Method parse_basic_block

cranelift/reader/src/parser.rs:2041–2106

Parse a basic block, add contents to `ctx`. extended-basic-block ::= * block-header { instruction } block-header ::= Block(block) [block-params] [block-flags] ":" block-flags ::= [Cold]

(&mut self, ctx: &mut Context)

    // block-flags          ::= [Cold]
    //
    fn parse_basic_block(&mut self, ctx: &mut Context) -> ParseResult<()> {
        // Collect comments for the next block.
        self.start_gathering_comments();

        let block_num = self.match_block("expected block header")?;
        let block = ctx.add_block(block_num, self.loc)?;

        if block_num.as_u32() >= MAX_BLOCKS_IN_A_FUNCTION {
            return Err(self.error("too many blocks"));
        }

        if self.token() == Some(Token::LPar) {
            self.parse_block_params(ctx, block)?;
        }

        if self.optional(Token::Cold) {
            ctx.set_cold_block(block);
        }

        self.match_token(Token::Colon, "expected ':' after block parameters")?;

        // Collect any trailing comments.
        self.token();
        self.claim_gathered_comments(block);

        // extended-basic-block ::= block-header * { instruction }
        while match self.token() {
            Some(Token::Value(_))
            | Some(Token::Identifier(_))
            | Some(Token::LBracket)
            | Some(Token::SourceLoc(_))
            | Some(Token::LAngle) => true,
            _ => false,
        } {
            let srcloc = self.optional_srcloc()?;

            let debug_tags = self.optional_debug_tags()?;

            // We need to parse instruction results here because they are shared
            // between the parsing of value aliases and the parsing of instructions.
            //
            // inst-results ::= Value(v) { "," Value(v) }
            let results = self.parse_inst_results()?;

            for result in &results {
                while ctx.function.dfg.num_values() <= result.index() {
                    ctx.function.dfg.make_invalid_value_for_parser();
                }
            }

            match self.token() {
                Some(Token::Arrow) => {
                    self.consume();
                    self.parse_value_alias(&results, ctx)?;
                }
                Some(Token::Equal) => {
                    self.consume();
                    self.parse_instruction(&results, srcloc, debug_tags, ctx, block)?;