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| author | Luuk de Gram <luuk@degram.dev> | 2022-05-23 18:24:03 +0200 |
|---|---|---|
| committer | Andrew Kelley <andrew@ziglang.org> | 2022-05-24 15:34:52 -0700 |
| commit | c90a97f9be9ffef858b0e450de5006f61a12fafd (patch) | |
| tree | c8ba955be7b7cd81230a2e0da39f2c36e73a681e | |
| parent | 3264abe3d8f658e1b7275d2be80e43eddfc098dc (diff) | |
| download | zig-c90a97f9be9ffef858b0e450de5006f61a12fafd.tar.gz zig-c90a97f9be9ffef858b0e450de5006f61a12fafd.zip | |
codegen: Order error union fields per alignment
Based on the size of the payload the native backends will lower
the error union with its fields (errorset & payload) in the correct order.
e.g. ErrorA!u8 will first lower the error set's value and then the payload.
In the event of ErrorA!u32 will lower the payload first.
| -rw-r--r-- | src/codegen.zig | 48 |
1 files changed, 41 insertions, 7 deletions
diff --git a/src/codegen.zig b/src/codegen.zig index bd556baa5e..81b303ab82 100644 --- a/src/codegen.zig +++ b/src/codegen.zig @@ -702,16 +702,50 @@ pub fn generateSymbol( .ErrorUnion => { const error_ty = typed_value.ty.errorUnionSet(); const payload_ty = typed_value.ty.errorUnionPayload(); + + if (error_ty.errorSetCardinality() == .zero) { + const payload_val = typed_value.val.castTag(.eu_payload).?.data; + return generateSymbol(bin_file, src_loc, .{ + .ty = payload_ty, + .val = payload_val, + }, code, debug_output, reloc_info); + } + const is_payload = typed_value.val.errorUnionIsPayload(); + if (!payload_ty.hasRuntimeBitsIgnoreComptime()) { + const err_val = if (!is_payload) typed_value.val else Value.initTag(.zero); + return generateSymbol(bin_file, src_loc, .{ + .ty = error_ty, + .val = err_val, + }, code, debug_output, reloc_info); + } + + const payload_align = payload_ty.abiAlignment(target); + const error_align = Type.anyerror.abiAlignment(target); const abi_align = typed_value.ty.abiAlignment(target); + // error value first when its type is larger than the error union's payload + if (error_align > payload_align) { + switch (try generateSymbol(bin_file, src_loc, .{ + .ty = error_ty, + .val = if (is_payload) Value.initTag(.zero) else typed_value.val, + }, code, debug_output, reloc_info)) { + .appended => {}, + .externally_managed => |external_slice| { + code.appendSliceAssumeCapacity(external_slice); + }, + .fail => |em| return Result{ .fail = em }, + } + } + + // emit payload part of the error union { - const error_val = if (!is_payload) typed_value.val else Value.initTag(.zero); const begin = code.items.len; + const payload_val = if (typed_value.val.castTag(.eu_payload)) |val| val.data else Value.initTag(.undef); switch (try generateSymbol(bin_file, src_loc, .{ - .ty = error_ty, - .val = error_val, + .ty = payload_ty, + .val = payload_val, }, code, debug_output, reloc_info)) { .appended => {}, .externally_managed => |external_slice| { @@ -728,12 +762,12 @@ pub fn generateSymbol( } } - if (payload_ty.hasRuntimeBits()) { + // Payload size is larger than error set, so emit our error set last + if (error_align < payload_align) { const begin = code.items.len; - const payload_val = if (typed_value.val.castTag(.eu_payload)) |val| val.data else Value.initTag(.undef); switch (try generateSymbol(bin_file, src_loc, .{ - .ty = payload_ty, - .val = payload_val, + .ty = error_ty, + .val = if (is_payload) Value.initTag(.zero) else typed_value.val, }, code, debug_output, reloc_info)) { .appended => {}, .externally_managed => |external_slice| { |