Merge pull request #14453 from ziglang/self-hosted-codegen-cleanup

self-hosted: cleanup codegen.Result
2023-01-26 08:01:51 +01:00
parent 96a55f6ce8 a95d58caf2
commit 48f9e491cb
12 changed files with 121 additions and 211 deletions
--- a/src/arch/aarch64/CodeGen.zig
+++ b/src/arch/aarch64/CodeGen.zig
@@ -24,7 +24,7 @@ const log = std.log.scoped(.codegen);
 const build_options = @import("build_options");

 const GenerateSymbolError = codegen.GenerateSymbolError;
-const FnResult = codegen.FnResult;
+const Result = codegen.Result;
 const DebugInfoOutput = codegen.DebugInfoOutput;

 const bits = @import("bits.zig");
@@ -349,7 +349,7 @@ pub fn generate(
    liveness: Liveness,
    code: *std.ArrayList(u8),
    debug_output: DebugInfoOutput,
-) GenerateSymbolError!FnResult {
+) GenerateSymbolError!Result {
    if (build_options.skip_non_native and builtin.cpu.arch != bin_file.options.target.cpu.arch) {
        @panic("Attempted to compile for architecture that was disabled by build configuration");
    }
@@ -392,8 +392,8 @@ pub fn generate(
    defer function.dbg_info_relocs.deinit(bin_file.allocator);

    var call_info = function.resolveCallingConventionValues(fn_type) catch |err| switch (err) {
-        error.CodegenFail => return FnResult{ .fail = function.err_msg.? },
-        error.OutOfRegisters => return FnResult{
+        error.CodegenFail => return Result{ .fail = function.err_msg.? },
+        error.OutOfRegisters => return Result{
            .fail = try ErrorMsg.create(bin_file.allocator, src_loc, "CodeGen ran out of registers. This is a bug in the Zig compiler.", .{}),
        },
        else => |e| return e,
@@ -406,8 +406,8 @@ pub fn generate(
    function.max_end_stack = call_info.stack_byte_count;

    function.gen() catch |err| switch (err) {
-        error.CodegenFail => return FnResult{ .fail = function.err_msg.? },
-        error.OutOfRegisters => return FnResult{
+        error.CodegenFail => return Result{ .fail = function.err_msg.? },
+        error.OutOfRegisters => return Result{
            .fail = try ErrorMsg.create(bin_file.allocator, src_loc, "CodeGen ran out of registers. This is a bug in the Zig compiler.", .{}),
        },
        else => |e| return e,
@@ -439,14 +439,14 @@ pub fn generate(
    defer emit.deinit();

    emit.emitMir() catch |err| switch (err) {
-        error.EmitFail => return FnResult{ .fail = emit.err_msg.? },
+        error.EmitFail => return Result{ .fail = emit.err_msg.? },
        else => |e| return e,
    };

    if (function.err_msg) |em| {
-        return FnResult{ .fail = em };
+        return Result{ .fail = em };
    } else {
-        return FnResult{ .appended = {} };
+        return Result.ok;
    }
 }

--- a/src/arch/arm/CodeGen.zig
+++ b/src/arch/arm/CodeGen.zig
@@ -23,7 +23,7 @@ const leb128 = std.leb;
 const log = std.log.scoped(.codegen);
 const build_options = @import("build_options");

-const FnResult = codegen.FnResult;
+const Result = codegen.Result;
 const GenerateSymbolError = codegen.GenerateSymbolError;
 const DebugInfoOutput = codegen.DebugInfoOutput;

@@ -356,7 +356,7 @@ pub fn generate(
    liveness: Liveness,
    code: *std.ArrayList(u8),
    debug_output: DebugInfoOutput,
-) GenerateSymbolError!FnResult {
+) GenerateSymbolError!Result {
    if (build_options.skip_non_native and builtin.cpu.arch != bin_file.options.target.cpu.arch) {
        @panic("Attempted to compile for architecture that was disabled by build configuration");
    }
@@ -399,8 +399,8 @@ pub fn generate(
    defer function.dbg_info_relocs.deinit(bin_file.allocator);

    var call_info = function.resolveCallingConventionValues(fn_type) catch |err| switch (err) {
-        error.CodegenFail => return FnResult{ .fail = function.err_msg.? },
-        error.OutOfRegisters => return FnResult{
+        error.CodegenFail => return Result{ .fail = function.err_msg.? },
+        error.OutOfRegisters => return Result{
            .fail = try ErrorMsg.create(bin_file.allocator, src_loc, "CodeGen ran out of registers. This is a bug in the Zig compiler.", .{}),
        },
        else => |e| return e,
@@ -413,8 +413,8 @@ pub fn generate(
    function.max_end_stack = call_info.stack_byte_count;

    function.gen() catch |err| switch (err) {
-        error.CodegenFail => return FnResult{ .fail = function.err_msg.? },
-        error.OutOfRegisters => return FnResult{
+        error.CodegenFail => return Result{ .fail = function.err_msg.? },
+        error.OutOfRegisters => return Result{
            .fail = try ErrorMsg.create(bin_file.allocator, src_loc, "CodeGen ran out of registers. This is a bug in the Zig compiler.", .{}),
        },
        else => |e| return e,
@@ -446,14 +446,14 @@ pub fn generate(
    defer emit.deinit();

    emit.emitMir() catch |err| switch (err) {
-        error.EmitFail => return FnResult{ .fail = emit.err_msg.? },
+        error.EmitFail => return Result{ .fail = emit.err_msg.? },
        else => |e| return e,
    };

    if (function.err_msg) |em| {
-        return FnResult{ .fail = em };
+        return Result{ .fail = em };
    } else {
-        return FnResult{ .appended = {} };
+        return Result.ok;
    }
 }

--- a/src/arch/riscv64/CodeGen.zig
+++ b/src/arch/riscv64/CodeGen.zig
@@ -22,7 +22,7 @@ const leb128 = std.leb;
 const log = std.log.scoped(.codegen);
 const build_options = @import("build_options");

-const FnResult = @import("../../codegen.zig").FnResult;
+const Result = @import("../../codegen.zig").Result;
 const GenerateSymbolError = @import("../../codegen.zig").GenerateSymbolError;
 const DebugInfoOutput = @import("../../codegen.zig").DebugInfoOutput;

@@ -225,7 +225,7 @@ pub fn generate(
    liveness: Liveness,
    code: *std.ArrayList(u8),
    debug_output: DebugInfoOutput,
-) GenerateSymbolError!FnResult {
+) GenerateSymbolError!Result {
    if (build_options.skip_non_native and builtin.cpu.arch != bin_file.options.target.cpu.arch) {
        @panic("Attempted to compile for architecture that was disabled by build configuration");
    }
@@ -268,8 +268,8 @@ pub fn generate(
    defer function.exitlude_jump_relocs.deinit(bin_file.allocator);

    var call_info = function.resolveCallingConventionValues(fn_type) catch |err| switch (err) {
-        error.CodegenFail => return FnResult{ .fail = function.err_msg.? },
-        error.OutOfRegisters => return FnResult{
+        error.CodegenFail => return Result{ .fail = function.err_msg.? },
+        error.OutOfRegisters => return Result{
            .fail = try ErrorMsg.create(bin_file.allocator, src_loc, "CodeGen ran out of registers. This is a bug in the Zig compiler.", .{}),
        },
        else => |e| return e,
@@ -282,8 +282,8 @@ pub fn generate(
    function.max_end_stack = call_info.stack_byte_count;

    function.gen() catch |err| switch (err) {
-        error.CodegenFail => return FnResult{ .fail = function.err_msg.? },
-        error.OutOfRegisters => return FnResult{
+        error.CodegenFail => return Result{ .fail = function.err_msg.? },
+        error.OutOfRegisters => return Result{
            .fail = try ErrorMsg.create(bin_file.allocator, src_loc, "CodeGen ran out of registers. This is a bug in the Zig compiler.", .{}),
        },
        else => |e| return e,
@@ -309,14 +309,14 @@ pub fn generate(
    defer emit.deinit();

    emit.emitMir() catch |err| switch (err) {
-        error.EmitFail => return FnResult{ .fail = emit.err_msg.? },
+        error.EmitFail => return Result{ .fail = emit.err_msg.? },
        else => |e| return e,
    };

    if (function.err_msg) |em| {
-        return FnResult{ .fail = em };
+        return Result{ .fail = em };
    } else {
-        return FnResult{ .appended = {} };
+        return Result.ok;
    }
 }

--- a/src/arch/sparc64/CodeGen.zig
+++ b/src/arch/sparc64/CodeGen.zig
@@ -20,7 +20,7 @@ const Emit = @import("Emit.zig");
 const Liveness = @import("../../Liveness.zig");
 const Type = @import("../../type.zig").Type;
 const GenerateSymbolError = @import("../../codegen.zig").GenerateSymbolError;
-const FnResult = @import("../../codegen.zig").FnResult;
+const Result = @import("../../codegen.zig").Result;
 const DebugInfoOutput = @import("../../codegen.zig").DebugInfoOutput;

 const build_options = @import("build_options");
@@ -265,7 +265,7 @@ pub fn generate(
    liveness: Liveness,
    code: *std.ArrayList(u8),
    debug_output: DebugInfoOutput,
-) GenerateSymbolError!FnResult {
+) GenerateSymbolError!Result {
    if (build_options.skip_non_native and builtin.cpu.arch != bin_file.options.target.cpu.arch) {
        @panic("Attempted to compile for architecture that was disabled by build configuration");
    }
@@ -310,8 +310,8 @@ pub fn generate(
    defer function.exitlude_jump_relocs.deinit(bin_file.allocator);

    var call_info = function.resolveCallingConventionValues(fn_type, .callee) catch |err| switch (err) {
-        error.CodegenFail => return FnResult{ .fail = function.err_msg.? },
-        error.OutOfRegisters => return FnResult{
+        error.CodegenFail => return Result{ .fail = function.err_msg.? },
+        error.OutOfRegisters => return Result{
            .fail = try ErrorMsg.create(bin_file.allocator, src_loc, "CodeGen ran out of registers. This is a bug in the Zig compiler.", .{}),
        },
        else => |e| return e,
@@ -324,8 +324,8 @@ pub fn generate(
    function.max_end_stack = call_info.stack_byte_count;

    function.gen() catch |err| switch (err) {
-        error.CodegenFail => return FnResult{ .fail = function.err_msg.? },
-        error.OutOfRegisters => return FnResult{
+        error.CodegenFail => return Result{ .fail = function.err_msg.? },
+        error.OutOfRegisters => return Result{
            .fail = try ErrorMsg.create(bin_file.allocator, src_loc, "CodeGen ran out of registers. This is a bug in the Zig compiler.", .{}),
        },
        else => |e| return e,
@@ -351,14 +351,14 @@ pub fn generate(
    defer emit.deinit();

    emit.emitMir() catch |err| switch (err) {
-        error.EmitFail => return FnResult{ .fail = emit.err_msg.? },
+        error.EmitFail => return Result{ .fail = emit.err_msg.? },
        else => |e| return e,
    };

    if (function.err_msg) |em| {
-        return FnResult{ .fail = em };
+        return Result{ .fail = em };
    } else {
-        return FnResult{ .appended = {} };
+        return Result.ok;
    }
 }

--- a/src/arch/wasm/CodeGen.zig
+++ b/src/arch/wasm/CodeGen.zig
@@ -627,13 +627,6 @@ test "Wasm - buildOpcode" {
    try testing.expectEqual(@as(wasm.Opcode, .f64_reinterpret_i64), f64_reinterpret_i64);
 }

-pub const Result = union(enum) {
-    /// The codegen bytes have been appended to `Context.code`
-    appended: void,
-    /// The data is managed externally and are part of the `Result`
-    externally_managed: []const u8,
-};
-
 /// Hashmap to store generated `WValue` for each `Air.Inst.Ref`
 pub const ValueTable = std.AutoArrayHashMapUnmanaged(Air.Inst.Ref, WValue);

@@ -1171,7 +1164,7 @@ pub fn generate(
    liveness: Liveness,
    code: *std.ArrayList(u8),
    debug_output: codegen.DebugInfoOutput,
-) codegen.GenerateSymbolError!codegen.FnResult {
+) codegen.GenerateSymbolError!codegen.Result {
    _ = src_loc;
    var code_gen: CodeGen = .{
        .gpa = bin_file.allocator,
@@ -1190,11 +1183,11 @@ pub fn generate(
    defer code_gen.deinit();

    genFunc(&code_gen) catch |err| switch (err) {
-        error.CodegenFail => return codegen.FnResult{ .fail = code_gen.err_msg },
+        error.CodegenFail => return codegen.Result{ .fail = code_gen.err_msg },
        else => |e| return e,
    };

-    return codegen.FnResult{ .appended = {} };
+    return codegen.Result.ok;
 }

 fn genFunc(func: *CodeGen) InnerError!void {
--- a/src/arch/x86_64/CodeGen.zig
+++ b/src/arch/x86_64/CodeGen.zig
@@ -16,7 +16,7 @@ const Compilation = @import("../../Compilation.zig");
 const DebugInfoOutput = codegen.DebugInfoOutput;
 const DW = std.dwarf;
 const ErrorMsg = Module.ErrorMsg;
-const FnResult = codegen.FnResult;
+const Result = codegen.Result;
 const GenerateSymbolError = codegen.GenerateSymbolError;
 const Emit = @import("Emit.zig");
 const Liveness = @import("../../Liveness.zig");
@@ -257,7 +257,7 @@ pub fn generate(
    liveness: Liveness,
    code: *std.ArrayList(u8),
    debug_output: DebugInfoOutput,
-) GenerateSymbolError!FnResult {
+) GenerateSymbolError!Result {
    if (build_options.skip_non_native and builtin.cpu.arch != bin_file.options.target.cpu.arch) {
        @panic("Attempted to compile for architecture that was disabled by build configuration");
    }
@@ -305,8 +305,8 @@ pub fn generate(
    defer if (builtin.mode == .Debug) function.mir_to_air_map.deinit();

    var call_info = function.resolveCallingConventionValues(fn_type) catch |err| switch (err) {
-        error.CodegenFail => return FnResult{ .fail = function.err_msg.? },
-        error.OutOfRegisters => return FnResult{
+        error.CodegenFail => return Result{ .fail = function.err_msg.? },
+        error.OutOfRegisters => return Result{
            .fail = try ErrorMsg.create(bin_file.allocator, src_loc, "CodeGen ran out of registers. This is a bug in the Zig compiler.", .{}),
        },
        else => |e| return e,
@@ -319,8 +319,8 @@ pub fn generate(
    function.max_end_stack = call_info.stack_byte_count;

    function.gen() catch |err| switch (err) {
-        error.CodegenFail => return FnResult{ .fail = function.err_msg.? },
-        error.OutOfRegisters => return FnResult{
+        error.CodegenFail => return Result{ .fail = function.err_msg.? },
+        error.OutOfRegisters => return Result{
            .fail = try ErrorMsg.create(bin_file.allocator, src_loc, "CodeGen ran out of registers. This is a bug in the Zig compiler.", .{}),
        },
        else => |e| return e,
@@ -345,14 +345,14 @@ pub fn generate(
    };
    defer emit.deinit();
    emit.lowerMir() catch |err| switch (err) {
-        error.EmitFail => return FnResult{ .fail = emit.err_msg.? },
+        error.EmitFail => return Result{ .fail = emit.err_msg.? },
        else => |e| return e,
    };

    if (function.err_msg) |em| {
-        return FnResult{ .fail = em };
+        return Result{ .fail = em };
    } else {
-        return FnResult{ .appended = {} };
+        return Result.ok;
    }
 }

--- a/src/codegen.zig
+++ b/src/codegen.zig
@@ -21,16 +21,11 @@ const TypedValue = @import("TypedValue.zig");
 const Value = @import("value.zig").Value;
 const Zir = @import("Zir.zig");

-pub const FnResult = union(enum) {
-    /// The `code` parameter passed to `generateSymbol` has the value appended.
-    appended: void,
-    fail: *ErrorMsg,
-};
 pub const Result = union(enum) {
-    /// The `code` parameter passed to `generateSymbol` has the value appended.
-    appended: void,
-    /// The value is available externally, `code` is unused.
-    externally_managed: []const u8,
+    /// The `code` parameter passed to `generateSymbol` has the value ok.
+    ok: void,
+
+    /// There was a codegen error.
    fail: *ErrorMsg,
 };

@@ -89,7 +84,7 @@ pub fn generateFunction(
    liveness: Liveness,
    code: *std.ArrayList(u8),
    debug_output: DebugInfoOutput,
-) GenerateSymbolError!FnResult {
+) GenerateSymbolError!Result {
    switch (bin_file.options.target.cpu.arch) {
        .arm,
        .armeb,
@@ -145,7 +140,7 @@ pub fn generateSymbol(
    if (typed_value.val.isUndefDeep()) {
        const abi_size = math.cast(usize, typed_value.ty.abiSize(target)) orelse return error.Overflow;
        try code.appendNTimes(0xaa, abi_size);
-        return Result{ .appended = {} };
+        return Result.ok;
    }

    switch (typed_value.ty.zigTypeTag()) {
@@ -176,7 +171,7 @@ pub fn generateSymbol(
                128 => writeFloat(f128, typed_value.val.toFloat(f128), target, endian, try code.addManyAsArray(16)),
                else => unreachable,
            }
-            return Result{ .appended = {} };
+            return Result.ok;
        },
        .Array => switch (typed_value.val.tag()) {
            .bytes => {
@@ -185,7 +180,7 @@ pub fn generateSymbol(
                // The bytes payload already includes the sentinel, if any
                try code.ensureUnusedCapacity(len);
                code.appendSliceAssumeCapacity(bytes[0..len]);
-                return Result{ .appended = {} };
+                return Result.ok;
            },
            .str_lit => {
                const str_lit = typed_value.val.castTag(.str_lit).?.data;
@@ -197,7 +192,7 @@ pub fn generateSymbol(
                    const byte = @intCast(u8, sent_val.toUnsignedInt(target));
                    code.appendAssumeCapacity(byte);
                }
-                return Result{ .appended = {} };
+                return Result.ok;
            },
            .aggregate => {
                const elem_vals = typed_value.val.castTag(.aggregate).?.data;
@@ -208,14 +203,11 @@ pub fn generateSymbol(
                        .ty = elem_ty,
                        .val = elem_val,
                    }, code, debug_output, reloc_info)) {
-                        .appended => {},
-                        .externally_managed => |slice| {
-                            code.appendSliceAssumeCapacity(slice);
-                        },
+                        .ok => {},
                        .fail => |em| return Result{ .fail = em },
                    }
                }
-                return Result{ .appended = {} };
+                return Result.ok;
            },
            .repeated => {
                const array = typed_value.val.castTag(.repeated).?.data;
@@ -229,10 +221,7 @@ pub fn generateSymbol(
                        .ty = elem_ty,
                        .val = array,
                    }, code, debug_output, reloc_info)) {
-                        .appended => {},
-                        .externally_managed => |slice| {
-                            code.appendSliceAssumeCapacity(slice);
-                        },
+                        .ok => {},
                        .fail => |em| return Result{ .fail = em },
                    }
                }
@@ -242,15 +231,12 @@ pub fn generateSymbol(
                        .ty = elem_ty,
                        .val = sentinel_val,
                    }, code, debug_output, reloc_info)) {
-                        .appended => {},
-                        .externally_managed => |slice| {
-                            code.appendSliceAssumeCapacity(slice);
-                        },
+                        .ok => {},
                        .fail => |em| return Result{ .fail = em },
                    }
                }

-                return Result{ .appended = {} };
+                return Result.ok;
            },
            .empty_array_sentinel => {
                const elem_ty = typed_value.ty.childType();
@@ -259,13 +245,10 @@ pub fn generateSymbol(
                    .ty = elem_ty,
                    .val = sentinel_val,
                }, code, debug_output, reloc_info)) {
-                    .appended => {},
-                    .externally_managed => |slice| {
-                        code.appendSliceAssumeCapacity(slice);
-                    },
+                    .ok => {},
                    .fail => |em| return Result{ .fail = em },
                }
-                return Result{ .appended = {} };
+                return Result.ok;
            },
            else => return Result{
                .fail = try ErrorMsg.create(
@@ -289,7 +272,7 @@ pub fn generateSymbol(
                    },
                    else => unreachable,
                }
-                return Result{ .appended = {} };
+                return Result.ok;
            },
            .variable => {
                const decl = typed_value.val.castTag(.variable).?.data.owner_decl;
@@ -309,10 +292,7 @@ pub fn generateSymbol(
                    .ty = slice_ptr_field_type,
                    .val = slice.ptr,
                }, code, debug_output, reloc_info)) {
-                    .appended => {},
-                    .externally_managed => |external_slice| {
-                        code.appendSliceAssumeCapacity(external_slice);
-                    },
+                    .ok => {},
                    .fail => |em| return Result{ .fail = em },
                }

@@ -321,14 +301,11 @@ pub fn generateSymbol(
                    .ty = Type.initTag(.usize),
                    .val = slice.len,
                }, code, debug_output, reloc_info)) {
-                    .appended => {},
-                    .externally_managed => |external_slice| {
-                        code.appendSliceAssumeCapacity(external_slice);
-                    },
+                    .ok => {},
                    .fail => |em| return Result{ .fail = em },
                }

-                return Result{ .appended = {} };
+                return Result.ok;
            },
            .field_ptr => {
                const field_ptr = typed_value.val.castTag(.field_ptr).?.data;
@@ -375,13 +352,10 @@ pub fn generateSymbol(
                            .ty = typed_value.ty,
                            .val = container_ptr,
                        }, code, debug_output, reloc_info)) {
-                            .appended => {},
-                            .externally_managed => |external_slice| {
-                                code.appendSliceAssumeCapacity(external_slice);
-                            },
+                            .ok => {},
                            .fail => |em| return Result{ .fail = em },
                        }
-                        return Result{ .appended = {} };
+                        return Result.ok;
                    },
                    else => return Result{
                        .fail = try ErrorMsg.create(
@@ -434,7 +408,7 @@ pub fn generateSymbol(
                    .signed => @bitCast(u8, @intCast(i8, typed_value.val.toSignedInt(target))),
                };
                try code.append(x);
-                return Result{ .appended = {} };
+                return Result.ok;
            }
            if (info.bits > 64) {
                var bigint_buffer: Value.BigIntSpace = undefined;
@@ -443,7 +417,7 @@ pub fn generateSymbol(
                const start = code.items.len;
                try code.resize(start + abi_size);
                bigint.writeTwosComplement(code.items[start..][0..abi_size], endian);
-                return Result{ .appended = {} };
+                return Result.ok;
            }
            switch (info.signedness) {
                .unsigned => {
@@ -471,7 +445,7 @@ pub fn generateSymbol(
                    }
                },
            }
-            return Result{ .appended = {} };
+            return Result.ok;
        },
        .Enum => {
            var int_buffer: Value.Payload.U64 = undefined;
@@ -481,7 +455,7 @@ pub fn generateSymbol(
            if (info.bits <= 8) {
                const x = @intCast(u8, int_val.toUnsignedInt(target));
                try code.append(x);
-                return Result{ .appended = {} };
+                return Result.ok;
            }
            if (info.bits > 64) {
                return Result{
@@ -519,12 +493,12 @@ pub fn generateSymbol(
                    }
                },
            }
-            return Result{ .appended = {} };
+            return Result.ok;
        },
        .Bool => {
            const x: u8 = @boolToInt(typed_value.val.toBool());
            try code.append(x);
-            return Result{ .appended = {} };
+            return Result.ok;
        },
        .Struct => {
            if (typed_value.ty.containerLayout() == .Packed) {
@@ -549,12 +523,7 @@ pub fn generateSymbol(
                            .ty = field_ty,
                            .val = field_val,
                        }, &tmp_list, debug_output, reloc_info)) {
-                            .appended => {
-                                mem.copy(u8, code.items[current_pos..], tmp_list.items);
-                            },
-                            .externally_managed => |external_slice| {
-                                mem.copy(u8, code.items[current_pos..], external_slice);
-                            },
+                            .ok => mem.copy(u8, code.items[current_pos..], tmp_list.items),
                            .fail => |em| return Result{ .fail = em },
                        }
                    } else {
@@ -563,7 +532,7 @@ pub fn generateSymbol(
                    bits += @intCast(u16, field_ty.bitSize(target));
                }

-                return Result{ .appended = {} };
+                return Result.ok;
            }

            const struct_begin = code.items.len;
@@ -576,10 +545,7 @@ pub fn generateSymbol(
                    .ty = field_ty,
                    .val = field_val,
                }, code, debug_output, reloc_info)) {
-                    .appended => {},
-                    .externally_managed => |external_slice| {
-                        code.appendSliceAssumeCapacity(external_slice);
-                    },
+                    .ok => {},
                    .fail => |em| return Result{ .fail = em },
                }
                const unpadded_field_end = code.items.len - struct_begin;
@@ -593,7 +559,7 @@ pub fn generateSymbol(
                }
            }

-            return Result{ .appended = {} };
+            return Result.ok;
        },
        .Union => {
            const union_obj = typed_value.val.castTag(.@"union").?.data;
@@ -612,10 +578,7 @@ pub fn generateSymbol(
                    .ty = typed_value.ty.unionTagType().?,
                    .val = union_obj.tag,
                }, code, debug_output, reloc_info)) {
-                    .appended => {},
-                    .externally_managed => |external_slice| {
-                        code.appendSliceAssumeCapacity(external_slice);
-                    },
+                    .ok => {},
                    .fail => |em| return Result{ .fail = em },
                }
            }
@@ -632,10 +595,7 @@ pub fn generateSymbol(
                    .ty = field_ty,
                    .val = union_obj.val,
                }, code, debug_output, reloc_info)) {
-                    .appended => {},
-                    .externally_managed => |external_slice| {
-                        code.appendSliceAssumeCapacity(external_slice);
-                    },
+                    .ok => {},
                    .fail => |em| return Result{ .fail = em },
                }

@@ -650,15 +610,12 @@ pub fn generateSymbol(
                    .ty = union_ty.tag_ty,
                    .val = union_obj.tag,
                }, code, debug_output, reloc_info)) {
-                    .appended => {},
-                    .externally_managed => |external_slice| {
-                        code.appendSliceAssumeCapacity(external_slice);
-                    },
+                    .ok => {},
                    .fail => |em| return Result{ .fail = em },
                }
            }

-            return Result{ .appended = {} };
+            return Result.ok;
        },
        .Optional => {
            var opt_buf: Type.Payload.ElemType = undefined;
@@ -669,7 +626,7 @@ pub fn generateSymbol(

            if (!payload_type.hasRuntimeBits()) {
                try code.writer().writeByteNTimes(@boolToInt(is_pl), abi_size);
-                return Result{ .appended = {} };
+                return Result.ok;
            }

            if (typed_value.ty.optionalReprIsPayload()) {
@@ -678,10 +635,7 @@ pub fn generateSymbol(
                        .ty = payload_type,
                        .val = payload.data,
                    }, code, debug_output, reloc_info)) {
-                        .appended => {},
-                        .externally_managed => |external_slice| {
-                            code.appendSliceAssumeCapacity(external_slice);
-                        },
+                        .ok => {},
                        .fail => |em| return Result{ .fail = em },
                    }
                } else if (!typed_value.val.isNull()) {
@@ -689,17 +643,14 @@ pub fn generateSymbol(
                        .ty = payload_type,
                        .val = typed_value.val,
                    }, code, debug_output, reloc_info)) {
-                        .appended => {},
-                        .externally_managed => |external_slice| {
-                            code.appendSliceAssumeCapacity(external_slice);
-                        },
+                        .ok => {},
                        .fail => |em| return Result{ .fail = em },
                    }
                } else {
                    try code.writer().writeByteNTimes(0, abi_size);
                }

-                return Result{ .appended = {} };
+                return Result.ok;
            }

            const value = if (typed_value.val.castTag(.opt_payload)) |payload| payload.data else Value.initTag(.undef);
@@ -708,14 +659,11 @@ pub fn generateSymbol(
                .ty = payload_type,
                .val = value,
            }, code, debug_output, reloc_info)) {
-                .appended => {},
-                .externally_managed => |external_slice| {
-                    code.appendSliceAssumeCapacity(external_slice);
-                },
+                .ok => {},
                .fail => |em| return Result{ .fail = em },
            }

-            return Result{ .appended = {} };
+            return Result.ok;
        },
        .ErrorUnion => {
            const error_ty = typed_value.ty.errorUnionSet();
@@ -740,10 +688,7 @@ pub fn generateSymbol(
                    .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);
-                    },
+                    .ok => {},
                    .fail => |em| return Result{ .fail = em },
                }
            }
@@ -756,10 +701,7 @@ pub fn generateSymbol(
                    .ty = payload_ty,
                    .val = payload_val,
                }, code, debug_output, reloc_info)) {
-                    .appended => {},
-                    .externally_managed => |external_slice| {
-                        code.appendSliceAssumeCapacity(external_slice);
-                    },
+                    .ok => {},
                    .fail => |em| return Result{ .fail = em },
                }
                const unpadded_end = code.items.len - begin;
@@ -778,10 +720,7 @@ pub fn generateSymbol(
                    .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);
-                    },
+                    .ok => {},
                    .fail => |em| return Result{ .fail = em },
                }
                const unpadded_end = code.items.len - begin;
@@ -793,7 +732,7 @@ pub fn generateSymbol(
                }
            }

-            return Result{ .appended = {} };
+            return Result.ok;
        },
        .ErrorSet => {
            switch (typed_value.val.tag()) {
@@ -806,7 +745,7 @@ pub fn generateSymbol(
                    try code.writer().writeByteNTimes(0, @intCast(usize, Type.anyerror.abiSize(target)));
                },
            }
-            return Result{ .appended = {} };
+            return Result.ok;
        },
        .Vector => switch (typed_value.val.tag()) {
            .bytes => {
@@ -814,7 +753,7 @@ pub fn generateSymbol(
                const len = @intCast(usize, typed_value.ty.arrayLen());
                try code.ensureUnusedCapacity(len);
                code.appendSliceAssumeCapacity(bytes[0..len]);
-                return Result{ .appended = {} };
+                return Result.ok;
            },
            .aggregate => {
                const elem_vals = typed_value.val.castTag(.aggregate).?.data;
@@ -825,14 +764,11 @@ pub fn generateSymbol(
                        .ty = elem_ty,
                        .val = elem_val,
                    }, code, debug_output, reloc_info)) {
-                        .appended => {},
-                        .externally_managed => |slice| {
-                            code.appendSliceAssumeCapacity(slice);
-                        },
+                        .ok => {},
                        .fail => |em| return Result{ .fail = em },
                    }
                }
-                return Result{ .appended = {} };
+                return Result.ok;
            },
            .repeated => {
                const array = typed_value.val.castTag(.repeated).?.data;
@@ -845,14 +781,11 @@ pub fn generateSymbol(
                        .ty = elem_ty,
                        .val = array,
                    }, code, debug_output, reloc_info)) {
-                        .appended => {},
-                        .externally_managed => |slice| {
-                            code.appendSliceAssumeCapacity(slice);
-                        },
+                        .ok => {},
                        .fail => |em| return Result{ .fail = em },
                    }
                }
-                return Result{ .appended = {} };
+                return Result.ok;
            },
            .str_lit => {
                const str_lit = typed_value.val.castTag(.str_lit).?.data;
@@ -860,7 +793,7 @@ pub fn generateSymbol(
                const bytes = mod.string_literal_bytes.items[str_lit.index..][0..str_lit.len];
                try code.ensureUnusedCapacity(str_lit.len);
                code.appendSliceAssumeCapacity(bytes);
-                return Result{ .appended = {} };
+                return Result.ok;
            },
            else => unreachable,
        },
@@ -901,10 +834,7 @@ fn lowerDeclRef(
            .ty = slice_ptr_field_type,
            .val = typed_value.val,
        }, code, debug_output, reloc_info)) {
-            .appended => {},
-            .externally_managed => |external_slice| {
-                code.appendSliceAssumeCapacity(external_slice);
-            },
+            .ok => {},
            .fail => |em| return Result{ .fail = em },
        }

@@ -917,14 +847,11 @@ fn lowerDeclRef(
            .ty = Type.usize,
            .val = Value.initPayload(&slice_len.base),
        }, code, debug_output, reloc_info)) {
-            .appended => {},
-            .externally_managed => |external_slice| {
-                code.appendSliceAssumeCapacity(external_slice);
-            },
+            .ok => {},
            .fail => |em| return Result{ .fail = em },
        }

-        return Result{ .appended = {} };
+        return Result.ok;
    }

    const ptr_width = target.cpu.arch.ptrBitWidth();
@@ -932,7 +859,7 @@ fn lowerDeclRef(
    const is_fn_body = decl.ty.zigTypeTag() == .Fn;
    if (!is_fn_body and !decl.ty.hasRuntimeBits()) {
        try code.writer().writeByteNTimes(0xaa, @divExact(ptr_width, 8));
-        return Result{ .appended = {} };
+        return Result.ok;
    }

    module.markDeclAlive(decl);
@@ -950,7 +877,7 @@ fn lowerDeclRef(
        else => unreachable,
    }

-    return Result{ .appended = {} };
+    return Result.ok;
 }

 pub fn errUnionPayloadOffset(payload_ty: Type, target: std.Target) u64 {
--- a/src/link/Coff.zig
+++ b/src/link/Coff.zig
@@ -928,7 +928,7 @@ pub fn updateFunc(self: *Coff, module: *Module, func: *Module.Fn, air: Air, live
        .none,
    );
    const code = switch (res) {
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try module.failed_decls.put(module.gpa, decl_index, em);
@@ -981,8 +981,7 @@ pub fn lowerUnnamedConst(self: *Coff, tv: TypedValue, decl_index: Module.Decl.In
        .parent_atom_index = atom.sym_index,
    });
    const code = switch (res) {
-        .externally_managed => |x| x,
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try mod.failed_decls.put(mod.gpa, decl_index, em);
@@ -1042,8 +1041,7 @@ pub fn updateDecl(self: *Coff, module: *Module, decl_index: Module.Decl.Index) !
        .parent_atom_index = decl.link.coff.sym_index,
    });
    const code = switch (res) {
-        .externally_managed => |x| x,
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try module.failed_decls.put(module.gpa, decl_index, em);
--- a/src/link/Elf.zig
+++ b/src/link/Elf.zig
@@ -2479,7 +2479,7 @@ pub fn updateFunc(self: *Elf, module: *Module, func: *Module.Fn, air: Air, liven
        try codegen.generateFunction(&self.base, decl.srcLoc(), func, air, liveness, &code_buffer, .none);

    const code = switch (res) {
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try module.failed_decls.put(module.gpa, decl_index, em);
@@ -2553,8 +2553,7 @@ pub fn updateDecl(self: *Elf, module: *Module, decl_index: Module.Decl.Index) !v
        });

    const code = switch (res) {
-        .externally_managed => |x| x,
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try module.failed_decls.put(module.gpa, decl_index, em);
@@ -2618,8 +2617,7 @@ pub fn lowerUnnamedConst(self: *Elf, typed_value: TypedValue, decl_index: Module
        .parent_atom_index = atom.local_sym_index,
    });
    const code = switch (res) {
-        .externally_managed => |x| x,
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try mod.failed_decls.put(mod.gpa, decl_index, em);
--- a/src/link/MachO.zig
+++ b/src/link/MachO.zig
@@ -2017,7 +2017,7 @@ pub fn updateFunc(self: *MachO, module: *Module, func: *Module.Fn, air: Air, liv
        try codegen.generateFunction(&self.base, decl.srcLoc(), func, air, liveness, &code_buffer, .none);

    const code = switch (res) {
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try module.failed_decls.put(module.gpa, decl_index, em);
@@ -2082,8 +2082,7 @@ pub fn lowerUnnamedConst(self: *MachO, typed_value: TypedValue, decl_index: Modu
        .parent_atom_index = atom.sym_index,
    });
    const code = switch (res) {
-        .externally_managed => |x| x,
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try module.failed_decls.put(module.gpa, decl_index, em);
@@ -2167,8 +2166,7 @@ pub fn updateDecl(self: *MachO, module: *Module, decl_index: Module.Decl.Index)
        });

    const code = switch (res) {
-        .externally_managed => |x| x,
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try module.failed_decls.put(module.gpa, decl_index, em);
--- a/src/link/Plan9.zig
+++ b/src/link/Plan9.zig
@@ -299,7 +299,7 @@ pub fn updateFunc(self: *Plan9, module: *Module, func: *Module.Fn, air: Air, liv
        },
    );
    const code = switch (res) {
-        .appended => try code_buffer.toOwnedSlice(),
+        .ok => try code_buffer.toOwnedSlice(),
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try module.failed_decls.put(module.gpa, decl_index, em);
@@ -358,8 +358,7 @@ pub fn lowerUnnamedConst(self: *Plan9, tv: TypedValue, decl_index: Module.Decl.I
        .parent_atom_index = @enumToInt(decl_index),
    });
    const code = switch (res) {
-        .externally_managed => |x| x,
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try mod.failed_decls.put(mod.gpa, decl_index, em);
@@ -403,8 +402,7 @@ pub fn updateDecl(self: *Plan9, module: *Module, decl_index: Module.Decl.Index)
        .parent_atom_index = @enumToInt(decl_index),
    });
    const code = switch (res) {
-        .externally_managed => |x| x,
-        .appended => code_buffer.items,
+        .ok => code_buffer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try module.failed_decls.put(module.gpa, decl_index, em);
--- a/src/link/Wasm.zig
+++ b/src/link/Wasm.zig
@@ -1046,7 +1046,7 @@ pub fn updateFunc(wasm: *Wasm, mod: *Module, func: *Module.Fn, air: Air, livenes
    );

    const code = switch (result) {
-        .appended => code_writer.items,
+        .ok => code_writer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try mod.failed_decls.put(mod.gpa, decl_index, em);
@@ -1113,8 +1113,7 @@ pub fn updateDecl(wasm: *Wasm, mod: *Module, decl_index: Module.Decl.Index) !voi
    );

    const code = switch (res) {
-        .externally_managed => |x| x,
-        .appended => code_writer.items,
+        .ok => code_writer.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try mod.failed_decls.put(mod.gpa, decl_index, em);
@@ -1250,8 +1249,7 @@ pub fn lowerUnnamedConst(wasm: *Wasm, tv: TypedValue, decl_index: Module.Decl.In
        },
    );
    const code = switch (result) {
-        .externally_managed => |x| x,
-        .appended => value_bytes.items,
+        .ok => value_bytes.items,
        .fail => |em| {
            decl.analysis = .codegen_failure;
            try mod.failed_decls.put(mod.gpa, decl_index, em);