employer
/
tame
1
0
Fork 0
Code Packages Releases Activity
tame/tamer/src/asg/graph.rs

825 lines
25 KiB
Rust
Raw Blame History

// Graph abstraction
//
// Copyright (C) 2014-2022 Ryan Specialty Group, LLC.
//
// This file is part of TAME.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//! Abstract graph as the basis for concrete ASGs.
use super::{
AsgError, FragmentText, Ident, IdentKind, Object, Source, TransitionResult,
};
use crate::global;
use crate::parse::util::SPair;
use crate::parse::Token;
use crate::sym::SymbolId;
use petgraph::graph::{DiGraph, Graph, NodeIndex};
use std::fmt::Debug;
use std::result::Result;
/// Datatype representing node and edge indexes.
pub trait IndexType = petgraph::graph::IndexType;
/// A [`Result`] with a hard-coded [`AsgError`] error type.
///
/// This is the result of every [`Asg`] operation that could potentially
/// fail in error.
pub type AsgResult<T> = Result<T, AsgError>;
/// There are currently no data stored on edges ("edge weights").
pub type AsgEdge = ();
/// Each node of the graph represents an object.
///
/// Enclosed in an [`Option`] to permit moving owned values out of the
/// graph.
pub type Node = Option<Object>;
/// Index size for Graph nodes and edges.
type Ix = global::ProgSymSize;
/// An abstract semantic graph (ASG) of [objects][super::object].
///
/// This implementation is currently based on [`petgraph`].
///
/// Identifiers are cached by name for `O(1)` lookup.
/// Since [`SymbolId`][crate::sym::SymbolId] is used for this purpose,
/// the index may contain more entries than nodes and may contain gaps.
///
/// This IR focuses on the definition and manipulation of objects and their
/// dependencies.
/// See [`Ident`]for a summary of valid identifier object state
/// transitions.
///
/// Objects are never deleted from the graph,
/// so [`ObjectRef`]s will remain valid for the lifetime of the ASG.
///
/// For more information,
/// see the [module-level documentation][self].
#[derive(Debug)]
pub struct Asg {
// TODO: private; see `ld::xmle::lower`.
/// Directed graph on which objects are stored.
pub graph: DiGraph<Node, AsgEdge, Ix>,
/// Map of [`SymbolId`][crate::sym::SymbolId] to node indexes.
///
/// This allows for `O(1)` lookup of identifiers in the graph.
/// Note that,
/// while we store [`NodeIndex`] internally,
/// the public API encapsulates it within an [`ObjectRef`].
index: Vec<NodeIndex<Ix>>,
/// Empty node indicating that no object exists for a given index.
empty_node: NodeIndex<Ix>,
/// The root node used for reachability analysis and topological
/// sorting.
root_node: NodeIndex<Ix>,
}
impl Default for Asg {
fn default() -> Self {
Self::new()
}
}
impl Asg {
/// Create a new ASG.
///
/// See also [`with_capacity`](Asg::with_capacity).
pub fn new() -> Self {
// TODO: Determine a proper initial capacity.
Self::with_capacity(0, 0)
}
/// Create an ASG with the provided initial capacity.
///
/// The value for `objects` will be used as the capacity for the nodes
/// in the graph,
/// as well as the initial index capacity.
/// The value for `edges` may be more difficult to consider,
/// since edges are used to represent various relationships between
/// different types of objects,
/// but it's safe to say that each object will have at least one
/// edge to another object.
pub fn with_capacity(objects: usize, edges: usize) -> Self {
let mut graph = Graph::with_capacity(objects, edges);
let mut index = Vec::with_capacity(objects);
// Exhaust the first index to be used as a placeholder.
let empty_node = graph.add_node(None);
index.push(empty_node);
// Automatically add the root which will be used to determine what
// identifiers ought to be retained by the final program.
// This is not indexed and is not accessable by name.
let root_node = graph.add_node(Some(Object::Root));
Self {
graph,
index,
empty_node,
root_node,
}
}
/// Get the underlying Graph
pub fn into_inner(self) -> DiGraph<Node, AsgEdge, Ix> {
self.graph
}
/// Index the provided symbol `name` as representing the identifier `node`.
///
/// This index permits `O(1)` identifier lookups.
///
/// After an identifier is indexed it is not expected to be reassigned
/// to another node.
/// Debug builds contain an assertion that will panic in this instance.
///
/// Panics
/// ======
/// Will panic if unable to allocate more space for the index.
fn index_identifier(&mut self, name: SymbolId, node: NodeIndex<Ix>) {
let i = name.as_usize();
if i >= self.index.len() {
// If this is ever a problem we can fall back to usize max and
// re-compare before panicing
let new_size = (i + 1)
.checked_next_power_of_two()
.expect("internal error: cannot allocate space for ASG index");
self.index.resize(new_size, self.empty_node);
}
// We should never overwrite indexes
debug_assert!(self.index[i] == self.empty_node);
self.index[i] = node;
}
/// Lookup `ident` or add a missing identifier to the graph and return a
/// reference to it.
///
/// The provided span is necessary to seed the missing identifier with
/// some sort of context to aid in debugging why a missing identifier
/// was introduced to the graph.
///
/// See [`Ident::declare`] for more information.
pub(super) fn lookup_or_missing(&mut self, ident: SPair) -> ObjectRef {
let sym = ident.symbol();
self.lookup(sym).unwrap_or_else(|| {
let index = self.graph.add_node(Some(Ident::declare(ident).into()));
self.index_identifier(sym, index);
ObjectRef::new(index)
})
}
/// Perform a state transition on an identifier by name.
///
/// Look up `ident` or add a missing identifier if it does not yet exist
/// (see [`Self::lookup_or_missing`]).
/// Then invoke `f` with the located identifier and replace the
/// identifier on the graph with the result.
///
/// This will safely restore graph state to the original identifier
/// value on transition failure.
fn with_ident_lookup<F>(
&mut self,
name: SPair,
f: F,
) -> AsgResult<ObjectRef>
where
F: FnOnce(Ident) -> TransitionResult<Ident>,
{
let identi = self.lookup_or_missing(name);
self.with_ident(identi, f)
}
/// Perform a state transition on an identifier by [`ObjectRef`].
///
/// Invoke `f` with the located identifier and replace the identifier on
/// the graph with the result.
///
/// This will safely restore graph state to the original identifier
/// value on transition failure.
fn with_ident<F>(&mut self, identi: ObjectRef, f: F) -> AsgResult<ObjectRef>
where
F: FnOnce(Ident) -> TransitionResult<Ident>,
{
let node = self.graph.node_weight_mut(identi.into()).unwrap();
let obj = node
.take()
.expect("internal error: missing object")
.unwrap_ident();
f(obj)
.and_then(|obj| {
node.replace(obj.into());
Ok(identi)
})
.or_else(|(orig, err)| {
node.replace(orig.into());
Err(err.into())
})
}
// TODO: This is transitional;
// remove once [`crate::xmlo::asg_builder`] is removed.
pub fn root(&self) -> NodeIndex<Ix> {
self.root_node
}
/// Add an object as a root.
///
/// Roots are always included during a topological sort and any
/// reachability analysis.
///
/// Ideally,
/// roots would be minimal and dependencies properly organized such
/// that objects will be included if they are a transitive dependency
/// of some included subsystem.
///
/// See also [`IdentKind::is_auto_root`].
pub fn add_root(&mut self, identi: ObjectRef) {
self.graph
.add_edge(self.root_node, identi.into(), Default::default());
}
/// Whether an object is rooted.
///
/// See [`Asg::add_root`] for more information about roots.
#[cfg(test)]
pub(super) fn is_rooted(&self, identi: ObjectRef) -> bool {
self.graph.contains_edge(self.root_node, identi.into())
}
/// Declare a concrete identifier.
///
/// An identifier declaration is similar to a declaration in a header
/// file in a language like C,
/// describing the structure of the identifier.
/// Once declared,
/// this information cannot be changed.
///
/// Identifiers are uniquely identified by a [`SymbolId`] `name`.
/// If an identifier of the same `name` already exists,
/// then the provided declaration is compared against the existing
/// declaration---should
/// they be incompatible,
/// then the operation will fail;
/// otherwise,
/// the existing identifier will be returned.
///
/// If a concrete identifier has already been declared (see
/// [`Asg::declare`]),
/// then extern declarations will be compared and,
/// if compatible,
/// the identifier will be immediately _resolved_ and the object
/// on the graph will not be altered.
/// Resolution will otherwise fail in error.
///
/// For more information on state transitions that can occur when
/// redeclaring an identifier that already exists,
/// see [`Ident::resolve`].
///
/// A successful declaration will add an identifier to the graph
/// and return an [`ObjectRef`] reference.
pub fn declare(
&mut self,
name: SPair,
kind: IdentKind,
src: Source,
) -> AsgResult<ObjectRef> {
let is_auto_root = kind.is_auto_root();
self.with_ident_lookup(name, |obj| obj.resolve(name.span(), kind, src))
.and_then(|node| {
is_auto_root.then(|| self.add_root(node));
Ok(node)
})
}
/// Declare an abstract identifier.
///
/// An _extern_ declaration declares an identifier the same as
/// [`Asg::declare`],
/// but omits source information.
/// Externs are identifiers that are expected to be defined somewhere
/// else ("externally"),
/// and are resolved at [link-time][crate::ld].
///
/// If a concrete identifier has already been declared (see
/// [`Asg::declare`]),
/// then the declarations will be compared and,
/// if compatible,
/// the identifier will be immediately _resolved_ and the object
/// on the graph will not be altered.
/// Resolution will otherwise fail in error.
///
/// See [`Ident::extern_`] and
/// [`Ident::resolve`] for more information on
/// compatibility related to extern resolution.
pub fn declare_extern(
&mut self,
name: SPair,
kind: IdentKind,
src: Source,
) -> AsgResult<ObjectRef> {
self.with_ident_lookup(name, |obj| obj.extern_(name.span(), kind, src))
}
/// Set the fragment associated with a concrete identifier.
///
/// Fragments are intended for use by the [linker][crate::ld].
/// For more information,
/// see [`Ident::set_fragment`].
pub fn set_fragment(
&mut self,
name: SPair,
text: FragmentText,
) -> AsgResult<ObjectRef> {
self.with_ident_lookup(name, |obj| obj.set_fragment(text))
}
/// Retrieve an object from the graph by [`ObjectRef`].
///
/// Since an [`ObjectRef`] should only be produced by an [`Asg`],
/// and since objects are never deleted from the graph,
/// this should never fail so long as references are not shared
/// between multiple graphs.
/// It is nevertheless wrapped in an [`Option`] just in case.
#[inline]
pub fn get<I: Into<ObjectRef>>(&self, index: I) -> Option<&Object> {
self.graph.node_weight(index.into().into()).map(|node| {
node.as_ref()
.expect("internal error: Asg::get missing Node data")
})
}
/// Retrieve an identifier from the graph by [`ObjectRef`].
///
/// If the object exists but is not an identifier,
/// [`None`] will be returned.
#[inline]
pub fn get_ident<I: Into<ObjectRef>>(&self, index: I) -> Option<&Ident> {
self.get(index).and_then(Object::as_ident_ref)
}
/// Attempt to retrieve an identifier from the graph by name.
///
/// Since only identifiers carry a name,
/// this method cannot be used to retrieve all possible objects on the
/// graph---for
/// that, see [`Asg::get`].
#[inline]
pub fn lookup(&self, name: SymbolId) -> Option<ObjectRef> {
let i = name.as_usize();
self.index
.get(i)
.filter(|ni| ni.index() > 0)
.map(|ni| ObjectRef::new(*ni))
}
/// Declare that `dep` is a dependency of `ident`.
///
/// An object must be declared as a dependency if its value must be
/// computed before computing the value of `ident`.
/// The [linker][crate::ld] will ensure this ordering.
///
/// See [`add_dep_lookup`][Asg::add_dep_lookup] if identifiers have to
/// be looked up by [`SymbolId`] or if they may not yet have been
/// declared.
pub fn add_dep(&mut self, identi: ObjectRef, depi: ObjectRef) {
self.graph
.update_edge(identi.into(), depi.into(), Default::default());
}
/// Check whether `dep` is a dependency of `ident`.
#[inline]
pub fn has_dep(&self, ident: ObjectRef, dep: ObjectRef) -> bool {
self.graph.contains_edge(ident.into(), dep.into())
}
/// Declare that `dep` is a dependency of `ident`,
/// regardless of whether they are known.
///
/// In contrast to [`add_dep`][Asg::add_dep],
/// this method will add the dependency even if one or both of `ident`
/// or `dep` have not yet been declared.
/// In such a case,
/// a missing identifier will be added as a placeholder,
/// allowing the ASG to be built with partial information as
/// identifiers continue to be discovered.
/// See [`Ident::declare`] for more information.
///
/// References to both identifiers are returned in argument order.
pub fn add_dep_lookup(
&mut self,
ident: SPair,
dep: SPair,
) -> (ObjectRef, ObjectRef) {
let identi = self.lookup_or_missing(ident);
let depi = self.lookup_or_missing(dep);
self.graph
.update_edge(identi.into(), depi.into(), Default::default());
(identi, depi)
}
}
/// Reference to an [object][super::object] stored within the [`Asg`].
///
/// Ident references are integer offsets,
/// not pointers.
/// See the [module-level documentation][self] for more information.
#[derive(Debug, Copy, Clone, Default, PartialEq, Eq)]
pub struct ObjectRef(NodeIndex);
impl ObjectRef {
pub fn new(index: NodeIndex) -> Self {
Self(index)
}
}
impl From<NodeIndex> for ObjectRef {
fn from(index: NodeIndex) -> Self {
Self(index)
}
}
impl From<ObjectRef> for NodeIndex {
fn from(objref: ObjectRef) -> Self {
objref.0
}
}
#[cfg(test)]
mod test {
use super::super::error::AsgError;
use super::*;
use crate::{num::Dim, span::dummy::*, sym::GlobalSymbolIntern};
use std::assert_matches::assert_matches;
type Sut = Asg;
#[test]
fn create_with_capacity() {
let node_capacity = 100;
let edge_capacity = 300;
let sut = Sut::with_capacity(node_capacity, edge_capacity);
let (nc, ec) = sut.graph.capacity();
assert!(nc >= node_capacity);
assert!(ec >= edge_capacity);
assert!(sut.index.capacity() >= node_capacity);
}
#[test]
fn declare_new_unique_idents() -> AsgResult<()> {
let mut sut = Sut::new();
// NB: The index ordering is important! We first use a larger
// index to create a gap, and then use an index within that gap
// to ensure that it's not considered an already-defined
// identifier.
let syma = "syma".into();
let symb = "symab".into();
let nodea = sut.declare(
SPair(syma, S1),
IdentKind::Meta,
Source {
desc: Some("a".into()),
..Default::default()
},
)?;
let nodeb = sut.declare(
SPair(symb, S2),
IdentKind::Worksheet,
Source {
desc: Some("b".into()),
..Default::default()
},
)?;
assert_ne!(nodea, nodeb);
let givena = sut.get_ident(nodea).unwrap();
assert_eq!(SPair(syma, S1), givena.name());
assert_eq!(Some(&IdentKind::Meta), givena.kind());
assert_eq!(
Some(&Source {
desc: Some("a".into()),
..Default::default()
},),
givena.src()
);
let givenb = sut.get_ident(nodeb).unwrap();
assert_eq!(SPair(symb, S2), givenb.name());
assert_eq!(Some(&IdentKind::Worksheet), givenb.kind());
assert_eq!(
Some(&Source {
desc: Some("b".into()),
..Default::default()
}),
givenb.src()
);
Ok(())
}
#[test]
fn declare_kind_auto_root() -> AsgResult<()> {
let mut sut = Sut::new();
let auto_kind = IdentKind::Worksheet;
// Sanity check, in case this changes.
assert!(auto_kind.is_auto_root());
let auto_root_node = sut.declare(
SPair("auto_root".into(), S1),
auto_kind,
Default::default(),
)?;
// Should have been automatically added as a root.
assert!(sut
.graph
.contains_edge(sut.root_node, auto_root_node.into()));
let no_auto_kind = IdentKind::Tpl;
assert!(!no_auto_kind.is_auto_root());
let no_auto_root_node = sut.declare(
SPair("no_auto_root".into(), S2),
no_auto_kind,
Default::default(),
)?;
// Non-auto-roots should _not_ be added as roots automatically.
assert!(!sut
.graph
.contains_edge(sut.root_node, no_auto_root_node.into()));
Ok(())
}
#[test]
fn lookup_by_symbol() -> AsgResult<()> {
let mut sut = Sut::new();
let sym = "lookup".into();
let node = sut.declare(
SPair(sym, S1),
IdentKind::Meta,
Source {
generated: true,
..Default::default()
},
)?;
assert_eq!(Some(node), sut.lookup(sym));
Ok(())
}
#[test]
fn declare_fails_if_transition_fails() -> AsgResult<()> {
let mut sut = Sut::new();
let sym = "symdup".into();
let src = Source {
desc: Some("orig".into()),
..Default::default()
};
// Set up an object to fail redeclaration.
let node = sut.declare(SPair(sym, S1), IdentKind::Meta, src.clone())?;
let result =
sut.declare(SPair(sym, S2), IdentKind::Meta, Source::default());
assert_matches!(result, Err(AsgError::IdentTransition(..)));
// The node should have been restored.
assert_eq!(Some(&src), sut.get_ident(node).unwrap().src());
Ok(())
}
#[test]
fn declare_extern_returns_existing() -> AsgResult<()> {
let mut sut = Sut::new();
let sym = "symext".into();
let src = Source::default();
let kind = IdentKind::Class(Dim::Matrix);
let node =
sut.declare_extern(SPair(sym, S1), kind.clone(), src.clone())?;
let resrc = Source {
desc: Some("redeclare".into()),
..Default::default()
};
let redeclare =
sut.declare_extern(SPair(sym, S2), kind.clone(), resrc.clone())?;
assert_eq!(node, redeclare);
Ok(())
}
// Builds upon declare_returns_existing.
#[test]
fn declare_extern_fails_if_transition_fails() -> AsgResult<()> {
let mut sut = Sut::new();
let sym = "symdup".into();
let src = Source {
desc: Some("orig".into()),
..Default::default()
};
let node = sut.declare(SPair(sym, S1), IdentKind::Meta, src.clone())?;
// Changes kind, which is invalid.
let result = sut.declare_extern(
SPair(sym, S2),
IdentKind::Worksheet,
Source::default(),
);
assert_matches!(result, Err(AsgError::IdentTransition(..)));
// The node should have been restored.
assert_eq!(Some(&src), sut.get_ident(node).unwrap().src());
Ok(())
}
#[test]
fn add_fragment_to_ident() -> AsgResult<()> {
let mut sut = Sut::new();
let sym = "tofrag".into();
let src = Source {
generated: true,
..Default::default()
};
let node = sut.declare(SPair(sym, S1), IdentKind::Meta, src.clone())?;
let fragment = "a fragment".intern();
let node_with_frag = sut.set_fragment(SPair(sym, S2), fragment)?;
// Attaching a fragment should _replace_ the node, not create a
// new one
assert_eq!(
node, node_with_frag,
"fragment node does not match original node"
);
let obj = sut.get_ident(node).unwrap();
assert_eq!(SPair(sym, S1), obj.name());
assert_eq!(Some(&IdentKind::Meta), obj.kind());
assert_eq!(Some(&src), obj.src());
assert_eq!(Some(fragment), obj.fragment());
Ok(())
}
#[test]
fn add_fragment_to_ident_fails_if_transition_fails() -> AsgResult<()> {
let mut sut = Sut::new();
let sym = "failfrag".into();
let src = Source {
generated: true,
..Default::default()
};
// The failure will come from terr below, not this.
let node = sut.declare(SPair(sym, S1), IdentKind::Meta, src.clone())?;
// The first set will succeed.
sut.set_fragment(SPair(sym, S2), "".into())?;
// This will fail.
let result = sut.set_fragment(SPair(sym, S3), "".into());
// The node should have been restored.
let obj = sut.get_ident(node).unwrap();
assert_eq!(SPair(sym, S1), obj.name());
assert_matches!(result, Err(AsgError::IdentTransition(..)));
Ok(())
}
#[test]
fn add_ident_dep_to_ident() -> AsgResult<()> {
let mut sut = Sut::new();
let sym = "sym".into();
let dep = "dep".into();
let symnode =
sut.declare(SPair(sym, S1), IdentKind::Meta, Source::default())?;
let depnode =
sut.declare(SPair(dep, S2), IdentKind::Meta, Source::default())?;
sut.add_dep(symnode, depnode);
assert!(sut.has_dep(symnode, depnode));
// sanity check if we re-add a dep
sut.add_dep(symnode, depnode);
assert!(sut.has_dep(symnode, depnode));
Ok(())
}
// same as above test
#[test]
fn add_dep_lookup_existing() -> AsgResult<()> {
let mut sut = Sut::new();
let sym = SPair("sym".into(), S1);
let dep = SPair("dep".into(), S2);
let _ = sut.declare(sym, IdentKind::Meta, Source::default())?;
let _ = sut.declare(dep, IdentKind::Meta, Source::default())?;
let (symnode, depnode) = sut.add_dep_lookup(sym, dep);
assert!(sut.has_dep(symnode, depnode));
Ok(())
}
#[test]
fn add_dep_lookup_missing() -> AsgResult<()> {
let mut sut = Sut::new();
let sym = SPair("sym".into(), S1);
let dep = SPair("dep".into(), S2);
// both of these are missing
let (symnode, depnode) = sut.add_dep_lookup(sym, dep);
assert!(sut.has_dep(symnode, depnode));
assert_eq!(sym, sut.get_ident(symnode).unwrap().name());
assert_eq!(dep, sut.get_ident(depnode).unwrap().name());
Ok(())
}
#[test]
fn declare_return_missing_symbol() -> AsgResult<()> {
let mut sut = Sut::new();
let sym = SPair("sym".into(), S1);
let dep = SPair("dep".into(), S2);
// both of these are missing, see add_dep_lookup_missing
let (symnode, _) = sut.add_dep_lookup(sym, dep);
let src = Source {
desc: Some("redeclare missing".into()),
..Default::default()
};
// Check with a declared value
let declared = sut.declare(sym, IdentKind::Meta, src.clone())?;
assert_eq!(symnode, declared);
let obj = sut.get_ident(declared).unwrap();
assert_eq!(sym, obj.name());
assert_eq!(Some(&IdentKind::Meta), obj.kind());
assert_eq!(Some(&src), obj.src());
Ok(())
}
}
View Git Blame Copy Permalink