Commit 75efb736ce704fc43bdbe2410989c2b275d855e6 | zig

author	Andrew Kelley <andrew@ziglang.org> 2023-11-04 17:38:10-07:00
committer	Andrew Kelley <andrew@ziglang.org> 2023-11-04 17:38:10-07:00
log	75efb736ce704fc43bdbe2410989c2b275d855e6
tree	9601aa3c7293a4791f0451a9a99a2319876e2fb0
parent	31ad3af956231357ffa2c0fcfaf96a95c2fe1e8b

zig reduce: run results through astgen

and use that to fix up usused variable declarations and parameters that
are caused by transformations.

also add a transformation to replace global variable init with
`undefined`.

2 files changed, 59 insertions(+), 6 deletions(-)

src
- reduce.zig
- reduce
  - Walk.zig

src/reduce.zig+53-3

...	...	@@ -5,6 +5,8 @@ const assert = std.debug.assert;
5	5	const fatal = @import("./main.zig").fatal;
6	6	const Ast = std.zig.Ast;
7	7	const Walk = @import("reduce/Walk.zig");
	8	const AstGen = @import("AstGen.zig");
	9	const Zir = @import("Zir.zig");
8	10
9	11	const usage =
10	12	\\zig reduce [options] ./checker root_source_file.zig [-- [argv]]
...	...	@@ -39,8 +41,6 @@ const Interestingness = enum { interesting, unknown, boring };
39	41	// - add support for parsing the module flags
40	42	// - more fancy transformations
41	43	// - @import inlining of modules
42		// - @import inlining of files
43		// - deleting unused functions and other globals
44	44	// - removing statements or blocks of code
45	45	// - replacing operands of `and` and `or` with `true` and `false`
46	46	// - replacing if conditions with `true` and `false`
...	...	@@ -109,6 +109,9 @@ pub fn main(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
109	109	var rendered = std.ArrayList(u8).init(gpa);
110	110	defer rendered.deinit();
111	111
	112	var astgen_input = std.ArrayList(u8).init(gpa);
	113	defer astgen_input.deinit();
	114
112	115	var tree = try parse(gpa, root_source_file_path);
113	116	defer {
114	117	gpa.free(tree.source);
...	...	@@ -129,6 +132,10 @@ pub fn main(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
129	132
130	133	var fixups: Ast.Fixups = .{};
131	134	defer fixups.deinit(gpa);
	135
	136	var more_fixups: Ast.Fixups = .{};
	137	defer more_fixups.deinit(gpa);
	138
132	139	var rng = std.rand.DefaultPrng.init(seed);
133	140
134	141	// 1. Walk the AST of the source file looking for independent
...	...	@@ -171,8 +178,51 @@ pub fn main(gpa: Allocator, arena: Allocator, args: []const []const u8) !void {
171	178
172	179	rendered.clearRetainingCapacity();
173	180	try tree.renderToArrayList(&rendered, fixups);
174		try std.fs.cwd().writeFile(root_source_file_path, rendered.items);
175	181
	182	// The transformations we applied may have resulted in unused locals,
	183	// in which case we would like to add the respective discards.
	184	{
	185	try astgen_input.resize(rendered.items.len);
	186	@memcpy(astgen_input.items, rendered.items);
	187	try astgen_input.append(0);
	188	const source_with_null = astgen_input.items[0 .. astgen_input.items.len - 1 :0];
	189	var astgen_tree = try Ast.parse(gpa, source_with_null, .zig);
	190	defer astgen_tree.deinit(gpa);
	191	if (astgen_tree.errors.len != 0) {
	192	@panic("syntax errors occurred");
	193	}
	194	var zir = try AstGen.generate(gpa, astgen_tree);
	195	defer zir.deinit(gpa);
	196
	197	if (zir.hasCompileErrors()) {
	198	more_fixups.clearRetainingCapacity();
	199	const payload_index = zir.extra[@intFromEnum(Zir.ExtraIndex.compile_errors)];
	200	assert(payload_index != 0);
	201	const header = zir.extraData(Zir.Inst.CompileErrors, payload_index);
	202	var extra_index = header.end;
	203	for (0..header.data.items_len) \|_\| {
	204	const item = zir.extraData(Zir.Inst.CompileErrors.Item, extra_index);
	205	extra_index = item.end;
	206	const msg = zir.nullTerminatedString(item.data.msg);
	207	if (mem.eql(u8, msg, "unused local constant") or
	208	mem.eql(u8, msg, "unused local variable") or
	209	mem.eql(u8, msg, "unused function parameter") or
	210	mem.eql(u8, msg, "unused capture"))
	211	{
	212	const ident_token = item.data.token;
	213	try more_fixups.unused_var_decls.put(gpa, ident_token, {});
	214	} else {
	215	std.debug.print("found other ZIR error: '{s}'\n", .{msg});
	216	}
	217	}
	218	if (more_fixups.count() != 0) {
	219	rendered.clearRetainingCapacity();
	220	try astgen_tree.renderToArrayList(&rendered, more_fixups);
	221	}
	222	}
	223	}
	224
	225	try std.fs.cwd().writeFile(root_source_file_path, rendered.items);
176	226	//std.debug.print("trying this code:\n{s}\n", .{rendered.items});
177	227
178	228	const interestingness = try runCheck(arena, interestingness_argv.items);

src/reduce/Walk.zig+6-3

...	...	@@ -581,9 +581,12 @@ fn walkGlobalVarDecl(w: *Walk, decl_node: Ast.Node.Index, var_decl: Ast.full.Var
581	581	try walkExpression(w, var_decl.ast.section_node);
582	582	}
583	583
584		assert(var_decl.ast.init_node != 0);
585
586		return walkExpression(w, var_decl.ast.init_node);
	584	if (var_decl.ast.init_node != 0) {
	585	if (!isUndefinedIdent(w.ast, var_decl.ast.init_node)) {
	586	try w.transformations.append(.{ .replace_with_undef = var_decl.ast.init_node });
	587	}
	588	try walkExpression(w, var_decl.ast.init_node);
	589	}
587	590	}
588	591
589	592	fn walkLocalVarDecl(w: *Walk, var_decl: Ast.full.VarDecl) Error!void {