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const std = @import("std");
const jv = @import("../jv.zig");
const Ast = @import("./parse.zig").Ast;
const BinaryOp = @import("./parse.zig").BinaryOp;
pub const ConstIndex = enum(u32) { _ };
pub const Opcode = enum {
nop,
ret,
jump,
jump_unless,
fork,
dup,
pop,
subexp_begin,
subexp_end,
index,
index_opt,
add,
sub,
mul,
div,
mod,
eq,
ne,
lt,
gt,
le,
ge,
@"const",
const_true,
const_false,
};
pub const Instr = union(Opcode) {
const Self = @This();
nop,
ret,
jump: usize,
jump_unless: usize,
fork: usize,
dup,
pop,
subexp_begin,
subexp_end,
index,
index_opt,
add,
sub,
mul,
div,
mod,
eq,
ne,
lt,
gt,
le,
ge,
@"const": ConstIndex,
const_true,
const_false,
pub fn op(self: Self) Opcode {
return self;
}
};
fn compileExpr(allocator: std.mem.Allocator, compile_allocator: std.mem.Allocator, ast: *const Ast) ![]Instr {
var instrs = try std.ArrayList(Instr).initCapacity(allocator, 16);
switch (ast.*) {
.identity => try instrs.append(allocator, .nop),
.index => |idx| {
const base_instrs = try compileExpr(allocator, compile_allocator, idx.base);
defer allocator.free(base_instrs);
const index_instrs = try compileExpr(allocator, compile_allocator, idx.index);
defer allocator.free(index_instrs);
try instrs.appendSlice(allocator, base_instrs);
try instrs.append(allocator, .subexp_begin);
try instrs.appendSlice(allocator, index_instrs);
try instrs.append(allocator, .subexp_end);
try instrs.append(allocator, if (idx.is_optional) .index_opt else .index);
},
.literal => |idx| try instrs.append(allocator, .{ .@"const" = idx }),
.binary_expr => |binary_expr| {
const rhs_instrs = try compileExpr(allocator, compile_allocator, binary_expr.rhs);
defer allocator.free(rhs_instrs);
const lhs_instrs = try compileExpr(allocator, compile_allocator, binary_expr.lhs);
defer allocator.free(lhs_instrs);
try instrs.append(allocator, .subexp_begin);
try instrs.appendSlice(allocator, rhs_instrs);
try instrs.append(allocator, .subexp_end);
try instrs.append(allocator, .subexp_begin);
try instrs.appendSlice(allocator, lhs_instrs);
try instrs.append(allocator, .subexp_end);
const op_instr: Instr = switch (binary_expr.op) {
.add => .add,
.sub => .sub,
.mul => .mul,
.div => .div,
.mod => .mod,
.eq => .eq,
.ne => .ne,
.lt => .lt,
.gt => .gt,
.le => .le,
.ge => .ge,
else => return error.Unimplemented,
};
try instrs.append(allocator, op_instr);
},
.and_expr => |and_expr| {
// DUP
// <lhs>
// JUMP_UNLESS l3
// POP
// <rhs>
// JUMP_UNLESS l1
// CONST_TRUE
// JUMP l2
// l1: CONST_FALSE
// l2: JUMP l4
// l3: POP
// CONST_FALSE
// l4:
const lhs_instrs = try compileExpr(allocator, compile_allocator, and_expr.lhs);
defer allocator.free(lhs_instrs);
const rhs_instrs = try compileExpr(allocator, compile_allocator, and_expr.rhs);
defer allocator.free(rhs_instrs);
try instrs.append(allocator, .dup);
try instrs.appendSlice(allocator, lhs_instrs);
const jump1_idx = instrs.items.len;
try instrs.append(allocator, .{ .jump_unless = 0 });
try instrs.append(allocator, .pop);
try instrs.appendSlice(allocator, rhs_instrs);
const jump2_idx = instrs.items.len;
try instrs.append(allocator, .{ .jump_unless = 0 });
try instrs.append(allocator, .const_true);
const jump3_idx = instrs.items.len;
try instrs.append(allocator, .{ .jump = 0 });
const l1 = instrs.items.len;
try instrs.append(allocator, .const_false);
const jump4_idx = instrs.items.len;
const l2 = instrs.items.len;
try instrs.append(allocator, .{ .jump = 0 });
const l3 = instrs.items.len;
try instrs.append(allocator, .pop);
try instrs.append(allocator, .const_false);
const l4 = instrs.items.len;
instrs.items[jump1_idx] = .{ .jump_unless = l3 - jump1_idx };
instrs.items[jump2_idx] = .{ .jump_unless = l1 - jump2_idx };
instrs.items[jump3_idx] = .{ .jump = l2 - jump3_idx };
instrs.items[jump4_idx] = .{ .jump = l4 - jump4_idx };
},
.or_expr => |or_expr| {
// DUP
// <lhs>
// JUMP_UNLESS l1
// POP
// CONST_TRUE
// JUMP l3
// l1: POP
// <rhs>
// JUMP_UNLESS l2
// CONST_TRUE
// JUMP l3
// l2: CONST_FALSE
// l3:
const lhs_instrs = try compileExpr(allocator, compile_allocator, or_expr.lhs);
defer allocator.free(lhs_instrs);
const rhs_instrs = try compileExpr(allocator, compile_allocator, or_expr.rhs);
defer allocator.free(rhs_instrs);
try instrs.append(allocator, .dup);
try instrs.appendSlice(allocator, lhs_instrs);
const jump1_idx = instrs.items.len;
try instrs.append(allocator, .{ .jump_unless = 0 });
try instrs.append(allocator, .pop);
try instrs.append(allocator, .const_true);
const jump2_idx = instrs.items.len;
try instrs.append(allocator, .{ .jump = 0 });
const l1 = instrs.items.len;
try instrs.append(allocator, .pop);
try instrs.appendSlice(allocator, rhs_instrs);
const jump3_idx = instrs.items.len;
try instrs.append(allocator, .{ .jump_unless = 0 });
try instrs.append(allocator, .const_true);
const jump4_idx = instrs.items.len;
try instrs.append(allocator, .{ .jump = 0 });
const l2 = instrs.items.len;
try instrs.append(allocator, .const_false);
const l3 = instrs.items.len;
instrs.items[jump1_idx] = .{ .jump_unless = l1 - jump1_idx };
instrs.items[jump2_idx] = .{ .jump = l3 - jump2_idx };
instrs.items[jump3_idx] = .{ .jump_unless = l2 - jump3_idx };
instrs.items[jump4_idx] = .{ .jump = l3 - jump4_idx };
},
.pipe => |pipe_expr| {
const lhs_instrs = try compileExpr(allocator, compile_allocator, pipe_expr.lhs);
defer allocator.free(lhs_instrs);
const rhs_instrs = try compileExpr(allocator, compile_allocator, pipe_expr.rhs);
defer allocator.free(rhs_instrs);
try instrs.appendSlice(allocator, lhs_instrs);
try instrs.appendSlice(allocator, rhs_instrs);
},
.comma => |comma_expr| {
// FORK l1
// <lhs>
// JUMP l2
// l1: <rhs>
// l2:
const lhs_instrs = try compileExpr(allocator, compile_allocator, comma_expr.lhs);
defer allocator.free(lhs_instrs);
const rhs_instrs = try compileExpr(allocator, compile_allocator, comma_expr.rhs);
defer allocator.free(rhs_instrs);
const fork_index = instrs.items.len;
try instrs.append(allocator, .{ .fork = 0 });
try instrs.appendSlice(allocator, lhs_instrs);
const jump_index = instrs.items.len;
try instrs.append(allocator, .{ .jump = 0 });
const l1 = instrs.items.len;
try instrs.appendSlice(allocator, rhs_instrs);
const l2 = instrs.items.len;
instrs.items[fork_index] = .{ .fork = l1 - fork_index };
instrs.items[jump_index] = .{ .jump = l2 - jump_index };
},
}
return instrs.toOwnedSlice(allocator);
}
pub fn compile(allocator: std.mem.Allocator, compile_allocator: std.mem.Allocator, ast: *const Ast) ![]Instr {
var instrs = try std.ArrayList(Instr).initCapacity(allocator, 16);
const expr_instrs = try compileExpr(allocator, compile_allocator, ast);
defer allocator.free(expr_instrs);
try instrs.appendSlice(allocator, expr_instrs);
try instrs.append(allocator, .ret);
return instrs.toOwnedSlice(allocator);
}
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