// 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.
#ifndef V8_WASM_MODULE_H_
#define V8_WASM_MODULE_H_
#include "src/api.h"
#include "src/handles.h"
#include "src/wasm/wasm-opcodes.h"
#include "src/wasm/wasm-result.h"
namespace v8 {
namespace internal {
namespace compiler {
class CallDescriptor;
class WasmCompilationUnit;
}
namespace wasm {
const size_t kMaxModuleSize = 1024 * 1024 * 1024;
const size_t kMaxFunctionSize = 128 * 1024;
const size_t kMaxStringSize = 256;
const uint32_t kWasmMagic = 0x6d736100;
const uint32_t kWasmVersion = 0x0b;
const uint8_t kWasmFunctionTypeForm = 0x40;
// WebAssembly sections are named as strings in the binary format, but
// internally V8 uses an enum to handle them.
//
// Entries have the form F(enumerator, string).
#define FOR_EACH_WASM_SECTION_TYPE(F) \
F(Signatures, 1, "type") \
F(ImportTable, 2, "import") \
F(FunctionSignatures, 3, "function") \
F(FunctionTable, 4, "table") \
F(Memory, 5, "memory") \
F(ExportTable, 6, "export") \
F(StartFunction, 7, "start") \
F(FunctionBodies, 8, "code") \
F(DataSegments, 9, "data") \
F(Names, 10, "name") \
F(FunctionTablePad, 11, "table_pad") \
F(Globals, 0, "global") \
F(End, 0, "end")
// Contants for the above section types: {LEB128 length, characters...}.
#define WASM_SECTION_MEMORY 6, 'm', 'e', 'm', 'o', 'r', 'y'
#define WASM_SECTION_SIGNATURES 4, 't', 'y', 'p', 'e'
#define WASM_SECTION_GLOBALS 6, 'g', 'l', 'o', 'b', 'a', 'l'
#define WASM_SECTION_DATA_SEGMENTS 4, 'd', 'a', 't', 'a'
#define WASM_SECTION_FUNCTION_TABLE 5, 't', 'a', 'b', 'l', 'e'
#define WASM_SECTION_END 3, 'e', 'n', 'd'
#define WASM_SECTION_START_FUNCTION 5, 's', 't', 'a', 'r', 't'
#define WASM_SECTION_IMPORT_TABLE 6, 'i', 'm', 'p', 'o', 'r', 't'
#define WASM_SECTION_EXPORT_TABLE 6, 'e', 'x', 'p', 'o', 'r', 't'
#define WASM_SECTION_FUNCTION_SIGNATURES \
8, 'f', 'u', 'n', 'c', 't', 'i', 'o', 'n'
#define WASM_SECTION_FUNCTION_BODIES 4, 'c', 'o', 'd', 'e'
#define WASM_SECTION_NAMES 4, 'n', 'a', 'm', 'e'
#define WASM_SECTION_FUNCTION_TABLE_PAD \
9, 't', 'a', 'b', 'l', 'e', '_', 'p', 'a', 'd'
// Constants for the above section headers' size (LEB128 + characters).
#define WASM_SECTION_MEMORY_SIZE ((size_t)7)
#define WASM_SECTION_SIGNATURES_SIZE ((size_t)5)
#define WASM_SECTION_GLOBALS_SIZE ((size_t)7)
#define WASM_SECTION_DATA_SEGMENTS_SIZE ((size_t)5)
#define WASM_SECTION_FUNCTION_TABLE_SIZE ((size_t)6)
#define WASM_SECTION_END_SIZE ((size_t)4)
#define WASM_SECTION_START_FUNCTION_SIZE ((size_t)6)
#define WASM_SECTION_IMPORT_TABLE_SIZE ((size_t)7)
#define WASM_SECTION_EXPORT_TABLE_SIZE ((size_t)7)
#define WASM_SECTION_FUNCTION_SIGNATURES_SIZE ((size_t)9)
#define WASM_SECTION_FUNCTION_BODIES_SIZE ((size_t)5)
#define WASM_SECTION_NAMES_SIZE ((size_t)5)
#define WASM_SECTION_FUNCTION_TABLE_PAD_SIZE ((size_t)10)
class WasmDebugInfo;
struct WasmSection {
enum class Code : uint32_t {
#define F(enumerator, order, string) enumerator,
FOR_EACH_WASM_SECTION_TYPE(F)
#undef F
Max
};
static WasmSection::Code begin();
static WasmSection::Code end();
static WasmSection::Code next(WasmSection::Code code);
static const char* getName(Code code);
static int getOrder(Code code);
static size_t getNameLength(Code code);
static WasmSection::Code lookup(const byte* string, uint32_t length);
};
enum WasmFunctionDeclBit {
kDeclFunctionName = 0x01,
kDeclFunctionExport = 0x08
};
// Constants for fixed-size elements within a module.
static const size_t kDeclMemorySize = 3;
static const size_t kDeclDataSegmentSize = 13;
static const uint32_t kMaxReturnCount = 1;
// Static representation of a WASM function.
struct WasmFunction {
FunctionSig* sig; // signature of the function.
uint32_t func_index; // index into the function table.
uint32_t sig_index; // index into the signature table.
uint32_t name_offset; // offset in the module bytes of the name, if any.
uint32_t name_length; // length in bytes of the name.
uint32_t code_start_offset; // offset in the module bytes of code start.
uint32_t code_end_offset; // offset in the module bytes of code end.
};
// Static representation of an imported WASM function.
struct WasmImport {
FunctionSig* sig; // signature of the function.
uint32_t sig_index; // index into the signature table.
uint32_t module_name_offset; // offset in module bytes of the module name.
uint32_t module_name_length; // length in bytes of the module name.
uint32_t function_name_offset; // offset in module bytes of the import name.
uint32_t function_name_length; // length in bytes of the import name.
};
// Static representation of an exported WASM function.
struct WasmExport {
uint32_t func_index; // index into the function table.
uint32_t name_offset; // offset in module bytes of the name to export.
uint32_t name_length; // length in bytes of the exported name.
};
// Static representation of a wasm global variable.
struct WasmGlobal {
uint32_t name_offset; // offset in the module bytes of the name, if any.
uint32_t name_length; // length in bytes of the global name.
MachineType type; // type of the global.
uint32_t offset; // offset from beginning of globals area.
bool exported; // true if this global is exported.
};
// Static representation of a wasm data segment.
struct WasmDataSegment {
uint32_t dest_addr; // destination memory address of the data.
uint32_t source_offset; // start offset in the module bytes.
uint32_t source_size; // end offset in the module bytes.
bool init; // true if loaded upon instantiation.
};
enum ModuleOrigin { kWasmOrigin, kAsmJsOrigin };
// Static representation of a module.
struct WasmModule {
static const uint32_t kPageSize = 0x10000; // Page size, 64kb.
static const uint32_t kMinMemPages = 1; // Minimum memory size = 64kb
static const uint32_t kMaxMemPages = 16384; // Maximum memory size = 1gb
const byte* module_start; // starting address for the module bytes.
const byte* module_end; // end address for the module bytes.
uint32_t min_mem_pages; // minimum size of the memory in 64k pages.
uint32_t max_mem_pages; // maximum size of the memory in 64k pages.
bool mem_export; // true if the memory is exported.
bool mem_external; // true if the memory is external.
// TODO(wasm): reconcile start function index being an int with
// the fact that we index on uint32_t, so we may technically not be
// able to represent some start_function_index -es.
int start_function_index; // start function, if any.
ModuleOrigin origin; // origin of the module
std::vector<WasmGlobal> globals; // globals in this module.
uint32_t globals_size; // size of globals table.
uint32_t indirect_table_size; // size of indirect function
// table (includes padding).
std::vector<FunctionSig*> signatures; // signatures in this module.
std::vector<WasmFunction> functions; // functions in this module.
std::vector<WasmDataSegment> data_segments; // data segments in this module.
std::vector<uint16_t> function_table; // function table.
std::vector<WasmImport> import_table; // import table.
std::vector<WasmExport> export_table; // export table.
// We store the semaphore here to extend its lifetime. In <libc-2.21, which we
// use on the try bots, semaphore::Wait() can return while some compilation
// tasks are still executing semaphore::Signal(). If the semaphore is cleaned
// up right after semaphore::Wait() returns, then this can cause an
// invalid-semaphore error in the compilation tasks.
// TODO(wasm): Move this semaphore back to CompileInParallel when the try bots
// switch to libc-2.21 or higher.
base::SmartPointer<base::Semaphore> pending_tasks;
WasmModule() : WasmModule(nullptr) {}
explicit WasmModule(byte* module_start);
// Get a string stored in the module bytes representing a name.
WasmName GetName(uint32_t offset, uint32_t length) const {
if (length == 0) return {"<?>", 3}; // no name.
CHECK(BoundsCheck(offset, offset + length));
DCHECK_GE(static_cast<int>(length), 0);
return {reinterpret_cast<const char*>(module_start + offset),
static_cast<int>(length)};
}
// Get a string stored in the module bytes representing a function name.
WasmName GetName(WasmFunction* function) const {
return GetName(function->name_offset, function->name_length);
}
// Get a string stored in the module bytes representing a name.
WasmName GetNameOrNull(uint32_t offset, uint32_t length) const {
if (offset == 0 && length == 0) return {NULL, 0}; // no name.
CHECK(BoundsCheck(offset, offset + length));
DCHECK_GE(static_cast<int>(length), 0);
return {reinterpret_cast<const char*>(module_start + offset),
static_cast<int>(length)};
}
// Get a string stored in the module bytes representing a function name.
WasmName GetNameOrNull(const WasmFunction* function) const {
return GetNameOrNull(function->name_offset, function->name_length);
}
// Checks the given offset range is contained within the module bytes.
bool BoundsCheck(uint32_t start, uint32_t end) const {
size_t size = module_end - module_start;
return start <= size && end <= size;
}
// Creates a new instantiation of the module in the given isolate.
static MaybeHandle<JSObject> Instantiate(Isolate* isolate,
Handle<FixedArray> compiled_module,
Handle<JSReceiver> ffi,
Handle<JSArrayBuffer> memory);
MaybeHandle<FixedArray> CompileFunctions(Isolate* isolate,
ErrorThrower* thrower) const;
uint32_t FunctionTableSize() const {
if (indirect_table_size > 0) {
return indirect_table_size;
}
DCHECK_LE(function_table.size(), UINT32_MAX);
return static_cast<uint32_t>(function_table.size());
}
};
// An instantiated WASM module, including memory, function table, etc.
struct WasmModuleInstance {
const WasmModule* module; // static representation of the module.
// -- Heap allocated --------------------------------------------------------
Handle<JSObject> js_object; // JavaScript module object.
Handle<Context> context; // JavaScript native context.
Handle<JSArrayBuffer> mem_buffer; // Handle to array buffer of memory.
Handle<JSArrayBuffer> globals_buffer; // Handle to array buffer of globals.
Handle<FixedArray> function_table; // indirect function table.
std::vector<Handle<Code>> function_code; // code objects for each function.
std::vector<Handle<Code>> import_code; // code objects for each import.
// -- raw memory ------------------------------------------------------------
byte* mem_start; // start of linear memory.
uint32_t mem_size; // size of the linear memory.
// -- raw globals -----------------------------------------------------------
byte* globals_start; // start of the globals area.
explicit WasmModuleInstance(const WasmModule* m)
: module(m),
function_code(m->functions.size()),
import_code(m->import_table.size()),
mem_start(nullptr),
mem_size(0),
globals_start(nullptr) {}
};
// Interface provided to the decoder/graph builder which contains only
// minimal information about the globals, functions, and function tables.
struct ModuleEnv {
const WasmModule* module;
WasmModuleInstance* instance;
ModuleOrigin origin;
// TODO(mtrofin): remove this once we introduce WASM_DIRECT_CALL
// reloc infos.
std::vector<Handle<Code>> placeholders;
bool IsValidGlobal(uint32_t index) {
return module && index < module->globals.size();
}
bool IsValidFunction(uint32_t index) const {
return module && index < module->functions.size();
}
bool IsValidSignature(uint32_t index) {
return module && index < module->signatures.size();
}
bool IsValidImport(uint32_t index) {
return module && index < module->import_table.size();
}
MachineType GetGlobalType(uint32_t index) {
DCHECK(IsValidGlobal(index));
return module->globals[index].type;
}
FunctionSig* GetFunctionSignature(uint32_t index) {
DCHECK(IsValidFunction(index));
return module->functions[index].sig;
}
FunctionSig* GetImportSignature(uint32_t index) {
DCHECK(IsValidImport(index));
return module->import_table[index].sig;
}
FunctionSig* GetSignature(uint32_t index) {
DCHECK(IsValidSignature(index));
return module->signatures[index];
}
uint32_t FunctionTableSize() const {
return module->FunctionTableSize();
}
bool asm_js() { return origin == kAsmJsOrigin; }
Handle<Code> GetCodeOrPlaceholder(uint32_t index) const;
Handle<Code> GetImportCode(uint32_t index);
static compiler::CallDescriptor* GetWasmCallDescriptor(Zone* zone,
FunctionSig* sig);
static compiler::CallDescriptor* GetI32WasmCallDescriptor(
Zone* zone, compiler::CallDescriptor* descriptor);
compiler::CallDescriptor* GetCallDescriptor(Zone* zone, uint32_t index);
};
// A helper for printing out the names of functions.
struct WasmFunctionName {
const WasmFunction* function_;
const WasmModule* module_;
WasmFunctionName(const WasmFunction* function, const ModuleEnv* menv)
: function_(function), module_(menv ? menv->module : nullptr) {}
};
std::ostream& operator<<(std::ostream& os, const WasmModule& module);
std::ostream& operator<<(std::ostream& os, const WasmFunction& function);
std::ostream& operator<<(std::ostream& os, const WasmFunctionName& name);
typedef Result<const WasmModule*> ModuleResult;
typedef Result<WasmFunction*> FunctionResult;
typedef std::vector<std::pair<int, int>> FunctionOffsets;
typedef Result<FunctionOffsets> FunctionOffsetsResult;
// Extract a function name from the given wasm object.
// Returns "<WASM UNNAMED>" if the function is unnamed or the name is not a
// valid UTF-8 string.
Handle<String> GetWasmFunctionName(Isolate* isolate, Handle<Object> wasm,
uint32_t func_index);
// Extract a function name from the given wasm object.
// Returns a null handle if the function is unnamed or the name is not a valid
// UTF-8 string.
Handle<Object> GetWasmFunctionNameOrNull(Isolate* isolate, Handle<Object> wasm,
uint32_t func_index);
// Return the binary source bytes of a wasm module.
SeqOneByteString* GetWasmBytes(JSObject* wasm);
// Get the debug info associated with the given wasm object.
// If no debug info exists yet, it is created automatically.
Handle<WasmDebugInfo> GetDebugInfo(Handle<JSObject> wasm);
// Return the number of functions in the given wasm object.
int GetNumberOfFunctions(JSObject* wasm);
// Create and export JSFunction
Handle<JSFunction> WrapExportCodeAsJSFunction(Isolate* isolate,
Handle<Code> export_code,
Handle<String> name, int arity,
Handle<JSObject> module_instance);
// Check whether the given object is a wasm object.
// This checks the number and type of internal fields, so it's not 100 percent
// secure. If it turns out that we need more complete checks, we could add a
// special marker as internal field, which will definitely never occur anywhere
// else.
bool IsWasmObject(Object* object);
// Update memory references of code objects associated with the module
bool UpdateWasmModuleMemory(Handle<JSObject> object, Address old_start,
Address new_start, uint32_t old_size,
uint32_t new_size);
namespace testing {
// Decode, verify, and run the function labeled "main" in the
// given encoded module. The module should have no imports.
int32_t CompileAndRunWasmModule(Isolate* isolate, const byte* module_start,
const byte* module_end, bool asm_js = false);
} // namespace testing
} // namespace wasm
} // namespace internal
} // namespace v8
#endif // V8_WASM_MODULE_H_