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AstGen: avoid accessing value from inner scope

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While continue expressions can access the capture, so ensure that it is
unwrapped in an outer scope.
This commit is contained in:
Jacob Young 2022-10-30 15:09:45 -04:00
parent 8caed48460
commit 5c3a486639
1 changed files with 38 additions and 34 deletions
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72
src/AstGen.zig
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@ -5910,8 +5910,8 @@ fn whileExpr(
defer loop_scope.unstack();
defer loop_scope.labeled_breaks.deinit(astgen.gpa);
var continue_scope = parent_gz.makeSubBlock(&loop_scope.base);
defer continue_scope.unstack();
var cond_scope = parent_gz.makeSubBlock(&loop_scope.base);
defer cond_scope.unstack();
const payload_is_ref = if (while_full.payload_token) |payload_token|
token_tags[payload_token] == .asterisk
@ -5925,22 +5925,22 @@ fn whileExpr(
} = c: {
if (while_full.error_token) |_| {
const cond_ri: ResultInfo = .{ .rl = if (payload_is_ref) .ref else .none };
const err_union = try expr(&continue_scope, &continue_scope.base, cond_ri, while_full.ast.cond_expr);
const err_union = try expr(&cond_scope, &cond_scope.base, cond_ri, while_full.ast.cond_expr);
const tag: Zir.Inst.Tag = if (payload_is_ref) .is_non_err_ptr else .is_non_err;
break :c .{
.inst = err_union,
.bool_bit = try continue_scope.addUnNode(tag, err_union, while_full.ast.then_expr),
.bool_bit = try cond_scope.addUnNode(tag, err_union, while_full.ast.then_expr),
};
} else if (while_full.payload_token) |_| {
const cond_ri: ResultInfo = .{ .rl = if (payload_is_ref) .ref else .none };
const optional = try expr(&continue_scope, &continue_scope.base, cond_ri, while_full.ast.cond_expr);
const optional = try expr(&cond_scope, &cond_scope.base, cond_ri, while_full.ast.cond_expr);
const tag: Zir.Inst.Tag = if (payload_is_ref) .is_non_null_ptr else .is_non_null;
break :c .{
.inst = optional,
.bool_bit = try continue_scope.addUnNode(tag, optional, while_full.ast.then_expr),
.bool_bit = try cond_scope.addUnNode(tag, optional, while_full.ast.then_expr),
};
} else {
const cond = try expr(&continue_scope, &continue_scope.base, bool_ri, while_full.ast.cond_expr);
const cond = try expr(&cond_scope, &cond_scope.base, bool_ri, while_full.ast.cond_expr);
break :c .{
.inst = cond,
.bool_bit = cond,
@ -5949,16 +5949,16 @@ fn whileExpr(
};
const condbr_tag: Zir.Inst.Tag = if (is_inline) .condbr_inline else .condbr;
const condbr = try continue_scope.addCondBr(condbr_tag, node);
const condbr = try cond_scope.addCondBr(condbr_tag, node);
const block_tag: Zir.Inst.Tag = if (is_inline) .block_inline else .block;
const cond_block = try loop_scope.makeBlockInst(block_tag, node);
try continue_scope.setBlockBody(cond_block);
// continue_scope unstacked now, can add new instructions to loop_scope
try cond_scope.setBlockBody(cond_block);
// cond_scope unstacked now, can add new instructions to loop_scope
try loop_scope.instructions.append(astgen.gpa, cond_block);
// make scope now but don't stack on parent_gz until loop_scope
// gets unstacked after cont_expr is emitted and added below
var then_scope = parent_gz.makeSubBlock(&continue_scope.base);
var then_scope = parent_gz.makeSubBlock(&cond_scope.base);
then_scope.instructions_top = GenZir.unstacked_top;
defer then_scope.unstack();
@ -6026,24 +6026,17 @@ fn whileExpr(
}
};
// This code could be improved to avoid emitting the continue expr when there
// are no jumps to it. This happens when the last statement of a while body is noreturn
// and there are no `continue` statements.
// Tracking issue: https://github.com/ziglang/zig/issues/9185
try then_scope.addDbgBlockBegin();
if (dbg_var_name) |some| {
try then_scope.addDbgVar(.dbg_var_val, some, dbg_var_inst);
}
if (while_full.ast.cont_expr != 0) {
_ = try unusedResultExpr(&loop_scope, then_sub_scope, while_full.ast.cont_expr);
}
try then_scope.addDbgBlockEnd();
var continue_scope = parent_gz.makeSubBlock(then_sub_scope);
continue_scope.instructions_top = GenZir.unstacked_top;
defer continue_scope.unstack();
const continue_block = try then_scope.makeBlockInst(block_tag, node);
const repeat_tag: Zir.Inst.Tag = if (is_inline) .repeat_inline else .repeat;
_ = try loop_scope.addNode(repeat_tag, node);
try loop_scope.setBlockBody(loop_block);
loop_scope.break_block = loop_block;
loop_scope.continue_block = cond_block;
loop_scope.continue_block = continue_block;
if (while_full.label_token) |label_token| {
loop_scope.label = @as(?GenZir.Label, GenZir.Label{
.token = label_token,
@ -6054,18 +6047,30 @@ fn whileExpr(
// done adding instructions to loop_scope, can now stack then_scope
then_scope.instructions_top = then_scope.instructions.items.len;
if (payload_inst != 0) try then_scope.instructions.append(astgen.gpa, payload_inst);
try then_scope.addDbgBlockBegin();
if (dbg_var_name) |some| {
try then_scope.addDbgVar(.dbg_var_val, some, dbg_var_inst);
if (payload_inst != 0) try then_scope.instructions.append(astgen.gpa, payload_inst);
if (dbg_var_name) |name| try then_scope.addDbgVar(.dbg_var_val, name, dbg_var_inst);
try then_scope.instructions.append(astgen.gpa, continue_block);
// This code could be improved to avoid emitting the continue expr when there
// are no jumps to it. This happens when the last statement of a while body is noreturn
// and there are no `continue` statements.
// Tracking issue: https://github.com/ziglang/zig/issues/9185
if (while_full.ast.cont_expr != 0) {
_ = try unusedResultExpr(&then_scope, then_sub_scope, while_full.ast.cont_expr);
}
const then_result = try expr(&then_scope, then_sub_scope, .{ .rl = .none }, while_full.ast.then_expr);
_ = try addEnsureResult(&then_scope, then_result, while_full.ast.then_expr);
try checkUsed(parent_gz, &then_scope.base, then_sub_scope);
try then_scope.addDbgBlockEnd();
var else_scope = parent_gz.makeSubBlock(&continue_scope.base);
continue_scope.instructions_top = continue_scope.instructions.items.len;
_ = try unusedResultExpr(&continue_scope, &continue_scope.base, while_full.ast.then_expr);
try checkUsed(parent_gz, &then_scope.base, then_sub_scope);
const break_tag: Zir.Inst.Tag = if (is_inline) .break_inline else .@"break";
if (!continue_scope.endsWithNoReturn()) {
const break_inst = try continue_scope.makeBreak(break_tag, continue_block, .void_value);
try then_scope.instructions.append(astgen.gpa, break_inst);
}
try continue_scope.setBlockBody(continue_block);
var else_scope = parent_gz.makeSubBlock(&cond_scope.base);
defer else_scope.unstack();
const else_node = while_full.ast.else_expr;
@ -6128,7 +6133,6 @@ fn whileExpr(
try astgen.appendErrorTok(some.token, "unused while loop label", .{});
}
}
const break_tag: Zir.Inst.Tag = if (is_inline) .break_inline else .@"break";
const result = try finishThenElseBlock(
parent_gz,
ri,
@ -6138,7 +6142,7 @@ fn whileExpr(
&else_scope,
condbr,
cond.bool_bit,
then_result,
.void_value,
else_info.result,
loop_block,
cond_block,