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chore(tvix/eval): thread slot value through all compiler methods

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With this change any compilation of an expression is aware of its own
stack slot if it is leaving identifiers on the stack.

Change-Id: I0c9f148ae06b078a46b25180c4961686d5f2e166
Reviewed-on: https://cl.tvl.fyi/c/depot/+/6356
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
This commit is contained in:
Vincent Ambo 2022-08-29 21:51:08 +03:00 committed by tazjin
parent 50c33989dc
commit 6a42d9bddf
1 changed files with 58 additions and 54 deletions
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112
tvix/eval/src/compiler/mod.rs
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@ -110,20 +110,20 @@ impl Compiler {
match expr {
ast::Expr::Literal(literal) => self.compile_literal(literal),
ast::Expr::Path(path) => self.compile_path(path),
ast::Expr::Str(s) => self.compile_str(s),
ast::Expr::UnaryOp(op) => self.compile_unary_op(op),
ast::Expr::BinOp(op) => self.compile_binop(op),
ast::Expr::Str(s) => self.compile_str(slot, s),
ast::Expr::UnaryOp(op) => self.compile_unary_op(slot, op),
ast::Expr::BinOp(op) => self.compile_binop(slot, op),
ast::Expr::HasAttr(has_attr) => self.compile_has_attr(slot, has_attr),
ast::Expr::List(list) => self.compile_list(list),
ast::Expr::List(list) => self.compile_list(slot, list),
ast::Expr::AttrSet(attrs) => self.compile_attr_set(slot, attrs),
ast::Expr::Select(select) => self.compile_select(slot, select),
ast::Expr::Assert(assert) => self.compile_assert(assert),
ast::Expr::IfElse(if_else) => self.compile_if_else(if_else),
ast::Expr::LetIn(let_in) => self.compile_let_in(let_in),
ast::Expr::Assert(assert) => self.compile_assert(slot, assert),
ast::Expr::IfElse(if_else) => self.compile_if_else(slot, if_else),
ast::Expr::LetIn(let_in) => self.compile_let_in(slot, let_in),
ast::Expr::Ident(ident) => self.compile_ident(slot, ident),
ast::Expr::With(with) => self.compile_with(with),
ast::Expr::With(with) => self.compile_with(slot, with),
ast::Expr::Lambda(lambda) => self.compile_lambda(slot, lambda),
ast::Expr::Apply(apply) => self.compile_apply(apply),
ast::Expr::Apply(apply) => self.compile_apply(slot, apply),
// Parenthesized expressions are simply unwrapped, leaving
// their value on the stack.
@ -188,7 +188,7 @@ impl Compiler {
self.emit_constant(value);
}
fn compile_str(&mut self, node: ast::Str) {
fn compile_str(&mut self, slot: Option<LocalIdx>, node: ast::Str) {
let mut count = 0;
// The string parts are produced in literal order, however
@ -202,7 +202,7 @@ impl Compiler {
// Interpolated expressions are compiled as normal and
// dealt with by the VM before being assembled into
// the final string.
ast::InterpolPart::Interpolation(node) => self.compile(None, node.expr().unwrap()),
ast::InterpolPart::Interpolation(node) => self.compile(slot, node.expr().unwrap()),
ast::InterpolPart::Literal(lit) => {
self.emit_constant(Value::String(lit.into()));
@ -215,8 +215,8 @@ impl Compiler {
}
}
fn compile_unary_op(&mut self, op: ast::UnaryOp) {
self.compile(None, op.expr().unwrap());
fn compile_unary_op(&mut self, slot: Option<LocalIdx>, op: ast::UnaryOp) {
self.compile(slot, op.expr().unwrap());
let opcode = match op.operator().unwrap() {
ast::UnaryOpKind::Invert => OpCode::OpInvert,
@ -226,7 +226,7 @@ impl Compiler {
self.chunk().push_op(opcode);
}
fn compile_binop(&mut self, op: ast::BinOp) {
fn compile_binop(&mut self, slot: Option<LocalIdx>, op: ast::BinOp) {
use ast::BinOpKind;
// Short-circuiting and other strange operators, which are
@ -235,17 +235,17 @@ impl Compiler {
// used for standard binary operators).
match op.operator().unwrap() {
BinOpKind::And => return self.compile_and(op),
BinOpKind::Or => return self.compile_or(op),
BinOpKind::Implication => return self.compile_implication(op),
BinOpKind::And => return self.compile_and(slot, op),
BinOpKind::Or => return self.compile_or(slot, op),
BinOpKind::Implication => return self.compile_implication(slot, op),
_ => {}
};
// For all other operators, the two values need to be left on
// the stack in the correct order before pushing the
// instruction for the operation itself.
self.compile(None, op.lhs().unwrap());
self.compile(None, op.rhs().unwrap());
self.compile(slot, op.lhs().unwrap());
self.compile(slot, op.rhs().unwrap());
match op.operator().unwrap() {
BinOpKind::Add => self.chunk().push_op(OpCode::OpAdd),
@ -272,7 +272,7 @@ impl Compiler {
};
}
fn compile_and(&mut self, node: ast::BinOp) {
fn compile_and(&mut self, slot: Option<LocalIdx>, node: ast::BinOp) {
debug_assert!(
matches!(node.operator(), Some(ast::BinOpKind::And)),
"compile_and called with wrong operator kind: {:?}",
@ -280,7 +280,7 @@ impl Compiler {
);
// Leave left-hand side value on the stack.
self.compile(None, node.lhs().unwrap());
self.compile(slot, node.lhs().unwrap());
// If this value is false, jump over the right-hand side - the
// whole expression is false.
@ -290,13 +290,13 @@ impl Compiler {
// right-hand side on the stack. Its result is now the value
// of the whole expression.
self.chunk().push_op(OpCode::OpPop);
self.compile(None, node.rhs().unwrap());
self.compile(slot, node.rhs().unwrap());
self.patch_jump(end_idx);
self.chunk().push_op(OpCode::OpAssertBool);
}
fn compile_or(&mut self, node: ast::BinOp) {
fn compile_or(&mut self, slot: Option<LocalIdx>, node: ast::BinOp) {
debug_assert!(
matches!(node.operator(), Some(ast::BinOpKind::Or)),
"compile_or called with wrong operator kind: {:?}",
@ -304,18 +304,18 @@ impl Compiler {
);
// Leave left-hand side value on the stack
self.compile(None, node.lhs().unwrap());
self.compile(slot, node.lhs().unwrap());
// Opposite of above: If this value is **true**, we can
// short-circuit the right-hand side.
let end_idx = self.chunk().push_op(OpCode::OpJumpIfTrue(JumpOffset(0)));
self.chunk().push_op(OpCode::OpPop);
self.compile(None, node.rhs().unwrap());
self.compile(slot, node.rhs().unwrap());
self.patch_jump(end_idx);
self.chunk().push_op(OpCode::OpAssertBool);
}
fn compile_implication(&mut self, node: ast::BinOp) {
fn compile_implication(&mut self, slot: Option<LocalIdx>, node: ast::BinOp) {
debug_assert!(
matches!(node.operator(), Some(ast::BinOpKind::Implication)),
"compile_implication called with wrong operator kind: {:?}",
@ -323,20 +323,20 @@ impl Compiler {
);
// Leave left-hand side value on the stack and invert it.
self.compile(None, node.lhs().unwrap());
self.compile(slot, node.lhs().unwrap());
self.chunk().push_op(OpCode::OpInvert);
// Exactly as `||` (because `a -> b` = `!a || b`).
let end_idx = self.chunk().push_op(OpCode::OpJumpIfTrue(JumpOffset(0)));
self.chunk().push_op(OpCode::OpPop);
self.compile(None, node.rhs().unwrap());
self.compile(slot, node.rhs().unwrap());
self.patch_jump(end_idx);
self.chunk().push_op(OpCode::OpAssertBool);
}
fn compile_has_attr(&mut self, slot: Option<LocalIdx>, node: ast::HasAttr) {
// Put the attribute set on the stack.
self.compile(None, node.expr().unwrap());
self.compile(slot, node.expr().unwrap());
// Push all path fragments with an operation for fetching the
// next nested element, for all fragments except the last one.
@ -356,7 +356,7 @@ impl Compiler {
fn compile_attr(&mut self, slot: Option<LocalIdx>, node: ast::Attr) {
match node {
ast::Attr::Dynamic(dynamic) => self.compile(slot, dynamic.expr().unwrap()),
ast::Attr::Str(s) => self.compile_str(s),
ast::Attr::Str(s) => self.compile_str(slot, s),
ast::Attr::Ident(ident) => self.emit_literal_ident(&ident),
}
}
@ -367,12 +367,12 @@ impl Compiler {
//
// The VM, after evaluating the code for each element, simply
// constructs the list from the given number of elements.
fn compile_list(&mut self, node: ast::List) {
fn compile_list(&mut self, slot: Option<LocalIdx>, node: ast::List) {
let mut count = 0;
for item in node.items() {
count += 1;
self.compile(None, item);
self.compile(slot, item);
}
self.chunk().push_op(OpCode::OpList(Count(count)));
@ -490,7 +490,7 @@ impl Compiler {
}
// Push the set onto the stack
self.compile(None, set);
self.compile(slot, set);
// Compile each key fragment and emit access instructions.
//
@ -538,7 +538,7 @@ impl Compiler {
path: ast::Attrpath,
default: ast::Expr,
) {
self.compile(None, set);
self.compile(slot, set);
let mut jumps = vec![];
for fragment in path.attrs() {
@ -562,15 +562,15 @@ impl Compiler {
self.patch_jump(final_jump);
}
fn compile_assert(&mut self, node: ast::Assert) {
fn compile_assert(&mut self, slot: Option<LocalIdx>, node: ast::Assert) {
// Compile the assertion condition to leave its value on the stack.
self.compile(None, node.condition().unwrap());
self.compile(slot, node.condition().unwrap());
self.chunk().push_op(OpCode::OpAssert);
// The runtime will abort evaluation at this point if the
// assertion failed, if not the body simply continues on like
// normal.
self.compile(None, node.body().unwrap());
self.compile(slot, node.body().unwrap());
}
// Compile conditional expressions using jumping instructions in the VM.
@ -583,25 +583,29 @@ impl Compiler {
// Jump over else body ││ 4 [ else body ]←┼─┘
// if condition is true.└┼─5─→ ... │
// └────────────────────┘
fn compile_if_else(&mut self, node: ast::IfElse) {
self.compile(None, node.condition().unwrap());
fn compile_if_else(&mut self, slot: Option<LocalIdx>, node: ast::IfElse) {
self.compile(slot, node.condition().unwrap());
let then_idx = self.chunk().push_op(OpCode::OpJumpIfFalse(JumpOffset(0)));
self.chunk().push_op(OpCode::OpPop); // discard condition value
self.compile(None, node.body().unwrap());
self.compile(slot, node.body().unwrap());
let else_idx = self.chunk().push_op(OpCode::OpJump(JumpOffset(0)));
self.patch_jump(then_idx); // patch jump *to* else_body
self.chunk().push_op(OpCode::OpPop); // discard condition value
self.compile(None, node.else_body().unwrap());
self.compile(slot, node.else_body().unwrap());
self.patch_jump(else_idx); // patch jump *over* else body
}
// Compile an `inherit` node of a `let`-expression.
fn compile_let_inherit<I: Iterator<Item = ast::Inherit>>(&mut self, inherits: I) {
fn compile_let_inherit<I: Iterator<Item = ast::Inherit>>(
&mut self,
slot: Option<LocalIdx>,
inherits: I,
) {
for inherit in inherits {
match inherit.from() {
// Within a `let` binding, inheriting from the outer
@ -626,7 +630,7 @@ impl Compiler {
continue;
}
self.compile_ident(None, ident.clone());
self.compile_ident(slot, ident.clone());
let idx = self.declare_local(
ident.syntax().clone(),
ident.ident_token().unwrap().text(),
@ -637,7 +641,7 @@ impl Compiler {
Some(from) => {
for ident in inherit.idents() {
self.compile(None, from.expr().unwrap());
self.compile(slot, from.expr().unwrap());
self.emit_literal_ident(&ident);
self.chunk().push_op(OpCode::OpAttrsSelect);
let idx = self.declare_local(
@ -656,10 +660,10 @@ impl Compiler {
// Unless in a non-standard scope, the encountered values are
// simply pushed on the stack and their indices noted in the
// entries vector.
fn compile_let_in(&mut self, node: ast::LetIn) {
fn compile_let_in(&mut self, slot: Option<LocalIdx>, node: ast::LetIn) {
self.begin_scope();
self.compile_let_inherit(node.inherits());
self.compile_let_inherit(slot, node.inherits());
// First pass to ensure that all identifiers are known;
// required for resolving recursion.
@ -704,7 +708,7 @@ impl Compiler {
}
// Deal with the body, then clean up the locals afterwards.
self.compile(None, node.body().unwrap());
self.compile(slot, node.body().unwrap());
self.end_scope();
}
@ -775,12 +779,12 @@ impl Compiler {
// Compile `with` expressions by emitting instructions that
// pop/remove the indices of attribute sets that are implicitly in
// scope through `with` on the "with-stack".
fn compile_with(&mut self, node: ast::With) {
fn compile_with(&mut self, slot: Option<LocalIdx>, node: ast::With) {
self.begin_scope();
// TODO: Detect if the namespace is just an identifier, and
// resolve that directly (thus avoiding duplication on the
// stack).
self.compile(None, node.namespace().unwrap());
self.compile(slot, node.namespace().unwrap());
let local_idx = self.scope_mut().declare_phantom();
let with_idx = self.scope().stack_index(local_idx);
@ -788,7 +792,7 @@ impl Compiler {
self.chunk().push_op(OpCode::OpPushWith(with_idx));
self.compile(None, node.body().unwrap());
self.compile(slot, node.body().unwrap());
self.chunk().push_op(OpCode::OpPopWith);
self.scope_mut().pop_with();
@ -818,7 +822,7 @@ impl Compiler {
}
}
self.compile(None, node.body().unwrap());
self.compile(slot, node.body().unwrap());
self.end_scope();
// TODO: determine and insert enclosing name, if available.
@ -851,13 +855,13 @@ impl Compiler {
self.emit_upvalue_data(slot, compiled.scope.upvalues);
}
fn compile_apply(&mut self, node: ast::Apply) {
fn compile_apply(&mut self, slot: Option<LocalIdx>, node: ast::Apply) {
// To call a function, we leave its arguments on the stack,
// followed by the function expression itself, and then emit a
// call instruction. This way, the stack is perfectly laid out
// to enter the function call straight away.
self.compile(None, node.argument().unwrap());
self.compile(None, node.lambda().unwrap());
self.compile(slot, node.argument().unwrap());
self.compile(slot, node.lambda().unwrap());
self.chunk().push_op(OpCode::OpCall);
}