Move library crates under 'lib/'.
Give these crates each a more standard directory layout with sources in a 'src' sub-sirectory and Cargo.toml in the top lib/foo directory. Add license and description fields to each. The build script for the cretonne crate now lives in 'lib/cretonne/build.rs' separating it from the normal library sources under 'lib/cretonne/src'.
This commit is contained in:
Jakob Stoklund Olesen
489
lib/reader/src/lexer.rs
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489
lib/reader/src/lexer.rs
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@@ -0,0 +1,489 @@
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// ====--------------------------------------------------------------------------------------====//
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//
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// Lexical analysis for .cton files.
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//
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// ====--------------------------------------------------------------------------------------====//
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use std::str::CharIndices;
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use std::u16;
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use cretonne::ir::types;
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use cretonne::ir::{Value, Ebb};
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use error::Location;
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/// A Token returned from the `Lexer`.
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///
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/// Some variants may contains references to the original source text, so the `Token` has the same
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/// lifetime as the source.
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#[derive(Debug, PartialEq, Eq, Clone, Copy)]
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pub enum Token<'a> {
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Comment(&'a str),
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LPar, // '('
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RPar, // ')'
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LBrace, // '{'
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RBrace, // '}'
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Comma, // ','
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Dot, // '.'
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Colon, // ':'
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Equal, // '='
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Arrow, // '->'
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Float(&'a str), // Floating point immediate
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Integer(&'a str), // Integer immediate
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Type(types::Type), // i32, f32, b32x4, ...
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Value(Value), // v12, vx7
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Ebb(Ebb), // ebb3
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StackSlot(u32), // ss3
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JumpTable(u32), // jt2
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FuncRef(u32), // fn2
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SigRef(u32), // sig2
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Identifier(&'a str), // Unrecognized identifier (opcode, enumerator, ...)
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}
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/// A `Token` with an associated location.
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#[derive(Debug, PartialEq, Eq)]
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pub struct LocatedToken<'a> {
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pub token: Token<'a>,
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pub location: Location,
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}
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/// Wrap up a `Token` with the given location.
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fn token<'a>(token: Token<'a>, loc: Location) -> Result<LocatedToken<'a>, LocatedError> {
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Ok(LocatedToken {
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token: token,
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location: loc,
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})
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}
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/// An error from the lexical analysis.
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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pub enum Error {
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InvalidChar,
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}
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/// An `Error` with an associated Location.
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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pub struct LocatedError {
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pub error: Error,
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pub location: Location,
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}
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/// Wrap up an `Error` with the given location.
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fn error<'a>(error: Error, loc: Location) -> Result<LocatedToken<'a>, LocatedError> {
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Err(LocatedError {
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error: error,
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location: loc,
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})
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}
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/// Get the number of decimal digits at the end of `s`.
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fn trailing_digits(s: &str) -> usize {
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// It's faster to iterate backwards over bytes, and we're only counting ASCII digits.
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s.as_bytes().iter().rev().cloned().take_while(|&b| b'0' <= b && b <= b'9').count()
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}
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/// Pre-parse a supposed entity name by splitting it into two parts: A head of lowercase ASCII
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/// letters and numeric tail.
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pub fn split_entity_name(name: &str) -> Option<(&str, u32)> {
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let (head, tail) = name.split_at(name.len() - trailing_digits(name));
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if tail.len() > 1 && tail.starts_with('0') {
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None
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} else {
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tail.parse().ok().map(|n| (head, n))
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}
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}
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/// Lexical analysis.
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///
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/// A `Lexer` reads text from a `&str` and provides a sequence of tokens.
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///
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/// Also keep track of a line number for error reporting.
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///
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pub struct Lexer<'a> {
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// Complete source being processed.
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source: &'a str,
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// Iterator into `source`.
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chars: CharIndices<'a>,
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// Next character to be processed, or `None` at the end.
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lookahead: Option<char>,
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// Index into `source` of lookahead character.
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pos: usize,
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// Current line number.
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line_number: usize,
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}
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impl<'a> Lexer<'a> {
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pub fn new(s: &'a str) -> Lexer {
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let mut lex = Lexer {
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source: s,
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chars: s.char_indices(),
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lookahead: None,
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pos: 0,
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line_number: 1,
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};
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// Advance to the first char.
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lex.next_ch();
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lex
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}
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// Advance to the next character.
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// Return the next lookahead character, or None when the end is encountered.
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// Always update cur_ch to reflect
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fn next_ch(&mut self) -> Option<char> {
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if self.lookahead == Some('\n') {
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self.line_number += 1;
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}
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match self.chars.next() {
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Some((idx, ch)) => {
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self.pos = idx;
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self.lookahead = Some(ch);
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}
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None => {
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self.pos = self.source.len();
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self.lookahead = None;
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}
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}
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self.lookahead
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}
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// Get the location corresponding to `lookahead`.
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fn loc(&self) -> Location {
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Location { line_number: self.line_number }
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}
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// Starting from `lookahead`, are we looking at `prefix`?
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fn looking_at(&self, prefix: &str) -> bool {
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self.source[self.pos..].starts_with(prefix)
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}
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// Scan a single-char token.
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fn scan_char(&mut self, tok: Token<'a>) -> Result<LocatedToken<'a>, LocatedError> {
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assert!(self.lookahead != None);
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let loc = self.loc();
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self.next_ch();
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token(tok, loc)
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}
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// Scan a multi-char token.
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fn scan_chars(&mut self,
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count: usize,
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tok: Token<'a>)
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-> Result<LocatedToken<'a>, LocatedError> {
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let loc = self.loc();
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for _ in 0..count {
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assert!(self.lookahead != None);
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self.next_ch();
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}
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token(tok, loc)
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}
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/// Get the rest of the current line.
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/// The next token returned by `next()` will be from the following lines.
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pub fn rest_of_line(&mut self) -> &'a str {
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let begin = self.pos;
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loop {
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match self.next_ch() {
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None | Some('\n') => return &self.source[begin..self.pos],
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_ => {}
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}
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}
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}
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// Scan a comment extending to the end of the current line.
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fn scan_comment(&mut self) -> Result<LocatedToken<'a>, LocatedError> {
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let loc = self.loc();
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let text = self.rest_of_line();
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return token(Token::Comment(text), loc);
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}
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// Scan a number token which can represent either an integer or floating point number.
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//
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// Accept the following forms:
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//
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// - `10`: Integer
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// - `-10`: Integer
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// - `0xff_00`: Integer
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// - `0.0`: Float
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// - `0x1.f`: Float
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// - `-0x2.4`: Float
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// - `0x0.4p-34`: Float
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//
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// This function does not filter out all invalid numbers. It depends in the context-sensitive
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// decoding of the text for that. For example, the number of allowed digits an an Ieee32` and
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// an `Ieee64` constant are different.
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fn scan_number(&mut self) -> Result<LocatedToken<'a>, LocatedError> {
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let begin = self.pos;
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let loc = self.loc();
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let mut is_float = false;
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// Skip a leading sign.
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if self.lookahead == Some('-') {
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self.next_ch();
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}
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// Check for NaNs with payloads.
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if self.looking_at("NaN:") || self.looking_at("sNaN:") {
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// Skip the `NaN:` prefix, the loop below won't accept it.
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// We expect a hexadecimal number to follow the colon.
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while self.next_ch() != Some(':') {}
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is_float = true;
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} else if self.looking_at("NaN") || self.looking_at("Inf") {
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// This is Inf or a default quiet NaN.
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is_float = true;
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}
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// Look for the end of this number. Detect the radix point if there is one.
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loop {
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match self.next_ch() {
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Some('-') | Some('_') => {}
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Some('.') => is_float = true,
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Some(ch) if ch.is_alphanumeric() => {}
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_ => break,
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}
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}
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let text = &self.source[begin..self.pos];
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if is_float {
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token(Token::Float(text), loc)
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} else {
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token(Token::Integer(text), loc)
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}
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}
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// Scan a 'word', which is an identifier-like sequence of characters beginning with '_' or an
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// alphabetic char, followed by zero or more alphanumeric or '_' characters.
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fn scan_word(&mut self) -> Result<LocatedToken<'a>, LocatedError> {
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let begin = self.pos;
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let loc = self.loc();
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assert!(self.lookahead == Some('_') || self.lookahead.unwrap().is_alphabetic());
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loop {
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match self.next_ch() {
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Some('_') => {}
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Some(ch) if ch.is_alphanumeric() => {}
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_ => break,
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}
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}
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let text = &self.source[begin..self.pos];
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// Look for numbered well-known entities like ebb15, v45, ...
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token(split_entity_name(text)
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.and_then(|(prefix, number)| {
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Self::numbered_entity(prefix, number)
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.or_else(|| Self::value_type(text, prefix, number))
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})
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.unwrap_or(Token::Identifier(text)),
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loc)
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}
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// If prefix is a well-known entity prefix and suffix is a valid entity number, return the
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// decoded token.
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fn numbered_entity(prefix: &str, number: u32) -> Option<Token<'a>> {
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match prefix {
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"v" => Value::direct_with_number(number).map(|v| Token::Value(v)),
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"vx" => Value::table_with_number(number).map(|v| Token::Value(v)),
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"ebb" => Ebb::with_number(number).map(|ebb| Token::Ebb(ebb)),
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"ss" => Some(Token::StackSlot(number)),
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"jt" => Some(Token::JumpTable(number)),
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"fn" => Some(Token::FuncRef(number)),
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"sig" => Some(Token::SigRef(number)),
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_ => None,
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}
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}
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// Recognize a scalar or vector type.
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fn value_type(text: &str, prefix: &str, number: u32) -> Option<Token<'a>> {
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let is_vector = prefix.ends_with('x');
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let scalar = if is_vector {
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&prefix[0..prefix.len() - 1]
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} else {
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text
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};
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let base_type = match scalar {
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"i8" => types::I8,
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"i16" => types::I16,
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"i32" => types::I32,
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"i64" => types::I64,
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"f32" => types::F32,
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"f64" => types::F64,
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"b1" => types::B1,
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"b8" => types::B8,
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"b16" => types::B16,
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"b32" => types::B32,
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"b64" => types::B64,
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_ => return None,
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};
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if is_vector {
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if number <= u16::MAX as u32 {
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base_type.by(number as u16).map(|t| Token::Type(t))
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} else {
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None
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}
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} else {
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Some(Token::Type(base_type))
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}
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}
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/// Get the next token or a lexical error.
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///
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/// Return None when the end of the source is encountered.
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pub fn next(&mut self) -> Option<Result<LocatedToken<'a>, LocatedError>> {
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loop {
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let loc = self.loc();
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return match self.lookahead {
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None => None,
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Some(';') => Some(self.scan_comment()),
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Some('(') => Some(self.scan_char(Token::LPar)),
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Some(')') => Some(self.scan_char(Token::RPar)),
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Some('{') => Some(self.scan_char(Token::LBrace)),
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Some('}') => Some(self.scan_char(Token::RBrace)),
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Some(',') => Some(self.scan_char(Token::Comma)),
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Some('.') => Some(self.scan_char(Token::Dot)),
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Some(':') => Some(self.scan_char(Token::Colon)),
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Some('=') => Some(self.scan_char(Token::Equal)),
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Some('-') => {
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if self.looking_at("->") {
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Some(self.scan_chars(2, Token::Arrow))
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} else {
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Some(self.scan_number())
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}
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}
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Some(ch) if ch.is_digit(10) => Some(self.scan_number()),
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Some(ch) if ch.is_alphabetic() => Some(self.scan_word()),
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Some(ch) if ch.is_whitespace() => {
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self.next_ch();
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continue;
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}
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_ => {
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// Skip invalid char, return error.
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self.next_ch();
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Some(error(Error::InvalidChar, loc))
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}
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};
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use super::trailing_digits;
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use super::*;
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use cretonne::ir::types;
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use cretonne::ir::{Value, Ebb};
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use error::Location;
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#[test]
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fn digits() {
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assert_eq!(trailing_digits(""), 0);
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assert_eq!(trailing_digits("x"), 0);
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assert_eq!(trailing_digits("0x"), 0);
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assert_eq!(trailing_digits("x1"), 1);
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assert_eq!(trailing_digits("1x1"), 1);
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assert_eq!(trailing_digits("1x01"), 2);
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}
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#[test]
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fn entity_name() {
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assert_eq!(split_entity_name(""), None);
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assert_eq!(split_entity_name("x"), None);
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assert_eq!(split_entity_name("x+"), None);
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assert_eq!(split_entity_name("x+1"), Some(("x+", 1)));
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assert_eq!(split_entity_name("x-1"), Some(("x-", 1)));
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assert_eq!(split_entity_name("1"), Some(("", 1)));
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assert_eq!(split_entity_name("x1"), Some(("x", 1)));
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assert_eq!(split_entity_name("xy0"), Some(("xy", 0)));
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// Reject this non-canonical form.
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assert_eq!(split_entity_name("inst01"), None);
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}
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fn token<'a>(token: Token<'a>, line: usize) -> Option<Result<LocatedToken<'a>, LocatedError>> {
|
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Some(super::token(token, Location { line_number: line }))
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}
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||||
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fn error<'a>(error: Error, line: usize) -> Option<Result<LocatedToken<'a>, LocatedError>> {
|
||||
Some(super::error(error, Location { line_number: line }))
|
||||
}
|
||||
|
||||
#[test]
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||||
fn make_lexer() {
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||||
let mut l1 = Lexer::new("");
|
||||
let mut l2 = Lexer::new(" ");
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let mut l3 = Lexer::new("\n ");
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||||
|
||||
assert_eq!(l1.next(), None);
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assert_eq!(l2.next(), None);
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assert_eq!(l3.next(), None);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn lex_comment() {
|
||||
let mut lex = Lexer::new("; hello");
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||||
assert_eq!(lex.next(), token(Token::Comment("; hello"), 1));
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||||
assert_eq!(lex.next(), None);
|
||||
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||||
lex = Lexer::new("\n ;hello\n;foo");
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assert_eq!(lex.next(), token(Token::Comment(";hello"), 2));
|
||||
assert_eq!(lex.next(), token(Token::Comment(";foo"), 3));
|
||||
assert_eq!(lex.next(), None);
|
||||
|
||||
// Scan a comment after an invalid char.
|
||||
let mut lex = Lexer::new("#; hello");
|
||||
assert_eq!(lex.next(), error(Error::InvalidChar, 1));
|
||||
assert_eq!(lex.next(), token(Token::Comment("; hello"), 1));
|
||||
assert_eq!(lex.next(), None);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn lex_chars() {
|
||||
let mut lex = Lexer::new("(); hello\n = :{, }.");
|
||||
assert_eq!(lex.next(), token(Token::LPar, 1));
|
||||
assert_eq!(lex.next(), token(Token::RPar, 1));
|
||||
assert_eq!(lex.next(), token(Token::Comment("; hello"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Equal, 2));
|
||||
assert_eq!(lex.next(), token(Token::Colon, 2));
|
||||
assert_eq!(lex.next(), token(Token::LBrace, 2));
|
||||
assert_eq!(lex.next(), token(Token::Comma, 2));
|
||||
assert_eq!(lex.next(), token(Token::RBrace, 2));
|
||||
assert_eq!(lex.next(), token(Token::Dot, 2));
|
||||
assert_eq!(lex.next(), None);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn lex_numbers() {
|
||||
let mut lex = Lexer::new(" 0 2_000 -1,0xf -0x0 0.0 0x0.4p-34");
|
||||
assert_eq!(lex.next(), token(Token::Integer("0"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Integer("2_000"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Integer("-1"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Comma, 1));
|
||||
assert_eq!(lex.next(), token(Token::Integer("0xf"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Integer("-0x0"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Float("0.0"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Float("0x0.4p-34"), 1));
|
||||
assert_eq!(lex.next(), None);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn lex_identifiers() {
|
||||
let mut lex = Lexer::new("v0 v00 vx01 ebb1234567890 ebb5234567890 v1x vx1 vxvx4 \
|
||||
function0 function b1 i32x4 f32x5");
|
||||
assert_eq!(lex.next(),
|
||||
token(Token::Value(Value::direct_with_number(0).unwrap()), 1));
|
||||
assert_eq!(lex.next(), token(Token::Identifier("v00"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Identifier("vx01"), 1));
|
||||
assert_eq!(lex.next(),
|
||||
token(Token::Ebb(Ebb::with_number(1234567890).unwrap()), 1));
|
||||
assert_eq!(lex.next(), token(Token::Identifier("ebb5234567890"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Identifier("v1x"), 1));
|
||||
assert_eq!(lex.next(),
|
||||
token(Token::Value(Value::table_with_number(1).unwrap()), 1));
|
||||
assert_eq!(lex.next(), token(Token::Identifier("vxvx4"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Identifier("function0"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Identifier("function"), 1));
|
||||
assert_eq!(lex.next(), token(Token::Type(types::B1), 1));
|
||||
assert_eq!(lex.next(), token(Token::Type(types::I32.by(4).unwrap()), 1));
|
||||
assert_eq!(lex.next(), token(Token::Identifier("f32x5"), 1));
|
||||
assert_eq!(lex.next(), None);
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user