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WebAssembly: don't append --export for functions

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No longer automatically append the `--export` flag for each exported
function unconditionally. This was essentially a hack to prevent
binary bloat caused by compiler-rt symbols being always included in
the final binary as they were exported and therefore not garbage-
collected. This is no longer needed as we now support the ability to
set the visibility of exports.
This essentially reverts 6d951aff7e
This commit is contained in:
Luuk de Gram
2022-12-28 14:41:27 +01:00
parent 7802c26449
commit 4aab8118a7
2 changed files with 6 additions and 34 deletions
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9
src/Compilation.zig
View File

@@ -181,10 +181,6 @@ emit_docs: ?EmitLoc,
work_queue_wait_group: WaitGroup = .{},
astgen_wait_group: WaitGroup = .{},
/// Exported symbol names. This is only for when the target is wasm.
/// TODO: Remove this when Stage2 becomes the default compiler as it will already have this information.
export_symbol_names: std.ArrayListUnmanaged([]const u8) = .{},
pub const default_stack_protector_buffer_size = 4;
pub const SemaError = Module.SemaError;
@@ -2168,11 +2164,6 @@ pub fn destroy(self: *Compilation) void {
self.cache_parent.manifest_dir.close();
if (self.owned_link_dir) |*dir| dir.close();
for (self.export_symbol_names.items) |symbol_name| {
gpa.free(symbol_name);
}
self.export_symbol_names.deinit(gpa);
// This destroys `self`.
self.arena_state.promote(gpa).deinit();
}

31
src/link/Wasm.zig
View File

@@ -3406,39 +3406,14 @@ fn linkWithLLD(wasm: *Wasm, comp: *Compilation, prog_node: *std.Progress.Node) !
try argv.append("--stack-first");
}
var auto_export_symbols = true;
// Users are allowed to specify which symbols they want to export to the wasm host.
for (wasm.base.options.export_symbol_names) |symbol_name| {
const arg = try std.fmt.allocPrint(arena, "--export={s}", .{symbol_name});
try argv.append(arg);
auto_export_symbols = false;
}
if (wasm.base.options.rdynamic) {
try argv.append("--export-dynamic");
auto_export_symbols = false;
}
if (auto_export_symbols) {
if (wasm.base.options.module) |mod| {
// when we use stage1, we use the exports that stage1 provided us.
// For stage2, we can directly retrieve them from the module.
const skip_export_non_fn = target.os.tag == .wasi and
wasm.base.options.wasi_exec_model == .command;
for (mod.decl_exports.values()) |exports| {
for (exports.items) |exprt| {
const exported_decl = mod.declPtr(exprt.exported_decl);
if (skip_export_non_fn and exported_decl.ty.zigTypeTag() != .Fn) {
// skip exporting symbols when we're building a WASI command
// and the symbol is not a function
continue;
}
const symbol_name = exported_decl.name;
const arg = try std.fmt.allocPrint(arena, "--export={s}", .{symbol_name});
try argv.append(arg);
}
}
}
}
if (wasm.base.options.entry) |entry| {
@@ -3457,6 +3432,12 @@ fn linkWithLLD(wasm: *Wasm, comp: *Compilation, prog_node: *std.Progress.Node) !
if (wasm.base.options.wasi_exec_model == .reactor) {
// Reactor execution model does not have _start so lld doesn't look for it.
try argv.append("--no-entry");
// Make sure "_initialize" and other used-defined functions are exported if this is WASI reactor.
// If rdynamic is true, it will already be appended, so only verify if the user did not specify
// the flag in which case, we ensure `--export-dynamic` is called.
if (!wasm.base.options.rdynamic) {
try argv.append("--export-dynamic");
}
}
} else if (wasm.base.options.entry == null) {
try argv.append("--no-entry"); // So lld doesn't look for _start.