1166 lines
45 KiB
Rust
1166 lines
45 KiB
Rust
//! Module implementing the [`AST`] optimizer.
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use crate::ast::{Expr, OpAssignment, Stmt};
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use crate::dynamic::AccessMode;
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use crate::engine::{KEYWORD_DEBUG, KEYWORD_EVAL, KEYWORD_FN_PTR, KEYWORD_PRINT, KEYWORD_TYPE_OF};
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use crate::fn_builtin::get_builtin_binary_op_fn;
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use crate::token::Token;
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use crate::utils::get_hasher;
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use crate::{
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calc_fn_hash, calc_fn_params_hash, combine_hashes, Dynamic, Engine, FnPtr, ImmutableString,
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Module, Position, Scope, StaticVec, AST,
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};
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#[cfg(feature = "no_std")]
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use std::prelude::v1::*;
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use std::{
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any::TypeId,
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hash::{Hash, Hasher},
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mem,
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};
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/// Level of optimization performed.
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#[derive(Debug, Eq, PartialEq, Hash, Clone, Copy)]
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pub enum OptimizationLevel {
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/// No optimization performed.
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None,
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/// Only perform simple optimizations without evaluating functions.
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Simple,
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/// Full optimizations performed, including evaluating functions.
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/// Take care that this may cause side effects as it essentially assumes that all functions are pure.
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Full,
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}
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impl Default for OptimizationLevel {
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#[inline(always)]
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fn default() -> Self {
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if cfg!(feature = "no_optimize") {
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Self::None
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} else {
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Self::Simple
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}
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}
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}
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/// Mutable state throughout an optimization pass.
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#[derive(Debug, Clone)]
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struct State<'a> {
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/// Has the [`AST`] been changed during this pass?
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changed: bool,
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/// Collection of constants to use for eager function evaluations.
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variables: Vec<(String, AccessMode, Option<Dynamic>)>,
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/// Activate constants propagation?
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propagate_constants: bool,
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/// An [`Engine`] instance for eager function evaluation.
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engine: &'a Engine,
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/// [Module] containing script-defined functions.
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lib: &'a [&'a Module],
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/// Optimization level.
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optimization_level: OptimizationLevel,
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}
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impl<'a> State<'a> {
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/// Create a new State.
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#[inline(always)]
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pub fn new(
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engine: &'a Engine,
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lib: &'a [&'a Module],
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optimization_level: OptimizationLevel,
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) -> Self {
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Self {
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changed: false,
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variables: vec![],
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propagate_constants: true,
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engine,
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lib,
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optimization_level,
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}
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}
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/// Set the [`AST`] state to be dirty (i.e. changed).
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#[inline(always)]
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pub fn set_dirty(&mut self) {
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self.changed = true;
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}
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/// Set the [`AST`] state to be not dirty (i.e. unchanged).
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#[inline(always)]
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pub fn clear_dirty(&mut self) {
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self.changed = false;
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}
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/// Is the [`AST`] dirty (i.e. changed)?
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#[inline(always)]
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pub fn is_dirty(&self) -> bool {
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self.changed
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}
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/// Prune the list of constants back to a specified size.
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#[inline(always)]
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pub fn restore_var(&mut self, len: usize) {
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self.variables.truncate(len)
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}
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/// Add a new constant to the list.
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#[inline(always)]
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pub fn push_var(&mut self, name: &str, access: AccessMode, value: Option<Dynamic>) {
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self.variables.push((name.into(), access, value))
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}
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/// Look up a constant from the list.
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#[inline]
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pub fn find_constant(&self, name: &str) -> Option<&Dynamic> {
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if !self.propagate_constants {
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return None;
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}
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self.variables.iter().rev().find_map(|(n, access, value)| {
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if n == name {
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match access {
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AccessMode::ReadWrite => None,
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AccessMode::ReadOnly => value.as_ref(),
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}
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} else {
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None
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}
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})
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}
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}
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// Has a system function a Rust-native override?
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fn has_native_fn(state: &State, hash_script: u64, arg_types: &[TypeId]) -> bool {
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let hash_params = calc_fn_params_hash(arg_types.iter().cloned());
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let hash = combine_hashes(hash_script, hash_params);
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// First check registered functions
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state.engine.global_namespace.contains_fn(hash)
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// Then check packages
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|| state.engine.global_modules.iter().any(|m| m.contains_fn(hash))
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// Then check sub-modules
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|| state.engine.global_sub_modules.values().any(|m| m.contains_qualified_fn(hash))
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}
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/// Call a registered function
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fn call_fn_with_constant_arguments(
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state: &State,
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fn_name: &str,
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arg_values: &mut [Dynamic],
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) -> Option<Dynamic> {
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state
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.engine
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.call_native_fn(
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&mut Default::default(),
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&mut Default::default(),
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state.lib,
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fn_name,
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calc_fn_hash(fn_name, arg_values.len()),
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&mut arg_values.iter_mut().collect::<StaticVec<_>>(),
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false,
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false,
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Position::NONE,
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)
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.ok()
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.map(|(v, _)| v)
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}
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/// Optimize a block of [statements][Stmt].
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fn optimize_stmt_block(
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mut statements: Vec<Stmt>,
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state: &mut State,
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preserve_result: bool,
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is_internal: bool,
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reduce_return: bool,
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) -> Vec<Stmt> {
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if statements.is_empty() {
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return statements;
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}
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let mut is_dirty = state.is_dirty();
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let is_pure = if is_internal {
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Stmt::is_internally_pure
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} else {
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Stmt::is_pure
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};
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loop {
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state.clear_dirty();
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let orig_constants_len = state.variables.len(); // Original number of constants in the state, for restore later
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let orig_propagate_constants = state.propagate_constants;
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// Remove everything following control flow breaking statements
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let mut dead_code = false;
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statements.retain(|stmt| {
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if dead_code {
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state.set_dirty();
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false
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} else if stmt.is_control_flow_break() {
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dead_code = true;
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true
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} else {
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true
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}
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});
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// Optimize each statement in the block
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statements.iter_mut().for_each(|stmt| {
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match stmt {
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// Add constant literals into the state
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Stmt::Const(value_expr, x, _, _) => {
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optimize_expr(value_expr, state, false);
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if value_expr.is_constant() {
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state.push_var(
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&x.name,
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AccessMode::ReadOnly,
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value_expr.get_constant_value(),
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);
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}
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}
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// Add variables into the state
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Stmt::Let(value_expr, x, _, _) => {
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optimize_expr(value_expr, state, false);
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state.push_var(&x.name, AccessMode::ReadWrite, None);
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}
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// Optimize the statement
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_ => optimize_stmt(stmt, state, preserve_result),
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}
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});
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// Remove all pure statements except the last one
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let mut index = 0;
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let mut first_non_constant = statements
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.iter()
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.rev()
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.enumerate()
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.find_map(|(i, stmt)| match stmt {
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stmt if !is_pure(stmt) => Some(i),
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Stmt::Let(e, _, _, _) | Stmt::Const(e, _, _, _) | Stmt::Expr(e)
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if !e.is_constant() =>
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{
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Some(i)
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}
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#[cfg(not(feature = "no_module"))]
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Stmt::Import(e, _, _) if !e.is_constant() => Some(i),
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_ => None,
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})
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.map_or(0, |n| statements.len() - n - 1);
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while index < statements.len() {
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if preserve_result && index >= statements.len() - 1 {
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break;
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} else {
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match &statements[index] {
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stmt if is_pure(stmt) && index >= first_non_constant => {
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state.set_dirty();
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statements.remove(index);
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}
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stmt if stmt.is_pure() => {
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state.set_dirty();
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if index < first_non_constant {
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first_non_constant -= 1;
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}
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statements.remove(index);
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}
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_ => index += 1,
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}
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}
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}
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// Remove all pure statements that do not return values at the end of a block.
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// We cannot remove anything for non-pure statements due to potential side-effects.
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if preserve_result {
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loop {
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match &mut statements[..] {
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// { return; } -> {}
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[Stmt::Return(crate::ast::ReturnType::Return, None, _)] if reduce_return => {
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state.set_dirty();
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statements.clear();
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}
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[stmt] if !stmt.returns_value() && is_pure(stmt) => {
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state.set_dirty();
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statements.clear();
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}
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// { ...; return; } -> { ... }
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[.., last_stmt, Stmt::Return(crate::ast::ReturnType::Return, None, _)]
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if reduce_return && !last_stmt.returns_value() =>
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{
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state.set_dirty();
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statements.pop().unwrap();
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}
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// { ...; return val; } -> { ...; val }
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[.., Stmt::Return(crate::ast::ReturnType::Return, expr, pos)]
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if reduce_return =>
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{
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state.set_dirty();
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*statements.last_mut().unwrap() = if let Some(expr) = expr {
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Stmt::Expr(mem::take(expr))
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} else {
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Stmt::Noop(*pos)
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};
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}
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[.., second_last_stmt, Stmt::Noop(_)] if second_last_stmt.returns_value() => {}
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[.., second_last_stmt, last_stmt]
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if !last_stmt.returns_value() && is_pure(last_stmt) =>
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{
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state.set_dirty();
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if second_last_stmt.returns_value() {
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*statements.last_mut().unwrap() = Stmt::Noop(last_stmt.position());
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} else {
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statements.pop().unwrap();
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}
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}
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_ => break,
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}
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}
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} else {
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loop {
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match &statements[..] {
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[stmt] if is_pure(stmt) => {
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state.set_dirty();
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statements.clear();
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}
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// { ...; return; } -> { ... }
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[.., Stmt::Return(crate::ast::ReturnType::Return, None, _)]
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if reduce_return =>
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{
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state.set_dirty();
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statements.pop().unwrap();
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}
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// { ...; return pure_val; } -> { ... }
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[.., Stmt::Return(crate::ast::ReturnType::Return, Some(expr), _)]
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if reduce_return && expr.is_pure() =>
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{
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state.set_dirty();
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statements.pop().unwrap();
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}
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[.., last_stmt] if is_pure(last_stmt) => {
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state.set_dirty();
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statements.pop().unwrap();
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}
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_ => break,
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}
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}
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}
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// Pop the stack and remove all the local constants
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state.restore_var(orig_constants_len);
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state.propagate_constants = orig_propagate_constants;
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if !state.is_dirty() {
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break;
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}
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is_dirty = true;
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}
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if is_dirty {
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state.set_dirty();
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}
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statements.shrink_to_fit();
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statements
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}
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/// Optimize a [statement][Stmt].
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fn optimize_stmt(stmt: &mut Stmt, state: &mut State, preserve_result: bool) {
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match stmt {
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// var = var op expr => var op= expr
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Stmt::Assignment(x, _)
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if x.1.is_none()
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&& x.0.is_variable_access(true)
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&& matches!(&x.2, Expr::FnCall(x2, _)
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if Token::lookup_from_syntax(&x2.name).map(|t| t.has_op_assignment()).unwrap_or(false)
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&& x2.args_count() == 2 && x2.args.len() >= 1
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&& x2.args[0].get_variable_name(true) == x.0.get_variable_name(true)
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) =>
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{
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match &mut x.2 {
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Expr::FnCall(x2, _) => {
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state.set_dirty();
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let op = Token::lookup_from_syntax(&x2.name).unwrap();
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let op_assignment = op.make_op_assignment().unwrap();
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x.1 = Some(OpAssignment::new(op_assignment));
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x.2 = if x2.args.len() > 1 {
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mem::take(&mut x2.args[1])
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} else {
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let (value, pos) = mem::take(&mut x2.literal_args[0]);
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Expr::DynamicConstant(Box::new(value), pos)
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};
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}
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_ => unreachable!(),
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}
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}
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// expr op= expr
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Stmt::Assignment(x, _) => match x.0 {
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Expr::Variable(_, _, _) => optimize_expr(&mut x.2, state, false),
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_ => {
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optimize_expr(&mut x.0, state, false);
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optimize_expr(&mut x.2, state, false);
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}
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},
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// if expr {}
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Stmt::If(condition, x, _) if x.0.is_empty() && x.1.is_empty() => {
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state.set_dirty();
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let pos = condition.position();
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let mut expr = mem::take(condition);
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optimize_expr(&mut expr, state, false);
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*stmt = if preserve_result {
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// -> { expr, Noop }
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Stmt::Block(Box::new([Stmt::Expr(expr), Stmt::Noop(pos)]), pos)
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} else {
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// -> expr
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Stmt::Expr(expr)
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};
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}
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// if false { if_block } -> Noop
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Stmt::If(Expr::BoolConstant(false, pos), x, _) if x.1.is_empty() => {
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state.set_dirty();
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*stmt = Stmt::Noop(*pos);
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}
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// if false { if_block } else { else_block } -> else_block
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Stmt::If(Expr::BoolConstant(false, _), x, _) => {
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state.set_dirty();
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let else_block = mem::take(&mut *x.1).into_vec();
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*stmt = match optimize_stmt_block(else_block, state, preserve_result, true, false) {
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statements if statements.is_empty() => Stmt::Noop(x.1.position()),
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statements => Stmt::Block(statements.into_boxed_slice(), x.1.position()),
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}
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}
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// if true { if_block } else { else_block } -> if_block
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Stmt::If(Expr::BoolConstant(true, _), x, _) => {
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state.set_dirty();
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let if_block = mem::take(&mut *x.0).into_vec();
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*stmt = match optimize_stmt_block(if_block, state, preserve_result, true, false) {
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statements if statements.is_empty() => Stmt::Noop(x.0.position()),
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statements => Stmt::Block(statements.into_boxed_slice(), x.0.position()),
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}
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}
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// if expr { if_block } else { else_block }
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Stmt::If(condition, x, _) => {
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optimize_expr(condition, state, false);
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let if_block = mem::take(x.0.statements()).into_vec();
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*x.0.statements() =
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optimize_stmt_block(if_block, state, preserve_result, true, false).into();
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let else_block = mem::take(x.1.statements()).into_vec();
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*x.1.statements() =
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optimize_stmt_block(else_block, state, preserve_result, true, false).into();
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}
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|
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// switch const { ... }
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Stmt::Switch(match_expr, x, pos) if match_expr.is_constant() => {
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let value = match_expr.get_constant_value().unwrap();
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let hasher = &mut get_hasher();
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value.hash(hasher);
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let hash = hasher.finish();
|
|
|
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state.set_dirty();
|
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let table = &mut x.0;
|
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|
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if let Some(block) = table.get_mut(&hash) {
|
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if let Some(mut condition) = mem::take(&mut block.0) {
|
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// switch const { case if condition => stmt, _ => def } => if condition { stmt } else { def }
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optimize_expr(&mut condition, state, false);
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let def_block = mem::take(&mut *x.1).into_vec();
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let def_stmt = optimize_stmt_block(def_block, state, true, true, false);
|
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let def_pos = if x.1.position().is_none() {
|
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*pos
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} else {
|
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x.1.position()
|
|
};
|
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|
|
*stmt = Stmt::If(
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condition,
|
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Box::new((
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mem::take(&mut block.1),
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Stmt::Block(def_stmt.into_boxed_slice(), def_pos).into(),
|
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)),
|
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match_expr.position(),
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);
|
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} else {
|
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// Promote the matched case
|
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let new_pos = block.1.position();
|
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let statements = mem::take(&mut *block.1);
|
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let statements =
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optimize_stmt_block(statements.into_vec(), state, true, true, false);
|
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*stmt = Stmt::Block(statements.into_boxed_slice(), new_pos);
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}
|
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} else {
|
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// Promote the default case
|
|
let def_block = mem::take(&mut *x.1).into_vec();
|
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let def_stmt = optimize_stmt_block(def_block, state, true, true, false);
|
|
let def_pos = if x.1.position().is_none() {
|
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*pos
|
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} else {
|
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x.1.position()
|
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};
|
|
*stmt = Stmt::Block(def_stmt.into_boxed_slice(), def_pos);
|
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}
|
|
}
|
|
// switch
|
|
Stmt::Switch(match_expr, x, _) => {
|
|
optimize_expr(match_expr, state, false);
|
|
x.0.values_mut().for_each(|block| {
|
|
let condition = mem::take(&mut block.0).map_or_else(
|
|
|| Expr::Unit(Position::NONE),
|
|
|mut condition| {
|
|
optimize_expr(&mut condition, state, false);
|
|
condition
|
|
},
|
|
);
|
|
|
|
match condition {
|
|
Expr::Unit(_) | Expr::BoolConstant(true, _) => (),
|
|
_ => {
|
|
block.0 = Some(condition);
|
|
|
|
*block.1.statements() = optimize_stmt_block(
|
|
mem::take(block.1.statements()).into_vec(),
|
|
state,
|
|
preserve_result,
|
|
true,
|
|
false,
|
|
)
|
|
.into();
|
|
}
|
|
}
|
|
});
|
|
|
|
// Remove false cases
|
|
while let Some((&key, _)) = x.0.iter().find(|(_, block)| match block.0 {
|
|
Some(Expr::BoolConstant(false, _)) => true,
|
|
_ => false,
|
|
}) {
|
|
state.set_dirty();
|
|
x.0.remove(&key);
|
|
}
|
|
|
|
let def_block = mem::take(x.1.statements()).into_vec();
|
|
*x.1.statements() =
|
|
optimize_stmt_block(def_block, state, preserve_result, true, false).into();
|
|
}
|
|
|
|
// while false { block } -> Noop
|
|
Stmt::While(Expr::BoolConstant(false, pos), _, _) => {
|
|
state.set_dirty();
|
|
*stmt = Stmt::Noop(*pos)
|
|
}
|
|
// while expr { block }
|
|
Stmt::While(condition, body, _) => {
|
|
optimize_expr(condition, state, false);
|
|
let block = mem::take(body.statements()).into_vec();
|
|
*body.statements() = optimize_stmt_block(block, state, false, true, false).into();
|
|
|
|
if body.len() == 1 {
|
|
match body[0] {
|
|
// while expr { break; } -> { expr; }
|
|
Stmt::Break(pos) => {
|
|
// Only a single break statement - turn into running the guard expression once
|
|
state.set_dirty();
|
|
if !condition.is_unit() {
|
|
let mut statements = vec![Stmt::Expr(mem::take(condition))];
|
|
if preserve_result {
|
|
statements.push(Stmt::Noop(pos))
|
|
}
|
|
*stmt = Stmt::Block(statements.into_boxed_slice(), pos);
|
|
} else {
|
|
*stmt = Stmt::Noop(pos);
|
|
};
|
|
}
|
|
_ => (),
|
|
}
|
|
}
|
|
}
|
|
// do { block } while false | do { block } until true -> { block }
|
|
Stmt::Do(body, Expr::BoolConstant(true, _), false, _)
|
|
| Stmt::Do(body, Expr::BoolConstant(false, _), true, _) => {
|
|
state.set_dirty();
|
|
let block_pos = body.position();
|
|
let block = mem::take(body.statements()).into_vec();
|
|
*stmt = Stmt::Block(
|
|
optimize_stmt_block(block, state, false, true, false).into_boxed_slice(),
|
|
block_pos,
|
|
);
|
|
}
|
|
// do { block } while|until expr
|
|
Stmt::Do(body, condition, _, _) => {
|
|
optimize_expr(condition, state, false);
|
|
let block = mem::take(body.statements()).into_vec();
|
|
*body.statements() = optimize_stmt_block(block, state, false, true, false).into();
|
|
}
|
|
// for id in expr { block }
|
|
Stmt::For(iterable, x, _) => {
|
|
optimize_expr(iterable, state, false);
|
|
let body = mem::take(x.2.statements()).into_vec();
|
|
*x.2.statements() = optimize_stmt_block(body, state, false, true, false).into();
|
|
}
|
|
// let id = expr;
|
|
Stmt::Let(expr, _, _, _) => optimize_expr(expr, state, false),
|
|
// import expr as var;
|
|
#[cfg(not(feature = "no_module"))]
|
|
Stmt::Import(expr, _, _) => optimize_expr(expr, state, false),
|
|
// { block }
|
|
Stmt::Block(statements, pos) => {
|
|
let statements = mem::take(statements).into_vec();
|
|
let mut block = optimize_stmt_block(statements, state, preserve_result, true, false);
|
|
|
|
match block.as_mut_slice() {
|
|
[] => {
|
|
state.set_dirty();
|
|
*stmt = Stmt::Noop(*pos);
|
|
}
|
|
// Only one statement - promote
|
|
[s] => {
|
|
state.set_dirty();
|
|
*stmt = mem::take(s);
|
|
}
|
|
_ => *stmt = Stmt::Block(block.into_boxed_slice(), *pos),
|
|
}
|
|
}
|
|
// try { pure try_block } catch ( var ) { catch_block } -> try_block
|
|
Stmt::TryCatch(x, _, _) if x.0.iter().all(Stmt::is_pure) => {
|
|
// If try block is pure, there will never be any exceptions
|
|
state.set_dirty();
|
|
let try_pos = x.0.position();
|
|
let try_block = mem::take(&mut *x.0).into_vec();
|
|
*stmt = Stmt::Block(
|
|
optimize_stmt_block(try_block, state, false, true, false).into_boxed_slice(),
|
|
try_pos,
|
|
);
|
|
}
|
|
// try { try_block } catch ( var ) { catch_block }
|
|
Stmt::TryCatch(x, _, _) => {
|
|
let try_block = mem::take(x.0.statements()).into_vec();
|
|
*x.0.statements() = optimize_stmt_block(try_block, state, false, true, false).into();
|
|
let catch_block = mem::take(x.2.statements()).into_vec();
|
|
*x.2.statements() = optimize_stmt_block(catch_block, state, false, true, false).into();
|
|
}
|
|
// func(...)
|
|
Stmt::Expr(expr @ Expr::FnCall(_, _)) => {
|
|
optimize_expr(expr, state, false);
|
|
match expr {
|
|
Expr::FnCall(x, pos) => {
|
|
state.set_dirty();
|
|
*stmt = Stmt::FnCall(mem::take(x), *pos);
|
|
}
|
|
_ => (),
|
|
}
|
|
}
|
|
// {}
|
|
Stmt::Expr(Expr::Stmt(x)) if x.is_empty() => {
|
|
state.set_dirty();
|
|
*stmt = Stmt::Noop(x.position());
|
|
}
|
|
// {...};
|
|
Stmt::Expr(Expr::Stmt(x)) => {
|
|
state.set_dirty();
|
|
*stmt = mem::take(x.as_mut()).into();
|
|
}
|
|
// expr;
|
|
Stmt::Expr(expr) => optimize_expr(expr, state, false),
|
|
// return expr;
|
|
Stmt::Return(_, Some(ref mut expr), _) => optimize_expr(expr, state, false),
|
|
|
|
// All other statements - skip
|
|
_ => (),
|
|
}
|
|
}
|
|
|
|
/// Optimize an [expression][Expr].
|
|
fn optimize_expr(expr: &mut Expr, state: &mut State, _chaining: bool) {
|
|
// These keywords are handled specially
|
|
const DONT_EVAL_KEYWORDS: &[&str] = &[
|
|
KEYWORD_PRINT, // side effects
|
|
KEYWORD_DEBUG, // side effects
|
|
KEYWORD_EVAL, // arbitrary scripts
|
|
];
|
|
|
|
match expr {
|
|
// {}
|
|
Expr::Stmt(x) if x.is_empty() => { state.set_dirty(); *expr = Expr::Unit(x.position()) }
|
|
// { stmt; ... } - do not count promotion as dirty because it gets turned back into an array
|
|
Expr::Stmt(x) => {
|
|
*x.statements() = optimize_stmt_block(mem::take(x.statements()).into_vec(), state, true, true, false).into();
|
|
|
|
// { Stmt(Expr) } - promote
|
|
match x.as_mut().as_mut() {
|
|
[ Stmt::Expr(e) ] => { state.set_dirty(); *expr = mem::take(e); }
|
|
_ => ()
|
|
}
|
|
}
|
|
// lhs.rhs
|
|
#[cfg(not(feature = "no_object"))]
|
|
Expr::Dot(x, _) if !_chaining => match (&mut x.lhs, &mut x.rhs) {
|
|
// map.string
|
|
(Expr::Map(m, pos), Expr::Property(p)) if m.0.iter().all(|(_, x)| x.is_pure()) => {
|
|
let prop = p.2.0.as_str();
|
|
// Map literal where everything is pure - promote the indexed item.
|
|
// All other items can be thrown away.
|
|
state.set_dirty();
|
|
*expr = mem::take(&mut m.0).into_iter().find(|(x, _)| &x.name == prop)
|
|
.map(|(_, mut expr)| { expr.set_position(*pos); expr })
|
|
.unwrap_or_else(|| Expr::Unit(*pos));
|
|
}
|
|
// var.rhs
|
|
(Expr::Variable(_, _, _), rhs) => optimize_expr(rhs, state, true),
|
|
// lhs.rhs
|
|
(lhs, rhs) => { optimize_expr(lhs, state, false); optimize_expr(rhs, state, true); }
|
|
}
|
|
// ....lhs.rhs
|
|
#[cfg(not(feature = "no_object"))]
|
|
Expr::Dot(x, _) => { optimize_expr(&mut x.lhs, state, false); optimize_expr(&mut x.rhs, state, _chaining); }
|
|
|
|
// lhs[rhs]
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Index(x, _) if !_chaining => match (&mut x.lhs, &mut x.rhs) {
|
|
// array[int]
|
|
(Expr::Array(a, pos), Expr::IntegerConstant(i, _))
|
|
if *i >= 0 && (*i as usize) < a.len() && a.iter().all(Expr::is_pure) =>
|
|
{
|
|
// Array literal where everything is pure - promote the indexed item.
|
|
// All other items can be thrown away.
|
|
state.set_dirty();
|
|
let mut result = a.remove(*i as usize);
|
|
result.set_position(*pos);
|
|
*expr = result;
|
|
}
|
|
// array[-int]
|
|
(Expr::Array(a, pos), Expr::IntegerConstant(i, _))
|
|
if *i < 0 && i.checked_abs().map(|n| n as usize <= a.len()).unwrap_or(false) && a.iter().all(Expr::is_pure) =>
|
|
{
|
|
// Array literal where everything is pure - promote the indexed item.
|
|
// All other items can be thrown away.
|
|
state.set_dirty();
|
|
let mut result = a.remove(a.len() - i.abs() as usize);
|
|
result.set_position(*pos);
|
|
*expr = result;
|
|
}
|
|
// map[string]
|
|
(Expr::Map(m, pos), Expr::StringConstant(s, _)) if m.0.iter().all(|(_, x)| x.is_pure()) => {
|
|
// Map literal where everything is pure - promote the indexed item.
|
|
// All other items can be thrown away.
|
|
state.set_dirty();
|
|
*expr = mem::take(&mut m.0).into_iter().find(|(x, _)| x.name.as_str() == s.as_str())
|
|
.map(|(_, mut expr)| { expr.set_position(*pos); expr })
|
|
.unwrap_or_else(|| Expr::Unit(*pos));
|
|
}
|
|
// int[int]
|
|
(Expr::IntegerConstant(n, pos), Expr::IntegerConstant(i, _)) if *i >= 0 && (*i as usize) < (std::mem::size_of_val(n) * 8) => {
|
|
// Bit-field literal indexing - get the bit
|
|
state.set_dirty();
|
|
*expr = Expr::BoolConstant((*n & (1 << (*i as usize))) != 0, *pos);
|
|
}
|
|
// int[-int]
|
|
(Expr::IntegerConstant(n, pos), Expr::IntegerConstant(i, _)) if *i < 0 && i.checked_abs().map(|i| i as usize <= (std::mem::size_of_val(n) * 8)).unwrap_or(false) => {
|
|
// Bit-field literal indexing - get the bit
|
|
state.set_dirty();
|
|
*expr = Expr::BoolConstant((*n & (1 << (std::mem::size_of_val(n) * 8 - i.abs() as usize))) != 0, *pos);
|
|
}
|
|
// string[int]
|
|
(Expr::StringConstant(s, pos), Expr::IntegerConstant(i, _)) if *i >= 0 && (*i as usize) < s.chars().count() => {
|
|
// String literal indexing - get the character
|
|
state.set_dirty();
|
|
*expr = Expr::CharConstant(s.chars().nth(*i as usize).unwrap(), *pos);
|
|
}
|
|
// string[-int]
|
|
(Expr::StringConstant(s, pos), Expr::IntegerConstant(i, _)) if *i < 0 && i.checked_abs().map(|n| n as usize <= s.chars().count()).unwrap_or(false) => {
|
|
// String literal indexing - get the character
|
|
state.set_dirty();
|
|
*expr = Expr::CharConstant(s.chars().rev().nth(i.abs() as usize - 1).unwrap(), *pos);
|
|
}
|
|
// var[rhs]
|
|
(Expr::Variable(_, _, _), rhs) => optimize_expr(rhs, state, true),
|
|
// lhs[rhs]
|
|
(lhs, rhs) => { optimize_expr(lhs, state, false); optimize_expr(rhs, state, true); }
|
|
},
|
|
// ...[lhs][rhs]
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Index(x, _) => { optimize_expr(&mut x.lhs, state, false); optimize_expr(&mut x.rhs, state, _chaining); }
|
|
// ``
|
|
Expr::InterpolatedString(x) if x.is_empty() => {
|
|
state.set_dirty();
|
|
*expr = Expr::StringConstant(state.engine.empty_string.clone(), Position::NONE);
|
|
}
|
|
// `...`
|
|
Expr::InterpolatedString(x) if x.len() == 1 && matches!(x[0], Expr::StringConstant(_, _)) => {
|
|
state.set_dirty();
|
|
*expr = mem::take(&mut x[0]);
|
|
}
|
|
// `... ${ ... } ...`
|
|
Expr::InterpolatedString(x) => {
|
|
x.iter_mut().for_each(|expr| optimize_expr(expr, state, false));
|
|
|
|
let mut n= 0;
|
|
|
|
// Merge consecutive strings
|
|
while n < x.len()-1 {
|
|
match (mem::take(&mut x[n]), mem::take(&mut x[n+1])) {
|
|
(Expr::StringConstant(mut s1, pos), Expr::StringConstant(s2, _)) => {
|
|
s1 += s2;
|
|
x[n] = Expr::StringConstant(s1, pos);
|
|
x.remove(n+1);
|
|
state.set_dirty();
|
|
}
|
|
(expr1, Expr::Unit(_)) => {
|
|
x[n] = expr1;
|
|
x.remove(n+1);
|
|
state.set_dirty();
|
|
}
|
|
(Expr::Unit(_), expr2) => {
|
|
x[n+1] = expr2;
|
|
x.remove(n);
|
|
state.set_dirty();
|
|
}
|
|
(expr1, Expr::StringConstant(s, _)) if s.is_empty() => {
|
|
x[n] = expr1;
|
|
x.remove(n+1);
|
|
state.set_dirty();
|
|
}
|
|
(Expr::StringConstant(s, _), expr2) if s.is_empty()=> {
|
|
x[n+1] = expr2;
|
|
x.remove(n);
|
|
state.set_dirty();
|
|
}
|
|
(expr1, expr2) => {
|
|
x[n] = expr1;
|
|
x[n+1] = expr2;
|
|
n += 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
x.shrink_to_fit();
|
|
}
|
|
// [ constant .. ]
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Array(_, _) if expr.is_constant() => {
|
|
state.set_dirty();
|
|
*expr = Expr::DynamicConstant(Box::new(expr.get_constant_value().unwrap()), expr.position());
|
|
}
|
|
// [ items .. ]
|
|
#[cfg(not(feature = "no_index"))]
|
|
Expr::Array(x, _) => x.iter_mut().for_each(|expr| optimize_expr(expr, state, false)),
|
|
// #{ key:constant, .. }
|
|
#[cfg(not(feature = "no_object"))]
|
|
Expr::Map(_, _) if expr.is_constant() => {
|
|
state.set_dirty();
|
|
*expr = Expr::DynamicConstant(Box::new(expr.get_constant_value().unwrap()), expr.position());
|
|
}
|
|
// #{ key:value, .. }
|
|
#[cfg(not(feature = "no_object"))]
|
|
Expr::Map(x, _) => x.0.iter_mut().for_each(|(_, expr)| optimize_expr(expr, state, false)),
|
|
// lhs && rhs
|
|
Expr::And(x, _) => match (&mut x.lhs, &mut x.rhs) {
|
|
// true && rhs -> rhs
|
|
(Expr::BoolConstant(true, _), rhs) => {
|
|
state.set_dirty();
|
|
optimize_expr(rhs, state, false);
|
|
*expr = mem::take(rhs);
|
|
}
|
|
// false && rhs -> false
|
|
(Expr::BoolConstant(false, pos), _) => {
|
|
state.set_dirty();
|
|
*expr = Expr::BoolConstant(false, *pos);
|
|
}
|
|
// lhs && true -> lhs
|
|
(lhs, Expr::BoolConstant(true, _)) => {
|
|
state.set_dirty();
|
|
optimize_expr(lhs, state, false);
|
|
*expr = mem::take(lhs);
|
|
}
|
|
// lhs && rhs
|
|
(lhs, rhs) => { optimize_expr(lhs, state, false); optimize_expr(rhs, state, false); }
|
|
},
|
|
// lhs || rhs
|
|
Expr::Or(ref mut x, _) => match (&mut x.lhs, &mut x.rhs) {
|
|
// false || rhs -> rhs
|
|
(Expr::BoolConstant(false, _), rhs) => {
|
|
state.set_dirty();
|
|
optimize_expr(rhs, state, false);
|
|
*expr = mem::take(rhs);
|
|
}
|
|
// true || rhs -> true
|
|
(Expr::BoolConstant(true, pos), _) => {
|
|
state.set_dirty();
|
|
*expr = Expr::BoolConstant(true, *pos);
|
|
}
|
|
// lhs || false
|
|
(lhs, Expr::BoolConstant(false, _)) => {
|
|
state.set_dirty();
|
|
optimize_expr(lhs, state, false);
|
|
*expr = mem::take(lhs);
|
|
}
|
|
// lhs || rhs
|
|
(lhs, rhs) => { optimize_expr(lhs, state, false); optimize_expr(rhs, state, false); }
|
|
},
|
|
|
|
// eval!
|
|
Expr::FnCall(x, _) if x.name == KEYWORD_EVAL => {
|
|
state.propagate_constants = false;
|
|
}
|
|
// Fn
|
|
Expr::FnCall(x, pos)
|
|
if !x.is_qualified() // Non-qualified
|
|
&& state.optimization_level == OptimizationLevel::Simple // simple optimizations
|
|
&& x.args_count() == 1
|
|
&& x.literal_args.len() == 1
|
|
&& x.literal_args[0].0.is::<ImmutableString>()
|
|
&& x.name == KEYWORD_FN_PTR
|
|
=> {
|
|
state.set_dirty();
|
|
let fn_ptr = FnPtr::new_unchecked(mem::take(&mut x.literal_args[0].0).as_str_ref().unwrap().into(), Default::default());
|
|
*expr = Expr::DynamicConstant(Box::new(fn_ptr.into()), *pos);
|
|
}
|
|
|
|
// Do not call some special keywords
|
|
Expr::FnCall(x, _) if DONT_EVAL_KEYWORDS.contains(&x.name.as_ref()) => {
|
|
x.args.iter_mut().for_each(|a| optimize_expr(a, state, false));
|
|
}
|
|
|
|
// Call built-in operators
|
|
Expr::FnCall(x, pos)
|
|
if !x.is_qualified() // Non-qualified
|
|
&& state.optimization_level == OptimizationLevel::Simple // simple optimizations
|
|
&& x.args_count() == 2 // binary call
|
|
&& x.args.iter().all(Expr::is_constant) // all arguments are constants
|
|
//&& !is_valid_identifier(x.name.chars()) // cannot be scripted
|
|
=> {
|
|
let mut arg_values: StaticVec<_> = x.args.iter().map(|e| e.get_constant_value().unwrap())
|
|
.chain(x.literal_args.iter().map(|(v, _)| v).cloned())
|
|
.collect();
|
|
|
|
let arg_types: StaticVec<_> = arg_values.iter().map(Dynamic::type_id).collect();
|
|
|
|
// Search for overloaded operators (can override built-in).
|
|
if !has_native_fn(state, x.hashes.native_hash(), arg_types.as_ref()) {
|
|
if let Some(mut result) = get_builtin_binary_op_fn(x.name.as_ref(), &arg_values[0], &arg_values[1])
|
|
.and_then(|f| {
|
|
let ctx = (state.engine, x.name.as_ref(), state.lib).into();
|
|
let (first, second) = arg_values.split_first_mut().unwrap();
|
|
(f)(ctx, &mut [ first, &mut second[0] ]).ok()
|
|
})
|
|
.map(Expr::from)
|
|
{
|
|
state.set_dirty();
|
|
result.set_position(*pos);
|
|
*expr = result;
|
|
return;
|
|
}
|
|
}
|
|
|
|
x.args.iter_mut().for_each(|a| optimize_expr(a, state, false));
|
|
|
|
// Move constant arguments to the right
|
|
while x.args.last().map(Expr::is_constant).unwrap_or(false) {
|
|
let arg = x.args.pop().unwrap();
|
|
let arg_pos = arg.position();
|
|
x.literal_args.insert(0, (arg.get_constant_value().unwrap(), arg_pos));
|
|
}
|
|
|
|
x.args.shrink_to_fit();
|
|
x.literal_args.shrink_to_fit();
|
|
}
|
|
|
|
// Eagerly call functions
|
|
Expr::FnCall(x, pos)
|
|
if !x.is_qualified() // Non-qualified
|
|
&& state.optimization_level == OptimizationLevel::Full // full optimizations
|
|
&& x.args.iter().all(Expr::is_constant) // all arguments are constants
|
|
=> {
|
|
// First search for script-defined functions (can override built-in)
|
|
#[cfg(not(feature = "no_function"))]
|
|
let has_script_fn = state.lib.iter().any(|&m| m.get_script_fn(x.name.as_ref(), x.args_count()).is_some());
|
|
#[cfg(feature = "no_function")]
|
|
let has_script_fn = false;
|
|
|
|
if !has_script_fn {
|
|
let mut arg_values: StaticVec<_> = x.args.iter().map(|e| e.get_constant_value().unwrap())
|
|
.chain(x.literal_args.iter().map(|(v, _)| v).cloned())
|
|
.collect();
|
|
|
|
// Save the typename of the first argument if it is `type_of()`
|
|
// This is to avoid `call_args` being passed into the closure
|
|
let arg_for_type_of = if x.name == KEYWORD_TYPE_OF && arg_values.len() == 1 {
|
|
state.engine.map_type_name(arg_values[0].type_name())
|
|
} else {
|
|
""
|
|
};
|
|
|
|
if let Some(mut result) = call_fn_with_constant_arguments(&state, x.name.as_ref(), &mut arg_values)
|
|
.or_else(|| {
|
|
if !arg_for_type_of.is_empty() {
|
|
// Handle `type_of()`
|
|
Some(arg_for_type_of.to_string().into())
|
|
} else {
|
|
None
|
|
}
|
|
})
|
|
.map(Expr::from)
|
|
{
|
|
state.set_dirty();
|
|
result.set_position(*pos);
|
|
*expr = result;
|
|
return;
|
|
}
|
|
}
|
|
|
|
x.args.iter_mut().for_each(|a| optimize_expr(a, state, false));
|
|
}
|
|
|
|
// id(args ..) -> optimize function call arguments
|
|
Expr::FnCall(x, _) => {
|
|
x.args.iter_mut().for_each(|a| optimize_expr(a, state, false));
|
|
|
|
// Move constant arguments to the right
|
|
while x.args.last().map(Expr::is_constant).unwrap_or(false) {
|
|
let arg = x.args.pop().unwrap();
|
|
let arg_pos = arg.position();
|
|
x.literal_args.insert(0, (arg.get_constant_value().unwrap(), arg_pos));
|
|
}
|
|
|
|
x.args.shrink_to_fit();
|
|
x.literal_args.shrink_to_fit();
|
|
}
|
|
|
|
// constant-name
|
|
Expr::Variable(_, pos, x) if x.1.is_none() && state.find_constant(&x.2).is_some() => {
|
|
// Replace constant with value
|
|
let pos = *pos;
|
|
*expr = Expr::from(state.find_constant(&x.2).unwrap().clone());
|
|
expr.set_position(pos);
|
|
state.set_dirty();
|
|
}
|
|
|
|
// Custom syntax
|
|
Expr::Custom(x, _) => {
|
|
if x.scope_changed {
|
|
state.propagate_constants = false;
|
|
}
|
|
x.keywords.iter_mut().for_each(|expr| optimize_expr(expr, state, false));
|
|
}
|
|
|
|
// All other expressions - skip
|
|
_ => (),
|
|
}
|
|
}
|
|
|
|
/// Optimize a block of [statements][Stmt] at top level.
|
|
fn optimize_top_level(
|
|
mut statements: Vec<Stmt>,
|
|
engine: &Engine,
|
|
scope: &Scope,
|
|
lib: &[&Module],
|
|
optimization_level: OptimizationLevel,
|
|
) -> Vec<Stmt> {
|
|
// If optimization level is None then skip optimizing
|
|
if optimization_level == OptimizationLevel::None {
|
|
statements.shrink_to_fit();
|
|
return statements;
|
|
}
|
|
|
|
// Set up the state
|
|
let mut state = State::new(engine, lib, optimization_level);
|
|
|
|
// Add constants and variables from the scope
|
|
scope.iter().for_each(|(name, constant, value)| {
|
|
if !constant {
|
|
state.push_var(name, AccessMode::ReadWrite, None);
|
|
} else {
|
|
state.push_var(name, AccessMode::ReadOnly, Some(value));
|
|
}
|
|
});
|
|
|
|
statements = optimize_stmt_block(statements, &mut state, true, false, true);
|
|
statements
|
|
}
|
|
|
|
/// Optimize an [`AST`].
|
|
pub fn optimize_into_ast(
|
|
engine: &Engine,
|
|
scope: &Scope,
|
|
mut statements: Vec<Stmt>,
|
|
_functions: Vec<crate::Shared<crate::ast::ScriptFnDef>>,
|
|
optimization_level: OptimizationLevel,
|
|
) -> AST {
|
|
let level = if cfg!(feature = "no_optimize") {
|
|
Default::default()
|
|
} else {
|
|
optimization_level
|
|
};
|
|
|
|
#[cfg(not(feature = "no_function"))]
|
|
let lib = {
|
|
let mut module = Module::new();
|
|
|
|
if level != OptimizationLevel::None {
|
|
// We only need the script library's signatures for optimization purposes
|
|
let mut lib2 = Module::new();
|
|
|
|
_functions
|
|
.iter()
|
|
.map(|fn_def| crate::ast::ScriptFnDef {
|
|
name: fn_def.name.clone(),
|
|
access: fn_def.access,
|
|
body: Default::default(),
|
|
params: fn_def.params.clone(),
|
|
#[cfg(not(feature = "no_closure"))]
|
|
externals: fn_def.externals.clone(),
|
|
lib: None,
|
|
#[cfg(not(feature = "no_module"))]
|
|
mods: Default::default(),
|
|
#[cfg(not(feature = "no_function"))]
|
|
#[cfg(feature = "metadata")]
|
|
comments: Default::default(),
|
|
})
|
|
.for_each(|fn_def| {
|
|
lib2.set_script_fn(fn_def);
|
|
});
|
|
|
|
let lib2 = &[&lib2];
|
|
|
|
_functions
|
|
.into_iter()
|
|
.map(|fn_def| {
|
|
let mut fn_def = crate::fn_native::shared_take_or_clone(fn_def);
|
|
|
|
// Optimize the function body
|
|
let state = &mut State::new(engine, lib2, level);
|
|
|
|
let body = mem::take(fn_def.body.statements()).into_vec();
|
|
|
|
*fn_def.body.statements() =
|
|
optimize_stmt_block(body, state, true, true, true).into();
|
|
|
|
fn_def
|
|
})
|
|
.for_each(|fn_def| {
|
|
module.set_script_fn(fn_def);
|
|
});
|
|
} else {
|
|
_functions.into_iter().for_each(|fn_def| {
|
|
module.set_script_fn(fn_def);
|
|
});
|
|
}
|
|
|
|
module
|
|
};
|
|
|
|
#[cfg(feature = "no_function")]
|
|
let lib = Default::default();
|
|
|
|
statements.shrink_to_fit();
|
|
|
|
AST::new(
|
|
match level {
|
|
OptimizationLevel::None => statements,
|
|
OptimizationLevel::Simple | OptimizationLevel::Full => {
|
|
optimize_top_level(statements, engine, &scope, &[&lib], level)
|
|
}
|
|
},
|
|
lib,
|
|
)
|
|
}
|