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/*
* Copyright (C) 2011 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.
*/
#ifndef ART_RUNTIME_VERIFIER_METHOD_VERIFIER_H_
#define ART_RUNTIME_VERIFIER_METHOD_VERIFIER_H_
#include <memory>
#include <sstream>
#include <vector>
#include <android-base/logging.h>
#include "base/arena_allocator.h"
#include "base/macros.h"
#include "base/scoped_arena_containers.h"
#include "base/value_object.h"
#include "dex/code_item_accessors.h"
#include "dex/dex_file_types.h"
#include "dex/method_reference.h"
#include "handle.h"
#include "instruction_flags.h"
#include "reg_type_cache.h"
#include "register_line.h"
#include "verifier_enums.h"
namespace art {
class ClassLinker;
class CompilerCallbacks;
class DexFile;
class Instruction;
struct ReferenceMap2Visitor;
class Thread;
class VariableIndentationOutputStream;
namespace dex {
struct ClassDef;
struct CodeItem;
} // namespace dex
namespace mirror {
class DexCache;
} // namespace mirror
namespace verifier {
class MethodVerifier;
class RegisterLine;
using RegisterLineArenaUniquePtr = std::unique_ptr<RegisterLine, RegisterLineArenaDelete>;
class RegType;
struct ScopedNewLine;
// We don't need to store the register data for many instructions, because we either only need
// it at branch points (for verification) or GC points and branches (for verification +
// type-precise register analysis).
enum RegisterTrackingMode {
kTrackRegsBranches,
kTrackCompilerInterestPoints,
kTrackRegsAll,
};
// A mapping from a dex pc to the register line statuses as they are immediately prior to the
// execution of that instruction.
class PcToRegisterLineTable {
public:
explicit PcToRegisterLineTable(ScopedArenaAllocator& allocator);
~PcToRegisterLineTable();
// Initialize the RegisterTable. Every instruction address can have a different set of information
// about what's in which register, but for verification purposes we only need to store it at
// branch target addresses (because we merge into that).
void Init(RegisterTrackingMode mode,
InstructionFlags* flags,
uint32_t insns_size,
uint16_t registers_size,
ScopedArenaAllocator& allocator,
RegTypeCache* reg_types);
bool IsInitialized() const {
return !register_lines_.empty();
}
RegisterLine* GetLine(size_t idx) const {
return register_lines_[idx].get();
}
private:
ScopedArenaVector<RegisterLineArenaUniquePtr> register_lines_;
DISALLOW_COPY_AND_ASSIGN(PcToRegisterLineTable);
};
// The verifier
class MethodVerifier {
public:
static MethodVerifier* VerifyMethodAndDump(Thread* self,
VariableIndentationOutputStream* vios,
uint32_t method_idx,
const DexFile* dex_file,
Handle<mirror::DexCache> dex_cache,
Handle<mirror::ClassLoader> class_loader,
const dex::ClassDef& class_def,
const dex::CodeItem* code_item, ArtMethod* method,
uint32_t method_access_flags,
uint32_t api_level)
REQUIRES_SHARED(Locks::mutator_lock_);
// Calculates the verification information for every instruction of the given method. The given
// dex-cache and class-loader will be used for lookups. No classes will be loaded. If verification
// fails hard nullptr will be returned. This should only be used if one needs to examine what the
// verifier believes about the registers of a given method.
static MethodVerifier* CalculateVerificationInfo(Thread* self,
ArtMethod* method,
Handle<mirror::DexCache> dex_cache,
Handle<mirror::ClassLoader> class_loader)
REQUIRES_SHARED(Locks::mutator_lock_);
const DexFile& GetDexFile() const {
DCHECK(dex_file_ != nullptr);
return *dex_file_;
}
RegTypeCache* GetRegTypeCache() {
return &reg_types_;
}
// Log a verification failure.
std::ostream& Fail(VerifyError error, bool pending_exc = true);
// Log for verification information.
ScopedNewLine LogVerifyInfo();
// Information structure for a lock held at a certain point in time.
struct DexLockInfo {
// The registers aliasing the lock.
std::set<uint32_t> dex_registers;
// The dex PC of the monitor-enter instruction.
uint32_t dex_pc;
explicit DexLockInfo(uint32_t dex_pc_in) {
dex_pc = dex_pc_in;
}
};
// Fills 'monitor_enter_dex_pcs' with the dex pcs of the monitor-enter instructions corresponding
// to the locks held at 'dex_pc' in method 'm'.
// Note: this is the only situation where the verifier will visit quickened instructions.
static void FindLocksAtDexPc(ArtMethod* m,
uint32_t dex_pc,
std::vector<DexLockInfo>* monitor_enter_dex_pcs,
uint32_t api_level)
REQUIRES_SHARED(Locks::mutator_lock_);
static void Init(ClassLinker* class_linker) REQUIRES_SHARED(Locks::mutator_lock_);
static void Shutdown();
virtual ~MethodVerifier();
static void VisitStaticRoots(RootVisitor* visitor)
REQUIRES_SHARED(Locks::mutator_lock_);
void VisitRoots(RootVisitor* visitor, const RootInfo& roots)
REQUIRES_SHARED(Locks::mutator_lock_);
// Accessors used by the compiler via CompilerCallback
const CodeItemDataAccessor& CodeItem() const {
return code_item_accessor_;
}
RegisterLine* GetRegLine(uint32_t dex_pc);
ALWAYS_INLINE const InstructionFlags& GetInstructionFlags(size_t index) const;
MethodReference GetMethodReference() const;
bool HasCheckCasts() const;
bool HasFailures() const;
bool HasInstructionThatWillThrow() const {
return flags_.have_any_pending_runtime_throw_failure_;
}
virtual const RegType& ResolveCheckedClass(dex::TypeIndex class_idx)
REQUIRES_SHARED(Locks::mutator_lock_) = 0;
uint32_t GetEncounteredFailureTypes() {
return encountered_failure_types_;
}
ClassLinker* GetClassLinker() {
return class_linker_;
}
bool IsAotMode() const {
return flags_.aot_mode_;
}
protected:
MethodVerifier(Thread* self,
ClassLinker* class_linker,
ArenaPool* arena_pool,
const DexFile* dex_file,
const dex::CodeItem* code_item,
uint32_t dex_method_idx,
bool can_load_classes,
bool allow_thread_suspension,
bool allow_soft_failures,
bool aot_mode)
REQUIRES_SHARED(Locks::mutator_lock_);
// Verification result for method(s). Includes a (maximum) failure kind, and (the union of)
// all failure types.
struct FailureData : ValueObject {
FailureKind kind = FailureKind::kNoFailure;
uint32_t types = 0U;
// Merge src into this. Uses the most severe failure kind, and the union of types.
void Merge(const FailureData& src);
};
/*
* Perform verification on a single method.
*
* We do this in three passes:
* (1) Walk through all code units, determining instruction locations,
* widths, and other characteristics.
* (2) Walk through all code units, performing static checks on
* operands.
* (3) Iterate through the method, checking type safety and looking
* for code flow problems.
*/
static FailureData VerifyMethod(Thread* self,
ClassLinker* class_linker,
ArenaPool* arena_pool,
uint32_t method_idx,
const DexFile* dex_file,
Handle<mirror::DexCache> dex_cache,
Handle<mirror::ClassLoader> class_loader,
const dex::ClassDef& class_def_idx,
const dex::CodeItem* code_item,
ArtMethod* method,
uint32_t method_access_flags,
CompilerCallbacks* callbacks,
bool allow_soft_failures,
HardFailLogMode log_level,
bool need_precise_constants,
uint32_t api_level,
bool aot_mode,
std::string* hard_failure_msg)
REQUIRES_SHARED(Locks::mutator_lock_);
template <bool kVerifierDebug>
static FailureData VerifyMethod(Thread* self,
ClassLinker* class_linker,
ArenaPool* arena_pool,
uint32_t method_idx,
const DexFile* dex_file,
Handle<mirror::DexCache> dex_cache,
Handle<mirror::ClassLoader> class_loader,
const dex::ClassDef& class_def_idx,
const dex::CodeItem* code_item,
ArtMethod* method,
uint32_t method_access_flags,
CompilerCallbacks* callbacks,
bool allow_soft_failures,
HardFailLogMode log_level,
bool need_precise_constants,
uint32_t api_level,
bool aot_mode,
std::string* hard_failure_msg)
REQUIRES_SHARED(Locks::mutator_lock_);
// For VerifierDepsTest. TODO: Refactor.
// Run verification on the method. Returns true if verification completes and false if the input
// has an irrecoverable corruption.
virtual bool Verify() REQUIRES_SHARED(Locks::mutator_lock_) = 0;
static MethodVerifier* CreateVerifier(Thread* self,
const DexFile* dex_file,
Handle<mirror::DexCache> dex_cache,
Handle<mirror::ClassLoader> class_loader,
const dex::ClassDef& class_def,
const dex::CodeItem* code_item,
uint32_t method_idx,
ArtMethod* method,
uint32_t access_flags,
bool can_load_classes,
bool allow_soft_failures,
bool need_precise_constants,
bool verify_to_dump,
bool allow_thread_suspension,
uint32_t api_level)
REQUIRES_SHARED(Locks::mutator_lock_);
// The thread we're verifying on.
Thread* const self_;
// Arena allocator.
ArenaStack arena_stack_;
ScopedArenaAllocator allocator_;
RegTypeCache reg_types_;
PcToRegisterLineTable reg_table_;
// Storage for the register status we're currently working on.
RegisterLineArenaUniquePtr work_line_;
// The address of the instruction we're currently working on, note that this is in 2 byte
// quantities
uint32_t work_insn_idx_;
// Storage for the register status we're saving for later.
RegisterLineArenaUniquePtr saved_line_;
const uint32_t dex_method_idx_; // The method we're working on.
const DexFile* const dex_file_; // The dex file containing the method.
const CodeItemDataAccessor code_item_accessor_;
// Instruction widths and flags, one entry per code unit.
// Owned, but not unique_ptr since insn_flags_ are allocated in arenas.
ArenaUniquePtr<InstructionFlags[]> insn_flags_;
// The types of any error that occurs.
std::vector<VerifyError> failures_;
// Error messages associated with failures.
std::vector<std::ostringstream*> failure_messages_;
struct {
// Is there a pending hard failure?
bool have_pending_hard_failure_ : 1;
// Is there a pending runtime throw failure? A runtime throw failure is when an instruction
// would fail at runtime throwing an exception. Such an instruction causes the following code
// to be unreachable. This is set by Fail and used to ensure we don't process unreachable
// instructions that would hard fail the verification.
// Note: this flag is reset after processing each instruction.
bool have_pending_runtime_throw_failure_ : 1;
// Is there a pending experimental failure?
bool have_pending_experimental_failure_ : 1;
// A version of the above that is not reset and thus captures if there were *any* throw
// failures.
bool have_any_pending_runtime_throw_failure_ : 1;
// Verify in AoT mode?
bool aot_mode_ : 1;
} flags_;
// Info message log use primarily for verifier diagnostics.
std::ostringstream info_messages_;
// Bitset of the encountered failure types. Bits are according to the values in VerifyError.
uint32_t encountered_failure_types_;
const bool can_load_classes_;
// Converts soft failures to hard failures when false. Only false when the compiler isn't
// running and the verifier is called from the class linker.
const bool allow_soft_failures_;
// Indicates the method being verified contains at least one check-cast or aput-object
// instruction. Aput-object operations implicitly check for array-store exceptions, similar to
// check-cast.
bool has_check_casts_;
// Classlinker to use when resolving.
ClassLinker* class_linker_;
// Link, for the method verifier root linked list.
MethodVerifier* link_;
friend class art::Thread;
friend class ClassVerifier;
friend class VerifierDepsTest;
DISALLOW_COPY_AND_ASSIGN(MethodVerifier);
};
} // namespace verifier
} // namespace art
#endif // ART_RUNTIME_VERIFIER_METHOD_VERIFIER_H_