Commit dadc4327e109e1cb13ae7e6132db586f5f849396 | zig

author	Andrew Kelley <andrew@ziglang.org> 2020-05-28 22:45:59-04:00
committer	Andrew Kelley <andrew@ziglang.org> 2020-05-28 22:45:59-04:00
log	dadc4327e109e1cb13ae7e6132db586f5f849396
tree	b83c3d6b74fe3f299de9a1869e4b64e614d2fa5e
parent	2ae9e06363b294f60b62e765d31fce4417e14a9d
parent	5d77fede896ff7446e9946f91c74b7632b63253e

Merge branch 'stage2-vaddr-alloc'

6 files changed, 810 insertions(+), 271 deletions(-)

src-self-hosted
test
- stage2
  - zir.zig

src-self-hosted/Module.zig+367-113

...	...	@@ -55,9 +55,20 @@ failed_files: std.AutoHashMap(Scope.ZIRModule, ErrorMsg),
55	55	/// The ErrorMsg memory is owned by the `Export`, using Module's allocator.
56	56	failed_exports: std.AutoHashMap(Export, ErrorMsg),
57	57
	58	/// Incrementing integer used to compare against the corresponding Decl
	59	/// field to determine whether a Decl's status applies to an ongoing update, or a
	60	/// previous analysis.
	61	generation: u32 = 0,
	62
	63	/// Candidates for deletion. After a semantic analysis update completes, this list
	64	/// contains Decls that need to be deleted if they end up having no references to them.
	65	deletion_set: std.ArrayListUnmanaged(Decl) = std.ArrayListUnmanaged(Decl){},
	66
58	67	pub const WorkItem = union(enum) {
59	68	/// Write the machine code for a Decl to the output file.
60	69	codegen_decl: *Decl,
	70	/// Decl has been determined to be outdated; perform semantic analysis again.
	71	re_analyze_decl: *Decl,
61	72	};
62	73
63	74	pub const Export = struct {
...	...	@@ -68,6 +79,8 @@ pub const Export = struct {
68	79	link: link.ElfFile.Export,
69	80	/// The Decl that performs the export. Note that this is not the Decl being exported.
70	81	owner_decl: *Decl,
	82	/// The Decl being exported. Note this is not the Decl performing the export.
	83	exported_decl: *Decl,
71	84	status: enum {
72	85	in_progress,
73	86	failed,
...	...	@@ -94,8 +107,7 @@ pub const Decl = struct {
94	107	/// This is the base offset that src offsets within this Decl are relative to.
95	108	src: usize,
96	109	/// The most recent value of the Decl after a successful semantic analysis.
97		/// The tag for this union is determined by the tag value of the analysis field.
98		typed_value: union {
	110	typed_value: union(enum) {
99	111	never_succeeded: void,
100	112	most_recent: TypedValue.Managed,
101	113	},
...	...	@@ -104,50 +116,56 @@ pub const Decl = struct {
104	116	/// analysis of the function body is performed with this value set to `success`. Functions
105	117	/// have their own analysis status field.
106	118	analysis: enum {
107		initial_in_progress,
	119	/// Semantic analysis for this Decl is running right now. This state detects dependency loops.
	120	in_progress,
108	121	/// This Decl might be OK but it depends on another one which did not successfully complete
109		/// semantic analysis. This Decl never had a value computed.
110		initial_dependency_failure,
111		/// Semantic analysis failure. This Decl never had a value computed.
	122	/// semantic analysis.
	123	dependency_failure,
	124	/// Semantic analysis failure.
112	125	/// There will be a corresponding ErrorMsg in Module.failed_decls.
113		initial_sema_failure,
114		/// In this case the `typed_value.most_recent` can still be accessed.
	126	sema_failure,
115	127	/// There will be a corresponding ErrorMsg in Module.failed_decls.
116	128	codegen_failure,
117		/// In this case the `typed_value.most_recent` can still be accessed.
118	129	/// There will be a corresponding ErrorMsg in Module.failed_decls.
119	130	/// This indicates the failure was something like running out of disk space,
120	131	/// and attempting codegen again may succeed.
121	132	codegen_failure_retryable,
122		/// This Decl might be OK but it depends on another one which did not successfully complete
123		/// semantic analysis. There is a most recent value available.
124		repeat_dependency_failure,
125		/// Semantic anlaysis failure, but the `typed_value.most_recent` can be accessed.
126		/// There will be a corresponding ErrorMsg in Module.failed_decls.
127		repeat_sema_failure,
128		/// Completed successfully before; the `typed_value.most_recent` can be accessed, and
129		/// new semantic analysis is in progress.
130		repeat_in_progress,
131		/// Everything is done and updated.
	133	/// Everything is done. During an update, this Decl may be out of date, depending
	134	/// on its dependencies. The `generation` field can be used to determine if this
	135	/// completion status occurred before or after a given update.
132	136	complete,
	137	/// A Module update is in progress, and this Decl has been flagged as being known
	138	/// to require re-analysis.
	139	outdated,
133	140	},
	141	/// This flag is set when this Decl is added to a check_for_deletion set, and cleared
	142	/// when removed.
	143	deletion_flag: bool,
	144	/// An integer that can be checked against the corresponding incrementing
	145	/// generation field of Module. This is used to determine whether `complete` status
	146	/// represents pre- or post- re-analysis.
	147	generation: u32,
134	148
135	149	/// Represents the position of the code in the output file.
136	150	/// This is populated regardless of semantic analysis and code generation.
137		link: link.ElfFile.Decl = link.ElfFile.Decl.empty,
	151	link: link.ElfFile.TextBlock = link.ElfFile.TextBlock.empty,
	152
	153	contents_hash: Hash,
138	154
139	155	/// The shallow set of other decls whose typed_value could possibly change if this Decl's
140	156	/// typed_value is modified.
141		/// TODO look into using a lightweight map/set data structure rather than a linear array.
142	157	dependants: ArrayListUnmanaged(Decl) = ArrayListUnmanaged(Decl){},
143
144		contents_hash: Hash,
	158	/// The shallow set of other decls whose typed_value changing indicates that this Decl's
	159	/// typed_value may need to be regenerated.
	160	dependencies: ArrayListUnmanaged(Decl) = ArrayListUnmanaged(Decl){},
145	161
146	162	pub fn destroy(self: Decl, allocator: Allocator) void {
147	163	allocator.free(mem.spanZ(self.name));
148	164	if (self.typedValueManaged()) \|tvm\| {
149	165	tvm.deinit(allocator);
150	166	}
	167	self.dependants.deinit(allocator);
	168	self.dependencies.deinit(allocator);
151	169	allocator.destroy(self);
152	170	}
153	171
...	...	@@ -172,7 +190,7 @@ pub const Decl = struct {
172	190	pub fn fullyQualifiedNameHash(self: Decl) Hash {
173	191	// Right now we only have ZIRModule as the source. So this is simply the
174	192	// relative name of the decl.
175		return hashSimpleName(mem.spanZ(u8, self.name));
	193	return hashSimpleName(mem.spanZ(self.name));
176	194	}
177	195
178	196	pub fn typedValue(self: *Decl) error{AnalysisFail}!TypedValue {
...	...	@@ -200,20 +218,31 @@ pub const Decl = struct {
200	218	}
201	219
202	220	fn typedValueManaged(self: Decl) ?TypedValue.Managed {
203		switch (self.analysis) {
204		.initial_in_progress,
205		.initial_dependency_failure,
206		.initial_sema_failure,
207		=> return null,
208		.codegen_failure,
209		.codegen_failure_retryable,
210		.repeat_dependency_failure,
211		.repeat_sema_failure,
212		.repeat_in_progress,
213		.complete,
214		=> return &self.typed_value.most_recent,
	221	switch (self.typed_value) {
	222	.most_recent => \|*x\| return x,
	223	.never_succeeded => return null,
215	224	}
216	225	}
	226
	227	fn removeDependant(self: Decl, other: Decl) void {
	228	for (self.dependants.items) \|item, i\| {
	229	if (item == other) {
	230	_ = self.dependants.swapRemove(i);
	231	return;
	232	}
	233	}
	234	unreachable;
	235	}
	236
	237	fn removeDependency(self: Decl, other: Decl) void {
	238	for (self.dependencies.items) \|item, i\| {
	239	if (item == other) {
	240	_ = self.dependencies.swapRemove(i);
	241	return;
	242	}
	243	}
	244	unreachable;
	245	}
217	246	};
218	247
219	248	/// Fn struct memory is owned by the Decl's TypedValue.Managed arena allocator.
...	...	@@ -266,12 +295,12 @@ pub const Scope = struct {
266	295
267	296	/// Asserts the scope has a parent which is a DeclAnalysis and
268	297	/// returns the Decl.
269		pub fn decl(self: Scope) Decl {
270		switch (self.tag) {
271		.block => return self.cast(Block).?.decl,
272		.decl => return self.cast(DeclAnalysis).?.decl,
273		.zir_module => unreachable,
274		}
	298	pub fn decl(self: Scope) ?Decl {
	299	return switch (self.tag) {
	300	.block => self.cast(Block).?.decl,
	301	.decl => self.cast(DeclAnalysis).?.decl,
	302	.zir_module => null,
	303	};
275	304	}
276	305
277	306	/// Asserts the scope has a parent which is a ZIRModule and
...	...	@@ -477,6 +506,7 @@ pub fn init(gpa: *Allocator, options: InitOptions) !Module {
477	506	pub fn deinit(self: *Module) void {
478	507	self.bin_file.deinit();
479	508	const allocator = self.allocator;
	509	self.deletion_set.deinit(allocator);
480	510	self.work_queue.deinit();
481	511	{
482	512	var it = self.decl_table.iterator();
...	...	@@ -517,11 +547,7 @@ pub fn deinit(self: *Module) void {
517	547	{
518	548	var it = self.export_owners.iterator();
519	549	while (it.next()) \|kv\| {
520		const export_list = kv.value;
521		for (export_list) \|exp\| {
522		allocator.destroy(exp);
523		}
524		allocator.free(export_list);
	550	freeExportList(allocator, kv.value);
525	551	}
526	552	self.export_owners.deinit();
527	553	}
...	...	@@ -532,12 +558,21 @@ pub fn deinit(self: *Module) void {
532	558	self.* = undefined;
533	559	}
534	560
	561	fn freeExportList(allocator: Allocator, export_list: []Export) void {
	562	for (export_list) \|exp\| {
	563	allocator.destroy(exp);
	564	}
	565	allocator.free(export_list);
	566	}
	567
535	568	pub fn target(self: Module) std.Target {
536	569	return self.bin_file.options.target;
537	570	}
538	571
539	572	/// Detect changes to source files, perform semantic analysis, and update the output files.
540	573	pub fn update(self: *Module) !void {
	574	self.generation += 1;
	575
541	576	// TODO Use the cache hash file system to detect which source files changed.
542	577	// Here we simulate a full cache miss.
543	578	// Analyze the root source file now.
...	...	@@ -550,6 +585,15 @@ pub fn update(self: *Module) !void {
550	585
551	586	try self.performAllTheWork();
552	587
	588	// Process the deletion set.
	589	while (self.deletion_set.popOrNull()) \|decl\| {
	590	if (decl.dependants.items.len != 0) {
	591	decl.deletion_flag = false;
	592	continue;
	593	}
	594	try self.deleteDecl(decl);
	595	}
	596
553	597	// Unload all the source files from memory.
554	598	self.root_scope.unload(self.allocator);
555	599
...	...	@@ -634,15 +678,12 @@ const InnerError = error{ OutOfMemory, AnalysisFail };
634	678	pub fn performAllTheWork(self: *Module) error{OutOfMemory}!void {
635	679	while (self.work_queue.readItem()) \|work_item\| switch (work_item) {
636	680	.codegen_decl => \|decl\| switch (decl.analysis) {
637		.initial_in_progress,
638		.repeat_in_progress,
639		=> unreachable,
	681	.in_progress => unreachable,
	682	.outdated => unreachable,
640	683
641		.initial_sema_failure,
642		.repeat_sema_failure,
	684	.sema_failure,
643	685	.codegen_failure,
644		.initial_dependency_failure,
645		.repeat_dependency_failure,
	686	.dependency_failure,
646	687	=> continue,
647	688
648	689	.complete, .codegen_failure_retryable => {
...	...	@@ -668,7 +709,7 @@ pub fn performAllTheWork(self: *Module) error{OutOfMemory}!void {
668	709	self.bin_file.updateDecl(self, decl) catch \|err\| switch (err) {
669	710	error.OutOfMemory => return error.OutOfMemory,
670	711	error.AnalysisFail => {
671		decl.analysis = .repeat_dependency_failure;
	712	decl.analysis = .dependency_failure;
672	713	},
673	714	else => {
674	715	try self.failed_decls.ensureCapacity(self.failed_decls.size + 1);
...	...	@@ -683,9 +724,60 @@ pub fn performAllTheWork(self: *Module) error{OutOfMemory}!void {
683	724	};
684	725	},
685	726	},
	727	.re_analyze_decl => \|decl\| switch (decl.analysis) {
	728	.in_progress => unreachable,
	729
	730	.sema_failure,
	731	.codegen_failure,
	732	.dependency_failure,
	733	.complete,
	734	.codegen_failure_retryable,
	735	=> continue,
	736
	737	.outdated => {
	738	const zir_module = self.getSrcModule(decl.scope) catch \|err\| switch (err) {
	739	error.OutOfMemory => return error.OutOfMemory,
	740	else => {
	741	try self.failed_decls.ensureCapacity(self.failed_decls.size + 1);
	742	self.failed_decls.putAssumeCapacityNoClobber(decl, try ErrorMsg.create(
	743	self.allocator,
	744	decl.src,
	745	"unable to load source file '{}': {}",
	746	.{decl.scope.sub_file_path, @errorName(err)},
	747	));
	748	decl.analysis = .codegen_failure_retryable;
	749	continue;
	750	},
	751	};
	752	const decl_name = mem.spanZ(decl.name);
	753	// We already detected deletions, so we know this will be found.
	754	const src_decl = zir_module.findDecl(decl_name).?;
	755	self.reAnalyzeDecl(decl, src_decl) catch \|err\| switch (err) {
	756	error.OutOfMemory => return error.OutOfMemory,
	757	error.AnalysisFail => continue,
	758	};
	759	}
	760	},
686	761	};
687	762	}
688	763
	764	fn declareDeclDependency(self: Module, depender: Decl, dependee: *Decl) !void {
	765	try depender.dependencies.ensureCapacity(self.allocator, depender.dependencies.items.len + 1);
	766	try dependee.dependants.ensureCapacity(self.allocator, dependee.dependants.items.len + 1);
	767
	768	for (depender.dependencies.items) \|item\| {
	769	if (item == dependee) break; // Already in the set.
	770	} else {
	771	depender.dependencies.appendAssumeCapacity(dependee);
	772	}
	773
	774	for (dependee.dependants.items) \|item\| {
	775	if (item == depender) break; // Already in the set.
	776	} else {
	777	dependee.dependants.appendAssumeCapacity(depender);
	778	}
	779	}
	780
689	781	fn getSource(self: Module, root_scope: Scope.ZIRModule) ![:0]const u8 {
690	782	switch (root_scope.source) {
691	783	.unloaded => {
...	...	@@ -742,13 +834,6 @@ fn getSrcModule(self: Module, root_scope: Scope.ZIRModule) !*zir.Module {
742	834	}
743	835
744	836	fn analyzeRoot(self: Module, root_scope: Scope.ZIRModule) !void {
745		// TODO use the cache to identify, from the modified source files, the decls which have
746		// changed based on the span of memory that represents the decl in the re-parsed source file.
747		// Use the cached dependency graph to recursively determine the set of decls which need
748		// regeneration.
749		// Here we simulate adding a source file which was previously not part of the compilation,
750		// which means scanning the decls looking for exports.
751		// TODO also identify decls that need to be deleted.
752	837	switch (root_scope.status) {
753	838	.never_loaded => {
754	839	const src_module = try self.getSrcModule(root_scope);
...	...	@@ -759,7 +844,7 @@ fn analyzeRoot(self: Module, root_scope: Scope.ZIRModule) !void {
759	844
760	845	for (src_module.decls) \|decl\| {
761	846	if (decl.cast(zir.Inst.Export)) \|export_inst\| {
762		_ = try self.resolveDecl(&root_scope.base, &export_inst.base, link.ElfFile.Decl.empty);
	847	_ = try self.resolveDecl(&root_scope.base, &export_inst.base);
763	848	}
764	849	}
765	850	},
...	...	@@ -772,41 +857,112 @@ fn analyzeRoot(self: Module, root_scope: Scope.ZIRModule) !void {
772	857	=> {
773	858	const src_module = try self.getSrcModule(root_scope);
774	859
775		// Look for changed decls.
	860	var exports_to_resolve = std.ArrayList(*zir.Inst).init(self.allocator);
	861	defer exports_to_resolve.deinit();
	862
	863	// Keep track of the decls that we expect to see in this file so that
	864	// we know which ones have been deleted.
	865	var deleted_decls = std.AutoHashMap(*Decl, void).init(self.allocator);
	866	defer deleted_decls.deinit();
	867	try deleted_decls.ensureCapacity(self.decl_table.size);
	868	{
	869	var it = self.decl_table.iterator();
	870	while (it.next()) \|kv\| {
	871	deleted_decls.putAssumeCapacityNoClobber(kv.value, {});
	872	}
	873	}
	874
776	875	for (src_module.decls) \|src_decl\| {
777	876	const name_hash = Decl.hashSimpleName(src_decl.name);
778	877	if (self.decl_table.get(name_hash)) \|kv\| {
779	878	const decl = kv.value;
	879	deleted_decls.removeAssertDiscard(decl);
780	880	const new_contents_hash = Decl.hashSimpleName(src_decl.contents);
781	881	if (!mem.eql(u8, &new_contents_hash, &decl.contents_hash)) {
782		// TODO recursive dependency management
783		//std.debug.warn("noticed that '{}' changed\n", .{src_decl.name});
784		self.decl_table.removeAssertDiscard(name_hash);
785		const saved_link = decl.link;
786		decl.destroy(self.allocator);
787		if (self.export_owners.getValue(decl)) \|exports\| {
788		@panic("TODO handle updating a decl that does an export");
789		}
790		const new_decl = self.resolveDecl(
791		&root_scope.base,
792		src_decl,
793		saved_link,
794		) catch \|err\| switch (err) {
795		error.OutOfMemory => return error.OutOfMemory,
796		error.AnalysisFail => continue,
797		};
798		if (self.decl_exports.remove(decl)) \|entry\| {
799		self.decl_exports.putAssumeCapacityNoClobber(new_decl, entry.value);
800		}
	882	//std.debug.warn("noticed '{}' source changed\n", .{src_decl.name});
	883	decl.analysis = .outdated;
	884	decl.contents_hash = new_contents_hash;
	885	try self.work_queue.writeItem(.{ .re_analyze_decl = decl });
801	886	}
802	887	} else if (src_decl.cast(zir.Inst.Export)) \|export_inst\| {
803		_ = try self.resolveDecl(&root_scope.base, &export_inst.base, link.ElfFile.Decl.empty);
	888	try exports_to_resolve.append(&export_inst.base);
	889	}
	890	}
	891	{
	892	// Handle explicitly deleted decls from the source code. Not to be confused
	893	// with when we delete decls because they are no longer referenced.
	894	var it = deleted_decls.iterator();
	895	while (it.next()) \|kv\| {
	896	//std.debug.warn("noticed '{}' deleted from source\n", .{kv.key.name});
	897	try self.deleteDecl(kv.key);
804	898	}
805	899	}
	900	for (exports_to_resolve.items) \|export_inst\| {
	901	_ = try self.resolveDecl(&root_scope.base, export_inst);
	902	}
806	903	},
807	904	}
808	905	}
809	906
	907	fn deleteDecl(self: Module, decl: Decl) !void {
	908	//std.debug.warn("deleting decl '{}'\n", .{decl.name});
	909	const name_hash = decl.fullyQualifiedNameHash();
	910	self.decl_table.removeAssertDiscard(name_hash);
	911	// Remove itself from its dependencies, because we are about to destroy the decl pointer.
	912	for (decl.dependencies.items) \|dep\| {
	913	dep.removeDependant(decl);
	914	if (dep.dependants.items.len == 0) {
	915	// We don't recursively perform a deletion here, because during the update,
	916	// another reference to it may turn up.
	917	assert(!dep.deletion_flag);
	918	dep.deletion_flag = true;
	919	try self.deletion_set.append(self.allocator, dep);
	920	}
	921	}
	922	// Anything that depends on this deleted decl certainly needs to be re-analyzed.
	923	for (decl.dependants.items) \|dep\| {
	924	dep.removeDependency(decl);
	925	if (dep.analysis != .outdated) {
	926	dep.analysis = .outdated;
	927	try self.work_queue.writeItem(.{ .re_analyze_decl = dep });
	928	}
	929	}
	930	self.deleteDeclExports(decl);
	931	self.bin_file.freeDecl(decl);
	932	decl.destroy(self.allocator);
	933	}
	934
	935	/// Delete all the Export objects that are caused by this Decl. Re-analysis of
	936	/// this Decl will cause them to be re-created (or not).
	937	fn deleteDeclExports(self: Module, decl: Decl) void {
	938	const kv = self.export_owners.remove(decl) orelse return;
	939
	940	for (kv.value) \|exp\| {
	941	if (self.decl_exports.get(exp.exported_decl)) \|decl_exports_kv\| {
	942	// Remove exports with owner_decl matching the regenerating decl.
	943	const list = decl_exports_kv.value;
	944	var i: usize = 0;
	945	var new_len = list.len;
	946	while (i < new_len) {
	947	if (list[i].owner_decl == decl) {
	948	mem.copyBackwards(*Export, list[i..], list[i + 1..new_len]);
	949	new_len -= 1;
	950	} else {
	951	i += 1;
	952	}
	953	}
	954	decl_exports_kv.value = self.allocator.shrink(list, new_len);
	955	if (new_len == 0) {
	956	self.decl_exports.removeAssertDiscard(exp.exported_decl);
	957	}
	958	}
	959
	960	self.bin_file.deleteExport(exp.link);
	961	self.allocator.destroy(exp);
	962	}
	963	self.allocator.free(kv.value);
	964	}
	965
810	966	fn analyzeFnBody(self: Module, decl: Decl, func: *Fn) !void {
811	967	// Use the Decl's arena for function memory.
812	968	var arena = decl.typed_value.most_recent.arena.?.promote(self.allocator);
...	...	@@ -836,15 +992,111 @@ fn analyzeFnBody(self: Module, decl: Decl, func: *Fn) !void {
836	992	};
837	993	}
838	994
839		fn resolveDecl(
840		self: *Module,
841		scope: *Scope,
842		old_inst: *zir.Inst,
843		bin_file_link: link.ElfFile.Decl,
844		) InnerError!*Decl {
	995	fn reAnalyzeDecl(self: Module, decl: Decl, old_inst: *zir.Inst) InnerError!void {
	996	switch (decl.analysis) {
	997	.in_progress => unreachable,
	998	.dependency_failure,
	999	.sema_failure,
	1000	.codegen_failure,
	1001	.codegen_failure_retryable,
	1002	.complete,
	1003	=> return,
	1004
	1005	.outdated => {}, // Decl re-analysis
	1006	}
	1007	//std.debug.warn("re-analyzing {}\n", .{decl.name});
	1008	decl.src = old_inst.src;
	1009
	1010	// The exports this Decl performs will be re-discovered, so we remove them here
	1011	// prior to re-analysis.
	1012	self.deleteDeclExports(decl);
	1013	// Dependencies will be re-discovered, so we remove them here prior to re-analysis.
	1014	for (decl.dependencies.items) \|dep\| {
	1015	dep.removeDependant(decl);
	1016	if (dep.dependants.items.len == 0) {
	1017	// We don't perform a deletion here, because this Decl or another one
	1018	// may end up referencing it before the update is complete.
	1019	assert(!dep.deletion_flag);
	1020	dep.deletion_flag = true;
	1021	try self.deletion_set.append(self.allocator, dep);
	1022	}
	1023	}
	1024	decl.dependencies.shrink(self.allocator, 0);
	1025	var decl_scope: Scope.DeclAnalysis = .{
	1026	.decl = decl,
	1027	.arena = std.heap.ArenaAllocator.init(self.allocator),
	1028	};
	1029	errdefer decl_scope.arena.deinit();
	1030
	1031	const typed_value = self.analyzeInstConst(&decl_scope.base, old_inst) catch \|err\| switch (err) {
	1032	error.OutOfMemory => return error.OutOfMemory,
	1033	error.AnalysisFail => {
	1034	switch (decl.analysis) {
	1035	.in_progress => decl.analysis = .dependency_failure,
	1036	else => {},
	1037	}
	1038	decl.generation = self.generation;
	1039	return error.AnalysisFail;
	1040	},
	1041	};
	1042	const arena_state = try decl_scope.arena.allocator.create(std.heap.ArenaAllocator.State);
	1043	arena_state.* = decl_scope.arena.state;
	1044
	1045	var prev_type_has_bits = false;
	1046	var type_changed = true;
	1047
	1048	if (decl.typedValueManaged()) \|tvm\| {
	1049	prev_type_has_bits = tvm.typed_value.ty.hasCodeGenBits();
	1050	type_changed = !tvm.typed_value.ty.eql(typed_value.ty);
	1051
	1052	tvm.deinit(self.allocator);
	1053	}
	1054	decl.typed_value = .{
	1055	.most_recent = .{
	1056	.typed_value = typed_value,
	1057	.arena = arena_state,
	1058	},
	1059	};
	1060	decl.analysis = .complete;
	1061	decl.generation = self.generation;
	1062	if (typed_value.ty.hasCodeGenBits()) {
	1063	// We don't fully codegen the decl until later, but we do need to reserve a global
	1064	// offset table index for it. This allows us to codegen decls out of dependency order,
	1065	// increasing how many computations can be done in parallel.
	1066	try self.bin_file.allocateDeclIndexes(decl);
	1067	try self.work_queue.writeItem(.{ .codegen_decl = decl });
	1068	} else if (prev_type_has_bits) {
	1069	self.bin_file.freeDecl(decl);
	1070	}
	1071
	1072	// If the decl is a function, and the type is the same, we do not need
	1073	// to chase the dependants.
	1074	if (type_changed or typed_value.val.tag() != .function) {
	1075	for (decl.dependants.items) \|dep\| {
	1076	switch (dep.analysis) {
	1077	.in_progress => unreachable,
	1078	.outdated => continue, // already queued for update
	1079
	1080	.dependency_failure,
	1081	.sema_failure,
	1082	.codegen_failure,
	1083	.codegen_failure_retryable,
	1084	.complete,
	1085	=> if (dep.generation != self.generation) {
	1086	dep.analysis = .outdated;
	1087	try self.work_queue.writeItem(.{ .re_analyze_decl = dep });
	1088	},
	1089	}
	1090	}
	1091	}
	1092	}
	1093
	1094	fn resolveDecl(self: Module, scope: Scope, old_inst: zir.Inst) InnerError!Decl {
845	1095	const hash = Decl.hashSimpleName(old_inst.name);
846	1096	if (self.decl_table.get(hash)) \|kv\| {
847		return kv.value;
	1097	const decl = kv.value;
	1098	try self.reAnalyzeDecl(decl, old_inst);
	1099	return decl;
848	1100	} else {
849	1101	const new_decl = blk: {
850	1102	try self.decl_table.ensureCapacity(self.decl_table.size + 1);
...	...	@@ -857,9 +1109,11 @@ fn resolveDecl(
857	1109	.scope = scope.namespace(),
858	1110	.src = old_inst.src,
859	1111	.typed_value = .{ .never_succeeded = {} },
860		.analysis = .initial_in_progress,
	1112	.analysis = .in_progress,
	1113	.deletion_flag = false,
861	1114	.contents_hash = Decl.hashSimpleName(old_inst.contents),
862		.link = bin_file_link,
	1115	.link = link.ElfFile.TextBlock.empty,
	1116	.generation = 0,
863	1117	};
864	1118	self.decl_table.putAssumeCapacityNoClobber(hash, new_decl);
865	1119	break :blk new_decl;
...	...	@@ -875,10 +1129,10 @@ fn resolveDecl(
875	1129	error.OutOfMemory => return error.OutOfMemory,
876	1130	error.AnalysisFail => {
877	1131	switch (new_decl.analysis) {
878		.initial_in_progress => new_decl.analysis = .initial_dependency_failure,
879		.repeat_in_progress => new_decl.analysis = .repeat_dependency_failure,
	1132	.in_progress => new_decl.analysis = .dependency_failure,
880	1133	else => {},
881	1134	}
	1135	new_decl.generation = self.generation;
882	1136	return error.AnalysisFail;
883	1137	},
884	1138	};
...	...	@@ -893,34 +1147,37 @@ fn resolveDecl(
893	1147	},
894	1148	};
895	1149	new_decl.analysis = .complete;
	1150	new_decl.generation = self.generation;
896	1151	if (typed_value.ty.hasCodeGenBits()) {
897	1152	// We don't fully codegen the decl until later, but we do need to reserve a global
898	1153	// offset table index for it. This allows us to codegen decls out of dependency order,
899	1154	// increasing how many computations can be done in parallel.
900	1155	try self.bin_file.allocateDeclIndexes(new_decl);
901
902		// We ensureCapacity when scanning for decls.
903		self.work_queue.writeItemAssumeCapacity(.{ .codegen_decl = new_decl });
	1156	try self.work_queue.writeItem(.{ .codegen_decl = new_decl });
904	1157	}
905	1158	return new_decl;
906	1159	}
907	1160	}
908	1161
	1162	/// Declares a dependency on the decl.
909	1163	fn resolveCompleteDecl(self: Module, scope: Scope, old_inst: zir.Inst) InnerError!Decl {
910		const decl = try self.resolveDecl(scope, old_inst, link.ElfFile.Decl.empty);
	1164	const decl = try self.resolveDecl(scope, old_inst);
911	1165	switch (decl.analysis) {
912		.initial_in_progress => unreachable,
913		.repeat_in_progress => unreachable,
914		.initial_dependency_failure,
915		.repeat_dependency_failure,
916		.initial_sema_failure,
917		.repeat_sema_failure,
	1166	.in_progress => unreachable,
	1167	.outdated => unreachable,
	1168
	1169	.dependency_failure,
	1170	.sema_failure,
918	1171	.codegen_failure,
919	1172	.codegen_failure_retryable,
920	1173	=> return error.AnalysisFail,
921	1174
922		.complete => return decl,
	1175	.complete => {},
923	1176	}
	1177	if (scope.decl()) \|scope_decl\| {
	1178	try self.declareDeclDependency(scope_decl, decl);
	1179	}
	1180	return decl;
924	1181	}
925	1182
926	1183	fn resolveInst(self: Module, scope: Scope, old_inst: zir.Inst) InnerError!Inst {
...	...	@@ -998,13 +1255,14 @@ fn analyzeExport(self: Module, scope: Scope, export_inst: *zir.Inst.Export) In
998	1255	const new_export = try self.allocator.create(Export);
999	1256	errdefer self.allocator.destroy(new_export);
1000	1257
1001		const owner_decl = scope.decl();
	1258	const owner_decl = scope.decl().?;
1002	1259
1003	1260	new_export.* = .{
1004	1261	.options = .{ .name = symbol_name },
1005	1262	.src = export_inst.base.src,
1006	1263	.link = .{},
1007	1264	.owner_decl = owner_decl,
	1265	.exported_decl = exported_decl,
1008	1266	.status = .in_progress,
1009	1267	};
1010	1268
...	...	@@ -1327,7 +1585,7 @@ fn analyzeInstFn(self: Module, scope: Scope, fn_inst: *zir.Inst.Fn) InnerError
1327	1585	new_func.* = .{
1328	1586	.fn_type = fn_type,
1329	1587	.analysis = .{ .queued = fn_inst },
1330		.owner_decl = scope.decl(),
	1588	.owner_decl = scope.decl().?,
1331	1589	};
1332	1590	const fn_payload = try scope.arena().create(Value.Payload.Function);
1333	1591	fn_payload.* = .{ .func = new_func };
...	...	@@ -2024,11 +2282,7 @@ fn failWithOwnedErrorMsg(self: Module, scope: Scope, src: usize, err_msg: *Err
2024	2282	switch (scope.tag) {
2025	2283	.decl => {
2026	2284	const decl = scope.cast(Scope.DeclAnalysis).?.decl;
2027		switch (decl.analysis) {
2028		.initial_in_progress => decl.analysis = .initial_sema_failure,
2029		.repeat_in_progress => decl.analysis = .repeat_sema_failure,
2030		else => unreachable,
2031		}
	2285	decl.analysis = .sema_failure;
2032	2286	self.failed_decls.putAssumeCapacityNoClobber(decl, err_msg);
2033	2287	},
2034	2288	.block => {

src-self-hosted/link.zig+330-147

...	...	@@ -126,6 +126,10 @@ pub const ElfFile = struct {
126	126	local_symbols: std.ArrayListUnmanaged(elf.Elf64_Sym) = std.ArrayListUnmanaged(elf.Elf64_Sym){},
127	127	global_symbols: std.ArrayListUnmanaged(elf.Elf64_Sym) = std.ArrayListUnmanaged(elf.Elf64_Sym){},
128	128
	129	local_symbol_free_list: std.ArrayListUnmanaged(u32) = std.ArrayListUnmanaged(u32){},
	130	global_symbol_free_list: std.ArrayListUnmanaged(u32) = std.ArrayListUnmanaged(u32){},
	131	offset_table_free_list: std.ArrayListUnmanaged(u32) = std.ArrayListUnmanaged(u32){},
	132
129	133	/// Same order as in the file. The value is the absolute vaddr value.
130	134	/// If the vaddr of the executable program header changes, the entire
131	135	/// offset table needs to be rewritten.
...	...	@@ -138,11 +142,39 @@ pub const ElfFile = struct {
138	142
139	143	error_flags: ErrorFlags = ErrorFlags{},
140	144
	145	/// A list of text blocks that have surplus capacity. This list can have false
	146	/// positives, as functions grow and shrink over time, only sometimes being added
	147	/// or removed from the freelist.
	148	///
	149	/// A text block has surplus capacity when its overcapacity value is greater than
	150	/// minimum_text_block_size * alloc_num / alloc_den. That is, when it has so
	151	/// much extra capacity, that we could fit a small new symbol in it, itself with
	152	/// ideal_capacity or more.
	153	///
	154	/// Ideal capacity is defined by size * alloc_num / alloc_den.
	155	///
	156	/// Overcapacity is measured by actual_capacity - ideal_capacity. Note that
	157	/// overcapacity can be negative. A simple way to have negative overcapacity is to
	158	/// allocate a fresh text block, which will have ideal capacity, and then grow it
	159	/// by 1 byte. It will then have -1 overcapacity.
	160	text_block_free_list: std.ArrayListUnmanaged(TextBlock) = std.ArrayListUnmanaged(TextBlock){},
	161	last_text_block: ?*TextBlock = null,
	162
	163	/// `alloc_num / alloc_den` is the factor of padding when allocating.
	164	const alloc_num = 4;
	165	const alloc_den = 3;
	166
	167	/// In order for a slice of bytes to be considered eligible to keep metadata pointing at
	168	/// it as a possible place to put new symbols, it must have enough room for this many bytes
	169	/// (plus extra for reserved capacity).
	170	const minimum_text_block_size = 64;
	171	const min_text_capacity = minimum_text_block_size * alloc_num / alloc_den;
	172
141	173	pub const ErrorFlags = struct {
142	174	no_entry_point_found: bool = false,
143	175	};
144	176
145		pub const Decl = struct {
	177	pub const TextBlock = struct {
146	178	/// Each decl always gets a local symbol with the fully qualified name.
147	179	/// The vaddr and size are found here directly.
148	180	/// The file offset is found by computing the vaddr offset from the section vaddr
...	...	@@ -152,11 +184,43 @@ pub const ElfFile = struct {
152	184	local_sym_index: u32,
153	185	/// This field is undefined for symbols with size = 0.
154	186	offset_table_index: u32,
	187	/// Points to the previous and next neighbors, based on the `text_offset`.
	188	/// This can be used to find, for example, the capacity of this `TextBlock`.
	189	prev: ?*TextBlock,
	190	next: ?*TextBlock,
155	191
156		pub const empty = Decl{
	192	pub const empty = TextBlock{
157	193	.local_sym_index = 0,
158	194	.offset_table_index = undefined,
	195	.prev = null,
	196	.next = null,
159	197	};
	198
	199	/// Returns how much room there is to grow in virtual address space.
	200	/// File offset relocation happens transparently, so it is not included in
	201	/// this calculation.
	202	fn capacity(self: TextBlock, elf_file: ElfFile) u64 {
	203	const self_sym = elf_file.local_symbols.items[self.local_sym_index];
	204	if (self.next) \|next\| {
	205	const next_sym = elf_file.local_symbols.items[next.local_sym_index];
	206	return next_sym.st_value - self_sym.st_value;
	207	} else {
	208	// We are the last block. The capacity is limited only by virtual address space.
	209	return std.math.maxInt(u32) - self_sym.st_value;
	210	}
	211	}
	212
	213	fn freeListEligible(self: TextBlock, elf_file: ElfFile) bool {
	214	// No need to keep a free list node for the last block.
	215	const next = self.next orelse return false;
	216	const self_sym = elf_file.local_symbols.items[self.local_sym_index];
	217	const next_sym = elf_file.local_symbols.items[next.local_sym_index];
	218	const cap = next_sym.st_value - self_sym.st_value;
	219	const ideal_cap = self_sym.st_size * alloc_num / alloc_den;
	220	if (cap <= ideal_cap) return false;
	221	const surplus = cap - ideal_cap;
	222	return surplus >= min_text_capacity;
	223	}
160	224	};
161	225
162	226	pub const Export = struct {
...	...	@@ -169,6 +233,10 @@ pub const ElfFile = struct {
169	233	self.shstrtab.deinit(self.allocator);
170	234	self.local_symbols.deinit(self.allocator);
171	235	self.global_symbols.deinit(self.allocator);
	236	self.global_symbol_free_list.deinit(self.allocator);
	237	self.local_symbol_free_list.deinit(self.allocator);
	238	self.offset_table_free_list.deinit(self.allocator);
	239	self.text_block_free_list.deinit(self.allocator);
172	240	self.offset_table.deinit(self.allocator);
173	241	if (self.owns_file_handle) {
174	242	if (self.file) \|f\| f.close();
...	...	@@ -193,10 +261,6 @@ pub const ElfFile = struct {
193	261	});
194	262	}
195	263
196		// `alloc_num / alloc_den` is the factor of padding when allocation
197		const alloc_num = 4;
198		const alloc_den = 3;
199
200	264	/// Returns end pos of collision, if any.
201	265	fn detectAllocCollision(self: *ElfFile, start: u64, size: u64) ?u64 {
202	266	const small_ptr = self.options.target.cpu.arch.ptrBitWidth() == 32;
...	...	@@ -448,6 +512,13 @@ pub const ElfFile = struct {
448	512	self.phdr_table_offset = self.findFreeSpace(self.program_headers.items.len * phsize, phalign);
449	513	self.phdr_table_dirty = true;
450	514	}
	515	{
	516	// Iterate over symbols, populating free_list and last_text_block.
	517	if (self.local_symbols.items.len != 1) {
	518	@panic("TODO implement setting up free_list and last_text_block from existing ELF file");
	519	}
	520	// We are starting with an empty file. The default values are correct, null and empty list.
	521	}
451	522	}
452	523
453	524	/// Commit pending changes and write headers.
...	...	@@ -577,7 +648,6 @@ pub const ElfFile = struct {
577	648	self.error_flags.no_entry_point_found = false;
578	649	try self.writeElfHeader();
579	650	}
580		// TODO find end pos and truncate
581	651
582	652	// The point of flush() is to commit changes, so nothing should be dirty after this.
583	653	assert(!self.phdr_table_dirty);
...	...	@@ -709,100 +779,222 @@ pub const ElfFile = struct {
709	779	try self.file.?.pwriteAll(hdr_buf[0..index], 0);
710	780	}
711	781
712		const AllocatedBlock = struct {
713		vaddr: u64,
714		file_offset: u64,
715		size_capacity: u64,
716		};
	782	fn freeTextBlock(self: ElfFile, text_block: TextBlock) void {
	783	var already_have_free_list_node = false;
	784	{
	785	var i: usize = 0;
	786	while (i < self.text_block_free_list.items.len) {
	787	if (self.text_block_free_list.items[i] == text_block) {
	788	_ = self.text_block_free_list.swapRemove(i);
	789	continue;
	790	}
	791	if (self.text_block_free_list.items[i] == text_block.prev) {
	792	already_have_free_list_node = true;
	793	}
	794	i += 1;
	795	}
	796	}
717	797
718		fn allocateTextBlock(self: *ElfFile, new_block_size: u64, alignment: u64) !AllocatedBlock {
719		const phdr = &self.program_headers.items[self.phdr_load_re_index.?];
720		const shdr = &self.sections.items[self.text_section_index.?];
	798	if (self.last_text_block == text_block) {
	799	// TODO shrink the .text section size here
	800	self.last_text_block = text_block.prev;
	801	}
721	802
722		// TODO Also detect virtual address collisions.
723		const text_capacity = self.allocatedSize(shdr.sh_offset);
724		// TODO instead of looping here, maintain a free list and a pointer to the end.
725		var last_start: u64 = phdr.p_vaddr;
726		var last_size: u64 = 0;
727		for (self.local_symbols.items) \|sym\| {
728		if (sym.st_value + sym.st_size > last_start + last_size) {
729		last_start = sym.st_value;
730		last_size = sym.st_size;
	803	if (text_block.prev) \|prev\| {
	804	prev.next = text_block.next;
	805
	806	if (!already_have_free_list_node and prev.freeListEligible(self.*)) {
	807	// The free list is heuristics, it doesn't have to be perfect, so we can
	808	// ignore the OOM here.
	809	self.text_block_free_list.append(self.allocator, prev) catch {};
731	810	}
	811	} else {
	812	text_block.prev = null;
732	813	}
733		const end_vaddr = last_start + (last_size * alloc_num / alloc_den);
734		const aligned_start_vaddr = mem.alignForwardGeneric(u64, end_vaddr, alignment);
735		const needed_size = (aligned_start_vaddr + new_block_size) - phdr.p_vaddr;
736		if (needed_size > text_capacity) {
737		// Must move the entire text section.
738		const new_offset = self.findFreeSpace(needed_size, 0x1000);
739		const text_size = (last_start + last_size) - phdr.p_vaddr;
740		const amt = try self.file.?.copyRangeAll(shdr.sh_offset, self.file.?, new_offset, text_size);
741		if (amt != text_size) return error.InputOutput;
742		shdr.sh_offset = new_offset;
743		phdr.p_offset = new_offset;
	814
	815	if (text_block.next) \|next\| {
	816	next.prev = text_block.prev;
	817	} else {
	818	text_block.next = null;
744	819	}
745		// Now that we know the code size, we need to update the program header for executable code
746		shdr.sh_size = needed_size;
747		phdr.p_memsz = needed_size;
748		phdr.p_filesz = needed_size;
749
750		self.phdr_table_dirty = true; // TODO look into making only the one program header dirty
751		self.shdr_table_dirty = true; // TODO look into making only the one section dirty
752
753		return AllocatedBlock{
754		.vaddr = aligned_start_vaddr,
755		.file_offset = shdr.sh_offset + (aligned_start_vaddr - phdr.p_vaddr),
756		.size_capacity = text_capacity - needed_size,
757		};
758	820	}
759	821
760		fn findAllocatedTextBlock(self: *ElfFile, sym: elf.Elf64_Sym) AllocatedBlock {
	822	fn shrinkTextBlock(self: ElfFile, text_block: TextBlock, new_block_size: u64) void {
	823	// TODO check the new capacity, and if it crosses the size threshold into a big enough
	824	// capacity, insert a free list node for it.
	825	}
	826
	827	fn growTextBlock(self: ElfFile, text_block: TextBlock, new_block_size: u64, alignment: u64) !u64 {
	828	const sym = self.local_symbols.items[text_block.local_sym_index];
	829	const align_ok = mem.alignBackwardGeneric(u64, sym.st_value, alignment) == sym.st_value;
	830	const need_realloc = !align_ok or new_block_size > text_block.capacity(self.*);
	831	if (!need_realloc) return sym.st_value;
	832	return self.allocateTextBlock(text_block, new_block_size, alignment);
	833	}
	834
	835	fn allocateTextBlock(self: ElfFile, text_block: TextBlock, new_block_size: u64, alignment: u64) !u64 {
761	836	const phdr = &self.program_headers.items[self.phdr_load_re_index.?];
762	837	const shdr = &self.sections.items[self.text_section_index.?];
	838	const new_block_ideal_capacity = new_block_size * alloc_num / alloc_den;
	839
	840	// We use these to indicate our intention to update metadata, placing the new block,
	841	// and possibly removing a free list node.
	842	// It would be simpler to do it inside the for loop below, but that would cause a
	843	// problem if an error was returned later in the function. So this action
	844	// is actually carried out at the end of the function, when errors are no longer possible.
	845	var block_placement: ?*TextBlock = null;
	846	var free_list_removal: ?usize = null;
	847
	848	// First we look for an appropriately sized free list node.
	849	// The list is unordered. We'll just take the first thing that works.
	850	const vaddr = blk: {
	851	var i: usize = 0;
	852	while (i < self.text_block_free_list.items.len) {
	853	const big_block = self.text_block_free_list.items[i];
	854	// We now have a pointer to a live text block that has too much capacity.
	855	// Is it enough that we could fit this new text block?
	856	const sym = self.local_symbols.items[big_block.local_sym_index];
	857	const capacity = big_block.capacity(self.*);
	858	const ideal_capacity = capacity * alloc_num / alloc_den;
	859	const ideal_capacity_end_vaddr = sym.st_value + ideal_capacity;
	860	const capacity_end_vaddr = sym.st_value + capacity;
	861	const new_start_vaddr_unaligned = capacity_end_vaddr - new_block_ideal_capacity;
	862	const new_start_vaddr = mem.alignBackwardGeneric(u64, new_start_vaddr_unaligned, alignment);
	863	if (new_start_vaddr < ideal_capacity_end_vaddr) {
	864	// Additional bookkeeping here to notice if this free list node
	865	// should be deleted because the block that it points to has grown to take up
	866	// more of the extra capacity.
	867	if (!big_block.freeListEligible(self.*)) {
	868	_ = self.text_block_free_list.swapRemove(i);
	869	} else {
	870	i += 1;
	871	}
	872	continue;
	873	}
	874	// At this point we know that we will place the new block here. But the
	875	// remaining question is whether there is still yet enough capacity left
	876	// over for there to still be a free list node.
	877	const remaining_capacity = new_start_vaddr - ideal_capacity_end_vaddr;
	878	const keep_free_list_node = remaining_capacity >= min_text_capacity;
	879
	880	// Set up the metadata to be updated, after errors are no longer possible.
	881	block_placement = big_block;
	882	if (!keep_free_list_node) {
	883	free_list_removal = i;
	884	}
	885	break :blk new_start_vaddr;
	886	} else if (self.last_text_block) \|last\| {
	887	const sym = self.local_symbols.items[last.local_sym_index];
	888	const ideal_capacity = sym.st_size * alloc_num / alloc_den;
	889	const ideal_capacity_end_vaddr = sym.st_value + ideal_capacity;
	890	const new_start_vaddr = mem.alignForwardGeneric(u64, ideal_capacity_end_vaddr, alignment);
	891	// Set up the metadata to be updated, after errors are no longer possible.
	892	block_placement = last;
	893	break :blk new_start_vaddr;
	894	} else {
	895	break :blk phdr.p_vaddr;
	896	}
	897	};
	898
	899	const expand_text_section = block_placement == null or block_placement.?.next == null;
	900	if (expand_text_section) {
	901	const text_capacity = self.allocatedSize(shdr.sh_offset);
	902	const needed_size = (vaddr + new_block_size) - phdr.p_vaddr;
	903	if (needed_size > text_capacity) {
	904	// Must move the entire text section.
	905	const new_offset = self.findFreeSpace(needed_size, 0x1000);
	906	const text_size = if (self.last_text_block) \|last\| blk: {
	907	const sym = self.local_symbols.items[last.local_sym_index];
	908	break :blk (sym.st_value + sym.st_size) - phdr.p_vaddr;
	909	} else 0;
	910	const amt = try self.file.?.copyRangeAll(shdr.sh_offset, self.file.?, new_offset, text_size);
	911	if (amt != text_size) return error.InputOutput;
	912	shdr.sh_offset = new_offset;
	913	phdr.p_offset = new_offset;
	914	}
	915	self.last_text_block = text_block;
763	916
764		// Find the next sym after this one.
765		// TODO look into using a hash map to speed up perf.
766		const text_capacity = self.allocatedSize(shdr.sh_offset);
767		var next_vaddr_start = phdr.p_vaddr + text_capacity;
768		for (self.local_symbols.items) \|elem\| {
769		if (elem.st_value < sym.st_value) continue;
770		if (elem.st_value < next_vaddr_start) next_vaddr_start = elem.st_value;
	917	shdr.sh_size = needed_size;
	918	phdr.p_memsz = needed_size;
	919	phdr.p_filesz = needed_size;
	920
	921	self.phdr_table_dirty = true; // TODO look into making only the one program header dirty
	922	self.shdr_table_dirty = true; // TODO look into making only the one section dirty
771	923	}
772		return .{
773		.vaddr = sym.st_value,
774		.file_offset = shdr.sh_offset + (sym.st_value - phdr.p_vaddr),
775		.size_capacity = next_vaddr_start - sym.st_value,
776		};
	924
	925	// This function can also reallocate a text block.
	926	// In this case we need to "unplug" it from its previous location before
	927	// plugging it in to its new location.
	928	if (text_block.prev) \|prev\| {
	929	prev.next = text_block.next;
	930	}
	931	if (text_block.next) \|next\| {
	932	next.prev = text_block.prev;
	933	}
	934
	935	if (block_placement) \|big_block\| {
	936	text_block.prev = big_block;
	937	text_block.next = big_block.next;
	938	big_block.next = text_block;
	939	} else {
	940	text_block.prev = null;
	941	text_block.next = null;
	942	}
	943	if (free_list_removal) \|i\| {
	944	_ = self.text_block_free_list.swapRemove(i);
	945	}
	946	return vaddr;
777	947	}
778	948
779	949	pub fn allocateDeclIndexes(self: ElfFile, decl: Module.Decl) !void {
780	950	if (decl.link.local_sym_index != 0) return;
781	951
	952	// Here we also ensure capacity for the free lists so that they can be appended to without fail.
782	953	try self.local_symbols.ensureCapacity(self.allocator, self.local_symbols.items.len + 1);
	954	try self.local_symbol_free_list.ensureCapacity(self.allocator, self.local_symbols.items.len);
783	955	try self.offset_table.ensureCapacity(self.allocator, self.offset_table.items.len + 1);
784		const local_sym_index = self.local_symbols.items.len;
785		const offset_table_index = self.offset_table.items.len;
	956	try self.offset_table_free_list.ensureCapacity(self.allocator, self.local_symbols.items.len);
	957
	958	if (self.local_symbol_free_list.popOrNull()) \|i\| {
	959	//std.debug.warn("reusing symbol index {} for {}\n", .{i, decl.name});
	960	decl.link.local_sym_index = i;
	961	} else {
	962	//std.debug.warn("allocating symbol index {} for {}\n", .{self.local_symbols.items.len, decl.name});
	963	decl.link.local_sym_index = @intCast(u32, self.local_symbols.items.len);
	964	_ = self.local_symbols.addOneAssumeCapacity();
	965	}
	966
	967	if (self.offset_table_free_list.popOrNull()) \|i\| {
	968	decl.link.offset_table_index = i;
	969	} else {
	970	decl.link.offset_table_index = @intCast(u32, self.offset_table.items.len);
	971	_ = self.offset_table.addOneAssumeCapacity();
	972	self.offset_table_count_dirty = true;
	973	}
	974
786	975	const phdr = &self.program_headers.items[self.phdr_load_re_index.?];
787	976
788		self.local_symbols.appendAssumeCapacity(.{
	977	self.local_symbols.items[decl.link.local_sym_index] = .{
789	978	.st_name = 0,
790	979	.st_info = 0,
791	980	.st_other = 0,
792	981	.st_shndx = 0,
793	982	.st_value = phdr.p_vaddr,
794	983	.st_size = 0,
795		});
796		errdefer self.local_symbols.shrink(self.allocator, self.local_symbols.items.len - 1);
797		self.offset_table.appendAssumeCapacity(0);
798		errdefer self.offset_table.shrink(self.allocator, self.offset_table.items.len - 1);
	984	};
	985	self.offset_table.items[decl.link.offset_table_index] = 0;
	986	}
799	987
800		self.offset_table_count_dirty = true;
	988	pub fn freeDecl(self: ElfFile, decl: Module.Decl) void {
	989	self.freeTextBlock(&decl.link);
	990	if (decl.link.local_sym_index != 0) {
	991	self.local_symbol_free_list.appendAssumeCapacity(decl.link.local_sym_index);
	992	self.offset_table_free_list.appendAssumeCapacity(decl.link.offset_table_index);
801	993
802		decl.link = .{
803		.local_sym_index = @intCast(u32, local_sym_index),
804		.offset_table_index = @intCast(u32, offset_table_index),
805		};
	994	self.local_symbols.items[decl.link.local_sym_index].st_info = 0;
	995
	996	decl.link.local_sym_index = 0;
	997	}
806	998	}
807	999
808	1000	pub fn updateDecl(self: ElfFile, module: Module, decl: *Module.Decl) !void {
...	...	@@ -822,80 +1014,60 @@ pub const ElfFile = struct {
822	1014
823	1015	const required_alignment = typed_value.ty.abiAlignment(self.options.target);
824	1016
825		const file_offset = blk: {
826		const stt_bits: u8 = switch (typed_value.ty.zigTypeTag()) {
827		.Fn => elf.STT_FUNC,
828		else => elf.STT_OBJECT,
829		};
	1017	const stt_bits: u8 = switch (typed_value.ty.zigTypeTag()) {
	1018	.Fn => elf.STT_FUNC,
	1019	else => elf.STT_OBJECT,
	1020	};
830	1021
831		if (decl.link.local_sym_index != 0) {
832		const local_sym = &self.local_symbols.items[decl.link.local_sym_index];
833		const existing_block = self.findAllocatedTextBlock(local_sym.*);
834		const need_realloc = local_sym.st_size == 0 or
835		code.len > existing_block.size_capacity or
836		!mem.isAlignedGeneric(u64, local_sym.st_value, required_alignment);
837		// TODO check for collision with another symbol
838		const file_offset = if (need_realloc) fo: {
839		const new_block = try self.allocateTextBlock(code.len, required_alignment);
840		local_sym.st_value = new_block.vaddr;
841		self.offset_table.items[decl.link.offset_table_index] = new_block.vaddr;
842
843		//std.debug.warn("{}: writing got index {}=0x{x}\n", .{
844		// decl.name,
845		// decl.link.offset_table_index,
846		// self.offset_table.items[decl.link.offset_table_index],
847		//});
	1022	assert(decl.link.local_sym_index != 0); // Caller forgot to allocateDeclIndexes()
	1023	const local_sym = &self.local_symbols.items[decl.link.local_sym_index];
	1024	if (local_sym.st_size != 0) {
	1025	const capacity = decl.link.capacity(self.*);
	1026	const need_realloc = code.len > capacity or
	1027	!mem.isAlignedGeneric(u64, local_sym.st_value, required_alignment);
	1028	if (need_realloc) {
	1029	const vaddr = try self.growTextBlock(&decl.link, code.len, required_alignment);
	1030	//std.debug.warn("growing {} from 0x{x} to 0x{x}\n", .{ decl.name, local_sym.st_value, vaddr });
	1031	if (vaddr != local_sym.st_value) {
	1032	local_sym.st_value = vaddr;
	1033
	1034	//std.debug.warn(" (writing new offset table entry)\n", .{});
	1035	self.offset_table.items[decl.link.offset_table_index] = vaddr;
848	1036	try self.writeOffsetTableEntry(decl.link.offset_table_index);
849
850		break :fo new_block.file_offset;
851		} else existing_block.file_offset;
852		local_sym.st_size = code.len;
853		local_sym.st_name = try self.updateString(local_sym.st_name, mem.spanZ(decl.name));
854		local_sym.st_info = (elf.STB_LOCAL << 4) \| stt_bits;
855		local_sym.st_other = 0;
856		local_sym.st_shndx = self.text_section_index.?;
857		// TODO this write could be avoided if no fields of the symbol were changed.
858		try self.writeSymbol(decl.link.local_sym_index);
859
860		//std.debug.warn("updating {} at vaddr 0x{x}\n", .{ decl.name, local_sym.st_value });
861		break :blk file_offset;
862		} else {
863		try self.local_symbols.ensureCapacity(self.allocator, self.local_symbols.items.len + 1);
864		try self.offset_table.ensureCapacity(self.allocator, self.offset_table.items.len + 1);
865		const decl_name = mem.spanZ(decl.name);
866		const name_str_index = try self.makeString(decl_name);
867		const new_block = try self.allocateTextBlock(code.len, required_alignment);
868		const local_sym_index = self.local_symbols.items.len;
869		const offset_table_index = self.offset_table.items.len;
870
871		//std.debug.warn("add symbol for {} at vaddr 0x{x}, size {}\n", .{ decl.name, new_block.vaddr, code.len });
872		self.local_symbols.appendAssumeCapacity(.{
873		.st_name = name_str_index,
874		.st_info = (elf.STB_LOCAL << 4) \| stt_bits,
875		.st_other = 0,
876		.st_shndx = self.text_section_index.?,
877		.st_value = new_block.vaddr,
878		.st_size = code.len,
879		});
880		errdefer self.local_symbols.shrink(self.allocator, self.local_symbols.items.len - 1);
881		self.offset_table.appendAssumeCapacity(new_block.vaddr);
882		errdefer self.offset_table.shrink(self.allocator, self.offset_table.items.len - 1);
883
884		self.offset_table_count_dirty = true;
885
886		try self.writeSymbol(local_sym_index);
887		try self.writeOffsetTableEntry(offset_table_index);
888
889		decl.link = .{
890		.local_sym_index = @intCast(u32, local_sym_index),
891		.offset_table_index = @intCast(u32, offset_table_index),
892		};
893
894		//std.debug.warn("writing new {} at vaddr 0x{x}\n", .{ decl.name, new_block.vaddr });
895		break :blk new_block.file_offset;
	1037	}
	1038	} else if (code.len < local_sym.st_size) {
	1039	self.shrinkTextBlock(&decl.link, code.len);
896	1040	}
897		};
	1041	local_sym.st_size = code.len;
	1042	local_sym.st_name = try self.updateString(local_sym.st_name, mem.spanZ(decl.name));
	1043	local_sym.st_info = (elf.STB_LOCAL << 4) \| stt_bits;
	1044	local_sym.st_other = 0;
	1045	local_sym.st_shndx = self.text_section_index.?;
	1046	// TODO this write could be avoided if no fields of the symbol were changed.
	1047	try self.writeSymbol(decl.link.local_sym_index);
	1048	} else {
	1049	const decl_name = mem.spanZ(decl.name);
	1050	const name_str_index = try self.makeString(decl_name);
	1051	const vaddr = try self.allocateTextBlock(&decl.link, code.len, required_alignment);
	1052	//std.debug.warn("allocated text block for {} at 0x{x}\n", .{ decl_name, vaddr });
	1053	errdefer self.freeTextBlock(&decl.link);
	1054
	1055	local_sym.* = .{
	1056	.st_name = name_str_index,
	1057	.st_info = (elf.STB_LOCAL << 4) \| stt_bits,
	1058	.st_other = 0,
	1059	.st_shndx = self.text_section_index.?,
	1060	.st_value = vaddr,
	1061	.st_size = code.len,
	1062	};
	1063	self.offset_table.items[decl.link.offset_table_index] = vaddr;
898	1064
	1065	try self.writeSymbol(decl.link.local_sym_index);
	1066	try self.writeOffsetTableEntry(decl.link.offset_table_index);
	1067	}
	1068
	1069	const section_offset = local_sym.st_value - self.program_headers.items[self.phdr_load_re_index.?].p_vaddr;
	1070	const file_offset = self.sections.items[self.text_section_index.?].sh_offset + section_offset;
899	1071	try self.file.?.pwriteAll(code, file_offset);
900	1072
901	1073	// Since we updated the vaddr and the size, each corresponding export symbol also needs to be updated.
...	...	@@ -910,7 +1082,10 @@ pub const ElfFile = struct {
910	1082	decl: *const Module.Decl,
911	1083	exports: []const *Module.Export,
912	1084	) !void {
	1085	// In addition to ensuring capacity for global_symbols, we also ensure capacity for freeing all of
	1086	// them, so that deleting exports is guaranteed to succeed.
913	1087	try self.global_symbols.ensureCapacity(self.allocator, self.global_symbols.items.len + exports.len);
	1088	try self.global_symbol_free_list.ensureCapacity(self.allocator, self.global_symbols.items.len);
914	1089	const typed_value = decl.typed_value.most_recent.typed_value;
915	1090	if (decl.link.local_sym_index == 0) return;
916	1091	const decl_sym = self.local_symbols.items[decl.link.local_sym_index];
...	...	@@ -957,22 +1132,30 @@ pub const ElfFile = struct {
957	1132	};
958	1133	} else {
959	1134	const name = try self.makeString(exp.options.name);
960		const i = self.global_symbols.items.len;
961		self.global_symbols.appendAssumeCapacity(.{
	1135	const i = if (self.global_symbol_free_list.popOrNull()) \|i\| i else blk: {
	1136	_ = self.global_symbols.addOneAssumeCapacity();
	1137	break :blk self.global_symbols.items.len - 1;
	1138	};
	1139	self.global_symbols.items[i] = .{
962	1140	.st_name = name,
963	1141	.st_info = (stb_bits << 4) \| stt_bits,
964	1142	.st_other = 0,
965	1143	.st_shndx = self.text_section_index.?,
966	1144	.st_value = decl_sym.st_value,
967	1145	.st_size = decl_sym.st_size,
968		});
969		errdefer self.global_symbols.shrink(self.allocator, self.global_symbols.items.len - 1);
	1146	};
970	1147
971	1148	exp.link.sym_index = @intCast(u32, i);
972	1149	}
973	1150	}
974	1151	}
975	1152
	1153	pub fn deleteExport(self: *ElfFile, exp: Export) void {
	1154	const sym_index = exp.sym_index orelse return;
	1155	self.global_symbol_free_list.appendAssumeCapacity(sym_index);
	1156	self.global_symbols.items[sym_index].st_info = 0;
	1157	}
	1158
976	1159	fn writeProgHeader(self: *ElfFile, index: usize) !void {
977	1160	const foreign_endian = self.options.target.cpu.arch.endian() != std.Target.current.cpu.arch.endian();
978	1161	const offset = self.program_headers.items[index].p_offset;

src-self-hosted/type.zig+27-11

...	...	@@ -92,13 +92,13 @@ pub const Type = extern union {
92	92	return @fieldParentPtr(T, "base", self.ptr_otherwise);
93	93	}
94	94
95		pub fn eql(self: Type, other: Type) bool {
96		//std.debug.warn("test {} == {}\n", .{ self, other });
	95	pub fn eql(a: Type, b: Type) bool {
	96	//std.debug.warn("test {} == {}\n", .{ a, b });
97	97	// As a shortcut, if the small tags / addresses match, we're done.
98		if (self.tag_if_small_enough == other.tag_if_small_enough)
	98	if (a.tag_if_small_enough == b.tag_if_small_enough)
99	99	return true;
100		const zig_tag_a = self.zigTypeTag();
101		const zig_tag_b = self.zigTypeTag();
	100	const zig_tag_a = a.zigTypeTag();
	101	const zig_tag_b = b.zigTypeTag();
102	102	if (zig_tag_a != zig_tag_b)
103	103	return false;
104	104	switch (zig_tag_a) {
...	...	@@ -111,24 +111,40 @@ pub const Type = extern union {
111	111	.Undefined => return true,
112	112	.Null => return true,
113	113	.Pointer => {
114		const is_slice_a = isSlice(self);
115		const is_slice_b = isSlice(other);
	114	const is_slice_a = isSlice(a);
	115	const is_slice_b = isSlice(b);
116	116	if (is_slice_a != is_slice_b)
117	117	return false;
118	118	@panic("TODO implement more pointer Type equality comparison");
119	119	},
120	120	.Int => {
121		if (self.tag() != other.tag()) {
	121	if (a.tag() != b.tag()) {
122	122	// Detect that e.g. u64 != usize, even if the bits match on a particular target.
123	123	return false;
124	124	}
125	125	// The target will not be branched upon, because we handled target-dependent cases above.
126		const info_a = self.intInfo(@as(Target, undefined));
127		const info_b = self.intInfo(@as(Target, undefined));
	126	const info_a = a.intInfo(@as(Target, undefined));
	127	const info_b = b.intInfo(@as(Target, undefined));
128	128	return info_a.signed == info_b.signed and info_a.bits == info_b.bits;
129	129	},
	130	.Array => {
	131	if (a.arrayLen() != b.arrayLen())
	132	return false;
	133	if (a.elemType().eql(b.elemType()))
	134	return false;
	135	const sentinel_a = a.arraySentinel();
	136	const sentinel_b = b.arraySentinel();
	137	if (sentinel_a) \|sa\| {
	138	if (sentinel_b) \|sb\| {
	139	return sa.eql(sb);
	140	} else {
	141	return false;
	142	}
	143	} else {
	144	return sentinel_b == null;
	145	}
	146	},
130	147	.Float,
131		.Array,
132	148	.Struct,
133	149	.Optional,
134	150	.ErrorUnion,

src-self-hosted/value.zig+5

...	...	@@ -666,6 +666,11 @@ pub const Value = extern union {
666	666	return orderAgainstZero(lhs).compare(op);
667	667	}
668	668
	669	pub fn eql(a: Value, b: Value) bool {
	670	// TODO non numerical comparisons
	671	return compare(a, .eq, b);
	672	}
	673
669	674	pub fn toBool(self: Value) bool {
670	675	return switch (self.tag()) {
671	676	.bool_true => true,

src-self-hosted/zir.zig+10

...	...	@@ -442,6 +442,16 @@ pub const Module = struct {
442	442
443	443	const InstPtrTable = std.AutoHashMap(Inst, struct { index: usize, fn_body: ?Module.Body });
444	444
	445	/// TODO Look into making a table to speed this up.
	446	pub fn findDecl(self: Module, name: []const u8) ?*Inst {
	447	for (self.decls) \|decl\| {
	448	if (mem.eql(u8, decl.name, name)) {
	449	return decl;
	450	}
	451	}
	452	return null;
	453	}
	454
445	455	/// The allocator is used for temporary storage, but this function always returns
446	456	/// with no resources allocated.
447	457	pub fn writeToStream(self: Module, allocator: *Allocator, stream: var) !void {

test/stage2/zir.zig+71

...	...	@@ -200,6 +200,73 @@ pub fn addCases(ctx: *TestContext) void {
200	200	\\@9 = str("_start")
201	201	\\@10 = ref(@9)
202	202	\\@11 = export(@10, @start)
	203	,
	204	\\@noreturn = primitive(noreturn)
	205	\\@void = primitive(void)
	206	\\@usize = primitive(usize)
	207	\\@0 = int(0)
	208	\\@1 = int(1)
	209	\\@2 = int(2)
	210	\\@3 = int(3)
	211	\\
	212	\\@syscall_array = str("syscall")
	213	\\@sysoutreg_array = str("={rax}")
	214	\\@rax_array = str("{rax}")
	215	\\@rdi_array = str("{rdi}")
	216	\\@rcx_array = str("rcx")
	217	\\@r11_array = str("r11")
	218	\\@rdx_array = str("{rdx}")
	219	\\@rsi_array = str("{rsi}")
	220	\\@memory_array = str("memory")
	221	\\@len_array = str("len")
	222	\\
	223	\\@msg = str("Hello, world!\n")
	224	\\@msg2 = str("Editing the same msg2 decl but this time with a much longer message which will\ncause the data to need to be relocated in virtual address space.\n")
	225	\\
	226	\\@start_fnty = fntype([], @noreturn, cc=Naked)
	227	\\@start = fn(@start_fnty, {
	228	\\ %SYS_exit_group = int(231)
	229	\\ %exit_code = as(@usize, @0)
	230	\\
	231	\\ %syscall = ref(@syscall_array)
	232	\\ %sysoutreg = ref(@sysoutreg_array)
	233	\\ %rax = ref(@rax_array)
	234	\\ %rdi = ref(@rdi_array)
	235	\\ %rcx = ref(@rcx_array)
	236	\\ %rdx = ref(@rdx_array)
	237	\\ %rsi = ref(@rsi_array)
	238	\\ %r11 = ref(@r11_array)
	239	\\ %memory = ref(@memory_array)
	240	\\
	241	\\ %SYS_write = as(@usize, @1)
	242	\\ %STDOUT_FILENO = as(@usize, @1)
	243	\\
	244	\\ %msg_ptr = ref(@msg2)
	245	\\ %msg_addr = ptrtoint(%msg_ptr)
	246	\\
	247	\\ %len_name = ref(@len_array)
	248	\\ %msg_len_ptr = fieldptr(%msg_ptr, %len_name)
	249	\\ %msg_len = deref(%msg_len_ptr)
	250	\\ %rc_write = asm(%syscall, @usize,
	251	\\ volatile=1,
	252	\\ output=%sysoutreg,
	253	\\ inputs=[%rax, %rdi, %rsi, %rdx],
	254	\\ clobbers=[%rcx, %r11, %memory],
	255	\\ args=[%SYS_write, %STDOUT_FILENO, %msg_addr, %msg_len])
	256	\\
	257	\\ %rc_exit = asm(%syscall, @usize,
	258	\\ volatile=1,
	259	\\ output=%sysoutreg,
	260	\\ inputs=[%rax, %rdi],
	261	\\ clobbers=[%rcx, %r11, %memory],
	262	\\ args=[%SYS_exit_group, %exit_code])
	263	\\
	264	\\ %99 = unreachable()
	265	\\});
	266	\\
	267	\\@9 = str("_start")
	268	\\@10 = ref(@9)
	269	\\@11 = export(@10, @start)
203	270	},
204	271	&[_][]const u8{
205	272	\\Hello, world!
...	...	@@ -207,6 +274,10 @@ pub fn addCases(ctx: *TestContext) void {
207	274	,
208	275	\\HELL WORLD
209	276	\\
	277	,
	278	\\Editing the same msg2 decl but this time with a much longer message which will
	279	\\cause the data to need to be relocated in virtual address space.
	280	\\
210	281	},
211	282	);
212	283