Files
scryer-prolog/src/prolog/machine/mod.rs

726 lines
25 KiB
Rust

use prolog_parser::ast::*;
use prolog_parser::tabled_rc::*;
use prolog::codegen::*;
use prolog::compile::*;
use prolog::debray_allocator::*;
use prolog::heap_print::*;
use prolog::instructions::*;
mod attributed_variables;
mod dynamic_database;
mod machine_errors;
pub(super) mod machine_state;
pub(super) mod term_expansion;
#[macro_use] mod machine_state_impl;
mod system_calls;
use prolog::machine::attributed_variables::*;
use prolog::machine::machine_state::*;
use std::collections::{HashMap, VecDeque};
use std::mem;
use std::ops::Index;
use std::rc::Rc;
#[derive(Copy, Clone)]
pub struct DynamicPredicateInfo {
pub(super) clauses_subsection_p: usize, // a LocalCodePtr::DirEntry value.
}
impl Default for DynamicPredicateInfo {
fn default() -> Self {
DynamicPredicateInfo { clauses_subsection_p: 0 }
}
}
pub type InSituCodeDir = HashMap<PredicateKey, usize>;
pub type DynamicCodeDir = HashMap<PredicateKey, DynamicPredicateInfo>;
pub struct IndexStore {
pub(super) atom_tbl: TabledData<Atom>,
pub(super) code_dir: CodeDir,
pub(super) dynamic_code_dir: DynamicCodeDir,
pub(super) in_situ_code_dir: InSituCodeDir,
pub(super) op_dir: OpDir,
pub(super) modules: ModuleDir,
}
enum RefOrOwned<'a, T: 'a> {
Borrowed(&'a T),
Owned(T)
}
impl<'a, T> RefOrOwned<'a, T> {
fn as_ref(&'a self) -> &'a T {
match self {
&RefOrOwned::Borrowed(r) => r,
&RefOrOwned::Owned(ref r) => r
}
}
}
impl IndexStore {
pub fn predicate_exists(&self, name: ClauseName, arity: usize,
op_spec: Option<(usize, Specifier)>)
-> bool
{
match ClauseType::from(name, arity, op_spec) {
ClauseType::Named(name, arity, _) =>
self.code_dir.contains_key(&(name, arity)),
ClauseType::Op(op_decl, ..) =>
self.code_dir.contains_key(&(op_decl.name(), op_decl.arity())),
_ => true
}
}
#[inline]
pub fn get_clause_subsection(&self, name: ClauseName, arity: usize) -> Option<DynamicPredicateInfo> {
self.dynamic_code_dir.get(&(name, arity)).cloned()
}
#[inline]
pub fn take_module(&mut self, name: ClauseName) -> Option<Module> {
self.modules.remove(&name)
}
#[inline]
pub fn insert_module(&mut self, module: Module) {
self.modules.insert(module.module_decl.name.clone(), module);
}
#[inline]
pub(super) fn new() -> Self {
IndexStore {
atom_tbl: TabledData::new(Rc::new("user".to_string())),
code_dir: CodeDir::new(),
dynamic_code_dir: DynamicCodeDir::new(),
in_situ_code_dir: InSituCodeDir::new(),
op_dir: default_op_dir(),
modules: ModuleDir::new(),
}
}
#[inline]
pub(super) fn copy_and_swap(&mut self, other: &mut IndexStore) {
self.code_dir = other.code_dir.clone();
self.op_dir = other.op_dir.clone();
mem::swap(&mut self.code_dir, &mut other.code_dir);
mem::swap(&mut self.op_dir, &mut other.op_dir);
mem::swap(&mut self.modules, &mut other.modules);
}
#[inline]
fn get_internal(&self, name: ClauseName, arity: usize, in_mod: ClauseName)
-> Option<ModuleCodeIndex>
{
self.modules.get(&in_mod)
.and_then(|ref module| module.code_dir.get(&(name, arity)))
.cloned()
}
pub(super) fn get_cleaner_sites(&self) -> (usize, usize) {
let r_w_h = clause_name!("run_cleaners_with_handling");
let r_wo_h = clause_name!("run_cleaners_without_handling");
let builtins = clause_name!("builtins");
let r_w_h = self.get_internal(r_w_h, 0, builtins.clone()).and_then(|item| item.local());
let r_wo_h = self.get_internal(r_wo_h, 1, builtins).and_then(|item| item.local());
if let Some(r_w_h) = r_w_h {
if let Some(r_wo_h) = r_wo_h {
return (r_w_h, r_wo_h);
}
}
return (0, 0);
}
}
pub type CompiledResult = (Predicate, VecDeque<TopLevel>);
impl CodeRepo {
#[inline]
fn new() -> Self {
CodeRepo {
cached_query: vec![],
goal_expanders: Code::new(),
term_expanders: Code::new(),
code: Code::new(),
in_situ_code: Code::new(),
term_dir: TermDir::new()
}
}
#[inline]
pub fn term_dir_entry_len(&self, key: PredicateKey) -> (usize, usize) {
self.term_dir.get(&key)
.map(|entry| ((entry.0).0.len(), entry.1.len()))
.unwrap_or((0,0))
}
#[inline]
pub fn truncate_terms(&mut self, key: PredicateKey, len: usize, queue_len: usize)
-> (Predicate, VecDeque<TopLevel>)
{
self.term_dir.get_mut(&key)
.map(|entry| (Predicate((entry.0).0.drain(len ..).collect()),
entry.1.drain(queue_len ..).collect()))
.unwrap_or((Predicate::new(), VecDeque::from(vec![])))
}
pub fn add_in_situ_result(&mut self, result: &CompiledResult, in_situ_code_dir: &mut InSituCodeDir,
flags: MachineFlags)
-> Result<(), SessionError>
{
let (ref decl, ref queue) = result;
let (name, arity) = decl.0.first().and_then(|cl| {
let arity = cl.arity();
cl.name().map(|name| (name, arity))
}).ok_or(SessionError::NamelessEntry)?;
let p = self.in_situ_code.len();
in_situ_code_dir.insert((name, arity), p);
let mut cg = CodeGenerator::<DebrayAllocator>::new(true, flags);
// clone the decl to avoid the need to wipe its register cells later.
let mut decl_code = cg.compile_predicate(&decl.0.clone())?;
compile_appendix(&mut decl_code, queue, true, flags)?;
self.in_situ_code.extend(decl_code.into_iter());
Ok(())
}
#[inline]
fn size_of_cached_query(&self) -> usize {
self.cached_query.len()
}
fn lookup_instr<'a>(&'a self, last_call: bool, p: &CodePtr) -> Option<RefOrOwned<'a, Line>>
{
match p {
&CodePtr::Local(LocalCodePtr::UserGoalExpansion(p)) =>
if p < self.goal_expanders.len() {
Some(RefOrOwned::Borrowed(&self.goal_expanders[p]))
} else {
None
},
&CodePtr::Local(LocalCodePtr::UserTermExpansion(p)) =>
if p < self.term_expanders.len() {
Some(RefOrOwned::Borrowed(&self.term_expanders[p]))
} else {
None
},
&CodePtr::Local(LocalCodePtr::TopLevel(_, p)) =>
if p < self.cached_query.len() {
Some(RefOrOwned::Borrowed(&self.cached_query[p]))
} else {
None
},
&CodePtr::Local(LocalCodePtr::InSituDirEntry(p)) =>
Some(RefOrOwned::Borrowed(&self.in_situ_code[p])),
&CodePtr::Local(LocalCodePtr::DirEntry(p)) =>
Some(RefOrOwned::Borrowed(&self.code[p])),
&CodePtr::BuiltInClause(ref built_in, _) => {
let call_clause = call_clause!(ClauseType::BuiltIn(built_in.clone()),
built_in.arity(),
0, last_call);
Some(RefOrOwned::Owned(call_clause))
},
&CodePtr::CallN(arity, _) => {
let call_clause = call_clause!(ClauseType::CallN, arity, 0, last_call);
Some(RefOrOwned::Owned(call_clause))
},
&CodePtr::VerifyAttrInterrupt(p) =>
Some(RefOrOwned::Borrowed(&self.code[p])),
&CodePtr::DynamicTransaction(..) =>
None
}
}
}
pub struct MachinePolicies {
call_policy: Box<CallPolicy>,
cut_policy: Box<CutPolicy>,
}
impl MachinePolicies {
#[inline]
fn new() -> Self {
MachinePolicies {
call_policy: Box::new(DefaultCallPolicy {}),
cut_policy: Box::new(DefaultCutPolicy {}),
}
}
}
pub struct Machine {
pub(super) machine_st: MachineState,
pub(super) policies: MachinePolicies,
pub(super) indices: IndexStore,
pub(super) code_repo: CodeRepo
}
impl Index<LocalCodePtr> for CodeRepo {
type Output = Line;
fn index(&self, ptr: LocalCodePtr) -> &Self::Output {
match ptr {
LocalCodePtr::InSituDirEntry(p) => &self.in_situ_code[p],
LocalCodePtr::TopLevel(_, p) => &self.cached_query[p],
LocalCodePtr::DirEntry(p) => &self.code[p],
LocalCodePtr::UserGoalExpansion(p) => &self.goal_expanders[p],
LocalCodePtr::UserTermExpansion(p) => &self.term_expanders[p],
}
}
}
impl Index<LocalCodePtr> for Machine {
type Output = Line;
fn index(&self, ptr: LocalCodePtr) -> &Self::Output {
&self.code_repo[ptr]
}
}
impl SubModuleUser for IndexStore {
fn atom_tbl(&self) -> TabledData<Atom> {
self.atom_tbl.clone()
}
fn op_dir(&mut self) -> &mut OpDir {
&mut self.op_dir
}
fn get_code_index(&self, key: PredicateKey, module: ClauseName) -> Option<CodeIndex>
{
match module.as_str() {
"user" | "builtin" => self.code_dir.get(&key).cloned(),
_ => self.modules.get(&module).and_then(|ref module| {
module.code_dir.get(&key).cloned().map(CodeIndex::from)
})
}
}
fn remove_code_index(&mut self, key: PredicateKey) {
self.code_dir.remove(&key);
}
fn insert_dir_entry(&mut self, name: ClauseName, arity: usize, idx: ModuleCodeIndex)
{
if let Some(ref mut code_idx) = self.code_dir.get_mut(&(name.clone(), arity)) {
if !code_idx.is_undefined() {
println!("warning: overwriting {}/{}", &name, arity);
}
set_code_index!(code_idx, idx.0, idx.1);
return;
}
self.code_dir.insert((name, arity), CodeIndex::from(idx));
}
fn use_qualified_module(&mut self, code_repo: &mut CodeRepo, flags: MachineFlags,
submodule: &Module, exports: &Vec<PredicateKey>)
-> Result<(), SessionError>
{
use_qualified_module(self, submodule, exports)?;
submodule.dump_expansions(code_repo, flags).map_err(SessionError::from)
}
fn use_module(&mut self, code_repo: &mut CodeRepo, flags: MachineFlags, submodule: &Module)
-> Result<(), SessionError>
{
use_module(self, submodule)?;
if !submodule.inserted_expansions {
submodule.dump_expansions(code_repo, flags).map_err(SessionError::from)
} else {
Ok(())
}
}
}
static BUILTINS: &str = include_str!("../lib/builtins.pl");
static LISTS: &str = include_str!("../lib/lists.pl");
static QUEUES: &str = include_str!("../lib/queues.pl");
static ERROR: &str = include_str!("../lib/error.pl");
static BETWEEN: &str = include_str!("../lib/between.pl");
static TERMS: &str = include_str!("../lib/terms.pl");
static DCGS: &str = include_str!("../lib/dcgs.pl");
static ATTS: &str = include_str!("../lib/atts.pl");
static DIF: &str = include_str!("../lib/dif.pl");
static FREEZE: &str = include_str!("../lib/freeze.pl");
static REIF: &str = include_str!("../lib/reif.pl");
impl Machine {
fn compile_special_forms(&mut self) {
match compile_special_form(self, VERIFY_ATTRS.as_bytes()) {
Ok(code) => {
self.machine_st.attr_var_init.verify_attrs_loc = self.code_repo.code.len();
self.code_repo.code.extend(code.into_iter());
},
Err(_) => panic!("Machine::compile_special_forms() failed at VERIFY_ATTRS")
}
match compile_special_form(self, PROJECT_ATTRS.as_bytes()) {
Ok(code) => {
self.machine_st.attr_var_init.project_attrs_loc = self.code_repo.code.len();
self.code_repo.code.extend(code.into_iter());
},
Err(_) => panic!("Machine::compile_special_forms() failed at PROJECT_ATTRS")
}
}
fn compile_libraries(&mut self) {
compile_user_module(self, LISTS.as_bytes());
compile_user_module(self, QUEUES.as_bytes());
compile_user_module(self, ERROR.as_bytes());
compile_user_module(self, BETWEEN.as_bytes());
compile_user_module(self, TERMS.as_bytes());
compile_user_module(self, DCGS.as_bytes());
compile_user_module(self, ATTS.as_bytes());
compile_user_module(self, DIF.as_bytes());
compile_user_module(self, FREEZE.as_bytes());
compile_user_module(self, REIF.as_bytes());
}
pub fn new() -> Self {
let mut wam = Machine {
machine_st: MachineState::new(),
policies: MachinePolicies::new(),
indices: IndexStore::new(),
code_repo: CodeRepo::new()
};
let atom_tbl = wam.indices.atom_tbl.clone();
compile_listing(&mut wam, BUILTINS.as_bytes(),
default_index_store!(atom_tbl.clone()));
wam.compile_libraries();
wam.compile_special_forms();
wam
}
#[inline]
pub fn machine_flags(&self) -> MachineFlags {
self.machine_st.flags
}
pub fn add_batched_code(&mut self, code: Code, code_dir: CodeDir) -> Result<(), SessionError>
{
for (ref key, ref idx) in code_dir.iter() {
match ClauseType::from(key.0.clone(), key.1, None) {
ClauseType::Named(..) | ClauseType::Op(..) => {},
_ => {
// ensure we don't try to overwrite the name/arity of a builtin.
let err_str = format!("{}/{}", key.0, key.1);
let err_str = clause_name!(err_str, self.indices.atom_tbl());
return Err(SessionError::CannotOverwriteBuiltIn(err_str));
}
};
if let Some(ref existing_idx) = self.indices.code_dir.get(&key) {
// ensure we don't try to overwrite an existing predicate from a different module.
if !existing_idx.is_undefined() && !idx.is_undefined() {
// allow the overwriting of user-level predicates by all other predicates.
if existing_idx.module_name() == key.0.owning_module() {
continue;
}
if existing_idx.module_name() != idx.module_name() {
let err_str = format!("{}/{} from module {}", key.0, key.1,
existing_idx.module_name().as_str());
let err_str = clause_name!(err_str, self.indices.atom_tbl());
return Err(SessionError::CannotOverwriteImport(err_str));
}
}
}
}
// error detection has finished, so update the master index of keys.
for (key, idx) in code_dir {
if let Some(ref mut master_idx) = self.indices.code_dir.get_mut(&key) {
// ensure we don't double borrow if master_idx == idx.
// we don't need to modify anything in that case.
if !Rc::ptr_eq(&master_idx.0, &idx.0) {
set_code_index!(master_idx, idx.0.borrow().0, idx.module_name());
}
continue;
}
self.indices.code_dir.insert(key.clone(), idx.clone());
}
self.code_repo.code.extend(code.into_iter());
Ok(())
}
#[inline]
pub fn add_batched_ops(&mut self, op_dir: OpDir) {
self.indices.op_dir.extend(op_dir.into_iter());
}
#[inline]
pub fn add_module(&mut self, module: Module, code: Code) {
self.indices.modules.insert(module.module_decl.name.clone(), module);
self.code_repo.code.extend(code.into_iter());
}
pub fn code_size(&self) -> usize {
self.code_repo.code.len()
}
fn fail(&mut self) -> EvalSession
{
if self.machine_st.ball.stub.len() > 0 {
let h = self.machine_st.heap.h;
self.machine_st.copy_and_align_ball_to_heap(0);
let err_str = self.machine_st.print_exception(Addr::HeapCell(h),
&HeapVarDict::new(),
PrinterOutputter::new())
.result();
let err_str = clause_name!(err_str, self.indices.atom_tbl());
EvalSession::from(SessionError::QueryFailureWithException(err_str))
} else {
EvalSession::from(SessionError::QueryFailure)
}
}
pub fn submit_query(&mut self, code: Code, alloc_locs: AllocVarDict) -> EvalSession
{
let mut heap_locs = HashMap::new();
self.code_repo.cached_query = code;
self.run_query(&alloc_locs, &mut heap_locs);
if self.machine_st.fail {
self.fail()
} else {
EvalSession::InitialQuerySuccess(alloc_locs, heap_locs)
}
}
fn record_var_places(&self, chunk_num: usize, alloc_locs: &AllocVarDict,
heap_locs: &mut HeapVarDict)
{
for (var, var_data) in alloc_locs {
match var_data {
&VarData::Perm(p) if p > 0 =>
if !heap_locs.contains_key(var) {
let e = self.machine_st.e;
let r = var_data.as_reg_type().reg_num();
let addr = self.machine_st.and_stack[e][r].clone();
heap_locs.insert(var.clone(), addr);
},
&VarData::Temp(cn, _, _) if cn == chunk_num => {
let r = var_data.as_reg_type();
if r.reg_num() != 0 {
let addr = self.machine_st[r].clone();
heap_locs.insert(var.clone(), addr);
}
},
_ => {}
}
}
}
pub(super)
fn run_query(&mut self, alloc_locs: &AllocVarDict, heap_locs: &mut HeapVarDict)
{
let end_ptr = top_level_code_ptr!(0, self.code_repo.size_of_cached_query());
while self.machine_st.p < end_ptr {
if let CodePtr::Local(LocalCodePtr::TopLevel(mut cn, p)) = self.machine_st.p {
match &self.code_repo[LocalCodePtr::TopLevel(cn, p)] {
&Line::Control(ref ctrl_instr) if ctrl_instr.is_jump_instr() => {
self.record_var_places(cn, alloc_locs, heap_locs);
cn += 1;
},
_ => {}
}
self.machine_st.p = top_level_code_ptr!(cn, p);
}
self.machine_st.query_stepper(&mut self.indices, &mut self.policies, &mut self.code_repo);
match self.machine_st.p {
CodePtr::Local(LocalCodePtr::TopLevel(_, p)) if p > 0 => {},
CodePtr::DynamicTransaction(trans_type, p) => {
// self.code_repo.cached_query is about to be overwritten by the term expander,
// so hold onto it locally and restore it after the compiler has finished.
let cached_query = mem::replace(&mut self.code_repo.cached_query, vec![]);
self.dynamic_transaction(trans_type, p);
if let CodePtr::Local(LocalCodePtr::TopLevel(_, 0)) = self.machine_st.p {
if heap_locs.is_empty() {
self.record_var_places(0, alloc_locs, heap_locs);
}
self.code_repo.cached_query = cached_query;
break;
}
self.code_repo.cached_query = cached_query;
},
_ => {
if heap_locs.is_empty() {
self.record_var_places(0, alloc_locs, heap_locs);
}
break;
}
};
}
}
pub fn continue_query(&mut self, alloc_l: &AllocVarDict, heap_l: &mut HeapVarDict) -> EvalSession
{
if !self.or_stack_is_empty() {
let b = self.machine_st.b - 1;
self.machine_st.p = self.machine_st.or_stack[b].bp.clone();
if let CodePtr::Local(LocalCodePtr::TopLevel(_, 0)) = self.machine_st.p {
return EvalSession::from(SessionError::QueryFailure);
}
self.run_query(alloc_l, heap_l);
if self.machine_st.fail {
self.fail()
} else {
EvalSession::SubsequentQuerySuccess
}
} else {
EvalSession::from(SessionError::QueryFailure)
}
}
pub fn heap_view<Outputter>(&self, var_dir: &HeapVarDict, mut output: Outputter) -> Outputter
where Outputter: HCValueOutputter
{
let mut sorted_vars: Vec<(&Rc<Var>, &Addr)> = var_dir.iter().collect();
sorted_vars.sort_by_key(|ref v| v.0);
for (var, addr) in sorted_vars {
output = self.machine_st.print_var_eq(var.clone(), addr.clone(), var_dir, output);
}
output
}
pub fn or_stack_is_empty(&self) -> bool {
self.machine_st.b == 0
}
pub fn clear(&mut self) {
let mut machine = Machine::new();
mem::swap(self, &mut machine);
}
pub fn reset(&mut self) {
self.policies.cut_policy = Box::new(DefaultCutPolicy {});
self.machine_st.reset();
}
}
impl MachineState {
fn execute_instr(&mut self, indices: &mut IndexStore, policies: &mut MachinePolicies,
code_repo: &CodeRepo)
{
let instr = match code_repo.lookup_instr(self.last_call, &self.p) {
Some(instr) => instr,
None => return
};
match instr.as_ref() {
&Line::Arithmetic(ref arith_instr) =>
self.execute_arith_instr(arith_instr),
&Line::Choice(ref choice_instr) =>
self.execute_choice_instr(choice_instr, &mut policies.call_policy),
&Line::Cut(ref cut_instr) =>
self.execute_cut_instr(cut_instr, &mut policies.cut_policy),
&Line::Control(ref control_instr) =>
self.execute_ctrl_instr(indices, &mut policies.call_policy,
&mut policies.cut_policy, control_instr),
&Line::Fact(ref fact_instr) => {
self.execute_fact_instr(&fact_instr);
self.p += 1;
},
&Line::Indexing(ref indexing_instr) =>
self.execute_indexing_instr(&indexing_instr),
&Line::IndexedChoice(ref choice_instr) =>
self.execute_indexed_choice_instr(choice_instr, &mut policies.call_policy),
&Line::Query(ref query_instr) => {
self.execute_query_instr(&query_instr);
self.p += 1;
}
}
}
fn backtrack(&mut self)
{
if self.b > 0 {
let b = self.b - 1;
self.b0 = self.or_stack[b].b0;
self.p = self.or_stack[b].bp.clone();
if let CodePtr::Local(LocalCodePtr::TopLevel(_, p)) = self.p {
self.fail = p == 0;
} else {
self.fail = false;
}
} else {
self.p = CodePtr::Local(LocalCodePtr::TopLevel(0, 0));
}
}
fn query_stepper(&mut self, indices: &mut IndexStore, policies: &mut MachinePolicies,
code_repo: &mut CodeRepo)
{
loop {
self.execute_instr(indices, policies, code_repo);
if self.fail {
self.backtrack();
}
match self.p {
CodePtr::Local(LocalCodePtr::DirEntry(p))
if p < code_repo.code.len() => {},
CodePtr::Local(LocalCodePtr::UserTermExpansion(p))
if p < code_repo.term_expanders.len() => {},
CodePtr::Local(LocalCodePtr::UserTermExpansion(_)) =>
self.fail = true,
CodePtr::Local(LocalCodePtr::UserGoalExpansion(p))
if p < code_repo.goal_expanders.len() => {},
CodePtr::Local(LocalCodePtr::UserGoalExpansion(_)) =>
self.fail = true,
CodePtr::Local(LocalCodePtr::InSituDirEntry(p))
if p < code_repo.in_situ_code.len() => {},
CodePtr::Local(_) | CodePtr::DynamicTransaction(..) =>
break,
CodePtr::VerifyAttrInterrupt(p) =>
self.verify_attr_interrupt(p),
_ => {}
}
}
}
}