liveness.rs 17.7 KB
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extern crate nalgebra;

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use compiler::machine_code::CompiledFunction;
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use ast::ir::*;
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use ast::types;
use compiler::backend;
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use utils::vec_utils;
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use utils::LinkedHashSet;
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use std::collections::LinkedList;
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use std::collections::{HashMap, HashSet};

use self::nalgebra::DMatrix;

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#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub struct Node(usize);
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#[derive(Clone, Debug, PartialEq)]
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pub struct NodeProperty {
    color: Option<MuID>,
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    group: backend::RegGroup,
    temp: MuID,
    spill_cost: f32
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}
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub struct Move{pub from: Node, pub to: Node}
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pub struct InterferenceGraph {
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    nodes: HashMap<MuID, Node>,
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    nodes_property: HashMap<Node, NodeProperty>,
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    matrix: Option<DMatrix<bool>>,
    
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    moves: HashSet<Move>,
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}

impl InterferenceGraph {
    fn new() -> InterferenceGraph {
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        InterferenceGraph {
            nodes: HashMap::new(),
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            nodes_property: HashMap::new(),
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            matrix: None,
            moves: HashSet::new()
        }
    }
    
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    fn new_node(&mut self, reg_id: MuID, context: &FunctionContext) -> Node {
        let entry = context.get_value(reg_id).unwrap();
        
        if !self.nodes.contains_key(&reg_id) {
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            let index = self.nodes.len();
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            let node = Node(index);
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            // add the node
            self.nodes.insert(reg_id, node.clone());
            
            // add node property
            let group = {
                let ref ty = entry.ty;
                if types::is_scalar(ty) {
                    if types::is_fp(ty) {
                        backend::RegGroup::FPR
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                    } else {
                        backend::RegGroup::GPR
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                    }
                } else {
                    unimplemented!()
                }
            };
            let property = NodeProperty {
                color: None,
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                group: group,
                temp: reg_id,
                spill_cost: 0.0f32
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            };
            self.nodes_property.insert(node, property);
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        } 
        
        
        let node = * self.nodes.get(&reg_id).unwrap();
        
        // increase node spill cost
        let property = self.nodes_property.get_mut(&node).unwrap();
        property.spill_cost += 1.0f32;
        
        node
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    }
    
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    pub fn get_node(&self, reg: MuID) -> Node {
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        match self.nodes.get(&reg) {
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            Some(index) => *index,
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            None => panic!("do not have a node for {}", reg)
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        }
    }
    
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    pub fn temps(&self) -> Vec<MuID>{
        let mut ret = vec![];
        for reg in self.nodes.keys() {
            ret.push(*reg);
        }
        ret
    }
    
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    pub fn nodes(&self) -> Vec<Node> {
        let mut ret = vec![];
        for node in self.nodes.values() {
            ret.push(node.clone());
        }
        ret
    }
    
    pub fn moves(&self) -> &HashSet<Move> {
        &self.moves
    }
    
    pub fn n_nodes(&self) -> usize {
        self.nodes.len()
    }
    
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    fn init_graph(&mut self) {
        let len = self.nodes.len();
        self.matrix = Some(DMatrix::from_element(len, len, false));
    }
    
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    fn add_move(&mut self, src: Node, dst: Node) {
        self.moves.insert(Move{from: src, to: dst});
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    }
    
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    pub fn add_interference_edge(&mut self, from: Node, to: Node) {
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        // only if two nodes are from the same RegGroup,
        // they may interefere
        if self.nodes_property.get(&from).unwrap().group 
           == self.nodes_property.get(&to).unwrap().group {
            self.matrix.as_mut().unwrap()[(from.0, to.0)] = true;
        }
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    }
    
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    pub fn color_node(&mut self, node: Node, color: MuID) {
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        self.nodes_property.get_mut(&node).unwrap().color = Some(color);
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    }
    
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    pub fn is_colored(&self, node: Node) -> bool {
        self.nodes_property.get(&node).unwrap().color.is_some()
    }
    
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    pub fn get_color_of(&self, node: Node) -> Option<MuID> {
        self.nodes_property.get(&node).unwrap().color
    }
    
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    pub fn get_group_of(&self, node: Node) -> backend::RegGroup {
        self.nodes_property.get(&node).unwrap().group
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    }
    
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    pub fn get_temp_of(&self, node: Node) -> MuID {
        self.nodes_property.get(&node).unwrap().temp
    }
    
    pub fn get_spill_cost(&self, node: Node) -> f32 {
        self.nodes_property.get(&node).unwrap().spill_cost
    }
    
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    fn is_same_node(&self, node1: Node, node2: Node) -> bool {
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        node1 == node2
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    }
    
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    pub fn is_adj(&self, from: Node, to: Node) -> bool {
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        let ref matrix = self.matrix.as_ref().unwrap();
        
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        matrix[(from.0, to.0)] || matrix[(to.0, from.0)]
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    }
    
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    pub fn outedges_of(&self, node: Node) -> Vec<Node> {
        let mut ret = vec![];
        let matrix = self.matrix.as_ref().unwrap();
        
        for i in 0..self.nodes.len() {
            if matrix[(node.0, i)] {
                ret.push(Node(i));
            }
        }
        
        ret
    }
    
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    pub fn outdegree_of(&self, node: Node) -> usize {
        let mut count = 0;
        for i in 0..self.nodes.len() {
            if self.matrix.as_ref().unwrap()[(node.0, i)] {
                count += 1;
            }
        }
        
        count
    }
    
    pub fn indegree_of(&self, node: Node) -> usize {
        let mut count = 0;
        for i in 0..self.nodes.len() {
            if self.matrix.as_ref().unwrap()[(i, node.0)] {
                count += 1;
            }
        }
        
        count
    }
    
    pub fn degree_of(&self, node: Node) -> usize {
        self.outdegree_of(node) + self.indegree_of(node)
    }
    
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    pub fn print(&self) {
        println!("");
        println!("Interference Graph");

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        println!("nodes:");
        for id in self.nodes.keys() {
            println!("Reg {} -> {:?}", id, self.nodes.get(&id).unwrap());
        }

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        println!("color:");
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        for (n, c) in self.nodes_property.iter() {
            println!("{:?} -> Color/Reg {:?}", n, c);
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        }
        println!("moves:");
        for mov in self.moves.iter() {
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            println!("Move {:?} -> {:?}", mov.from, mov.to);
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        }
        println!("graph:");
        {
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            let node_to_reg_id = {
                let mut ret : HashMap<Node, MuID> = HashMap::new();
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                for reg in self.nodes.keys() {
                    ret.insert(*self.nodes.get(reg).unwrap(), *reg);
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                }
                
                ret 
            };
            
            let matrix = self.matrix.as_ref().unwrap();
            for i in 0..matrix.ncols() {
                for j in 0..matrix.nrows() {
                    if matrix[(i, j)] {
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                        let from_node = node_to_reg_id.get(&Node(i)).unwrap();
                        let to_node = node_to_reg_id.get(&Node(j)).unwrap();
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                        println!("Reg {} -> Reg {}", from_node, to_node);
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                    }
                }
            }
        }
        println!("");
    }
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}

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pub fn is_machine_reg(reg: MuID) -> bool {
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    if reg < MACHINE_ID_END {
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        true
    } else {
        false
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    }
}

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#[allow(unused_variables)]
fn build_live_set(cf: &mut CompiledFunction, func: &MuFunctionVersion) {
    let n_insts = cf.mc.number_of_insts();
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    let mut livein  : Vec<Vec<MuID>> = vec![vec![]; n_insts];
    let mut liveout : Vec<Vec<MuID>> = vec![vec![]; n_insts];    
    
    let mut is_changed = true;
    
    while is_changed {
        // reset
        is_changed = false;
        
        for n in 0..n_insts {
            let in_set_old = livein[n].to_vec(); // copy to new vec
            let out_set_old = liveout[n].to_vec();
            
            // in[n] <- use[n] + (out[n] - def[n])
            // (1) in[n] = use[n]
            let mut in_set_new = vec![];
            in_set_new.extend_from_slice(&cf.mc.get_inst_reg_uses(n));
            // (2) diff = out[n] - def[n]
            let mut diff = liveout[n].to_vec();
            for def in cf.mc.get_inst_reg_defines(n) {
                vec_utils::remove_value(&mut diff, *def);
            }
            // (3) in[n] = in[n] + diff
            vec_utils::append_unique(&mut in_set_new, &mut diff);
            
            // update livein[n]
            livein[n].clear();
            livein[n].extend_from_slice(&in_set_new);
            
            // out[n] <- union(in[s] for every successor s of n)
            let mut union = vec![];
            for s in cf.mc.get_succs(n) {
                vec_utils::append_clone_unique(&mut union, &livein[*s]);
            }
            
            // update liveout[n]
            liveout[n].clear();
            liveout[n].extend_from_slice(&union);
            
            let n_changed = !vec_utils::is_identical_ignore_order(&livein[n], &in_set_old)
                || !vec_utils::is_identical_ignore_order(&liveout[n], &out_set_old);
            is_changed = is_changed || n_changed;
        }
    }
    
    for block in cf.mc.get_all_blocks().to_vec() {
        if cf.mc.get_ir_block_livein(&block).is_none() {
            let start_inst = cf.mc.get_block_range(&block).unwrap().start;
            cf.mc.set_ir_block_livein(&block, livein[start_inst].to_vec());
        }
        
        if cf.mc.get_ir_block_liveout(&block).is_none() {
            let end_inst = cf.mc.get_block_range(&block).unwrap().end;
            cf.mc.set_ir_block_liveout(&block, liveout[end_inst].to_vec());
        }
    }
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}

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// from Tailoring Graph-coloring Register Allocation For Runtime Compilation, Figure 4
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pub fn build_chaitin_briggs (cf: &mut CompiledFunction, func: &MuFunctionVersion) -> InterferenceGraph {
    build_live_set(cf, func);
    
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    let mut ig = InterferenceGraph::new();
    
    // precolor machine register nodes
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    for reg in backend::all_regs().values() {
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        let reg_id = reg.extract_ssa_id().unwrap();
        let node = ig.new_node(reg_id, &func.context);
        ig.color_node(node, reg_id);
    }
    
    // Initialize and creates nodes for all the involved temps/regs
    for i in 0..cf.mc.number_of_insts() {
        for reg_id in cf.mc.get_inst_reg_defines(i) {
            let reg_id = *reg_id;
            ig.new_node(reg_id, &func.context);
        }
        
        for reg_id in cf.mc.get_inst_reg_uses(i) {
            let reg_id = *reg_id;
            ig.new_node(reg_id, &func.context);
        }
    }
    
    // all nodes has been added, we init graph (create adjacency matrix)
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    ig.init_graph();
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    for block in cf.mc.get_all_blocks() {
        // Current_Live(B) = LiveOut(B)
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        let mut current_live = LinkedHashSet::from_vec(match cf.mc.get_ir_block_liveout(&block) {
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            Some(liveout) => liveout.to_vec(),
            None => panic!("cannot find liveout for block {}", block)
        });
        
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        let range = cf.mc.get_block_range(&block);
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        if range.is_none() {
            continue;
        }
        
        // for every inst I in reverse order
        for i in range.unwrap().rev() {
            let src : Option<MuID> = {
                if cf.mc.is_move(i) {
                    let src = cf.mc.get_inst_reg_uses(i);
                    let dst = cf.mc.get_inst_reg_defines(i);
                    
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                    // src:  reg/imm/mem
                    // dest: reg/mem
                    // we dont care if src/dest is mem
                    if cf.mc.is_using_mem_op(i) {
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                        None
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                    } else {
                        if src.len() == 1 {
                            let node1 = ig.get_node(src[0]);
                            let node2 = ig.get_node(dst[0]);
                            ig.add_move(node1, node2);
                            
                            Some(src[0])
                        } else {
                            None
                        }
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                    }
                } else {
                    None
                }
            };
            
            // for every definition D in I
            for d in cf.mc.get_inst_reg_defines(i) {
                // add an interference from D to every element E in Current_Live - {D}
                // creating nodes if necessary
                for e in current_live.iter() {
                    if src.is_none() || (src.is_some() && *e != src.unwrap()) {
                        let from = ig.get_node(*d);
                        let to = ig.get_node(*e);
                        
                        if !ig.is_same_node(from, to) && !ig.is_adj(from, to) {
                            if !ig.is_colored(from) {
                                ig.add_interference_edge(from, to);
                            }
                            if !ig.is_colored(to) {
                                ig.add_interference_edge(to, from);
                            }
                        }
                    }
                }
            }
            
            // for every definition D in I
            for d in cf.mc.get_inst_reg_defines(i) {
                // remove D from Current_Live
                current_live.remove(d);
            }
            
            // for every use U in I
            for u in cf.mc.get_inst_reg_uses(i) {
                // add U to Current_live
                current_live.insert(*u);
            }
        }
    }
    
    ig
}

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// from tony's code src/RegAlloc/Liveness.java
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// this function is no longer used
#[allow(dead_code)]
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pub fn build (cf: &CompiledFunction, func: &MuFunctionVersion) -> InterferenceGraph {
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    let mut ig = InterferenceGraph::new();
    
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    // precolor machine register nodes
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    for reg in backend::all_regs().values() {
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        let reg_id = reg.extract_ssa_id().unwrap();
        let node = ig.new_node(reg_id, &func.context);
        ig.color_node(node, reg_id);
    }
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    // Liveness Analysis
    let n_insts = cf.mc.number_of_insts();
    let mut live_in : Vec<Vec<MuID>> = vec![vec![]; n_insts];
    let mut live_out : Vec<Vec<MuID>> = vec![vec![]; n_insts];
    let mut work_list : LinkedList<usize> = LinkedList::new();
    
    // Initialize 'in' sets for each node in the flow graph
    // and creates nodes for all the involved temps/regs
    for i in 0..n_insts {
        let ref mut in_set = live_in[i];
        
        for reg_id in cf.mc.get_inst_reg_defines(i) {
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            let reg_id = *reg_id;
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            ig.new_node(reg_id, &func.context);
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        }
        
        for reg_id in cf.mc.get_inst_reg_uses(i) {
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            let reg_id = *reg_id;
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            ig.new_node(reg_id, &func.context);
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            in_set.push(reg_id);
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        }
        
        work_list.push_front(i);
    }
    
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    // all nodes has been added, we init graph (create adjacency matrix)
    ig.init_graph();
    
    // compute liveIn and liveOut iteratively
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    trace!("build live outs");
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    while !work_list.is_empty() {
        let n = work_list.pop_front().unwrap();
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        trace!("build liveout for #{}", n);
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        let ref mut out_set = live_out[n];
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        // out = union(in[succ]) for all succs
        for succ in cf.mc.get_succs(n) {
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            trace!("add successor's livein {:?} to #{}", &live_in[*succ], n); 
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            vec_utils::add_all(out_set, &live_in[*succ]);
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        }
        
        // in = use(i.e. live_in) + (out - def) 
        let mut diff = out_set.clone();
        for def in cf.mc.get_inst_reg_defines(n) {
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            vec_utils::remove_value(&mut diff, *def);
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            trace!("removing def: {}", *def);
            trace!("diff = {:?}", diff);
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        }
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        trace!("out - def = {:?}", diff);
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        if !diff.is_empty() {
            let ref mut in_set = live_in[n];
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            trace!("in = (use) {:?}", in_set);
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            if vec_utils::add_all(in_set, &diff) {
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                for p in cf.mc.get_preds(n) {
                    work_list.push_front(*p);
                }
            }
        }
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        trace!("in = use + (out - def) = {:?}", live_in[n]);
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    }
    
    // debug live-outs
    if cfg!(debug_assertions) {
        trace!("check live-outs");
        for n in 0..n_insts {
            let ref mut live = live_out[n];
            trace!("#{}\t{:?}", n, live);
        }
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    }
    
    // build interference graph
    for n in 0..n_insts {
        let ref mut live = live_out[n];
        
        let src : Option<MuID> = {
            if cf.mc.is_move(n) {
                let src = cf.mc.get_inst_reg_uses(n);
                let dst = cf.mc.get_inst_reg_defines(n);
                
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                // src may be an immediate number
                // but dest is definitly a register
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                debug_assert!(dst.len() == 1);
                
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                if src.len() == 1 {
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                    let node1 = ig.get_node(src[0]);
                    let node2 = ig.get_node(dst[0]);
                    ig.add_move(node1, node2);
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                    Some(src[0])
                } else {
                    None
                }
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            } else {
                None
            }
        };
        
        for d in cf.mc.get_inst_reg_defines(n) {
            for t in live.iter() {
                if src.is_none() || (src.is_some() && *t != src.unwrap()) {
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                    let from = ig.get_node(*d);
                    let to = ig.get_node(*t);
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                    if !ig.is_same_node(from, to) && !ig.is_adj(from, to) {
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                        if !ig.is_colored(from) {
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                            ig.add_interference_edge(from, to);
                        }
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                        if !ig.is_colored(to) {
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                            ig.add_interference_edge(to, from);
                        }
                    }
                }
            }
        }
        
        for d in cf.mc.get_inst_reg_defines(n) {
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            vec_utils::remove_value(live, *d);
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        }
        
        for u in cf.mc.get_inst_reg_uses(n) {
            live.push(*u);
        }
    }
    
    ig
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}