wasmer/lib/llvm-backend/cpp/object_loader.hh

304 lines
8.6 KiB
C++

#pragma once
#include <cstddef>
#include <cstdint>
#include <exception>
#include <iostream>
#include <sstream>
#include <setjmp.h>
#include <functional>
#include <llvm/ExecutionEngine/RuntimeDyld.h>
typedef enum {
PROTECT_NONE,
PROTECT_READ,
PROTECT_READ_WRITE,
PROTECT_READ_EXECUTE,
} mem_protect_t;
typedef enum {
RESULT_OK,
RESULT_ALLOCATE_FAILURE,
RESULT_PROTECT_FAILURE,
RESULT_DEALLOC_FAILURE,
RESULT_OBJECT_LOAD_FAILURE,
} result_t;
typedef result_t (*alloc_memory_t)(size_t size, mem_protect_t protect,
uint8_t **ptr_out, size_t *size_out);
typedef result_t (*protect_memory_t)(uint8_t *ptr, size_t size,
mem_protect_t protect);
typedef result_t (*dealloc_memory_t)(uint8_t *ptr, size_t size);
typedef uintptr_t (*lookup_vm_symbol_t)(const char *name_ptr, size_t length);
typedef void (*fde_visitor_t)(uint8_t *fde);
typedef result_t (*visit_fde_t)(uint8_t *fde, size_t size,
fde_visitor_t visitor);
typedef void (*trampoline_t)(void *, void *, void *, void *);
typedef struct {
/* Memory management. */
alloc_memory_t alloc_memory;
protect_memory_t protect_memory;
dealloc_memory_t dealloc_memory;
lookup_vm_symbol_t lookup_vm_symbol;
visit_fde_t visit_fde;
} callbacks_t;
typedef struct {
size_t data, vtable;
} box_any_t;
struct MemoryManager : llvm::RuntimeDyld::MemoryManager {
public:
MemoryManager(callbacks_t callbacks) : callbacks(callbacks) {}
virtual ~MemoryManager() override;
inline uint8_t *get_stack_map_ptr() const { return stack_map_ptr; }
inline size_t get_stack_map_size() const { return stack_map_size; }
inline uint8_t *get_code_ptr() const { return (uint8_t *)code_start_ptr; }
inline size_t get_code_size() const { return code_size; }
virtual uint8_t *allocateCodeSection(uintptr_t size, unsigned alignment,
unsigned section_id,
llvm::StringRef section_name) override;
virtual uint8_t *allocateDataSection(uintptr_t size, unsigned alignment,
unsigned section_id,
llvm::StringRef section_name,
bool read_only) override;
virtual void reserveAllocationSpace(uintptr_t code_size, uint32_t code_align,
uintptr_t read_data_size,
uint32_t read_data_align,
uintptr_t read_write_data_size,
uint32_t read_write_data_align) override;
/* Turn on the `reserveAllocationSpace` callback. */
virtual bool needsToReserveAllocationSpace() override;
virtual void registerEHFrames(uint8_t *addr, uint64_t LoadAddr,
size_t size) override;
virtual void deregisterEHFrames() override;
virtual bool finalizeMemory(std::string *ErrMsg = nullptr) override;
virtual void notifyObjectLoaded(llvm::RuntimeDyld &RTDyld,
const llvm::object::ObjectFile &Obj) override;
private:
struct Section {
uint8_t *base;
size_t size;
};
uint8_t *allocate_bump(Section &section, uintptr_t &bump_ptr, size_t size,
size_t align);
Section code_section, read_section, readwrite_section;
uintptr_t code_start_ptr;
size_t code_size;
uintptr_t code_bump_ptr, read_bump_ptr, readwrite_bump_ptr;
uint8_t *eh_frame_ptr;
size_t eh_frame_size;
bool eh_frames_registered = false;
callbacks_t callbacks;
uint8_t *stack_map_ptr = nullptr;
size_t stack_map_size = 0;
};
struct WasmException: std::exception {
public:
virtual std::string description() const noexcept = 0;
};
void catch_unwind(std::function<void()>&& f);
[[noreturn]] void unsafe_unwind(std::exception *exception);
struct UncatchableException : WasmException {
public:
virtual std::string description() const noexcept override {
return "Uncatchable exception";
}
};
struct UserException : UncatchableException {
public:
UserException(size_t data, size_t vtable) : error_data({data, vtable}) {}
virtual std::string description() const noexcept override {
return "user exception";
}
// The parts of a `Box<dyn Any>`.
box_any_t error_data;
};
struct BreakpointException : UncatchableException {
public:
BreakpointException(uintptr_t callback) : callback(callback) {}
virtual std::string description() const noexcept override {
return "breakpoint exception";
}
uintptr_t callback;
};
struct WasmModule {
public:
WasmModule(const uint8_t *object_start, size_t object_size,
callbacks_t callbacks);
void *get_func(llvm::StringRef name) const;
uint8_t *get_stack_map_ptr() const;
size_t get_stack_map_size() const;
uint8_t *get_code_ptr() const;
size_t get_code_size() const;
bool _init_failed = false;
private:
std::unique_ptr<MemoryManager> memory_manager;
std::unique_ptr<llvm::object::ObjectFile> object_file;
std::unique_ptr<llvm::RuntimeDyld> runtime_dyld;
};
struct WasmTrap : UncatchableException {
public:
enum Type {
Unreachable = 0,
IncorrectCallIndirectSignature = 1,
MemoryOutOfBounds = 2,
CallIndirectOOB = 3,
IllegalArithmetic = 4,
Unknown,
};
WasmTrap(Type type) : type(type) {}
virtual std::string description() const noexcept override {
std::ostringstream ss;
ss << "WebAssembly trap:" << '\n' << " - type: " << type << '\n';
return ss.str();
}
Type type;
private:
friend std::ostream &operator<<(std::ostream &out, const Type &ty) {
switch (ty) {
case Type::Unreachable:
out << "unreachable";
break;
case Type::IncorrectCallIndirectSignature:
out << "incorrect call_indirect signature";
break;
case Type::MemoryOutOfBounds:
out << "memory access out-of-bounds";
break;
case Type::CallIndirectOOB:
out << "call_indirect out-of-bounds";
break;
case Type::IllegalArithmetic:
out << "illegal arithmetic operation";
break;
case Type::Unknown:
default:
out << "unknown";
break;
}
return out;
}
};
struct CatchableException : WasmException {
public:
CatchableException(uint32_t type_id, uint32_t value_num)
: type_id(type_id), value_num(value_num) {}
virtual std::string description() const noexcept override {
return "catchable exception";
}
uint32_t type_id, value_num;
uint64_t values[1];
};
extern "C" {
void callback_trampoline(void *, void *);
result_t module_load(const uint8_t *mem_ptr, size_t mem_size,
callbacks_t callbacks, WasmModule **module_out) {
*module_out = new WasmModule(mem_ptr, mem_size, callbacks);
if ((*module_out)->_init_failed) {
return RESULT_OBJECT_LOAD_FAILURE;
}
return RESULT_OK;
}
[[noreturn]] void throw_trap(WasmTrap::Type ty) { unsafe_unwind(new WasmTrap(ty)); }
void module_delete(WasmModule *module) { delete module; }
// Throw a fat pointer that's assumed to be `*mut dyn Any` on the rust
// side.
[[noreturn]] void throw_any(size_t data, size_t vtable) {
unsafe_unwind(new UserException(data, vtable));
}
// Throw a pointer that's assumed to be codegen::BreakpointHandler on the
// rust side.
[[noreturn]] void throw_breakpoint(uintptr_t callback) {
unsafe_unwind(new BreakpointException(callback));
}
bool invoke_trampoline(trampoline_t trampoline, void *ctx, void *func,
void *params, void *results, WasmTrap::Type *trap_out,
box_any_t *user_error, void *invoke_env) noexcept {
try {
catch_unwind([trampoline, ctx, func, params, results]() {
trampoline(ctx, func, params, results);
});
return true;
} catch (const WasmTrap &e) {
*trap_out = e.type;
return false;
} catch (const UserException &e) {
*user_error = e.error_data;
return false;
} catch (const BreakpointException &e) {
callback_trampoline(user_error, (void *)e.callback);
return false;
} catch (const WasmException &e) {
*trap_out = WasmTrap::Type::Unknown;
return false;
} catch (...) {
*trap_out = WasmTrap::Type::Unknown;
return false;
}
}
void *get_func_symbol(WasmModule *module, const char *name) {
return module->get_func(llvm::StringRef(name));
}
const uint8_t *llvm_backend_get_stack_map_ptr(const WasmModule *module) {
return module->get_stack_map_ptr();
}
size_t llvm_backend_get_stack_map_size(const WasmModule *module) {
return module->get_stack_map_size();
}
const uint8_t *llvm_backend_get_code_ptr(const WasmModule *module) {
return module->get_code_ptr();
}
size_t llvm_backend_get_code_size(const WasmModule *module) {
return module->get_code_size();
}
}