%d does not have "
504                             "valid reference type information.",
505                             instruction->DebugName(),
506                             instruction->GetId()));
507     }
508   }
509 
510   if (instruction->CanThrowIntoCatchBlock()) {
511     // Find the top-level environment. This corresponds to the environment of
512     // the catch block since we do not inline methods with try/catch.
513     HEnvironment* environment = instruction->GetEnvironment();
514     while (environment->GetParent() != nullptr) {
515       environment = environment->GetParent();
516     }
517 
518     // Find all catch blocks and test that `instruction` has an environment
519     // value for each one.
520     const HTryBoundary& entry = instruction->GetBlock()->GetTryCatchInformation()->GetTryEntry();
521     for (HBasicBlock* catch_block : entry.GetExceptionHandlers()) {
522       for (HInstructionIterator phi_it(catch_block->GetPhis()); !phi_it.Done(); phi_it.Advance()) {
523         HPhi* catch_phi = phi_it.Current()->AsPhi();
524         if (environment->GetInstructionAt(catch_phi->GetRegNumber()) == nullptr) {
525           AddError(StringPrintf("Instruction %s:%d throws into catch block %d "
526                                 "with catch phi %d for vreg %d but its "
527                                 "corresponding environment slot is empty.",
528                                 instruction->DebugName(),
529                                 instruction->GetId(),
530                                 catch_block->GetBlockId(),
531                                 catch_phi->GetId(),
532                                 catch_phi->GetRegNumber()));
533         }
534       }
535     }
536   }
537 }
538 
VisitInvokeStaticOrDirect(HInvokeStaticOrDirect * invoke)539 void GraphChecker::VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) {
540   VisitInstruction(invoke);
541 
542   if (invoke->IsStaticWithExplicitClinitCheck()) {
543     const HInstruction* last_input = invoke->GetInputs().back();
544     if (last_input == nullptr) {
545       AddError(StringPrintf("Static invoke %s:%d marked as having an explicit clinit check "
546                             "has a null pointer as last input.",
547                             invoke->DebugName(),
548                             invoke->GetId()));
549     } else if (!last_input->IsClinitCheck() && !last_input->IsLoadClass()) {
550       AddError(StringPrintf("Static invoke %s:%d marked as having an explicit clinit check "
551                             "has a last instruction (%s:%d) which is neither a clinit check "
552                             "nor a load class instruction.",
553                             invoke->DebugName(),
554                             invoke->GetId(),
555                             last_input->DebugName(),
556                             last_input->GetId()));
557     }
558   }
559 }
560 
VisitReturn(HReturn * ret)561 void GraphChecker::VisitReturn(HReturn* ret) {
562   VisitInstruction(ret);
563   HBasicBlock* successor = ret->GetBlock()->GetSingleSuccessor();
564   if (!successor->IsExitBlock() && !IsExitTryBoundaryIntoExitBlock(successor)) {
565     AddError(StringPrintf("%s:%d does not jump to the exit block.",
566                           ret->DebugName(),
567                           ret->GetId()));
568   }
569 }
570 
VisitReturnVoid(HReturnVoid * ret)571 void GraphChecker::VisitReturnVoid(HReturnVoid* ret) {
572   VisitInstruction(ret);
573   HBasicBlock* successor = ret->GetBlock()->GetSingleSuccessor();
574   if (!successor->IsExitBlock() && !IsExitTryBoundaryIntoExitBlock(successor)) {
575     AddError(StringPrintf("%s:%d does not jump to the exit block.",
576                           ret->DebugName(),
577                           ret->GetId()));
578   }
579 }
580 
CheckTypeCheckBitstringInput(HTypeCheckInstruction * check,size_t input_pos,bool check_value,uint32_t expected_value,const char * name)581 void GraphChecker::CheckTypeCheckBitstringInput(HTypeCheckInstruction* check,
582                                                 size_t input_pos,
583                                                 bool check_value,
584                                                 uint32_t expected_value,
585                                                 const char* name) {
586   if (!check->InputAt(input_pos)->IsIntConstant()) {
587     AddError(StringPrintf("%s:%d (bitstring) expects a HIntConstant input %zu (%s), not %s:%d.",
588                           check->DebugName(),
589                           check->GetId(),
590                           input_pos,
591                           name,
592                           check->InputAt(2)->DebugName(),
593                           check->InputAt(2)->GetId()));
594   } else if (check_value) {
595     uint32_t actual_value =
596         static_cast<uint32_t>(check->InputAt(input_pos)->AsIntConstant()->GetValue());
597     if (actual_value != expected_value) {
598       AddError(StringPrintf("%s:%d (bitstring) has %s 0x%x, not 0x%x as expected.",
599                             check->DebugName(),
600                             check->GetId(),
601                             name,
602                             actual_value,
603                             expected_value));
604     }
605   }
606 }
607 
HandleTypeCheckInstruction(HTypeCheckInstruction * check)608 void GraphChecker::HandleTypeCheckInstruction(HTypeCheckInstruction* check) {
609   VisitInstruction(check);
610   HInstruction* input = check->InputAt(1);
611   if (check->GetTypeCheckKind() == TypeCheckKind::kBitstringCheck) {
612     if (!input->IsNullConstant()) {
613       AddError(StringPrintf("%s:%d (bitstring) expects a HNullConstant as second input, not %s:%d.",
614                             check->DebugName(),
615                             check->GetId(),
616                             input->DebugName(),
617                             input->GetId()));
618     }
619     bool check_values = false;
620     BitString::StorageType expected_path_to_root = 0u;
621     BitString::StorageType expected_mask = 0u;
622     {
623       ScopedObjectAccess soa(Thread::Current());
624       ObjPtr<mirror::Class> klass = check->GetClass().Get();
625       MutexLock subtype_check_lock(Thread::Current(), *Locks::subtype_check_lock_);
626       SubtypeCheckInfo::State state = SubtypeCheck<ObjPtr<mirror::Class>>::GetState(klass);
627       if (state == SubtypeCheckInfo::kAssigned) {
628         expected_path_to_root =
629             SubtypeCheck<ObjPtr<mirror::Class>>::GetEncodedPathToRootForTarget(klass);
630         expected_mask = SubtypeCheck<ObjPtr<mirror::Class>>::GetEncodedPathToRootMask(klass);
631         check_values = true;
632       } else {
633         AddError(StringPrintf("%s:%d (bitstring) references a class with unassigned bitstring.",
634                               check->DebugName(),
635                               check->GetId()));
636       }
637     }
638     CheckTypeCheckBitstringInput(
639         check, /* input_pos= */ 2, check_values, expected_path_to_root, "path_to_root");
640     CheckTypeCheckBitstringInput(check, /* input_pos= */ 3, check_values, expected_mask, "mask");
641   } else {
642     if (!input->IsLoadClass()) {
643       AddError(StringPrintf("%s:%d (classic) expects a HLoadClass as second input, not %s:%d.",
644                             check->DebugName(),
645                             check->GetId(),
646                             input->DebugName(),
647                             input->GetId()));
648     }
649   }
650 }
651 
VisitCheckCast(HCheckCast * check)652 void GraphChecker::VisitCheckCast(HCheckCast* check) {
653   HandleTypeCheckInstruction(check);
654 }
655 
VisitInstanceOf(HInstanceOf * instruction)656 void GraphChecker::VisitInstanceOf(HInstanceOf* instruction) {
657   HandleTypeCheckInstruction(instruction);
658 }
659 
HandleLoop(HBasicBlock * loop_header)660 void GraphChecker::HandleLoop(HBasicBlock* loop_header) {
661   int id = loop_header->GetBlockId();
662   HLoopInformation* loop_information = loop_header->GetLoopInformation();
663 
664   if (loop_information->GetPreHeader()->GetSuccessors().size() != 1) {
665     AddError(StringPrintf(
666         "Loop pre-header %d of loop defined by header %d has %zu successors.",
667         loop_information->GetPreHeader()->GetBlockId(),
668         id,
669         loop_information->GetPreHeader()->GetSuccessors().size()));
670   }
671 
672   if (loop_information->GetSuspendCheck() == nullptr) {
673     AddError(StringPrintf(
674         "Loop with header %d does not have a suspend check.",
675         loop_header->GetBlockId()));
676   }
677 
678   if (loop_information->GetSuspendCheck() != loop_header->GetFirstInstructionDisregardMoves()) {
679     AddError(StringPrintf(
680         "Loop header %d does not have the loop suspend check as the first instruction.",
681         loop_header->GetBlockId()));
682   }
683 
684   // Ensure the loop header has only one incoming branch and the remaining
685   // predecessors are back edges.
686   size_t num_preds = loop_header->GetPredecessors().size();
687   if (num_preds < 2) {
688     AddError(StringPrintf(
689         "Loop header %d has less than two predecessors: %zu.",
690         id,
691         num_preds));
692   } else {
693     HBasicBlock* first_predecessor = loop_header->GetPredecessors()[0];
694     if (loop_information->IsBackEdge(*first_predecessor)) {
695       AddError(StringPrintf(
696           "First predecessor of loop header %d is a back edge.",
697           id));
698     }
699     for (size_t i = 1, e = loop_header->GetPredecessors().size(); i < e; ++i) {
700       HBasicBlock* predecessor = loop_header->GetPredecessors()[i];
701       if (!loop_information->IsBackEdge(*predecessor)) {
702         AddError(StringPrintf(
703             "Loop header %d has multiple incoming (non back edge) blocks: %d.",
704             id,
705             predecessor->GetBlockId()));
706       }
707     }
708   }
709 
710   const ArenaBitVector& loop_blocks = loop_information->GetBlocks();
711 
712   // Ensure back edges belong to the loop.
713   if (loop_information->NumberOfBackEdges() == 0) {
714     AddError(StringPrintf(
715         "Loop defined by header %d has no back edge.",
716         id));
717   } else {
718     for (HBasicBlock* back_edge : loop_information->GetBackEdges()) {
719       int back_edge_id = back_edge->GetBlockId();
720       if (!loop_blocks.IsBitSet(back_edge_id)) {
721         AddError(StringPrintf(
722             "Loop defined by header %d has an invalid back edge %d.",
723             id,
724             back_edge_id));
725       } else if (back_edge->GetLoopInformation() != loop_information) {
726         AddError(StringPrintf(
727             "Back edge %d of loop defined by header %d belongs to nested loop "
728             "with header %d.",
729             back_edge_id,
730             id,
731             back_edge->GetLoopInformation()->GetHeader()->GetBlockId()));
732       }
733     }
734   }
735 
736   // If this is a nested loop, ensure the outer loops contain a superset of the blocks.
737   for (HLoopInformationOutwardIterator it(*loop_header); !it.Done(); it.Advance()) {
738     HLoopInformation* outer_info = it.Current();
739     if (!loop_blocks.IsSubsetOf(&outer_info->GetBlocks())) {
740       AddError(StringPrintf("Blocks of loop defined by header %d are not a subset of blocks of "
741                             "an outer loop defined by header %d.",
742                             id,
743                             outer_info->GetHeader()->GetBlockId()));
744     }
745   }
746 
747   // Ensure the pre-header block is first in the list of predecessors of a loop
748   // header and that the header block is its only successor.
749   if (!loop_header->IsLoopPreHeaderFirstPredecessor()) {
750     AddError(StringPrintf(
751         "Loop pre-header is not the first predecessor of the loop header %d.",
752         id));
753   }
754 
755   // Ensure all blocks in the loop are live and dominated by the loop header in
756   // the case of natural loops.
757   for (uint32_t i : loop_blocks.Indexes()) {
758     HBasicBlock* loop_block = GetGraph()->GetBlocks()[i];
759     if (loop_block == nullptr) {
760       AddError(StringPrintf("Loop defined by header %d contains a previously removed block %d.",
761                             id,
762                             i));
763     } else if (!loop_information->IsIrreducible() && !loop_header->Dominates(loop_block)) {
764       AddError(StringPrintf("Loop block %d not dominated by loop header %d.",
765                             i,
766                             id));
767     }
768   }
769 }
770 
IsSameSizeConstant(const HInstruction * insn1,const HInstruction * insn2)771 static bool IsSameSizeConstant(const HInstruction* insn1, const HInstruction* insn2) {
772   return insn1->IsConstant()
773       && insn2->IsConstant()
774       && DataType::Is64BitType(insn1->GetType()) == DataType::Is64BitType(insn2->GetType());
775 }
776 
IsConstantEquivalent(const HInstruction * insn1,const HInstruction * insn2,BitVector * visited)777 static bool IsConstantEquivalent(const HInstruction* insn1,
778                                  const HInstruction* insn2,
779                                  BitVector* visited) {
780   if (insn1->IsPhi() &&
781       insn1->AsPhi()->IsVRegEquivalentOf(insn2)) {
782     HConstInputsRef insn1_inputs = insn1->GetInputs();
783     HConstInputsRef insn2_inputs = insn2->GetInputs();
784     if (insn1_inputs.size() != insn2_inputs.size()) {
785       return false;
786     }
787 
788     // Testing only one of the two inputs for recursion is sufficient.
789     if (visited->IsBitSet(insn1->GetId())) {
790       return true;
791     }
792     visited->SetBit(insn1->GetId());
793 
794     for (size_t i = 0; i < insn1_inputs.size(); ++i) {
795       if (!IsConstantEquivalent(insn1_inputs[i], insn2_inputs[i], visited)) {
796         return false;
797       }
798     }
799     return true;
800   } else if (IsSameSizeConstant(insn1, insn2)) {
801     return insn1->AsConstant()->GetValueAsUint64() == insn2->AsConstant()->GetValueAsUint64();
802   } else {
803     return false;
804   }
805 }
806 
VisitPhi(HPhi * phi)807 void GraphChecker::VisitPhi(HPhi* phi) {
808   VisitInstruction(phi);
809 
810   // Ensure the first input of a phi is not itself.
811   ArrayRef<HUserRecord<HInstruction*>> input_records = phi->GetInputRecords();
812   if (input_records[0].GetInstruction() == phi) {
813     AddError(StringPrintf("Loop phi %d in block %d is its own first input.",
814                           phi->GetId(),
815                           phi->GetBlock()->GetBlockId()));
816   }
817 
818   // Ensure that the inputs have the same primitive kind as the phi.
819   for (size_t i = 0; i < input_records.size(); ++i) {
820     HInstruction* input = input_records[i].GetInstruction();
821     if (DataType::Kind(input->GetType()) != DataType::Kind(phi->GetType())) {
822         AddError(StringPrintf(
823             "Input %d at index %zu of phi %d from block %d does not have the "
824             "same kind as the phi: %s versus %s",
825             input->GetId(), i, phi->GetId(), phi->GetBlock()->GetBlockId(),
826             DataType::PrettyDescriptor(input->GetType()),
827             DataType::PrettyDescriptor(phi->GetType())));
828     }
829   }
830   if (phi->GetType() != HPhi::ToPhiType(phi->GetType())) {
831     AddError(StringPrintf("Phi %d in block %d does not have an expected phi type: %s",
832                           phi->GetId(),
833                           phi->GetBlock()->GetBlockId(),
834                           DataType::PrettyDescriptor(phi->GetType())));
835   }
836 
837   if (phi->IsCatchPhi()) {
838     // The number of inputs of a catch phi should be the total number of throwing
839     // instructions caught by this catch block. We do not enforce this, however,
840     // because we do not remove the corresponding inputs when we prove that an
841     // instruction cannot throw. Instead, we at least test that all phis have the
842     // same, non-zero number of inputs (b/24054676).
843     if (input_records.empty()) {
844       AddError(StringPrintf("Phi %d in catch block %d has zero inputs.",
845                             phi->GetId(),
846                             phi->GetBlock()->GetBlockId()));
847     } else {
848       HInstruction* next_phi = phi->GetNext();
849       if (next_phi != nullptr) {
850         size_t input_count_next = next_phi->InputCount();
851         if (input_records.size() != input_count_next) {
852           AddError(StringPrintf("Phi %d in catch block %d has %zu inputs, "
853                                 "but phi %d has %zu inputs.",
854                                 phi->GetId(),
855                                 phi->GetBlock()->GetBlockId(),
856                                 input_records.size(),
857                                 next_phi->GetId(),
858                                 input_count_next));
859         }
860       }
861     }
862   } else {
863     // Ensure the number of inputs of a non-catch phi is the same as the number
864     // of its predecessors.
865     const ArenaVector<HBasicBlock*>& predecessors = phi->GetBlock()->GetPredecessors();
866     if (input_records.size() != predecessors.size()) {
867       AddError(StringPrintf(
868           "Phi %d in block %d has %zu inputs, "
869           "but block %d has %zu predecessors.",
870           phi->GetId(), phi->GetBlock()->GetBlockId(), input_records.size(),
871           phi->GetBlock()->GetBlockId(), predecessors.size()));
872     } else {
873       // Ensure phi input at index I either comes from the Ith
874       // predecessor or from a block that dominates this predecessor.
875       for (size_t i = 0; i < input_records.size(); ++i) {
876         HInstruction* input = input_records[i].GetInstruction();
877         HBasicBlock* predecessor = predecessors[i];
878         if (!(input->GetBlock() == predecessor
879               || input->GetBlock()->Dominates(predecessor))) {
880           AddError(StringPrintf(
881               "Input %d at index %zu of phi %d from block %d is not defined in "
882               "predecessor number %zu nor in a block dominating it.",
883               input->GetId(), i, phi->GetId(), phi->GetBlock()->GetBlockId(),
884               i));
885         }
886       }
887     }
888   }
889 
890   // Ensure that catch phis are sorted by their vreg number, as required by
891   // the register allocator and code generator. This does not apply to normal
892   // phis which can be constructed artifically.
893   if (phi->IsCatchPhi()) {
894     HInstruction* next_phi = phi->GetNext();
895     if (next_phi != nullptr && phi->GetRegNumber() > next_phi->AsPhi()->GetRegNumber()) {
896       AddError(StringPrintf("Catch phis %d and %d in block %d are not sorted by their "
897                             "vreg numbers.",
898                             phi->GetId(),
899                             next_phi->GetId(),
900                             phi->GetBlock()->GetBlockId()));
901     }
902   }
903 
904   // Test phi equivalents. There should not be two of the same type and they should only be
905   // created for constants which were untyped in DEX. Note that this test can be skipped for
906   // a synthetic phi (indicated by lack of a virtual register).
907   if (phi->GetRegNumber() != kNoRegNumber) {
908     for (HInstructionIterator phi_it(phi->GetBlock()->GetPhis());
909          !phi_it.Done();
910          phi_it.Advance()) {
911       HPhi* other_phi = phi_it.Current()->AsPhi();
912       if (phi != other_phi && phi->GetRegNumber() == other_phi->GetRegNumber()) {
913         if (phi->GetType() == other_phi->GetType()) {
914           std::stringstream type_str;
915           type_str << phi->GetType();
916           AddError(StringPrintf("Equivalent phi (%d) found for VReg %d with type: %s.",
917                                 phi->GetId(),
918                                 phi->GetRegNumber(),
919                                 type_str.str().c_str()));
920         } else if (phi->GetType() == DataType::Type::kReference) {
921           std::stringstream type_str;
922           type_str << other_phi->GetType();
923           AddError(StringPrintf(
924               "Equivalent non-reference phi (%d) found for VReg %d with type: %s.",
925               phi->GetId(),
926               phi->GetRegNumber(),
927               type_str.str().c_str()));
928         } else {
929           // Use local allocator for allocating memory.
930           ScopedArenaAllocator allocator(GetGraph()->GetArenaStack());
931           // If we get here, make sure we allocate all the necessary storage at once
932           // because the BitVector reallocation strategy has very bad worst-case behavior.
933           ArenaBitVector visited(&allocator,
934                                  GetGraph()->GetCurrentInstructionId(),
935                                  /* expandable= */ false,
936                                  kArenaAllocGraphChecker);
937           visited.ClearAllBits();
938           if (!IsConstantEquivalent(phi, other_phi, &visited)) {
939             AddError(StringPrintf("Two phis (%d and %d) found for VReg %d but they "
940                                   "are not equivalents of constants.",
941                                   phi->GetId(),
942                                   other_phi->GetId(),
943                                   phi->GetRegNumber()));
944           }
945         }
946       }
947     }
948   }
949 }
950 
HandleBooleanInput(HInstruction * instruction,size_t input_index)951 void GraphChecker::HandleBooleanInput(HInstruction* instruction, size_t input_index) {
952   HInstruction* input = instruction->InputAt(input_index);
953   if (input->IsIntConstant()) {
954     int32_t value = input->AsIntConstant()->GetValue();
955     if (value != 0 && value != 1) {
956       AddError(StringPrintf(
957           "%s instruction %d has a non-Boolean constant input %d whose value is: %d.",
958           instruction->DebugName(),
959           instruction->GetId(),
960           static_cast<int>(input_index),
961           value));
962     }
963   } else if (DataType::Kind(input->GetType()) != DataType::Type::kInt32) {
964     // TODO: We need a data-flow analysis to determine if an input like Phi,
965     //       Select or a binary operation is actually Boolean. Allow for now.
966     AddError(StringPrintf(
967         "%s instruction %d has a non-integer input %d whose type is: %s.",
968         instruction->DebugName(),
969         instruction->GetId(),
970         static_cast<int>(input_index),
971         DataType::PrettyDescriptor(input->GetType())));
972   }
973 }
974 
VisitPackedSwitch(HPackedSwitch * instruction)975 void GraphChecker::VisitPackedSwitch(HPackedSwitch* instruction) {
976   VisitInstruction(instruction);
977   // Check that the number of block successors matches the switch count plus
978   // one for the default block.
979   HBasicBlock* block = instruction->GetBlock();
980   if (instruction->GetNumEntries() + 1u != block->GetSuccessors().size()) {
981     AddError(StringPrintf(
982         "%s instruction %d in block %d expects %u successors to the block, but found: %zu.",
983         instruction->DebugName(),
984         instruction->GetId(),
985         block->GetBlockId(),
986         instruction->GetNumEntries() + 1u,
987         block->GetSuccessors().size()));
988   }
989 }
990 
VisitIf(HIf * instruction)991 void GraphChecker::VisitIf(HIf* instruction) {
992   VisitInstruction(instruction);
993   HandleBooleanInput(instruction, 0);
994 }
995 
VisitSelect(HSelect * instruction)996 void GraphChecker::VisitSelect(HSelect* instruction) {
997   VisitInstruction(instruction);
998   HandleBooleanInput(instruction, 2);
999 }
1000 
VisitBooleanNot(HBooleanNot * instruction)1001 void GraphChecker::VisitBooleanNot(HBooleanNot* instruction) {
1002   VisitInstruction(instruction);
1003   HandleBooleanInput(instruction, 0);
1004 }
1005 
VisitCondition(HCondition * op)1006 void GraphChecker::VisitCondition(HCondition* op) {
1007   VisitInstruction(op);
1008   if (op->GetType() != DataType::Type::kBool) {
1009     AddError(StringPrintf(
1010         "Condition %s %d has a non-Boolean result type: %s.",
1011         op->DebugName(), op->GetId(),
1012         DataType::PrettyDescriptor(op->GetType())));
1013   }
1014   HInstruction* lhs = op->InputAt(0);
1015   HInstruction* rhs = op->InputAt(1);
1016   if (DataType::Kind(lhs->GetType()) != DataType::Kind(rhs->GetType())) {
1017     AddError(StringPrintf(
1018         "Condition %s %d has inputs of different kinds: %s, and %s.",
1019         op->DebugName(), op->GetId(),
1020         DataType::PrettyDescriptor(lhs->GetType()),
1021         DataType::PrettyDescriptor(rhs->GetType())));
1022   }
1023   if (!op->IsEqual() && !op->IsNotEqual()) {
1024     if ((lhs->GetType() == DataType::Type::kReference)) {
1025       AddError(StringPrintf(
1026           "Condition %s %d uses an object as left-hand side input.",
1027           op->DebugName(), op->GetId()));
1028     } else if (rhs->GetType() == DataType::Type::kReference) {
1029       AddError(StringPrintf(
1030           "Condition %s %d uses an object as right-hand side input.",
1031           op->DebugName(), op->GetId()));
1032     }
1033   }
1034 }
1035 
VisitNeg(HNeg * instruction)1036 void GraphChecker::VisitNeg(HNeg* instruction) {
1037   VisitInstruction(instruction);
1038   DataType::Type input_type = instruction->InputAt(0)->GetType();
1039   DataType::Type result_type = instruction->GetType();
1040   if (result_type != DataType::Kind(input_type)) {
1041     AddError(StringPrintf("Binary operation %s %d has a result type different "
1042                           "from its input kind: %s vs %s.",
1043                           instruction->DebugName(), instruction->GetId(),
1044                           DataType::PrettyDescriptor(result_type),
1045                           DataType::PrettyDescriptor(input_type)));
1046   }
1047 }
1048 
VisitBinaryOperation(HBinaryOperation * op)1049 void GraphChecker::VisitBinaryOperation(HBinaryOperation* op) {
1050   VisitInstruction(op);
1051   DataType::Type lhs_type = op->InputAt(0)->GetType();
1052   DataType::Type rhs_type = op->InputAt(1)->GetType();
1053   DataType::Type result_type = op->GetType();
1054 
1055   // Type consistency between inputs.
1056   if (op->IsUShr() || op->IsShr() || op->IsShl() || op->IsRor()) {
1057     if (DataType::Kind(rhs_type) != DataType::Type::kInt32) {
1058       AddError(StringPrintf("Shift/rotate operation %s %d has a non-int kind second input: "
1059                             "%s of type %s.",
1060                             op->DebugName(), op->GetId(),
1061                             op->InputAt(1)->DebugName(),
1062                             DataType::PrettyDescriptor(rhs_type)));
1063     }
1064   } else {
1065     if (DataType::Kind(lhs_type) != DataType::Kind(rhs_type)) {
1066       AddError(StringPrintf("Binary operation %s %d has inputs of different kinds: %s, and %s.",
1067                             op->DebugName(), op->GetId(),
1068                             DataType::PrettyDescriptor(lhs_type),
1069                             DataType::PrettyDescriptor(rhs_type)));
1070     }
1071   }
1072 
1073   // Type consistency between result and input(s).
1074   if (op->IsCompare()) {
1075     if (result_type != DataType::Type::kInt32) {
1076       AddError(StringPrintf("Compare operation %d has a non-int result type: %s.",
1077                             op->GetId(),
1078                             DataType::PrettyDescriptor(result_type)));
1079     }
1080   } else if (op->IsUShr() || op->IsShr() || op->IsShl() || op->IsRor()) {
1081     // Only check the first input (value), as the second one (distance)
1082     // must invariably be of kind `int`.
1083     if (result_type != DataType::Kind(lhs_type)) {
1084       AddError(StringPrintf("Shift/rotate operation %s %d has a result type different "
1085                             "from its left-hand side (value) input kind: %s vs %s.",
1086                             op->DebugName(), op->GetId(),
1087                             DataType::PrettyDescriptor(result_type),
1088                             DataType::PrettyDescriptor(lhs_type)));
1089     }
1090   } else {
1091     if (DataType::Kind(result_type) != DataType::Kind(lhs_type)) {
1092       AddError(StringPrintf("Binary operation %s %d has a result kind different "
1093                             "from its left-hand side input kind: %s vs %s.",
1094                             op->DebugName(), op->GetId(),
1095                             DataType::PrettyDescriptor(result_type),
1096                             DataType::PrettyDescriptor(lhs_type)));
1097     }
1098     if (DataType::Kind(result_type) != DataType::Kind(rhs_type)) {
1099       AddError(StringPrintf("Binary operation %s %d has a result kind different "
1100                             "from its right-hand side input kind: %s vs %s.",
1101                             op->DebugName(), op->GetId(),
1102                             DataType::PrettyDescriptor(result_type),
1103                             DataType::PrettyDescriptor(rhs_type)));
1104     }
1105   }
1106 }
1107 
VisitConstant(HConstant * instruction)1108 void GraphChecker::VisitConstant(HConstant* instruction) {
1109   HBasicBlock* block = instruction->GetBlock();
1110   if (!block->IsEntryBlock()) {
1111     AddError(StringPrintf(
1112         "%s %d should be in the entry block but is in block %d.",
1113         instruction->DebugName(),
1114         instruction->GetId(),
1115         block->GetBlockId()));
1116   }
1117 }
1118 
VisitBoundType(HBoundType * instruction)1119 void GraphChecker::VisitBoundType(HBoundType* instruction) {
1120   VisitInstruction(instruction);
1121 
1122   if (!instruction->GetUpperBound().IsValid()) {
1123     AddError(StringPrintf(
1124         "%s %d does not have a valid upper bound RTI.",
1125         instruction->DebugName(),
1126         instruction->GetId()));
1127   }
1128 }
1129 
VisitTypeConversion(HTypeConversion * instruction)1130 void GraphChecker::VisitTypeConversion(HTypeConversion* instruction) {
1131   VisitInstruction(instruction);
1132   DataType::Type result_type = instruction->GetResultType();
1133   DataType::Type input_type = instruction->GetInputType();
1134   // Invariant: We should never generate a conversion to a Boolean value.
1135   if (result_type == DataType::Type::kBool) {
1136     AddError(StringPrintf(
1137         "%s %d converts to a %s (from a %s).",
1138         instruction->DebugName(),
1139         instruction->GetId(),
1140         DataType::PrettyDescriptor(result_type),
1141         DataType::PrettyDescriptor(input_type)));
1142   }
1143 }
1144 
VisitVecOperation(HVecOperation * instruction)1145 void GraphChecker::VisitVecOperation(HVecOperation* instruction) {
1146   VisitInstruction(instruction);
1147   if (codegen_ == nullptr) {
1148     return;
1149   }
1150 
1151   if (!codegen_->SupportsPredicatedSIMD() && instruction->IsPredicated()) {
1152     AddError(StringPrintf(
1153              "%s %d must not be predicated.",
1154              instruction->DebugName(),
1155              instruction->GetId()));
1156   }
1157 
1158   if (codegen_->SupportsPredicatedSIMD() &&
1159       (instruction->MustBePredicatedInPredicatedSIMDMode() != instruction->IsPredicated())) {
1160     AddError(StringPrintf(
1161              "%s %d predication mode is incorrect; see HVecOperation::MustBePredicated.",
1162              instruction->DebugName(),
1163              instruction->GetId()));
1164   }
1165 }
1166 
1167 }  // namespace art
1168