Method insert_block

cranelift/codegen/src/cursor.rs:593–607

Insert a block at the current position and switch to it. As far as possible, this method behaves as if the block header were an instruction inserted at the current position. - If the cursor is pointing at an existing instruction, *the current block is split in two and the current instruction becomes the first instruction in the inserted block. - If the cursor points at the bottom of a block, the

(&mut self, new_block: ir::Block)

    /// This means that it is always valid to call this method, and it always leaves the cursor in
    /// a state that will insert instructions into the new block.
    fn insert_block(&mut self, new_block: ir::Block) {
        use self::CursorPosition::*;
        match self.position() {
            At(inst) => {
                self.layout_mut().split_block(new_block, inst);
                // All other cases move to `After(block)`, but in this case we'll stay `At(inst)`.
                return;
            }
            Nowhere => self.layout_mut().append_block(new_block),
            Before(block) => self.layout_mut().insert_block(new_block, block),
            After(block) => self.layout_mut().insert_block_after(new_block, block),
        }
        // For everything but `At(inst)` we end up appending to the new block.
        self.set_position(After(new_block));
    }
}

/// Function cursor.