/*
* Copyright (C) 2012 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_REGISTER_LINE_H_
#define ART_RUNTIME_VERIFIER_REGISTER_LINE_H_
#include <memory>
#include <vector>
#include <android-base/logging.h>
#include "base/safe_map.h"
#include "base/scoped_arena_containers.h"
namespace art {
class Instruction;
namespace verifier {
class MethodVerifier;
class RegType;
/*
* Register type categories, for type checking.
*
* The spec says category 1 includes boolean, byte, char, short, int, float, reference, and
* returnAddress. Category 2 includes long and double.
*
* We treat object references separately, so we have "category1nr". We don't support jsr/ret, so
* there is no "returnAddress" type.
*/
enum TypeCategory {
kTypeCategoryUnknown = 0,
kTypeCategory1nr = 1, // boolean, byte, char, short, int, float
kTypeCategory2 = 2, // long, double
kTypeCategoryRef = 3, // object reference
};
// What to do with the lock levels when setting the register type.
enum class LockOp {
kClear, // Clear the lock levels recorded.
kKeep // Leave the lock levels alone.
};
// During verification, we associate one of these with every "interesting" instruction. We track
// the status of all registers, and (if the method has any monitor-enter instructions) maintain a
// stack of entered monitors (identified by code unit offset).
class RegisterLine {
public:
// A map from register to a bit vector of indices into the monitors_ stack.
using RegToLockDepthsMap = ScopedArenaSafeMap<uint32_t, uint32_t>;
// Create a register line of num_regs registers.
static RegisterLine* Create(size_t num_regs, MethodVerifier* verifier);
// Implement category-1 "move" instructions. Copy a 32-bit value from "vsrc" to "vdst".
void CopyRegister1(MethodVerifier* verifier, uint32_t vdst, uint32_t vsrc, TypeCategory cat)
REQUIRES_SHARED(Locks::mutator_lock_);
// Implement category-2 "move" instructions. Copy a 64-bit value from "vsrc" to "vdst". This
// copies both halves of the register.
void CopyRegister2(MethodVerifier* verifier, uint32_t vdst, uint32_t vsrc)
REQUIRES_SHARED(Locks::mutator_lock_);
// Implement "move-result". Copy the category-1 value from the result register to another
// register, and reset the result register.
void CopyResultRegister1(MethodVerifier* verifier, uint32_t vdst, bool is_reference)
REQUIRES_SHARED(Locks::mutator_lock_);
// Implement "move-result-wide". Copy the category-2 value from the result register to another
// register, and reset the result register.
void CopyResultRegister2(MethodVerifier* verifier, uint32_t vdst)
REQUIRES_SHARED(Locks::mutator_lock_);
// Set the invisible result register to unknown
void SetResultTypeToUnknown(MethodVerifier* verifier) REQUIRES_SHARED(Locks::mutator_lock_);
// Set the type of register N, verifying that the register is valid. If "newType" is the "Lo"
// part of a 64-bit value, register N+1 will be set to "newType+1".
// The register index was validated during the static pass, so we don't need to check it here.
//
// LockOp::kClear should be used by default; it will clear the lock levels associated with the
// register. An example is setting the register type because an instruction writes to the
// register.
// LockOp::kKeep keeps the lock levels of the register and only changes the register type. This
// is typical when the underlying value did not change, but we have "different" type information
// available now. An example is sharpening types after a check-cast. Note that when given kKeep,
// the new_type is dchecked to be a reference type.
template <LockOp kLockOp>
ALWAYS_INLINE bool SetRegisterType(MethodVerifier* verifier,
uint32_t vdst,
const RegType& new_type)
REQUIRES_SHARED(Locks::mutator_lock_);
bool SetRegisterTypeWide(MethodVerifier* verifier,
uint32_t vdst,
const RegType& new_type1,
const RegType& new_type2)
REQUIRES_SHARED(Locks::mutator_lock_);
/* Set the type of the "result" register. */
void SetResultRegisterType(MethodVerifier* verifier, const RegType& new_type)
REQUIRES_SHARED(Locks::mutator_lock_);
void SetResultRegisterTypeWide(const RegType& new_type1, const RegType& new_type2)
REQUIRES_SHARED(Locks::mutator_lock_);
// Get the type of register vsrc.
const RegType& GetRegisterType(MethodVerifier* verifier, uint32_t vsrc) const;
ALWAYS_INLINE bool VerifyRegisterType(MethodVerifier* verifier,
uint32_t vsrc,
const RegType& check_type)
REQUIRES_SHARED(Locks::mutator_lock_);
bool VerifyRegisterTypeWide(MethodVerifier* verifier,
uint32_t vsrc,
const RegType& check_type1,
const RegType& check_type2)
REQUIRES_SHARED(Locks::mutator_lock_);
void CopyFromLine(const RegisterLine* src) {
DCHECK_EQ(num_regs_, src->num_regs_);
memcpy(&line_, &src->line_, num_regs_ * sizeof(uint16_t));
monitors_ = src->monitors_;
reg_to_lock_depths_ = src->reg_to_lock_depths_;
this_initialized_ = src->this_initialized_;
}
std::string Dump(MethodVerifier* verifier) const REQUIRES_SHARED(Locks::mutator_lock_);
void FillWithGarbage() {
memset(&line_, 0xf1, num_regs_ * sizeof(uint16_t));
monitors_.clear();
reg_to_lock_depths_.clear();
}
/*
* We're creating a new instance of class C at address A. Any registers holding instances
* previously created at address A must be initialized by now. If not, we mark them as "conflict"
* to prevent them from being used (otherwise, MarkRefsAsInitialized would mark the old ones and
* the new ones at the same time).
*/
void MarkUninitRefsAsInvalid(MethodVerifier* verifier, const RegType& uninit_type)
REQUIRES_SHARED(Locks::mutator_lock_);
/*
* Update all registers holding "uninit_type" to instead hold the corresponding initialized
* reference type. This is called when an appropriate constructor is invoked -- all copies of
* the reference must be marked as initialized.
*/
void MarkRefsAsInitialized(MethodVerifier* verifier, const RegType& uninit_type)
REQUIRES_SHARED(Locks::mutator_lock_);
/*
* Update all registers to be Conflict except vsrc.
*/
void MarkAllRegistersAsConflicts(MethodVerifier* verifier);
void MarkAllRegistersAsConflictsExcept(MethodVerifier* verifier, uint32_t vsrc);
void MarkAllRegistersAsConflictsExceptWide(MethodVerifier* verifier, uint32_t vsrc);
void SetThisInitialized() {
this_initialized_ = true;
}
void CopyThisInitialized(const RegisterLine& src) {
this_initialized_ = src.this_initialized_;
}
/*
* Check constraints on constructor return. Specifically, make sure that the "this" argument got
* initialized.
* The "this" argument to <init> uses code offset kUninitThisArgAddr, which puts it at the start
* of the list in slot 0. If we see a register with an uninitialized slot 0 reference, we know it
* somehow didn't get initialized.
*/
bool CheckConstructorReturn(MethodVerifier* verifier) const;
// Compare two register lines. Returns 0 if they match.
// Using this for a sort is unwise, since the value can change based on machine endianness.
int CompareLine(const RegisterLine* line2) const {
if (monitors_ != line2->monitors_) {
return 1;
}
// TODO: DCHECK(reg_to_lock_depths_ == line2->reg_to_lock_depths_);
return memcmp(&line_, &line2->line_, num_regs_ * sizeof(uint16_t));
}
size_t NumRegs() const {
return num_regs_;
}
// Return how many bytes of memory a register line uses.
ALWAYS_INLINE static size_t ComputeSize(size_t num_regs);
/*
* Get the "this" pointer from a non-static method invocation. This returns the RegType so the
* caller can decide whether it needs the reference to be initialized or not. (Can also return
* kRegTypeZero if the reference can only be zero at this point.)
*
* The argument count is in vA, and the first argument is in vC, for both "simple" and "range"
* versions. We just need to make sure vA is >= 1 and then return vC.
* allow_failure will return Conflict() instead of causing a verification failure if there is an
* error.
*/
const RegType& GetInvocationThis(MethodVerifier* verifier,
const Instruction* inst,
bool allow_failure = false)
REQUIRES_SHARED(Locks::mutator_lock_);
/*
* Verify types for a simple two-register instruction (e.g. "neg-int").
* "dst_type" is stored into vA, and "src_type" is verified against vB.
*/
void CheckUnaryOp(MethodVerifier* verifier,
const Instruction* inst,
const RegType& dst_type,
const RegType& src_type)
REQUIRES_SHARED(Locks::mutator_lock_);
void CheckUnaryOpWide(MethodVerifier* verifier,
const Instruction* inst,
const RegType& dst_type1,
const RegType& dst_type2,
const RegType& src_type1,
const RegType& src_type2)
REQUIRES_SHARED(Locks::mutator_lock_);
void CheckUnaryOpToWide(MethodVerifier* verifier,
const Instruction* inst,
const RegType& dst_type1,
const RegType& dst_type2,
const RegType& src_type)
REQUIRES_SHARED(Locks::mutator_lock_);
void CheckUnaryOpFromWide(MethodVerifier* verifier,
const Instruction* inst,
const RegType& dst_type,
const RegType& src_type1,
const RegType& src_type2)
REQUIRES_SHARED(Locks::mutator_lock_);
/*
* Verify types for a simple three-register instruction (e.g. "add-int").
* "dst_type" is stored into vA, and "src_type1"/"src_type2" are verified
* against vB/vC.
*/
void CheckBinaryOp(MethodVerifier* verifier,
const Instruction* inst,
const RegType& dst_type,
const RegType& src_type1,
const RegType& src_type2,
bool check_boolean_op)
REQUIRES_SHARED(Locks::mutator_lock_);
void CheckBinaryOpWide(MethodVerifier* verifier,
const Instruction* inst,
const RegType& dst_type1,
const RegType& dst_type2,
const RegType& src_type1_1,
const RegType& src_type1_2,
const RegType& src_type2_1,
const RegType& src_type2_2)
REQUIRES_SHARED(Locks::mutator_lock_);
void CheckBinaryOpWideShift(MethodVerifier* verifier,
const Instruction* inst,
const RegType& long_lo_type,
const RegType& long_hi_type,
const RegType& int_type)
REQUIRES_SHARED(Locks::mutator_lock_);
/*
* Verify types for a binary "2addr" operation. "src_type1"/"src_type2"
* are verified against vA/vB, then "dst_type" is stored into vA.
*/
void CheckBinaryOp2addr(MethodVerifier* verifier,
const Instruction* inst,
const RegType& dst_type,
const RegType& src_type1,
const RegType& src_type2,
bool check_boolean_op)
REQUIRES_SHARED(Locks::mutator_lock_);
void CheckBinaryOp2addrWide(MethodVerifier* verifier,
const Instruction* inst,
const RegType& dst_type1,
const RegType& dst_type2,
const RegType& src_type1_1,
const RegType& src_type1_2,
const RegType& src_type2_1,
const RegType& src_type2_2)
REQUIRES_SHARED(Locks::mutator_lock_);
void CheckBinaryOp2addrWideShift(MethodVerifier* verifier,
const Instruction* inst,
const RegType& long_lo_type,
const RegType& long_hi_type,
const RegType& int_type)
REQUIRES_SHARED(Locks::mutator_lock_);
/*
* Verify types for A two-register instruction with a literal constant (e.g. "add-int/lit8").
* "dst_type" is stored into vA, and "src_type" is verified against vB.
*
* If "check_boolean_op" is set, we use the constant value in vC.
*/
void CheckLiteralOp(MethodVerifier* verifier,
const Instruction* inst,
const RegType& dst_type,
const RegType& src_type,
bool check_boolean_op,
bool is_lit16)
REQUIRES_SHARED(Locks::mutator_lock_);
// Verify/push monitor onto the monitor stack, locking the value in reg_idx at location insn_idx.
void PushMonitor(MethodVerifier* verifier, uint32_t reg_idx, int32_t insn_idx)
REQUIRES_SHARED(Locks::mutator_lock_);
// Verify/pop monitor from monitor stack ensuring that we believe the monitor is locked
void PopMonitor(MethodVerifier* verifier, uint32_t reg_idx)
REQUIRES_SHARED(Locks::mutator_lock_);
// Stack of currently held monitors and where they were locked
size_t MonitorStackDepth() const {
return monitors_.size();
}
// We expect no monitors to be held at certain points, such a method returns. Verify the stack
// is empty, queueing a LOCKING error else.
void VerifyMonitorStackEmpty(MethodVerifier* verifier) const;
bool MergeRegisters(MethodVerifier* verifier, const RegisterLine* incoming_line)
REQUIRES_SHARED(Locks::mutator_lock_);
size_t GetMonitorEnterCount() const {
return monitors_.size();
}
uint32_t GetMonitorEnterDexPc(size_t i) const {
return monitors_[i];
}
// We give access to the lock depth map to avoid an expensive poll loop for FindLocksAtDexPC.
template <typename T>
void IterateRegToLockDepths(T fn) const {
for (const auto& pair : reg_to_lock_depths_) {
const uint32_t reg = pair.first;
uint32_t depths = pair.second;
uint32_t depth = 0;
while (depths != 0) {
if ((depths & 1) != 0) {
fn(reg, depth);
}
depths >>= 1;
depth++;
}
}
}
private:
void CopyRegToLockDepth(size_t dst, size_t src) {
auto it = reg_to_lock_depths_.find(src);
if (it != reg_to_lock_depths_.end()) {
reg_to_lock_depths_.Put(dst, it->second);
}
}
bool IsSetLockDepth(size_t reg, size_t depth) {
auto it = reg_to_lock_depths_.find(reg);
if (it != reg_to_lock_depths_.end()) {
return (it->second & (1 << depth)) != 0;
} else {
return false;
}
}
bool SetRegToLockDepth(size_t reg, size_t depth) {
CHECK_LT(depth, 32u);
if (IsSetLockDepth(reg, depth)) {
return false; // Register already holds lock so locking twice is erroneous.
}
auto it = reg_to_lock_depths_.find(reg);
if (it == reg_to_lock_depths_.end()) {
reg_to_lock_depths_.Put(reg, 1 << depth);
} else {
it->second |= (1 << depth);
}
return true;
}
void ClearRegToLockDepth(size_t reg, size_t depth);
void ClearAllRegToLockDepths(size_t reg) {
reg_to_lock_depths_.erase(reg);
}
RegisterLine(size_t num_regs, MethodVerifier* verifier);
// Storage for the result register's type, valid after an invocation.
uint16_t result_[2];
// Length of reg_types_
const uint32_t num_regs_;
// A stack of monitor enter locations.
ScopedArenaVector<uint32_t> monitors_;
// A map from register to a bit vector of indices into the monitors_ stack. As we pop the monitor
// stack we verify that monitor-enter/exit are correctly nested. That is, if there was a
// monitor-enter on v5 and then on v6, we expect the monitor-exit to be on v6 then on v5.
RegToLockDepthsMap reg_to_lock_depths_;
// Whether "this" initialization (a constructor supercall) has happened.
bool this_initialized_;
// An array of RegType Ids associated with each dex register.
uint16_t line_[1];
DISALLOW_COPY_AND_ASSIGN(RegisterLine);
};
class RegisterLineArenaDelete : public ArenaDelete<RegisterLine> {
public:
void operator()(RegisterLine* ptr) const;
};
} // namespace verifier
} // namespace art
#endif // ART_RUNTIME_VERIFIER_REGISTER_LINE_H_