commit 6069161a51c4672b37c87d8cda06999baf5fef2c (tree)
parent aebd84b525d8ea91f9be5b6562e1fe7abf749220
Author: Matthew Lugg <mlugg@mlugg.co.uk>
Date: Thu, 8 Jan 2026 13:55:46 +0000
link.Wasm: reserve sufficient capacity for `@tagName` function code
Resolves: https://codeberg.org/ziglang/zig/issues/30748
Diffstat:
3 files changed, 86 insertions(+), 67 deletions(-)
diff --git a/ci/loongarch64-linux-debug.sh b/ci/loongarch64-linux-debug.sh
@@ -48,7 +48,6 @@ stage3-debug/bin/zig build test docs \
--maxrss ${ZSF_MAX_RSS:-0} \
-Dstatic-llvm \
-Dskip-non-native \
- -Dskip-test-incremental \
-Dtarget=native-native-musl \
--search-prefix "$PREFIX" \
--zig-lib-dir "$PWD/../lib" \
diff --git a/ci/loongarch64-linux-release.sh b/ci/loongarch64-linux-release.sh
@@ -48,7 +48,6 @@ stage3-release/bin/zig build test docs \
--maxrss ${ZSF_MAX_RSS:-0} \
-Dstatic-llvm \
-Dskip-non-native \
- -Dskip-test-incremental \
-Dtarget=native-native-musl \
--search-prefix "$PREFIX" \
--zig-lib-dir "$PWD/../lib" \
diff --git a/src/link/Wasm/Flush.zig b/src/link/Wasm/Flush.zig
@@ -1871,13 +1871,21 @@ fn emitTagNameFunction(
const enum_type = ip.loadEnumType(enum_type_ip);
const tag_values = enum_type.values.get(ip);
- try code.ensureUnusedCapacity(gpa, 7 * 5 + 6 + 1 * 6);
- appendReservedUleb32(code, 0); // no locals
-
const slice_abi_size = 8;
const encoded_alignment = @ctz(@as(u32, 4));
+
if (tag_values.len == 0) {
- // Then it's auto-numbered and therefore a direct table lookup.
+ // Auto-numbered, therefore a direct table lookup.
+
+ try code.ensureUnusedCapacity(
+ gpa,
+ 6 * @sizeOf(std.wasm.Opcode) +
+ 7 * 5 + // appendReservedUleb32
+ 1 * 6, // appendReservedI32Const
+ );
+
+ appendReservedUleb32(code, 0); // no locals
+
code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.local_get));
appendReservedUleb32(code, 0);
@@ -1894,78 +1902,91 @@ fn emitTagNameFunction(
code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.i64_store));
appendReservedUleb32(code, encoded_alignment);
appendReservedUleb32(code, 0);
- } else {
- const int_info = Zcu.Type.intInfo(.fromInterned(enum_type.tag_ty), zcu);
- const outer_block_type: std.wasm.BlockType = switch (int_info.bits) {
- 0...32 => .i32,
- 33...64 => .i64,
- else => return diags.fail("wasm linker does not yet implement @tagName for sparse enums with more than 64 bit integer tag types", .{}),
- };
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.local_get));
- appendReservedUleb32(code, 0);
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.end));
- // Outer block that computes table offset.
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.block));
- code.appendAssumeCapacity(@intFromEnum(outer_block_type));
-
- for (tag_values, 0..) |tag_value, tag_index| {
- // block for this if case
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.block));
- code.appendAssumeCapacity(@intFromEnum(std.wasm.BlockType.empty));
-
- // Tag value whose name should be returned.
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.local_get));
- appendReservedUleb32(code, 1);
-
- const val: Zcu.Value = .fromInterned(tag_value);
- switch (outer_block_type) {
- .i32 => {
- const x: u32 = switch (int_info.signedness) {
- .signed => @bitCast(@as(i32, @intCast(val.toSignedInt(zcu)))),
- .unsigned => @intCast(val.toUnsignedInt(zcu)),
- };
- appendReservedI32Const(code, x);
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.i32_ne));
- },
- .i64 => {
- const x: u64 = switch (int_info.signedness) {
- .signed => @bitCast(val.toSignedInt(zcu)),
- .unsigned => val.toUnsignedInt(zcu),
- };
- appendReservedI64Const(code, x);
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.i64_ne));
- },
- else => unreachable,
- }
+ return;
+ }
- // if they're not equal, break out of current branch
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.br_if));
- appendReservedUleb32(code, 0);
+ const int_info = Zcu.Type.intInfo(.fromInterned(enum_type.tag_ty), zcu);
+ const outer_block_type: std.wasm.BlockType = switch (int_info.bits) {
+ 0...32 => .i32,
+ 33...64 => .i64,
+ else => return diags.fail("wasm linker does not yet implement @tagName for sparse enums with more than 64 bit integer tag types", .{}),
+ };
- // Put the table offset of the result on the stack.
- appendReservedI32Const(code, @intCast(tag_index * slice_abi_size));
+ try code.ensureUnusedCapacity(
+ gpa,
+ (7 + tag_values.len * 6) * @sizeOf(std.wasm.Opcode) +
+ (1 + tag_values.len * 1) * @sizeOf(std.wasm.BlockType) +
+ (6 + tag_values.len * 3) * 5 + // appendReservedUleb32
+ (tag_values.len * 2) * 11, // appendReservedI32Const / appendReservedI64Const
+ );
- // break outside blocks
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.br));
- appendReservedUleb32(code, 1);
+ appendReservedUleb32(code, 0); // no locals
- // end the block for this case
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.end));
- }
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.@"unreachable"));
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.end));
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.local_get));
+ appendReservedUleb32(code, 0);
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.i64_load));
- appendReservedUleb32(code, encoded_alignment);
- appendReservedUleb32(code, table_base_addr + table_index * 8);
+ // Outer block that computes table offset.
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.block));
+ code.appendAssumeCapacity(@intFromEnum(outer_block_type));
- code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.i64_store));
- appendReservedUleb32(code, encoded_alignment);
+ for (tag_values, 0..) |tag_value, tag_index| {
+ // block for this if case
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.block));
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.BlockType.empty));
+
+ // Tag value whose name should be returned.
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.local_get));
+ appendReservedUleb32(code, 1);
+
+ const val: Zcu.Value = .fromInterned(tag_value);
+ switch (outer_block_type) {
+ .i32 => {
+ const x: u32 = switch (int_info.signedness) {
+ .signed => @bitCast(@as(i32, @intCast(val.toSignedInt(zcu)))),
+ .unsigned => @intCast(val.toUnsignedInt(zcu)),
+ };
+ appendReservedI32Const(code, x);
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.i32_ne));
+ },
+ .i64 => {
+ const x: u64 = switch (int_info.signedness) {
+ .signed => @bitCast(val.toSignedInt(zcu)),
+ .unsigned => val.toUnsignedInt(zcu),
+ };
+ appendReservedI64Const(code, x);
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.i64_ne));
+ },
+ else => unreachable,
+ }
+
+ // if they're not equal, break out of current branch
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.br_if));
appendReservedUleb32(code, 0);
+
+ // Put the table offset of the result on the stack.
+ appendReservedI32Const(code, @intCast(tag_index * slice_abi_size));
+
+ // break outside blocks
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.br));
+ appendReservedUleb32(code, 1);
+
+ // end the block for this case
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.end));
}
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.@"unreachable"));
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.end));
+
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.i64_load));
+ appendReservedUleb32(code, encoded_alignment);
+ appendReservedUleb32(code, table_base_addr + table_index * 8);
+
+ code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.i64_store));
+ appendReservedUleb32(code, encoded_alignment);
+ appendReservedUleb32(code, 0);
- // End of the function body
code.appendAssumeCapacity(@intFromEnum(std.wasm.Opcode.end));
}
