59 lines
1.9 KiB
Rust
59 lines
1.9 KiB
Rust
//! Register allocator context.
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//!
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//! The `Context` struct contains data structures that should be preserved across invocations of
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//! the register allocator algorithm. This doesn't preserve any data between functions, but it
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//! avoids allocating data structures independently for each function begin compiled.
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use dominator_tree::DominatorTree;
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use flowgraph::ControlFlowGraph;
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use ir::Function;
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use isa::TargetIsa;
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use regalloc::coloring::Coloring;
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use regalloc::live_value_tracker::LiveValueTracker;
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use regalloc::liveness::Liveness;
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/// Persistent memory allocations for register allocation.
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pub struct Context {
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liveness: Liveness,
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tracker: LiveValueTracker,
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coloring: Coloring,
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}
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impl Context {
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/// Create a new context for register allocation.
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///
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/// This context should be reused for multiple functions in order to avoid repeated memory
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/// allocations.
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pub fn new() -> Context {
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Context {
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liveness: Liveness::new(),
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tracker: LiveValueTracker::new(),
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coloring: Coloring::new(),
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}
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}
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/// Allocate registers in `func`.
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///
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/// After register allocation, all values in `func` have been assigned to a register or stack
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/// location that is consistent with instruction encoding constraints.
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pub fn run(&mut self,
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isa: &TargetIsa,
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func: &mut Function,
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cfg: &ControlFlowGraph,
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domtree: &DominatorTree) {
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// `Liveness` and `Coloring` are self-clearing.
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// Tracker state (dominator live sets) is actually reused between the spilling and coloring
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// phases.
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self.tracker.clear();
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// First pass: Liveness analysis.
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self.liveness.compute(isa, func, cfg);
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// TODO: Second pass: Spilling.
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// Third pass: Reload and coloring.
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self.coloring
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.run(isa, func, domtree, &mut self.liveness, &mut self.tracker);
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}
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}
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