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AstGen: switch expressions properly handle result locations
This commit is contained in:
Andrew Kelley
parent
2a1dd174cd
commit
549af582e7
132
src/AstGen.zig
132
src/AstGen.zig
@ -2679,7 +2679,7 @@ fn switchExpr(
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const operand_ty_inst = try parent_gz.addUnNode(typeof_tag, operand, operand_node);
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const item_rl: ResultLoc = .{ .ty = operand_ty_inst };
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// Contains the data that goes into the `extra` array for the SwitchBr/SwitchBrMulti.
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// Contains the data that goes into the `extra` array for the SwitchBlock/SwitchBlockMulti.
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// This is the header as well as the optional else prong body, as well as all the
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// scalar cases.
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// At the end we will memcpy this into place.
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@ -2757,7 +2757,7 @@ fn switchExpr(
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if (!astgen.refIsNoReturn(case_result)) {
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_ = try case_scope.addBreak(.@"break", switch_block, case_result);
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}
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// Documentation for this: `zir.Inst.SwitchBr` and `zir.Inst.SwitchBrMulti`.
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// Documentation for this: `zir.Inst.SwitchBlock` and `zir.Inst.SwitchBlockMulti`.
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try scalar_cases_payload.ensureCapacity(gpa, scalar_cases_payload.items.len +
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3 + // operand, scalar_cases_len, else body len
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@boolToInt(multi_cases_len != 0) +
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@ -2770,7 +2770,7 @@ fn switchExpr(
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scalar_cases_payload.appendAssumeCapacity(@intCast(u32, case_scope.instructions.items.len));
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scalar_cases_payload.appendSliceAssumeCapacity(case_scope.instructions.items);
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} else {
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// Documentation for this: `zir.Inst.SwitchBr` and `zir.Inst.SwitchBrMulti`.
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// Documentation for this: `zir.Inst.SwitchBlock` and `zir.Inst.SwitchBlockMulti`.
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try scalar_cases_payload.ensureCapacity(gpa, scalar_cases_payload.items.len +
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2 + // operand, scalar_cases_len
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@boolToInt(multi_cases_len != 0));
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@ -2782,6 +2782,8 @@ fn switchExpr(
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}
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// In this pass we generate all the item and prong expressions except the special case.
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var multi_case_index: u32 = 0;
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var scalar_case_index: u32 = 0;
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for (case_nodes) |case_node| {
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if (case_node == special_node)
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continue;
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@ -2818,7 +2820,13 @@ fn switchExpr(
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0b10 => .switch_capture_multi,
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0b11 => .switch_capture_multi_ref,
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};
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const capture_index = if (is_multi_case) multi_cases_len else scalar_cases_len;
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const capture_index = if (is_multi_case) ci: {
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multi_case_index += 1;
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break :ci multi_case_index - 1;
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} else ci: {
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scalar_case_index += 1;
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break :ci scalar_case_index - 1;
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};
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const capture = try case_scope.add(.{
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.tag = capture_tag,
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.data = .{ .switch_capture = .{
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@ -2918,17 +2926,121 @@ fn switchExpr(
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else => unreachable,
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};
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const zir_datas = astgen.instructions.items(.data);
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zir_datas[switch_block].pl_node.payload_index = @intCast(u32, astgen.extra.items.len);
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const payload_index = astgen.extra.items.len;
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zir_datas[switch_block].pl_node.payload_index = @intCast(u32, payload_index);
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try astgen.extra.ensureCapacity(gpa, astgen.extra.items.len +
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scalar_cases_payload.items.len + multi_cases_payload.items.len);
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astgen.extra.appendSliceAssumeCapacity(scalar_cases_payload.items);
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astgen.extra.appendSliceAssumeCapacity(multi_cases_payload.items);
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const strat = rl.strategy(&block_scope);
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assert(strat.tag == .break_operand); // TODO
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assert(!strat.elide_store_to_block_ptr_instructions); // TODO
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assert(rl != .ref); // TODO
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const switch_block_ref = astgen.indexToRef(switch_block);
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return rvalue(parent_gz, scope, rl, switch_block_ref, switch_node);
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switch (strat.tag) {
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.break_operand => {
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// Switch expressions return `true` for `nodeMayNeedMemoryLocation` thus
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// this is always true.
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assert(strat.elide_store_to_block_ptr_instructions);
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// Elide all the `store_to_block_ptr` instructions.
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var extra_index: usize = payload_index;
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extra_index += 2;
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extra_index += @boolToInt(multi_cases_len != 0);
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if (special_prong != .none) {
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const body_len = astgen.extra.items[extra_index];
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extra_index += 1;
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const body = astgen.extra.items[extra_index..][0..body_len];
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extra_index += body_len;
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const store_inst = body[body.len - 2];
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assert(zir_tags[store_inst] == .store_to_block_ptr);
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assert(zir_datas[store_inst].bin.lhs == block_scope.rl_ptr);
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zir_tags[store_inst] = .elided;
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zir_datas[store_inst] = undefined;
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}
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var scalar_i: u32 = 0;
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while (scalar_i < scalar_cases_len) : (scalar_i += 1) {
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extra_index += 1;
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const body_len = astgen.extra.items[extra_index];
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extra_index += 1;
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const body = astgen.extra.items[extra_index..][0..body_len];
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extra_index += body_len;
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const store_inst = body[body.len - 2];
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assert(zir_tags[store_inst] == .store_to_block_ptr);
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assert(zir_datas[store_inst].bin.lhs == block_scope.rl_ptr);
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zir_tags[store_inst] = .elided;
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zir_datas[store_inst] = undefined;
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}
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var multi_i: u32 = 0;
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while (multi_i < multi_cases_len) : (multi_i += 1) {
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const items_len = astgen.extra.items[extra_index];
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extra_index += 1;
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const ranges_len = astgen.extra.items[extra_index];
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extra_index += 1;
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const body_len = astgen.extra.items[extra_index];
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extra_index += 1;
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extra_index += items_len;
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extra_index += 2 * ranges_len;
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const body = astgen.extra.items[extra_index..][0..body_len];
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extra_index += body_len;
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const store_inst = body[body.len - 2];
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assert(zir_tags[store_inst] == .store_to_block_ptr);
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assert(zir_datas[store_inst].bin.lhs == block_scope.rl_ptr);
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zir_tags[store_inst] = .elided;
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zir_datas[store_inst] = undefined;
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}
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const block_ref = astgen.indexToRef(switch_block);
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switch (rl) {
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.ref => return block_ref,
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else => return rvalue(parent_gz, scope, rl, block_ref, switch_node),
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}
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},
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.break_void => {
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assert(!strat.elide_store_to_block_ptr_instructions);
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// Modify all the terminating instruction tags to become `break` variants.
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var extra_index: usize = payload_index;
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extra_index += 2;
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extra_index += @boolToInt(multi_cases_len != 0);
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if (special_prong != .none) {
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const body_len = astgen.extra.items[extra_index];
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extra_index += 1;
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const body = astgen.extra.items[extra_index..][0..body_len];
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extra_index += body_len;
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const last = body[body.len - 1];
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assert(zir_tags[last] == .@"break");
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assert(zir_datas[last].@"break".block_inst == switch_block);
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zir_datas[last].@"break".operand = .void_value;
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}
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var scalar_i: u32 = 0;
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while (scalar_i < scalar_cases_len) : (scalar_i += 1) {
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extra_index += 1;
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const body_len = astgen.extra.items[extra_index];
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extra_index += 1;
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const body = astgen.extra.items[extra_index..][0..body_len];
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extra_index += body_len;
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const last = body[body.len - 1];
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assert(zir_tags[last] == .@"break");
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assert(zir_datas[last].@"break".block_inst == switch_block);
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zir_datas[last].@"break".operand = .void_value;
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}
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var multi_i: u32 = 0;
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while (multi_i < multi_cases_len) : (multi_i += 1) {
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const items_len = astgen.extra.items[extra_index];
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extra_index += 1;
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const ranges_len = astgen.extra.items[extra_index];
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extra_index += 1;
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const body_len = astgen.extra.items[extra_index];
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extra_index += 1;
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extra_index += items_len;
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extra_index += 2 * ranges_len;
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const body = astgen.extra.items[extra_index..][0..body_len];
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extra_index += body_len;
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const last = body[body.len - 1];
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assert(zir_tags[last] == .@"break");
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assert(zir_datas[last].@"break".block_inst == switch_block);
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zir_datas[last].@"break".operand = .void_value;
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}
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return astgen.indexToRef(switch_block);
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},
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}
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}
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fn ret(gz: *GenZir, scope: *Scope, node: ast.Node.Index) InnerError!zir.Inst.Ref {
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@ -2255,7 +2255,7 @@ fn zirSwitchBlock(
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const inst_data = sema.code.instructions.items(.data)[inst].pl_node;
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const src = inst_data.src();
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const operand_src: LazySrcLoc = .{ .node_offset_switch_operand = inst_data.src_node };
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const extra = sema.code.extraData(zir.Inst.SwitchBr, inst_data.payload_index);
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const extra = sema.code.extraData(zir.Inst.SwitchBlock, inst_data.payload_index);
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const operand_ptr = try sema.resolveInst(extra.data.operand);
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const operand = if (is_ref)
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@ -2288,7 +2288,7 @@ fn zirSwitchBlockMulti(
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const inst_data = sema.code.instructions.items(.data)[inst].pl_node;
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const src = inst_data.src();
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const operand_src: LazySrcLoc = .{ .node_offset_switch_operand = inst_data.src_node };
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const extra = sema.code.extraData(zir.Inst.SwitchBrMulti, inst_data.payload_index);
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const extra = sema.code.extraData(zir.Inst.SwitchBlockMulti, inst_data.payload_index);
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const operand_ptr = try sema.resolveInst(extra.data.operand);
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const operand = if (is_ref)
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10
src/zir.zig
10
src/zir.zig
@ -589,7 +589,7 @@ pub const Inst = struct {
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/// Uses the `small_str` field.
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enum_literal_small,
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/// A switch expression. Uses the `pl_node` union field.
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/// AST node is the switch, payload is `SwitchBr`.
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/// AST node is the switch, payload is `SwitchBlock`.
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/// All prongs of target handled.
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switch_block,
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/// Same as switch_block, except one or more prongs have multiple items.
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@ -1379,7 +1379,7 @@ pub const Inst = struct {
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/// body_len: u32,
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/// body member Index for every body_len
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/// } for every cases_len
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pub const SwitchBr = struct {
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pub const SwitchBlock = struct {
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operand: Ref,
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cases_len: u32,
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};
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@ -1408,7 +1408,7 @@ pub const Inst = struct {
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/// }
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/// body member Index for every body_len
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/// }
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pub const SwitchBrMulti = struct {
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pub const SwitchBlockMulti = struct {
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operand: Ref,
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scalar_cases_len: u32,
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multi_cases_len: u32,
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@ -1817,7 +1817,7 @@ const Writer = struct {
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special_prong: SpecialProng,
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) !void {
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const inst_data = self.code.instructions.items(.data)[inst].pl_node;
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const extra = self.code.extraData(Inst.SwitchBr, inst_data.payload_index);
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const extra = self.code.extraData(Inst.SwitchBlock, inst_data.payload_index);
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const special: struct {
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body: []const Inst.Index,
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end: usize,
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@ -1881,7 +1881,7 @@ const Writer = struct {
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special_prong: SpecialProng,
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) !void {
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const inst_data = self.code.instructions.items(.data)[inst].pl_node;
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const extra = self.code.extraData(Inst.SwitchBrMulti, inst_data.payload_index);
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const extra = self.code.extraData(Inst.SwitchBlockMulti, inst_data.payload_index);
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const special: struct {
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body: []const Inst.Index,
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end: usize,
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