tiny.choir.backends.aarch64.control

1const std = @import("std");2const ir = @import("../../core/root.zig");3const dialects = @import("../../dialects/root.zig");4const scf = dialects.ScfDialect;56pub const max_depth: usize = 32;7pub const max_carried_values: usize = 16;8pub const max_transfers: usize = max_carried_values + 1;9pub const Kind = enum { conditional, counted, repeated };10pub const Error = error{ ControlShape, ControlType, CarriedCapacity, DepthCapacity };1112pub fn kind(op: *const ir.Operation) ?Kind {13    if (is(op, scf.IfOp.operation_name)) return .conditional;14    if (is(op, scf.ForOp.operation_name)) return .counted;15    if (is(op, scf.WhileOp.operation_name)) return .repeated;16    return null;17}1819pub fn integer(typ: ir.Type) bool {20    const name = typ.getDialectTypeName() orelse return false;21    const scalar = dialects.arith.scalarKindFromTypeName(name) orelse return false;22    return switch (scalar) {23        .i8, .i16, .i32, .i64, .u8, .u16, .u32, .u64, .index, .bool => true,24        else => false,25    };26}2728fn named(typ: ir.Type, name: []const u8) bool {29    return std.mem.eql(u8, typ.getDialectTypeName() orelse "", name);30}3132/// Admission establishes all region/edge shapes before placement or emission.33pub fn validate(op: *ir.Operation, construct: Kind) Error!void {34    const count = op.results.items.len;35    if (count > max_carried_values) return error.CarriedCapacity;36    for (op.results.items) |result| if (!integer(result.type)) return error.ControlType;37    const regions = op.regions.items;38    const expected_regions: usize = if (construct == .counted) 1 else 2;39    if (regions.len != expected_regions) {40        if (!(construct == .conditional and count == 0 and regions.len == 1)) return error.ControlShape;41    }42    for (regions) |*region| {43        if (region.blocks.size != 1) return error.ControlShape;44        const block = region.getEntryBlock() orelse return error.ControlShape;45        if (block.operations.tail == null) return error.ControlShape;46        for (block.arguments.items) |arg| if (!integer(arg.type)) return error.ControlType;47    }48    switch (construct) {49        .conditional => {50            if (op.operands.items.len != 1) return error.ControlShape;51            if (!named(op.operands.items[0].value.type, "arith.bool")) return error.ControlType;52            for (regions) |*region| {53                const block = region.getEntryBlock().?;54                if (block.arguments.items.len != 0) return error.ControlShape;55                try yieldTypes(last(block), op.results.items);56            }57        },58        .counted => {59            if (op.operands.items.len != count + 3) return error.ControlShape;60            for (op.operands.items[0..3]) |operand| if (!named(operand.value.type, "arith.index")) return error.ControlType;61            const block = regions[0].getEntryBlock().?;62            if (block.arguments.items.len != count + 1) return error.ControlShape;63            if (!named(block.arguments.items[0].type, "arith.index")) return error.ControlType;64            for (op.results.items, op.operands.items[3..], block.arguments.items[1..]) |result, init, arg| {65                if (!result.type.eql(init.value.type) or !result.type.eql(arg.type)) return error.ControlType;66            }67            try yieldTypes(last(block), op.results.items);68        },69        .repeated => {70            if (op.operands.items.len != count) return error.ControlShape;71            for (regions) |*region| if (region.getEntryBlock().?.arguments.items.len != count) return error.ControlShape;72            const before = regions[0].getEntryBlock().?;73            const after = regions[1].getEntryBlock().?;74            for (op.results.items, op.operands.items, before.arguments.items, after.arguments.items) |result, init, lhs, rhs| {75                if (!result.type.eql(init.value.type) or !result.type.eql(lhs.type) or !result.type.eql(rhs.type)) return error.ControlType;76            }77            const condition = last(before);78            if (!is(condition, scf.ConditionOp.operation_name) or condition.operands.items.len != count + 1) return error.ControlShape;79            if (!named(condition.operands.items[0].value.type, "arith.bool")) return error.ControlType;80            for (op.results.items, condition.operands.items[1..]) |result, forwarded| if (!result.type.eql(forwarded.value.type)) return error.ControlType;81            try yieldTypes(last(after), op.results.items);82        },83    }84}8586fn yieldTypes(op: *ir.Operation, results: []const ir.Value) Error!void {87    if (!is(op, scf.YieldOp.operation_name) or op.operands.items.len != results.len) return error.ControlShape;88    for (results, op.operands.items) |result, yielded| if (!result.type.eql(yielded.value.type)) return error.ControlType;89}9091/// Compare an operation's registered spelling without requiring registration.92pub fn is(op: *const ir.Operation, name: []const u8) bool {93    return std.mem.eql(u8, op.name.name, name);94}9596pub fn last(block: *ir.Block) *ir.Operation {97    return @ptrCast(@alignCast(block.operations.tail.?));98}

1pub const control = @import("control.zig");