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776d6e9d5c
v8/src/wasm/wasm-interpreter.cc
Andreas Rossberg 776d6e9d5c [wasm] Int64 lowering for return values 
R=titzer@chromium.org

Change-Id: Ie8c361efb48b56dc65719f09dfc79d505e0f3459
Reviewed-on: https://chromium-review.googlesource.com/735610
Commit-Queue: Andreas Rossberg <rossberg@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49000}
2017-10-27 11:34:14 +00:00

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// Copyright 2016 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 <type_traits>
#include "src/wasm/wasm-interpreter.h"
#include "src/assembler-inl.h"
#include "src/boxed-float.h"
#include "src/compiler/wasm-compiler.h"
#include "src/conversions.h"
#include "src/identity-map.h"
#include "src/objects-inl.h"
#include "src/utils.h"
#include "src/wasm/decoder.h"
#include "src/wasm/function-body-decoder-impl.h"
#include "src/wasm/function-body-decoder.h"
#include "src/wasm/memory-tracing.h"
#include "src/wasm/wasm-external-refs.h"
#include "src/wasm/wasm-limits.h"
#include "src/wasm/wasm-module.h"
#include "src/wasm/wasm-objects-inl.h"
#include "src/zone/accounting-allocator.h"
#include "src/zone/zone-containers.h"
namespace v8 {
namespace internal {
namespace wasm {
#if DEBUG
#define TRACE(...) \
do { \
if (FLAG_trace_wasm_interpreter) PrintF(__VA_ARGS__); \
} while (false)
#else
#define TRACE(...)
#endif
#define FOREACH_INTERNAL_OPCODE(V) V(Breakpoint, 0xFF)
#define WASM_CTYPES(V) \
V(I32, int32_t) V(I64, int64_t) V(F32, float) V(F64, double)
#define FOREACH_SIMPLE_BINOP(V) \
V(I32Add, uint32_t, +) \
V(I32Sub, uint32_t, -) \
V(I32Mul, uint32_t, *) \
V(I32And, uint32_t, &) \
V(I32Ior, uint32_t, |) \
V(I32Xor, uint32_t, ^) \
V(I32Eq, uint32_t, ==) \
V(I32Ne, uint32_t, !=) \
V(I32LtU, uint32_t, <) \
V(I32LeU, uint32_t, <=) \
V(I32GtU, uint32_t, >) \
V(I32GeU, uint32_t, >=) \
V(I32LtS, int32_t, <) \
V(I32LeS, int32_t, <=) \
V(I32GtS, int32_t, >) \
V(I32GeS, int32_t, >=) \
V(I64Add, uint64_t, +) \
V(I64Sub, uint64_t, -) \
V(I64Mul, uint64_t, *) \
V(I64And, uint64_t, &) \
V(I64Ior, uint64_t, |) \
V(I64Xor, uint64_t, ^) \
V(I64Eq, uint64_t, ==) \
V(I64Ne, uint64_t, !=) \
V(I64LtU, uint64_t, <) \
V(I64LeU, uint64_t, <=) \
V(I64GtU, uint64_t, >) \
V(I64GeU, uint64_t, >=) \
V(I64LtS, int64_t, <) \
V(I64LeS, int64_t, <=) \
V(I64GtS, int64_t, >) \
V(I64GeS, int64_t, >=) \
V(F32Add, float, +) \
V(F32Sub, float, -) \
V(F32Eq, float, ==) \
V(F32Ne, float, !=) \
V(F32Lt, float, <) \
V(F32Le, float, <=) \
V(F32Gt, float, >) \
V(F32Ge, float, >=) \
V(F64Add, double, +) \
V(F64Sub, double, -) \
V(F64Eq, double, ==) \
V(F64Ne, double, !=) \
V(F64Lt, double, <) \
V(F64Le, double, <=) \
V(F64Gt, double, >) \
V(F64Ge, double, >=) \
V(F32Mul, float, *) \
V(F64Mul, double, *) \
V(F32Div, float, /) \
V(F64Div, double, /)
#define FOREACH_OTHER_BINOP(V) \
V(I32DivS, int32_t) \
V(I32DivU, uint32_t) \
V(I32RemS, int32_t) \
V(I32RemU, uint32_t) \
V(I32Shl, uint32_t) \
V(I32ShrU, uint32_t) \
V(I32ShrS, int32_t) \
V(I64DivS, int64_t) \
V(I64DivU, uint64_t) \
V(I64RemS, int64_t) \
V(I64RemU, uint64_t) \
V(I64Shl, uint64_t) \
V(I64ShrU, uint64_t) \
V(I64ShrS, int64_t) \
V(I32Ror, int32_t) \
V(I32Rol, int32_t) \
V(I64Ror, int64_t) \
V(I64Rol, int64_t) \
V(F32Min, float) \
V(F32Max, float) \
V(F64Min, double) \
V(F64Max, double) \
V(I32AsmjsDivS, int32_t) \
V(I32AsmjsDivU, uint32_t) \
V(I32AsmjsRemS, int32_t) \
V(I32AsmjsRemU, uint32_t) \
V(F32CopySign, Float32) \
V(F64CopySign, Float64)
#define FOREACH_OTHER_UNOP(V) \
V(I32Clz, uint32_t) \
V(I32Ctz, uint32_t) \
V(I32Popcnt, uint32_t) \
V(I32Eqz, uint32_t) \
V(I64Clz, uint64_t) \
V(I64Ctz, uint64_t) \
V(I64Popcnt, uint64_t) \
V(I64Eqz, uint64_t) \
V(F32Abs, Float32) \
V(F32Neg, Float32) \
V(F32Ceil, float) \
V(F32Floor, float) \
V(F32Trunc, float) \
V(F32NearestInt, float) \
V(F64Abs, Float64) \
V(F64Neg, Float64) \
V(F64Ceil, double) \
V(F64Floor, double) \
V(F64Trunc, double) \
V(F64NearestInt, double) \
V(I32SConvertF32, float) \
V(I32SConvertF64, double) \
V(I32UConvertF32, float) \
V(I32UConvertF64, double) \
V(I32ConvertI64, int64_t) \
V(I64SConvertF32, float) \
V(I64SConvertF64, double) \
V(I64UConvertF32, float) \
V(I64UConvertF64, double) \
V(I64SConvertI32, int32_t) \
V(I64UConvertI32, uint32_t) \
V(F32SConvertI32, int32_t) \
V(F32UConvertI32, uint32_t) \
V(F32SConvertI64, int64_t) \
V(F32UConvertI64, uint64_t) \
V(F32ConvertF64, double) \
V(F32ReinterpretI32, int32_t) \
V(F64SConvertI32, int32_t) \
V(F64UConvertI32, uint32_t) \
V(F64SConvertI64, int64_t) \
V(F64UConvertI64, uint64_t) \
V(F64ConvertF32, float) \
V(F64ReinterpretI64, int64_t) \
V(I32AsmjsSConvertF32, float) \
V(I32AsmjsUConvertF32, float) \
V(I32AsmjsSConvertF64, double) \
V(I32AsmjsUConvertF64, double) \
V(F32Sqrt, float) \
V(F64Sqrt, double)
namespace {
constexpr uint32_t kFloat32SignBitMask = uint32_t{1} << 31;
constexpr uint64_t kFloat64SignBitMask = uint64_t{1} << 63;
inline int32_t ExecuteI32DivS(int32_t a, int32_t b, TrapReason* trap) {
if (b == 0) {
*trap = kTrapDivByZero;
return 0;
}
if (b == -1 && a == std::numeric_limits<int32_t>::min()) {
*trap = kTrapDivUnrepresentable;
return 0;
}
return a / b;
}
inline uint32_t ExecuteI32DivU(uint32_t a, uint32_t b, TrapReason* trap) {
if (b == 0) {
*trap = kTrapDivByZero;
return 0;
}
return a / b;
}
inline int32_t ExecuteI32RemS(int32_t a, int32_t b, TrapReason* trap) {
if (b == 0) {
*trap = kTrapRemByZero;
return 0;
}
if (b == -1) return 0;
return a % b;
}
inline uint32_t ExecuteI32RemU(uint32_t a, uint32_t b, TrapReason* trap) {
if (b == 0) {
*trap = kTrapRemByZero;
return 0;
}
return a % b;
}
inline uint32_t ExecuteI32Shl(uint32_t a, uint32_t b, TrapReason* trap) {
return a << (b & 0x1f);
}
inline uint32_t ExecuteI32ShrU(uint32_t a, uint32_t b, TrapReason* trap) {
return a >> (b & 0x1f);
}
inline int32_t ExecuteI32ShrS(int32_t a, int32_t b, TrapReason* trap) {
return a >> (b & 0x1f);
}
inline int64_t ExecuteI64DivS(int64_t a, int64_t b, TrapReason* trap) {
if (b == 0) {
*trap = kTrapDivByZero;
return 0;
}
if (b == -1 && a == std::numeric_limits<int64_t>::min()) {
*trap = kTrapDivUnrepresentable;
return 0;
}
return a / b;
}
inline uint64_t ExecuteI64DivU(uint64_t a, uint64_t b, TrapReason* trap) {
if (b == 0) {
*trap = kTrapDivByZero;
return 0;
}
return a / b;
}
inline int64_t ExecuteI64RemS(int64_t a, int64_t b, TrapReason* trap) {
if (b == 0) {
*trap = kTrapRemByZero;
return 0;
}
if (b == -1) return 0;
return a % b;
}
inline uint64_t ExecuteI64RemU(uint64_t a, uint64_t b, TrapReason* trap) {
if (b == 0) {
*trap = kTrapRemByZero;
return 0;
}
return a % b;
}
inline uint64_t ExecuteI64Shl(uint64_t a, uint64_t b, TrapReason* trap) {
return a << (b & 0x3f);
}
inline uint64_t ExecuteI64ShrU(uint64_t a, uint64_t b, TrapReason* trap) {
return a >> (b & 0x3f);
}
inline int64_t ExecuteI64ShrS(int64_t a, int64_t b, TrapReason* trap) {
return a >> (b & 0x3f);
}
inline uint32_t ExecuteI32Ror(uint32_t a, uint32_t b, TrapReason* trap) {
uint32_t shift = (b & 0x1f);
return (a >> shift) | (a << (32 - shift));
}
inline uint32_t ExecuteI32Rol(uint32_t a, uint32_t b, TrapReason* trap) {
uint32_t shift = (b & 0x1f);
return (a << shift) | (a >> (32 - shift));
}
inline uint64_t ExecuteI64Ror(uint64_t a, uint64_t b, TrapReason* trap) {
uint32_t shift = (b & 0x3f);
return (a >> shift) | (a << (64 - shift));
}
inline uint64_t ExecuteI64Rol(uint64_t a, uint64_t b, TrapReason* trap) {
uint32_t shift = (b & 0x3f);
return (a << shift) | (a >> (64 - shift));
}
inline float ExecuteF32Min(float a, float b, TrapReason* trap) {
return JSMin(a, b);
}
inline float ExecuteF32Max(float a, float b, TrapReason* trap) {
return JSMax(a, b);
}
inline Float32 ExecuteF32CopySign(Float32 a, Float32 b, TrapReason* trap) {
return Float32::FromBits((a.get_bits() & ~kFloat32SignBitMask) |
(b.get_bits() & kFloat32SignBitMask));
}
inline double ExecuteF64Min(double a, double b, TrapReason* trap) {
return JSMin(a, b);
}
inline double ExecuteF64Max(double a, double b, TrapReason* trap) {
return JSMax(a, b);
}
inline Float64 ExecuteF64CopySign(Float64 a, Float64 b, TrapReason* trap) {
return Float64::FromBits((a.get_bits() & ~kFloat64SignBitMask) |
(b.get_bits() & kFloat64SignBitMask));
}
inline int32_t ExecuteI32AsmjsDivS(int32_t a, int32_t b, TrapReason* trap) {
if (b == 0) return 0;
if (b == -1 && a == std::numeric_limits<int32_t>::min()) {
return std::numeric_limits<int32_t>::min();
}
return a / b;
}
inline uint32_t ExecuteI32AsmjsDivU(uint32_t a, uint32_t b, TrapReason* trap) {
if (b == 0) return 0;
return a / b;
}
inline int32_t ExecuteI32AsmjsRemS(int32_t a, int32_t b, TrapReason* trap) {
if (b == 0) return 0;
if (b == -1) return 0;
return a % b;
}
inline uint32_t ExecuteI32AsmjsRemU(uint32_t a, uint32_t b, TrapReason* trap) {
if (b == 0) return 0;
return a % b;
}
inline int32_t ExecuteI32AsmjsSConvertF32(float a, TrapReason* trap) {
return DoubleToInt32(a);
}
inline uint32_t ExecuteI32AsmjsUConvertF32(float a, TrapReason* trap) {
return DoubleToUint32(a);
}
inline int32_t ExecuteI32AsmjsSConvertF64(double a, TrapReason* trap) {
return DoubleToInt32(a);
}
inline uint32_t ExecuteI32AsmjsUConvertF64(double a, TrapReason* trap) {
return DoubleToUint32(a);
}
int32_t ExecuteI32Clz(uint32_t val, TrapReason* trap) {
return base::bits::CountLeadingZeros32(val);
}
uint32_t ExecuteI32Ctz(uint32_t val, TrapReason* trap) {
return base::bits::CountTrailingZeros32(val);
}
uint32_t ExecuteI32Popcnt(uint32_t val, TrapReason* trap) {
return word32_popcnt_wrapper(&val);
}
inline uint32_t ExecuteI32Eqz(uint32_t val, TrapReason* trap) {
return val == 0 ? 1 : 0;
}
int64_t ExecuteI64Clz(uint64_t val, TrapReason* trap) {
return base::bits::CountLeadingZeros64(val);
}
inline uint64_t ExecuteI64Ctz(uint64_t val, TrapReason* trap) {
return base::bits::CountTrailingZeros64(val);
}
inline int64_t ExecuteI64Popcnt(uint64_t val, TrapReason* trap) {
return word64_popcnt_wrapper(&val);
}
inline int32_t ExecuteI64Eqz(uint64_t val, TrapReason* trap) {
return val == 0 ? 1 : 0;
}
inline Float32 ExecuteF32Abs(Float32 a, TrapReason* trap) {
return Float32::FromBits(a.get_bits() & ~kFloat32SignBitMask);
}
inline Float32 ExecuteF32Neg(Float32 a, TrapReason* trap) {
return Float32::FromBits(a.get_bits() ^ kFloat32SignBitMask);
}
inline float ExecuteF32Ceil(float a, TrapReason* trap) { return ceilf(a); }
inline float ExecuteF32Floor(float a, TrapReason* trap) { return floorf(a); }
inline float ExecuteF32Trunc(float a, TrapReason* trap) { return truncf(a); }
inline float ExecuteF32NearestInt(float a, TrapReason* trap) {
return nearbyintf(a);
}
inline float ExecuteF32Sqrt(float a, TrapReason* trap) {
float result = sqrtf(a);
return result;
}
inline Float64 ExecuteF64Abs(Float64 a, TrapReason* trap) {
return Float64::FromBits(a.get_bits() & ~kFloat64SignBitMask);
}
inline Float64 ExecuteF64Neg(Float64 a, TrapReason* trap) {
return Float64::FromBits(a.get_bits() ^ kFloat64SignBitMask);
}
inline double ExecuteF64Ceil(double a, TrapReason* trap) { return ceil(a); }
inline double ExecuteF64Floor(double a, TrapReason* trap) { return floor(a); }
inline double ExecuteF64Trunc(double a, TrapReason* trap) { return trunc(a); }
inline double ExecuteF64NearestInt(double a, TrapReason* trap) {
return nearbyint(a);
}
inline double ExecuteF64Sqrt(double a, TrapReason* trap) { return sqrt(a); }
int32_t ExecuteI32SConvertF32(float a, TrapReason* trap) {
// The upper bound is (INT32_MAX + 1), which is the lowest float-representable
// number above INT32_MAX which cannot be represented as int32.
float upper_bound = 2147483648.0f;
// We use INT32_MIN as a lower bound because (INT32_MIN - 1) is not
// representable as float, and no number between (INT32_MIN - 1) and INT32_MIN
// is.
float lower_bound = static_cast<float>(INT32_MIN);
if (a < upper_bound && a >= lower_bound) {
return static_cast<int32_t>(a);
}
*trap = kTrapFloatUnrepresentable;
return 0;
}
int32_t ExecuteI32SConvertF64(double a, TrapReason* trap) {
// The upper bound is (INT32_MAX + 1), which is the lowest double-
// representable number above INT32_MAX which cannot be represented as int32.
double upper_bound = 2147483648.0;
// The lower bound is (INT32_MIN - 1), which is the greatest double-
// representable number below INT32_MIN which cannot be represented as int32.
double lower_bound = -2147483649.0;
if (a < upper_bound && a > lower_bound) {
return static_cast<int32_t>(a);
}
*trap = kTrapFloatUnrepresentable;
return 0;
}
uint32_t ExecuteI32UConvertF32(float a, TrapReason* trap) {
// The upper bound is (UINT32_MAX + 1), which is the lowest
// float-representable number above UINT32_MAX which cannot be represented as
// uint32.
double upper_bound = 4294967296.0f;
double lower_bound = -1.0f;
if (a < upper_bound && a > lower_bound) {
return static_cast<uint32_t>(a);
}
*trap = kTrapFloatUnrepresentable;
return 0;
}
uint32_t ExecuteI32UConvertF64(double a, TrapReason* trap) {
// The upper bound is (UINT32_MAX + 1), which is the lowest
// double-representable number above UINT32_MAX which cannot be represented as
// uint32.
double upper_bound = 4294967296.0;
double lower_bound = -1.0;
if (a < upper_bound && a > lower_bound) {
return static_cast<uint32_t>(a);
}
*trap = kTrapFloatUnrepresentable;
return 0;
}
inline uint32_t ExecuteI32ConvertI64(int64_t a, TrapReason* trap) {
return static_cast<uint32_t>(a & 0xFFFFFFFF);
}
int64_t ExecuteI64SConvertF32(float a, TrapReason* trap) {
int64_t output;
if (!float32_to_int64_wrapper(&a, &output)) {
*trap = kTrapFloatUnrepresentable;
}
return output;
}
int64_t ExecuteI64SConvertF64(double a, TrapReason* trap) {
int64_t output;
if (!float64_to_int64_wrapper(&a, &output)) {
*trap = kTrapFloatUnrepresentable;
}
return output;
}
uint64_t ExecuteI64UConvertF32(float a, TrapReason* trap) {
uint64_t output;
if (!float32_to_uint64_wrapper(&a, &output)) {
*trap = kTrapFloatUnrepresentable;
}
return output;
}
uint64_t ExecuteI64UConvertF64(double a, TrapReason* trap) {
uint64_t output;
if (!float64_to_uint64_wrapper(&a, &output)) {
*trap = kTrapFloatUnrepresentable;
}
return output;
}
inline int64_t ExecuteI64SConvertI32(int32_t a, TrapReason* trap) {
return static_cast<int64_t>(a);
}
inline int64_t ExecuteI64UConvertI32(uint32_t a, TrapReason* trap) {
return static_cast<uint64_t>(a);
}
inline float ExecuteF32SConvertI32(int32_t a, TrapReason* trap) {
return static_cast<float>(a);
}
inline float ExecuteF32UConvertI32(uint32_t a, TrapReason* trap) {
return static_cast<float>(a);
}
inline float ExecuteF32SConvertI64(int64_t a, TrapReason* trap) {
float output;
int64_to_float32_wrapper(&a, &output);
return output;
}
inline float ExecuteF32UConvertI64(uint64_t a, TrapReason* trap) {
float output;
uint64_to_float32_wrapper(&a, &output);
return output;
}
inline float ExecuteF32ConvertF64(double a, TrapReason* trap) {
return static_cast<float>(a);
}
inline Float32 ExecuteF32ReinterpretI32(int32_t a, TrapReason* trap) {
return Float32::FromBits(a);
}
inline double ExecuteF64SConvertI32(int32_t a, TrapReason* trap) {
return static_cast<double>(a);
}
inline double ExecuteF64UConvertI32(uint32_t a, TrapReason* trap) {
return static_cast<double>(a);
}
inline double ExecuteF64SConvertI64(int64_t a, TrapReason* trap) {
double output;
int64_to_float64_wrapper(&a, &output);
return output;
}
inline double ExecuteF64UConvertI64(uint64_t a, TrapReason* trap) {
double output;
uint64_to_float64_wrapper(&a, &output);
return output;
}
inline double ExecuteF64ConvertF32(float a, TrapReason* trap) {
return static_cast<double>(a);
}
inline Float64 ExecuteF64ReinterpretI64(int64_t a, TrapReason* trap) {
return Float64::FromBits(a);
}
inline int32_t ExecuteI32ReinterpretF32(WasmValue a) {
return a.to_f32_boxed().get_bits();
}
inline int64_t ExecuteI64ReinterpretF64(WasmValue a) {
return a.to_f64_boxed().get_bits();
}
enum InternalOpcode {
#define DECL_INTERNAL_ENUM(name, value) kInternal##name = value,
FOREACH_INTERNAL_OPCODE(DECL_INTERNAL_ENUM)
#undef DECL_INTERNAL_ENUM
};
const char* OpcodeName(uint32_t val) {
switch (val) {
#define DECL_INTERNAL_CASE(name, value) \
case kInternal##name: \
return "Internal" #name;
FOREACH_INTERNAL_OPCODE(DECL_INTERNAL_CASE)
#undef DECL_INTERNAL_CASE
}
return WasmOpcodes::OpcodeName(static_cast<WasmOpcode>(val));
}
// Unwrap a wasm to js wrapper, return the callable heap object.
// If the wrapper would throw a TypeError, return a null handle.
Handle<HeapObject> UnwrapWasmToJSWrapper(Isolate* isolate,
Handle<Code> js_wrapper) {
DCHECK_EQ(Code::WASM_TO_JS_FUNCTION, js_wrapper->kind());
Handle<FixedArray> deopt_data(js_wrapper->deoptimization_data(), isolate);
DCHECK_EQ(2, deopt_data->length());
intptr_t js_imports_table_loc = static_cast<intptr_t>(
HeapNumber::cast(deopt_data->get(0))->value_as_bits());
Handle<FixedArray> js_imports_table(
reinterpret_cast<FixedArray**>(js_imports_table_loc));
int index = 0;
CHECK(deopt_data->get(1)->ToInt32(&index));
DCHECK_GT(js_imports_table->length(), index);
Handle<Object> obj(js_imports_table->get(index), isolate);
if (obj->IsCallable()) {
return Handle<HeapObject>::cast(obj);
} else {
// If we did not find a callable object, this is an illegal JS import and
// obj must be undefined.
DCHECK(obj->IsUndefined(isolate));
return Handle<HeapObject>::null();
}
}
class SideTable;
// Code and metadata needed to execute a function.
struct InterpreterCode {
const WasmFunction* function; // wasm function
BodyLocalDecls locals; // local declarations
const byte* orig_start; // start of original code
const byte* orig_end; // end of original code
byte* start; // start of (maybe altered) code
byte* end; // end of (maybe altered) code
SideTable* side_table; // precomputed side table for control flow.
const byte* at(pc_t pc) { return start + pc; }
};
// A helper class to compute the control transfers for each bytecode offset.
// Control transfers allow Br, BrIf, BrTable, If, Else, and End bytecodes to
// be directly executed without the need to dynamically track blocks.
class SideTable : public ZoneObject {
public:
ControlTransferMap map_;
uint32_t max_stack_height_;
SideTable(Zone* zone, const WasmModule* module, InterpreterCode* code)
: map_(zone), max_stack_height_(0) {
// Create a zone for all temporary objects.
Zone control_transfer_zone(zone->allocator(), ZONE_NAME);
// Represents a control flow label.
class CLabel : public ZoneObject {
explicit CLabel(Zone* zone, uint32_t target_stack_height, uint32_t arity)
: target(nullptr),
target_stack_height(target_stack_height),
arity(arity),
refs(zone) {}
public:
struct Ref {
const byte* from_pc;
const uint32_t stack_height;
};
const byte* target;
uint32_t target_stack_height;
// Arity when branching to this label.
const uint32_t arity;
ZoneVector<Ref> refs;
static CLabel* New(Zone* zone, uint32_t stack_height, uint32_t arity) {
return new (zone) CLabel(zone, stack_height, arity);
}
// Bind this label to the given PC.
void Bind(const byte* pc) {
DCHECK_NULL(target);
target = pc;
}
// Reference this label from the given location.
void Ref(const byte* from_pc, uint32_t stack_height) {
// Target being bound before a reference means this is a loop.
DCHECK_IMPLIES(target, *target == kExprLoop);
refs.push_back({from_pc, stack_height});
}
void Finish(ControlTransferMap* map, const byte* start) {
DCHECK_NOT_NULL(target);
for (auto ref : refs) {
size_t offset = static_cast<size_t>(ref.from_pc - start);
auto pcdiff = static_cast<pcdiff_t>(target - ref.from_pc);
DCHECK_GE(ref.stack_height, target_stack_height);
spdiff_t spdiff =
static_cast<spdiff_t>(ref.stack_height - target_stack_height);
TRACE("control transfer @%zu: Δpc %d, stack %u->%u = -%u\n", offset,
pcdiff, ref.stack_height, target_stack_height, spdiff);
ControlTransferEntry& entry = (*map)[offset];
entry.pc_diff = pcdiff;
entry.sp_diff = spdiff;
entry.target_arity = arity;
}
}
};
// An entry in the control stack.
struct Control {
const byte* pc;
CLabel* end_label;
CLabel* else_label;
// Arity (number of values on the stack) when exiting this control
// structure via |end|.
uint32_t exit_arity;
// Track whether this block was already left, i.e. all further
// instructions are unreachable.
bool unreachable = false;
Control(const byte* pc, CLabel* end_label, CLabel* else_label,
uint32_t exit_arity)
: pc(pc),
end_label(end_label),
else_label(else_label),
exit_arity(exit_arity) {}
Control(const byte* pc, CLabel* end_label, uint32_t exit_arity)
: Control(pc, end_label, nullptr, exit_arity) {}
void Finish(ControlTransferMap* map, const byte* start) {
end_label->Finish(map, start);
if (else_label) else_label->Finish(map, start);
}
};
// Compute the ControlTransfer map.
// This algorithm maintains a stack of control constructs similar to the
// AST decoder. The {control_stack} allows matching {br,br_if,br_table}
// bytecodes with their target, as well as determining whether the current
// bytecodes are within the true or false block of an else.
ZoneVector<Control> control_stack(&control_transfer_zone);
uint32_t stack_height = 0;
uint32_t func_arity =
static_cast<uint32_t>(code->function->sig->return_count());
CLabel* func_label =
CLabel::New(&control_transfer_zone, stack_height, func_arity);
control_stack.emplace_back(code->orig_start, func_label, func_arity);
auto control_parent = [&]() -> Control& {
DCHECK_LE(2, control_stack.size());
return control_stack[control_stack.size() - 2];
};
auto copy_unreachable = [&] {
control_stack.back().unreachable = control_parent().unreachable;
};
for (BytecodeIterator i(code->orig_start, code->orig_end, &code->locals);
i.has_next(); i.next()) {
WasmOpcode opcode = i.current();
bool unreachable = control_stack.back().unreachable;
if (unreachable) {
TRACE("@%u: %s (is unreachable)\n", i.pc_offset(),
WasmOpcodes::OpcodeName(opcode));
} else {
auto stack_effect =
StackEffect(module, code->function->sig, i.pc(), i.end());
TRACE("@%u: %s (sp %d - %d + %d)\n", i.pc_offset(),
WasmOpcodes::OpcodeName(opcode), stack_height, stack_effect.first,
stack_effect.second);
DCHECK_GE(stack_height, stack_effect.first);
DCHECK_GE(kMaxUInt32, static_cast<uint64_t>(stack_height) -
stack_effect.first + stack_effect.second);
stack_height = stack_height - stack_effect.first + stack_effect.second;
if (stack_height > max_stack_height_) max_stack_height_ = stack_height;
}
switch (opcode) {
case kExprBlock:
case kExprLoop: {
bool is_loop = opcode == kExprLoop;
BlockTypeOperand<Decoder::kNoValidate> operand(&i, i.pc());
if (operand.type == kWasmVar) {
operand.sig = module->signatures[operand.sig_index];
}
TRACE("control @%u: %s, arity %d->%d\n", i.pc_offset(),
is_loop ? "Loop" : "Block",
operand.in_arity(), operand.out_arity());
CLabel* label = CLabel::New(&control_transfer_zone, stack_height,
is_loop ? operand.in_arity()
: operand.out_arity());
control_stack.emplace_back(i.pc(), label, operand.out_arity());
copy_unreachable();
if (is_loop) label->Bind(i.pc());
break;
}
case kExprIf: {
BlockTypeOperand<Decoder::kNoValidate> operand(&i, i.pc());
if (operand.type == kWasmVar) {
operand.sig = module->signatures[operand.sig_index];
}
TRACE("control @%u: If, arity %d->%d\n", i.pc_offset(),
operand.in_arity(), operand.out_arity());
CLabel* end_label =
CLabel::New(&control_transfer_zone, stack_height,
operand.out_arity());
CLabel* else_label =
CLabel::New(&control_transfer_zone, stack_height, 0);
control_stack.emplace_back(i.pc(), end_label, else_label,
operand.out_arity());
copy_unreachable();
if (!unreachable) else_label->Ref(i.pc(), stack_height);
break;
}
case kExprElse: {
Control* c = &control_stack.back();
copy_unreachable();
TRACE("control @%u: Else\n", i.pc_offset());
if (!control_parent().unreachable) {
c->end_label->Ref(i.pc(), stack_height);
}
DCHECK_NOT_NULL(c->else_label);
c->else_label->Bind(i.pc() + 1);
c->else_label->Finish(&map_, code->orig_start);
c->else_label = nullptr;
DCHECK_GE(stack_height, c->end_label->target_stack_height);
stack_height = c->end_label->target_stack_height;
break;
}
case kExprEnd: {
Control* c = &control_stack.back();
TRACE("control @%u: End\n", i.pc_offset());
// Only loops have bound labels.
DCHECK_IMPLIES(c->end_label->target, *c->pc == kExprLoop);
if (!c->end_label->target) {
if (c->else_label) c->else_label->Bind(i.pc());
c->end_label->Bind(i.pc() + 1);
}
c->Finish(&map_, code->orig_start);
DCHECK_GE(stack_height, c->end_label->target_stack_height);
stack_height = c->end_label->target_stack_height + c->exit_arity;
control_stack.pop_back();
break;
}
case kExprBr: {
BreakDepthOperand<Decoder::kNoValidate> operand(&i, i.pc());
TRACE("control @%u: Br[depth=%u]\n", i.pc_offset(), operand.depth);
Control* c = &control_stack[control_stack.size() - operand.depth - 1];
if (!unreachable) c->end_label->Ref(i.pc(), stack_height);
break;
}
case kExprBrIf: {
BreakDepthOperand<Decoder::kNoValidate> operand(&i, i.pc());
TRACE("control @%u: BrIf[depth=%u]\n", i.pc_offset(), operand.depth);
Control* c = &control_stack[control_stack.size() - operand.depth - 1];
if (!unreachable) c->end_label->Ref(i.pc(), stack_height);
break;
}
case kExprBrTable: {
BranchTableOperand<Decoder::kNoValidate> operand(&i, i.pc());
BranchTableIterator<Decoder::kNoValidate> iterator(&i, operand);
TRACE("control @%u: BrTable[count=%u]\n", i.pc_offset(),
operand.table_count);
if (!unreachable) {
while (iterator.has_next()) {
uint32_t j = iterator.cur_index();
uint32_t target = iterator.next();
Control* c = &control_stack[control_stack.size() - target - 1];
c->end_label->Ref(i.pc() + j, stack_height);
}
}
break;
}
default:
break;
}
if (WasmOpcodes::IsUnconditionalJump(opcode)) {
control_stack.back().unreachable = true;
}
}
DCHECK_EQ(0, control_stack.size());
DCHECK_EQ(func_arity, stack_height);
}
ControlTransferEntry& Lookup(pc_t from) {
auto result = map_.find(from);
DCHECK(result != map_.end());
return result->second;
}
};
struct ExternalCallResult {
enum Type {
// The function should be executed inside this interpreter.
INTERNAL,
// For indirect calls: Table or function does not exist.
INVALID_FUNC,
// For indirect calls: Signature does not match expected signature.
SIGNATURE_MISMATCH,
// The function was executed and returned normally.
EXTERNAL_RETURNED,
// The function was executed, threw an exception, and the stack was unwound.
EXTERNAL_UNWOUND
};
Type type;
// If type is INTERNAL, this field holds the function to call internally.
InterpreterCode* interpreter_code;
ExternalCallResult(Type type) : type(type) { // NOLINT
DCHECK_NE(INTERNAL, type);
}
ExternalCallResult(Type type, InterpreterCode* code)
: type(type), interpreter_code(code) {
DCHECK_EQ(INTERNAL, type);
}
};
// The main storage for interpreter code. It maps {WasmFunction} to the
// metadata needed to execute each function.
class CodeMap {
Zone* zone_;
const WasmModule* module_;
ZoneVector<InterpreterCode> interpreter_code_;
// This handle is set and reset by the SetInstanceObject() /
// ClearInstanceObject() method, which is used by the HeapObjectsScope.
Handle<WasmInstanceObject> instance_;
public:
CodeMap(Isolate* isolate, const WasmModule* module,
const uint8_t* module_start, Zone* zone)
: zone_(zone), module_(module), interpreter_code_(zone) {
if (module == nullptr) return;
interpreter_code_.reserve(module->functions.size());
for (const WasmFunction& function : module->functions) {
if (function.imported) {
DCHECK(!function.code.is_set());
AddFunction(&function, nullptr, nullptr);
} else {
AddFunction(&function, module_start + function.code.offset(),
module_start + function.code.end_offset());
}
}
}
void SetInstanceObject(Handle<WasmInstanceObject> instance) {
DCHECK(instance_.is_null());
instance_ = instance;
}
void ClearInstanceObject() { instance_ = Handle<WasmInstanceObject>::null(); }
const WasmModule* module() const { return module_; }
bool has_instance() const { return !instance_.is_null(); }
WasmInstanceObject* instance() const {
DCHECK(has_instance());
return *instance_;
}
MaybeHandle<WasmInstanceObject> maybe_instance() const {
return has_instance() ? handle(instance())
: MaybeHandle<WasmInstanceObject>();
}
Code* GetImportedFunction(uint32_t function_index) {
DCHECK(has_instance());
DCHECK_GT(module_->num_imported_functions, function_index);
FixedArray* code_table = instance()->compiled_module()->ptr_to_code_table();
return Code::cast(code_table->get(static_cast<int>(function_index)));
}
InterpreterCode* GetCode(const WasmFunction* function) {
InterpreterCode* code = GetCode(function->func_index);
DCHECK_EQ(function, code->function);
return code;
}
InterpreterCode* GetCode(uint32_t function_index) {
DCHECK_LT(function_index, interpreter_code_.size());
return Preprocess(&interpreter_code_[function_index]);
}
InterpreterCode* GetIndirectCode(uint32_t table_index, uint32_t entry_index) {
if (table_index >= module_->function_tables.size()) return nullptr;
const WasmIndirectFunctionTable* table =
&module_->function_tables[table_index];
if (entry_index >= table->values.size()) return nullptr;
uint32_t index = table->values[entry_index];
if (index >= interpreter_code_.size()) return nullptr;
return GetCode(index);
}
InterpreterCode* Preprocess(InterpreterCode* code) {
DCHECK_EQ(code->function->imported, code->start == nullptr);
if (!code->side_table && code->start) {
// Compute the control targets map and the local declarations.
code->side_table = new (zone_) SideTable(zone_, module_, code);
}
return code;
}
void AddFunction(const WasmFunction* function, const byte* code_start,
const byte* code_end) {
InterpreterCode code = {
function, BodyLocalDecls(zone_), code_start,
code_end, const_cast<byte*>(code_start), const_cast<byte*>(code_end),
nullptr};
DCHECK_EQ(interpreter_code_.size(), function->func_index);
interpreter_code_.push_back(code);
}
void SetFunctionCode(const WasmFunction* function, const byte* start,
const byte* end) {
DCHECK_LT(function->func_index, interpreter_code_.size());
InterpreterCode* code = &interpreter_code_[function->func_index];
DCHECK_EQ(function, code->function);
code->orig_start = start;
code->orig_end = end;
code->start = const_cast<byte*>(start);
code->end = const_cast<byte*>(end);
code->side_table = nullptr;
Preprocess(code);
}
};
Handle<Object> WasmValueToNumber(Factory* factory, WasmValue val,
wasm::ValueType type) {
switch (type) {
case kWasmI32:
return factory->NewNumberFromInt(val.to<int32_t>());
case kWasmI64:
// wasm->js and js->wasm is illegal for i64 type.
UNREACHABLE();
case kWasmF32:
return factory->NewNumber(val.to<float>());
case kWasmF64:
return factory->NewNumber(val.to<double>());
default:
// TODO(wasm): Implement simd.
UNIMPLEMENTED();
return Handle<Object>::null();
}
}
// Convert JS value to WebAssembly, spec here:
// https://github.com/WebAssembly/design/blob/master/JS.md#towebassemblyvalue
// Return WasmValue() (i.e. of type kWasmStmt) on failure. In that case, an
// exception will be pending on the isolate.
WasmValue ToWebAssemblyValue(Isolate* isolate, Handle<Object> value,
wasm::ValueType type) {
switch (type) {
case kWasmI32: {
MaybeHandle<Object> maybe_i32 = Object::ToInt32(isolate, value);
if (maybe_i32.is_null()) return {};
int32_t value;
CHECK(maybe_i32.ToHandleChecked()->ToInt32(&value));
return WasmValue(value);
}
case kWasmI64:
// If the signature contains i64, a type error was thrown before.
UNREACHABLE();
case kWasmF32: {
MaybeHandle<Object> maybe_number = Object::ToNumber(value);
if (maybe_number.is_null()) return {};
return WasmValue(
static_cast<float>(maybe_number.ToHandleChecked()->Number()));
}
case kWasmF64: {
MaybeHandle<Object> maybe_number = Object::ToNumber(value);
if (maybe_number.is_null()) return {};
return WasmValue(maybe_number.ToHandleChecked()->Number());
}
default:
// TODO(wasm): Handle simd.
UNIMPLEMENTED();
return WasmValue();
}
}
// Like a static_cast from src to dst, but specialized for boxed floats.
template <typename dst, typename src>
struct converter {
dst operator()(src val) const { return static_cast<dst>(val); }
};
template <>
struct converter<Float64, uint64_t> {
Float64 operator()(uint64_t val) const { return Float64::FromBits(val); }
};
template <>
struct converter<Float32, uint32_t> {
Float32 operator()(uint32_t val) const { return Float32::FromBits(val); }
};
template <>
struct converter<uint64_t, Float64> {
uint64_t operator()(Float64 val) const { return val.get_bits(); }
};
template <>
struct converter<uint32_t, Float32> {
uint32_t operator()(Float32 val) const { return val.get_bits(); }
};
template <typename T>
V8_INLINE bool has_nondeterminism(T val) {
static_assert(!std::is_floating_point<T>::value, "missing specialization");
return false;
}
template <>
V8_INLINE bool has_nondeterminism<float>(float val) {
return std::isnan(val);
}
template <>
V8_INLINE bool has_nondeterminism<double>(double val) {
return std::isnan(val);
}
// Responsible for executing code directly.
class ThreadImpl {
struct Activation {
uint32_t fp;
sp_t sp;
Activation(uint32_t fp, sp_t sp) : fp(fp), sp(sp) {}
};
public:
ThreadImpl(Zone* zone, CodeMap* codemap, WasmContext* wasm_context)
: codemap_(codemap),
wasm_context_(wasm_context),
zone_(zone),
frames_(zone),
activations_(zone) {}
//==========================================================================
// Implementation of public interface for WasmInterpreter::Thread.
//==========================================================================
WasmInterpreter::State state() { return state_; }
void InitFrame(const WasmFunction* function, WasmValue* args) {
DCHECK_EQ(current_activation().fp, frames_.size());
InterpreterCode* code = codemap()->GetCode(function);
size_t num_params = function->sig->parameter_count();
EnsureStackSpace(num_params);
Push(args, num_params);
PushFrame(code);
}
WasmInterpreter::State Run(int num_steps = -1) {
DCHECK(state_ == WasmInterpreter::STOPPED ||
state_ == WasmInterpreter::PAUSED);
DCHECK(num_steps == -1 || num_steps > 0);
if (num_steps == -1) {
TRACE(" => Run()\n");
} else if (num_steps == 1) {
TRACE(" => Step()\n");
} else {
TRACE(" => Run(%d)\n", num_steps);
}
state_ = WasmInterpreter::RUNNING;
Execute(frames_.back().code, frames_.back().pc, num_steps);
// If state_ is STOPPED, the current activation must be fully unwound.
DCHECK_IMPLIES(state_ == WasmInterpreter::STOPPED,
current_activation().fp == frames_.size());
return state_;
}
void Pause() { UNIMPLEMENTED(); }
void Reset() {
TRACE("----- RESET -----\n");
sp_ = stack_start_;
frames_.clear();
state_ = WasmInterpreter::STOPPED;
trap_reason_ = kTrapCount;
possible_nondeterminism_ = false;
}
int GetFrameCount() {
DCHECK_GE(kMaxInt, frames_.size());
return static_cast<int>(frames_.size());
}
WasmValue GetReturnValue(uint32_t index) {
if (state_ == WasmInterpreter::TRAPPED) return WasmValue(0xdeadbeef);
DCHECK_EQ(WasmInterpreter::FINISHED, state_);
Activation act = current_activation();
// Current activation must be finished.
DCHECK_EQ(act.fp, frames_.size());
return GetStackValue(act.sp + index);
}
WasmValue GetStackValue(sp_t index) {
DCHECK_GT(StackHeight(), index);
return stack_start_[index];
}
void SetStackValue(sp_t index, WasmValue value) {
DCHECK_GT(StackHeight(), index);
stack_start_[index] = value;
}
TrapReason GetTrapReason() { return trap_reason_; }
pc_t GetBreakpointPc() { return break_pc_; }
bool PossibleNondeterminism() { return possible_nondeterminism_; }
uint64_t NumInterpretedCalls() { return num_interpreted_calls_; }
void AddBreakFlags(uint8_t flags) { break_flags_ |= flags; }
void ClearBreakFlags() { break_flags_ = WasmInterpreter::BreakFlag::None; }
uint32_t NumActivations() {
return static_cast<uint32_t>(activations_.size());
}
uint32_t StartActivation() {
TRACE("----- START ACTIVATION %zu -----\n", activations_.size());
// If you use activations, use them consistently:
DCHECK_IMPLIES(activations_.empty(), frames_.empty());
DCHECK_IMPLIES(activations_.empty(), StackHeight() == 0);
uint32_t activation_id = static_cast<uint32_t>(activations_.size());
activations_.emplace_back(static_cast<uint32_t>(frames_.size()),
StackHeight());
state_ = WasmInterpreter::STOPPED;
return activation_id;
}
void FinishActivation(uint32_t id) {
TRACE("----- FINISH ACTIVATION %zu -----\n", activations_.size() - 1);
DCHECK_LT(0, activations_.size());
DCHECK_EQ(activations_.size() - 1, id);
// Stack height must match the start of this activation (otherwise unwind
// first).
DCHECK_EQ(activations_.back().fp, frames_.size());
DCHECK_LE(activations_.back().sp, StackHeight());
sp_ = stack_start_ + activations_.back().sp;
activations_.pop_back();
}
uint32_t ActivationFrameBase(uint32_t id) {
DCHECK_GT(activations_.size(), id);
return activations_[id].fp;
}
// Handle a thrown exception. Returns whether the exception was handled inside
// the current activation. Unwinds the interpreted stack accordingly.
WasmInterpreter::Thread::ExceptionHandlingResult HandleException(
Isolate* isolate) {
DCHECK(isolate->has_pending_exception());
// TODO(wasm): Add wasm exception handling (would return HANDLED).
USE(isolate->pending_exception());
TRACE("----- UNWIND -----\n");
DCHECK_LT(0, activations_.size());
Activation& act = activations_.back();
DCHECK_LE(act.fp, frames_.size());
frames_.resize(act.fp);
DCHECK_LE(act.sp, StackHeight());
sp_ = stack_start_ + act.sp;
state_ = WasmInterpreter::STOPPED;
return WasmInterpreter::Thread::UNWOUND;
}
private:
// Entries on the stack of functions being evaluated.
struct Frame {
InterpreterCode* code;
pc_t pc;
sp_t sp;
// Limit of parameters.
sp_t plimit() { return sp + code->function->sig->parameter_count(); }
// Limit of locals.
sp_t llimit() { return plimit() + code->locals.type_list.size(); }
};
struct Block {
pc_t pc;
sp_t sp;
size_t fp;
unsigned arity;
};
friend class InterpretedFrameImpl;
CodeMap* codemap_;
WasmContext* wasm_context_;
Zone* zone_;
WasmValue* stack_start_ = nullptr; // Start of allocated stack space.
WasmValue* stack_limit_ = nullptr; // End of allocated stack space.
WasmValue* sp_ = nullptr; // Current stack pointer.
ZoneVector<Frame> frames_;
WasmInterpreter::State state_ = WasmInterpreter::STOPPED;
pc_t break_pc_ = kInvalidPc;
TrapReason trap_reason_ = kTrapCount;
bool possible_nondeterminism_ = false;
uint8_t break_flags_ = 0; // a combination of WasmInterpreter::BreakFlag
uint64_t num_interpreted_calls_ = 0;
// Store the stack height of each activation (for unwind and frame
// inspection).
ZoneVector<Activation> activations_;
CodeMap* codemap() const { return codemap_; }
const WasmModule* module() const { return codemap_->module(); }
void DoTrap(TrapReason trap, pc_t pc) {
state_ = WasmInterpreter::TRAPPED;
trap_reason_ = trap;
CommitPc(pc);
}
// Push a frame with arguments already on the stack.
void PushFrame(InterpreterCode* code) {
DCHECK_NOT_NULL(code);
DCHECK_NOT_NULL(code->side_table);
EnsureStackSpace(code->side_table->max_stack_height_ +
code->locals.type_list.size());
++num_interpreted_calls_;
size_t arity = code->function->sig->parameter_count();
// The parameters will overlap the arguments already on the stack.
DCHECK_GE(StackHeight(), arity);
frames_.push_back({code, 0, StackHeight() - arity});
frames_.back().pc = InitLocals(code);
TRACE(" => PushFrame #%zu (#%u @%zu)\n", frames_.size() - 1,
code->function->func_index, frames_.back().pc);
}
pc_t InitLocals(InterpreterCode* code) {
for (auto p : code->locals.type_list) {
WasmValue val;
switch (p) {
#define CASE_TYPE(wasm, ctype) \
case kWasm##wasm: \
val = WasmValue(static_cast<ctype>(0)); \
break;
WASM_CTYPES(CASE_TYPE)
#undef CASE_TYPE
default:
UNREACHABLE();
break;
}
Push(val);
}
return code->locals.encoded_size;
}
void CommitPc(pc_t pc) {
DCHECK(!frames_.empty());
frames_.back().pc = pc;
}
bool SkipBreakpoint(InterpreterCode* code, pc_t pc) {
if (pc == break_pc_) {
// Skip the previously hit breakpoint when resuming.
break_pc_ = kInvalidPc;
return true;
}
return false;
}
int LookupTargetDelta(InterpreterCode* code, pc_t pc) {
return static_cast<int>(code->side_table->Lookup(pc).pc_diff);
}
int DoBreak(InterpreterCode* code, pc_t pc, size_t depth) {
ControlTransferEntry& control_transfer_entry = code->side_table->Lookup(pc);
DoStackTransfer(sp_ - control_transfer_entry.sp_diff,
control_transfer_entry.target_arity);
return control_transfer_entry.pc_diff;
}
pc_t ReturnPc(Decoder* decoder, InterpreterCode* code, pc_t pc) {
switch (code->orig_start[pc]) {
case kExprCallFunction: {
CallFunctionOperand<Decoder::kNoValidate> operand(decoder,
code->at(pc));
return pc + 1 + operand.length;
}
case kExprCallIndirect: {
CallIndirectOperand<Decoder::kNoValidate> operand(decoder,
code->at(pc));
return pc + 1 + operand.length;
}
default:
UNREACHABLE();
}
}
bool DoReturn(Decoder* decoder, InterpreterCode** code, pc_t* pc, pc_t* limit,
size_t arity) {
DCHECK_GT(frames_.size(), 0);
WasmValue* sp_dest = stack_start_ + frames_.back().sp;
frames_.pop_back();
if (frames_.size() == current_activation().fp) {
// A return from the last frame terminates the execution.
state_ = WasmInterpreter::FINISHED;
DoStackTransfer(sp_dest, arity);
TRACE(" => finish\n");
return false;
} else {
// Return to caller frame.
Frame* top = &frames_.back();
*code = top->code;
decoder->Reset((*code)->start, (*code)->end);
*pc = ReturnPc(decoder, *code, top->pc);
*limit = top->code->end - top->code->start;
TRACE(" => Return to #%zu (#%u @%zu)\n", frames_.size() - 1,
(*code)->function->func_index, *pc);
DoStackTransfer(sp_dest, arity);
return true;
}
}
// Returns true if the call was successful, false if the stack check failed
// and the current activation was fully unwound.
bool DoCall(Decoder* decoder, InterpreterCode* target, pc_t* pc,
pc_t* limit) WARN_UNUSED_RESULT {
frames_.back().pc = *pc;
PushFrame(target);
if (!DoStackCheck()) return false;
*pc = frames_.back().pc;
*limit = target->end - target->start;
decoder->Reset(target->start, target->end);
return true;
}
// Copies {arity} values on the top of the stack down the stack to {dest},
// dropping the values in-between.
void DoStackTransfer(WasmValue* dest, size_t arity) {
// before: |---------------| pop_count | arity |
// ^ 0 ^ dest ^ sp_
//
// after: |---------------| arity |
// ^ 0 ^ sp_
DCHECK_LE(dest, sp_);
DCHECK_LE(dest + arity, sp_);
if (arity) memmove(dest, sp_ - arity, arity * sizeof(*sp_));
sp_ = dest + arity;
}
template <typename mtype>
inline bool BoundsCheck(uint32_t mem_size, uint32_t offset, uint32_t index) {
return sizeof(mtype) <= mem_size && offset <= mem_size - sizeof(mtype) &&
index <= mem_size - sizeof(mtype) - offset;
}
template <typename ctype, typename mtype>
bool ExecuteLoad(Decoder* decoder, InterpreterCode* code, pc_t pc, int& len,
MachineRepresentation rep) {
MemoryAccessOperand<Decoder::kNoValidate> operand(decoder, code->at(pc),
sizeof(ctype));
uint32_t index = Pop().to<uint32_t>();
if (!BoundsCheck<mtype>(wasm_context_->mem_size, operand.offset, index)) {
DoTrap(kTrapMemOutOfBounds, pc);
return false;
}
byte* addr = wasm_context_->mem_start + operand.offset + index;
WasmValue result(
converter<ctype, mtype>{}(ReadLittleEndianValue<mtype>(addr)));
Push(result);
len = 1 + operand.length;
if (FLAG_wasm_trace_memory) {
tracing::TraceMemoryOperation(
tracing::kWasmInterpreted, false, rep, operand.offset + index,
code->function->func_index, static_cast<int>(pc),
wasm_context_->mem_start);
}
return true;
}
template <typename ctype, typename mtype>
bool ExecuteStore(Decoder* decoder, InterpreterCode* code, pc_t pc, int& len,
MachineRepresentation rep) {
MemoryAccessOperand<Decoder::kNoValidate> operand(decoder, code->at(pc),
sizeof(ctype));
ctype val = Pop().to<ctype>();
uint32_t index = Pop().to<uint32_t>();
if (!BoundsCheck<mtype>(wasm_context_->mem_size, operand.offset, index)) {
DoTrap(kTrapMemOutOfBounds, pc);
return false;
}
byte* addr = wasm_context_->mem_start + operand.offset + index;
WriteLittleEndianValue<mtype>(addr, converter<mtype, ctype>{}(val));
len = 1 + operand.length;
if (FLAG_wasm_trace_memory) {
tracing::TraceMemoryOperation(
tracing::kWasmInterpreted, true, rep, operand.offset + index,
code->function->func_index, static_cast<int>(pc),
wasm_context_->mem_start);
}
return true;
}
// Check if our control stack (frames_) exceeds the limit. Trigger stack
// overflow if it does, and unwinding the current frame.
// Returns true if execution can continue, false if the current activation was
// fully unwound.
// Do call this function immediately *after* pushing a new frame. The pc of
// the top frame will be reset to 0 if the stack check fails.
bool DoStackCheck() WARN_UNUSED_RESULT {
// Sum up the size of all dynamically growing structures.
if (V8_LIKELY(frames_.size() <= kV8MaxWasmInterpretedStackSize)) {
return true;
}
if (!codemap()->has_instance()) {
// In test mode: Just abort.
FATAL("wasm interpreter: stack overflow");
}
// The pc of the top frame is initialized to the first instruction. We reset
// it to 0 here such that we report the same position as in compiled code.
frames_.back().pc = 0;
Isolate* isolate = codemap()->instance()->GetIsolate();
HandleScope handle_scope(isolate);
isolate->StackOverflow();
return HandleException(isolate) == WasmInterpreter::Thread::HANDLED;
}
void Execute(InterpreterCode* code, pc_t pc, int max) {
DCHECK_NOT_NULL(code->side_table);
DCHECK(!frames_.empty());
// There must be enough space on the stack to hold the arguments, locals,
// and the value stack.
DCHECK_LE(code->function->sig->parameter_count() +
code->locals.type_list.size() +
code->side_table->max_stack_height_,
stack_limit_ - stack_start_ - frames_.back().sp);
Decoder decoder(code->start, code->end);
pc_t limit = code->end - code->start;
bool hit_break = false;
while (true) {
#define PAUSE_IF_BREAK_FLAG(flag) \
if (V8_UNLIKELY(break_flags_ & WasmInterpreter::BreakFlag::flag)) { \
hit_break = true; \
max = 0; \
}
DCHECK_GT(limit, pc);
DCHECK_NOT_NULL(code->start);
// Do first check for a breakpoint, in order to set hit_break correctly.
const char* skip = " ";
int len = 1;
byte opcode = code->start[pc];
byte orig = opcode;
if (V8_UNLIKELY(opcode == kInternalBreakpoint)) {
orig = code->orig_start[pc];
if (SkipBreakpoint(code, pc)) {
// skip breakpoint by switching on original code.
skip = "[skip] ";
} else {
TRACE("@%-3zu: [break] %-24s:", pc,
WasmOpcodes::OpcodeName(static_cast<WasmOpcode>(orig)));
TraceValueStack();
TRACE("\n");
hit_break = true;
break;
}
}
// If max is 0, break. If max is positive (a limit is set), decrement it.
if (max == 0) break;
if (max > 0) --max;
USE(skip);
TRACE("@%-3zu: %s%-24s:", pc, skip,
WasmOpcodes::OpcodeName(static_cast<WasmOpcode>(orig)));
TraceValueStack();
TRACE("\n");
#ifdef DEBUG
// Compute the stack effect of this opcode, and verify later that the
// stack was modified accordingly.
std::pair<uint32_t, uint32_t> stack_effect = wasm::StackEffect(
codemap_->module(), frames_.back().code->function->sig,
code->orig_start + pc, code->orig_end);
sp_t expected_new_stack_height =
StackHeight() - stack_effect.first + stack_effect.second;
#endif
switch (orig) {
case kExprNop:
break;
case kExprBlock: {
BlockTypeOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
len = 1 + operand.length;
break;
}
case kExprLoop: {
BlockTypeOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
len = 1 + operand.length;
break;
}
case kExprIf: {
BlockTypeOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
WasmValue cond = Pop();
bool is_true = cond.to<uint32_t>() != 0;
if (is_true) {
// fall through to the true block.
len = 1 + operand.length;
TRACE(" true => fallthrough\n");
} else {
len = LookupTargetDelta(code, pc);
TRACE(" false => @%zu\n", pc + len);
}
break;
}
case kExprElse: {
len = LookupTargetDelta(code, pc);
TRACE(" end => @%zu\n", pc + len);
break;
}
case kExprSelect: {
WasmValue cond = Pop();
WasmValue fval = Pop();
WasmValue tval = Pop();
Push(cond.to<int32_t>() != 0 ? tval : fval);
break;
}
case kExprBr: {
BreakDepthOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
len = DoBreak(code, pc, operand.depth);
TRACE(" br => @%zu\n", pc + len);
break;
}
case kExprBrIf: {
BreakDepthOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
WasmValue cond = Pop();
bool is_true = cond.to<uint32_t>() != 0;
if (is_true) {
len = DoBreak(code, pc, operand.depth);
TRACE(" br_if => @%zu\n", pc + len);
} else {
TRACE(" false => fallthrough\n");
len = 1 + operand.length;
}
break;
}
case kExprBrTable: {
BranchTableOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
BranchTableIterator<Decoder::kNoValidate> iterator(&decoder, operand);
uint32_t key = Pop().to<uint32_t>();
uint32_t depth = 0;
if (key >= operand.table_count) key = operand.table_count;
for (uint32_t i = 0; i <= key; i++) {
DCHECK(iterator.has_next());
depth = iterator.next();
}
len = key + DoBreak(code, pc + key, static_cast<size_t>(depth));
TRACE(" br[%u] => @%zu\n", key, pc + key + len);
break;
}
case kExprReturn: {
size_t arity = code->function->sig->return_count();
if (!DoReturn(&decoder, &code, &pc, &limit, arity)) return;
PAUSE_IF_BREAK_FLAG(AfterReturn);
continue;
}
case kExprUnreachable: {
return DoTrap(kTrapUnreachable, pc);
}
case kExprEnd: {
break;
}
case kExprI32Const: {
ImmI32Operand<Decoder::kNoValidate> operand(&decoder, code->at(pc));
Push(WasmValue(operand.value));
len = 1 + operand.length;
break;
}
case kExprI64Const: {
ImmI64Operand<Decoder::kNoValidate> operand(&decoder, code->at(pc));
Push(WasmValue(operand.value));
len = 1 + operand.length;
break;
}
case kExprF32Const: {
ImmF32Operand<Decoder::kNoValidate> operand(&decoder, code->at(pc));
Push(WasmValue(operand.value));
len = 1 + operand.length;
break;
}
case kExprF64Const: {
ImmF64Operand<Decoder::kNoValidate> operand(&decoder, code->at(pc));
Push(WasmValue(operand.value));
len = 1 + operand.length;
break;
}
case kExprGetLocal: {
LocalIndexOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
Push(GetStackValue(frames_.back().sp + operand.index));
len = 1 + operand.length;
break;
}
case kExprSetLocal: {
LocalIndexOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
WasmValue val = Pop();
SetStackValue(frames_.back().sp + operand.index, val);
len = 1 + operand.length;
break;
}
case kExprTeeLocal: {
LocalIndexOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
WasmValue val = Pop();
SetStackValue(frames_.back().sp + operand.index, val);
Push(val);
len = 1 + operand.length;
break;
}
case kExprDrop: {
Pop();
break;
}
case kExprCallFunction: {
CallFunctionOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
InterpreterCode* target = codemap()->GetCode(operand.index);
if (target->function->imported) {
CommitPc(pc);
ExternalCallResult result =
CallImportedFunction(target->function->func_index);
switch (result.type) {
case ExternalCallResult::INTERNAL:
// The import is a function of this instance. Call it directly.
target = result.interpreter_code;
DCHECK(!target->function->imported);
break;
case ExternalCallResult::INVALID_FUNC:
case ExternalCallResult::SIGNATURE_MISMATCH:
// Direct calls are checked statically.
UNREACHABLE();
case ExternalCallResult::EXTERNAL_RETURNED:
PAUSE_IF_BREAK_FLAG(AfterCall);
len = 1 + operand.length;
break;
case ExternalCallResult::EXTERNAL_UNWOUND:
return;
}
if (result.type != ExternalCallResult::INTERNAL) break;
}
// Execute an internal call.
if (!DoCall(&decoder, target, &pc, &limit)) return;
code = target;
PAUSE_IF_BREAK_FLAG(AfterCall);
continue; // don't bump pc
} break;
case kExprCallIndirect: {
CallIndirectOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
uint32_t entry_index = Pop().to<uint32_t>();
// Assume only one table for now.
DCHECK_LE(module()->function_tables.size(), 1u);
ExternalCallResult result =
CallIndirectFunction(0, entry_index, operand.index);
switch (result.type) {
case ExternalCallResult::INTERNAL:
// The import is a function of this instance. Call it directly.
if (!DoCall(&decoder, result.interpreter_code, &pc, &limit))
return;
code = result.interpreter_code;
PAUSE_IF_BREAK_FLAG(AfterCall);
continue; // don't bump pc
case ExternalCallResult::INVALID_FUNC:
return DoTrap(kTrapFuncInvalid, pc);
case ExternalCallResult::SIGNATURE_MISMATCH:
return DoTrap(kTrapFuncSigMismatch, pc);
case ExternalCallResult::EXTERNAL_RETURNED:
PAUSE_IF_BREAK_FLAG(AfterCall);
len = 1 + operand.length;
break;
case ExternalCallResult::EXTERNAL_UNWOUND:
return;
}
} break;
case kExprGetGlobal: {
GlobalIndexOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
const WasmGlobal* global = &module()->globals[operand.index];
byte* ptr = wasm_context_->globals_start + global->offset;
WasmValue val;
switch (global->type) {
#define CASE_TYPE(wasm, ctype) \
case kWasm##wasm: \
val = WasmValue(*reinterpret_cast<ctype*>(ptr)); \
break;
WASM_CTYPES(CASE_TYPE)
#undef CASE_TYPE
default:
UNREACHABLE();
}
Push(val);
len = 1 + operand.length;
break;
}
case kExprSetGlobal: {
GlobalIndexOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
const WasmGlobal* global = &module()->globals[operand.index];
byte* ptr = wasm_context_->globals_start + global->offset;
WasmValue val = Pop();
switch (global->type) {
#define CASE_TYPE(wasm, ctype) \
case kWasm##wasm: \
*reinterpret_cast<ctype*>(ptr) = val.to<ctype>(); \
break;
WASM_CTYPES(CASE_TYPE)
#undef CASE_TYPE
default:
UNREACHABLE();
}
len = 1 + operand.length;
break;
}
#define LOAD_CASE(name, ctype, mtype, rep) \
case kExpr##name: { \
if (!ExecuteLoad<ctype, mtype>(&decoder, code, pc, len, \
MachineRepresentation::rep)) \
return; \
break; \
}
LOAD_CASE(I32LoadMem8S, int32_t, int8_t, kWord8);
LOAD_CASE(I32LoadMem8U, int32_t, uint8_t, kWord8);
LOAD_CASE(I32LoadMem16S, int32_t, int16_t, kWord16);
LOAD_CASE(I32LoadMem16U, int32_t, uint16_t, kWord16);
LOAD_CASE(I64LoadMem8S, int64_t, int8_t, kWord8);
LOAD_CASE(I64LoadMem8U, int64_t, uint8_t, kWord16);
LOAD_CASE(I64LoadMem16S, int64_t, int16_t, kWord16);
LOAD_CASE(I64LoadMem16U, int64_t, uint16_t, kWord16);
LOAD_CASE(I64LoadMem32S, int64_t, int32_t, kWord32);
LOAD_CASE(I64LoadMem32U, int64_t, uint32_t, kWord32);
LOAD_CASE(I32LoadMem, int32_t, int32_t, kWord32);
LOAD_CASE(I64LoadMem, int64_t, int64_t, kWord64);
LOAD_CASE(F32LoadMem, Float32, uint32_t, kFloat32);
LOAD_CASE(F64LoadMem, Float64, uint64_t, kFloat64);
#undef LOAD_CASE
#define STORE_CASE(name, ctype, mtype, rep) \
case kExpr##name: { \
if (!ExecuteStore<ctype, mtype>(&decoder, code, pc, len, \
MachineRepresentation::rep)) \
return; \
break; \
}
STORE_CASE(I32StoreMem8, int32_t, int8_t, kWord8);
STORE_CASE(I32StoreMem16, int32_t, int16_t, kWord16);
STORE_CASE(I64StoreMem8, int64_t, int8_t, kWord8);
STORE_CASE(I64StoreMem16, int64_t, int16_t, kWord16);
STORE_CASE(I64StoreMem32, int64_t, int32_t, kWord32);
STORE_CASE(I32StoreMem, int32_t, int32_t, kWord32);
STORE_CASE(I64StoreMem, int64_t, int64_t, kWord64);
STORE_CASE(F32StoreMem, Float32, uint32_t, kFloat32);
STORE_CASE(F64StoreMem, Float64, uint64_t, kFloat64);
#undef STORE_CASE
#define ASMJS_LOAD_CASE(name, ctype, mtype, defval) \
case kExpr##name: { \
uint32_t index = Pop().to<uint32_t>(); \
ctype result; \
if (!BoundsCheck<mtype>(wasm_context_->mem_size, 0, index)) { \
result = defval; \
} else { \
byte* addr = wasm_context_->mem_start + index; \
/* TODO(titzer): alignment for asmjs load mem? */ \
result = static_cast<ctype>(*reinterpret_cast<mtype*>(addr)); \
} \
Push(WasmValue(result)); \
break; \
}
ASMJS_LOAD_CASE(I32AsmjsLoadMem8S, int32_t, int8_t, 0);
ASMJS_LOAD_CASE(I32AsmjsLoadMem8U, int32_t, uint8_t, 0);
ASMJS_LOAD_CASE(I32AsmjsLoadMem16S, int32_t, int16_t, 0);
ASMJS_LOAD_CASE(I32AsmjsLoadMem16U, int32_t, uint16_t, 0);
ASMJS_LOAD_CASE(I32AsmjsLoadMem, int32_t, int32_t, 0);
ASMJS_LOAD_CASE(F32AsmjsLoadMem, float, float,
std::numeric_limits<float>::quiet_NaN());
ASMJS_LOAD_CASE(F64AsmjsLoadMem, double, double,
std::numeric_limits<double>::quiet_NaN());
#undef ASMJS_LOAD_CASE
#define ASMJS_STORE_CASE(name, ctype, mtype) \
case kExpr##name: { \
WasmValue val = Pop(); \
uint32_t index = Pop().to<uint32_t>(); \
if (BoundsCheck<mtype>(wasm_context_->mem_size, 0, index)) { \
byte* addr = wasm_context_->mem_start + index; \
/* TODO(titzer): alignment for asmjs store mem? */ \
*(reinterpret_cast<mtype*>(addr)) = static_cast<mtype>(val.to<ctype>()); \
} \
Push(val); \
break; \
}
ASMJS_STORE_CASE(I32AsmjsStoreMem8, int32_t, int8_t);
ASMJS_STORE_CASE(I32AsmjsStoreMem16, int32_t, int16_t);
ASMJS_STORE_CASE(I32AsmjsStoreMem, int32_t, int32_t);
ASMJS_STORE_CASE(F32AsmjsStoreMem, float, float);
ASMJS_STORE_CASE(F64AsmjsStoreMem, double, double);
#undef ASMJS_STORE_CASE
case kExprGrowMemory: {
MemoryIndexOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
uint32_t delta_pages = Pop().to<uint32_t>();
Handle<WasmInstanceObject> instance =
codemap()->maybe_instance().ToHandleChecked();
DCHECK_EQ(wasm_context_, instance->wasm_context()->get());
Isolate* isolate = instance->GetIsolate();
int32_t result =
WasmInstanceObject::GrowMemory(isolate, instance, delta_pages);
Push(WasmValue(result));
len = 1 + operand.length;
break;
}
case kExprMemorySize: {
MemoryIndexOperand<Decoder::kNoValidate> operand(&decoder,
code->at(pc));
Push(WasmValue(static_cast<uint32_t>(wasm_context_->mem_size /
WasmModule::kPageSize)));
len = 1 + operand.length;
break;
}
// We need to treat kExprI32ReinterpretF32 and kExprI64ReinterpretF64
// specially to guarantee that the quiet bit of a NaN is preserved on
// ia32 by the reinterpret casts.
case kExprI32ReinterpretF32: {
WasmValue val = Pop();
Push(WasmValue(ExecuteI32ReinterpretF32(val)));
break;
}
case kExprI64ReinterpretF64: {
WasmValue val = Pop();
Push(WasmValue(ExecuteI64ReinterpretF64(val)));
break;
}
#define EXECUTE_SIMPLE_BINOP(name, ctype, op) \
case kExpr##name: { \
WasmValue rval = Pop(); \
WasmValue lval = Pop(); \
auto result = lval.to<ctype>() op rval.to<ctype>(); \
possible_nondeterminism_ |= has_nondeterminism(result); \
Push(WasmValue(result)); \
break; \
}
FOREACH_SIMPLE_BINOP(EXECUTE_SIMPLE_BINOP)
#undef EXECUTE_SIMPLE_BINOP
#define EXECUTE_OTHER_BINOP(name, ctype) \
case kExpr##name: { \
TrapReason trap = kTrapCount; \
ctype rval = Pop().to<ctype>(); \
ctype lval = Pop().to<ctype>(); \
auto result = Execute##name(lval, rval, &trap); \
possible_nondeterminism_ |= has_nondeterminism(result); \
if (trap != kTrapCount) return DoTrap(trap, pc); \
Push(WasmValue(result)); \
break; \
}
FOREACH_OTHER_BINOP(EXECUTE_OTHER_BINOP)
#undef EXECUTE_OTHER_BINOP
#define EXECUTE_OTHER_UNOP(name, ctype) \
case kExpr##name: { \
TrapReason trap = kTrapCount; \
ctype val = Pop().to<ctype>(); \
auto result = Execute##name(val, &trap); \
possible_nondeterminism_ |= has_nondeterminism(result); \
if (trap != kTrapCount) return DoTrap(trap, pc); \
Push(WasmValue(result)); \
break; \
}
FOREACH_OTHER_UNOP(EXECUTE_OTHER_UNOP)
#undef EXECUTE_OTHER_UNOP
default:
V8_Fatal(__FILE__, __LINE__, "Unknown or unimplemented opcode #%d:%s",
code->start[pc], OpcodeName(code->start[pc]));
UNREACHABLE();
}
#ifdef DEBUG
if (!WasmOpcodes::IsControlOpcode(static_cast<WasmOpcode>(opcode))) {
DCHECK_EQ(expected_new_stack_height, StackHeight());
}
#endif
pc += len;
if (pc == limit) {
// Fell off end of code; do an implicit return.
TRACE("@%-3zu: ImplicitReturn\n", pc);
if (!DoReturn(&decoder, &code, &pc, &limit,
code->function->sig->return_count()))
return;
PAUSE_IF_BREAK_FLAG(AfterReturn);
}
#undef PAUSE_IF_BREAK_FLAG
}
state_ = WasmInterpreter::PAUSED;
break_pc_ = hit_break ? pc : kInvalidPc;
CommitPc(pc);
}
WasmValue Pop() {
DCHECK_GT(frames_.size(), 0);
DCHECK_GT(StackHeight(), frames_.back().llimit()); // can't pop into locals
return *--sp_;
}
void PopN(int n) {
DCHECK_GE(StackHeight(), n);
DCHECK_GT(frames_.size(), 0);
// Check that we don't pop into locals.
DCHECK_GE(StackHeight() - n, frames_.back().llimit());
sp_ -= n;
}
WasmValue PopArity(size_t arity) {
if (arity == 0) return WasmValue();
CHECK_EQ(1, arity);
return Pop();
}
void Push(WasmValue val) {
DCHECK_NE(kWasmStmt, val.type());
DCHECK_LE(1, stack_limit_ - sp_);
*sp_++ = val;
}
void Push(WasmValue* vals, size_t arity) {
DCHECK_LE(arity, stack_limit_ - sp_);
for (WasmValue *val = vals, *end = vals + arity; val != end; ++val) {
DCHECK_NE(kWasmStmt, val->type());
}
memcpy(sp_, vals, arity * sizeof(*sp_));
sp_ += arity;
}
void EnsureStackSpace(size_t size) {
if (V8_LIKELY(static_cast<size_t>(stack_limit_ - sp_) >= size)) return;
size_t old_size = stack_limit_ - stack_start_;
size_t requested_size =
base::bits::RoundUpToPowerOfTwo64((sp_ - stack_start_) + size);
size_t new_size = Max(size_t{8}, Max(2 * old_size, requested_size));
WasmValue* new_stack = zone_->NewArray<WasmValue>(new_size);
memcpy(new_stack, stack_start_, old_size * sizeof(*sp_));
sp_ = new_stack + (sp_ - stack_start_);
stack_start_ = new_stack;
stack_limit_ = new_stack + new_size;
}
sp_t StackHeight() { return sp_ - stack_start_; }
void TraceValueStack() {
#ifdef DEBUG
if (!FLAG_trace_wasm_interpreter) return;
Frame* top = frames_.size() > 0 ? &frames_.back() : nullptr;
sp_t sp = top ? top->sp : 0;
sp_t plimit = top ? top->plimit() : 0;
sp_t llimit = top ? top->llimit() : 0;
for (size_t i = sp; i < StackHeight(); ++i) {
if (i < plimit)
PrintF(" p%zu:", i);
else if (i < llimit)
PrintF(" l%zu:", i);
else
PrintF(" s%zu:", i);
WasmValue val = GetStackValue(i);
switch (val.type()) {
case kWasmI32:
PrintF("i32:%d", val.to<int32_t>());
break;
case kWasmI64:
PrintF("i64:%" PRId64 "", val.to<int64_t>());
break;
case kWasmF32:
PrintF("f32:%f", val.to<float>());
break;
case kWasmF64:
PrintF("f64:%lf", val.to<double>());
break;
case kWasmStmt:
PrintF("void");
break;
default:
UNREACHABLE();
break;
}
}
#endif // DEBUG
}
ExternalCallResult TryHandleException(Isolate* isolate) {
if (HandleException(isolate) == WasmInterpreter::Thread::UNWOUND) {
return {ExternalCallResult::EXTERNAL_UNWOUND};
}
return {ExternalCallResult::EXTERNAL_RETURNED};
}
// TODO(clemensh): Remove this, call JS via existing wasm-to-js wrapper, using
// CallExternalWasmFunction.
ExternalCallResult CallExternalJSFunction(Isolate* isolate, Handle<Code> code,
FunctionSig* signature) {
Handle<HeapObject> target = UnwrapWasmToJSWrapper(isolate, code);
if (target.is_null()) {
isolate->Throw(*isolate->factory()->NewTypeError(
MessageTemplate::kWasmTrapTypeError));
return TryHandleException(isolate);
}
#if DEBUG
std::ostringstream oss;
target->HeapObjectShortPrint(oss);
TRACE(" => Calling imported function %s\n", oss.str().c_str());
#endif
int num_args = static_cast<int>(signature->parameter_count());
// Get all arguments as JS values.
std::vector<Handle<Object>> args;
args.reserve(num_args);
WasmValue* wasm_args = sp_ - num_args;
for (int i = 0; i < num_args; ++i) {
args.push_back(WasmValueToNumber(isolate->factory(), wasm_args[i],
signature->GetParam(i)));
}
// The receiver is the global proxy if in sloppy mode (default), undefined
// if in strict mode.
Handle<Object> receiver = isolate->global_proxy();
if (target->IsJSFunction() &&
is_strict(JSFunction::cast(*target)->shared()->language_mode())) {
receiver = isolate->factory()->undefined_value();
}
MaybeHandle<Object> maybe_retval =
Execution::Call(isolate, target, receiver, num_args, args.data());
if (maybe_retval.is_null()) return TryHandleException(isolate);
Handle<Object> retval = maybe_retval.ToHandleChecked();
// Pop arguments off the stack.
sp_ -= num_args;
// Push return values.
if (signature->return_count() > 0) {
// TODO(wasm): Handle multiple returns.
DCHECK_EQ(1, signature->return_count());
WasmValue value =
ToWebAssemblyValue(isolate, retval, signature->GetReturn());
if (value.type() == kWasmStmt) return TryHandleException(isolate);
Push(value);
}
return {ExternalCallResult::EXTERNAL_RETURNED};
}
ExternalCallResult CallExternalWasmFunction(Isolate* isolate,
Handle<Code> code,
FunctionSig* sig) {
Handle<WasmDebugInfo> debug_info(codemap()->instance()->debug_info(),
isolate);
Handle<JSFunction> wasm_entry =
WasmDebugInfo::GetCWasmEntry(debug_info, sig);
TRACE(" => Calling external wasm function\n");
// Copy the arguments to one buffer.
// TODO(clemensh): Introduce a helper for all argument buffer
// con-/destruction.
int num_args = static_cast<int>(sig->parameter_count());
std::vector<uint8_t> arg_buffer(num_args * 8);
size_t offset = 0;
WasmValue* wasm_args = sp_ - num_args;
for (int i = 0; i < num_args; ++i) {
uint32_t param_size = 1 << ElementSizeLog2Of(sig->GetParam(i));
if (arg_buffer.size() < offset + param_size) {
arg_buffer.resize(std::max(2 * arg_buffer.size(), offset + param_size));
}
switch (sig->GetParam(i)) {
case kWasmI32:
WriteUnalignedValue(arg_buffer.data() + offset,
wasm_args[i].to<uint32_t>());
break;
case kWasmI64:
WriteUnalignedValue(arg_buffer.data() + offset,
wasm_args[i].to<uint64_t>());
break;
case kWasmF32:
WriteUnalignedValue(arg_buffer.data() + offset,
wasm_args[i].to<float>());
break;
case kWasmF64:
WriteUnalignedValue(arg_buffer.data() + offset,
wasm_args[i].to<double>());
break;
default:
UNIMPLEMENTED();
}
offset += param_size;
}
// Wrap the arg_buffer data pointer in a handle. As this is an aligned
// pointer, to the GC it will look like a Smi.
Handle<Object> arg_buffer_obj(reinterpret_cast<Object*>(arg_buffer.data()),
isolate);
DCHECK(!arg_buffer_obj->IsHeapObject());
Handle<Object> args[compiler::CWasmEntryParameters::kNumParameters];
args[compiler::CWasmEntryParameters::kCodeObject] = code;
args[compiler::CWasmEntryParameters::kArgumentsBuffer] = arg_buffer_obj;
Handle<Object> receiver = isolate->factory()->undefined_value();
trap_handler::SetThreadInWasm();
MaybeHandle<Object> maybe_retval =
Execution::Call(isolate, wasm_entry, receiver, arraysize(args), args);
TRACE(" => External wasm function returned%s\n",
maybe_retval.is_null() ? " with exception" : "");
if (maybe_retval.is_null()) {
DCHECK(!trap_handler::IsThreadInWasm());
return TryHandleException(isolate);
}
trap_handler::ClearThreadInWasm();
// Pop arguments off the stack.
sp_ -= num_args;
// Push return values.
if (sig->return_count() > 0) {
// TODO(wasm): Handle multiple returns.
DCHECK_EQ(1, sig->return_count());
switch (sig->GetReturn()) {
case kWasmI32:
Push(WasmValue(ReadUnalignedValue<uint32_t>(arg_buffer.data())));
break;
case kWasmI64:
Push(WasmValue(ReadUnalignedValue<uint64_t>(arg_buffer.data())));
break;
case kWasmF32:
Push(WasmValue(ReadUnalignedValue<float>(arg_buffer.data())));
break;
case kWasmF64:
Push(WasmValue(ReadUnalignedValue<double>(arg_buffer.data())));
break;
default:
UNIMPLEMENTED();
}
}
return {ExternalCallResult::EXTERNAL_RETURNED};
}
ExternalCallResult CallCodeObject(Isolate* isolate, Handle<Code> code,
FunctionSig* signature) {
DCHECK(AllowHandleAllocation::IsAllowed());
DCHECK(AllowHeapAllocation::IsAllowed());
if (code->kind() == Code::WASM_FUNCTION) {
FixedArray* deopt_data = code->deoptimization_data();
DCHECK_EQ(2, deopt_data->length());
WasmInstanceObject* target_instance =
WasmInstanceObject::cast(WeakCell::cast(deopt_data->get(0))->value());
if (target_instance != codemap()->instance()) {
return CallExternalWasmFunction(isolate, code, signature);
}
int target_func_idx = Smi::ToInt(deopt_data->get(1));
DCHECK_LE(0, target_func_idx);
return {ExternalCallResult::INTERNAL,
codemap()->GetCode(target_func_idx)};
}
return CallExternalJSFunction(isolate, code, signature);
}
ExternalCallResult CallImportedFunction(uint32_t function_index) {
// Use a new HandleScope to avoid leaking / accumulating handles in the
// outer scope.
Isolate* isolate = codemap()->instance()->GetIsolate();
HandleScope handle_scope(isolate);
Handle<Code> target(codemap()->GetImportedFunction(function_index),
isolate);
return CallCodeObject(isolate, target,
codemap()->module()->functions[function_index].sig);
}
ExternalCallResult CallIndirectFunction(uint32_t table_index,
uint32_t entry_index,
uint32_t sig_index) {
if (!codemap()->has_instance() ||
!codemap()->instance()->compiled_module()->has_function_tables()) {
// No instance. Rely on the information stored in the WasmModule.
// TODO(wasm): This is only needed for testing. Refactor testing to use
// the same paths as production.
InterpreterCode* code =
codemap()->GetIndirectCode(table_index, entry_index);
if (!code) return {ExternalCallResult::INVALID_FUNC};
if (code->function->sig_index != sig_index) {
// If not an exact match, we have to do a canonical check.
int function_canonical_id =
module()->signature_ids[code->function->sig_index];
int expected_canonical_id = module()->signature_ids[sig_index];
DCHECK_EQ(function_canonical_id,
module()->signature_map.Find(code->function->sig));
if (function_canonical_id != expected_canonical_id) {
return {ExternalCallResult::SIGNATURE_MISMATCH};
}
}
return {ExternalCallResult::INTERNAL, code};
}
WasmCompiledModule* compiled_module =
codemap()->instance()->compiled_module();
Isolate* isolate = compiled_module->GetIsolate();
Code* target;
{
DisallowHeapAllocation no_gc;
// Get function to be called directly from the live instance to see latest
// changes to the tables.
// Canonicalize signature index.
uint32_t canonical_sig_index = module()->signature_ids[sig_index];
DCHECK_EQ(canonical_sig_index,
module()->signature_map.Find(module()->signatures[sig_index]));
// Check signature.
FixedArray* sig_tables = compiled_module->ptr_to_signature_tables();
if (table_index >= static_cast<uint32_t>(sig_tables->length())) {
return {ExternalCallResult::INVALID_FUNC};
}
// Reconstitute the global handle to sig_table, and, further below,
// to the function table, from the address stored in the
// respective table of tables.
int table_index_as_int = static_cast<int>(table_index);
Handle<FixedArray> sig_table(reinterpret_cast<FixedArray**>(
WasmCompiledModule::GetTableValue(sig_tables, table_index_as_int)));
if (entry_index >= static_cast<uint32_t>(sig_table->length())) {
return {ExternalCallResult::INVALID_FUNC};
}
int found_sig = Smi::ToInt(sig_table->get(static_cast<int>(entry_index)));
if (static_cast<uint32_t>(found_sig) != canonical_sig_index) {
return {ExternalCallResult::SIGNATURE_MISMATCH};
}
// Get code object.
FixedArray* fun_tables = compiled_module->ptr_to_function_tables();
DCHECK_EQ(sig_tables->length(), fun_tables->length());
Handle<FixedArray> fun_table(reinterpret_cast<FixedArray**>(
WasmCompiledModule::GetTableValue(fun_tables, table_index_as_int)));
DCHECK_EQ(sig_table->length(), fun_table->length());
target = Code::cast(fun_table->get(static_cast<int>(entry_index)));
}
// Call the code object. Use a new HandleScope to avoid leaking /
// accumulating handles in the outer scope.
HandleScope handle_scope(isolate);
FunctionSig* signature =
&codemap()->module()->signatures[table_index][sig_index];
return CallCodeObject(isolate, handle(target, isolate), signature);
}
inline Activation current_activation() {
return activations_.empty() ? Activation(0, 0) : activations_.back();
}
};
class InterpretedFrameImpl {
public:
InterpretedFrameImpl(ThreadImpl* thread, int index)
: thread_(thread), index_(index) {
DCHECK_LE(0, index);
}
const WasmFunction* function() const { return frame()->code->function; }
int pc() const {
DCHECK_LE(0, frame()->pc);
DCHECK_GE(kMaxInt, frame()->pc);
return static_cast<int>(frame()->pc);
}
int GetParameterCount() const {
DCHECK_GE(kMaxInt, function()->sig->parameter_count());
return static_cast<int>(function()->sig->parameter_count());
}
int GetLocalCount() const {
size_t num_locals = function()->sig->parameter_count() +
frame()->code->locals.type_list.size();
DCHECK_GE(kMaxInt, num_locals);
return static_cast<int>(num_locals);
}
int GetStackHeight() const {
bool is_top_frame =
static_cast<size_t>(index_) + 1 == thread_->frames_.size();
size_t stack_limit =
is_top_frame ? thread_->StackHeight() : thread_->frames_[index_ + 1].sp;
DCHECK_LE(frame()->sp, stack_limit);
size_t frame_size = stack_limit - frame()->sp;
DCHECK_LE(GetLocalCount(), frame_size);
return static_cast<int>(frame_size) - GetLocalCount();
}
WasmValue GetLocalValue(int index) const {
DCHECK_LE(0, index);
DCHECK_GT(GetLocalCount(), index);
return thread_->GetStackValue(static_cast<int>(frame()->sp) + index);
}
WasmValue GetStackValue(int index) const {
DCHECK_LE(0, index);
// Index must be within the number of stack values of this frame.
DCHECK_GT(GetStackHeight(), index);
return thread_->GetStackValue(static_cast<int>(frame()->sp) +
GetLocalCount() + index);
}
private:
ThreadImpl* thread_;
int index_;
ThreadImpl::Frame* frame() const {
DCHECK_GT(thread_->frames_.size(), index_);
return &thread_->frames_[index_];
}
};
// Converters between WasmInterpreter::Thread and WasmInterpreter::ThreadImpl.
// Thread* is the public interface, without knowledge of the object layout.
// This cast is potentially risky, but as long as we always cast it back before
// accessing any data, it should be fine. UBSan is not complaining.
WasmInterpreter::Thread* ToThread(ThreadImpl* impl) {
return reinterpret_cast<WasmInterpreter::Thread*>(impl);
}
ThreadImpl* ToImpl(WasmInterpreter::Thread* thread) {
return reinterpret_cast<ThreadImpl*>(thread);
}
// Same conversion for InterpretedFrame and InterpretedFrameImpl.
InterpretedFrame* ToFrame(InterpretedFrameImpl* impl) {
return reinterpret_cast<InterpretedFrame*>(impl);
}
const InterpretedFrameImpl* ToImpl(const InterpretedFrame* frame) {
return reinterpret_cast<const InterpretedFrameImpl*>(frame);
}
//============================================================================
// Implementation details of the heap objects scope.
//============================================================================
class HeapObjectsScopeImpl {
public:
HeapObjectsScopeImpl(CodeMap* codemap, Handle<WasmInstanceObject> instance)
: codemap_(codemap), needs_reset(!codemap_->has_instance()) {
if (needs_reset) {
instance_ = handle(*instance);
codemap_->SetInstanceObject(instance_);
} else {
DCHECK_EQ(*instance, codemap_->instance());
return;
}
}
~HeapObjectsScopeImpl() {
if (!needs_reset) return;
DCHECK_EQ(*instance_, codemap_->instance());
codemap_->ClearInstanceObject();
// Clear the handle, such that anyone who accidentally copied them will
// notice.
*instance_.location() = nullptr;
}
private:
CodeMap* codemap_;
Handle<WasmInstanceObject> instance_;
bool needs_reset;
};
} // namespace
//============================================================================
// Implementation of the pimpl idiom for WasmInterpreter::Thread.
// Instead of placing a pointer to the ThreadImpl inside of the Thread object,
// we just reinterpret_cast them. ThreadImpls are only allocated inside this
// translation unit anyway.
//============================================================================
WasmInterpreter::State WasmInterpreter::Thread::state() {
return ToImpl(this)->state();
}
void WasmInterpreter::Thread::InitFrame(const WasmFunction* function,
WasmValue* args) {
ToImpl(this)->InitFrame(function, args);
}
WasmInterpreter::State WasmInterpreter::Thread::Run(int num_steps) {
return ToImpl(this)->Run(num_steps);
}
void WasmInterpreter::Thread::Pause() { return ToImpl(this)->Pause(); }
void WasmInterpreter::Thread::Reset() { return ToImpl(this)->Reset(); }
WasmInterpreter::Thread::ExceptionHandlingResult
WasmInterpreter::Thread::HandleException(Isolate* isolate) {
return ToImpl(this)->HandleException(isolate);
}
pc_t WasmInterpreter::Thread::GetBreakpointPc() {
return ToImpl(this)->GetBreakpointPc();
}
int WasmInterpreter::Thread::GetFrameCount() {
return ToImpl(this)->GetFrameCount();
}
std::unique_ptr<InterpretedFrame> WasmInterpreter::Thread::GetFrame(int index) {
DCHECK_LE(0, index);
DCHECK_GT(GetFrameCount(), index);
return std::unique_ptr<InterpretedFrame>(
ToFrame(new InterpretedFrameImpl(ToImpl(this), index)));
}
WasmValue WasmInterpreter::Thread::GetReturnValue(int index) {
return ToImpl(this)->GetReturnValue(index);
}
TrapReason WasmInterpreter::Thread::GetTrapReason() {
return ToImpl(this)->GetTrapReason();
}
bool WasmInterpreter::Thread::PossibleNondeterminism() {
return ToImpl(this)->PossibleNondeterminism();
}
uint64_t WasmInterpreter::Thread::NumInterpretedCalls() {
return ToImpl(this)->NumInterpretedCalls();
}
void WasmInterpreter::Thread::AddBreakFlags(uint8_t flags) {
ToImpl(this)->AddBreakFlags(flags);
}
void WasmInterpreter::Thread::ClearBreakFlags() {
ToImpl(this)->ClearBreakFlags();
}
uint32_t WasmInterpreter::Thread::NumActivations() {
return ToImpl(this)->NumActivations();
}
uint32_t WasmInterpreter::Thread::StartActivation() {
return ToImpl(this)->StartActivation();
}
void WasmInterpreter::Thread::FinishActivation(uint32_t id) {
ToImpl(this)->FinishActivation(id);
}
uint32_t WasmInterpreter::Thread::ActivationFrameBase(uint32_t id) {
return ToImpl(this)->ActivationFrameBase(id);
}
//============================================================================
// The implementation details of the interpreter.
//============================================================================
class WasmInterpreterInternals : public ZoneObject {
public:
// Create a copy of the module bytes for the interpreter, since the passed
// pointer might be invalidated after constructing the interpreter.
const ZoneVector<uint8_t> module_bytes_;
CodeMap codemap_;
ZoneVector<ThreadImpl> threads_;
WasmInterpreterInternals(Isolate* isolate, Zone* zone,
const WasmModule* module,
const ModuleWireBytes& wire_bytes,
WasmContext* wasm_context)
: module_bytes_(wire_bytes.start(), wire_bytes.end(), zone),
codemap_(isolate, module, module_bytes_.data(), zone),
threads_(zone) {
threads_.emplace_back(zone, &codemap_, wasm_context);
}
};
//============================================================================
// Implementation of the public interface of the interpreter.
//============================================================================
WasmInterpreter::WasmInterpreter(Isolate* isolate, const WasmModule* module,
const ModuleWireBytes& wire_bytes,
WasmContext* wasm_context)
: zone_(isolate->allocator(), ZONE_NAME),
internals_(new (&zone_) WasmInterpreterInternals(
isolate, &zone_, module, wire_bytes, wasm_context)) {}
WasmInterpreter::~WasmInterpreter() { internals_->~WasmInterpreterInternals(); }
void WasmInterpreter::Run() { internals_->threads_[0].Run(); }
void WasmInterpreter::Pause() { internals_->threads_[0].Pause(); }
bool WasmInterpreter::SetBreakpoint(const WasmFunction* function, pc_t pc,
bool enabled) {
InterpreterCode* code = internals_->codemap_.GetCode(function);
size_t size = static_cast<size_t>(code->end - code->start);
// Check bounds for {pc}.
if (pc < code->locals.encoded_size || pc >= size) return false;
// Make a copy of the code before enabling a breakpoint.
if (enabled && code->orig_start == code->start) {
code->start = reinterpret_cast<byte*>(zone_.New(size));
memcpy(code->start, code->orig_start, size);
code->end = code->start + size;
}
bool prev = code->start[pc] == kInternalBreakpoint;
if (enabled) {
code->start[pc] = kInternalBreakpoint;
} else {
code->start[pc] = code->orig_start[pc];
}
return prev;
}
bool WasmInterpreter::GetBreakpoint(const WasmFunction* function, pc_t pc) {
InterpreterCode* code = internals_->codemap_.GetCode(function);
size_t size = static_cast<size_t>(code->end - code->start);
// Check bounds for {pc}.
if (pc < code->locals.encoded_size || pc >= size) return false;
// Check if a breakpoint is present at that place in the code.
return code->start[pc] == kInternalBreakpoint;
}
bool WasmInterpreter::SetTracing(const WasmFunction* function, bool enabled) {
UNIMPLEMENTED();
return false;
}
int WasmInterpreter::GetThreadCount() {
return 1; // only one thread for now.
}
WasmInterpreter::Thread* WasmInterpreter::GetThread(int id) {
CHECK_EQ(0, id); // only one thread for now.
return ToThread(&internals_->threads_[id]);
}
void WasmInterpreter::AddFunctionForTesting(const WasmFunction* function) {
internals_->codemap_.AddFunction(function, nullptr, nullptr);
}
void WasmInterpreter::SetFunctionCodeForTesting(const WasmFunction* function,
const byte* start,
const byte* end) {
internals_->codemap_.SetFunctionCode(function, start, end);
}
ControlTransferMap WasmInterpreter::ComputeControlTransfersForTesting(
Zone* zone, const WasmModule* module, const byte* start, const byte* end) {
// Create some dummy structures, to avoid special-casing the implementation
// just for testing.
FunctionSig sig(0, 0, nullptr);
WasmFunction function{&sig, 0, 0, {0, 0}, {0, 0}, false, false};
InterpreterCode code{
&function, BodyLocalDecls(zone), start, end, nullptr, nullptr, nullptr};
// Now compute and return the control transfers.
SideTable side_table(zone, module, &code);
return side_table.map_;
}
//============================================================================
// Implementation of the frame inspection interface.
//============================================================================
const WasmFunction* InterpretedFrame::function() const {
return ToImpl(this)->function();
}
int InterpretedFrame::pc() const { return ToImpl(this)->pc(); }
int InterpretedFrame::GetParameterCount() const {
return ToImpl(this)->GetParameterCount();
}
int InterpretedFrame::GetLocalCount() const {
return ToImpl(this)->GetLocalCount();
}
int InterpretedFrame::GetStackHeight() const {
return ToImpl(this)->GetStackHeight();
}
WasmValue InterpretedFrame::GetLocalValue(int index) const {
return ToImpl(this)->GetLocalValue(index);
}
WasmValue InterpretedFrame::GetStackValue(int index) const {
return ToImpl(this)->GetStackValue(index);
}
//============================================================================
// Public API of the heap objects scope.
//============================================================================
WasmInterpreter::HeapObjectsScope::HeapObjectsScope(
WasmInterpreter* interpreter, Handle<WasmInstanceObject> instance) {
static_assert(sizeof(data) == sizeof(HeapObjectsScopeImpl), "Size mismatch");
new (data) HeapObjectsScopeImpl(&interpreter->internals_->codemap_, instance);
}
WasmInterpreter::HeapObjectsScope::~HeapObjectsScope() {
reinterpret_cast<HeapObjectsScopeImpl*>(data)->~HeapObjectsScopeImpl();
}
#undef TRACE
#undef FOREACH_INTERNAL_OPCODE
#undef WASM_CTYPES
#undef FOREACH_SIMPLE_BINOP
#undef FOREACH_OTHER_BINOP
#undef FOREACH_OTHER_UNOP
} // namespace wasm
} // namespace internal
} // namespace v8
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