feat: code generation and execution for simple choice statements
This commit is contained in:
Brett Broadhurst
parent
55346fcd85
commit
889f678dd8
4 changed files with 389 additions and 179 deletions
337
src/AstGen.zig
337
src/AstGen.zig
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@ -18,68 +18,16 @@ jump_stack: std.ArrayListUnmanaged(Jump) = .empty,
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errors: std.ArrayListUnmanaged(Ast.Error) = .empty,
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default_knot_name: [:0]const u8 = "@main@",
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pub const CheckError = anyerror;
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pub const Symbol = union(enum) {
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global_variable: struct {
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is_constant: bool,
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constant_slot: usize,
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node: *const Ast.Node,
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},
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local_variable: struct {
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stack_slot: usize,
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node: *const Ast.Node,
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},
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parameter: struct {
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constant_slot: usize,
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stack_slot: usize,
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},
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pub const CheckError = error{
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OutOfMemory,
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CompilerBug,
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SemanticError,
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TooManyConstants,
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InvalidCharacter,
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NotImplemented,
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};
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pub const Jump = struct {
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label_index: usize,
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code_offset: usize,
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};
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pub const Label = struct {
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code_offset: usize,
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};
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pub const Chunk = struct {
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name: [:0]const u8,
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arity: usize,
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locals_count: usize,
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const_pool: std.ArrayListUnmanaged(*Story.Object),
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bytes: std.ArrayListUnmanaged(u8),
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pub fn finalize(chunk: *Chunk, scope: *Scope) !*Story.Object.ContentPath {
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const gpa = scope.global.gpa;
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const story = scope.global.story;
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try scope.backpatch();
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const const_pool = try chunk.const_pool.toOwnedSlice(gpa);
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const bytes = try chunk.bytes.toOwnedSlice(gpa);
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const knot_name = try Story.Object.String.create(story, chunk.name);
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const content_path = try Story.Object.ContentPath.create(
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story,
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knot_name,
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chunk.arity,
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chunk.locals_count,
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const_pool,
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bytes,
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);
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return content_path;
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}
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pub fn deinit(chunk: *Chunk, gpa: std.mem.Allocator) void {
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chunk.const_pool.deinit(gpa);
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chunk.bytes.deinit(gpa);
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chunk.* = undefined;
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}
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};
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pub const Scope = struct {
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const Scope = struct {
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parent: ?*Scope,
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global: *AstGen,
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chunk: *Chunk,
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@ -122,7 +70,11 @@ pub const Scope = struct {
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return null;
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}
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pub fn insertIdentifier(scope: *Scope, node: *const Ast.Node, symbol: Symbol) !void {
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pub fn insertIdentifier(
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scope: *Scope,
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node: *const Ast.Node,
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symbol: Symbol,
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) error{OutOfMemory}!void {
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const gpa = scope.global.gpa;
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const symbol_table = &scope.symbol_table;
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const token_bytes = scope.global.getLexemeFromNode(node);
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@ -144,27 +96,7 @@ pub const Scope = struct {
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};
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}
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pub fn makeLabel(scope: *Scope) !usize {
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const gpa = scope.global.gpa;
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const label_stack = &scope.global.label_stack;
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const label_id = label_stack.items.len;
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const label_data: Label = .{ .code_offset = 0xffffffff };
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try label_stack.append(gpa, label_data);
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return label_id;
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}
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pub fn setLabel(scope: *Scope, label_id: usize) void {
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const chunk = scope.chunk;
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const code_offset = chunk.bytes.items.len;
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const label_stack = &scope.global.label_stack;
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assert(label_id <= label_stack.items.len);
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const label_data = &label_stack.items[label_id];
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label_data.code_offset = code_offset;
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}
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pub fn makeConstant(scope: *Scope, object: *Story.Object) !usize {
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pub fn makeConstant(scope: *Scope, object: *Story.Object) error{OutOfMemory}!usize {
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const gpa = scope.global.gpa;
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const chunk = scope.chunk;
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const const_id = chunk.const_pool.items.len;
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@ -178,7 +110,7 @@ pub const Scope = struct {
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len: u32,
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};
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pub fn makeString(scope: *Scope, bytes: []const u8) !IndexSlice {
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pub fn makeString(scope: *Scope, bytes: []const u8) error{OutOfMemory}!IndexSlice {
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const global = scope.global;
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const gpa = scope.global.gpa;
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const str_index: u32 = @intCast(global.string_bytes.items.len);
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@ -201,7 +133,11 @@ pub const Scope = struct {
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}
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}
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pub fn makeGlobal(scope: *Scope, node: *const Ast.Node, symbol: Symbol) !void {
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pub fn makeGlobal(
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scope: *Scope,
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node: *const Ast.Node,
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symbol: Symbol,
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) error{OutOfMemory}!void {
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const gpa = scope.global.gpa;
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const global_data = scope.global;
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const token_bytes = global_data.getLexemeFromNode(node);
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@ -209,11 +145,11 @@ pub const Scope = struct {
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return scope.insertIdentifier(node, symbol);
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}
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pub fn emitByte(scope: *Scope, byte: u8) !void {
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pub fn emitByte(scope: *Scope, byte: u8) error{OutOfMemory}!void {
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return scope.chunk.bytes.append(scope.global.gpa, byte);
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}
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pub fn emitSimpleInst(scope: *Scope, op: Story.Opcode) !void {
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pub fn emitSimpleInst(scope: *Scope, op: Story.Opcode) error{OutOfMemory}!void {
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return scope.emitByte(@intFromEnum(op));
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}
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@ -224,7 +160,7 @@ pub const Scope = struct {
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try scope.emitByte(@intCast(arg));
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}
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pub fn emitJumpInst(scope: *Scope, op: Story.Opcode) !void {
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pub fn emitJumpInst(scope: *Scope, op: Story.Opcode) error{OutOfMemory}!usize {
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const bytes = &scope.chunk.bytes;
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try scope.emitSimpleInst(op);
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try scope.emitByte(0xff);
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@ -232,7 +168,125 @@ pub const Scope = struct {
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return bytes.items.len - 2;
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}
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pub fn backpatch(_: *Scope) !void {}
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// Create a new code label.
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pub fn makeLabel(scope: *Scope) error{OutOfMemory}!usize {
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const gpa = scope.global.gpa;
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const dummy_address = 0xffffffff;
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const label_stack = &scope.global.label_stack;
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const label_index = label_stack.items.len;
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const label_data: Label = .{ .code_offset = dummy_address };
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try label_stack.append(gpa, label_data);
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return label_index;
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}
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// Sets the code offset pointed to by a label.
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pub fn setLabel(scope: *Scope, label_id: usize) void {
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const chunk = scope.chunk;
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const code_offset = chunk.bytes.items.len;
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const label_stack = &scope.global.label_stack;
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assert(label_id <= label_stack.items.len);
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const label_data = &label_stack.items[label_id];
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label_data.code_offset = code_offset;
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}
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pub fn makeJump(scope: *Scope, jump: Jump) !usize {
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const gpa = scope.global.gpa;
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const jump_stack = &scope.global.jump_stack;
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const jump_index = jump_stack.items.len;
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try jump_stack.append(gpa, jump);
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return jump_index;
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}
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pub fn resolveLabels(scope: *Scope, start_index: usize, end_index: usize) !void {
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assert(start_index <= end_index);
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const jump_stack = &scope.global.jump_stack;
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const label_stack = &scope.global.label_stack;
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const chunk_bytes = &scope.chunk.bytes;
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const jump_list = jump_stack.items[start_index..end_index];
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for (jump_list) |jump| {
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const label = label_stack.items[jump.label_index];
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const jump_offset: usize = switch (jump.mode) {
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.relative => label.code_offset - jump.code_offset - 2,
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.absolute => label.code_offset,
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};
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if (jump_offset >= std.math.maxInt(u16)) {
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std.debug.print("Too much code to jump over!\n", .{});
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return error.CompilerBug;
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}
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assert(chunk_bytes.capacity >= jump.code_offset + 2);
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chunk_bytes.items[jump.code_offset] = @intCast((jump_offset >> 8) & 0xff);
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chunk_bytes.items[jump.code_offset + 1] = @intCast(jump_offset & 0xff);
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}
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}
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};
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pub const Symbol = union(enum) {
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global_variable: struct {
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is_constant: bool,
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constant_slot: usize,
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node: *const Ast.Node,
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},
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local_variable: struct {
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stack_slot: usize,
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node: *const Ast.Node,
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},
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parameter: struct {
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constant_slot: usize,
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stack_slot: usize,
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},
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};
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pub const Jump = struct {
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mode: enum {
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relative,
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absolute,
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},
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label_index: usize,
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code_offset: usize,
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};
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pub const Label = struct {
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code_offset: usize,
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};
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// Code chunk to emitting bytes and constants to during code generation.
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pub const Chunk = struct {
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name: [:0]const u8,
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arity: usize,
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locals_count: usize,
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const_pool: std.ArrayListUnmanaged(*Story.Object),
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bytes: std.ArrayListUnmanaged(u8),
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pub fn finalize(chunk: *Chunk, scope: *Scope) !*Story.Object.ContentPath {
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const gpa = scope.global.gpa;
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const story = scope.global.story;
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const jump_stack_top = scope.global.jump_stack.items.len;
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try scope.resolveLabels(scope.jump_stack_top, jump_stack_top);
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const const_pool = try chunk.const_pool.toOwnedSlice(gpa);
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const bytes = try chunk.bytes.toOwnedSlice(gpa);
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const knot_name = try Story.Object.String.create(story, chunk.name);
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const content_path = try Story.Object.ContentPath.create(
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story,
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knot_name,
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chunk.arity,
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chunk.locals_count,
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const_pool,
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bytes,
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);
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return content_path;
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}
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pub fn deinit(chunk: *Chunk, gpa: std.mem.Allocator) void {
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chunk.const_pool.deinit(gpa);
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chunk.bytes.deinit(gpa);
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chunk.* = undefined;
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}
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};
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pub fn deinit(astgen: *AstGen) void {
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@ -363,11 +417,11 @@ fn checkContentExpr(scope: *Scope, expr: *const Ast.Node) CheckError!void {
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switch (child_node.tag) {
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.string_literal => {
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try checkStringLiteral(scope, child_node);
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try scope.emitSimpleInst(.content);
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try scope.emitSimpleInst(.stream_push);
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},
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.inline_logic_expr => {
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try checkInlineLogicExpr(scope, child_node);
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try scope.emitSimpleInst(.content);
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try scope.emitSimpleInst(.stream_push);
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},
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else => return error.NotImplemented,
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}
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@ -379,13 +433,6 @@ fn checkContentStmt(scope: *Scope, stmt: *const Ast.Node) CheckError!void {
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return checkContentExpr(scope, expr_node);
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}
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fn checkBlockStmt(parent_scope: *Scope, block_stmt: *const Ast.Node) CheckError!void {
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var block_scope = parent_scope.makeSubBlock();
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defer block_scope.deinit();
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const children = block_stmt.data.list.items orelse return;
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for (children) |child_stmt| try checkStmt(&block_scope, child_stmt);
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}
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fn checkAssignStmt(scope: *Scope, stmt: *const Ast.Node) CheckError!void {
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const lhs = stmt.data.bin.lhs orelse return error.CompilerBug;
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const rhs = stmt.data.bin.rhs orelse return error.CompilerBug;
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@ -413,9 +460,91 @@ fn checkAssignStmt(scope: *Scope, stmt: *const Ast.Node) CheckError!void {
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return scope.fail(.unknown_identifier, lhs);
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}
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fn checkBlockStmt(parent_scope: *Scope, block_stmt: *const Ast.Node) CheckError!void {
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var block_scope = parent_scope.makeSubBlock();
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defer block_scope.deinit();
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const children = block_stmt.data.list.items orelse return;
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for (children) |child_stmt| try checkStmt(&block_scope, child_stmt);
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}
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fn checkChoiceStmt(scope: *Scope, stmt_node: *const Ast.Node) CheckError!void {
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const Choice = struct {
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label_index: usize,
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start_expression: ?*const Ast.Node,
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option_expression: ?*const Ast.Node,
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inner_expression: ?*const Ast.Node,
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block_stmt: ?*const Ast.Node,
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};
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const branch_list = stmt_node.data.list.items orelse unreachable;
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assert(branch_list.len != 0);
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const gpa = scope.global.gpa;
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var choice_list: std.ArrayListUnmanaged(Choice) = .empty;
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defer choice_list.deinit(gpa);
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try choice_list.ensureUnusedCapacity(gpa, branch_list.len);
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for (branch_list) |branch_stmt| {
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assert(branch_stmt.tag == .choice_star_stmt or branch_stmt.tag == .choice_plus_stmt);
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const branch_data = branch_stmt.data.bin;
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const branch_expr = branch_data.lhs orelse unreachable;
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const branch_expr_data = branch_expr.data.choice_expr;
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const label_index = try scope.makeLabel();
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if (branch_expr_data.start_expr) |node| {
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try checkStringLiteral(scope, node);
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try scope.emitSimpleInst(.stream_push);
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}
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if (branch_expr_data.option_expr) |node| {
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try checkStringLiteral(scope, node);
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try scope.emitSimpleInst(.stream_push);
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}
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const jump_offset = try scope.emitJumpInst(.br_push);
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_ = try scope.makeJump(.{
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.mode = .absolute,
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.label_index = label_index,
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.code_offset = jump_offset,
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});
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choice_list.appendAssumeCapacity(.{
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.label_index = label_index,
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.start_expression = branch_expr_data.start_expr,
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.inner_expression = branch_expr_data.inner_expr,
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.option_expression = branch_expr_data.option_expr,
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.block_stmt = branch_data.rhs,
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});
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}
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try scope.emitSimpleInst(.br_table);
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try scope.emitSimpleInst(.br_select_index);
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try scope.emitSimpleInst(.br_dispatch);
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for (choice_list.items) |choice| {
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scope.setLabel(choice.label_index);
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if (choice.start_expression) |expr_node| {
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try checkStringLiteral(scope, expr_node);
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try scope.emitSimpleInst(.stream_push);
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}
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if (choice.inner_expression) |expr_node| {
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try checkStringLiteral(scope, expr_node);
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try scope.emitSimpleInst(.stream_push);
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}
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try scope.emitSimpleInst(.stream_flush);
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if (choice.block_stmt) |block| {
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try checkBlockStmt(scope, block);
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} else {
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try scope.emitSimpleInst(.exit);
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}
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}
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}
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fn checkVarDecl(scope: *Scope, decl_node: *const Ast.Node) !void {
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const identifier_node = decl_node.data.bin.lhs orelse return error.Fucked;
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const expr_node = decl_node.data.bin.rhs orelse return error.Fucked;
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const identifier_node = decl_node.data.bin.lhs orelse return error.CompilerBug;
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const expr_node = decl_node.data.bin.rhs orelse return error.CompilerBug;
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try checkExpr(scope, expr_node);
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switch (decl_node.tag) {
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@ -461,6 +590,7 @@ fn checkStmt(scope: *Scope, stmt: *const Ast.Node) CheckError!void {
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.temp_decl => try checkVarDecl(scope, stmt),
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.assign_stmt => try checkAssignStmt(scope, stmt),
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.content_stmt => try checkContentStmt(scope, stmt),
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.choice_stmt => try checkChoiceStmt(scope, stmt),
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.expr_stmt => try checkExprStmt(scope, stmt),
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else => return error.NotImplemented,
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}
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@ -522,23 +652,18 @@ fn dumpStringsWithHex(astgen: *const AstGen) void {
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std.debug.print("[{d:04}] ", .{start});
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for (s) |b| std.debug.print("{x:02} ", .{b});
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std.debug.print("00 {s}\n", .{s});
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std.debug.print("00: {s}\n", .{s});
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start = end + 1;
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}
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}
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/// Perform code generation via tree-walk.
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pub fn generate(gpa: std.mem.Allocator, tree: *const Ast) !Story {
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const root_node = tree.root orelse return error.Fucked;
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const root_node = tree.root orelse return error.CompilerBug;
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var story: Story = .{
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.allocator = gpa,
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.is_exited = false,
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.can_advance = false,
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.gc_objects = .{},
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.globals = .empty,
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.paths = .empty,
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.stack = .empty,
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.call_stack = .empty,
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};
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var astgen: AstGen = .{
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.gpa = gpa,
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