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chromium / v8 / v8 / d126e3fc5561a774cf5e4c70441ac585b2131e74 / . / src / wasm / function-body-decoder.cc
blob: 92a84ac27072fd7cf7a768bb2da26f4fe52ed41b [file] [log] [blame]
// Copyright 2015 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.
#include "src/signature.h"
#include "src/base/platform/elapsed-timer.h"
#include "src/bit-vector.h"
#include "src/flags.h"
#include "src/handles.h"
#include "src/objects-inl.h"
#include "src/zone/zone-containers.h"
#include "src/wasm/decoder.h"
#include "src/wasm/function-body-decoder-impl.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"
#include "src/ostreams.h"
#include "src/compiler/wasm-compiler.h"
namespace v8 {
namespace internal {
namespace wasm {
#if DEBUG
#define TRACE(...) \
do { \
if (FLAG_trace_wasm_decoder) PrintF(__VA_ARGS__); \
} while (false)
#else
#define TRACE(...)
#endif
#define CHECK_PROTOTYPE_OPCODE(flag) \
if (module_ != nullptr && module_->origin == kAsmJsOrigin) { \
error("Opcode not supported for asmjs modules"); \
} \
if (!FLAG_##flag) { \
error("Invalid opcode (enable with --" #flag ")"); \
break; \
}
// An SsaEnv environment carries the current local variable renaming
// as well as the current effect and control dependency in the TF graph.
// It maintains a control state that tracks whether the environment
// is reachable, has reached a control end, or has been merged.
struct SsaEnv {
enum State { kControlEnd, kUnreachable, kReached, kMerged };
State state;
TFNode* control;
TFNode* effect;
TFNode** locals;
bool go() { return state >= kReached; }
void Kill(State new_state = kControlEnd) {
state = new_state;
locals = nullptr;
control = nullptr;
effect = nullptr;
}
void SetNotMerged() {
if (state == kMerged) state = kReached;
}
};
// An entry on the value stack.
struct Value {
const byte* pc;
TFNode* node;
ValueType type;
};
struct TryInfo : public ZoneObject {
SsaEnv* catch_env;
TFNode* exception;
explicit TryInfo(SsaEnv* c) : catch_env(c), exception(nullptr) {}
};
struct MergeValues {
uint32_t arity;
union {
Value* array;
Value first;
} vals; // Either multiple values or a single value.
Value& operator[](size_t i) {
DCHECK_GT(arity, i);
return arity == 1 ? vals.first : vals.array[i];
}
};
static Value* NO_VALUE = nullptr;
enum ControlKind { kControlIf, kControlBlock, kControlLoop, kControlTry };
// An entry on the control stack (i.e. if, block, loop).
struct Control {
const byte* pc;
ControlKind kind;
size_t stack_depth; // stack height at the beginning of the construct.
SsaEnv* end_env; // end environment for the construct.
SsaEnv* false_env; // false environment (only for if).
TryInfo* try_info; // Information used for compiling try statements.
int32_t previous_catch; // The previous Control (on the stack) with a catch.
bool unreachable; // The current block has been ended.
// Values merged into the end of this control construct.
MergeValues merge;
inline bool is_if() const { return kind == kControlIf; }
inline bool is_block() const { return kind == kControlBlock; }
inline bool is_loop() const { return kind == kControlLoop; }
inline bool is_try() const { return kind == kControlTry; }
// Named constructors.
static Control Block(const byte* pc, size_t stack_depth, SsaEnv* end_env,
int32_t previous_catch) {
return {pc, kControlBlock, stack_depth, end_env, nullptr,
nullptr, previous_catch, false, {0, {NO_VALUE}}};
}
static Control If(const byte* pc, size_t stack_depth, SsaEnv* end_env,
SsaEnv* false_env, int32_t previous_catch) {
return {pc, kControlIf, stack_depth, end_env, false_env,
nullptr, previous_catch, false, {0, {NO_VALUE}}};
}
static Control Loop(const byte* pc, size_t stack_depth, SsaEnv* end_env,
int32_t previous_catch) {
return {pc, kControlLoop, stack_depth, end_env, nullptr,
nullptr, previous_catch, false, {0, {NO_VALUE}}};
}
static Control Try(const byte* pc, size_t stack_depth, SsaEnv* end_env,
Zone* zone, SsaEnv* catch_env, int32_t previous_catch) {
DCHECK_NOT_NULL(catch_env);
TryInfo* try_info = new (zone) TryInfo(catch_env);
return {pc, kControlTry, stack_depth, end_env, nullptr,
try_info, previous_catch, false, {0, {NO_VALUE}}};
}
};
// Macros that build nodes only if there is a graph and the current SSA
// environment is reachable from start. This avoids problems with malformed
// TF graphs when decoding inputs that have unreachable code.
#define BUILD(func, ...) \
(build() ? CheckForException(builder_->func(__VA_ARGS__)) : nullptr)
#define BUILD0(func) (build() ? CheckForException(builder_->func()) : nullptr)
// Generic Wasm bytecode decoder with utilities for decoding operands,
// lengths, etc.
class WasmDecoder : public Decoder {
public:
WasmDecoder(const WasmModule* module, FunctionSig* sig, const byte* start,
const byte* end)
: Decoder(start, end),
module_(module),
sig_(sig),
local_types_(nullptr) {}
const WasmModule* module_;
FunctionSig* sig_;
ZoneVector<ValueType>* local_types_;
size_t total_locals() const {
return local_types_ == nullptr ? 0 : local_types_->size();
}
static bool DecodeLocals(Decoder* decoder, const FunctionSig* sig,
ZoneVector<ValueType>* type_list) {
DCHECK_NOT_NULL(type_list);
// Initialize from signature.
if (sig != nullptr) {
type_list->reserve(sig->parameter_count());
for (size_t i = 0; i < sig->parameter_count(); ++i) {
type_list->push_back(sig->GetParam(i));
}
}
// 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:
type = kWasmS128;
break;
case kLocalS1x4:
type = kWasmS1x4;
break;
case kLocalS1x8:
type = kWasmS1x8;
break;
case kLocalS1x16:
type = kWasmS1x16;
break;
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,
int locals_count, Zone* zone) {
if (pc >= decoder->end()) return nullptr;
if (*pc != kExprLoop) return nullptr;
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 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 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& operand) {
if (operand.index < total_locals()) {
if (local_types_) {
operand.type = local_types_->at(operand.index);
} else {
operand.type = kWasmStmt;
}
return true;
}
error(pc, pc + 1, "invalid local index: %u", operand.index);
return false;
}
inline bool Validate(const byte* pc, GlobalIndexOperand& operand) {
if (module_ != nullptr && operand.index < module_->globals.size()) {
operand.global = &module_->globals[operand.index];
operand.type = operand.global->type;
return true;
}
error(pc, pc + 1, "invalid global index: %u", operand.index);
return false;
}
inline bool Complete(const byte* pc, CallFunctionOperand& operand) {
if (module_ != nullptr && operand.index < module_->functions.size()) {
operand.sig = module_->functions[operand.index].sig;
return true;
}
return false;
}
inline bool Validate(const byte* pc, CallFunctionOperand& operand) {
if (Complete(pc, operand)) {
return true;
}
error(pc, pc + 1, "invalid function index: %u", operand.index);
return false;
}
inline bool Complete(const byte* pc, CallIndirectOperand& operand) {
if (module_ != nullptr && operand.index < module_->signatures.size()) {
operand.sig = module_->signatures[operand.index];
return true;
}
return false;
}
inline bool Validate(const byte* pc, CallIndirectOperand& operand) {
if (module_ == nullptr || module_->function_tables.empty()) {
error("function table has to exist to execute call_indirect");
return false;
}
if (Complete(pc, operand)) {
return true;
}
error(pc, pc + 1, "invalid signature index: #%u", operand.index);
return false;
}
inline bool Validate(const byte* pc, BreakDepthOperand& operand,
ZoneVector<Control>& control) {
if (operand.depth < control.size()) {
operand.target = &control[control.size() - operand.depth - 1];
return true;
}
error(pc, pc + 1, "invalid break depth: %u", operand.depth);
return false;
}
bool Validate(const byte* pc, BranchTableOperand& operand,
size_t block_depth) {
// TODO(titzer): add extra redundant validation for br_table here?
return true;
}
inline bool Validate(const byte* pc, WasmOpcode opcode,
SimdLaneOperand& 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 (operand.lane < 0 || operand.lane >= num_lanes) {
error(pc_, pc_ + 2, "invalid lane index");
return false;
} else {
return true;
}
}
inline bool Validate(const byte* pc, WasmOpcode opcode,
SimdShiftOperand& 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 (operand.shift < 0 || operand.shift >= max_shift) {
error(pc_, pc_ + 2, "invalid shift amount");
return false;
} else {
return true;
}
}
static unsigned OpcodeLength(Decoder* decoder, const byte* pc) {
switch (static_cast<byte>(*pc)) {
#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 operand(decoder, pc, UINT32_MAX);
return 1 + operand.length;
}
case kExprBr:
case kExprBrIf: {
BreakDepthOperand operand(decoder, pc);
return 1 + operand.length;
}
case kExprSetGlobal:
case kExprGetGlobal: {
GlobalIndexOperand operand(decoder, pc);
return 1 + operand.length;
}
case kExprCallFunction: {
CallFunctionOperand operand(decoder, pc);
return 1 + operand.length;
}
case kExprCallIndirect: {
CallIndirectOperand operand(decoder, pc);
return 1 + operand.length;
}
case kExprTry:
case kExprIf: // fall thru
case kExprLoop:
case kExprBlock: {
BlockTypeOperand operand(decoder, pc);
return 1 + operand.length;
}
case kExprSetLocal:
case kExprTeeLocal:
case kExprGetLocal:
case kExprCatch: {
LocalIndexOperand operand(decoder, pc);
return 1 + operand.length;
}
case kExprBrTable: {
BranchTableOperand operand(decoder, pc);
BranchTableIterator iterator(decoder, operand);
return 1 + iterator.length();
}
case kExprI32Const: {
ImmI32Operand operand(decoder, pc);
return 1 + operand.length;
}
case kExprI64Const: {
ImmI64Operand operand(decoder, pc);
return 1 + operand.length;
}
case kExprGrowMemory:
case kExprMemorySize: {
MemoryIndexOperand operand(decoder, pc);
return 1 + operand.length;
}
case kExprF32Const:
return 5;
case kExprF64Const:
return 9;
case kSimdPrefix: {
byte simd_index = decoder->checked_read_u8(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;
}
default:
decoder->error(pc, "invalid SIMD opcode");
return 2;
}
}
default:
return 1;
}
}
};
static const int32_t kNullCatch = -1;
// The full WASM decoder for bytecode. Verifies bytecode and, optionally,
// generates a TurboFan IR graph.
class WasmFullDecoder : public WasmDecoder {
public:
WasmFullDecoder(Zone* zone, const wasm::WasmModule* module,
const FunctionBody& body)
: WasmFullDecoder(zone, module, nullptr, body) {}
WasmFullDecoder(Zone* zone, TFBuilder* builder, const FunctionBody& body)
: WasmFullDecoder(zone, builder->module_env() == nullptr
? nullptr
: builder->module_env()->module,
builder, body) {}
bool Decode() {
if (FLAG_wasm_code_fuzzer_gen_test) {
PrintRawWasmCode(start_, end_);
}
base::ElapsedTimer decode_timer;
if (FLAG_trace_wasm_decode_time) {
decode_timer.Start();
}
stack_.clear();
control_.clear();
if (end_ < pc_) {
error("function body end < start");
return false;
}
DCHECK_EQ(0, local_types_->size());
WasmDecoder::DecodeLocals(this, sig_, local_types_);
InitSsaEnv();
DecodeFunctionBody();
if (failed()) return 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) {
error(pc_, control_.back().pc, "unterminated control structure");
} else {
error("function body must end with \"end\" opcode.");
}
return TraceFailed();
}
if (!last_end_found_) {
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", ok() ? "ok" : "failed", ms);
} else {
TRACE("wasm-decode %s\n\n", ok() ? "ok" : "failed");
}
return true;
}
bool TraceFailed() {
TRACE("wasm-error module+%-6d func+%d: %s\n\n", baserel(error_pc_),
startrel(error_pc_), error_msg_.get());
return false;
}
private:
WasmFullDecoder(Zone* zone, const wasm::WasmModule* module,
TFBuilder* builder, const FunctionBody& body)
: WasmDecoder(module, body.sig, body.start, body.end),
zone_(zone),
builder_(builder),
base_(body.base),
local_type_vec_(zone),
stack_(zone),
control_(zone),
last_end_found_(false),
current_catch_(kNullCatch) {
local_types_ = &local_type_vec_;
}
static const size_t kErrorMsgSize = 128;
Zone* zone_;
TFBuilder* builder_;
const byte* base_;
SsaEnv* ssa_env_;
ZoneVector<ValueType> local_type_vec_; // types of local variables.
ZoneVector<Value> stack_; // stack of values.
ZoneVector<Control> control_; // stack of blocks, loops, and ifs.
bool last_end_found_;
int32_t current_catch_;
TryInfo* current_try_info() { return control_[current_catch_].try_info; }
inline bool build() { return builder_ && ssa_env_->go(); }
void InitSsaEnv() {
TFNode* start = nullptr;
SsaEnv* ssa_env = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv)));
size_t size = sizeof(TFNode*) * EnvironmentCount();
ssa_env->state = SsaEnv::kReached;
ssa_env->locals =
size > 0 ? reinterpret_cast<TFNode**>(zone_->New(size)) : nullptr;
if (builder_) {
start = builder_->Start(static_cast<int>(sig_->parameter_count() + 1));
// Initialize local variables.
uint32_t index = 0;
while (index < sig_->parameter_count()) {
ssa_env->locals[index] = builder_->Param(index);
index++;
}
while (index < local_type_vec_.size()) {
ValueType type = local_type_vec_[index];
TFNode* node = DefaultValue(type);
while (index < local_type_vec_.size() &&
local_type_vec_[index] == type) {
// Do a whole run of like-typed locals at a time.
ssa_env->locals[index++] = node;
}
}
}
ssa_env->control = start;
ssa_env->effect = start;
SetEnv("initial", ssa_env);
if (builder_) {
// The function-prologue stack check is associated with position 0, which
// is never a position of any instruction in the function.
builder_->StackCheck(0);
}
}
TFNode* DefaultValue(ValueType type) {
switch (type) {
case kWasmI32:
return builder_->Int32Constant(0);
case kWasmI64:
return builder_->Int64Constant(0);
case kWasmF32:
return builder_->Float32Constant(0);
case kWasmF64:
return builder_->Float64Constant(0);
case kWasmS128:
return builder_->Simd128Zero();
case kWasmS1x4:
return builder_->Simd1x4Zero();
case kWasmS1x8:
return builder_->Simd1x8Zero();
case kWasmS1x16:
return builder_->Simd1x16Zero();
default:
UNREACHABLE();
return nullptr;
}
}
char* indentation() {
static const int kMaxIndent = 64;
static char bytes[kMaxIndent + 1];
for (int i = 0; i < kMaxIndent; ++i) bytes[i] = ' ';
bytes[kMaxIndent] = 0;
if (stack_.size() < kMaxIndent / 2) {
bytes[stack_.size() * 2] = 0;
}
return bytes;
}
bool CheckHasMemory() {
if (!module_->has_memory) {
error(pc_ - 1, "memory instruction with no memory");
}
return module_->has_memory;
}
// Decodes the body of a function.
void DecodeFunctionBody() {
TRACE("wasm-decode %p...%p (module+%d, %d bytes) %s\n",
reinterpret_cast<const void*>(start_),
reinterpret_cast<const void*>(end_), baserel(pc_),
static_cast<int>(end_ - start_), builder_ ? "graph building" : "");
{
// Set up initial function block.
SsaEnv* break_env = ssa_env_;
SetEnv("initial env", Steal(break_env));
PushBlock(break_env);
Control* c = &control_.back();
c->merge.arity = static_cast<uint32_t>(sig_->return_count());
if (c->merge.arity == 1) {
c->merge.vals.first = {pc_, nullptr, sig_->GetReturn(0)};
} else if (c->merge.arity > 1) {
c->merge.vals.array = zone_->NewArray<Value>(c->merge.arity);
for (unsigned i = 0; i < c->merge.arity; i++) {
c->merge.vals.array[i] = {pc_, nullptr, sig_->GetReturn(i)};
}
}
}
while (pc_ < end_) { // decoding loop.
unsigned len = 1;
WasmOpcode opcode = static_cast<WasmOpcode>(*pc_);
#if DEBUG
if (FLAG_trace_wasm_decoder && !WasmOpcodes::IsPrefixOpcode(opcode)) {
TRACE(" @%-8d #%-20s|", startrel(pc_),
WasmOpcodes::OpcodeName(opcode));
}
#endif
FunctionSig* sig = WasmOpcodes::Signature(opcode);
if (sig) {
BuildSimpleOperator(opcode, sig);
} else {
// Complex bytecode.
switch (opcode) {
case kExprNop:
break;
case kExprBlock: {
// The break environment is the outer environment.
BlockTypeOperand operand(this, pc_);
SsaEnv* break_env = ssa_env_;
PushBlock(break_env);
SetEnv("block:start", Steal(break_env));
SetBlockType(&control_.back(), operand);
len = 1 + operand.length;
break;
}
case kExprThrow: {
CHECK_PROTOTYPE_OPCODE(wasm_eh_prototype);
Value value = Pop(0, kWasmI32);
BUILD(Throw, value.node);
// TODO(titzer): Throw should end control, but currently we build a
// (reachable) runtime call instead of connecting it directly to
// end.
// EndControl();
break;
}
case kExprTry: {
CHECK_PROTOTYPE_OPCODE(wasm_eh_prototype);
BlockTypeOperand operand(this, pc_);
SsaEnv* outer_env = ssa_env_;
SsaEnv* try_env = Steal(outer_env);
SsaEnv* catch_env = UnreachableEnv();
PushTry(outer_env, catch_env);
SetEnv("try_catch:start", try_env);
SetBlockType(&control_.back(), operand);
len = 1 + operand.length;
break;
}
case kExprCatch: {
CHECK_PROTOTYPE_OPCODE(wasm_eh_prototype);
LocalIndexOperand operand(this, pc_);
len = 1 + operand.length;
if (control_.empty()) {
error("catch does not match any try");
break;
}
Control* c = &control_.back();
if (!c->is_try()) {
error("catch does not match any try");
break;
}
if (c->try_info->catch_env == nullptr) {
error(pc_, "catch already present for try with catch");
break;
}
FallThruTo(c);
stack_.resize(c->stack_depth);
DCHECK_NOT_NULL(c->try_info);
SsaEnv* catch_env = c->try_info->catch_env;
c->try_info->catch_env = nullptr;
SetEnv("catch:begin", catch_env);
current_catch_ = c->previous_catch;
if (Validate(pc_, operand)) {
if (ssa_env_->locals) {
TFNode* exception_as_i32 =
BUILD(Catch, c->try_info->exception, position());
ssa_env_->locals[operand.index] = exception_as_i32;
}
}
break;
}
case kExprLoop: {
BlockTypeOperand operand(this, pc_);
SsaEnv* finish_try_env = Steal(ssa_env_);
// The continue environment is the inner environment.
SsaEnv* loop_body_env = PrepareForLoop(pc_, finish_try_env);
SetEnv("loop:start", loop_body_env);
ssa_env_->SetNotMerged();
PushLoop(finish_try_env);
SetBlockType(&control_.back(), operand);
len = 1 + operand.length;
break;
}
case kExprIf: {
// Condition on top of stack. Split environments for branches.
BlockTypeOperand operand(this, pc_);
Value cond = Pop(0, kWasmI32);
TFNode* if_true = nullptr;
TFNode* if_false = nullptr;
BUILD(BranchNoHint, cond.node, &if_true, &if_false);
SsaEnv* end_env = ssa_env_;
SsaEnv* false_env = Split(ssa_env_);
false_env->control = if_false;
SsaEnv* true_env = Steal(ssa_env_);
true_env->control = if_true;
PushIf(end_env, false_env);
SetEnv("if:true", true_env);
SetBlockType(&control_.back(), operand);
len = 1 + operand.length;
break;
}
case kExprElse: {
if (control_.empty()) {
error("else does not match any if");
break;
}
Control* c = &control_.back();
if (!c->is_if()) {
error(pc_, c->pc, "else does not match an if");
break;
}
if (c->false_env == nullptr) {
error(pc_, c->pc, "else already present for if");
break;
}
FallThruTo(c);
stack_.resize(c->stack_depth);
// Switch to environment for false branch.
SetEnv("if_else:false", c->false_env);
c->false_env = nullptr; // record that an else is already seen
break;
}
case kExprEnd: {
if (control_.empty()) {
error("end does not match any if, try, or block");
return;
}
const char* name = "block:end";
Control* c = &control_.back();
if (c->is_loop()) {
// A loop just leaves the values on the stack.
TypeCheckFallThru(c);
if (c->unreachable) PushEndValues(c);
PopControl();
SetEnv("loop:end", ssa_env_);
break;
}
if (c->is_if()) {
if (c->false_env != nullptr) {
// End the true branch of a one-armed if.
Goto(c->false_env, c->end_env);
if (!c->unreachable && stack_.size() != c->stack_depth) {
error("end of if expected empty stack");
stack_.resize(c->stack_depth);
}
if (c->merge.arity > 0) {
error("non-void one-armed if");
}
name = "if:merge";
} else {
// End the false branch of a two-armed if.
name = "if_else:merge";
}
} else if (c->is_try()) {
name = "try:end";
// validate that catch was seen.
if (c->try_info->catch_env != nullptr) {
error(pc_, "missing catch in try");
break;
}
}
FallThruTo(c);
SetEnv(name, c->end_env);
PushEndValues(c);
if (control_.size() == 1) {
// If at the last (implicit) control, check we are at end.
if (pc_ + 1 != end_) {
error(pc_, pc_ + 1, "trailing code after function end");
break;
}
last_end_found_ = true;
if (ssa_env_->go()) {
// The result of the block is the return value.
TRACE(" @%-8d #xx:%-20s|", startrel(pc_), "(implicit) return");
DoReturn();
TRACE("\n");
} else {
TypeCheckFallThru(c);
}
}
PopControl();
break;
}
case kExprSelect: {
Value cond = Pop(2, kWasmI32);
Value fval = Pop();
Value tval = Pop(0, fval.type);
if (build()) {
TFNode* controls[2];
builder_->BranchNoHint(cond.node, &controls[0], &controls[1]);
TFNode* merge = builder_->Merge(2, controls);
TFNode* vals[2] = {tval.node, fval.node};
TFNode* phi = builder_->Phi(tval.type, 2, vals, merge);
Push(tval.type, phi);
ssa_env_->control = merge;
} else {
Push(tval.type == kWasmVar ? fval.type : tval.type, nullptr);
}
break;
}
case kExprBr: {
BreakDepthOperand operand(this, pc_);
if (Validate(pc_, operand, control_)) {
BreakTo(operand.depth);
}
len = 1 + operand.length;
EndControl();
break;
}
case kExprBrIf: {
BreakDepthOperand operand(this, pc_);
Value cond = Pop(0, kWasmI32);
if (ok() && Validate(pc_, operand, control_)) {
SsaEnv* fenv = ssa_env_;
SsaEnv* tenv = Split(fenv);
fenv->SetNotMerged();
BUILD(BranchNoHint, cond.node, &tenv->control, &fenv->control);
ssa_env_ = tenv;
BreakTo(operand.depth);
ssa_env_ = fenv;
}
len = 1 + operand.length;
break;
}
case kExprBrTable: {
BranchTableOperand operand(this, pc_);
BranchTableIterator iterator(this, operand);
if (Validate(pc_, operand, control_.size())) {
Value key = Pop(0, kWasmI32);
if (failed()) break;
SsaEnv* break_env = ssa_env_;
if (operand.table_count > 0) {
// Build branches to the various blocks based on the table.
TFNode* sw = BUILD(Switch, operand.table_count + 1, key.node);
SsaEnv* copy = Steal(break_env);
ssa_env_ = copy;
MergeValues* merge = nullptr;
while (ok() && iterator.has_next()) {
uint32_t i = iterator.cur_index();
const byte* pos = iterator.pc();
uint32_t target = iterator.next();
if (target >= control_.size()) {
error(pos, "improper branch in br_table");
break;
}
ssa_env_ = Split(copy);
ssa_env_->control = (i == operand.table_count)
? BUILD(IfDefault, sw)
: BUILD(IfValue, i, sw);
BreakTo(target);
// Check that label types match up.
Control* c = &control_[control_.size() - target - 1];
if (i == 0) {
merge = &c->merge;
} else if (merge->arity != c->merge.arity) {
error(pos, pos, "inconsistent arity in br_table target %d"
" (previous was %u, this one %u)",
i, merge->arity, c->merge.arity);
} else if (control_.back().unreachable) {
for (uint32_t j = 0; ok() && j < merge->arity; ++j) {
if ((*merge)[j].type != c->merge[j].type) {
error(pos, pos,
"type error in br_table target %d operand %d"
" (previous expected %s, this one %s)", i, j,
WasmOpcodes::TypeName((*merge)[j].type),
WasmOpcodes::TypeName(c->merge[j].type));
}
}
}
}
if (failed()) break;
} else {
// Only a default target. Do the equivalent of br.
const byte* pos = iterator.pc();
uint32_t target = iterator.next();
if (target >= control_.size()) {
error(pos, "improper branch in br_table");
break;
}
BreakTo(target);
}
// br_table ends the control flow like br.
ssa_env_ = break_env;
}
len = 1 + iterator.length();
EndControl();
break;
}
case kExprReturn: {
DoReturn();
break;
}
case kExprUnreachable: {
BUILD(Unreachable, position());
EndControl();
break;
}
case kExprI32Const: {
ImmI32Operand operand(this, pc_);
Push(kWasmI32, BUILD(Int32Constant, operand.value));
len = 1 + operand.length;
break;
}
case kExprI64Const: {
ImmI64Operand operand(this, pc_);
Push(kWasmI64, BUILD(Int64Constant, operand.value));
len = 1 + operand.length;
break;
}
case kExprF32Const: {
ImmF32Operand operand(this, pc_);
Push(kWasmF32, BUILD(Float32Constant, operand.value));
len = 1 + operand.length;
break;
}
case kExprF64Const: {
ImmF64Operand operand(this, pc_);
Push(kWasmF64, BUILD(Float64Constant, operand.value));
len = 1 + operand.length;
break;
}
case kExprGetLocal: {
LocalIndexOperand operand(this, pc_);
if (Validate(pc_, operand)) {
if (build()) {
Push(operand.type, ssa_env_->locals[operand.index]);
} else {
Push(operand.type, nullptr);
}
}
len = 1 + operand.length;
break;
}
case kExprSetLocal: {
LocalIndexOperand operand(this, pc_);
if (Validate(pc_, operand)) {
Value val = Pop(0, local_type_vec_[operand.index]);
if (ssa_env_->locals) ssa_env_->locals[operand.index] = val.node;
}
len = 1 + operand.length;
break;
}
case kExprTeeLocal: {
LocalIndexOperand operand(this, pc_);
if (Validate(pc_, operand)) {
Value val = Pop(0, local_type_vec_[operand.index]);
if (ssa_env_->locals) ssa_env_->locals[operand.index] = val.node;
Push(val.type, val.node);
}
len = 1 + operand.length;
break;
}
case kExprDrop: {
Pop();
break;
}
case kExprGetGlobal: {
GlobalIndexOperand operand(this, pc_);
if (Validate(pc_, operand)) {
Push(operand.type, BUILD(GetGlobal, operand.index));
}
len = 1 + operand.length;
break;
}
case kExprSetGlobal: {
GlobalIndexOperand operand(this, pc_);
if (Validate(pc_, operand)) {
if (operand.global->mutability) {
Value val = Pop(0, operand.type);
BUILD(SetGlobal, operand.index, val.node);
} else {
error(pc_, pc_ + 1, "immutable global #%u cannot be assigned",
operand.index);
}
}
len = 1 + operand.length;
break;
}
case kExprI32LoadMem8S:
len = DecodeLoadMem(kWasmI32, MachineType::Int8());
break;
case kExprI32LoadMem8U:
len = DecodeLoadMem(kWasmI32, MachineType::Uint8());
break;
case kExprI32LoadMem16S:
len = DecodeLoadMem(kWasmI32, MachineType::Int16());
break;
case kExprI32LoadMem16U:
len = DecodeLoadMem(kWasmI32, MachineType::Uint16());
break;
case kExprI32LoadMem:
len = DecodeLoadMem(kWasmI32, MachineType::Int32());
break;
case kExprI64LoadMem8S:
len = DecodeLoadMem(kWasmI64, MachineType::Int8());
break;
case kExprI64LoadMem8U:
len = DecodeLoadMem(kWasmI64, MachineType::Uint8());
break;
case kExprI64LoadMem16S:
len = DecodeLoadMem(kWasmI64, MachineType::Int16());
break;
case kExprI64LoadMem16U:
len = DecodeLoadMem(kWasmI64, MachineType::Uint16());
break;
case kExprI64LoadMem32S:
len = DecodeLoadMem(kWasmI64, MachineType::Int32());
break;
case kExprI64LoadMem32U:
len = DecodeLoadMem(kWasmI64, MachineType::Uint32());
break;
case kExprI64LoadMem:
len = DecodeLoadMem(kWasmI64, MachineType::Int64());
break;
case kExprF32LoadMem:
len = DecodeLoadMem(kWasmF32, MachineType::Float32());
break;
case kExprF64LoadMem:
len = DecodeLoadMem(kWasmF64, MachineType::Float64());
break;
case kExprI32StoreMem8:
len = DecodeStoreMem(kWasmI32, MachineType::Int8());
break;
case kExprI32StoreMem16:
len = DecodeStoreMem(kWasmI32, MachineType::Int16());
break;
case kExprI32StoreMem:
len = DecodeStoreMem(kWasmI32, MachineType::Int32());
break;
case kExprI64StoreMem8:
len = DecodeStoreMem(kWasmI64, MachineType::Int8());
break;
case kExprI64StoreMem16:
len = DecodeStoreMem(kWasmI64, MachineType::Int16());
break;
case kExprI64StoreMem32:
len = DecodeStoreMem(kWasmI64, MachineType::Int32());
break;
case kExprI64StoreMem:
len = DecodeStoreMem(kWasmI64, MachineType::Int64());
break;
case kExprF32StoreMem:
len = DecodeStoreMem(kWasmF32, MachineType::Float32());
break;
case kExprF64StoreMem:
len = DecodeStoreMem(kWasmF64, MachineType::Float64());
break;
case kExprGrowMemory: {
if (!CheckHasMemory()) break;
MemoryIndexOperand operand(this, pc_);
DCHECK_NOT_NULL(module_);
if (module_->origin != kAsmJsOrigin) {
Value val = Pop(0, kWasmI32);
Push(kWasmI32, BUILD(GrowMemory, val.node));
} else {
error("grow_memory is not supported for asmjs modules");
}
len = 1 + operand.length;
break;
}
case kExprMemorySize: {
if (!CheckHasMemory()) break;
MemoryIndexOperand operand(this, pc_);
Push(kWasmI32, BUILD(CurrentMemoryPages));
len = 1 + operand.length;
break;
}
case kExprCallFunction: {
CallFunctionOperand operand(this, pc_);
if (Validate(pc_, operand)) {
TFNode** buffer = PopArgs(operand.sig);
TFNode** rets = nullptr;
BUILD(CallDirect, operand.index, buffer, &rets, position());
PushReturns(operand.sig, rets);
}
len = 1 + operand.length;
break;
}
case kExprCallIndirect: {
CallIndirectOperand operand(this, pc_);
if (Validate(pc_, operand)) {
Value index = Pop(0, kWasmI32);
TFNode** buffer = PopArgs(operand.sig);
if (buffer) buffer[0] = index.node;
TFNode** rets = nullptr;
BUILD(CallIndirect, operand.index, buffer, &rets, position());
PushReturns(operand.sig, rets);
}
len = 1 + operand.length;
break;
}
case kSimdPrefix: {
CHECK_PROTOTYPE_OPCODE(wasm_simd_prototype);
len++;
byte simd_index = checked_read_u8(pc_, 1, "simd index");
opcode = static_cast<WasmOpcode>(opcode << 8 | simd_index);
TRACE(" @%-4d #%-20s|", startrel(pc_),
WasmOpcodes::OpcodeName(opcode));
len += DecodeSimdOpcode(opcode);
break;
}
case kAtomicPrefix: {
if (module_ == nullptr || module_->origin != kAsmJsOrigin) {
error("Atomics are allowed only in AsmJs modules");
break;
}
if (!FLAG_wasm_atomics_prototype) {
error("Invalid opcode (enable with --wasm_atomics_prototype)");
break;
}
len = 2;
byte atomic_opcode = checked_read_u8(pc_, 1, "atomic index");
opcode = static_cast<WasmOpcode>(opcode << 8 | atomic_opcode);
sig = WasmOpcodes::AtomicSignature(opcode);
if (sig) {
BuildAtomicOperator(opcode);
}
break;
}
default: {
// Deal with special asmjs opcodes.
if (module_ != nullptr && module_->origin == kAsmJsOrigin) {
sig = WasmOpcodes::AsmjsSignature(opcode);
if (sig) {
BuildSimpleOperator(opcode, sig);
}
} else {
error("Invalid opcode");
return;
}
}
}
}
#if DEBUG
if (FLAG_trace_wasm_decoder) {
PrintF(" ");
for (size_t i = 0; i < control_.size(); ++i) {
Control* c = &control_[i];
enum ControlKind {
kControlIf,
kControlBlock,
kControlLoop,
kControlTry
};
switch (c->kind) {
case kControlIf:
PrintF("I");
break;
case kControlBlock:
PrintF("B");
break;
case kControlLoop:
PrintF("L");
break;
case kControlTry:
PrintF("T");
break;
default:
break;
}
PrintF("%u", c->merge.arity);
if (c->unreachable) PrintF("*");
}
PrintF(" | ");
for (size_t i = 0; i < stack_.size(); ++i) {
Value& val = stack_[i];
WasmOpcode opcode = static_cast<WasmOpcode>(*val.pc);
if (WasmOpcodes::IsPrefixOpcode(opcode)) {
opcode = static_cast<WasmOpcode>(opcode << 8 | *(val.pc + 1));
}
PrintF(" %c@%d:%s", WasmOpcodes::ShortNameOf(val.type),
static_cast<int>(val.pc - start_),
WasmOpcodes::OpcodeName(opcode));
switch (opcode) {
case kExprI32Const: {
ImmI32Operand operand(this, val.pc);
PrintF("[%d]", operand.value);
break;
}
case kExprGetLocal: {
LocalIndexOperand operand(this, val.pc);
PrintF("[%u]", operand.index);
break;
}
case kExprSetLocal: // fallthru
case kExprTeeLocal: {
LocalIndexOperand operand(this, val.pc);
PrintF("[%u]", operand.index);
break;
}
default:
break;
}
if (val.node == nullptr) PrintF("?");
}
PrintF("\n");
}
#endif
pc_ += len;
} // end decode loop
if (pc_ > end_ && ok()) error("Beyond end of code");
}
void EndControl() {
ssa_env_->Kill(SsaEnv::kControlEnd);
if (!control_.empty()) {
stack_.resize(control_.back().stack_depth);
control_.back().unreachable = true;
}
}
void SetBlockType(Control* c, BlockTypeOperand& operand) {
c->merge.arity = operand.arity;
if (c->merge.arity == 1) {
c->merge.vals.first = {pc_, nullptr, operand.read_entry(0)};
} else if (c->merge.arity > 1) {
c->merge.vals.array = zone_->NewArray<Value>(c->merge.arity);
for (unsigned i = 0; i < c->merge.arity; i++) {
c->merge.vals.array[i] = {pc_, nullptr, operand.read_entry(i)};
}
}
}
TFNode** PopArgs(FunctionSig* sig) {
if (build()) {
int count = static_cast<int>(sig->parameter_count());
TFNode** buffer = builder_->Buffer(count + 1);
buffer[0] = nullptr; // reserved for code object or function index.
for (int i = count - 1; i >= 0; i--) {
buffer[i + 1] = Pop(i, sig->GetParam(i)).node;
}
return buffer;
} else {
int count = static_cast<int>(sig->parameter_count());
for (int i = count - 1; i >= 0; i--) {
Pop(i, sig->GetParam(i));
}
return nullptr;
}
}
ValueType GetReturnType(FunctionSig* sig) {
return sig->return_count() == 0 ? kWasmStmt : sig->GetReturn();
}
void PushBlock(SsaEnv* end_env) {
control_.emplace_back(
Control::Block(pc_, stack_.size(), end_env, current_catch_));
}
void PushLoop(SsaEnv* end_env) {
control_.emplace_back(
Control::Loop(pc_, stack_.size(), end_env, current_catch_));
}
void PushIf(SsaEnv* end_env, SsaEnv* false_env) {
control_.emplace_back(
Control::If(pc_, stack_.size(), end_env, false_env, current_catch_));
}
void PushTry(SsaEnv* end_env, SsaEnv* catch_env) {
control_.emplace_back(Control::Try(pc_, stack_.size(), end_env, zone_,
catch_env, current_catch_));
current_catch_ = static_cast<int32_t>(control_.size() - 1);
}
void PopControl() { control_.pop_back(); }
int DecodeLoadMem(ValueType type, MachineType mem_type) {
if (!CheckHasMemory()) return 0;
MemoryAccessOperand operand(this, pc_,
ElementSizeLog2Of(mem_type.representation()));
Value index = Pop(0, kWasmI32);
TFNode* node = BUILD(LoadMem, type, mem_type, index.node, operand.offset,
operand.alignment, position());
Push(type, node);
return 1 + operand.length;
}
int DecodeStoreMem(ValueType type, MachineType mem_type) {
if (!CheckHasMemory()) return 0;
MemoryAccessOperand operand(this, pc_,
ElementSizeLog2Of(mem_type.representation()));
Value val = Pop(1, type);
Value index = Pop(0, kWasmI32);
BUILD(StoreMem, mem_type, index.node, operand.offset, operand.alignment,
val.node, position());
return 1 + operand.length;
}
unsigned SimdExtractLane(WasmOpcode opcode, ValueType type) {
SimdLaneOperand operand(this, pc_);
if (Validate(pc_, opcode, operand)) {
compiler::NodeVector inputs(1, zone_);
inputs[0] = Pop(0, ValueType::kSimd128).node;
TFNode* node = BUILD(SimdLaneOp, opcode, operand.lane, inputs);
Push(type, node);
}
return operand.length;
}
unsigned SimdReplaceLane(WasmOpcode opcode, ValueType type) {
SimdLaneOperand operand(this, pc_);
if (Validate(pc_, opcode, operand)) {
compiler::NodeVector inputs(2, zone_);
inputs[1] = Pop(1, type).node;
inputs[0] = Pop(0, ValueType::kSimd128).node;
TFNode* node = BUILD(SimdLaneOp, opcode, operand.lane, inputs);
Push(ValueType::kSimd128, node);
}
return operand.length;
}
unsigned SimdShiftOp(WasmOpcode opcode) {
SimdShiftOperand operand(this, pc_);
if (Validate(pc_, opcode, operand)) {
compiler::NodeVector inputs(1, zone_);
inputs[0] = Pop(0, ValueType::kSimd128).node;
TFNode* node = BUILD(SimdShiftOp, opcode, operand.shift, inputs);
Push(ValueType::kSimd128, node);
}
return operand.length;
}
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;
}
default: {
FunctionSig* sig = WasmOpcodes::Signature(opcode);
if (sig != nullptr) {
compiler::NodeVector inputs(sig->parameter_count(), zone_);
for (size_t i = sig->parameter_count(); i > 0; i--) {
Value val = Pop(static_cast<int>(i - 1), sig->GetParam(i - 1));
inputs[i - 1] = val.node;
}
TFNode* node = BUILD(SimdOp, opcode, inputs);
Push(GetReturnType(sig), node);
} else {
error("invalid simd opcode");
}
}
}
return len;
}
void BuildAtomicOperator(WasmOpcode opcode) { UNIMPLEMENTED(); }
void DoReturn() {
int count = static_cast<int>(sig_->return_count());
TFNode** buffer = nullptr;
if (build()) buffer = builder_->Buffer(count);
// Pop return values off the stack in reverse order.
for (int i = count - 1; i >= 0; i--) {
Value val = Pop(i, sig_->GetReturn(i));
if (buffer) buffer[i] = val.node;
}
BUILD(Return, count, buffer);
EndControl();
}
void Push(ValueType type, TFNode* node) {
if (type != kWasmStmt) {
stack_.push_back({pc_, node, type});
}
}
void PushEndValues(Control* c) {
DCHECK_EQ(c, &control_.back());
stack_.resize(c->stack_depth);
if (c->merge.arity == 1) {
stack_.push_back(c->merge.vals.first);
} else {
for (unsigned i = 0; i < c->merge.arity; i++) {
stack_.push_back(c->merge.vals.array[i]);
}
}
DCHECK_EQ(c->stack_depth + c->merge.arity, stack_.size());
}
void PushReturns(FunctionSig* sig, TFNode** rets) {
for (size_t i = 0; i < sig->return_count(); i++) {
// When verifying only, then {rets} will be null, so push null.
Push(sig->GetReturn(i), rets ? rets[i] : nullptr);
}
}
const char* SafeOpcodeNameAt(const byte* pc) {
if (pc >= end_) return "<end>";
return WasmOpcodes::OpcodeName(static_cast<WasmOpcode>(*pc));
}
Value Pop(int index, ValueType expected) {
Value val = Pop();
if (val.type != expected && val.type != kWasmVar && expected != kWasmVar) {
error(pc_, val.pc, "%s[%d] expected type %s, found %s of type %s",
SafeOpcodeNameAt(pc_), index, WasmOpcodes::TypeName(expected),
SafeOpcodeNameAt(val.pc), WasmOpcodes::TypeName(val.type));
}
return val;
}
Value Pop() {
size_t limit = control_.empty() ? 0 : control_.back().stack_depth;
if (stack_.size() <= limit) {
// Popping past the current control start in reachable code.
Value val = {pc_, nullptr, kWasmVar};
if (!control_.back().unreachable) {
error(pc_, pc_, "%s found empty stack", SafeOpcodeNameAt(pc_));
}
return val;
}
Value val = stack_.back();
stack_.pop_back();
return val;
}
int baserel(const byte* ptr) {
return base_ ? static_cast<int>(ptr - base_) : 0;
}
int startrel(const byte* ptr) { return static_cast<int>(ptr - start_); }
void BreakTo(unsigned depth) {
Control* c = &control_[control_.size() - depth - 1];
if (c->is_loop()) {
// This is the inner loop block, which does not have a value.
Goto(ssa_env_, c->end_env);
} else {
// Merge the value(s) into the end of the block.
size_t expected = control_.back().stack_depth + c->merge.arity;
if (stack_.size() < expected && !control_.back().unreachable) {
error(
pc_, pc_,
"expected at least %u values on the stack for br to @%d, found %d",
c->merge.arity, startrel(c->pc),
static_cast<int>(stack_.size() - c->stack_depth));
return;
}
MergeValuesInto(c);
}
}
void FallThruTo(Control* c) {
DCHECK_EQ(c, &control_.back());
// Merge the value(s) into the end of the block.
size_t expected = c->stack_depth + c->merge.arity;
if (stack_.size() == expected ||
(stack_.size() < expected && c->unreachable)) {
MergeValuesInto(c);
c->unreachable = false;
return;
}
error(pc_, pc_, "expected %u elements on the stack for fallthru to @%d",
c->merge.arity, startrel(c->pc));
}
inline Value& GetMergeValueFromStack(Control* c, size_t i) {
return stack_[stack_.size() - c->merge.arity + i];
}
void TypeCheckFallThru(Control* c) {
DCHECK_EQ(c, &control_.back());
// Fallthru must match arity exactly.
int arity = static_cast<int>(c->merge.arity);
if (c->stack_depth + arity < stack_.size() ||
(c->stack_depth + arity != stack_.size() && !c->unreachable)) {
error(pc_, pc_, "expected %d elements on the stack for fallthru to @%d",
arity, startrel(c->pc));
return;
}
// Typecheck the values left on the stack.
size_t avail = stack_.size() - c->stack_depth;
for (size_t i = avail >= c->merge.arity ? 0 : c->merge.arity - avail;
i < c->merge.arity; i++) {
Value& val = GetMergeValueFromStack(c, i);
Value& old = c->merge[i];
if (val.type != old.type) {
error(pc_, pc_, "type error in merge[%zu] (expected %s, got %s)", i,
WasmOpcodes::TypeName(old.type), WasmOpcodes::TypeName(val.type));
return;
}
}
}
void MergeValuesInto(Control* c) {
SsaEnv* target = c->end_env;
bool first = target->state == SsaEnv::kUnreachable;
bool reachable = ssa_env_->go();
Goto(ssa_env_, target);
size_t avail = stack_.size() - control_.back().stack_depth;
for (size_t i = avail >= c->merge.arity ? 0 : c->merge.arity - avail;
i < c->merge.arity; i++) {
Value& val = GetMergeValueFromStack(c, i);
Value& old = c->merge[i];
if (val.type != old.type && val.type != kWasmVar) {
error(pc_, pc_, "type error in merge[%zu] (expected %s, got %s)", i,
WasmOpcodes::TypeName(old.type), WasmOpcodes::TypeName(val.type));
return;
}
if (builder_ && reachable) {
DCHECK_NOT_NULL(val.node);
old.node =
first ? val.node : CreateOrMergeIntoPhi(old.type, target->control,
old.node, val.node);
}
}
}
void SetEnv(const char* reason, SsaEnv* env) {
#if DEBUG
if (FLAG_trace_wasm_decoder) {
char state = 'X';
if (env) {
switch (env->state) {
case SsaEnv::kReached:
state = 'R';
break;
case SsaEnv::kUnreachable:
state = 'U';
break;
case SsaEnv::kMerged:
state = 'M';
break;
case SsaEnv::kControlEnd:
state = 'E';
break;
}
}
PrintF("{set_env = %p, state = %c, reason = %s", static_cast<void*>(env),
state, reason);
if (env && env->control) {
PrintF(", control = ");
compiler::WasmGraphBuilder::PrintDebugName(env->control);
}
PrintF("}");
}
#endif
ssa_env_ = env;
if (builder_) {
builder_->set_control_ptr(&env->control);
builder_->set_effect_ptr(&env->effect);
}
}
TFNode* CheckForException(TFNode* node) {
if (node == nullptr) {
return nullptr;
}
const bool inside_try_scope = current_catch_ != kNullCatch;
if (!inside_try_scope) {
return node;
}
TFNode* if_success = nullptr;
TFNode* if_exception = nullptr;
if (!builder_->ThrowsException(node, &if_success, &if_exception)) {
return node;
}
SsaEnv* success_env = Steal(ssa_env_);
success_env->control = if_success;
SsaEnv* exception_env = Split(success_env);
exception_env->control = if_exception;
TryInfo* try_info = current_try_info();
Goto(exception_env, try_info->catch_env);
TFNode* exception = try_info->exception;
if (exception == nullptr) {
DCHECK_EQ(SsaEnv::kReached, try_info->catch_env->state);
try_info->exception = if_exception;
} else {
DCHECK_EQ(SsaEnv::kMerged, try_info->catch_env->state);
try_info->exception =
CreateOrMergeIntoPhi(kWasmI32, try_info->catch_env->control,
try_info->exception, if_exception);
}
SetEnv("if_success", success_env);
return node;
}
void Goto(SsaEnv* from, SsaEnv* to) {
DCHECK_NOT_NULL(to);
if (!from->go()) return;
switch (to->state) {
case SsaEnv::kUnreachable: { // Overwrite destination.
to->state = SsaEnv::kReached;
to->locals = from->locals;
to->control = from->control;
to->effect = from->effect;
break;
}
case SsaEnv::kReached: { // Create a new merge.
to->state = SsaEnv::kMerged;
if (!builder_) break;
// Merge control.
TFNode* controls[] = {to->control, from->control};
TFNode* merge = builder_->Merge(2, controls);
to->control = merge;
// Merge effects.
if (from->effect != to->effect) {
TFNode* effects[] = {to->effect, from->effect, merge};
to->effect = builder_->EffectPhi(2, effects, merge);
}
// Merge SSA values.
for (int i = EnvironmentCount() - 1; i >= 0; i--) {
TFNode* a = to->locals[i];
TFNode* b = from->locals[i];
if (a != b) {
TFNode* vals[] = {a, b};
to->locals[i] = builder_->Phi(local_type_vec_[i], 2, vals, merge);
}
}
break;
}
case SsaEnv::kMerged: {
if (!builder_) break;
TFNode* merge = to->control;
// Extend the existing merge.
builder_->AppendToMerge(merge, from->control);
// Merge effects.
if (builder_->IsPhiWithMerge(to->effect, merge)) {
builder_->AppendToPhi(to->effect, from->effect);
} else if (to->effect != from->effect) {
uint32_t count = builder_->InputCount(merge);
TFNode** effects = builder_->Buffer(count);
for (uint32_t j = 0; j < count - 1; j++) {
effects[j] = to->effect;
}
effects[count - 1] = from->effect;
to->effect = builder_->EffectPhi(count, effects, merge);
}
// Merge locals.
for (int i = EnvironmentCount() - 1; i >= 0; i--) {
TFNode* tnode = to->locals[i];
TFNode* fnode = from->locals[i];
if (builder_->IsPhiWithMerge(tnode, merge)) {
builder_->AppendToPhi(tnode, fnode);
} else if (tnode != fnode) {
uint32_t count = builder_->InputCount(merge);
TFNode** vals = builder_->Buffer(count);
for (uint32_t j = 0; j < count - 1; j++) {
vals[j] = tnode;
}
vals[count - 1] = fnode;
to->locals[i] =
builder_->Phi(local_type_vec_[i], count, vals, merge);
}
}
break;
}
default:
UNREACHABLE();
}
return from->Kill();
}
TFNode* CreateOrMergeIntoPhi(ValueType type, TFNode* merge, TFNode* tnode,
TFNode* fnode) {
DCHECK_NOT_NULL(builder_);
if (builder_->IsPhiWithMerge(tnode, merge)) {
builder_->AppendToPhi(tnode, fnode);
} else if (tnode != fnode) {
uint32_t count = builder_->InputCount(merge);
TFNode** vals = builder_->Buffer(count);
for (uint32_t j = 0; j < count - 1; j++) vals[j] = tnode;
vals[count - 1] = fnode;
return builder_->Phi(type, count, vals, merge);
}
return tnode;
}
SsaEnv* PrepareForLoop(const byte* pc, SsaEnv* env) {
if (!builder_) return Split(env);
if (!env->go()) return Split(env);
env->state = SsaEnv::kMerged;
env->control = builder_->Loop(env->control);
env->effect = builder_->EffectPhi(1, &env->effect, env->control);
builder_->Terminate(env->effect, env->control);
if (FLAG_wasm_loop_assignment_analysis) {
BitVector* assigned = AnalyzeLoopAssignment(
this, pc, static_cast<int>(total_locals()), zone_);
if (failed()) return env;
if (assigned != nullptr) {
// Only introduce phis for variables assigned in this loop.
for (int i = EnvironmentCount() - 1; i >= 0; i--) {
if (!assigned->Contains(i)) continue;
env->locals[i] = builder_->Phi(local_type_vec_[i], 1, &env->locals[i],
env->control);
}
SsaEnv* loop_body_env = Split(env);
builder_->StackCheck(position(), &(loop_body_env->effect),
&(loop_body_env->control));
return loop_body_env;
}
}
// Conservatively introduce phis for all local variables.
for (int i = EnvironmentCount() - 1; i >= 0; i--) {
env->locals[i] =
builder_->Phi(local_type_vec_[i], 1, &env->locals[i], env->control);
}
SsaEnv* loop_body_env = Split(env);
builder_->StackCheck(position(), &(loop_body_env->effect),
&(loop_body_env->control));
return loop_body_env;
}
// Create a complete copy of the {from}.
SsaEnv* Split(SsaEnv* from) {
DCHECK_NOT_NULL(from);
SsaEnv* result = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv)));
size_t size = sizeof(TFNode*) * EnvironmentCount();
result->control = from->control;
result->effect = from->effect;
if (from->go()) {
result->state = SsaEnv::kReached;
result->locals =
size > 0 ? reinterpret_cast<TFNode**>(zone_->New(size)) : nullptr;
memcpy(result->locals, from->locals, size);
} else {
result->state = SsaEnv::kUnreachable;
result->locals = nullptr;
}
return result;
}
// Create a copy of {from} that steals its state and leaves {from}
// unreachable.
SsaEnv* Steal(SsaEnv* from) {
DCHECK_NOT_NULL(from);
if (!from->go()) return UnreachableEnv();
SsaEnv* result = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv)));
result->state = SsaEnv::kReached;
result->locals = from->locals;
result->control = from->control;
result->effect = from->effect;
from->Kill(SsaEnv::kUnreachable);
return result;
}
// Create an unreachable environment.
SsaEnv* UnreachableEnv() {
SsaEnv* result = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv)));
result->state = SsaEnv::kUnreachable;
result->control = nullptr;
result->effect = nullptr;
result->locals = nullptr;
return result;
}
int EnvironmentCount() {
if (builder_) return static_cast<int>(local_type_vec_.size());
return 0; // if we aren't building a graph, don't bother with SSA renaming.
}
virtual void onFirstError() {
end_ = start_; // Terminate decoding loop.
builder_ = nullptr; // Don't build any more nodes.
TRACE(" !%s\n", error_msg_.get());
}
inline wasm::WasmCodePosition position() {
int offset = static_cast<int>(pc_ - start_);
DCHECK_EQ(pc_ - start_, offset); // overflows cannot happen
return offset;
}
inline void BuildSimpleOperator(WasmOpcode opcode, FunctionSig* sig) {
TFNode* node;
switch (sig->parameter_count()) {
case 1: {
Value val = Pop(0, sig->GetParam(0));
node = BUILD(Unop, opcode, val.node, position());
break;
}
case 2: {
Value rval = Pop(1, sig->GetParam(1));
Value lval = Pop(0, sig->GetParam(0));
node = BUILD(Binop, opcode, lval.node, rval.node, position());
break;
}
default:
UNREACHABLE();
node = nullptr;
break;
}
Push(GetReturnType(sig), node);
}
};
bool DecodeLocalDecls(BodyLocalDecls* decls, const byte* start,
const byte* end) {
Decoder decoder(start, end);
if (WasmDecoder::DecodeLocals(&decoder, nullptr, &decls->type_list)) {
DCHECK(decoder.ok());
decls->encoded_size = decoder.pc_offset();
return true;
}
return false;
}
BytecodeIterator::BytecodeIterator(const byte* start, const byte* end,
BodyLocalDecls* decls)
: Decoder(start, end) {
if (decls != nullptr) {
if (DecodeLocalDecls(decls, start, end)) {
pc_ += decls->encoded_size;
if (pc_ > end_) pc_ = end_;
}
}
}
DecodeResult VerifyWasmCode(AccountingAllocator* allocator,
const wasm::WasmModule* module,
FunctionBody& body) {
Zone zone(allocator, ZONE_NAME);
WasmFullDecoder decoder(&zone, module, body);
decoder.Decode();
return decoder.toResult<DecodeStruct*>(nullptr);
}
DecodeResult BuildTFGraph(AccountingAllocator* allocator, TFBuilder* builder,
FunctionBody& body) {
Zone zone(allocator, ZONE_NAME);
WasmFullDecoder decoder(&zone, builder, body);
decoder.Decode();
return decoder.toResult<DecodeStruct*>(nullptr);
}
unsigned OpcodeLength(const byte* pc, const byte* end) {
Decoder decoder(pc, end);
return WasmDecoder::OpcodeLength(&decoder, pc);
}
void PrintRawWasmCode(const byte* start, const byte* end) {
AccountingAllocator allocator;
PrintRawWasmCode(&allocator, FunctionBodyForTesting(start, end), nullptr);
}
namespace {
const char* RawOpcodeName(WasmOpcode opcode) {
switch (opcode) {
#define DECLARE_NAME_CASE(name, opcode, sig) \
case kExpr##name: \
return "kExpr" #name;
FOREACH_OPCODE(DECLARE_NAME_CASE)
#undef DECLARE_NAME_CASE
default:
break;
}
return "Unknown";
}
} // namespace
bool PrintRawWasmCode(AccountingAllocator* allocator, const FunctionBody& body,
const wasm::WasmModule* module) {
OFStream os(stdout);
Zone zone(allocator, ZONE_NAME);
WasmFullDecoder decoder(&zone, module, body);
int line_nr = 0;
// Print the function signature.
if (body.sig) {
os << "// signature: " << *body.sig << std::endl;
++line_nr;
}
// Print the local declarations.
BodyLocalDecls decls(&zone);
BytecodeIterator i(body.start, body.end, &decls);
if (body.start != i.pc() && !FLAG_wasm_code_fuzzer_gen_test) {
os << "// locals: ";
if (!decls.type_list.empty()) {
ValueType type = decls.type_list[0];
uint32_t count = 0;
for (size_t pos = 0; pos < decls.type_list.size(); ++pos) {
if (decls.type_list[pos] == type) {
++count;
} else {
os << " " << count << " " << WasmOpcodes::TypeName(type);
type = decls.type_list[pos];
count = 1;
}
}
}
os << std::endl;
++line_nr;
for (const byte* locals = body.start; locals < i.pc(); locals++) {
os << (locals == body.start ? "0x" : " 0x") << AsHex(*locals, 2) << ",";
}
os << std::endl;
++line_nr;
}
os << "// body: " << std::endl;
++line_nr;
unsigned control_depth = 0;
for (; i.has_next(); i.next()) {
unsigned length = WasmDecoder::OpcodeLength(&decoder, i.pc());
WasmOpcode opcode = i.current();
if (opcode == kExprElse) control_depth--;
int num_whitespaces = control_depth < 32 ? 2 * control_depth : 64;
// 64 whitespaces
const char* padding =
" ";
os.write(padding, num_whitespaces);
os << RawOpcodeName(opcode) << ",";
for (size_t j = 1; j < length; ++j) {
os << " 0x" << AsHex(i.pc()[j], 2) << ",";
}
switch (opcode) {
case kExprElse:
os << " // @" << i.pc_offset();
control_depth++;
break;
case kExprLoop:
case kExprIf:
case kExprBlock:
case kExprTry: {
BlockTypeOperand operand(&i, i.pc());
os << " // @" << i.pc_offset();
for (unsigned i = 0; i < operand.arity; i++) {
os << " " << WasmOpcodes::TypeName(operand.read_entry(i));
}
control_depth++;
break;
}
case kExprEnd:
os << " // @" << i.pc_offset();
control_depth--;
break;
case kExprBr: {
BreakDepthOperand operand(&i, i.pc());
os << " // depth=" << operand.depth;
break;
}
case kExprBrIf: {
BreakDepthOperand operand(&i, i.pc());
os << " // depth=" << operand.depth;
break;
}
case kExprBrTable: {
BranchTableOperand operand(&i, i.pc());
os << " // entries=" << operand.table_count;
break;
}
case kExprCallIndirect: {
CallIndirectOperand operand(&i, i.pc());
os << " // sig #" << operand.index;
if (decoder.Complete(i.pc(), operand)) {
os << ": " << *operand.sig;
}
break;
}
case kExprCallFunction: {
CallFunctionOperand operand(&i, i.pc());
os << " // function #" << operand.index;
if (decoder.Complete(i.pc(), operand)) {
os << ": " << *operand.sig;
}
break;
}
default:
break;
}
os << std::endl;
++line_nr;
}
return decoder.ok();
}
BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone, size_t num_locals,
const byte* start, const byte* end) {
Decoder decoder(start, end);
return WasmDecoder::AnalyzeLoopAssignment(&decoder, start,
static_cast<int>(num_locals), zone);
}
} // namespace wasm
} // namespace internal
} // namespace v8