Commit 08eedc962d8e2582db8fb5b4a50114f2913519fd | zig

author	Andrew Kelley <andrew@ziglang.org> 2021-03-31 16:17:47-07:00
committer	Andrew Kelley <andrew@ziglang.org> 2021-03-31 16:17:47-07:00
log	08eedc962d8e2582db8fb5b4a50114f2913519fd
tree	197860260fb9db85a17de025e43a3c8014d74ac4
parent	abd06d8eab508319e5f7839c802f4a81d80a0025

Sema: fix else case code generation for switch

3 files changed, 82 insertions(+), 40 deletions(-)

src
- Sema.zig
- ir.zig
test
- stage2
  - cbe.zig

src/Sema.zig+29-25

 @@ -2328,6 +2328,7 @@ fn analyzeSwitch(
     switch_inst: zir.Inst.Index,
     src_node_offset: i32,
 ) InnerError!*Inst {
+    const gpa = sema.gpa;
     const special: struct { body: []const zir.Inst.Index, end: usize } = switch (special_prong) {
         .none => .{ .body = &.{}, .end = extra_end },
         .under, .@"else" => blk: {
 @@ -2353,7 +2354,7 @@ fn analyzeSwitch(
                 "'_' prong only allowed when switching on non-exhaustive enums",
                 .{},
             );
-            errdefer msg.destroy(sema.gpa);
+            errdefer msg.destroy(gpa);
             try sema.mod.errNote(
                 &block.base,
                 special_prong_src,
 @@ -2372,7 +2373,7 @@ fn analyzeSwitch(
         .ErrorSet => return sema.mod.fail(&block.base, src, "TODO validate switch .ErrorSet", .{}),
         .Union => return sema.mod.fail(&block.base, src, "TODO validate switch .Union", .{}),
         .Int, .ComptimeInt => {
-            var range_set = RangeSet.init(sema.gpa);
+            var range_set = RangeSet.init(gpa);
             defer range_set.deinit();
             var extra_index: usize = special.end;
 @@ -2440,7 +2441,7 @@ fn analyzeSwitch(
             check_range: {
                 if (operand.ty.zigTypeTag() == .Int) {
-                    var arena = std.heap.ArenaAllocator.init(sema.gpa);
+                    var arena = std.heap.ArenaAllocator.init(gpa);
                     defer arena.deinit();
                     const min_int = try operand.ty.minInt(&arena, sema.mod.getTarget());
 @@ -2549,7 +2550,7 @@ fn analyzeSwitch(
                 );
             }
-            var seen_values = ValueSrcMap.init(sema.gpa);
+            var seen_values = ValueSrcMap.init(gpa);
             defer seen_values.deinit();
             var extra_index: usize = special.end;
 @@ -2712,16 +2713,16 @@ fn analyzeSwitch(
         .is_comptime = block.is_comptime,
     };
     const merges = &child_block.label.?.merges;
-    defer child_block.instructions.deinit(sema.gpa);
+    defer child_block.instructions.deinit(gpa);
-    defer merges.results.deinit(sema.gpa);
+    defer merges.results.deinit(gpa);
-    defer merges.br_list.deinit(sema.gpa);
+    defer merges.br_list.deinit(gpa);
     // TODO when reworking TZIR memory layout make multi cases get generated as cases,
     // not as part of the "else" block.
     const cases = try sema.arena.alloc(Inst.SwitchBr.Case, scalar_cases_len);
     var case_block = child_block.makeSubBlock();
-    defer case_block.instructions.deinit(sema.gpa);
+    defer case_block.instructions.deinit(gpa);
     var extra_index: usize = special.end;
 @@ -2747,7 +2748,7 @@ fn analyzeSwitch(
         };
     }
-    var first_condbr: *Inst.CondBr = undefined;
+    var first_else_body: Body = undefined;
     var prev_condbr: ?*Inst.CondBr = null;
     var multi_i: usize = 0;
 @@ -2822,12 +2823,6 @@ fn analyzeSwitch(
             }
         }
-        const body = sema.code.extra[extra_index..][0..body_len];
-        extra_index += body_len;
-        _ = try sema.analyzeBody(&case_block, body);
-        const then_body: Body = .{
-            .instructions = try sema.arena.dupe(*Inst, case_block.instructions.items),
-        };
         const new_condbr = try sema.arena.create(Inst.CondBr);
         new_condbr.* = .{
             .base = .{
 @@ -2836,15 +2831,26 @@ fn analyzeSwitch(
                 .src = src,
             },
             .condition = any_ok.?,
-            .then_body = then_body,
+            .then_body = undefined,
             .else_body = undefined,
         };
+        try case_block.instructions.append(gpa, &new_condbr.base);
+        const cond_body: Body = .{
+            .instructions = try sema.arena.dupe(*Inst, case_block.instructions.items),
+        };
+        case_block.instructions.shrinkRetainingCapacity(0);
+        const body = sema.code.extra[extra_index..][0..body_len];
+        extra_index += body_len;
+        _ = try sema.analyzeBody(&case_block, body);
+        new_condbr.then_body = .{
+            .instructions = try sema.arena.dupe(*Inst, case_block.instructions.items),
+        };
         if (prev_condbr) |condbr| {
-            condbr.else_body = .{
+            condbr.else_body = cond_body;
-                .instructions = try sema.arena.dupe(*Inst, &[1]*Inst{&new_condbr.base}),
-            };
         } else {
-            first_condbr = new_condbr;
+            first_else_body = cond_body;
         }
         prev_condbr = new_condbr;
     }
 @@ -2856,11 +2862,9 @@ fn analyzeSwitch(
             const else_body: Body = .{
                 .instructions = try sema.arena.dupe(*Inst, case_block.instructions.items),
             };
-            if (prev_condbr != null) {
+            if (prev_condbr) |condbr| {
-                first_condbr.else_body = else_body;
+                condbr.else_body = else_body;
-                break :blk .{
+                break :blk first_else_body;
-                    .instructions = try sema.arena.dupe(*Inst, &[1]*Inst{&first_condbr.base}),
-                };
             } else {
                 break :blk else_body;
             }

src/ir.zig+40-2

...	@@ -774,6 +774,14 @@ const DumpTzir = struct {	...	@@ -774,6 +774,14 @@ const DumpTzir = struct {
774	try dtz.fetchInstsAndResolveConsts(condbr.then_body);	774	try dtz.fetchInstsAndResolveConsts(condbr.then_body);
775	try dtz.fetchInstsAndResolveConsts(condbr.else_body);	775	try dtz.fetchInstsAndResolveConsts(condbr.else_body);
776	},	776	},
		777	.switchbr => {
		778	const switchbr = inst.castTag(.switchbr).?;
		779	try dtz.findConst(switchbr.target);
		780	try dtz.fetchInstsAndResolveConsts(switchbr.else_body);
		781	for (switchbr.cases) \|case\| {
		782	try dtz.fetchInstsAndResolveConsts(case.body);
		783	}
		784	},
777		785
778	.loop => {	786	.loop => {
779	const loop = inst.castTag(.loop).?;	787	const loop = inst.castTag(.loop).?;
...	@@ -791,7 +799,6 @@ const DumpTzir = struct {	...	@@ -791,7 +799,6 @@ const DumpTzir = struct {
791	.assembly,	799	.assembly,
792	.constant,	800	.constant,
793	.varptr,	801	.varptr,
794	.switchbr,
795	=> {},	802	=> {},
796	}	803	}
797	}	804	}
...	@@ -981,6 +988,38 @@ const DumpTzir = struct {	...	@@ -981,6 +988,38 @@ const DumpTzir = struct {
981	try writer.writeAll("})\n");	988	try writer.writeAll("})\n");
982	},	989	},
983		990
		991	.switchbr => {
		992	const switchbr = inst.castTag(.switchbr).?;
		993
		994	const condition_kinky = try dtz.writeInst(writer, switchbr.target);
		995	if (condition_kinky != null) {
		996	try writer.writeAll(", { // Instruction does not dominate all uses!\n");
		997	} else {
		998	try writer.writeAll(", {\n");
		999	}
		1000	const old_indent = dtz.indent;
		1001
		1002	if (switchbr.else_body.instructions.len != 0) {
		1003	dtz.indent += 2;
		1004	try dtz.dumpBody(switchbr.else_body, writer);
		1005
		1006	try writer.writeByteNTimes(' ', old_indent);
		1007	try writer.writeAll("}, {\n");
		1008	dtz.indent = old_indent;
		1009	}
		1010	for (switchbr.cases) \|case\| {
		1011	dtz.indent += 2;
		1012	try dtz.dumpBody(case.body, writer);
		1013
		1014	try writer.writeByteNTimes(' ', old_indent);
		1015	try writer.writeAll("}, {\n");
		1016	dtz.indent = old_indent;
		1017	}
		1018
		1019	try writer.writeByteNTimes(' ', old_indent);
		1020	try writer.writeAll("})\n");
		1021	},
		1022
984	.loop => {	1023	.loop => {
985	const loop = inst.castTag(.loop).?;	1024	const loop = inst.castTag(.loop).?;
986		1025
...	@@ -1032,7 +1071,6 @@ const DumpTzir = struct {	...	@@ -1032,7 +1071,6 @@ const DumpTzir = struct {
1032	.assembly,	1071	.assembly,
1033	.constant,	1072	.constant,
1034	.varptr,	1073	.varptr,
1035	.switchbr,
1036	=> {	1074	=> {
1037	try writer.writeAll("!TODO!)\n");	1075	try writer.writeAll("!TODO!)\n");
1038	},	1076	},

test/stage2/cbe.zig+13-13

...	@@ -266,19 +266,19 @@ pub fn addCases(ctx: *TestContext) !void {	...	@@ -266,19 +266,19 @@ pub fn addCases(ctx: *TestContext) !void {
266	, "");	266	, "");
267		267
268	// Switch expression	268	// Switch expression
269	//case.addCompareOutput(	269	case.addCompareOutput(
270	// \\export fn main() c_int {	270	\\export fn main() c_int {
271	// \\ var cond: c_int = 0;	271	\\ var cond: c_int = 0;
272	// \\ var a: c_int = switch (cond) {	272	\\ var a: c_int = switch (cond) {
273	// \\ 1 => 1,	273	\\ 1 => 1,
274	// \\ 2 => 2,	274	\\ 2 => 2,
275	// \\ 99...300, 12 => 3,	275	\\ 99...300, 12 => 3,
276	// \\ 0 => 4,	276	\\ 0 => 4,
277	// \\ else => 5,	277	\\ else => 5,
278	// \\ };	278	\\ };
279	// \\ return a - 4;	279	\\ return a - 4;
280	// \\}	280	\\}
281	//, "");	281	, "");
282	}	282	}
283	//{	283	//{
284	// var case = ctx.exeFromCompiledC("optionals", .{});	284	// var case = ctx.exeFromCompiledC("optionals", .{});