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loop support
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+ naked calls
+ loop traps

GothicKit#58
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@Try
Try committed Jul 24, 2023
1 parent 33f6f6d commit 6588d2a
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Showing 2 changed files with 47 additions and 12 deletions.
32 changes: 25 additions & 7 deletions include/phoenix/vm.hh
View file
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,8 @@
namespace phoenix {
struct _ignore_return_value {};

struct naked_call {};

template <typename T>
static constexpr bool is_instance_ptr_v = false;

Expand Down Expand Up @@ -83,6 +85,7 @@ namespace phoenix {
static constexpr std::uint8_t none = 0;
static constexpr std::uint8_t vm_allow_null_instance_access = 1 << 1;
static constexpr std::uint8_t vm_ignore_const_specifier = 1 << 2;
static constexpr std::uint8_t vm_allow_loop_traps = 1 << 3;
} // namespace execution_flag

class vm : public script {
Expand Down Expand Up @@ -512,7 +515,7 @@ namespace phoenix {
if (sym->is_external())
throw vm_exception {"symbol is already an external"};

if constexpr (!std::is_same_v<void, R>) {
if constexpr (!std::is_same_v<void, R> && !std::is_same_v<naked_call, R>) {
if (!sym->has_return())
throw illegal_external_rtype(sym, "<non-void>");
if constexpr (is_instance_ptr_v<R>) {
Expand All @@ -530,43 +533,49 @@ namespace phoenix {
} else {
throw vm_exception {"unsupported return type"};
}
} else {
} else if (!std::is_same_v<naked_call, R>){
if (sym->has_return())
throw illegal_external_rtype(sym, "void");
}

std::vector<symbol*> params = find_parameters_for_function(sym);
if (params.size() < sizeof...(P))
if (params.size() < sizeof...(P) && !std::is_same_v<naked_call, R>)
throw illegal_external_definition {sym,
"too many arguments declared for function override " + sym->name() +
": declared " + std::to_string(sizeof...(P)) + " expected " +
std::to_string(params.size())};

if (params.size() > sizeof...(P))
if (params.size() > sizeof...(P) && !std::is_same_v<naked_call, R>)
throw illegal_external_definition {sym,
"not enough arguments declared for function override " +
sym->name() + ": declared " + std::to_string(sizeof...(P)) +
" expected " + std::to_string(params.size())};

if constexpr (sizeof...(P) > 0) {
if constexpr (sizeof...(P) > 0 && !std::is_same_v<naked_call, R>) {
check_external_params<0, P...>(params);
}

// *evil template hacking ensues*
_m_function_overrides[sym->address()] = [callback](vm& machine) {
_m_function_overrides[sym->address()] = [callback, sym](vm& machine) {
if constexpr (std::is_same_v<void, R>) {
machine.push_call(sym);
if constexpr (sizeof...(P) > 0) {
auto v = machine.pop_values_for_external<P...>();
std::apply(callback, v);
} else {
callback();
}
machine.pop_call();
} else if constexpr (std::is_same_v<phoenix::naked_call, R>){
callback(machine);
} else {
machine.push_call(sym);
if constexpr (sizeof...(P) > 0) {
machine.push_value_from_external(std::apply(callback, machine.pop_values_for_external<P...>()));
} else {
machine.push_value_from_external(callback());
}
machine.pop_call();
}
};

Expand Down Expand Up @@ -600,6 +609,8 @@ namespace phoenix {

PHOENIX_API void register_default_external_custom(const std::function<void(vm&, symbol&)>& callback);

PHOENIX_API void register_loop_trap(const std::function<void (symbol &)> &callback);

/// \brief Registers a function to be called when script execution fails.
///
/// A variety of exceptions can occur within the VM while executing. The function passed to this handler can
Expand All @@ -620,6 +631,8 @@ namespace phoenix {
/// \param sym The symbol to unsafe_call.
PHOENIX_API void unsafe_call(const symbol* sym);

PHOENIX_API void unsafe_jump(uint32_t address);

/// \return the symbol referring to the global <tt>var C_NPC self</tt>.
PHOENIX_API inline symbol* global_self() {
return _m_self_sym;
Expand Down Expand Up @@ -691,7 +704,7 @@ namespace phoenix {
/// \note Requires that sizeof...(Px) + 1 == defined.size().
template <int32_t i, typename P, typename... Px>
void check_external_params(const std::vector<symbol*>& defined) {
if constexpr (is_instance_ptr_v<P> || std::is_same_v<symbol*, P> || is_raw_instance_ptr_v<P>) {
if constexpr (is_instance_ptr_v<P> || is_raw_instance_ptr_v<P>) {
if (defined[i]->type() != datatype::instance)
throw illegal_external_param(defined[i], "instance", i + 1);
} else if constexpr (std::is_same_v<float, P>) {
Expand Down Expand Up @@ -918,6 +931,7 @@ namespace phoenix {
std::unordered_map<symbol*, std::function<void(vm&)>> _m_externals;
std::unordered_map<uint32_t, std::function<void(vm&)>> _m_function_overrides;
std::optional<std::function<void(vm&, symbol&)>> _m_default_external {std::nullopt};
std::function<void(symbol&)> _m_default_loop_trap;
std::optional<std::function<vm_exception_strategy(vm&, const script_error&, const instruction&)>>
_m_exception_handler {std::nullopt};

Expand All @@ -929,6 +943,10 @@ namespace phoenix {

symbol* _m_temporary_strings;

symbol* _m_loop_end_sym {};
symbol* _m_loop_break_sym {};
symbol* _m_loop_continue_sym {};

std::shared_ptr<instance> _m_instance;
std::uint32_t _m_pc {0};
std::uint8_t _m_flags {execution_flag::none};
Expand Down
27 changes: 22 additions & 5 deletions source/vm.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,12 @@ namespace phoenix {
_m_hero_sym = find_symbol_by_name("HERO");
_m_item_sym = find_symbol_by_name("ITEM");
_m_temporary_strings = add_temporary_strings_symbol();

if (_m_flags & execution_flag::vm_allow_loop_traps) {
_m_loop_end_sym = find_symbol_by_name("END");
_m_loop_break_sym = find_symbol_by_name("BREAK");
_m_loop_continue_sym = find_symbol_by_name("CONTINUE");
}
}

void vm::unsafe_call(const symbol* sym) {
Expand All @@ -93,6 +99,10 @@ namespace phoenix {
pop_call();
}

void vm::unsafe_jump(uint32_t address) {
this->jump(address);
}

bool vm::exec() {
auto instr = instruction_at(_m_pc);

Expand Down Expand Up @@ -206,11 +216,8 @@ namespace phoenix {
if (cb != _m_function_overrides.end()) {
// Guard against exceptions during external invocation.
stack_guard guard {this, sym->rtype()};

push_call(sym);
// Call maybe naked.
cb->second(*this);
pop_call();

// The stack is left intact.
guard.inhibit();
} else {
Expand Down Expand Up @@ -260,7 +267,11 @@ namespace phoenix {
if (sym == nullptr) {
throw vm_exception {"pushv: no symbol found for index"};
}
push_reference(sym, 0);
if ((_m_loop_end_sym == sym || _m_loop_break_sym==sym || _m_loop_continue_sym==sym) && _m_default_loop_trap) {
_m_default_loop_trap(*sym);
} else {
push_reference(sym, 0);
}
break;
case opcode::movi:
case opcode::movvf: {
Expand Down Expand Up @@ -660,6 +671,12 @@ namespace phoenix {
_m_default_external = callback;
}

void vm::register_loop_trap(const std::function<void (symbol &)> &callback) {
if (_m_flags & execution_flag::vm_allow_loop_traps)
throw vm_exception {"Loop traps are not enabled"};
_m_default_loop_trap = callback;
}

void vm::register_exception_handler(
const std::function<vm_exception_strategy(vm&, const script_error&, const instruction&)>& callback) {
_m_exception_handler = callback;
Expand Down

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