Files
wasmtime/src/libreader/sourcemap.rs
Jakob Stoklund Olesen dd8e7df8ba Add an internal MutableSourceMap trait.
Use the SourceMap for mapping during parsing too.
2016-09-19 11:13:11 -07:00

224 lines
7.8 KiB
Rust

//! Source map for translating source entity names to parsed entities.
//!
//! When the parser reads in a source file, entities like instructions, EBBs, and values get new
//! entity numbers. The parser maintains a mapping from the entity names in the source to the final
//! entity references.
//!
//! The `SourceMap` struct defined in this module makes the same mapping available to parser
//! clients.
use std::collections::HashMap;
use cretonne::ir::{StackSlot, JumpTable, Ebb, Value};
use cretonne::ir::entities::AnyEntity;
use error::{Result, Location};
/// Mapping from source entity names to entity references that are valid in the parsed function.
#[derive(Debug)]
pub struct SourceMap {
values: HashMap<Value, Value>, // vNN, vxNN
ebbs: HashMap<Ebb, Ebb>, // ebbNN
stack_slots: HashMap<u32, StackSlot>, // ssNN
jump_tables: HashMap<u32, JumpTable>, // jtNN
}
/// Read-only interface which is exposed outside the parser crate.
impl SourceMap {
/// Look up a value entity by its source number.
pub fn get_value(&self, src: Value) -> Option<Value> {
self.values.get(&src).cloned()
}
/// Look up a EBB entity by its source number.
pub fn get_ebb(&self, src: Ebb) -> Option<Ebb> {
self.ebbs.get(&src).cloned()
}
/// Look up a stack slot entity by its source number.
pub fn get_ss(&self, src_num: u32) -> Option<StackSlot> {
self.stack_slots.get(&src_num).cloned()
}
/// Look up a jump table entity by its source number.
pub fn get_jt(&self, src_num: u32) -> Option<JumpTable> {
self.jump_tables.get(&src_num).cloned()
}
/// Look up an entity by source name.
/// Returns the entity reference corresponding to `name`, if it exists.
pub fn lookup_str(&self, name: &str) -> Option<AnyEntity> {
split_entity_name(name).and_then(|(ent, num)| {
match ent {
"v" => {
Value::direct_with_number(num)
.and_then(|v| self.get_value(v))
.map(AnyEntity::Value)
}
"vx" => {
Value::table_with_number(num)
.and_then(|v| self.get_value(v))
.map(AnyEntity::Value)
}
"ebb" => Ebb::with_number(num).and_then(|e| self.get_ebb(e)).map(AnyEntity::Ebb),
"ss" => self.get_ss(num).map(AnyEntity::StackSlot),
"jt" => self.get_jt(num).map(AnyEntity::JumpTable),
_ => None,
}
})
}
/// Rewrite an Ebb reference.
pub fn rewrite_ebb(&self, ebb: &mut Ebb, loc: &Location) -> Result<()> {
match self.get_ebb(*ebb) {
Some(new) => {
*ebb = new;
Ok(())
}
None => err!(loc, "undefined reference: {}", ebb),
}
}
/// Rewrite a value reference.
pub fn rewrite_value(&self, val: &mut Value, loc: &Location) -> Result<()> {
match self.get_value(*val) {
Some(new) => {
*val = new;
Ok(())
}
None => err!(loc, "undefined reference: {}", val),
}
}
/// Rewrite a slice of value references.
pub fn rewrite_values(&self, vals: &mut [Value], loc: &Location) -> Result<()> {
for val in vals {
try!(self.rewrite_value(val, loc));
}
Ok(())
}
}
/// Get the number of decimal digits at the end of `s`.
fn trailing_digits(s: &str) -> usize {
// It's faster to iterate backwards over bytes, and we're only counting ASCII digits.
s.as_bytes().iter().rev().cloned().take_while(|&b| b'0' <= b && b <= b'9').count()
}
/// Pre-parse a supposed entity name by splitting it into two parts: A head of lowercase ASCII
/// letters and numeric tail.
fn split_entity_name(name: &str) -> Option<(&str, u32)> {
let (head, tail) = name.split_at(name.len() - trailing_digits(name));
if tail.len() > 1 && tail.starts_with('0') {
None
} else {
tail.parse().ok().map(|n| (head, n))
}
}
/// Interface for mutating a source map.
///
/// This interface is provided for the parser itself, it is not made available outside the crate.
pub trait MutableSourceMap {
fn new() -> Self;
/// Define a value mapping from the source name `src` to the final `entity`.
fn def_value(&mut self, src: Value, entity: Value, loc: &Location) -> Result<()>;
fn def_ebb(&mut self, src: Ebb, entity: Ebb, loc: &Location) -> Result<()>;
fn def_ss(&mut self, src_num: u32, entity: StackSlot, loc: &Location) -> Result<()>;
fn def_jt(&mut self, src_num: u32, entity: JumpTable, loc: &Location) -> Result<()>;
}
impl MutableSourceMap for SourceMap {
fn new() -> SourceMap {
SourceMap {
values: HashMap::new(),
ebbs: HashMap::new(),
stack_slots: HashMap::new(),
jump_tables: HashMap::new(),
}
}
fn def_value(&mut self, src: Value, entity: Value, loc: &Location) -> Result<()> {
if self.values.insert(src, entity).is_some() {
err!(loc, "duplicate value: {}", src)
} else {
Ok(())
}
}
fn def_ebb(&mut self, src: Ebb, entity: Ebb, loc: &Location) -> Result<()> {
if self.ebbs.insert(src, entity).is_some() {
err!(loc, "duplicate EBB: {}", src)
} else {
Ok(())
}
}
fn def_ss(&mut self, src_num: u32, entity: StackSlot, loc: &Location) -> Result<()> {
if self.stack_slots.insert(src_num, entity).is_some() {
err!(loc, "duplicate stack slot: ss{}", src_num)
} else {
Ok(())
}
}
fn def_jt(&mut self, src_num: u32, entity: JumpTable, loc: &Location) -> Result<()> {
if self.jump_tables.insert(src_num, entity).is_some() {
err!(loc, "duplicate jump table: jt{}", src_num)
} else {
Ok(())
}
}
}
#[cfg(test)]
mod tests {
use super::{trailing_digits, split_entity_name};
use parse_test;
#[test]
fn digits() {
assert_eq!(trailing_digits(""), 0);
assert_eq!(trailing_digits("x"), 0);
assert_eq!(trailing_digits("0x"), 0);
assert_eq!(trailing_digits("x1"), 1);
assert_eq!(trailing_digits("1x1"), 1);
assert_eq!(trailing_digits("1x01"), 2);
}
#[test]
fn entity_name() {
assert_eq!(split_entity_name(""), None);
assert_eq!(split_entity_name("x"), None);
assert_eq!(split_entity_name("x+"), None);
assert_eq!(split_entity_name("x+1"), Some(("x+", 1)));
assert_eq!(split_entity_name("x-1"), Some(("x-", 1)));
assert_eq!(split_entity_name("1"), Some(("", 1)));
assert_eq!(split_entity_name("x1"), Some(("x", 1)));
assert_eq!(split_entity_name("xy0"), Some(("xy", 0)));
// Reject this non-canonical form.
assert_eq!(split_entity_name("inst01"), None);
}
#[test]
fn details() {
let tf = parse_test("function detail() {
ss10 = stack_slot 13
jt10 = jump_table ebb0
ebb0(v4: i32, vx7: i32):
v10 = iadd v4, vx7
}")
.unwrap();
let map = &tf.functions[0].1.map;
assert_eq!(map.lookup_str("v0"), None);
assert_eq!(map.lookup_str("ss1"), None);
assert_eq!(map.lookup_str("ss10").unwrap().to_string(), "ss0");
assert_eq!(map.lookup_str("jt10").unwrap().to_string(), "jt0");
assert_eq!(map.lookup_str("ebb0").unwrap().to_string(), "ebb0");
assert_eq!(map.lookup_str("v4").unwrap().to_string(), "vx0");
assert_eq!(map.lookup_str("vx7").unwrap().to_string(), "vx1");
assert_eq!(map.lookup_str("v10").unwrap().to_string(), "v0");
}
}