mirror of
https://github.com/roc-lang/roc.git
synced 2025-09-29 06:44:46 +00:00
perform copy propagation
This commit is contained in:
Folkert
parent
078c6df677
commit
f8143e3e53
4 changed files with 581 additions and 121 deletions
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@ -93,7 +93,6 @@ pub fn occuring_variables_expr(expr: &Expr<'_>, result: &mut MutSet<Symbol>) {
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match expr {
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FunctionPointer(symbol, _)
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| Alias(symbol)
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| AccessAtIndex {
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structure: symbol, ..
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} => {
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@ -239,6 +238,11 @@ impl<'a> Context<'a> {
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return stmt;
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}
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// if this symbol is never a reference, don't emit
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if !info.reference {
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return stmt;
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}
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self.arena.alloc(Stmt::Inc(symbol, stmt))
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}
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@ -250,6 +254,11 @@ impl<'a> Context<'a> {
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return stmt;
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}
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// if this symbol is never a reference, don't emit
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if !info.reference {
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return stmt;
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}
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self.arena.alloc(Stmt::Dec(symbol, stmt))
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}
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@ -424,13 +433,8 @@ impl<'a> Context<'a> {
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),
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AccessAtIndex { structure: x, .. } => {
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let b = self.add_dec_if_needed(x, b, b_live_vars);
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// NOTE deviation from Lean. I think lean assumes all structure elements live on
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// the heap. Therefore any access to a Tag/Struct element must increment its
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// refcount. But in roc, structure elements can be unboxed.
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let info_x = self.get_var_info(x);
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// let info_z = self.get_var_info(z);
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let b = if info_x.consume {
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println!("inc on {}", z);
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self.add_inc(z, b)
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} else {
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b
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@ -489,7 +493,6 @@ impl<'a> Context<'a> {
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self.arena.alloc(Stmt::Let(z, v, l, b))
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}
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Alias(_) => unreachable!("well, it should be unreachable!"),
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EmptyArray | FunctionPointer(_, _) | Literal(_) | RuntimeErrorFunction(_) => {
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// EmptyArray is always stack-allocated
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@ -734,7 +737,8 @@ impl<'a> Context<'a> {
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(switch, case_live_vars)
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}
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_ => todo!(),
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RuntimeError(_) | Inc(_,_) | Dec(_,_) => (stmt, MutSet::default()),
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}
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}
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}
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@ -404,10 +404,6 @@ pub enum CallType {
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pub enum Expr<'a> {
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Literal(Literal<'a>),
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/// A symbol will alias this symbol
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/// in the long term we should get rid of this using copy propagation
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Alias(Symbol),
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// Functions
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FunctionPointer(Symbol, Layout<'a>),
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FunctionCall {
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@ -490,7 +486,6 @@ impl<'a> Expr<'a> {
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match self {
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Literal(lit) => lit.to_doc(alloc),
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Alias(symbol) => alloc.text("alias ").append(symbol_to_doc(alloc, *symbol)),
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FunctionPointer(symbol, _) => symbol_to_doc(alloc, *symbol),
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@ -1049,7 +1044,12 @@ pub fn with_hole<'a>(
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LetNonRec(def, cont, _, _) => {
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// WRONG! this is introduces new control flow, and should call `from_can` again
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if let roc_can::pattern::Pattern::Identifier(symbol) = def.loc_pattern.value {
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let stmt = with_hole(env, cont.value, procs, layout_cache, assigned, hole);
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let mut stmt = with_hole(env, cont.value, procs, layout_cache, assigned, hole);
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// this is an alias of a variable
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if let roc_can::expr::Expr::Var(original) = def.loc_expr.value {
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substitute_in_exprs(env.arena, &mut stmt, symbol, original);
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}
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with_hole(
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env,
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@ -1060,7 +1060,51 @@ pub fn with_hole<'a>(
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env.arena.alloc(stmt),
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)
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} else {
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todo!()
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// this may be a destructure pattern
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let mono_pattern = from_can_pattern(env, layout_cache, &def.loc_pattern.value);
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if let Pattern::Identifier(symbol) = mono_pattern {
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let hole = env
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.arena
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.alloc(from_can(env, cont.value, procs, layout_cache));
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with_hole(env, def.loc_expr.value, procs, layout_cache, symbol, hole)
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} else {
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let context = crate::exhaustive::Context::BadDestruct;
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match crate::exhaustive::check(
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def.loc_pattern.region,
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&[(
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Located::at(def.loc_pattern.region, mono_pattern.clone()),
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crate::exhaustive::Guard::NoGuard,
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)],
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context,
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) {
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Ok(_) => {}
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Err(errors) => {
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for error in errors {
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env.problems.push(MonoProblem::PatternProblem(error))
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}
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} // TODO make all variables bound in the pattern evaluate to a runtime error
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// return Stmt::RuntimeError("TODO non-exhaustive pattern");
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}
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// convert the continuation
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let mut stmt = from_can(env, cont.value, procs, layout_cache);
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let outer_symbol = env.unique_symbol();
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stmt =
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store_pattern(env, procs, layout_cache, &mono_pattern, outer_symbol, stmt)
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.unwrap();
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// convert the def body, store in outer_symbol
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with_hole(
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env,
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def.loc_expr.value,
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procs,
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layout_cache,
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outer_symbol,
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env.arena.alloc(stmt),
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)
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}
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}
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}
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Var(symbol) => {
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@ -1840,24 +1884,12 @@ pub fn from_can<'a>(
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// return Stmt::RuntimeError("TODO non-exhaustive pattern");
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}
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let layout = layout_cache
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.from_var(env.arena, def.expr_var, env.subs)
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.expect("invalid layout");
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// convert the continuation
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let mut stmt = from_can(env, cont.value, procs, layout_cache);
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let outer_symbol = env.unique_symbol();
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stmt = store_pattern(
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env,
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procs,
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layout_cache,
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&mono_pattern,
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outer_symbol,
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layout,
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stmt,
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)
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.unwrap();
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stmt = store_pattern(env, procs, layout_cache, &mono_pattern, outer_symbol, stmt)
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.unwrap();
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// convert the def body, store in outer_symbol
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with_hole(
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@ -2012,15 +2044,7 @@ fn from_can_when<'a>(
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let guard_stmt = with_hole(env, loc_expr.value, procs, layout_cache, symbol, jump);
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match store_pattern(
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env,
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procs,
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layout_cache,
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&pattern,
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cond_symbol,
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cond_layout.clone(),
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guard_stmt,
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) {
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match store_pattern(env, procs, layout_cache, &pattern, cond_symbol, guard_stmt) {
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Ok(new_guard_stmt) => (
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pattern,
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Guard::Guard {
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@ -2037,15 +2061,7 @@ fn from_can_when<'a>(
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),
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}
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} else {
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match store_pattern(
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env,
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procs,
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layout_cache,
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&pattern,
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cond_symbol,
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cond_layout.clone(),
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branch_stmt,
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) {
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match store_pattern(env, procs, layout_cache, &pattern, cond_symbol, branch_stmt) {
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Ok(new_branch_stmt) => (pattern, Guard::NoGuard, new_branch_stmt),
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Err(msg) => (
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Pattern::Underscore,
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@ -2068,6 +2084,363 @@ fn from_can_when<'a>(
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)
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}
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fn substitute(substitutions: &MutMap<Symbol, Symbol>, s: Symbol) -> Option<Symbol> {
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match substitutions.get(&s) {
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Some(new) => {
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debug_assert!(!substitutions.contains_key(new));
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Some(*new)
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}
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None => None,
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}
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}
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fn substitute_in_exprs<'a>(arena: &'a Bump, stmt: &mut Stmt<'a>, from: Symbol, to: Symbol) {
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let mut subs = MutMap::default();
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subs.insert(from, to);
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// TODO clean this up
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let ref_stmt = arena.alloc(stmt.clone());
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if let Some(new) = substitute_in_stmt_help(arena, ref_stmt, &subs) {
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*stmt = new.clone();
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}
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}
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fn substitute_in_stmt_help<'a>(
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arena: &'a Bump,
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stmt: &'a Stmt<'a>,
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subs: &MutMap<Symbol, Symbol>,
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) -> Option<&'a Stmt<'a>> {
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use Stmt::*;
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match stmt {
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Let(symbol, expr, layout, cont) => {
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let opt_cont = substitute_in_stmt_help(arena, cont, subs);
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let opt_expr = substitute_in_expr(arena, expr, subs);
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if opt_expr.is_some() || opt_cont.is_some() {
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let cont = opt_cont.unwrap_or(cont);
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let expr = opt_expr.unwrap_or_else(|| expr.clone());
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Some(arena.alloc(Let(*symbol, expr, layout.clone(), cont)))
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} else {
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None
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}
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}
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Join {
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id,
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parameters,
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remainder,
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continuation,
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} => {
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let opt_remainder = substitute_in_stmt_help(arena, remainder, subs);
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let opt_continuation = substitute_in_stmt_help(arena, continuation, subs);
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if opt_remainder.is_some() || opt_continuation.is_some() {
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let remainder = opt_remainder.unwrap_or(remainder);
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let continuation = opt_continuation.unwrap_or_else(|| *continuation);
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Some(arena.alloc(Join {
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id: *id,
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parameters,
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remainder,
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continuation,
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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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Cond {
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cond_symbol,
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cond_layout,
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branching_symbol,
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branching_layout,
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pass,
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fail,
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ret_layout,
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} => {
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let opt_pass = substitute_in_stmt_help(arena, pass, subs);
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let opt_fail = substitute_in_stmt_help(arena, fail, subs);
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if opt_pass.is_some() || opt_fail.is_some() {
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let pass = opt_pass.unwrap_or(pass);
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let fail = opt_fail.unwrap_or_else(|| *fail);
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Some(arena.alloc(Cond {
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cond_symbol: *cond_symbol,
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cond_layout: cond_layout.clone(),
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branching_symbol: *branching_symbol,
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branching_layout: branching_layout.clone(),
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pass,
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fail,
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ret_layout: ret_layout.clone(),
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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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Switch {
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cond_symbol,
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cond_layout,
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branches,
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default_branch,
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ret_layout,
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} => {
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let opt_default = substitute_in_stmt_help(arena, default_branch, subs);
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let mut did_change = false;
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let opt_branches = Vec::from_iter_in(
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branches.iter().map(|(label, branch)| {
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match substitute_in_stmt_help(arena, branch, subs) {
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None => None,
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Some(branch) => {
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did_change = true;
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Some((*label, branch.clone()))
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}
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}
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}),
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arena,
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);
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if opt_default.is_some() || did_change {
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let default_branch = opt_default.unwrap_or(default_branch);
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let branches = if did_change {
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let new = Vec::from_iter_in(
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opt_branches.into_iter().zip(branches.iter()).map(
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|(opt_branch, branch)| match opt_branch {
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None => branch.clone(),
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Some(new_branch) => new_branch,
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},
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),
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arena,
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);
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new.into_bump_slice()
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} else {
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branches
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};
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Some(arena.alloc(Switch {
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cond_symbol: *cond_symbol,
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cond_layout: cond_layout.clone(),
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default_branch,
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branches,
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ret_layout: ret_layout.clone(),
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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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Ret(s) => match substitute(subs, *s) {
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Some(s) => Some(arena.alloc(Ret(s))),
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None => None,
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},
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Inc(symbol, cont) => match substitute_in_stmt_help(arena, cont, subs) {
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Some(cont) => Some(arena.alloc(Inc(*symbol, cont))),
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None => None,
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},
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Dec(symbol, cont) => match substitute_in_stmt_help(arena, cont, subs) {
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Some(cont) => Some(arena.alloc(Dec(*symbol, cont))),
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None => None,
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},
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Jump(id, args) => {
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let mut did_change = false;
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let new_args = Vec::from_iter_in(
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args.iter().map(|s| match substitute(subs, *s) {
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None => *s,
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Some(s) => {
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did_change = true;
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s
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}
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}),
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arena,
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);
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if did_change {
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let args = new_args.into_bump_slice();
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Some(arena.alloc(Jump(*id, args)))
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} else {
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None
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}
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}
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RuntimeError(_) => None,
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}
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}
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fn substitute_in_expr<'a>(
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arena: &'a Bump,
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expr: &'a Expr<'a>,
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subs: &MutMap<Symbol, Symbol>,
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) -> Option<Expr<'a>> {
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use Expr::*;
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match expr {
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Literal(_) | FunctionPointer(_, _) | EmptyArray | RuntimeErrorFunction(_) => None,
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FunctionCall {
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call_type,
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args,
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arg_layouts,
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layout,
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} => {
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let opt_call_type = match call_type {
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CallType::ByName(s) => substitute(subs, *s).map(CallType::ByName),
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CallType::ByPointer(s) => substitute(subs, *s).map(CallType::ByPointer),
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};
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let mut did_change = false;
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let new_args = Vec::from_iter_in(
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args.iter().map(|s| match substitute(subs, *s) {
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None => *s,
|
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Some(s) => {
|
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did_change = true;
|
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s
|
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}
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}),
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arena,
|
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);
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|
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if did_change || opt_call_type.is_some() {
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let call_type = opt_call_type.unwrap_or(*call_type);
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let args = new_args.into_bump_slice();
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|
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Some(FunctionCall {
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call_type,
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args,
|
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arg_layouts: *arg_layouts,
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layout: layout.clone(),
|
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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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RunLowLevel(op, args) => {
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let mut did_change = false;
|
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let new_args = Vec::from_iter_in(
|
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args.iter().map(|s| match substitute(subs, *s) {
|
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None => *s,
|
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Some(s) => {
|
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did_change = true;
|
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s
|
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}
|
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}),
|
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arena,
|
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);
|
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|
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if did_change {
|
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let args = new_args.into_bump_slice();
|
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|
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Some(RunLowLevel(*op, args))
|
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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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Tag {
|
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tag_layout,
|
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tag_name,
|
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tag_id,
|
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union_size,
|
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arguments: args,
|
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} => {
|
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let mut did_change = false;
|
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let new_args = Vec::from_iter_in(
|
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args.iter().map(|s| match substitute(subs, *s) {
|
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None => *s,
|
||||
Some(s) => {
|
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did_change = true;
|
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s
|
||||
}
|
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}),
|
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arena,
|
||||
);
|
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|
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if did_change {
|
||||
let arguments = new_args.into_bump_slice();
|
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|
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Some(Tag {
|
||||
tag_layout: tag_layout.clone(),
|
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tag_name: tag_name.clone(),
|
||||
tag_id: *tag_id,
|
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union_size: *union_size,
|
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arguments,
|
||||
})
|
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} else {
|
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None
|
||||
}
|
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}
|
||||
Struct(args) => {
|
||||
let mut did_change = false;
|
||||
let new_args = Vec::from_iter_in(
|
||||
args.iter().map(|s| match substitute(subs, *s) {
|
||||
None => *s,
|
||||
Some(s) => {
|
||||
did_change = true;
|
||||
s
|
||||
}
|
||||
}),
|
||||
arena,
|
||||
);
|
||||
|
||||
if did_change {
|
||||
let args = new_args.into_bump_slice();
|
||||
|
||||
Some(Struct(args))
|
||||
} else {
|
||||
None
|
||||
}
|
||||
}
|
||||
|
||||
Array {
|
||||
elems: args,
|
||||
elem_layout,
|
||||
} => {
|
||||
let mut did_change = false;
|
||||
let new_args = Vec::from_iter_in(
|
||||
args.iter().map(|s| match substitute(subs, *s) {
|
||||
None => *s,
|
||||
Some(s) => {
|
||||
did_change = true;
|
||||
s
|
||||
}
|
||||
}),
|
||||
arena,
|
||||
);
|
||||
|
||||
if did_change {
|
||||
let args = new_args.into_bump_slice();
|
||||
|
||||
Some(Array {
|
||||
elem_layout: elem_layout.clone(),
|
||||
elems: args,
|
||||
})
|
||||
} else {
|
||||
None
|
||||
}
|
||||
}
|
||||
|
||||
AccessAtIndex {
|
||||
index,
|
||||
structure,
|
||||
field_layouts,
|
||||
is_unwrapped,
|
||||
} => match substitute(subs, *structure) {
|
||||
Some(structure) => Some(AccessAtIndex {
|
||||
index: *index,
|
||||
field_layouts: *field_layouts,
|
||||
is_unwrapped: *is_unwrapped,
|
||||
structure,
|
||||
}),
|
||||
None => None,
|
||||
},
|
||||
}
|
||||
}
|
||||
|
||||
#[allow(clippy::too_many_arguments)]
|
||||
fn store_pattern<'a>(
|
||||
env: &mut Env<'a, '_>,
|
||||
|
|
@ -2075,15 +2448,13 @@ fn store_pattern<'a>(
|
|||
layout_cache: &mut LayoutCache<'a>,
|
||||
can_pat: &Pattern<'a>,
|
||||
outer_symbol: Symbol,
|
||||
layout: Layout<'a>,
|
||||
mut stmt: Stmt<'a>,
|
||||
) -> Result<Stmt<'a>, &'a str> {
|
||||
use Pattern::*;
|
||||
|
||||
match can_pat {
|
||||
Identifier(symbol) => {
|
||||
let expr = Expr::Alias(outer_symbol);
|
||||
stmt = Stmt::Let(*symbol, expr, layout, env.arena.alloc(stmt));
|
||||
substitute_in_exprs(env.arena, &mut stmt, *symbol, outer_symbol);
|
||||
}
|
||||
Underscore => {
|
||||
// do nothing
|
||||
|
|
@ -2134,15 +2505,7 @@ fn store_pattern<'a>(
|
|||
let symbol = env.unique_symbol();
|
||||
|
||||
// first recurse, continuing to unpack symbol
|
||||
stmt = store_pattern(
|
||||
env,
|
||||
procs,
|
||||
layout_cache,
|
||||
argument,
|
||||
symbol,
|
||||
arg_layout.clone(),
|
||||
stmt,
|
||||
)?;
|
||||
stmt = store_pattern(env, procs, layout_cache, argument, symbol, stmt)?;
|
||||
|
||||
// then store the symbol
|
||||
stmt = Stmt::Let(symbol, load, arg_layout.clone(), env.arena.alloc(stmt));
|
||||
|
|
@ -2244,15 +2607,7 @@ fn store_record_destruct<'a>(
|
|||
_ => {
|
||||
let symbol = env.unique_symbol();
|
||||
|
||||
stmt = store_pattern(
|
||||
env,
|
||||
procs,
|
||||
layout_cache,
|
||||
guard_pattern,
|
||||
symbol,
|
||||
destruct.layout.clone(),
|
||||
stmt,
|
||||
)?;
|
||||
stmt = store_pattern(env, procs, layout_cache, guard_pattern, symbol, stmt)?;
|
||||
|
||||
stmt = Stmt::Let(symbol, load, destruct.layout.clone(), env.arena.alloc(stmt));
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue