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9bdabfd649
v8/src/wasm/wasm-interpreter.cc
Clemens Hammacher 9bdabfd649 [wasm] [interpreter] Fix stack transfer to loop labels 
When branching to a loop header, we were trying to copy over {arity}
values from the value stack. This is correct for block labels, but not
for loops. When branching back to a loop header, no values need to be
transferred.

R=ahaas@chromium.org
BUG=chromium:715454

Change-Id: I90d806de63d039abf8dcac1abec057860c8f69ca
Reviewed-on: https://chromium-review.googlesource.com/488146
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44949}
2017-04-27 16:04:47 +00:00

2612 lines
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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/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/wasm-external-refs.h"
#include "src/wasm/wasm-limits.h"
#include "src/wasm/wasm-module.h"
#include "src/wasm/wasm-objects.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)
#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, float) \
V(F32Neg, float) \
V(F32Ceil, float) \
V(F32Floor, float) \
V(F32Trunc, float) \
V(F32NearestInt, float) \
V(F64Abs, double) \
V(F64Neg, double) \
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 {
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 float ExecuteF32CopySign(float a, float b, TrapReason* trap) {
return copysignf(a, b);
}
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 double ExecuteF64CopySign(double a, double b, TrapReason* trap) {
return copysign(a, b);
}
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 float ExecuteF32Abs(float a, TrapReason* trap) {
return bit_cast<float>(bit_cast<uint32_t>(a) & 0x7fffffff);
}
inline float ExecuteF32Neg(float a, TrapReason* trap) {
return bit_cast<float>(bit_cast<uint32_t>(a) ^ 0x80000000);
}
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 double ExecuteF64Abs(double a, TrapReason* trap) {
return bit_cast<double>(bit_cast<uint64_t>(a) & 0x7fffffffffffffff);
}
inline double ExecuteF64Neg(double a, TrapReason* trap) {
return bit_cast<double>(bit_cast<uint64_t>(a) ^ 0x8000000000000000);
}
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 float ExecuteF32ReinterpretI32(int32_t a, TrapReason* trap) {
return bit_cast<float>(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 double ExecuteF64ReinterpretI64(int64_t a, TrapReason* trap) {
return bit_cast<double>(a);
}
inline int32_t ExecuteI32ReinterpretF32(WasmVal a) {
return a.to_unchecked<int32_t>();
}
inline int64_t ExecuteI64ReinterpretF64(WasmVal a) {
return a.to_unchecked<int64_t>();
}
inline int32_t ExecuteGrowMemory(uint32_t delta_pages,
MaybeHandle<WasmInstanceObject> instance_obj,
WasmInstance* instance) {
DCHECK_EQ(0, instance->mem_size % WasmModule::kPageSize);
uint32_t old_pages = instance->mem_size / WasmModule::kPageSize;
// If an instance is set, execute GrowMemory on the instance. This will also
// update the WasmInstance struct used here.
if (!instance_obj.is_null()) {
Isolate* isolate = instance_obj.ToHandleChecked()->GetIsolate();
int32_t ret = WasmInstanceObject::GrowMemory(
isolate, instance_obj.ToHandleChecked(), delta_pages);
// Some sanity checks.
DCHECK_EQ(ret == -1 ? old_pages : old_pages + delta_pages,
instance->mem_size / WasmModule::kPageSize);
DCHECK(ret == -1 || static_cast<uint32_t>(ret) == old_pages);
return ret;
}
// TODO(ahaas): Move memory allocation to wasm-module.cc for better
// encapsulation.
if (delta_pages > FLAG_wasm_max_mem_pages ||
delta_pages > instance->module->max_mem_pages) {
return -1;
}
uint32_t new_pages = old_pages + delta_pages;
if (new_pages > FLAG_wasm_max_mem_pages ||
new_pages > instance->module->max_mem_pages) {
return -1;
}
byte* new_mem_start;
if (instance->mem_size == 0) {
// TODO(gdeepti): Fix bounds check to take into account size of memtype.
new_mem_start = static_cast<byte*>(
calloc(new_pages * WasmModule::kPageSize, sizeof(byte)));
if (!new_mem_start) return -1;
} else {
DCHECK_NOT_NULL(instance->mem_start);
if (EnableGuardRegions()) {
v8::base::OS::Unprotect(instance->mem_start,
new_pages * WasmModule::kPageSize);
new_mem_start = instance->mem_start;
} else {
new_mem_start = static_cast<byte*>(
realloc(instance->mem_start, new_pages * WasmModule::kPageSize));
if (!new_mem_start) return -1;
}
// Zero initializing uninitialized memory from realloc
memset(new_mem_start + old_pages * WasmModule::kPageSize, 0,
delta_pages * WasmModule::kPageSize);
}
instance->mem_start = new_mem_start;
instance->mem_size = new_pages * WasmModule::kPageSize;
return static_cast<int32_t>(old_pages);
}
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());
int mask = RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
for (RelocIterator it(*js_wrapper, mask); !it.done(); it.next()) {
HeapObject* obj = it.rinfo()->target_object();
if (!obj->IsCallable()) continue;
#ifdef DEBUG
// There should only be this one reference to a callable object.
for (it.next(); !it.done(); it.next()) {
HeapObject* other = it.rinfo()->target_object();
DCHECK(!other->IsCallable());
}
#endif
return handle(obj, isolate);
}
// If we did not find a callable object, then there must be a reference to
// the WasmThrowTypeError runtime function.
// TODO(clemensh): Check that this is the case.
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;
const uint32_t arity;
// TODO(clemensh): Fix ZoneAllocator and make this ZoneVector<const Ref>.
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;
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.push_back({code->orig_start, func_label, nullptr});
for (BytecodeIterator i(code->orig_start, code->orig_end, &code->locals);
i.has_next(); i.next()) {
WasmOpcode opcode = i.current();
auto stack_effect =
StackEffect(module, code->function->sig, i.pc(), i.end());
TRACE("@%u: control %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: {
BlockTypeOperand<false> operand(&i, i.pc());
TRACE("control @%u: Block, arity %d\n", i.pc_offset(), operand.arity);
CLabel* label =
CLabel::New(&control_transfer_zone, stack_height, operand.arity);
control_stack.push_back({i.pc(), label, nullptr});
break;
}
case kExprLoop: {
TRACE("control @%u: Loop\n", i.pc_offset());
// Arity is always 0 for loop labels.
CLabel* label = CLabel::New(&control_transfer_zone, stack_height, 0);
control_stack.push_back({i.pc(), label, nullptr});
label->Bind(i.pc());
break;
}
case kExprIf: {
TRACE("control @%u: If\n", i.pc_offset());
BlockTypeOperand<false> operand(&i, i.pc());
CLabel* end_label =
CLabel::New(&control_transfer_zone, stack_height, operand.arity);
CLabel* else_label =
CLabel::New(&control_transfer_zone, stack_height, 0);
control_stack.push_back({i.pc(), end_label, else_label});
else_label->Ref(i.pc(), stack_height);
break;
}
case kExprElse: {
Control* c = &control_stack.back();
TRACE("control @%u: Else\n", i.pc_offset());
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->end_label->arity;
control_stack.pop_back();
break;
}
case kExprBr: {
BreakDepthOperand<false> 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];
c->end_label->Ref(i.pc(), stack_height);
break;
}
case kExprBrIf: {
BreakDepthOperand<false> 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];
c->end_label->Ref(i.pc(), stack_height);
break;
}
case kExprBrTable: {
BranchTableOperand<false> operand(&i, i.pc());
BranchTableIterator<false> iterator(&i, operand);
TRACE("control @%u: BrTable[count=%u]\n", i.pc_offset(),
operand.table_count);
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;
}
}
}
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_;
// Global handle to the wasm instance.
Handle<WasmInstanceObject> instance_;
// Global handle to array of unwrapped imports.
Handle<FixedArray> imported_functions_;
// Map from WASM_TO_JS wrappers to unwrapped imports (indexes into
// imported_functions_).
IdentityMap<int, ZoneAllocationPolicy> unwrapped_imports_;
public:
CodeMap(Isolate* isolate, const WasmModule* module,
const uint8_t* module_start, Zone* zone)
: zone_(zone),
module_(module),
interpreter_code_(zone),
unwrapped_imports_(isolate->heap(), ZoneAllocationPolicy(zone)) {
if (module == nullptr) return;
interpreter_code_.reserve(module->functions.size());
for (const WasmFunction& function : module->functions) {
if (function.imported) {
DCHECK_EQ(function.code_start_offset, function.code_end_offset);
AddFunction(&function, nullptr, nullptr);
} else {
const byte* code_start = module_start + function.code_start_offset;
const byte* code_end = module_start + function.code_end_offset;
AddFunction(&function, code_start, code_end);
}
}
}
~CodeMap() {
// Destroy the global handles.
// Cast the location, not the handle, because the handle cast might access
// the object behind the handle.
GlobalHandles::Destroy(reinterpret_cast<Object**>(instance_.location()));
GlobalHandles::Destroy(
reinterpret_cast<Object**>(imported_functions_.location()));
}
const WasmModule* module() const { return module_; }
bool has_instance() const { return !instance_.is_null(); }
Handle<WasmInstanceObject> instance() const {
DCHECK(has_instance());
return instance_;
}
MaybeHandle<WasmInstanceObject> maybe_instance() const {
return has_instance() ? instance_ : MaybeHandle<WasmInstanceObject>();
}
void SetInstanceObject(WasmInstanceObject* instance) {
// Only set the instance once (otherwise we have to destroy the global
// handle first).
DCHECK(instance_.is_null());
DCHECK_EQ(instance->module(), module_);
instance_ = instance->GetIsolate()->global_handles()->Create(instance);
}
Code* GetImportedFunction(uint32_t function_index) {
DCHECK(!instance_.is_null());
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);
}
// Returns a callable object if the imported function has a JS-compatible
// signature, or a null handle otherwise.
Handle<HeapObject> GetCallableObjectForJSImport(Isolate* isolate,
Handle<Code> code) {
DCHECK_EQ(Code::WASM_TO_JS_FUNCTION, code->kind());
int* unwrapped_index = unwrapped_imports_.Find(code);
if (unwrapped_index) {
return handle(
HeapObject::cast(imported_functions_->get(*unwrapped_index)),
isolate);
}
Handle<HeapObject> called_obj = UnwrapWasmToJSWrapper(isolate, code);
if (!called_obj.is_null()) {
// Cache the unwrapped callable object.
if (imported_functions_.is_null()) {
// This is the first call to an imported function. Allocate the
// FixedArray to cache unwrapped objects.
constexpr int kInitialCacheSize = 8;
Handle<FixedArray> new_imported_functions =
isolate->factory()->NewFixedArray(kInitialCacheSize, TENURED);
// First entry: Number of occupied slots.
new_imported_functions->set(0, Smi::kZero);
imported_functions_ =
isolate->global_handles()->Create(*new_imported_functions);
}
int this_idx = Smi::cast(imported_functions_->get(0))->value() + 1;
if (this_idx == imported_functions_->length()) {
Handle<FixedArray> new_imported_functions =
isolate->factory()->CopyFixedArrayAndGrow(imported_functions_,
this_idx / 2, TENURED);
// Update the existing global handle:
*imported_functions_.location() = *new_imported_functions;
}
DCHECK_GT(imported_functions_->length(), this_idx);
DCHECK(imported_functions_->get(this_idx)->IsUndefined(isolate));
imported_functions_->set(0, Smi::FromInt(this_idx));
imported_functions_->set(this_idx, *called_obj);
unwrapped_imports_.Set(code, this_idx);
}
return called_obj;
}
};
Handle<Object> WasmValToNumber(Factory* factory, WasmVal 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();
return Handle<Object>::null();
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
WasmVal ToWebAssemblyValue(Isolate* isolate, Handle<Object> value,
wasm::ValueType type) {
switch (type) {
case kWasmI32: {
MaybeHandle<Object> maybe_i32 = Object::ToInt32(isolate, value);
// TODO(clemensh): Handle failure here (unwind).
int32_t value;
CHECK(maybe_i32.ToHandleChecked()->ToInt32(&value));
return WasmVal(value);
}
case kWasmI64:
// If the signature contains i64, a type error was thrown before.
UNREACHABLE();
case kWasmF32: {
MaybeHandle<Object> maybe_number = Object::ToNumber(value);
// TODO(clemensh): Handle failure here (unwind).
return WasmVal(
static_cast<float>(maybe_number.ToHandleChecked()->Number()));
}
case kWasmF64: {
MaybeHandle<Object> maybe_number = Object::ToNumber(value);
// TODO(clemensh): Handle failure here (unwind).
return WasmVal(maybe_number.ToHandleChecked()->Number());
}
default:
// TODO(wasm): Handle simd.
UNIMPLEMENTED();
return WasmVal();
}
}
// 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, WasmInstance* instance)
: codemap_(codemap),
instance_(instance),
zone_(zone),
frames_(zone),
activations_(zone) {}
//==========================================================================
// Implementation of public interface for WasmInterpreter::Thread.
//==========================================================================
WasmInterpreter::State state() { return state_; }
void InitFrame(const WasmFunction* function, WasmVal* 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());
}
WasmVal GetReturnValue(uint32_t index) {
if (state_ == WasmInterpreter::TRAPPED) return WasmVal(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);
}
WasmVal GetStackValue(sp_t index) {
DCHECK_GT(StackHeight(), index);
return stack_start_[index];
}
void SetStackValue(sp_t index, WasmVal 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 true).
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_;
WasmInstance* instance_;
Zone* zone_;
WasmVal* stack_start_ = nullptr; // Start of allocated stack space.
WasmVal* stack_limit_ = nullptr; // End of allocated stack space.
WasmVal* 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() { return codemap_; }
WasmInstance* instance() { return instance_; }
const WasmModule* module() { return instance_->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) {
WasmVal val;
switch (p) {
#define CASE_TYPE(wasm, ctype) \
case kWasm##wasm: \
val = WasmVal(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<false> operand(decoder, code->at(pc));
return pc + 1 + operand.length;
}
case kExprCallIndirect: {
CallIndirectOperand<false> operand(decoder, code->at(pc));
return pc + 1 + operand.length;
}
default:
UNREACHABLE();
return 0;
}
}
bool DoReturn(Decoder* decoder, InterpreterCode** code, pc_t* pc, pc_t* limit,
size_t arity) {
DCHECK_GT(frames_.size(), 0);
WasmVal* 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(WasmVal* 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) memcpy(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) {
MemoryAccessOperand<false> operand(decoder, code->at(pc), sizeof(ctype));
uint32_t index = Pop().to<uint32_t>();
if (!BoundsCheck<mtype>(instance()->mem_size, operand.offset, index)) {
DoTrap(kTrapMemOutOfBounds, pc);
return false;
}
byte* addr = instance()->mem_start + operand.offset + index;
WasmVal result(static_cast<ctype>(ReadLittleEndianValue<mtype>(addr)));
Push(result);
len = 1 + operand.length;
return true;
}
template <typename ctype, typename mtype>
bool ExecuteStore(Decoder* decoder, InterpreterCode* code, pc_t pc,
int& len) {
MemoryAccessOperand<false> operand(decoder, code->at(pc), sizeof(ctype));
WasmVal val = Pop();
uint32_t index = Pop().to<uint32_t>();
if (!BoundsCheck<mtype>(instance()->mem_size, operand.offset, index)) {
DoTrap(kTrapMemOutOfBounds, pc);
return false;
}
byte* addr = instance()->mem_start + operand.offset + index;
WriteLittleEndianValue<mtype>(addr, static_cast<mtype>(val.to<ctype>()));
len = 1 + operand.length;
if (std::is_same<float, ctype>::value) {
possible_nondeterminism_ |= std::isnan(val.to<float>());
} else if (std::is_same<double, ctype>::value) {
possible_nondeterminism_ |= std::isnan(val.to<double>());
}
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<false> operand(&decoder, code->at(pc));
len = 1 + operand.length;
break;
}
case kExprLoop: {
BlockTypeOperand<false> operand(&decoder, code->at(pc));
len = 1 + operand.length;
break;
}
case kExprIf: {
BlockTypeOperand<false> operand(&decoder, code->at(pc));
WasmVal 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: {
WasmVal cond = Pop();
WasmVal fval = Pop();
WasmVal tval = Pop();
Push(cond.to<int32_t>() != 0 ? tval : fval);
break;
}
case kExprBr: {
BreakDepthOperand<false> operand(&decoder, code->at(pc));
len = DoBreak(code, pc, operand.depth);
TRACE(" br => @%zu\n", pc + len);
break;
}
case kExprBrIf: {
BreakDepthOperand<false> operand(&decoder, code->at(pc));
WasmVal 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<false> operand(&decoder, code->at(pc));
BranchTableIterator<false> 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<false> operand(&decoder, code->at(pc));
Push(WasmVal(operand.value));
len = 1 + operand.length;
break;
}
case kExprI64Const: {
ImmI64Operand<false> operand(&decoder, code->at(pc));
Push(WasmVal(operand.value));
len = 1 + operand.length;
break;
}
case kExprF32Const: {
ImmF32Operand<false> operand(&decoder, code->at(pc));
Push(WasmVal(operand.value));
len = 1 + operand.length;
break;
}
case kExprF64Const: {
ImmF64Operand<false> operand(&decoder, code->at(pc));
Push(WasmVal(operand.value));
len = 1 + operand.length;
break;
}
case kExprGetLocal: {
LocalIndexOperand<false> operand(&decoder, code->at(pc));
Push(GetStackValue(frames_.back().sp + operand.index));
len = 1 + operand.length;
break;
}
case kExprSetLocal: {
LocalIndexOperand<false> operand(&decoder, code->at(pc));
WasmVal val = Pop();
SetStackValue(frames_.back().sp + operand.index, val);
len = 1 + operand.length;
break;
}
case kExprTeeLocal: {
LocalIndexOperand<false> operand(&decoder, code->at(pc));
WasmVal val = Pop();
SetStackValue(frames_.back().sp + operand.index, val);
Push(val);
len = 1 + operand.length;
break;
}
case kExprDrop: {
Pop();
break;
}
case kExprCallFunction: {
CallFunctionOperand<false> 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<false> 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<false> operand(&decoder, code->at(pc));
const WasmGlobal* global = &module()->globals[operand.index];
byte* ptr = instance()->globals_start + global->offset;
WasmVal val;
switch (global->type) {
#define CASE_TYPE(wasm, ctype) \
case kWasm##wasm: \
val = WasmVal(*reinterpret_cast<ctype*>(ptr)); \
break;
WASM_CTYPES(CASE_TYPE)
#undef CASE_TYPE
default:
UNREACHABLE();
}
Push(val);
len = 1 + operand.length;
break;
}
case kExprSetGlobal: {
GlobalIndexOperand<false> operand(&decoder, code->at(pc));
const WasmGlobal* global = &module()->globals[operand.index];
byte* ptr = instance()->globals_start + global->offset;
WasmVal 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) \
case kExpr##name: { \
if (!ExecuteLoad<ctype, mtype>(&decoder, code, pc, len)) return; \
break; \
}
LOAD_CASE(I32LoadMem8S, int32_t, int8_t);
LOAD_CASE(I32LoadMem8U, int32_t, uint8_t);
LOAD_CASE(I32LoadMem16S, int32_t, int16_t);
LOAD_CASE(I32LoadMem16U, int32_t, uint16_t);
LOAD_CASE(I64LoadMem8S, int64_t, int8_t);
LOAD_CASE(I64LoadMem8U, int64_t, uint8_t);
LOAD_CASE(I64LoadMem16S, int64_t, int16_t);
LOAD_CASE(I64LoadMem16U, int64_t, uint16_t);
LOAD_CASE(I64LoadMem32S, int64_t, int32_t);
LOAD_CASE(I64LoadMem32U, int64_t, uint32_t);
LOAD_CASE(I32LoadMem, int32_t, int32_t);
LOAD_CASE(I64LoadMem, int64_t, int64_t);
LOAD_CASE(F32LoadMem, float, float);
LOAD_CASE(F64LoadMem, double, double);
#undef LOAD_CASE
#define STORE_CASE(name, ctype, mtype) \
case kExpr##name: { \
if (!ExecuteStore<ctype, mtype>(&decoder, code, pc, len)) return; \
break; \
}
STORE_CASE(I32StoreMem8, int32_t, int8_t);
STORE_CASE(I32StoreMem16, int32_t, int16_t);
STORE_CASE(I64StoreMem8, int64_t, int8_t);
STORE_CASE(I64StoreMem16, int64_t, int16_t);
STORE_CASE(I64StoreMem32, int64_t, int32_t);
STORE_CASE(I32StoreMem, int32_t, int32_t);
STORE_CASE(I64StoreMem, int64_t, int64_t);
STORE_CASE(F32StoreMem, float, float);
STORE_CASE(F64StoreMem, double, double);
#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>(instance()->mem_size, 0, index)) { \
result = defval; \
} else { \
byte* addr = instance()->mem_start + index; \
/* TODO(titzer): alignment for asmjs load mem? */ \
result = static_cast<ctype>(*reinterpret_cast<mtype*>(addr)); \
} \
Push(WasmVal(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: { \
WasmVal val = Pop(); \
uint32_t index = Pop().to<uint32_t>(); \
if (BoundsCheck<mtype>(instance()->mem_size, 0, index)) { \
byte* addr = instance()->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<false> operand(&decoder, code->at(pc));
uint32_t delta_pages = Pop().to<uint32_t>();
Push(WasmVal(ExecuteGrowMemory(
delta_pages, codemap_->maybe_instance(), instance())));
len = 1 + operand.length;
break;
}
case kExprMemorySize: {
MemoryIndexOperand<false> operand(&decoder, code->at(pc));
Push(WasmVal(static_cast<uint32_t>(instance()->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: {
WasmVal val = Pop();
Push(WasmVal(ExecuteI32ReinterpretF32(val)));
possible_nondeterminism_ |= std::isnan(val.to<float>());
break;
}
case kExprI64ReinterpretF64: {
WasmVal val = Pop();
Push(WasmVal(ExecuteI64ReinterpretF64(val)));
possible_nondeterminism_ |= std::isnan(val.to<double>());
break;
}
#define EXECUTE_SIMPLE_BINOP(name, ctype, op) \
case kExpr##name: { \
WasmVal rval = Pop(); \
WasmVal lval = Pop(); \
WasmVal result(lval.to<ctype>() op rval.to<ctype>()); \
Push(result); \
break; \
}
FOREACH_SIMPLE_BINOP(EXECUTE_SIMPLE_BINOP)
#undef EXECUTE_SIMPLE_BINOP
#define EXECUTE_OTHER_BINOP(name, ctype) \
case kExpr##name: { \
TrapReason trap = kTrapCount; \
volatile ctype rval = Pop().to<ctype>(); \
volatile ctype lval = Pop().to<ctype>(); \
WasmVal result(Execute##name(lval, rval, &trap)); \
if (trap != kTrapCount) return DoTrap(trap, pc); \
Push(result); \
break; \
}
FOREACH_OTHER_BINOP(EXECUTE_OTHER_BINOP)
#undef EXECUTE_OTHER_BINOP
case kExprF32CopySign: {
// Handle kExprF32CopySign separately because it may introduce
// observable non-determinism.
TrapReason trap = kTrapCount;
volatile float rval = Pop().to<float>();
volatile float lval = Pop().to<float>();
WasmVal result(ExecuteF32CopySign(lval, rval, &trap));
Push(result);
possible_nondeterminism_ |= std::isnan(rval);
break;
}
case kExprF64CopySign: {
// Handle kExprF32CopySign separately because it may introduce
// observable non-determinism.
TrapReason trap = kTrapCount;
volatile double rval = Pop().to<double>();
volatile double lval = Pop().to<double>();
WasmVal result(ExecuteF64CopySign(lval, rval, &trap));
Push(result);
possible_nondeterminism_ |= std::isnan(rval);
break;
}
#define EXECUTE_OTHER_UNOP(name, ctype) \
case kExpr##name: { \
TrapReason trap = kTrapCount; \
volatile ctype val = Pop().to<ctype>(); \
WasmVal result(Execute##name(val, &trap)); \
if (trap != kTrapCount) return DoTrap(trap, pc); \
Push(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);
}
}
state_ = WasmInterpreter::PAUSED;
break_pc_ = hit_break ? pc : kInvalidPc;
CommitPc(pc);
}
WasmVal 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;
}
WasmVal PopArity(size_t arity) {
if (arity == 0) return WasmVal();
CHECK_EQ(1, arity);
return Pop();
}
void Push(WasmVal val) {
DCHECK_NE(kWasmStmt, val.type);
DCHECK_LE(1, stack_limit_ - sp_);
*sp_++ = val;
}
void Push(WasmVal* vals, size_t arity) {
DCHECK_LE(arity, stack_limit_ - sp_);
for (WasmVal *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 new_size = Max(size_t{8}, 2 * old_size);
while (new_size < (sp_ - stack_start_) + size) {
DCHECK_GE(std::numeric_limits<decltype(new_size)>::max() / 4, new_size);
new_size *= 2;
}
WasmVal* new_stack = zone_->NewArray<WasmVal>(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 TraceStack(const char* phase, pc_t pc) {
if (FLAG_trace_wasm_interpreter) {
PrintF("%s @%zu", phase, pc);
UNIMPLEMENTED();
PrintF("\n");
}
}
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);
WasmVal 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};
}
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()) {
// TODO(wasm): Implement calling functions of other instances/modules.
UNIMPLEMENTED();
}
int target_func_idx = Smi::cast(deopt_data->get(1))->value();
DCHECK_LE(0, target_func_idx);
return {ExternalCallResult::INTERNAL,
codemap()->GetCode(target_func_idx)};
}
Handle<HeapObject> target =
codemap()->GetCallableObjectForJSImport(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);
WasmVal* wasm_args = sp_ - num_args;
for (int i = 0; i < num_args; ++i) {
args.push_back(WasmValToNumber(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;
if (signature->return_count() > 0) {
// TODO(wasm): Handle multiple returns.
DCHECK_EQ(1, signature->return_count());
Push(ToWebAssemblyValue(isolate, retval, signature->GetReturn()));
}
return {ExternalCallResult::EXTERNAL_RETURNED};
}
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()) {
// 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.
// TODO(titzer): make this faster with some kind of caching?
const WasmIndirectFunctionTable* table =
&module()->function_tables[table_index];
int function_key = table->map.Find(code->function->sig);
if (function_key < 0 ||
(function_key !=
table->map.Find(module()->signatures[sig_index]))) {
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.
// TODO(titzer): make this faster with some kind of caching?
const WasmIndirectFunctionTable* table =
&module()->function_tables[table_index];
FunctionSig* sig = module()->signatures[sig_index];
uint32_t canonical_sig_index = table->map.Find(sig);
// 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};
}
FixedArray* sig_table =
FixedArray::cast(sig_tables->get(static_cast<int>(table_index)));
if (entry_index >= static_cast<uint32_t>(sig_table->length())) {
return {ExternalCallResult::INVALID_FUNC};
}
int found_sig =
Smi::cast(sig_table->get(static_cast<int>(entry_index)))->value();
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());
FixedArray* fun_table =
FixedArray::cast(fun_tables->get(static_cast<int>(table_index)));
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();
}
WasmVal GetLocalValue(int index) const {
DCHECK_LE(0, index);
DCHECK_GT(GetLocalCount(), index);
return thread_->GetStackValue(static_cast<int>(frame()->sp) + index);
}
WasmVal 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);
}
} // 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,
WasmVal* 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)));
}
WasmVal 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:
WasmInstance* instance_;
// 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 ModuleBytesEnv& env)
: instance_(env.module_env.instance),
module_bytes_(env.wire_bytes.start(), env.wire_bytes.end(), zone),
codemap_(
isolate,
env.module_env.instance ? env.module_env.instance->module : nullptr,
module_bytes_.data(), zone),
threads_(zone) {
threads_.emplace_back(zone, &codemap_, env.module_env.instance);
}
};
//============================================================================
// Implementation of the public interface of the interpreter.
//============================================================================
WasmInterpreter::WasmInterpreter(Isolate* isolate, const ModuleBytesEnv& env)
: zone_(isolate->allocator(), ZONE_NAME),
internals_(new (&zone_) WasmInterpreterInternals(isolate, &zone_, env)) {}
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;
}
void WasmInterpreter::SetInstanceObject(WasmInstanceObject* instance) {
internals_->codemap_.SetInstanceObject(instance);
}
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]);
}
size_t WasmInterpreter::GetMemorySize() {
return internals_->instance_->mem_size;
}
WasmVal WasmInterpreter::ReadMemory(size_t offset) {
UNIMPLEMENTED();
return WasmVal();
}
void WasmInterpreter::WriteMemory(size_t offset, WasmVal val) {
UNIMPLEMENTED();
}
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();
}
WasmVal InterpretedFrame::GetLocalValue(int index) const {
return ToImpl(this)->GetLocalValue(index);
}
WasmVal InterpretedFrame::GetStackValue(int index) const {
return ToImpl(this)->GetStackValue(index);
}
} // namespace wasm
} // namespace internal
} // namespace v8
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