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cobalt / cobalt / 50d4ee4d2d42567d196777b2b6c88fcb51217f8b / . / src / v8 / src / wasm / function-body-decoder-impl.h
blob: 04d918b0a4fe0991b67ee9d5dde4d695a742afbc [file] [log] [blame]
// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_WASM_FUNCTION_BODY_DECODER_IMPL_H_
#define V8_WASM_FUNCTION_BODY_DECODER_IMPL_H_
// Do only include this header for implementing new Interface of the
// WasmFullDecoder.
#include "src/bit-vector.h"
#include "src/wasm/decoder.h"
#include "src/wasm/function-body-decoder.h"
#include "src/wasm/wasm-limits.h"
#include "src/wasm/wasm-module.h"
#include "src/wasm/wasm-opcodes.h"
namespace v8 {
namespace internal {
namespace wasm {
struct WasmGlobal;
struct WasmException;
#define TRACE(...) \
do { \
if (FLAG_trace_wasm_decoder) PrintF(__VA_ARGS__); \
} while (false)
#define TRACE_INST_FORMAT " @%-8d #%-20s|"
// Return the evaluation of `condition` if validate==true, DCHECK that it's
// true and always return true otherwise.
#define VALIDATE(condition) \
(validate ? (condition) : [&] { \
DCHECK(condition); \
return true; \
}())
#define CHECK_PROTOTYPE_OPCODE(flag) \
DCHECK(!this->module_ || !this->module_->is_asm_js()); \
if (!FLAG_experimental_wasm_##flag) { \
this->error("Invalid opcode (enable with --experimental-wasm-" #flag ")"); \
break; \
}
#define OPCODE_ERROR(opcode, message) \
(this->errorf(this->pc_, "%s: %s", WasmOpcodes::OpcodeName(opcode), \
(message)))
#define ATOMIC_OP_LIST(V) \
V(I32AtomicLoad, Uint32) \
V(I32AtomicAdd, Uint32) \
V(I32AtomicSub, Uint32) \
V(I32AtomicAnd, Uint32) \
V(I32AtomicOr, Uint32) \
V(I32AtomicXor, Uint32) \
V(I32AtomicExchange, Uint32) \
V(I32AtomicLoad8U, Uint8) \
V(I32AtomicAdd8U, Uint8) \
V(I32AtomicSub8U, Uint8) \
V(I32AtomicAnd8U, Uint8) \
V(I32AtomicOr8U, Uint8) \
V(I32AtomicXor8U, Uint8) \
V(I32AtomicExchange8U, Uint8) \
V(I32AtomicLoad16U, Uint16) \
V(I32AtomicAdd16U, Uint16) \
V(I32AtomicSub16U, Uint16) \
V(I32AtomicAnd16U, Uint16) \
V(I32AtomicOr16U, Uint16) \
V(I32AtomicXor16U, Uint16) \
V(I32AtomicExchange16U, Uint16) \
V(I32AtomicCompareExchange, Uint32) \
V(I32AtomicCompareExchange8U, Uint8) \
V(I32AtomicCompareExchange16U, Uint16)
#define ATOMIC_STORE_OP_LIST(V) \
V(I32AtomicStore, Uint32) \
V(I32AtomicStore8U, Uint8) \
V(I32AtomicStore16U, Uint16)
template <typename T, typename Allocator>
Vector<T> vec2vec(std::vector<T, Allocator>& vec) {
return Vector<T>(vec.data(), vec.size());
}
// Helpers for decoding different kinds of operands which follow bytecodes.
template <Decoder::ValidateFlag validate>
struct LocalIndexOperand {
uint32_t index;
ValueType type = kWasmStmt;
unsigned length;
inline LocalIndexOperand(Decoder* decoder, const byte* pc) {
index = decoder->read_u32v<validate>(pc + 1, &length, "local index");
}
};
template <Decoder::ValidateFlag validate>
struct ExceptionIndexOperand {
uint32_t index;
const WasmException* exception = nullptr;
unsigned length;
inline ExceptionIndexOperand(Decoder* decoder, const byte* pc) {
index = decoder->read_u32v<validate>(pc + 1, &length, "exception index");
}
};
template <Decoder::ValidateFlag validate>
struct ImmI32Operand {
int32_t value;
unsigned length;
inline ImmI32Operand(Decoder* decoder, const byte* pc) {
value = decoder->read_i32v<validate>(pc + 1, &length, "immi32");
}
};
template <Decoder::ValidateFlag validate>
struct ImmI64Operand {
int64_t value;
unsigned length;
inline ImmI64Operand(Decoder* decoder, const byte* pc) {
value = decoder->read_i64v<validate>(pc + 1, &length, "immi64");
}
};
template <Decoder::ValidateFlag validate>
struct ImmF32Operand {
float value;
unsigned length = 4;
inline ImmF32Operand(Decoder* decoder, const byte* pc) {
// Avoid bit_cast because it might not preserve the signalling bit of a NaN.
uint32_t tmp = decoder->read_u32<validate>(pc + 1, "immf32");
memcpy(&value, &tmp, sizeof(value));
}
};
template <Decoder::ValidateFlag validate>
struct ImmF64Operand {
double value;
unsigned length = 8;
inline ImmF64Operand(Decoder* decoder, const byte* pc) {
// Avoid bit_cast because it might not preserve the signalling bit of a NaN.
uint64_t tmp = decoder->read_u64<validate>(pc + 1, "immf64");
memcpy(&value, &tmp, sizeof(value));
}
};
template <Decoder::ValidateFlag validate>
struct GlobalIndexOperand {
uint32_t index;
ValueType type = kWasmStmt;
const WasmGlobal* global = nullptr;
unsigned length;
inline GlobalIndexOperand(Decoder* decoder, const byte* pc) {
index = decoder->read_u32v<validate>(pc + 1, &length, "global index");
}
};
template <Decoder::ValidateFlag validate>
struct BlockTypeOperand {
unsigned length = 1;
ValueType type = kWasmStmt;
uint32_t sig_index = 0;
FunctionSig* sig = nullptr;
inline BlockTypeOperand(Decoder* decoder, const byte* pc) {
uint8_t val = decoder->read_u8<validate>(pc + 1, "block type");
if (!decode_local_type(val, &type)) {
// Handle multi-value blocks.
if (!VALIDATE(FLAG_experimental_wasm_mv)) {
decoder->error(pc + 1, "invalid block type");
return;
}
int32_t index =
decoder->read_i32v<validate>(pc + 1, &length, "block arity");
if (!VALIDATE(length > 0 && index >= 0)) {
decoder->error(pc + 1, "invalid block type index");
return;
}
sig_index = static_cast<uint32_t>(index);
}
}
// Decode a byte representing a local type. Return {false} if the encoded
// byte was invalid or the start of a type index.
inline bool decode_local_type(uint8_t val, ValueType* result) {
switch (static_cast<ValueTypeCode>(val)) {
case kLocalVoid:
*result = kWasmStmt;
return true;
case kLocalI32:
*result = kWasmI32;
return true;
case kLocalI64:
*result = kWasmI64;
return true;
case kLocalF32:
*result = kWasmF32;
return true;
case kLocalF64:
*result = kWasmF64;
return true;
case kLocalS128:
*result = kWasmS128;
return true;
default:
*result = kWasmVar;
return false;
}
}
uint32_t in_arity() const {
if (type != kWasmVar) return 0;
return static_cast<uint32_t>(sig->parameter_count());
}
uint32_t out_arity() const {
if (type == kWasmStmt) return 0;
if (type != kWasmVar) return 1;
return static_cast<uint32_t>(sig->return_count());
}
ValueType in_type(uint32_t index) {
DCHECK_EQ(kWasmVar, type);
return sig->GetParam(index);
}
ValueType out_type(uint32_t index) {
if (type == kWasmVar) return sig->GetReturn(index);
DCHECK_NE(kWasmStmt, type);
DCHECK_EQ(0, index);
return type;
}
};
template <Decoder::ValidateFlag validate>
struct BreakDepthOperand {
uint32_t depth;
unsigned length;
inline BreakDepthOperand(Decoder* decoder, const byte* pc) {
depth = decoder->read_u32v<validate>(pc + 1, &length, "break depth");
}
};
template <Decoder::ValidateFlag validate>
struct CallIndirectOperand {
uint32_t table_index;
uint32_t index;
FunctionSig* sig = nullptr;
unsigned length = 0;
inline CallIndirectOperand(Decoder* decoder, const byte* pc) {
unsigned len = 0;
index = decoder->read_u32v<validate>(pc + 1, &len, "signature index");
if (!VALIDATE(decoder->ok())) return;
table_index = decoder->read_u8<validate>(pc + 1 + len, "table index");
if (!VALIDATE(table_index == 0)) {
decoder->errorf(pc + 1 + len, "expected table index 0, found %u",
table_index);
}
length = 1 + len;
}
};
template <Decoder::ValidateFlag validate>
struct CallFunctionOperand {
uint32_t index;
FunctionSig* sig = nullptr;
unsigned length;
inline CallFunctionOperand(Decoder* decoder, const byte* pc) {
index = decoder->read_u32v<validate>(pc + 1, &length, "function index");
}
};
template <Decoder::ValidateFlag validate>
struct MemoryIndexOperand {
uint32_t index;
unsigned length = 1;
inline MemoryIndexOperand(Decoder* decoder, const byte* pc) {
index = decoder->read_u8<validate>(pc + 1, "memory index");
if (!VALIDATE(index == 0)) {
decoder->errorf(pc + 1, "expected memory index 0, found %u", index);
}
}
};
template <Decoder::ValidateFlag validate>
struct BranchTableOperand {
uint32_t table_count;
const byte* start;
const byte* table;
inline BranchTableOperand(Decoder* decoder, const byte* pc) {
DCHECK_EQ(kExprBrTable, decoder->read_u8<validate>(pc, "opcode"));
start = pc + 1;
unsigned len = 0;
table_count = decoder->read_u32v<validate>(pc + 1, &len, "table count");
table = pc + 1 + len;
}
};
// A helper to iterate over a branch table.
template <Decoder::ValidateFlag validate>
class BranchTableIterator {
public:
unsigned cur_index() { return index_; }
bool has_next() { return decoder_->ok() && index_ <= table_count_; }
uint32_t next() {
DCHECK(has_next());
index_++;
unsigned length;
uint32_t result =
decoder_->read_u32v<validate>(pc_, &length, "branch table entry");
pc_ += length;
return result;
}
// length, including the length of the {BranchTableOperand}, but not the
// opcode.
unsigned length() {
while (has_next()) next();
return static_cast<unsigned>(pc_ - start_);
}
const byte* pc() { return pc_; }
BranchTableIterator(Decoder* decoder,
const BranchTableOperand<validate>& operand)
: decoder_(decoder),
start_(operand.start),
pc_(operand.table),
index_(0),
table_count_(operand.table_count) {}
private:
Decoder* decoder_;
const byte* start_;
const byte* pc_;
uint32_t index_; // the current index.
uint32_t table_count_; // the count of entries, not including default.
};
template <Decoder::ValidateFlag validate>
struct MemoryAccessOperand {
uint32_t alignment;
uint32_t offset;
unsigned length = 0;
inline MemoryAccessOperand(Decoder* decoder, const byte* pc,
uint32_t max_alignment) {
unsigned alignment_length;
alignment =
decoder->read_u32v<validate>(pc + 1, &alignment_length, "alignment");
if (!VALIDATE(alignment <= max_alignment)) {
decoder->errorf(pc + 1,
"invalid alignment; expected maximum alignment is %u, "
"actual alignment is %u",
max_alignment, alignment);
}
if (!VALIDATE(decoder->ok())) return;
unsigned offset_length;
offset = decoder->read_u32v<validate>(pc + 1 + alignment_length,
&offset_length, "offset");
length = alignment_length + offset_length;
}
};
// Operand for SIMD lane operations.
template <Decoder::ValidateFlag validate>
struct SimdLaneOperand {
uint8_t lane;
unsigned length = 1;
inline SimdLaneOperand(Decoder* decoder, const byte* pc) {
lane = decoder->read_u8<validate>(pc + 2, "lane");
}
};
// Operand for SIMD shift operations.
template <Decoder::ValidateFlag validate>
struct SimdShiftOperand {
uint8_t shift;
unsigned length = 1;
inline SimdShiftOperand(Decoder* decoder, const byte* pc) {
shift = decoder->read_u8<validate>(pc + 2, "shift");
}
};
// Operand for SIMD S8x16 shuffle operations.
template <Decoder::ValidateFlag validate>
struct Simd8x16ShuffleOperand {
uint8_t shuffle[kSimd128Size] = {0};
inline Simd8x16ShuffleOperand(Decoder* decoder, const byte* pc) {
for (uint32_t i = 0; i < kSimd128Size; ++i) {
shuffle[i] = decoder->read_u8<validate>(pc + 2 + i, "shuffle");
if (!VALIDATE(decoder->ok())) return;
}
}
};
// An entry on the value stack.
struct ValueBase {
const byte* pc;
ValueType type;
// Named constructors.
static ValueBase Unreachable(const byte* pc) { return {pc, kWasmVar}; }
static ValueBase New(const byte* pc, ValueType type) { return {pc, type}; }
};
template <typename Value>
struct Merge {
uint32_t arity;
union {
Value* array;
Value first;
} vals; // Either multiple values or a single value.
// Tracks whether this merge was ever reached. Uses precise reachability, like
// Reachability::kReachable.
bool reached;
Merge(bool reached = false) : reached(reached) {}
Value& operator[](uint32_t i) {
DCHECK_GT(arity, i);
return arity == 1 ? vals.first : vals.array[i];
}
};
enum ControlKind : uint8_t {
kControlIf,
kControlIfElse,
kControlBlock,
kControlLoop,
kControlTry,
kControlTryCatch
};
enum Reachability : uint8_t {
// reachable code.
kReachable,
// reachable code in unreachable block (implies normal validation).
kSpecOnlyReachable,
// code unreachable in its own block (implies polymorphic validation).
kUnreachable
};
// An entry on the control stack (i.e. if, block, loop, or try).
template <typename Value>
struct ControlBase {
ControlKind kind;
uint32_t stack_depth; // stack height at the beginning of the construct.
const byte* pc;
Reachability reachability = kReachable;
// Values merged into the start or end of this control construct.
Merge<Value> start_merge;
Merge<Value> end_merge;
ControlBase() = default;
ControlBase(ControlKind kind, uint32_t stack_depth, const byte* pc)
: kind(kind), stack_depth(stack_depth), pc(pc) {}
// Check whether the current block is reachable.
bool reachable() const { return reachability == kReachable; }
// Check whether the rest of the block is unreachable.
// Note that this is different from {!reachable()}, as there is also the
// "indirect unreachable state", for which both {reachable()} and
// {unreachable()} return false.
bool unreachable() const { return reachability == kUnreachable; }
// Return the reachability of new control structs started in this block.
Reachability innerReachability() const {
return reachability == kReachable ? kReachable : kSpecOnlyReachable;
}
bool is_if() const { return is_onearmed_if() || is_if_else(); }
bool is_onearmed_if() const { return kind == kControlIf; }
bool is_if_else() const { return kind == kControlIfElse; }
bool is_block() const { return kind == kControlBlock; }
bool is_loop() const { return kind == kControlLoop; }
bool is_try() const { return is_incomplete_try() || is_try_catch(); }
bool is_incomplete_try() const { return kind == kControlTry; }
bool is_try_catch() const { return kind == kControlTryCatch; }
inline Merge<Value>* br_merge() {
return is_loop() ? &this->start_merge : &this->end_merge;
}
// Named constructors.
static ControlBase Block(const byte* pc, uint32_t stack_depth) {
return {kControlBlock, stack_depth, pc};
}
static ControlBase If(const byte* pc, uint32_t stack_depth) {
return {kControlIf, stack_depth, pc};
}
static ControlBase Loop(const byte* pc, uint32_t stack_depth) {
return {kControlLoop, stack_depth, pc};
}
static ControlBase Try(const byte* pc, uint32_t stack_depth) {
return {kControlTry, stack_depth, pc};
}
};
#define CONCRETE_NAMED_CONSTRUCTOR(concrete_type, abstract_type, name) \
template <typename... Args> \
static concrete_type name(Args&&... args) { \
concrete_type val; \
static_cast<abstract_type&>(val) = \
abstract_type::name(std::forward<Args>(args)...); \
return val; \
}
// Provide the default named constructors, which default-initialize the
// ConcreteType and the initialize the fields of ValueBase correctly.
// Use like this:
// struct Value : public ValueWithNamedConstructors<Value> { int new_field; };
template <typename ConcreteType>
struct ValueWithNamedConstructors : public ValueBase {
// Named constructors.
CONCRETE_NAMED_CONSTRUCTOR(ConcreteType, ValueBase, Unreachable)
CONCRETE_NAMED_CONSTRUCTOR(ConcreteType, ValueBase, New)
};
// Provide the default named constructors, which default-initialize the
// ConcreteType and the initialize the fields of ControlBase correctly.
// Use like this:
// struct Control : public ControlWithNamedConstructors<Control, Value> {
// int my_uninitialized_field;
// char* other_field = nullptr;
// };
template <typename ConcreteType, typename Value>
struct ControlWithNamedConstructors : public ControlBase<Value> {
// Named constructors.
CONCRETE_NAMED_CONSTRUCTOR(ConcreteType, ControlBase<Value>, Block)
CONCRETE_NAMED_CONSTRUCTOR(ConcreteType, ControlBase<Value>, If)
CONCRETE_NAMED_CONSTRUCTOR(ConcreteType, ControlBase<Value>, Loop)
CONCRETE_NAMED_CONSTRUCTOR(ConcreteType, ControlBase<Value>, Try)
};
// This is the list of callback functions that an interface for the
// WasmFullDecoder should implement.
// F(Name, args...)
#define INTERFACE_FUNCTIONS(F) \
/* General: */ \
F(StartFunction) \
F(StartFunctionBody, Control* block) \
F(FinishFunction) \
F(OnFirstError) \
F(NextInstruction, WasmOpcode) \
/* Control: */ \
F(Block, Control* block) \
F(Loop, Control* block) \
F(Try, Control* block) \
F(If, const Value& cond, Control* if_block) \
F(FallThruTo, Control* c) \
F(PopControl, Control* block) \
F(EndControl, Control* block) \
/* Instructions: */ \
F(UnOp, WasmOpcode opcode, FunctionSig*, const Value& value, Value* result) \
F(BinOp, WasmOpcode opcode, FunctionSig*, const Value& lhs, \
const Value& rhs, Value* result) \
F(I32Const, Value* result, int32_t value) \
F(I64Const, Value* result, int64_t value) \
F(F32Const, Value* result, float value) \
F(F64Const, Value* result, double value) \
F(Drop, const Value& value) \
F(DoReturn, Vector<Value> values, bool implicit) \
F(GetLocal, Value* result, const LocalIndexOperand<validate>& operand) \
F(SetLocal, const Value& value, const LocalIndexOperand<validate>& operand) \
F(TeeLocal, const Value& value, Value* result, \
const LocalIndexOperand<validate>& operand) \
F(GetGlobal, Value* result, const GlobalIndexOperand<validate>& operand) \
F(SetGlobal, const Value& value, \
const GlobalIndexOperand<validate>& operand) \
F(Unreachable) \
F(Select, const Value& cond, const Value& fval, const Value& tval, \
Value* result) \
F(Br, Control* target) \
F(BrIf, const Value& cond, Control* target) \
F(BrTable, const BranchTableOperand<validate>& operand, const Value& key) \
F(Else, Control* if_block) \
F(LoadMem, LoadType type, const MemoryAccessOperand<validate>& operand, \
const Value& index, Value* result) \
F(StoreMem, StoreType type, const MemoryAccessOperand<validate>& operand, \
const Value& index, const Value& value) \
F(CurrentMemoryPages, Value* result) \
F(GrowMemory, const Value& value, Value* result) \
F(CallDirect, const CallFunctionOperand<validate>& operand, \
const Value args[], Value returns[]) \
F(CallIndirect, const Value& index, \
const CallIndirectOperand<validate>& operand, const Value args[], \
Value returns[]) \
F(SimdOp, WasmOpcode opcode, Vector<Value> args, Value* result) \
F(SimdLaneOp, WasmOpcode opcode, const SimdLaneOperand<validate>& operand, \
const Vector<Value> inputs, Value* result) \
F(SimdShiftOp, WasmOpcode opcode, const SimdShiftOperand<validate>& operand, \
const Value& input, Value* result) \
F(Simd8x16ShuffleOp, const Simd8x16ShuffleOperand<validate>& operand, \
const Value& input0, const Value& input1, Value* result) \
F(Throw, const ExceptionIndexOperand<validate>&, Control* block, \
const Vector<Value>& args) \
F(CatchException, const ExceptionIndexOperand<validate>& operand, \
Control* block, Vector<Value> caught_values) \
F(AtomicOp, WasmOpcode opcode, Vector<Value> args, \
const MemoryAccessOperand<validate>& operand, Value* result)
// Generic Wasm bytecode decoder with utilities for decoding operands,
// lengths, etc.
template <Decoder::ValidateFlag validate>
class WasmDecoder : public Decoder {
public:
WasmDecoder(const WasmModule* module, FunctionSig* sig, const byte* start,
const byte* end, uint32_t buffer_offset = 0)
: Decoder(start, end, buffer_offset),
module_(module),
sig_(sig),
local_types_(nullptr) {}
const WasmModule* module_;
FunctionSig* sig_;
ZoneVector<ValueType>* local_types_;
uint32_t total_locals() const {
return local_types_ == nullptr
? 0
: static_cast<uint32_t>(local_types_->size());
}
static bool DecodeLocals(Decoder* decoder, const FunctionSig* sig,
ZoneVector<ValueType>* type_list) {
DCHECK_NOT_NULL(type_list);
DCHECK_EQ(0, type_list->size());
// Initialize from signature.
if (sig != nullptr) {
type_list->assign(sig->parameters().begin(), sig->parameters().end());
}
// Decode local declarations, if any.
uint32_t entries = decoder->consume_u32v("local decls count");
if (decoder->failed()) return false;
TRACE("local decls count: %u\n", entries);
while (entries-- > 0 && decoder->ok() && decoder->more()) {
uint32_t count = decoder->consume_u32v("local count");
if (decoder->failed()) return false;
if ((count + type_list->size()) > kV8MaxWasmFunctionLocals) {
decoder->error(decoder->pc() - 1, "local count too large");
return false;
}
byte code = decoder->consume_u8("local type");
if (decoder->failed()) return false;
ValueType type;
switch (code) {
case kLocalI32:
type = kWasmI32;
break;
case kLocalI64:
type = kWasmI64;
break;
case kLocalF32:
type = kWasmF32;
break;
case kLocalF64:
type = kWasmF64;
break;
case kLocalS128:
if (FLAG_experimental_wasm_simd) {
type = kWasmS128;
break;
}
// else fall through to default.
default:
decoder->error(decoder->pc() - 1, "invalid local type");
return false;
}
type_list->insert(type_list->end(), count, type);
}
DCHECK(decoder->ok());
return true;
}
static BitVector* AnalyzeLoopAssignment(Decoder* decoder, const byte* pc,
uint32_t locals_count, Zone* zone) {
if (pc >= decoder->end()) return nullptr;
if (*pc != kExprLoop) return nullptr;
// The number of locals_count is augmented by 2 so that 'locals_count - 2'
// can be used to track mem_size, and 'locals_count - 1' to track mem_start.
BitVector* assigned = new (zone) BitVector(locals_count, zone);
int depth = 0;
// Iteratively process all AST nodes nested inside the loop.
while (pc < decoder->end() && decoder->ok()) {
WasmOpcode opcode = static_cast<WasmOpcode>(*pc);
unsigned length = 1;
switch (opcode) {
case kExprLoop:
case kExprIf:
case kExprBlock:
case kExprTry:
length = OpcodeLength(decoder, pc);
depth++;
break;
case kExprSetLocal: // fallthru
case kExprTeeLocal: {
LocalIndexOperand<Decoder::kValidate> operand(decoder, pc);
if (assigned->length() > 0 &&
operand.index < static_cast<uint32_t>(assigned->length())) {
// Unverified code might have an out-of-bounds index.
assigned->Add(operand.index);
}
length = 1 + operand.length;
break;
}
case kExprGrowMemory:
case kExprCallFunction:
case kExprCallIndirect:
// Add context cache nodes to the assigned set.
// TODO(titzer): make this more clear.
assigned->Add(locals_count - 1);
length = OpcodeLength(decoder, pc);
break;
case kExprEnd:
depth--;
break;
default:
length = OpcodeLength(decoder, pc);
break;
}
if (depth <= 0) break;
pc += length;
}
return decoder->ok() ? assigned : nullptr;
}
inline bool Validate(const byte* pc,
LocalIndexOperand<Decoder::kValidate>& operand) {
if (!VALIDATE(operand.index < total_locals())) {
errorf(pc + 1, "invalid local index: %u", operand.index);
return false;
}
operand.type = local_types_ ? local_types_->at(operand.index) : kWasmStmt;
return true;
}
inline bool Validate(const byte* pc,
ExceptionIndexOperand<validate>& operand) {
if (!VALIDATE(module_ != nullptr &&
operand.index < module_->exceptions.size())) {
errorf(pc + 1, "Invalid exception index: %u", operand.index);
return false;
}
operand.exception = &module_->exceptions[operand.index];
return true;
}
inline bool Validate(const byte* pc, GlobalIndexOperand<validate>& operand) {
if (!VALIDATE(module_ != nullptr &&
operand.index < module_->globals.size())) {
errorf(pc + 1, "invalid global index: %u", operand.index);
return false;
}
operand.global = &module_->globals[operand.index];
operand.type = operand.global->type;
return true;
}
inline bool Complete(const byte* pc, CallFunctionOperand<validate>& operand) {
if (!VALIDATE(module_ != nullptr &&
operand.index < module_->functions.size())) {
return false;
}
operand.sig = module_->functions[operand.index].sig;
return true;
}
inline bool Validate(const byte* pc, CallFunctionOperand<validate>& operand) {
if (Complete(pc, operand)) {
return true;
}
errorf(pc + 1, "invalid function index: %u", operand.index);
return false;
}
inline bool Complete(const byte* pc, CallIndirectOperand<validate>& operand) {
if (!VALIDATE(module_ != nullptr &&
operand.index < module_->signatures.size())) {
return false;
}
operand.sig = module_->signatures[operand.index];
return true;
}
inline bool Validate(const byte* pc, CallIndirectOperand<validate>& operand) {
if (!VALIDATE(module_ != nullptr && !module_->function_tables.empty())) {
error("function table has to exist to execute call_indirect");
return false;
}
if (!Complete(pc, operand)) {
errorf(pc + 1, "invalid signature index: #%u", operand.index);
return false;
}
return true;
}
inline bool Validate(const byte* pc, BreakDepthOperand<validate>& operand,
size_t control_depth) {
if (!VALIDATE(operand.depth < control_depth)) {
errorf(pc + 1, "invalid break depth: %u", operand.depth);
return false;
}
return true;
}
bool Validate(const byte* pc, BranchTableOperand<validate>& operand,
size_t block_depth) {
if (!VALIDATE(operand.table_count < kV8MaxWasmFunctionSize)) {
errorf(pc + 1, "invalid table count (> max function size): %u",
operand.table_count);
return false;
}
return checkAvailable(operand.table_count);
}
inline bool Validate(const byte* pc, WasmOpcode opcode,
SimdLaneOperand<validate>& operand) {
uint8_t num_lanes = 0;
switch (opcode) {
case kExprF32x4ExtractLane:
case kExprF32x4ReplaceLane:
case kExprI32x4ExtractLane:
case kExprI32x4ReplaceLane:
num_lanes = 4;
break;
case kExprI16x8ExtractLane:
case kExprI16x8ReplaceLane:
num_lanes = 8;
break;
case kExprI8x16ExtractLane:
case kExprI8x16ReplaceLane:
num_lanes = 16;
break;
default:
UNREACHABLE();
break;
}
if (!VALIDATE(operand.lane >= 0 && operand.lane < num_lanes)) {
error(pc_ + 2, "invalid lane index");
return false;
} else {
return true;
}
}
inline bool Validate(const byte* pc, WasmOpcode opcode,
SimdShiftOperand<validate>& operand) {
uint8_t max_shift = 0;
switch (opcode) {
case kExprI32x4Shl:
case kExprI32x4ShrS:
case kExprI32x4ShrU:
max_shift = 32;
break;
case kExprI16x8Shl:
case kExprI16x8ShrS:
case kExprI16x8ShrU:
max_shift = 16;
break;
case kExprI8x16Shl:
case kExprI8x16ShrS:
case kExprI8x16ShrU:
max_shift = 8;
break;
default:
UNREACHABLE();
break;
}
if (!VALIDATE(operand.shift >= 0 && operand.shift < max_shift)) {
error(pc_ + 2, "invalid shift amount");
return false;
} else {
return true;
}
}
inline bool Validate(const byte* pc,
Simd8x16ShuffleOperand<validate>& operand) {
uint8_t max_lane = 0;
for (uint32_t i = 0; i < kSimd128Size; ++i)
max_lane = std::max(max_lane, operand.shuffle[i]);
// Shuffle indices must be in [0..31] for a 16 lane shuffle.
if (!VALIDATE(max_lane <= 2 * kSimd128Size)) {
error(pc_ + 2, "invalid shuffle mask");
return false;
}
return true;
}
static unsigned OpcodeLength(Decoder* decoder, const byte* pc) {
WasmOpcode opcode = static_cast<WasmOpcode>(*pc);
switch (opcode) {
#define DECLARE_OPCODE_CASE(name, opcode, sig) case kExpr##name:
FOREACH_LOAD_MEM_OPCODE(DECLARE_OPCODE_CASE)
FOREACH_STORE_MEM_OPCODE(DECLARE_OPCODE_CASE)
#undef DECLARE_OPCODE_CASE
{
MemoryAccessOperand<validate> operand(decoder, pc, UINT32_MAX);
return 1 + operand.length;
}
case kExprBr:
case kExprBrIf: {
BreakDepthOperand<validate> operand(decoder, pc);
return 1 + operand.length;
}
case kExprSetGlobal:
case kExprGetGlobal: {
GlobalIndexOperand<validate> operand(decoder, pc);
return 1 + operand.length;
}
case kExprCallFunction: {
CallFunctionOperand<validate> operand(decoder, pc);
return 1 + operand.length;
}
case kExprCallIndirect: {
CallIndirectOperand<validate> operand(decoder, pc);
return 1 + operand.length;
}
case kExprTry:
case kExprIf: // fall through
case kExprLoop:
case kExprBlock: {
BlockTypeOperand<validate> operand(decoder, pc);
return 1 + operand.length;
}
case kExprThrow:
case kExprCatch: {
ExceptionIndexOperand<validate> operand(decoder, pc);
return 1 + operand.length;
}
case kExprSetLocal:
case kExprTeeLocal:
case kExprGetLocal: {
LocalIndexOperand<Decoder::kValidate> operand(decoder, pc);
return 1 + operand.length;
}
case kExprBrTable: {
BranchTableOperand<validate> operand(decoder, pc);
BranchTableIterator<validate> iterator(decoder, operand);
return 1 + iterator.length();
}
case kExprI32Const: {
ImmI32Operand<validate> operand(decoder, pc);
return 1 + operand.length;
}
case kExprI64Const: {
ImmI64Operand<validate> operand(decoder, pc);
return 1 + operand.length;
}
case kExprGrowMemory:
case kExprMemorySize: {
MemoryIndexOperand<validate> operand(decoder, pc);
return 1 + operand.length;
}
case kExprF32Const:
return 5;
case kExprF64Const:
return 9;
case kNumericPrefix:
return 2;
case kSimdPrefix: {
byte simd_index = decoder->read_u8<validate>(pc + 1, "simd_index");
WasmOpcode opcode =
static_cast<WasmOpcode>(kSimdPrefix << 8 | simd_index);
switch (opcode) {
#define DECLARE_OPCODE_CASE(name, opcode, sig) case kExpr##name:
FOREACH_SIMD_0_OPERAND_OPCODE(DECLARE_OPCODE_CASE)
#undef DECLARE_OPCODE_CASE
return 2;
#define DECLARE_OPCODE_CASE(name, opcode, sig) case kExpr##name:
FOREACH_SIMD_1_OPERAND_OPCODE(DECLARE_OPCODE_CASE)
#undef DECLARE_OPCODE_CASE
return 3;
#define DECLARE_OPCODE_CASE(name, opcode, sig) case kExpr##name:
FOREACH_SIMD_MEM_OPCODE(DECLARE_OPCODE_CASE)
#undef DECLARE_OPCODE_CASE
{
MemoryAccessOperand<validate> operand(decoder, pc + 1, UINT32_MAX);
return 2 + operand.length;
}
// Shuffles require a byte per lane, or 16 immediate bytes.
case kExprS8x16Shuffle:
return 2 + kSimd128Size;
default:
decoder->error(pc, "invalid SIMD opcode");
return 2;
}
}
case kAtomicPrefix: {
byte atomic_index = decoder->read_u8<validate>(pc + 1, "atomic_index");
WasmOpcode opcode =
static_cast<WasmOpcode>(kAtomicPrefix << 8 | atomic_index);
switch (opcode) {
#define DECLARE_OPCODE_CASE(name, opcode, sig) case kExpr##name:
FOREACH_ATOMIC_OPCODE(DECLARE_OPCODE_CASE)
#undef DECLARE_OPCODE_CASE
{
MemoryAccessOperand<validate> operand(decoder, pc + 1, UINT32_MAX);
return 2 + operand.length;
}
default:
decoder->error(pc, "invalid Atomics opcode");
return 2;
}
}
default:
return 1;
}
}
std::pair<uint32_t, uint32_t> StackEffect(const byte* pc) {
WasmOpcode opcode = static_cast<WasmOpcode>(*pc);
// Handle "simple" opcodes with a fixed signature first.
FunctionSig* sig = WasmOpcodes::Signature(opcode);
if (!sig) sig = WasmOpcodes::AsmjsSignature(opcode);
if (sig) return {sig->parameter_count(), sig->return_count()};
#define DECLARE_OPCODE_CASE(name, opcode, sig) case kExpr##name:
// clang-format off
switch (opcode) {
case kExprSelect:
return {3, 1};
FOREACH_STORE_MEM_OPCODE(DECLARE_OPCODE_CASE)
return {2, 0};
FOREACH_LOAD_MEM_OPCODE(DECLARE_OPCODE_CASE)
case kExprTeeLocal:
case kExprGrowMemory:
return {1, 1};
case kExprSetLocal:
case kExprSetGlobal:
case kExprDrop:
case kExprBrIf:
case kExprBrTable:
case kExprIf:
return {1, 0};
case kExprGetLocal:
case kExprGetGlobal:
case kExprI32Const:
case kExprI64Const:
case kExprF32Const:
case kExprF64Const:
case kExprMemorySize:
return {0, 1};
case kExprCallFunction: {
CallFunctionOperand<validate> operand(this, pc);
CHECK(Complete(pc, operand));
return {operand.sig->parameter_count(), operand.sig->return_count()};
}
case kExprCallIndirect: {
CallIndirectOperand<validate> operand(this, pc);
CHECK(Complete(pc, operand));
// Indirect calls pop an additional argument for the table index.
return {operand.sig->parameter_count() + 1,
operand.sig->return_count()};
}
case kExprBr:
case kExprBlock:
case kExprLoop:
case kExprEnd:
case kExprElse:
case kExprNop:
case kExprReturn:
case kExprUnreachable:
return {0, 0};
case kNumericPrefix:
case kAtomicPrefix:
case kSimdPrefix: {
opcode = static_cast<WasmOpcode>(opcode << 8 | *(pc + 1));
switch (opcode) {
case kExprI32AtomicStore:
case kExprI32AtomicStore8U:
case kExprI32AtomicStore16U:
case kExprS128StoreMem:
return {2, 0};
default: {
sig = WasmOpcodes::Signature(opcode);
if (sig) {
return {sig->parameter_count(), sig->return_count()};
}
}
}
}
default:
V8_Fatal(__FILE__, __LINE__, "unimplemented opcode: %x (%s)", opcode,
WasmOpcodes::OpcodeName(opcode));
return {0, 0};
}
#undef DECLARE_OPCODE_CASE
// clang-format on
}
};
#define CALL_INTERFACE(name, ...) interface_.name(this, ##__VA_ARGS__)
#define CALL_INTERFACE_IF_REACHABLE(name, ...) \
do { \
DCHECK(!control_.empty()); \
if (this->ok() && control_.back().reachable()) { \
interface_.name(this, ##__VA_ARGS__); \
} \
} while (false)
#define CALL_INTERFACE_IF_PARENT_REACHABLE(name, ...) \
do { \
DCHECK(!control_.empty()); \
if (this->ok() && (control_.size() == 1 || control_at(1)->reachable())) { \
interface_.name(this, ##__VA_ARGS__); \
} \
} while (false)
template <Decoder::ValidateFlag validate, typename Interface>
class WasmFullDecoder : public WasmDecoder<validate> {
using Value = typename Interface::Value;
using Control = typename Interface::Control;
using MergeValues = Merge<Value>;
// All Value types should be trivially copyable for performance. We push, pop,
// and store them in local variables.
static_assert(IS_TRIVIALLY_COPYABLE(Value),
"all Value<...> types should be trivially copyable");
public:
template <typename... InterfaceArgs>
WasmFullDecoder(Zone* zone, const wasm::WasmModule* module,
const FunctionBody& body, InterfaceArgs&&... interface_args)
: WasmDecoder<validate>(module, body.sig, body.start, body.end,
body.offset),
zone_(zone),
interface_(std::forward<InterfaceArgs>(interface_args)...),
local_type_vec_(zone),
stack_(zone),
control_(zone),
args_(zone),
last_end_found_(false) {
this->local_types_ = &local_type_vec_;
}
Interface& interface() { return interface_; }
bool Decode() {
DCHECK(stack_.empty());
DCHECK(control_.empty());
base::ElapsedTimer decode_timer;
if (FLAG_trace_wasm_decode_time) {
decode_timer.Start();
}
if (this->end_ < this->pc_) {
this->error("function body end < start");
return false;
}
DCHECK_EQ(0, this->local_types_->size());
WasmDecoder<validate>::DecodeLocals(this, this->sig_, this->local_types_);
CALL_INTERFACE(StartFunction);
DecodeFunctionBody();
if (!this->failed()) CALL_INTERFACE(FinishFunction);
if (this->failed()) return this->TraceFailed();
if (!control_.empty()) {
// Generate a better error message whether the unterminated control
// structure is the function body block or an innner structure.
if (control_.size() > 1) {
this->error(control_.back().pc, "unterminated control structure");
} else {
this->error("function body must end with \"end\" opcode");
}
return TraceFailed();
}
if (!last_end_found_) {
this->error("function body must end with \"end\" opcode");
return false;
}
if (FLAG_trace_wasm_decode_time) {
double ms = decode_timer.Elapsed().InMillisecondsF();
PrintF("wasm-decode %s (%0.3f ms)\n\n", this->ok() ? "ok" : "failed", ms);
} else {
TRACE("wasm-decode %s\n\n", this->ok() ? "ok" : "failed");
}
return true;
}
bool TraceFailed() {
TRACE("wasm-error module+%-6d func+%d: %s\n\n", this->error_offset_,
this->GetBufferRelativeOffset(this->error_offset_),
this->error_msg_.c_str());
return false;
}
const char* SafeOpcodeNameAt(const byte* pc) {
if (pc >= this->end_) return "<end>";
return WasmOpcodes::OpcodeName(static_cast<WasmOpcode>(*pc));
}
inline Zone* zone() const { return zone_; }
inline uint32_t NumLocals() {
return static_cast<uint32_t>(local_type_vec_.size());
}
inline ValueType GetLocalType(uint32_t index) {
return local_type_vec_[index];
}
inline wasm::WasmCodePosition position() {
int offset = static_cast<int>(this->pc_ - this->start_);
DCHECK_EQ(this->pc_ - this->start_, offset); // overflows cannot happen
return offset;
}
inline uint32_t control_depth() const {
return static_cast<uint32_t>(control_.size());
}
inline Control* control_at(uint32_t depth) {
DCHECK_GT(control_.size(), depth);
return &control_.back() - depth;
}
inline uint32_t stack_size() const {
DCHECK_GE(kMaxUInt32, stack_.size());
return static_cast<uint32_t>(stack_.size());
}
inline Value* stack_value(uint32_t depth) {
DCHECK_GT(stack_.size(), depth);
return &stack_[stack_.size() - depth - 1];
}
inline Value& GetMergeValueFromStack(
Control* c, Merge<Value>* merge, uint32_t i) {
DCHECK(merge == &c->start_merge || merge == &c->end_merge);
DCHECK_GT(merge->arity, i);
DCHECK_GE(stack_.size(), c->stack_depth + merge->arity);
return stack_[stack_.size() - merge->arity + i];
}
private:
static constexpr size_t kErrorMsgSize = 128;
Zone* zone_;
Interface interface_;
ZoneVector<ValueType> local_type_vec_; // types of local variables.
ZoneVector<Value> stack_; // stack of values.
ZoneVector<Control> control_; // stack of blocks, loops, and ifs.
ZoneVector<Value> args_; // parameters of current block or call
bool last_end_found_;
bool CheckHasMemory() {
if (!VALIDATE(this->module_->has_memory)) {
this->error(this->pc_ - 1, "memory instruction with no memory");
return false;
}
return true;
}
bool CheckHasSharedMemory() {
if (!VALIDATE(this->module_->has_shared_memory)) {
this->error(this->pc_ - 1, "Atomic opcodes used without shared memory");
return false;
}
return true;
}
class TraceLine {
public:
static constexpr int kMaxLen = 512;
~TraceLine() {
if (!FLAG_trace_wasm_decoder) return;
PrintF("%.*s\n", len_, buffer_);
}
// Appends a formatted string.
PRINTF_FORMAT(2, 3)
void Append(const char* format, ...) {
if (!FLAG_trace_wasm_decoder) return;
va_list va_args;
va_start(va_args, format);
size_t remaining_len = kMaxLen - len_;
Vector<char> remaining_msg_space(buffer_ + len_, remaining_len);
int len = VSNPrintF(remaining_msg_space, format, va_args);
va_end(va_args);
len_ += len < 0 ? remaining_len : len;
}
private:
char buffer_[kMaxLen];
int len_ = 0;
};
// Decodes the body of a function.
void DecodeFunctionBody() {
TRACE("wasm-decode %p...%p (module+%u, %d bytes)\n",
reinterpret_cast<const void*>(this->start()),
reinterpret_cast<const void*>(this->end()), this->pc_offset(),
static_cast<int>(this->end() - this->start()));
// Set up initial function block.
{
auto* c = PushBlock();
InitMerge(&c->start_merge, 0, [](uint32_t) -> Value { UNREACHABLE(); });
InitMerge(&c->end_merge,
static_cast<uint32_t>(this->sig_->return_count()),
[&] (uint32_t i) {
return Value::New(this->pc_, this->sig_->GetReturn(i)); });
CALL_INTERFACE(StartFunctionBody, c);
}
while (this->pc_ < this->end_) { // decoding loop.
unsigned len = 1;
WasmOpcode opcode = static_cast<WasmOpcode>(*this->pc_);
CALL_INTERFACE_IF_REACHABLE(NextInstruction, opcode);
#if DEBUG
TraceLine trace_msg;
#define TRACE_PART(...) trace_msg.Append(__VA_ARGS__)
if (!WasmOpcodes::IsPrefixOpcode(opcode)) {
TRACE_PART(TRACE_INST_FORMAT, startrel(this->pc_),
WasmOpcodes::OpcodeName(opcode));
}
#else
#define TRACE_PART(...)
#endif
FunctionSig* sig = WasmOpcodes::Signature(opcode);
if (sig) {
BuildSimpleOperator(opcode, sig);
} else {
// Complex bytecode.
switch (opcode) {
case kExprNop:
break;
case kExprBlock: {
BlockTypeOperand<validate> operand(this, this->pc_);
if (!LookupBlockType(&operand)) break;
PopArgs(operand.sig);
auto* block = PushBlock();
SetBlockType(block, operand, args_);
CALL_INTERFACE_IF_REACHABLE(Block, block);
PushMergeValues(block, &block->start_merge);
len = 1 + operand.length;
break;
}
case kExprRethrow: {
// TODO(kschimpf): Implement.
CHECK_PROTOTYPE_OPCODE(eh);
OPCODE_ERROR(opcode, "not implemented yet");
break;
}
case kExprThrow: {
CHECK_PROTOTYPE_OPCODE(eh);
ExceptionIndexOperand<Decoder::kValidate> operand(this, this->pc_);
len = 1 + operand.length;
if (!this->Validate(this->pc_, operand)) break;
PopArgs(operand.exception->ToFunctionSig());
CALL_INTERFACE_IF_REACHABLE(Throw, operand, &control_.back(),
vec2vec(args_));
EndControl();
break;
}
case kExprTry: {
CHECK_PROTOTYPE_OPCODE(eh);
BlockTypeOperand<validate> operand(this, this->pc_);
if (!LookupBlockType(&operand)) break;
PopArgs(operand.sig);
auto* try_block = PushTry();
SetBlockType(try_block, operand, args_);
len = 1 + operand.length;
CALL_INTERFACE_IF_REACHABLE(Try, try_block);
PushMergeValues(try_block, &try_block->start_merge);
break;
}
case kExprCatch: {
// TODO(kschimpf): Fix to use type signature of exception.
CHECK_PROTOTYPE_OPCODE(eh);
ExceptionIndexOperand<Decoder::kValidate> operand(this, this->pc_);
len = 1 + operand.length;
if (!this->Validate(this->pc_, operand)) break;
if (!VALIDATE(!control_.empty())) {
this->error("catch does not match any try");
break;
}
Control* c = &control_.back();
if (!VALIDATE(c->is_try())) {
this->error("catch does not match any try");
break;
}
if (!VALIDATE(c->is_incomplete_try())) {
OPCODE_ERROR(opcode, "multiple catch blocks not implemented");
break;
}
c->kind = kControlTryCatch;
FallThruTo(c);
stack_.resize(c->stack_depth);
const WasmExceptionSig* sig = operand.exception->sig;
for (size_t i = 0, e = sig->parameter_count(); i < e; ++i) {
Push(sig->GetParam(i));
}
Vector<Value> values(stack_.data() + c->stack_depth,
sig->parameter_count());
CALL_INTERFACE_IF_PARENT_REACHABLE(CatchException, operand, c,
values);
c->reachability = control_at(1)->innerReachability();
break;
}
case kExprCatchAll: {
// TODO(kschimpf): Implement.
CHECK_PROTOTYPE_OPCODE(eh);
OPCODE_ERROR(opcode, "not implemented yet");
break;
}
case kExprLoop: {
BlockTypeOperand<validate> operand(this, this->pc_);
if (!LookupBlockType(&operand)) break;
PopArgs(operand.sig);
auto* block = PushLoop();
SetBlockType(&control_.back(), operand, args_);
len = 1 + operand.length;
CALL_INTERFACE_IF_REACHABLE(Loop, block);
PushMergeValues(block, &block->start_merge);
break;
}
case kExprIf: {
BlockTypeOperand<validate> operand(this, this->pc_);
if (!LookupBlockType(&operand)) break;
auto cond = Pop(0, kWasmI32);
PopArgs(operand.sig);
if (!this->ok()) break;
auto* if_block = PushIf();
SetBlockType(if_block, operand, args_);
CALL_INTERFACE_IF_REACHABLE(If, cond, if_block);
len = 1 + operand.length;
PushMergeValues(if_block, &if_block->start_merge);
break;
}
case kExprElse: {
if (!VALIDATE(!control_.empty())) {
this->error("else does not match any if");
break;
}
Control* c = &control_.back();
if (!VALIDATE(c->is_if())) {
this->error(this->pc_, "else does not match an if");
break;
}
if (c->is_if_else()) {
this->error(this->pc_, "else already present for if");
break;
}
FallThruTo(c);
c->kind = kControlIfElse;
CALL_INTERFACE_IF_PARENT_REACHABLE(Else, c);
PushMergeValues(c, &c->start_merge);
c->reachability = control_at(1)->innerReachability();
break;
}
case kExprEnd: {
if (!VALIDATE(!control_.empty())) {
this->error("end does not match any if, try, or block");
return;
}
Control* c = &control_.back();
if (!VALIDATE(!c->is_incomplete_try())) {
this->error(this->pc_, "missing catch in try");
break;
}
if (c->is_onearmed_if()) {
// Emulate empty else arm.
FallThruTo(c);
if (this->failed()) break;
CALL_INTERFACE_IF_PARENT_REACHABLE(Else, c);
PushMergeValues(c, &c->start_merge);
c->reachability = control_at(1)->innerReachability();
}
FallThruTo(c);
// A loop just leaves the values on the stack.
if (!c->is_loop()) PushMergeValues(c, &c->end_merge);
if (control_.size() == 1) {
// If at the last (implicit) control, check we are at end.
if (!VALIDATE(this->pc_ + 1 == this->end_)) {
this->error(this->pc_ + 1, "trailing code after function end");
break;
}
last_end_found_ = true;
// The result of the block is the return value.
TRACE_PART("\n" TRACE_INST_FORMAT, startrel(this->pc_),
"(implicit) return");
DoReturn(c, true);
}
PopControl(c);
break;
}
case kExprSelect: {
auto cond = Pop(2, kWasmI32);
auto fval = Pop();
auto tval = Pop(0, fval.type);
auto* result = Push(tval.type == kWasmVar ? fval.type : tval.type);
CALL_INTERFACE_IF_REACHABLE(Select, cond, fval, tval, result);
break;
}
case kExprBr: {
BreakDepthOperand<validate> operand(this, this->pc_);
if (!this->Validate(this->pc_, operand, control_.size())) break;
Control* c = control_at(operand.depth);
if (!TypeCheckBreak(c)) break;
CALL_INTERFACE_IF_REACHABLE(Br, c);
BreakTo(c);
len = 1 + operand.length;
EndControl();
break;
}
case kExprBrIf: {
BreakDepthOperand<validate> operand(this, this->pc_);
auto cond = Pop(0, kWasmI32);
if (!this->Validate(this->pc_, operand, control_.size())) break;
Control* c = control_at(operand.depth);
if (!TypeCheckBreak(c)) break;
CALL_INTERFACE_IF_REACHABLE(BrIf, cond, c);
BreakTo(c);
len = 1 + operand.length;
break;
}
case kExprBrTable: {
BranchTableOperand<validate> operand(this, this->pc_);
BranchTableIterator<validate> iterator(this, operand);
if (!this->Validate(this->pc_, operand, control_.size())) break;
auto key = Pop(0, kWasmI32);
uint32_t br_arity = 0;
while (iterator.has_next()) {
const uint32_t i = iterator.cur_index();
const byte* pos = iterator.pc();
uint32_t target = iterator.next();
if (!VALIDATE(target < control_.size())) {
this->error(pos, "improper branch in br_table");
break;
}
// Check that label types match up.
Control* c = control_at(target);
uint32_t arity = c->br_merge()->arity;
if (i == 0) {
br_arity = arity;
} else if (!VALIDATE(br_arity == arity)) {
this->errorf(pos,
"inconsistent arity in br_table target %d"
" (previous was %u, this one %u)",
i, br_arity, arity);
}
if (!TypeCheckBreak(c)) break;
BreakTo(c);
}
CALL_INTERFACE_IF_REACHABLE(BrTable, operand, key);
len = 1 + iterator.length();
EndControl();
break;
}
case kExprReturn: {
DoReturn(&control_.back(), false);
break;
}
case kExprUnreachable: {
CALL_INTERFACE_IF_REACHABLE(Unreachable);
EndControl();
break;
}
case kExprI32Const: {
ImmI32Operand<validate> operand(this, this->pc_);
auto* value = Push(kWasmI32);
CALL_INTERFACE_IF_REACHABLE(I32Const, value, operand.value);
len = 1 + operand.length;
break;
}
case kExprI64Const: {
ImmI64Operand<validate> operand(this, this->pc_);
auto* value = Push(kWasmI64);
CALL_INTERFACE_IF_REACHABLE(I64Const, value, operand.value);
len = 1 + operand.length;
break;
}
case kExprF32Const: {
ImmF32Operand<validate> operand(this, this->pc_);
auto* value = Push(kWasmF32);
CALL_INTERFACE_IF_REACHABLE(F32Const, value, operand.value);
len = 1 + operand.length;
break;
}
case kExprF64Const: {
ImmF64Operand<validate> operand(this, this->pc_);
auto* value = Push(kWasmF64);
CALL_INTERFACE_IF_REACHABLE(F64Const, value, operand.value);
len = 1 + operand.length;
break;
}
case kExprGetLocal: {
LocalIndexOperand<Decoder::kValidate> operand(this, this->pc_);
if (!this->Validate(this->pc_, operand)) break;
auto* value = Push(operand.type);
CALL_INTERFACE_IF_REACHABLE(GetLocal, value, operand);
len = 1 + operand.length;
break;
}
case kExprSetLocal: {
LocalIndexOperand<Decoder::kValidate> operand(this, this->pc_);
if (!this->Validate(this->pc_, operand)) break;
auto value = Pop(0, local_type_vec_[operand.index]);
CALL_INTERFACE_IF_REACHABLE(SetLocal, value, operand);
len = 1 + operand.length;
break;
}
case kExprTeeLocal: {
LocalIndexOperand<Decoder::kValidate> operand(this, this->pc_);
if (!this->Validate(this->pc_, operand)) break;
auto value = Pop(0, local_type_vec_[operand.index]);
auto* result = Push(value.type);
CALL_INTERFACE_IF_REACHABLE(TeeLocal, value, result, operand);
len = 1 + operand.length;
break;
}
case kExprDrop: {
auto value = Pop();
CALL_INTERFACE_IF_REACHABLE(Drop, value);
break;
}
case kExprGetGlobal: {
GlobalIndexOperand<validate> operand(this, this->pc_);
len = 1 + operand.length;
if (!this->Validate(this->pc_, operand)) break;
auto* result = Push(operand.type);
CALL_INTERFACE_IF_REACHABLE(GetGlobal, result, operand);
break;
}
case kExprSetGlobal: {
GlobalIndexOperand<validate> operand(this, this->pc_);
len = 1 + operand.length;
if (!this->Validate(this->pc_, operand)) break;
if (!VALIDATE(operand.global->mutability)) {
this->errorf(this->pc_, "immutable global #%u cannot be assigned",
operand.index);
break;
}
auto value = Pop(0, operand.type);
CALL_INTERFACE_IF_REACHABLE(SetGlobal, value, operand);
break;
}
case kExprI32LoadMem8S:
len = 1 + DecodeLoadMem(LoadType::kI32Load8S);
break;
case kExprI32LoadMem8U:
len = 1 + DecodeLoadMem(LoadType::kI32Load8U);
break;
case kExprI32LoadMem16S:
len = 1 + DecodeLoadMem(LoadType::kI32Load16S);
break;
case kExprI32LoadMem16U:
len = 1 + DecodeLoadMem(LoadType::kI32Load16U);
break;
case kExprI32LoadMem:
len = 1 + DecodeLoadMem(LoadType::kI32Load);
break;
case kExprI64LoadMem8S:
len = 1 + DecodeLoadMem(LoadType::kI64Load8S);
break;
case kExprI64LoadMem8U:
len = 1 + DecodeLoadMem(LoadType::kI64Load8U);
break;
case kExprI64LoadMem16S:
len = 1 + DecodeLoadMem(LoadType::kI64Load16S);
break;
case kExprI64LoadMem16U:
len = 1 + DecodeLoadMem(LoadType::kI64Load16U);
break;
case kExprI64LoadMem32S:
len = 1 + DecodeLoadMem(LoadType::kI64Load32S);
break;
case kExprI64LoadMem32U:
len = 1 + DecodeLoadMem(LoadType::kI64Load32U);
break;
case kExprI64LoadMem:
len = 1 + DecodeLoadMem(LoadType::kI64Load);
break;
case kExprF32LoadMem:
len = 1 + DecodeLoadMem(LoadType::kF32Load);
break;
case kExprF64LoadMem:
len = 1 + DecodeLoadMem(LoadType::kF64Load);
break;
case kExprI32StoreMem8:
len = 1 + DecodeStoreMem(StoreType::kI32Store8);
break;
case kExprI32StoreMem16:
len = 1 + DecodeStoreMem(StoreType::kI32Store16);
break;
case kExprI32StoreMem:
len = 1 + DecodeStoreMem(StoreType::kI32Store);
break;
case kExprI64StoreMem8:
len = 1 + DecodeStoreMem(StoreType::kI64Store8);
break;
case kExprI64StoreMem16:
len = 1 + DecodeStoreMem(StoreType::kI64Store16);
break;
case kExprI64StoreMem32:
len = 1 + DecodeStoreMem(StoreType::kI64Store32);
break;
case kExprI64StoreMem:
len = 1 + DecodeStoreMem(StoreType::kI64Store);
break;
case kExprF32StoreMem:
len = 1 + DecodeStoreMem(StoreType::kF32Store);
break;
case kExprF64StoreMem:
len = 1 + DecodeStoreMem(StoreType::kF64Store);
break;
case kExprGrowMemory: {
if (!CheckHasMemory()) break;
MemoryIndexOperand<validate> operand(this, this->pc_);
len = 1 + operand.length;
DCHECK_NOT_NULL(this->module_);
if (!VALIDATE(this->module_->is_wasm())) {
this->error("grow_memory is not supported for asmjs modules");
break;
}
auto value = Pop(0, kWasmI32);
auto* result = Push(kWasmI32);
CALL_INTERFACE_IF_REACHABLE(GrowMemory, value, result);
break;
}
case kExprMemorySize: {
if (!CheckHasMemory()) break;
MemoryIndexOperand<validate> operand(this, this->pc_);
auto* result = Push(kWasmI32);
len = 1 + operand.length;
CALL_INTERFACE_IF_REACHABLE(CurrentMemoryPages, result);
break;
}
case kExprCallFunction: {
CallFunctionOperand<validate> operand(this, this->pc_);
len = 1 + operand.length;
if (!this->Validate(this->pc_, operand)) break;
// TODO(clemensh): Better memory management.
PopArgs(operand.sig);
auto* returns = PushReturns(operand.sig);
CALL_INTERFACE_IF_REACHABLE(CallDirect, operand, args_.data(),
returns);
break;
}
case kExprCallIndirect: {
CallIndirectOperand<validate> operand(this, this->pc_);
len = 1 + operand.length;
if (!this->Validate(this->pc_, operand)) break;
auto index = Pop(0, kWasmI32);
PopArgs(operand.sig);
auto* returns = PushReturns(operand.sig);
CALL_INTERFACE_IF_REACHABLE(CallIndirect, index, operand,
args_.data(), returns);
break;
}
case kNumericPrefix: {
CHECK_PROTOTYPE_OPCODE(sat_f2i_conversions);
++len;
byte numeric_index = this->template read_u8<validate>(
this->pc_ + 1, "numeric index");
opcode = static_cast<WasmOpcode>(opcode << 8 | numeric_index);
TRACE_PART(TRACE_INST_FORMAT, startrel(this->pc_),
WasmOpcodes::OpcodeName(opcode));
sig = WasmOpcodes::Signature(opcode);
if (sig == nullptr) {
this->errorf(this->pc_, "Unrecognized numeric opcode: %x\n",
opcode);
return;
}
BuildSimpleOperator(opcode, sig);
break;
}
case kSimdPrefix: {
CHECK_PROTOTYPE_OPCODE(simd);
len++;
byte simd_index =
this->template read_u8<validate>(this->pc_ + 1, "simd index");
opcode = static_cast<WasmOpcode>(opcode << 8 | simd_index);
TRACE_PART(TRACE_INST_FORMAT, startrel(this->pc_),
WasmOpcodes::OpcodeName(opcode));
len += DecodeSimdOpcode(opcode);
break;
}
case kAtomicPrefix: {
CHECK_PROTOTYPE_OPCODE(threads);
if (!CheckHasSharedMemory()) break;
len++;
byte atomic_index =
this->template read_u8<validate>(this->pc_ + 1, "atomic index");
opcode = static_cast<WasmOpcode>(opcode << 8 | atomic_index);
TRACE_PART(TRACE_INST_FORMAT, startrel(this->pc_),
WasmOpcodes::OpcodeName(opcode));
len += DecodeAtomicOpcode(opcode);
break;
}
default: {
// Deal with special asmjs opcodes.
if (this->module_ != nullptr && this->module_->is_asm_js()) {
sig = WasmOpcodes::AsmjsSignature(opcode);
if (sig) {
BuildSimpleOperator(opcode, sig);
}
} else {
this->error("Invalid opcode");
return;
}
}
}
}
#if DEBUG
if (FLAG_trace_wasm_decoder) {
TRACE_PART(" ");
for (Control& c : control_) {
switch (c.kind) {
case kControlIf:
TRACE_PART("I");
break;
case kControlBlock:
TRACE_PART("B");
break;
case kControlLoop:
TRACE_PART("L");
break;
case kControlTry:
TRACE_PART("T");
break;
default:
break;
}
if (c.start_merge.arity) TRACE_PART("%u-", c.start_merge.arity);
TRACE_PART("%u", c.end_merge.arity);
if (!c.reachable()) TRACE_PART("%c", c.unreachable() ? '*' : '#');
}
TRACE_PART(" | ");
for (size_t i = 0; i < stack_.size(); ++i) {
auto& val = stack_[i];
WasmOpcode opcode = static_cast<WasmOpcode>(*val.pc);
if (WasmOpcodes::IsPrefixOpcode(opcode)) {
opcode = static_cast<WasmOpcode>(opcode << 8 | *(val.pc + 1));
}
TRACE_PART(" %c@%d:%s", WasmOpcodes::ShortNameOf(val.type),
static_cast<int>(val.pc - this->start_),
WasmOpcodes::OpcodeName(opcode));
// If the decoder failed, don't try to decode the operands, as this
// can trigger a DCHECK failure.
if (this->failed()) continue;
switch (opcode) {
case kExprI32Const: {
ImmI32Operand<Decoder::kNoValidate> operand(this, val.pc);
TRACE_PART("[%d]", operand.value);
break;
}
case kExprGetLocal:
case kExprSetLocal:
case kExprTeeLocal: {
LocalIndexOperand<Decoder::kNoValidate> operand(this, val.pc);
TRACE_PART("[%u]", operand.index);
break;
}
case kExprGetGlobal:
case kExprSetGlobal: {
GlobalIndexOperand<Decoder::kNoValidate> operand(this, val.pc);
TRACE_PART("[%u]", operand.index);
break;
}
default:
break;
}
}
}
#endif
this->pc_ += len;
} // end decode loop
if (this->pc_ > this->end_ && this->ok()) this->error("Beyond end of code");
}
void EndControl() {
DCHECK(!control_.empty());
auto* current = &control_.back();
stack_.resize(current->stack_depth);
CALL_INTERFACE_IF_REACHABLE(EndControl, current);
current->reachability = kUnreachable;
}
bool LookupBlockType(BlockTypeOperand<validate>* operand) {
if (operand->type == kWasmVar) {
if (!VALIDATE(this->module_ &&
operand->sig_index < this->module_->signatures.size())) {
this->errorf(
this->pc_, "block type index %u out of bounds (%d signatures)",
operand->sig_index,
static_cast<int>(this->module_
? this->module_->signatures.size() : 0));
return false;
}
operand->sig = this->module_->signatures[operand->sig_index];
}
return true;
}
template<typename func>
void InitMerge(Merge<Value>* merge, uint32_t arity, func get_val) {
merge->arity = arity;
if (arity == 1) {
merge->vals.first = get_val(0);
} else if (arity > 1) {
merge->vals.array = zone_->NewArray<Value>(arity);
for (unsigned i = 0; i < arity; i++) {
merge->vals.array[i] = get_val(i);
}
}
}
void SetBlockType(Control* c, BlockTypeOperand<validate>& operand,
ZoneVector<Value>& params) {
InitMerge(&c->end_merge, operand.out_arity(),
[&] (uint32_t i) {
return Value::New(this->pc_, operand.out_type(i)); });
InitMerge(&c->start_merge, operand.in_arity(),
[&] (uint32_t i) { return params[i]; });
}
// Pops arguments as required by signature into {args_}.
V8_INLINE void PopArgs(FunctionSig* sig) {
int count = sig ? static_cast<int>(sig->parameter_count()) : 0;
args_.resize(count);
for (int i = count - 1; i >= 0; --i) {
args_[i] = Pop(i, sig->GetParam(i));
}
}
ValueType GetReturnType(FunctionSig* sig) {
DCHECK_GE(1, sig->return_count());
return sig->return_count() == 0 ? kWasmStmt : sig->GetReturn();
}
Control* PushControl(Control&& new_control) {
Reachability reachability =
control_.empty() ? kReachable : control_.back().innerReachability();
control_.emplace_back(std::move(new_control));
Control* c = &control_.back();
c->reachability = reachability;
c->start_merge.reached = c->reachable();
return c;
}
Control* PushBlock() {
return PushControl(Control::Block(this->pc_, stack_size()));
}
Control* PushLoop() {
return PushControl(Control::Loop(this->pc_, stack_size()));
}
Control* PushIf() {
return PushControl(Control::If(this->pc_, stack_size()));
}
Control* PushTry() {
// current_catch_ = static_cast<int32_t>(control_.size() - 1);
return PushControl(Control::Try(this->pc_, stack_size()));
}
void PopControl(Control* c) {
DCHECK_EQ(c, &control_.back());
CALL_INTERFACE_IF_PARENT_REACHABLE(PopControl, c);
bool reached = c->end_merge.reached;
control_.pop_back();
// If the parent block was reachable before, but the popped control does not
// return to here, this block becomes indirectly unreachable.
if (!control_.empty() && !reached && control_.back().reachable()) {
control_.back().reachability = kSpecOnlyReachable;
}
}
int DecodeLoadMem(LoadType type, int prefix_len = 0) {
if (!CheckHasMemory()) return 0;
MemoryAccessOperand<validate> operand(this, this->pc_ + prefix_len,
type.size_log_2());
auto index = Pop(0, kWasmI32);
auto* result = Push(type.value_type());
CALL_INTERFACE_IF_REACHABLE(LoadMem, type, operand, index, result);
return operand.length;
}
int DecodeStoreMem(StoreType store, int prefix_len = 0) {
if (!CheckHasMemory()) return 0;
MemoryAccessOperand<validate> operand(this, this->pc_ + prefix_len,
store.size_log_2());
auto value = Pop(1, store.value_type());
auto index = Pop(0, kWasmI32);
CALL_INTERFACE_IF_REACHABLE(StoreMem, store, operand, index, value);
return operand.length;
}
unsigned SimdExtractLane(WasmOpcode opcode, ValueType type) {
SimdLaneOperand<validate> operand(this, this->pc_);
if (this->Validate(this->pc_, opcode, operand)) {
Value inputs[] = {Pop(0, ValueType::kSimd128)};
auto* result = Push(type);
CALL_INTERFACE_IF_REACHABLE(SimdLaneOp, opcode, operand,
ArrayVector(inputs), result);
}
return operand.length;
}
unsigned SimdReplaceLane(WasmOpcode opcode, ValueType type) {
SimdLaneOperand<validate> operand(this, this->pc_);
if (this->Validate(this->pc_, opcode, operand)) {
Value inputs[2];
inputs[1] = Pop(1, type);
inputs[0] = Pop(0, ValueType::kSimd128);
auto* result = Push(ValueType::kSimd128);
CALL_INTERFACE_IF_REACHABLE(SimdLaneOp, opcode, operand,
ArrayVector(inputs), result);
}
return operand.length;
}
unsigned SimdShiftOp(WasmOpcode opcode) {
SimdShiftOperand<validate> operand(this, this->pc_);
if (this->Validate(this->pc_, opcode, operand)) {
auto input = Pop(0, ValueType::kSimd128);
auto* result = Push(ValueType::kSimd128);
CALL_INTERFACE_IF_REACHABLE(SimdShiftOp, opcode, operand, input, result);
}
return operand.length;
}
unsigned Simd8x16ShuffleOp() {
Simd8x16ShuffleOperand<validate> operand(this, this->pc_);
if (this->Validate(this->pc_, operand)) {
auto input1 = Pop(1, ValueType::kSimd128);
auto input0 = Pop(0, ValueType::kSimd128);
auto* result = Push(ValueType::kSimd128);
CALL_INTERFACE_IF_REACHABLE(Simd8x16ShuffleOp, operand, input0, input1,
result);
}
return 16;
}
unsigned DecodeSimdOpcode(WasmOpcode opcode) {
unsigned len = 0;
switch (opcode) {
case kExprF32x4ExtractLane: {
len = SimdExtractLane(opcode, ValueType::kFloat32);
break;
}
case kExprI32x4ExtractLane:
case kExprI16x8ExtractLane:
case kExprI8x16ExtractLane: {
len = SimdExtractLane(opcode, ValueType::kWord32);
break;
}
case kExprF32x4ReplaceLane: {
len = SimdReplaceLane(opcode, ValueType::kFloat32);
break;
}
case kExprI32x4ReplaceLane:
case kExprI16x8ReplaceLane:
case kExprI8x16ReplaceLane: {
len = SimdReplaceLane(opcode, ValueType::kWord32);
break;
}
case kExprI32x4Shl:
case kExprI32x4ShrS:
case kExprI32x4ShrU:
case kExprI16x8Shl:
case kExprI16x8ShrS:
case kExprI16x8ShrU:
case kExprI8x16Shl:
case kExprI8x16ShrS:
case kExprI8x16ShrU: {
len = SimdShiftOp(opcode);
break;
}
case kExprS8x16Shuffle: {
len = Simd8x16ShuffleOp();
break;
}
case kExprS128LoadMem:
len = DecodeLoadMem(LoadType::kS128Load, 1);
break;
case kExprS128StoreMem:
len = DecodeStoreMem(StoreType::kS128Store, 1);
break;
default: {
FunctionSig* sig = WasmOpcodes::Signature(opcode);
if (!VALIDATE(sig != nullptr)) {
this->error("invalid simd opcode");
break;
}
PopArgs(sig);
auto* results =
sig->return_count() == 0 ? nullptr : Push(GetReturnType(sig));
CALL_INTERFACE_IF_REACHABLE(SimdOp, opcode, vec2vec(args_), results);
}
}
return len;
}
unsigned DecodeAtomicOpcode(WasmOpcode opcode) {
unsigned len = 0;
ValueType ret_type;
FunctionSig* sig = WasmOpcodes::Signature(opcode);
if (sig != nullptr) {
MachineType memtype;
switch (opcode) {
#define CASE_ATOMIC_STORE_OP(Name, Type) \
case kExpr##Name: { \
memtype = MachineType::Type(); \
ret_type = MachineRepresentation::kNone; \
break; \
}
ATOMIC_STORE_OP_LIST(CASE_ATOMIC_STORE_OP)
#undef CASE_ATOMIC_OP
#define CASE_ATOMIC_OP(Name, Type) \
case kExpr##Name: { \
memtype = MachineType::Type(); \
ret_type = GetReturnType(sig); \
break; \
}
ATOMIC_OP_LIST(CASE_ATOMIC_OP)
#undef CASE_ATOMIC_OP
default:
this->error("invalid atomic opcode");
return 0;
}
MemoryAccessOperand<validate> operand(
this, this->pc_ + 1, ElementSizeLog2Of(memtype.representation()));
len += operand.length;
PopArgs(sig);
auto result = ret_type == MachineRepresentation::kNone
? nullptr
: Push(GetReturnType(sig));
CALL_INTERFACE_IF_REACHABLE(AtomicOp, opcode, vec2vec(args_), operand,
result);
} else {
this->error("invalid atomic opcode");
}
return len;
}
void DoReturn(Control* c, bool implicit) {
int return_count = static_cast<int>(this->sig_->return_count());
args_.resize(return_count);
// Pop return values off the stack in reverse order.
for (int i = return_count - 1; i >= 0; --i) {
args_[i] = Pop(i, this->sig_->GetReturn(i));
}
// Simulate that an implicit return morally comes after the current block.
if (implicit && c->end_merge.reached) c->reachability = kReachable;
CALL_INTERFACE_IF_REACHABLE(DoReturn, vec2vec(args_), implicit);
EndControl();
}
inline Value* Push(ValueType type) {
DCHECK_NE(kWasmStmt, type);
stack_.push_back(Value::New(this->pc_, type));
return &stack_.back();
}
void PushMergeValues(Control* c, Merge<Value>* merge) {
DCHECK_EQ(c, &control_.back());
DCHECK(merge == &c->start_merge || merge == &c->end_merge);
stack_.resize(c->stack_depth);
if (merge->arity == 1) {
stack_.push_back(merge->vals.first);
} else {
for (unsigned i = 0; i < merge->arity; i++) {
stack_.push_back(merge->vals.array[i]);
}
}
DCHECK_EQ(c->stack_depth + merge->arity, stack_.size());
}
Value* PushReturns(FunctionSig* sig) {
size_t return_count = sig->return_count();
if (return_count == 0) return nullptr;
size_t old_size = stack_.size();
for (size_t i = 0; i < return_count; ++i) {
Push(sig->GetReturn(i));
}
return stack_.data() + old_size;
}
Value Pop(int index, ValueType expected) {
auto val = Pop();
if (!VALIDATE(val.type == expected || val.type == kWasmVar ||
expected == kWasmVar)) {
this->errorf(val.pc, "%s[%d] expected type %s, found %s of type %s",
SafeOpcodeNameAt(this->pc_), index,
WasmOpcodes::TypeName(expected), SafeOpcodeNameAt(val.pc),
WasmOpcodes::TypeName(val.type));
}
return val;
}
Value Pop() {
DCHECK(!control_.empty());
uint32_t limit = control_.back().stack_depth;
if (stack_.size() <= limit) {
// Popping past the current control start in reachable code.
if (!VALIDATE(control_.back().unreachable())) {
this->errorf(this->pc_, "%s found empty stack",
SafeOpcodeNameAt(this->pc_));
}
return Value::Unreachable(this->pc_);
}
auto val = stack_.back();
stack_.pop_back();
return val;
}
int startrel(const byte* ptr) { return static_cast<int>(ptr - this->start_); }
inline void BreakTo(Control* c) {
if (control_.back().reachable()) c->br_merge()->reached = true;
}
void FallThruTo(Control* c) {
DCHECK_EQ(c, &control_.back());
if (!TypeCheckFallThru(c)) return;
if (!c->reachable()) return;
if (!c->is_loop()) CALL_INTERFACE(FallThruTo, c);
c->end_merge.reached = true;
}
bool TypeCheckMergeValues(Control* c, Merge<Value>* merge) {
DCHECK(merge == &c->start_merge || merge == &c->end_merge);
DCHECK_GE(stack_.size(), c->stack_depth + merge->arity);
// Typecheck the topmost {merge->arity} values on the stack.
for (uint32_t i = 0; i < merge->arity; ++i) {
auto& val = GetMergeValueFromStack(c, merge, i);
auto& old = (*merge)[i];
if (val.type != old.type) {
// If {val.type} is polymorphic, which results from unreachable, make
// it more specific by using the merge value's expected type.
// If it is not polymorphic, this is a type error.
if (!VALIDATE(val.type == kWasmVar)) {
this->errorf(
this->pc_, "type error in merge[%u] (expected %s, got %s)", i,
WasmOpcodes::TypeName(old.type), WasmOpcodes::TypeName(val.type));
return false;
}
val.type = old.type;
}
}
return true;
}
bool TypeCheckFallThru(Control* c) {
DCHECK_EQ(c, &control_.back());
if (!validate) return true;
uint32_t expected = c->end_merge.arity;
DCHECK_GE(stack_.size(), c->stack_depth);
uint32_t actual = static_cast<uint32_t>(stack_.size()) - c->stack_depth;
// Fallthrus must match the arity of the control exactly.
if (!InsertUnreachablesIfNecessary(expected, actual) || actual > expected) {
this->errorf(
this->pc_,
"expected %u elements on the stack for fallthru to @%d, found %u",
expected, startrel(c->pc), actual);
return false;
}
return TypeCheckMergeValues(c, &c->end_merge);
}
bool TypeCheckBreak(Control* c) {
// Breaks must have at least the number of values expected; can have more.
uint32_t expected = c->br_merge()->arity;
DCHECK_GE(stack_.size(), control_.back().stack_depth);
uint32_t actual =
static_cast<uint32_t>(stack_.size()) - control_.back().stack_depth;
if (!InsertUnreachablesIfNecessary(expected, actual)) {
this->errorf(this->pc_,
"expected %u elements on the stack for br to @%d, found %u",
expected, startrel(c->pc), actual);
return false;
}
return TypeCheckMergeValues(c, c->br_merge());
}
inline bool InsertUnreachablesIfNecessary(uint32_t expected,
uint32_t actual) {
if (V8_LIKELY(actual >= expected)) {
return true; // enough actual values are there.
}
if (!VALIDATE(control_.back().unreachable())) {
// There aren't enough values on the stack.
return false;
}
// A slow path. When the actual number of values on the stack is less
// than the expected number of values and the current control is
// unreachable, insert unreachable values below the actual values.
// This simplifies {TypeCheckMergeValues}.
auto pos = stack_.begin() + (stack_.size() - actual);
stack_.insert(pos, (expected - actual), Value::Unreachable(this->pc_));
return true;
}
virtual void onFirstError() {
this->end_ = this->pc_; // Terminate decoding loop.
TRACE(" !%s\n", this->error_msg_.c_str());
CALL_INTERFACE(OnFirstError);
}
inline void BuildSimpleOperator(WasmOpcode opcode, FunctionSig* sig) {
switch (sig->parameter_count()) {
case 1: {
auto val = Pop(0, sig->GetParam(0));
auto* ret =
sig->return_count() == 0 ? nullptr : Push(sig->GetReturn(0));
CALL_INTERFACE_IF_REACHABLE(UnOp, opcode, sig, val, ret);
break;
}
case 2: {
auto rval = Pop(1, sig->GetParam(1));
auto lval = Pop(0, sig->GetParam(0));
auto* ret =
sig->return_count() == 0 ? nullptr : Push(sig->GetReturn(0));
CALL_INTERFACE_IF_REACHABLE(BinOp, opcode, sig, lval, rval, ret);
break;
}
default:
UNREACHABLE();
}
}
};
#undef CALL_INTERFACE
#undef CALL_INTERFACE_IF_REACHABLE
#undef CALL_INTERFACE_IF_PARENT_REACHABLE
class EmptyInterface {
public:
static constexpr wasm::Decoder::ValidateFlag validate =
wasm::Decoder::kValidate;
using Value = ValueBase;
using Control = ControlBase<Value>;
using Decoder = WasmFullDecoder<validate, EmptyInterface>;
#define DEFINE_EMPTY_CALLBACK(name, ...) \
void name(Decoder* decoder, ##__VA_ARGS__) {}
INTERFACE_FUNCTIONS(DEFINE_EMPTY_CALLBACK)
#undef DEFINE_EMPTY_CALLBACK
};
#undef TRACE
#undef TRACE_INST_FORMAT
#undef VALIDATE
#undef CHECK_PROTOTYPE_OPCODE
#undef OPCODE_ERROR
} // namespace wasm
} // namespace internal
} // namespace v8
#endif // V8_WASM_FUNCTION_BODY_DECODER_IMPL_H_