// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/macro-assembler.h"
#include "src/objects.h"
#include "src/v8.h"
#include "src/simulator.h"
#include "src/wasm/ast-decoder.h"
#include "src/wasm/module-decoder.h"
#include "src/wasm/wasm-module.h"
#include "src/wasm/wasm-result.h"
#include "src/compiler/wasm-compiler.h"
namespace v8 {
namespace internal {
namespace wasm {
std::ostream& operator<<(std::ostream& os, const WasmModule& module) {
os << "WASM module with ";
os << (1 << module.min_mem_size_log2) << " min mem";
os << (1 << module.max_mem_size_log2) << " max mem";
if (module.functions) os << module.functions->size() << " functions";
if (module.globals) os << module.functions->size() << " globals";
if (module.data_segments) os << module.functions->size() << " data segments";
return os;
}
std::ostream& operator<<(std::ostream& os, const WasmFunction& function) {
os << "WASM function with signature ";
// TODO(titzer): factor out rendering of signatures.
if (function.sig->return_count() == 0) os << "v";
for (size_t i = 0; i < function.sig->return_count(); i++) {
os << WasmOpcodes::ShortNameOf(function.sig->GetReturn(i));
}
os << "_";
if (function.sig->parameter_count() == 0) os << "v";
for (size_t i = 0; i < function.sig->parameter_count(); i++) {
os << WasmOpcodes::ShortNameOf(function.sig->GetParam(i));
}
os << " locals: ";
if (function.local_int32_count)
os << function.local_int32_count << " int32s ";
if (function.local_int64_count)
os << function.local_int64_count << " int64s ";
if (function.local_float32_count)
os << function.local_float32_count << " float32s ";
if (function.local_float64_count)
os << function.local_float64_count << " float64s ";
os << " code bytes: "
<< (function.code_end_offset - function.code_start_offset);
return os;
}
// A helper class for compiling multiple wasm functions that offers
// placeholder code objects for calling functions that are not yet compiled.
class WasmLinker {
public:
WasmLinker(Isolate* isolate, size_t size)
: isolate_(isolate), placeholder_code_(size), function_code_(size) {}
// Get the code object for a function, allocating a placeholder if it has
// not yet been compiled.
Handle<Code> GetFunctionCode(uint32_t index) {
DCHECK(index < function_code_.size());
if (function_code_[index].is_null()) {
// Create a placeholder code object and encode the corresponding index in
// the {constant_pool_offset} field of the code object.
// TODO(titzer): placeholder code objects are somewhat dangerous.
Handle<Code> self(nullptr, isolate_);
byte buffer[] = {0, 0, 0, 0, 0, 0, 0, 0}; // fake instructions.
CodeDesc desc = {buffer, 8, 8, 0, 0, nullptr};
Handle<Code> code = isolate_->factory()->NewCode(
desc, Code::KindField::encode(Code::WASM_FUNCTION), self);
code->set_constant_pool_offset(index + kPlaceholderMarker);
placeholder_code_[index] = code;
function_code_[index] = code;
}
return function_code_[index];
}
void Finish(uint32_t index, Handle<Code> code) {
DCHECK(index < function_code_.size());
function_code_[index] = code;
}
void Link(Handle<FixedArray> function_table,
std::vector<uint16_t>* functions) {
for (size_t i = 0; i < function_code_.size(); i++) {
LinkFunction(function_code_[i]);
}
if (functions && !function_table.is_null()) {
int table_size = static_cast<int>(functions->size());
DCHECK_EQ(function_table->length(), table_size * 2);
for (int i = 0; i < table_size; i++) {
function_table->set(i + table_size, *function_code_[functions->at(i)]);
}
}
}
private:
static const int kPlaceholderMarker = 1000000000;
Isolate* isolate_;
std::vector<Handle<Code>> placeholder_code_;
std::vector<Handle<Code>> function_code_;
void LinkFunction(Handle<Code> code) {
bool modified = false;
int mode_mask = RelocInfo::kCodeTargetMask;
AllowDeferredHandleDereference embedding_raw_address;
for (RelocIterator it(*code, mode_mask); !it.done(); it.next()) {
RelocInfo::Mode mode = it.rinfo()->rmode();
if (RelocInfo::IsCodeTarget(mode)) {
Code* target =
Code::GetCodeFromTargetAddress(it.rinfo()->target_address());
if (target->kind() == Code::WASM_FUNCTION &&
target->constant_pool_offset() >= kPlaceholderMarker) {
// Patch direct calls to placeholder code objects.
uint32_t index = target->constant_pool_offset() - kPlaceholderMarker;
CHECK(index < function_code_.size());
Handle<Code> new_target = function_code_[index];
if (target != *new_target) {
CHECK_EQ(*placeholder_code_[index], target);
it.rinfo()->set_target_address(new_target->instruction_start(),
SKIP_WRITE_BARRIER,
SKIP_ICACHE_FLUSH);
modified = true;
}
}
}
}
if (modified) {
Assembler::FlushICache(isolate_, code->instruction_start(),
code->instruction_size());
}
}
};
namespace {
// Internal constants for the layout of the module object.
const int kWasmModuleInternalFieldCount = 4;
const int kWasmModuleFunctionTable = 0;
const int kWasmModuleCodeTable = 1;
const int kWasmMemArrayBuffer = 2;
const int kWasmGlobalsArrayBuffer = 3;
size_t AllocateGlobalsOffsets(std::vector<WasmGlobal>* globals) {
uint32_t offset = 0;
if (!globals) return 0;
for (WasmGlobal& global : *globals) {
byte size = WasmOpcodes::MemSize(global.type);
offset = (offset + size - 1) & ~(size - 1); // align
global.offset = offset;
offset += size;
}
return offset;
}
void LoadDataSegments(WasmModule* module, byte* mem_addr, size_t mem_size) {
for (const WasmDataSegment& segment : *module->data_segments) {
if (!segment.init) continue;
CHECK_LT(segment.dest_addr, mem_size);
CHECK_LE(segment.source_size, mem_size);
CHECK_LE(segment.dest_addr + segment.source_size, mem_size);
byte* addr = mem_addr + segment.dest_addr;
memcpy(addr, module->module_start + segment.source_offset,
segment.source_size);
}
}
Handle<FixedArray> BuildFunctionTable(Isolate* isolate, WasmModule* module) {
if (!module->function_table || module->function_table->size() == 0) {
return Handle<FixedArray>::null();
}
int table_size = static_cast<int>(module->function_table->size());
Handle<FixedArray> fixed = isolate->factory()->NewFixedArray(2 * table_size);
for (int i = 0; i < table_size; i++) {
WasmFunction* function =
&module->functions->at(module->function_table->at(i));
fixed->set(i, Smi::FromInt(function->sig_index));
}
return fixed;
}
Handle<JSArrayBuffer> NewArrayBuffer(Isolate* isolate, int size,
byte** backing_store) {
void* memory = isolate->array_buffer_allocator()->Allocate(size);
if (!memory) return Handle<JSArrayBuffer>::null();
*backing_store = reinterpret_cast<byte*>(memory);
#if DEBUG
// Double check the API allocator actually zero-initialized the memory.
for (int i = 0; i < size; i++) {
DCHECK_EQ(0, (*backing_store)[i]);
}
#endif
Handle<JSArrayBuffer> buffer = isolate->factory()->NewJSArrayBuffer();
JSArrayBuffer::Setup(buffer, isolate, false, memory, size);
buffer->set_is_neuterable(false);
return buffer;
}
} // namespace
WasmModule::WasmModule()
: globals(nullptr),
signatures(nullptr),
functions(nullptr),
data_segments(nullptr),
function_table(nullptr) {}
WasmModule::~WasmModule() {
if (globals) delete globals;
if (signatures) delete signatures;
if (functions) delete functions;
if (data_segments) delete data_segments;
if (function_table) delete function_table;
}
// Instantiates a wasm module as a JSObject.
// * allocates a backing store of {mem_size} bytes.
// * installs a named property "memory" for that buffer if exported
// * installs named properties on the object for exported functions
// * compiles wasm code to machine code
MaybeHandle<JSObject> WasmModule::Instantiate(Isolate* isolate,
Handle<JSObject> ffi,
Handle<JSArrayBuffer> memory) {
this->shared_isolate = isolate; // TODO(titzer): have a real shared isolate.
ErrorThrower thrower(isolate, "WasmModule::Instantiate()");
Factory* factory = isolate->factory();
// Memory is bigger than maximum supported size.
if (memory.is_null() && min_mem_size_log2 > kMaxMemSize) {
thrower.Error("Out of memory: wasm memory too large");
return MaybeHandle<JSObject>();
}
Handle<Map> map = factory->NewMap(
JS_OBJECT_TYPE,
JSObject::kHeaderSize + kWasmModuleInternalFieldCount * kPointerSize);
//-------------------------------------------------------------------------
// Allocate the module object.
//-------------------------------------------------------------------------
Handle<JSObject> module = factory->NewJSObjectFromMap(map, TENURED);
Handle<FixedArray> code_table =
factory->NewFixedArray(static_cast<int>(functions->size()), TENURED);
//-------------------------------------------------------------------------
// Allocate the linear memory.
//-------------------------------------------------------------------------
uint32_t mem_size = 1 << min_mem_size_log2;
byte* mem_addr = nullptr;
Handle<JSArrayBuffer> mem_buffer;
if (!memory.is_null()) {
memory->set_is_neuterable(false);
mem_addr = reinterpret_cast<byte*>(memory->backing_store());
mem_size = memory->byte_length()->Number();
mem_buffer = memory;
} else {
mem_buffer = NewArrayBuffer(isolate, mem_size, &mem_addr);
if (!mem_addr) {
// Not enough space for backing store of memory
thrower.Error("Out of memory: wasm memory");
return MaybeHandle<JSObject>();
}
}
// Load initialized data segments.
LoadDataSegments(this, mem_addr, mem_size);
module->SetInternalField(kWasmMemArrayBuffer, *mem_buffer);
if (mem_export) {
// Export the memory as a named property.
Handle<String> name = factory->InternalizeUtf8String("memory");
JSObject::AddProperty(module, name, mem_buffer, READ_ONLY);
}
//-------------------------------------------------------------------------
// Allocate the globals area if necessary.
//-------------------------------------------------------------------------
size_t globals_size = AllocateGlobalsOffsets(globals);
byte* globals_addr = nullptr;
if (globals_size > 0) {
Handle<JSArrayBuffer> globals_buffer =
NewArrayBuffer(isolate, mem_size, &globals_addr);
if (!globals_addr) {
// Not enough space for backing store of globals.
thrower.Error("Out of memory: wasm globals");
return MaybeHandle<JSObject>();
}
module->SetInternalField(kWasmGlobalsArrayBuffer, *globals_buffer);
} else {
module->SetInternalField(kWasmGlobalsArrayBuffer, Smi::FromInt(0));
}
//-------------------------------------------------------------------------
// Compile all functions in the module.
//-------------------------------------------------------------------------
int index = 0;
WasmLinker linker(isolate, functions->size());
ModuleEnv module_env;
module_env.module = this;
module_env.mem_start = reinterpret_cast<uintptr_t>(mem_addr);
module_env.mem_end = reinterpret_cast<uintptr_t>(mem_addr) + mem_size;
module_env.globals_area = reinterpret_cast<uintptr_t>(globals_addr);
module_env.linker = &linker;
module_env.function_code = nullptr;
module_env.function_table = BuildFunctionTable(isolate, this);
module_env.memory = memory;
module_env.context = isolate->native_context();
module_env.asm_js = false;
// First pass: compile each function and initialize the code table.
for (const WasmFunction& func : *functions) {
if (thrower.error()) break;
const char* cstr = GetName(func.name_offset);
Handle<String> name = factory->InternalizeUtf8String(cstr);
Handle<Code> code = Handle<Code>::null();
Handle<JSFunction> function = Handle<JSFunction>::null();
if (func.external) {
// Lookup external function in FFI object.
if (!ffi.is_null()) {
MaybeHandle<Object> result = Object::GetProperty(ffi, name);
if (!result.is_null()) {
Handle<Object> obj = result.ToHandleChecked();
if (obj->IsJSFunction()) {
function = Handle<JSFunction>::cast(obj);
code = compiler::CompileWasmToJSWrapper(isolate, &module_env,
function, index);
} else {
thrower.Error("FFI function #%d:%s is not a JSFunction.", index,
cstr);
return MaybeHandle<JSObject>();
}
} else {
thrower.Error("FFI function #%d:%s not found.", index, cstr);
return MaybeHandle<JSObject>();
}
} else {
thrower.Error("FFI table is not an object.");
return MaybeHandle<JSObject>();
}
} else {
// Compile the function.
code = compiler::CompileWasmFunction(thrower, isolate, &module_env, func,
index);
if (code.is_null()) {
thrower.Error("Compilation of #%d:%s failed.", index, cstr);
return MaybeHandle<JSObject>();
}
if (func.exported) {
function = compiler::CompileJSToWasmWrapper(isolate, &module_env, name,
code, module, index);
}
}
if (!code.is_null()) {
// Install the code into the linker table.
linker.Finish(index, code);
code_table->set(index, *code);
}
if (func.exported) {
// Exported functions are installed as read-only properties on the module.
JSObject::AddProperty(module, name, function, READ_ONLY);
}
index++;
}
// Second pass: patch all direct call sites.
linker.Link(module_env.function_table, this->function_table);
module->SetInternalField(kWasmModuleFunctionTable, Smi::FromInt(0));
module->SetInternalField(kWasmModuleCodeTable, *code_table);
return module;
}
Handle<Code> ModuleEnv::GetFunctionCode(uint32_t index) {
DCHECK(IsValidFunction(index));
if (linker) return linker->GetFunctionCode(index);
if (function_code) return function_code->at(index);
return Handle<Code>::null();
}
compiler::CallDescriptor* ModuleEnv::GetCallDescriptor(Zone* zone,
uint32_t index) {
DCHECK(IsValidFunction(index));
// Always make a direct call to whatever is in the table at that location.
// A wrapper will be generated for FFI calls.
WasmFunction* function = &module->functions->at(index);
return GetWasmCallDescriptor(zone, function->sig);
}
int32_t CompileAndRunWasmModule(Isolate* isolate, const byte* module_start,
const byte* module_end, bool asm_js) {
HandleScope scope(isolate);
Zone zone;
// Decode the module, but don't verify function bodies, since we'll
// be compiling them anyway.
ModuleResult result =
DecodeWasmModule(isolate, &zone, module_start, module_end, false, false);
if (result.failed()) {
// Module verification failed. throw.
std::ostringstream str;
str << "WASM.compileRun() failed: " << result;
isolate->Throw(
*isolate->factory()->NewStringFromAsciiChecked(str.str().c_str()));
return -1;
}
int32_t retval = CompileAndRunWasmModule(isolate, result.val);
delete result.val;
return retval;
}
int32_t CompileAndRunWasmModule(Isolate* isolate, WasmModule* module) {
ErrorThrower thrower(isolate, "CompileAndRunWasmModule");
// Allocate temporary linear memory and globals.
size_t mem_size = 1 << module->min_mem_size_log2;
size_t globals_size = AllocateGlobalsOffsets(module->globals);
base::SmartArrayPointer<byte> mem_addr(new byte[mem_size]);
base::SmartArrayPointer<byte> globals_addr(new byte[globals_size]);
memset(mem_addr.get(), 0, mem_size);
memset(globals_addr.get(), 0, globals_size);
// Create module environment.
WasmLinker linker(isolate, module->functions->size());
ModuleEnv module_env;
module_env.module = module;
module_env.mem_start = reinterpret_cast<uintptr_t>(mem_addr.get());
module_env.mem_end = reinterpret_cast<uintptr_t>(mem_addr.get()) + mem_size;
module_env.globals_area = reinterpret_cast<uintptr_t>(globals_addr.get());
module_env.linker = &linker;
module_env.function_code = nullptr;
module_env.function_table = BuildFunctionTable(isolate, module);
module_env.asm_js = false;
// Load data segments.
// TODO(titzer): throw instead of crashing if segments don't fit in memory?
LoadDataSegments(module, mem_addr.get(), mem_size);
// Compile all functions.
Handle<Code> main_code = Handle<Code>::null(); // record last code.
int index = 0;
for (const WasmFunction& func : *module->functions) {
if (!func.external) {
// Compile the function and install it in the code table.
Handle<Code> code = compiler::CompileWasmFunction(
thrower, isolate, &module_env, func, index);
if (!code.is_null()) {
if (func.exported) main_code = code;
linker.Finish(index, code);
}
if (thrower.error()) return -1;
}
index++;
}
if (!main_code.is_null()) {
linker.Link(module_env.function_table, module->function_table);
#if USE_SIMULATOR && V8_TARGET_ARCH_ARM64
// Run the main code on arm64 simulator.
Simulator* simulator = Simulator::current(isolate);
Simulator::CallArgument args[] = {Simulator::CallArgument(0),
Simulator::CallArgument::End()};
return static_cast<int32_t>(simulator->CallInt64(main_code->entry(), args));
#elif USE_SIMULATOR
// Run the main code on simulator.
Simulator* simulator = Simulator::current(isolate);
return static_cast<int32_t>(
simulator->Call(main_code->entry(), 4, 0, 0, 0, 0));
#else
// Run the main code as raw machine code.
int32_t (*raw_func)() = reinterpret_cast<int32_t (*)()>(
reinterpret_cast<uintptr_t>(main_code->entry()));
return raw_func();
#endif
} else {
// No main code was found.
isolate->Throw(*isolate->factory()->NewStringFromStaticChars(
"WASM.compileRun() failed: no valid main code produced."));
}
return -1;
}
} // namespace wasm
} // namespace internal
} // namespace v8