Commit 1544625df3fb4732f2cd63d1e7c4c738d1b7d0c0 | zig

author	Luuk de Gram <luuk@degram.dev> 2022-08-19 21:15:16+02:00
committer	Luuk de Gram <luuk@degram.dev> 2022-08-20 14:50:11+02:00
log	1544625df3fb4732f2cd63d1e7c4c738d1b7d0c0
tree	9daf0a93df0113b19f2f0747ca7a645b2123feec
parent	aca911ca18d43fddcc3d36f44d3750d07b53fb56
signature	Commit is signed but in an unrecognized format.

wasm/Object: parse using the correct file size

When an object file is being parsed from within an archive
file, we provide the object file size to ensure we do not
read past the object file. This is because follow up object
files can exist there, as well as an LF character to notate
the end of the file was reached. Such a character is invalid
within the object file.

This also fixes a bug in getting the function/global type
for defined globals/functions from object files as it was missing
the substraction with the import count of the respective type.

3 files changed, 31 insertions(+), 8 deletions(-)

src
- link
  - Wasm.zig
  - Wasm
    Archive.zig
    Object.zig

src/link/Wasm.zig+8-5

...	...	@@ -378,7 +378,7 @@ fn parseObjectFile(self: *Wasm, path: []const u8) !bool {
378	378	const file = try fs.cwd().openFile(path, .{});
379	379	errdefer file.close();
380	380
381		var object = Object.create(self.base.allocator, file, path) catch \|err\| switch (err) {
	381	var object = Object.create(self.base.allocator, file, path, null) catch \|err\| switch (err) {
382	382	error.InvalidMagicByte, error.NotObjectFile => return false,
383	383	else => \|e\| return e,
384	384	};
...	...	@@ -595,8 +595,8 @@ fn resolveSymbolsInArchives(self: *Wasm) !void {
595	595	// Parse object and and resolve symbols again before we check remaining
596	596	// undefined symbols.
597	597	const object_file_index = @intCast(u16, self.objects.items.len);
598		const object = try self.objects.addOne(self.base.allocator);
599		object.* = try archive.parseObject(self.base.allocator, offset.items[0]);
	598	var object = try archive.parseObject(self.base.allocator, offset.items[0]);
	599	try self.objects.append(self.base.allocator, object);
600	600	try self.resolveSymbolsInObject(object_file_index);
601	601
602	602	// continue loop for any remaining undefined symbols that still exist
...	...	@@ -860,7 +860,8 @@ fn getGlobalType(self: *const Wasm, loc: SymbolLoc) wasm.GlobalType {
860	860	if (is_undefined) {
861	861	return obj.findImport(.global, symbol.index).kind.global;
862	862	}
863		return obj.globals[symbol.index].global_type;
	863	const import_global_count = obj.importedCountByKind(.global);
	864	return obj.globals[symbol.index - import_global_count].global_type;
864	865	}
865	866	if (is_undefined) {
866	867	return self.imports.get(loc).?.kind.global;
...	...	@@ -880,7 +881,9 @@ fn getFunctionSignature(self: *const Wasm, loc: SymbolLoc) wasm.Type {
880	881	const ty_index = obj.findImport(.function, symbol.index).kind.function;
881	882	return obj.func_types[ty_index];
882	883	}
883		return obj.func_types[obj.functions[symbol.index].type_index];
	884	const import_function_count = obj.importedCountByKind(.function);
	885	const type_index = obj.functions[symbol.index - import_function_count].type_index;
	886	return obj.func_types[type_index];
884	887	}
885	888	if (is_undefined) {
886	889	const ty_index = self.imports.get(loc).?.kind.function;

src/link/Wasm/Archive.zig+2-1

...	...	@@ -218,6 +218,7 @@ pub fn parseObject(archive: Archive, allocator: Allocator, file_offset: u32) !Ob
218	218	const object_file = try std.fs.cwd().openFile(archive.name, .{});
219	219	errdefer object_file.close();
220	220
	221	const object_file_size = try header.size();
221	222	try object_file.seekTo(current_offset);
222		return Object.create(allocator, object_file, name);
	223	return Object.create(allocator, object_file, name, object_file_size);
223	224	}

src/link/Wasm/Object.zig+21-2

...	...	@@ -105,14 +105,33 @@ pub const InitError = error{NotObjectFile} \|\| ParseError \|\| std.fs.File.ReadErro
105	105
106	106	/// Initializes a new `Object` from a wasm object file.
107	107	/// This also parses and verifies the object file.
108		pub fn create(gpa: Allocator, file: std.fs.File, name: []const u8) InitError!Object {
	108	/// When a max size is given, will only parse up to the given size,
	109	/// else will read until the end of the file.
	110	pub fn create(gpa: Allocator, file: std.fs.File, name: []const u8, maybe_max_size: ?usize) InitError!Object {
109	111	var object: Object = .{
110	112	.file = file,
111	113	.name = try gpa.dupe(u8, name),
112	114	};
113	115
114	116	var is_object_file: bool = false;
115		try object.parse(gpa, file.reader(), &is_object_file);
	117	const size = maybe_max_size orelse size: {
	118	errdefer gpa.free(object.name);
	119	const stat = try file.stat();
	120	break :size @intCast(usize, stat.size);
	121	};
	122
	123	const file_contents = try gpa.alloc(u8, size);
	124	defer gpa.free(file_contents);
	125	var file_reader = file.reader();
	126	var read: usize = 0;
	127	while (read < size) {
	128	const n = try file_reader.read(file_contents[read..]);
	129	std.debug.assert(n != 0);
	130	read += n;
	131	}
	132	var fbs = std.io.fixedBufferStream(file_contents);
	133
	134	try object.parse(gpa, fbs.reader(), &is_object_file);
116	135	errdefer object.deinit(gpa);
117	136	if (!is_object_file) return error.NotObjectFile;
118	137