Method check_function

src/debug_utils/validate_func.rs:828–884

Main entry point for `Function` validation.

(&mut self)

    /// Main entry point for `Function` validation.
    fn check_function(&mut self) -> Result<()> {
        self.check_limits()?;

        // Check blocks and instructions. This also records a `ValueDef` for
        // each defined value.
        for block in self.func.blocks() {
            self.check_block(block)?;
        }

        // Check entry points before any CFG traversal uses them.
        let entry_points = self.func.entry_points();
        ensure!(
            !entry_points.is_empty(),
            "Function must have at least one entry point"
        );
        for (i, &entry) in entry_points.iter().enumerate() {
            ensure!(
                !entry_points[..i].contains(&entry),
                "Entry points must not contain duplicates"
            );
            self.check_entity(Entity::Block(entry))?;
            ensure!(
                self.func.block_preds(entry).is_empty(),
                "{entry}: Entry point cannot have predecessors"
            );
            ensure!(
                self.func.block_params(entry).is_empty(),
                "{entry}: Entry point cannot have block parameters"
            );
        }
        // Check that all blocks are reachable.
        let postorder = PostOrder::for_function(self.func);
        if postorder.cfg_postorder().len() != self.func.num_blocks() {
            for block in self.func.blocks() {
                ensure!(
                    postorder.is_reachable(block),
                    "{block} is not reachable from an entry point"
                );
            }

            // There must be at least one unreachable block, so we can't get here.
            unreachable!();
        }

        // Check that defs dominate uses, as required by SSA.
        self.domtree.compute(self.func, &postorder);
        for block in self.func.blocks() {
            self.check_ssa_dominance(block)?;
        }

        // Check values.
        for value in self.func.values() {
            self.check_value(value)?;
        }

        Ok(())
    }
}