/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "graph_checker.h"
#include <algorithm>
#include <string>
#include <sstream>
#include "android-base/stringprintf.h"
#include "base/arena_containers.h"
#include "base/bit_vector-inl.h"
namespace art {
using android::base::StringPrintf;
static bool IsAllowedToJumpToExitBlock(HInstruction* instruction) {
return instruction->IsThrow() || instruction->IsReturn() || instruction->IsReturnVoid();
}
static bool IsExitTryBoundaryIntoExitBlock(HBasicBlock* block) {
if (!block->IsSingleTryBoundary()) {
return false;
}
HTryBoundary* boundary = block->GetLastInstruction()->AsTryBoundary();
return block->GetPredecessors().size() == 1u &&
boundary->GetNormalFlowSuccessor()->IsExitBlock() &&
!boundary->IsEntry();
}
void GraphChecker::VisitBasicBlock(HBasicBlock* block) {
current_block_ = block;
// Check consistency with respect to predecessors of `block`.
// Note: Counting duplicates with a sorted vector uses up to 6x less memory
// than ArenaSafeMap<HBasicBlock*, size_t> and also allows storage reuse.
ArenaVector<HBasicBlock*>& sorted_predecessors = blocks_storage_;
sorted_predecessors.assign(block->GetPredecessors().begin(), block->GetPredecessors().end());
std::sort(sorted_predecessors.begin(), sorted_predecessors.end());
for (auto it = sorted_predecessors.begin(), end = sorted_predecessors.end(); it != end; ) {
HBasicBlock* p = *it++;
size_t p_count_in_block_predecessors = 1u;
for (; it != end && *it == p; ++it) {
++p_count_in_block_predecessors;
}
size_t block_count_in_p_successors =
std::count(p->GetSuccessors().begin(), p->GetSuccessors().end(), block);
if (p_count_in_block_predecessors != block_count_in_p_successors) {
AddError(StringPrintf(
"Block %d lists %zu occurrences of block %d in its predecessors, whereas "
"block %d lists %zu occurrences of block %d in its successors.",
block->GetBlockId(), p_count_in_block_predecessors, p->GetBlockId(),
p->GetBlockId(), block_count_in_p_successors, block->GetBlockId()));
}
}
// Check consistency with respect to successors of `block`.
// Note: Counting duplicates with a sorted vector uses up to 6x less memory
// than ArenaSafeMap<HBasicBlock*, size_t> and also allows storage reuse.
ArenaVector<HBasicBlock*>& sorted_successors = blocks_storage_;
sorted_successors.assign(block->GetSuccessors().begin(), block->GetSuccessors().end());
std::sort(sorted_successors.begin(), sorted_successors.end());
for (auto it = sorted_successors.begin(), end = sorted_successors.end(); it != end; ) {
HBasicBlock* s = *it++;
size_t s_count_in_block_successors = 1u;
for (; it != end && *it == s; ++it) {
++s_count_in_block_successors;
}
size_t block_count_in_s_predecessors =
std::count(s->GetPredecessors().begin(), s->GetPredecessors().end(), block);
if (s_count_in_block_successors != block_count_in_s_predecessors) {
AddError(StringPrintf(
"Block %d lists %zu occurrences of block %d in its successors, whereas "
"block %d lists %zu occurrences of block %d in its predecessors.",
block->GetBlockId(), s_count_in_block_successors, s->GetBlockId(),
s->GetBlockId(), block_count_in_s_predecessors, block->GetBlockId()));
}
}
// Ensure `block` ends with a branch instruction.
// This invariant is not enforced on non-SSA graphs. Graph built from DEX with
// dead code that falls out of the method will not end with a control-flow
// instruction. Such code is removed during the SSA-building DCE phase.
if (GetGraph()->IsInSsaForm() && !block->EndsWithControlFlowInstruction()) {
AddError(StringPrintf("Block %d does not end with a branch instruction.",
block->GetBlockId()));
}
// Ensure that only Return(Void) and Throw jump to Exit. An exiting TryBoundary
// may be between the instructions if the Throw/Return(Void) is in a try block.
if (block->IsExitBlock()) {
for (HBasicBlock* predecessor : block->GetPredecessors()) {
HInstruction* last_instruction = IsExitTryBoundaryIntoExitBlock(predecessor) ?
predecessor->GetSinglePredecessor()->GetLastInstruction() :
predecessor->GetLastInstruction();
if (!IsAllowedToJumpToExitBlock(last_instruction)) {
AddError(StringPrintf("Unexpected instruction %s:%d jumps into the exit block.",
last_instruction->DebugName(),
last_instruction->GetId()));
}
}
}
// Visit this block's list of phis.
for (HInstructionIterator it(block->GetPhis()); !it.Done(); it.Advance()) {
HInstruction* current = it.Current();
// Ensure this block's list of phis contains only phis.
if (!current->IsPhi()) {
AddError(StringPrintf("Block %d has a non-phi in its phi list.",
current_block_->GetBlockId()));
}
if (current->GetNext() == nullptr && current != block->GetLastPhi()) {
AddError(StringPrintf("The recorded last phi of block %d does not match "
"the actual last phi %d.",
current_block_->GetBlockId(),
current->GetId()));
}
current->Accept(this);
}
// Visit this block's list of instructions.
for (HInstructionIterator it(block->GetInstructions()); !it.Done(); it.Advance()) {
HInstruction* current = it.Current();
// Ensure this block's list of instructions does not contains phis.
if (current->IsPhi()) {
AddError(StringPrintf("Block %d has a phi in its non-phi list.",
current_block_->GetBlockId()));
}
if (current->GetNext() == nullptr && current != block->GetLastInstruction()) {
AddError(StringPrintf("The recorded last instruction of block %d does not match "
"the actual last instruction %d.",
current_block_->GetBlockId(),
current->GetId()));
}
current->Accept(this);
}
// Ensure that catch blocks are not normal successors, and normal blocks are
// never exceptional successors.
for (HBasicBlock* successor : block->GetNormalSuccessors()) {
if (successor->IsCatchBlock()) {
AddError(StringPrintf("Catch block %d is a normal successor of block %d.",
successor->GetBlockId(),
block->GetBlockId()));
}
}
for (HBasicBlock* successor : block->GetExceptionalSuccessors()) {
if (!successor->IsCatchBlock()) {
AddError(StringPrintf("Normal block %d is an exceptional successor of block %d.",
successor->GetBlockId(),
block->GetBlockId()));
}
}
// Ensure dominated blocks have `block` as the dominator.
for (HBasicBlock* dominated : block->GetDominatedBlocks()) {
if (dominated->GetDominator() != block) {
AddError(StringPrintf("Block %d should be the dominator of %d.",
block->GetBlockId(),
dominated->GetBlockId()));
}
}
// Ensure there is no critical edge (i.e., an edge connecting a
// block with multiple successors to a block with multiple
// predecessors). Exceptional edges are synthesized and hence
// not accounted for.
if (block->GetSuccessors().size() > 1) {
if (IsExitTryBoundaryIntoExitBlock(block)) {
// Allowed critical edge (Throw/Return/ReturnVoid)->TryBoundary->Exit.
} else {
for (HBasicBlock* successor : block->GetNormalSuccessors()) {
if (successor->GetPredecessors().size() > 1) {
AddError(StringPrintf("Critical edge between blocks %d and %d.",
block->GetBlockId(),
successor->GetBlockId()));
}
}
}
}
// Ensure try membership information is consistent.
if (block->IsCatchBlock()) {
if (block->IsTryBlock()) {
const HTryBoundary& try_entry = block->GetTryCatchInformation()->GetTryEntry();
AddError(StringPrintf("Catch blocks should not be try blocks but catch block %d "
"has try entry %s:%d.",
block->GetBlockId(),
try_entry.DebugName(),
try_entry.GetId()));
}
if (block->IsLoopHeader()) {
AddError(StringPrintf("Catch blocks should not be loop headers but catch block %d is.",
block->GetBlockId()));
}
} else {
for (HBasicBlock* predecessor : block->GetPredecessors()) {
const HTryBoundary* incoming_try_entry = predecessor->ComputeTryEntryOfSuccessors();
if (block->IsTryBlock()) {
const HTryBoundary& stored_try_entry = block->GetTryCatchInformation()->GetTryEntry();
if (incoming_try_entry == nullptr) {
AddError(StringPrintf("Block %d has try entry %s:%d but no try entry follows "
"from predecessor %d.",
block->GetBlockId(),
stored_try_entry.DebugName(),
stored_try_entry.GetId(),
predecessor->GetBlockId()));
} else if (!incoming_try_entry->HasSameExceptionHandlersAs(stored_try_entry)) {
AddError(StringPrintf("Block %d has try entry %s:%d which is not consistent "
"with %s:%d that follows from predecessor %d.",
block->GetBlockId(),
stored_try_entry.DebugName(),
stored_try_entry.GetId(),
incoming_try_entry->DebugName(),
incoming_try_entry->GetId(),
predecessor->GetBlockId()));
}
} else if (incoming_try_entry != nullptr) {
AddError(StringPrintf("Block %d is not a try block but try entry %s:%d follows "
"from predecessor %d.",
block->GetBlockId(),
incoming_try_entry->DebugName(),
incoming_try_entry->GetId(),
predecessor->GetBlockId()));
}
}
}
if (block->IsLoopHeader()) {
HandleLoop(block);
}
}
void GraphChecker::VisitBoundsCheck(HBoundsCheck* check) {
if (!GetGraph()->HasBoundsChecks()) {
AddError(StringPrintf("Instruction %s:%d is a HBoundsCheck, "
"but HasBoundsChecks() returns false",
check->DebugName(),
check->GetId()));
}
// Perform the instruction base checks too.
VisitInstruction(check);
}
void GraphChecker::VisitDeoptimize(HDeoptimize* deopt) {
if (GetGraph()->IsCompilingOsr()) {
AddError(StringPrintf("A graph compiled OSR cannot have a HDeoptimize instruction"));
}
// Perform the instruction base checks too.
VisitInstruction(deopt);
}
void GraphChecker::VisitTryBoundary(HTryBoundary* try_boundary) {
ArrayRef<HBasicBlock* const> handlers = try_boundary->GetExceptionHandlers();
// Ensure that all exception handlers are catch blocks.
// Note that a normal-flow successor may be a catch block before CFG
// simplification. We only test normal-flow successors in GraphChecker.
for (HBasicBlock* handler : handlers) {
if (!handler->IsCatchBlock()) {
AddError(StringPrintf("Block %d with %s:%d has exceptional successor %d which "
"is not a catch block.",
current_block_->GetBlockId(),
try_boundary->DebugName(),
try_boundary->GetId(),
handler->GetBlockId()));
}
}
// Ensure that handlers are not listed multiple times.
for (size_t i = 0, e = handlers.size(); i < e; ++i) {
if (ContainsElement(handlers, handlers[i], i + 1)) {
AddError(StringPrintf("Exception handler block %d of %s:%d is listed multiple times.",
handlers[i]->GetBlockId(),
try_boundary->DebugName(),
try_boundary->GetId()));
}
}
VisitInstruction(try_boundary);
}
void GraphChecker::VisitLoadException(HLoadException* load) {
// Ensure that LoadException is the first instruction in a catch block.
if (!load->GetBlock()->IsCatchBlock()) {
AddError(StringPrintf("%s:%d is in a non-catch block %d.",
load->DebugName(),
load->GetId(),
load->GetBlock()->GetBlockId()));
} else if (load->GetBlock()->GetFirstInstruction() != load) {
AddError(StringPrintf("%s:%d is not the first instruction in catch block %d.",
load->DebugName(),
load->GetId(),
load->GetBlock()->GetBlockId()));
}
}
void GraphChecker::VisitInstruction(HInstruction* instruction) {
if (seen_ids_.IsBitSet(instruction->GetId())) {
AddError(StringPrintf("Instruction id %d is duplicate in graph.",
instruction->GetId()));
} else {
seen_ids_.SetBit(instruction->GetId());
}
// Ensure `instruction` is associated with `current_block_`.
if (instruction->GetBlock() == nullptr) {
AddError(StringPrintf("%s %d in block %d not associated with any block.",
instruction->IsPhi() ? "Phi" : "Instruction",
instruction->GetId(),
current_block_->GetBlockId()));
} else if (instruction->GetBlock() != current_block_) {
AddError(StringPrintf("%s %d in block %d associated with block %d.",
instruction->IsPhi() ? "Phi" : "Instruction",
instruction->GetId(),
current_block_->GetBlockId(),
instruction->GetBlock()->GetBlockId()));
}
// Ensure the inputs of `instruction` are defined in a block of the graph.
for (HInstruction* input : instruction->GetInputs()) {
const HInstructionList& list = input->IsPhi()
? input->GetBlock()->GetPhis()
: input->GetBlock()->GetInstructions();
if (!list.Contains(input)) {
AddError(StringPrintf("Input %d of instruction %d is not defined "
"in a basic block of the control-flow graph.",
input->GetId(),
instruction->GetId()));
}
}
// Ensure the uses of `instruction` are defined in a block of the graph,
// and the entry in the use list is consistent.
for (const HUseListNode<HInstruction*>& use : instruction->GetUses()) {
HInstruction* user = use.GetUser();
const HInstructionList& list = user->IsPhi()
? user->GetBlock()->GetPhis()
: user->GetBlock()->GetInstructions();
if (!list.Contains(user)) {
AddError(StringPrintf("User %s:%d of instruction %d is not defined "
"in a basic block of the control-flow graph.",
user->DebugName(),
user->GetId(),
instruction->GetId()));
}
size_t use_index = use.GetIndex();
HConstInputsRef user_inputs = user->GetInputs();
if ((use_index >= user_inputs.size()) || (user_inputs[use_index] != instruction)) {
AddError(StringPrintf("User %s:%d of instruction %s:%d has a wrong "
"UseListNode index.",
user->DebugName(),
user->GetId(),
instruction->DebugName(),
instruction->GetId()));
}
}
// Ensure the environment uses entries are consistent.
for (const HUseListNode<HEnvironment*>& use : instruction->GetEnvUses()) {
HEnvironment* user = use.GetUser();
size_t use_index = use.GetIndex();
if ((use_index >= user->Size()) || (user->GetInstructionAt(use_index) != instruction)) {
AddError(StringPrintf("Environment user of %s:%d has a wrong "
"UseListNode index.",
instruction->DebugName(),
instruction->GetId()));
}
}
// Ensure 'instruction' has pointers to its inputs' use entries.
auto&& input_records = instruction->GetInputRecords();
for (size_t i = 0; i < input_records.size(); ++i) {
const HUserRecord<HInstruction*>& input_record = input_records[i];
HInstruction* input = input_record.GetInstruction();
if ((input_record.GetBeforeUseNode() == input->GetUses().end()) ||
(input_record.GetUseNode() == input->GetUses().end()) ||
!input->GetUses().ContainsNode(*input_record.GetUseNode()) ||
(input_record.GetUseNode()->GetIndex() != i)) {
AddError(StringPrintf("Instruction %s:%d has an invalid iterator before use entry "
"at input %u (%s:%d).",
instruction->DebugName(),
instruction->GetId(),
static_cast<unsigned>(i),
input->DebugName(),
input->GetId()));
}
}
// Ensure an instruction dominates all its uses.
for (const HUseListNode<HInstruction*>& use : instruction->GetUses()) {
HInstruction* user = use.GetUser();
if (!user->IsPhi() && !instruction->StrictlyDominates(user)) {
AddError(StringPrintf("Instruction %s:%d in block %d does not dominate "
"use %s:%d in block %d.",
instruction->DebugName(),
instruction->GetId(),
current_block_->GetBlockId(),
user->DebugName(),
user->GetId(),
user->GetBlock()->GetBlockId()));
}
}
if (instruction->NeedsEnvironment() && !instruction->HasEnvironment()) {
AddError(StringPrintf("Instruction %s:%d in block %d requires an environment "
"but does not have one.",
instruction->DebugName(),
instruction->GetId(),
current_block_->GetBlockId()));
}
// Ensure an instruction having an environment is dominated by the
// instructions contained in the environment.
for (HEnvironment* environment = instruction->GetEnvironment();
environment != nullptr;
environment = environment->GetParent()) {
for (size_t i = 0, e = environment->Size(); i < e; ++i) {
HInstruction* env_instruction = environment->GetInstructionAt(i);
if (env_instruction != nullptr
&& !env_instruction->StrictlyDominates(instruction)) {
AddError(StringPrintf("Instruction %d in environment of instruction %d "
"from block %d does not dominate instruction %d.",
env_instruction->GetId(),
instruction->GetId(),
current_block_->GetBlockId(),
instruction->GetId()));
}
}
}
// Ensure that reference type instructions have reference type info.
if (instruction->GetType() == Primitive::kPrimNot) {
if (!instruction->GetReferenceTypeInfo().IsValid()) {
AddError(StringPrintf("Reference type instruction %s:%d does not have "
"valid reference type information.",
instruction->DebugName(),
instruction->GetId()));
}
}
if (instruction->CanThrowIntoCatchBlock()) {
// Find the top-level environment. This corresponds to the environment of
// the catch block since we do not inline methods with try/catch.
HEnvironment* environment = instruction->GetEnvironment();
while (environment->GetParent() != nullptr) {
environment = environment->GetParent();
}
// Find all catch blocks and test that `instruction` has an environment
// value for each one.
const HTryBoundary& entry = instruction->GetBlock()->GetTryCatchInformation()->GetTryEntry();
for (HBasicBlock* catch_block : entry.GetExceptionHandlers()) {
for (HInstructionIterator phi_it(catch_block->GetPhis()); !phi_it.Done(); phi_it.Advance()) {
HPhi* catch_phi = phi_it.Current()->AsPhi();
if (environment->GetInstructionAt(catch_phi->GetRegNumber()) == nullptr) {
AddError(StringPrintf("Instruction %s:%d throws into catch block %d "
"with catch phi %d for vreg %d but its "
"corresponding environment slot is empty.",
instruction->DebugName(),
instruction->GetId(),
catch_block->GetBlockId(),
catch_phi->GetId(),
catch_phi->GetRegNumber()));
}
}
}
}
}
void GraphChecker::VisitInvokeStaticOrDirect(HInvokeStaticOrDirect* invoke) {
VisitInstruction(invoke);
if (invoke->IsStaticWithExplicitClinitCheck()) {
const HInstruction* last_input = invoke->GetInputs().back();
if (last_input == nullptr) {
AddError(StringPrintf("Static invoke %s:%d marked as having an explicit clinit check "
"has a null pointer as last input.",
invoke->DebugName(),
invoke->GetId()));
}
if (!last_input->IsClinitCheck() && !last_input->IsLoadClass()) {
AddError(StringPrintf("Static invoke %s:%d marked as having an explicit clinit check "
"has a last instruction (%s:%d) which is neither a clinit check "
"nor a load class instruction.",
invoke->DebugName(),
invoke->GetId(),
last_input->DebugName(),
last_input->GetId()));
}
}
}
void GraphChecker::VisitReturn(HReturn* ret) {
VisitInstruction(ret);
HBasicBlock* successor = ret->GetBlock()->GetSingleSuccessor();
if (!successor->IsExitBlock() && !IsExitTryBoundaryIntoExitBlock(successor)) {
AddError(StringPrintf("%s:%d does not jump to the exit block.",
ret->DebugName(),
ret->GetId()));
}
}
void GraphChecker::VisitReturnVoid(HReturnVoid* ret) {
VisitInstruction(ret);
HBasicBlock* successor = ret->GetBlock()->GetSingleSuccessor();
if (!successor->IsExitBlock() && !IsExitTryBoundaryIntoExitBlock(successor)) {
AddError(StringPrintf("%s:%d does not jump to the exit block.",
ret->DebugName(),
ret->GetId()));
}
}
void GraphChecker::VisitCheckCast(HCheckCast* check) {
VisitInstruction(check);
HInstruction* input = check->InputAt(1);
if (!input->IsLoadClass()) {
AddError(StringPrintf("%s:%d expects a HLoadClass as second input, not %s:%d.",
check->DebugName(),
check->GetId(),
input->DebugName(),
input->GetId()));
}
}
void GraphChecker::VisitInstanceOf(HInstanceOf* instruction) {
VisitInstruction(instruction);
HInstruction* input = instruction->InputAt(1);
if (!input->IsLoadClass()) {
AddError(StringPrintf("%s:%d expects a HLoadClass as second input, not %s:%d.",
instruction->DebugName(),
instruction->GetId(),
input->DebugName(),
input->GetId()));
}
}
void GraphChecker::HandleLoop(HBasicBlock* loop_header) {
int id = loop_header->GetBlockId();
HLoopInformation* loop_information = loop_header->GetLoopInformation();
if (loop_information->GetPreHeader()->GetSuccessors().size() != 1) {
AddError(StringPrintf(
"Loop pre-header %d of loop defined by header %d has %zu successors.",
loop_information->GetPreHeader()->GetBlockId(),
id,
loop_information->GetPreHeader()->GetSuccessors().size()));
}
if (loop_information->GetSuspendCheck() == nullptr) {
AddError(StringPrintf(
"Loop with header %d does not have a suspend check.",
loop_header->GetBlockId()));
}
if (loop_information->GetSuspendCheck() != loop_header->GetFirstInstructionDisregardMoves()) {
AddError(StringPrintf(
"Loop header %d does not have the loop suspend check as the first instruction.",
loop_header->GetBlockId()));
}
// Ensure the loop header has only one incoming branch and the remaining
// predecessors are back edges.
size_t num_preds = loop_header->GetPredecessors().size();
if (num_preds < 2) {
AddError(StringPrintf(
"Loop header %d has less than two predecessors: %zu.",
id,
num_preds));
} else {
HBasicBlock* first_predecessor = loop_header->GetPredecessors()[0];
if (loop_information->IsBackEdge(*first_predecessor)) {
AddError(StringPrintf(
"First predecessor of loop header %d is a back edge.",
id));
}
for (size_t i = 1, e = loop_header->GetPredecessors().size(); i < e; ++i) {
HBasicBlock* predecessor = loop_header->GetPredecessors()[i];
if (!loop_information->IsBackEdge(*predecessor)) {
AddError(StringPrintf(
"Loop header %d has multiple incoming (non back edge) blocks: %d.",
id,
predecessor->GetBlockId()));
}
}
}
const ArenaBitVector& loop_blocks = loop_information->GetBlocks();
// Ensure back edges belong to the loop.
if (loop_information->NumberOfBackEdges() == 0) {
AddError(StringPrintf(
"Loop defined by header %d has no back edge.",
id));
} else {
for (HBasicBlock* back_edge : loop_information->GetBackEdges()) {
int back_edge_id = back_edge->GetBlockId();
if (!loop_blocks.IsBitSet(back_edge_id)) {
AddError(StringPrintf(
"Loop defined by header %d has an invalid back edge %d.",
id,
back_edge_id));
} else if (back_edge->GetLoopInformation() != loop_information) {
AddError(StringPrintf(
"Back edge %d of loop defined by header %d belongs to nested loop "
"with header %d.",
back_edge_id,
id,
back_edge->GetLoopInformation()->GetHeader()->GetBlockId()));
}
}
}
// If this is a nested loop, ensure the outer loops contain a superset of the blocks.
for (HLoopInformationOutwardIterator it(*loop_header); !it.Done(); it.Advance()) {
HLoopInformation* outer_info = it.Current();
if (!loop_blocks.IsSubsetOf(&outer_info->GetBlocks())) {
AddError(StringPrintf("Blocks of loop defined by header %d are not a subset of blocks of "
"an outer loop defined by header %d.",
id,
outer_info->GetHeader()->GetBlockId()));
}
}
// Ensure the pre-header block is first in the list of predecessors of a loop
// header and that the header block is its only successor.
if (!loop_header->IsLoopPreHeaderFirstPredecessor()) {
AddError(StringPrintf(
"Loop pre-header is not the first predecessor of the loop header %d.",
id));
}
// Ensure all blocks in the loop are live and dominated by the loop header in
// the case of natural loops.
for (uint32_t i : loop_blocks.Indexes()) {
HBasicBlock* loop_block = GetGraph()->GetBlocks()[i];
if (loop_block == nullptr) {
AddError(StringPrintf("Loop defined by header %d contains a previously removed block %d.",
id,
i));
} else if (!loop_information->IsIrreducible() && !loop_header->Dominates(loop_block)) {
AddError(StringPrintf("Loop block %d not dominated by loop header %d.",
i,
id));
}
}
}
static bool IsSameSizeConstant(const HInstruction* insn1, const HInstruction* insn2) {
return insn1->IsConstant()
&& insn2->IsConstant()
&& Primitive::Is64BitType(insn1->GetType()) == Primitive::Is64BitType(insn2->GetType());
}
static bool IsConstantEquivalent(const HInstruction* insn1,
const HInstruction* insn2,
BitVector* visited) {
if (insn1->IsPhi() &&
insn1->AsPhi()->IsVRegEquivalentOf(insn2)) {
HConstInputsRef insn1_inputs = insn1->GetInputs();
HConstInputsRef insn2_inputs = insn2->GetInputs();
if (insn1_inputs.size() != insn2_inputs.size()) {
return false;
}
// Testing only one of the two inputs for recursion is sufficient.
if (visited->IsBitSet(insn1->GetId())) {
return true;
}
visited->SetBit(insn1->GetId());
for (size_t i = 0; i < insn1_inputs.size(); ++i) {
if (!IsConstantEquivalent(insn1_inputs[i], insn2_inputs[i], visited)) {
return false;
}
}
return true;
} else if (IsSameSizeConstant(insn1, insn2)) {
return insn1->AsConstant()->GetValueAsUint64() == insn2->AsConstant()->GetValueAsUint64();
} else {
return false;
}
}
void GraphChecker::VisitPhi(HPhi* phi) {
VisitInstruction(phi);
// Ensure the first input of a phi is not itself.
ArrayRef<HUserRecord<HInstruction*>> input_records = phi->GetInputRecords();
if (input_records[0].GetInstruction() == phi) {
AddError(StringPrintf("Loop phi %d in block %d is its own first input.",
phi->GetId(),
phi->GetBlock()->GetBlockId()));
}
// Ensure that the inputs have the same primitive kind as the phi.
for (size_t i = 0; i < input_records.size(); ++i) {
HInstruction* input = input_records[i].GetInstruction();
if (Primitive::PrimitiveKind(input->GetType()) != Primitive::PrimitiveKind(phi->GetType())) {
AddError(StringPrintf(
"Input %d at index %zu of phi %d from block %d does not have the "
"same kind as the phi: %s versus %s",
input->GetId(), i, phi->GetId(), phi->GetBlock()->GetBlockId(),
Primitive::PrettyDescriptor(input->GetType()),
Primitive::PrettyDescriptor(phi->GetType())));
}
}
if (phi->GetType() != HPhi::ToPhiType(phi->GetType())) {
AddError(StringPrintf("Phi %d in block %d does not have an expected phi type: %s",
phi->GetId(),
phi->GetBlock()->GetBlockId(),
Primitive::PrettyDescriptor(phi->GetType())));
}
if (phi->IsCatchPhi()) {
// The number of inputs of a catch phi should be the total number of throwing
// instructions caught by this catch block. We do not enforce this, however,
// because we do not remove the corresponding inputs when we prove that an
// instruction cannot throw. Instead, we at least test that all phis have the
// same, non-zero number of inputs (b/24054676).
if (input_records.empty()) {
AddError(StringPrintf("Phi %d in catch block %d has zero inputs.",
phi->GetId(),
phi->GetBlock()->GetBlockId()));
} else {
HInstruction* next_phi = phi->GetNext();
if (next_phi != nullptr) {
size_t input_count_next = next_phi->InputCount();
if (input_records.size() != input_count_next) {
AddError(StringPrintf("Phi %d in catch block %d has %zu inputs, "
"but phi %d has %zu inputs.",
phi->GetId(),
phi->GetBlock()->GetBlockId(),
input_records.size(),
next_phi->GetId(),
input_count_next));
}
}
}
} else {
// Ensure the number of inputs of a non-catch phi is the same as the number
// of its predecessors.
const ArenaVector<HBasicBlock*>& predecessors = phi->GetBlock()->GetPredecessors();
if (input_records.size() != predecessors.size()) {
AddError(StringPrintf(
"Phi %d in block %d has %zu inputs, "
"but block %d has %zu predecessors.",
phi->GetId(), phi->GetBlock()->GetBlockId(), input_records.size(),
phi->GetBlock()->GetBlockId(), predecessors.size()));
} else {
// Ensure phi input at index I either comes from the Ith
// predecessor or from a block that dominates this predecessor.
for (size_t i = 0; i < input_records.size(); ++i) {
HInstruction* input = input_records[i].GetInstruction();
HBasicBlock* predecessor = predecessors[i];
if (!(input->GetBlock() == predecessor
|| input->GetBlock()->Dominates(predecessor))) {
AddError(StringPrintf(
"Input %d at index %zu of phi %d from block %d is not defined in "
"predecessor number %zu nor in a block dominating it.",
input->GetId(), i, phi->GetId(), phi->GetBlock()->GetBlockId(),
i));
}
}
}
}
// Ensure that catch phis are sorted by their vreg number, as required by
// the register allocator and code generator. This does not apply to normal
// phis which can be constructed artifically.
if (phi->IsCatchPhi()) {
HInstruction* next_phi = phi->GetNext();
if (next_phi != nullptr && phi->GetRegNumber() > next_phi->AsPhi()->GetRegNumber()) {
AddError(StringPrintf("Catch phis %d and %d in block %d are not sorted by their "
"vreg numbers.",
phi->GetId(),
next_phi->GetId(),
phi->GetBlock()->GetBlockId()));
}
}
// Test phi equivalents. There should not be two of the same type and they should only be
// created for constants which were untyped in DEX. Note that this test can be skipped for
// a synthetic phi (indicated by lack of a virtual register).
if (phi->GetRegNumber() != kNoRegNumber) {
for (HInstructionIterator phi_it(phi->GetBlock()->GetPhis());
!phi_it.Done();
phi_it.Advance()) {
HPhi* other_phi = phi_it.Current()->AsPhi();
if (phi != other_phi && phi->GetRegNumber() == other_phi->GetRegNumber()) {
if (phi->GetType() == other_phi->GetType()) {
std::stringstream type_str;
type_str << phi->GetType();
AddError(StringPrintf("Equivalent phi (%d) found for VReg %d with type: %s.",
phi->GetId(),
phi->GetRegNumber(),
type_str.str().c_str()));
} else if (phi->GetType() == Primitive::kPrimNot) {
std::stringstream type_str;
type_str << other_phi->GetType();
AddError(StringPrintf(
"Equivalent non-reference phi (%d) found for VReg %d with type: %s.",
phi->GetId(),
phi->GetRegNumber(),
type_str.str().c_str()));
} else {
// If we get here, make sure we allocate all the necessary storage at once
// because the BitVector reallocation strategy has very bad worst-case behavior.
ArenaBitVector& visited = visited_storage_;
visited.SetBit(GetGraph()->GetCurrentInstructionId());
visited.ClearAllBits();
if (!IsConstantEquivalent(phi, other_phi, &visited)) {
AddError(StringPrintf("Two phis (%d and %d) found for VReg %d but they "
"are not equivalents of constants.",
phi->GetId(),
other_phi->GetId(),
phi->GetRegNumber()));
}
}
}
}
}
}
void GraphChecker::HandleBooleanInput(HInstruction* instruction, size_t input_index) {
HInstruction* input = instruction->InputAt(input_index);
if (input->IsIntConstant()) {
int32_t value = input->AsIntConstant()->GetValue();
if (value != 0 && value != 1) {
AddError(StringPrintf(
"%s instruction %d has a non-Boolean constant input %d whose value is: %d.",
instruction->DebugName(),
instruction->GetId(),
static_cast<int>(input_index),
value));
}
} else if (Primitive::PrimitiveKind(input->GetType()) != Primitive::kPrimInt) {
// TODO: We need a data-flow analysis to determine if an input like Phi,
// Select or a binary operation is actually Boolean. Allow for now.
AddError(StringPrintf(
"%s instruction %d has a non-integer input %d whose type is: %s.",
instruction->DebugName(),
instruction->GetId(),
static_cast<int>(input_index),
Primitive::PrettyDescriptor(input->GetType())));
}
}
void GraphChecker::VisitPackedSwitch(HPackedSwitch* instruction) {
VisitInstruction(instruction);
// Check that the number of block successors matches the switch count plus
// one for the default block.
HBasicBlock* block = instruction->GetBlock();
if (instruction->GetNumEntries() + 1u != block->GetSuccessors().size()) {
AddError(StringPrintf(
"%s instruction %d in block %d expects %u successors to the block, but found: %zu.",
instruction->DebugName(),
instruction->GetId(),
block->GetBlockId(),
instruction->GetNumEntries() + 1u,
block->GetSuccessors().size()));
}
}
void GraphChecker::VisitIf(HIf* instruction) {
VisitInstruction(instruction);
HandleBooleanInput(instruction, 0);
}
void GraphChecker::VisitSelect(HSelect* instruction) {
VisitInstruction(instruction);
HandleBooleanInput(instruction, 2);
}
void GraphChecker::VisitBooleanNot(HBooleanNot* instruction) {
VisitInstruction(instruction);
HandleBooleanInput(instruction, 0);
}
void GraphChecker::VisitCondition(HCondition* op) {
VisitInstruction(op);
if (op->GetType() != Primitive::kPrimBoolean) {
AddError(StringPrintf(
"Condition %s %d has a non-Boolean result type: %s.",
op->DebugName(), op->GetId(),
Primitive::PrettyDescriptor(op->GetType())));
}
HInstruction* lhs = op->InputAt(0);
HInstruction* rhs = op->InputAt(1);
if (Primitive::PrimitiveKind(lhs->GetType()) != Primitive::PrimitiveKind(rhs->GetType())) {
AddError(StringPrintf(
"Condition %s %d has inputs of different kinds: %s, and %s.",
op->DebugName(), op->GetId(),
Primitive::PrettyDescriptor(lhs->GetType()),
Primitive::PrettyDescriptor(rhs->GetType())));
}
if (!op->IsEqual() && !op->IsNotEqual()) {
if ((lhs->GetType() == Primitive::kPrimNot)) {
AddError(StringPrintf(
"Condition %s %d uses an object as left-hand side input.",
op->DebugName(), op->GetId()));
} else if (rhs->GetType() == Primitive::kPrimNot) {
AddError(StringPrintf(
"Condition %s %d uses an object as right-hand side input.",
op->DebugName(), op->GetId()));
}
}
}
void GraphChecker::VisitNeg(HNeg* instruction) {
VisitInstruction(instruction);
Primitive::Type input_type = instruction->InputAt(0)->GetType();
Primitive::Type result_type = instruction->GetType();
if (result_type != Primitive::PrimitiveKind(input_type)) {
AddError(StringPrintf("Binary operation %s %d has a result type different "
"from its input kind: %s vs %s.",
instruction->DebugName(), instruction->GetId(),
Primitive::PrettyDescriptor(result_type),
Primitive::PrettyDescriptor(input_type)));
}
}
void GraphChecker::VisitBinaryOperation(HBinaryOperation* op) {
VisitInstruction(op);
Primitive::Type lhs_type = op->InputAt(0)->GetType();
Primitive::Type rhs_type = op->InputAt(1)->GetType();
Primitive::Type result_type = op->GetType();
// Type consistency between inputs.
if (op->IsUShr() || op->IsShr() || op->IsShl() || op->IsRor()) {
if (Primitive::PrimitiveKind(rhs_type) != Primitive::kPrimInt) {
AddError(StringPrintf("Shift/rotate operation %s %d has a non-int kind second input: "
"%s of type %s.",
op->DebugName(), op->GetId(),
op->InputAt(1)->DebugName(),
Primitive::PrettyDescriptor(rhs_type)));
}
} else {
if (Primitive::PrimitiveKind(lhs_type) != Primitive::PrimitiveKind(rhs_type)) {
AddError(StringPrintf("Binary operation %s %d has inputs of different kinds: %s, and %s.",
op->DebugName(), op->GetId(),
Primitive::PrettyDescriptor(lhs_type),
Primitive::PrettyDescriptor(rhs_type)));
}
}
// Type consistency between result and input(s).
if (op->IsCompare()) {
if (result_type != Primitive::kPrimInt) {
AddError(StringPrintf("Compare operation %d has a non-int result type: %s.",
op->GetId(),
Primitive::PrettyDescriptor(result_type)));
}
} else if (op->IsUShr() || op->IsShr() || op->IsShl() || op->IsRor()) {
// Only check the first input (value), as the second one (distance)
// must invariably be of kind `int`.
if (result_type != Primitive::PrimitiveKind(lhs_type)) {
AddError(StringPrintf("Shift/rotate operation %s %d has a result type different "
"from its left-hand side (value) input kind: %s vs %s.",
op->DebugName(), op->GetId(),
Primitive::PrettyDescriptor(result_type),
Primitive::PrettyDescriptor(lhs_type)));
}
} else {
if (Primitive::PrimitiveKind(result_type) != Primitive::PrimitiveKind(lhs_type)) {
AddError(StringPrintf("Binary operation %s %d has a result kind different "
"from its left-hand side input kind: %s vs %s.",
op->DebugName(), op->GetId(),
Primitive::PrettyDescriptor(result_type),
Primitive::PrettyDescriptor(lhs_type)));
}
if (Primitive::PrimitiveKind(result_type) != Primitive::PrimitiveKind(rhs_type)) {
AddError(StringPrintf("Binary operation %s %d has a result kind different "
"from its right-hand side input kind: %s vs %s.",
op->DebugName(), op->GetId(),
Primitive::PrettyDescriptor(result_type),
Primitive::PrettyDescriptor(rhs_type)));
}
}
}
void GraphChecker::VisitConstant(HConstant* instruction) {
HBasicBlock* block = instruction->GetBlock();
if (!block->IsEntryBlock()) {
AddError(StringPrintf(
"%s %d should be in the entry block but is in block %d.",
instruction->DebugName(),
instruction->GetId(),
block->GetBlockId()));
}
}
void GraphChecker::VisitBoundType(HBoundType* instruction) {
VisitInstruction(instruction);
if (!instruction->GetUpperBound().IsValid()) {
AddError(StringPrintf(
"%s %d does not have a valid upper bound RTI.",
instruction->DebugName(),
instruction->GetId()));
}
}
void GraphChecker::VisitTypeConversion(HTypeConversion* instruction) {
VisitInstruction(instruction);
Primitive::Type result_type = instruction->GetResultType();
Primitive::Type input_type = instruction->GetInputType();
// Invariant: We should never generate a conversion to a Boolean value.
if (result_type == Primitive::kPrimBoolean) {
AddError(StringPrintf(
"%s %d converts to a %s (from a %s).",
instruction->DebugName(),
instruction->GetId(),
Primitive::PrettyDescriptor(result_type),
Primitive::PrettyDescriptor(input_type)));
}
}
} // namespace art