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keep temporary list from escaping parseParamDeclList, make SmallSpan.multi hold Node.SubRange instead of owned memory

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This commit is contained in:
Matthew Borkowski 2021-05-27 14:30:42 -04:00
parent 9ddd12ea14
commit 80c86ec960
1 changed files with 25 additions and 26 deletions
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51
lib/std/zig/parse.zig
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@ -97,6 +97,11 @@ const Parser = struct {
extra_data: std.ArrayListUnmanaged(Node.Index),
scratch: std.ArrayListUnmanaged(Node.Index),
const SmallSpan = union(enum) {
zero_or_one: Node.Index,
multi: Node.SubRange,
};
const Members = struct {
len: usize,
lhs: Node.Index,
@ -639,9 +644,6 @@ const Parser = struct {
const fn_proto_index = try p.reserveNode();
_ = p.eatToken(.identifier);
const scratch_top = p.scratch.items.len;
defer p.scratch.shrinkRetainingCapacity(scratch_top);
// parseParamDeclList does not shrink scratch buffer, but we will
const params = try p.parseParamDeclList();
const align_expr = try p.parseByteAlign();
const section_expr = try p.parseLinkSection();
@ -656,17 +658,16 @@ const Parser = struct {
}
if (align_expr == 0 and section_expr == 0 and callconv_expr == 0) {
switch (params.len) {
0, 1 => return p.setNode(fn_proto_index, .{
switch (params) {
.zero_or_one => |param| return p.setNode(fn_proto_index, .{
.tag = .fn_proto_simple,
.main_token = fn_token,
.data = .{
.lhs = if (params.len > 0) params[0] else 0,
.lhs = param,
.rhs = return_type_expr,
},
}),
else => {
const span = try p.listToSpan(params);
.multi => |span| {
return p.setNode(fn_proto_index, .{
.tag = .fn_proto_multi,
.main_token = fn_token,
@ -681,13 +682,13 @@ const Parser = struct {
},
}
}
switch (params.len) {
0, 1 => return p.setNode(fn_proto_index, .{
switch (params) {
.zero_or_one => |param| return p.setNode(fn_proto_index, .{
.tag = .fn_proto_one,
.main_token = fn_token,
.data = .{
.lhs = try p.addExtra(Node.FnProtoOne{
.param = if (params.len > 0) params[0] else 0,
.param = param,
.align_expr = align_expr,
.section_expr = section_expr,
.callconv_expr = callconv_expr,
@ -695,8 +696,7 @@ const Parser = struct {
.rhs = return_type_expr,
},
}),
else => {
const span = try p.listToSpan(params);
.multi => |span| {
return p.setNode(fn_proto_index, .{
.tag = .fn_proto,
.main_token = fn_token,
@ -3550,13 +3550,10 @@ const Parser = struct {
}
/// ParamDeclList <- (ParamDecl COMMA)* ParamDecl?
fn parseParamDeclList(p: *Parser) ![]Node.Index {
const scratch_top = p.scratch.items.len;
// don't defer p.scratch.shrinkRetainingCapacity because caller will do it
fn parseParamDeclList(p: *Parser) !SmallSpan {
_ = try p.expectToken(.l_paren);
if (p.eatToken(.r_paren)) |_| {
return p.scratch.items[scratch_top..];
return SmallSpan{ .zero_or_one = 0 };
}
const param_one = while (true) {
const param = try p.expectParamDecl();
@ -3564,10 +3561,10 @@ const Parser = struct {
switch (p.token_tags[p.nextToken()]) {
.comma => {
if (p.eatToken(.r_paren)) |_| {
return p.scratch.items[scratch_top..];
return SmallSpan{ .zero_or_one = 0 };
}
},
.r_paren => return p.scratch.items[scratch_top..],
.r_paren => return SmallSpan{ .zero_or_one = 0 },
else => {
// This is likely just a missing comma;
// give an error but continue parsing this list.
@ -3576,12 +3573,11 @@ const Parser = struct {
},
}
} else unreachable;
try p.scratch.append(p.gpa, param_one);
const param_two = while (true) {
switch (p.token_tags[p.nextToken()]) {
.comma => {},
.r_paren => return p.scratch.items[scratch_top..],
.r_paren => return SmallSpan{ .zero_or_one = param_one },
.colon, .r_brace, .r_bracket => {
p.tok_i -= 1;
return p.failExpected(.r_paren);
@ -3594,17 +3590,20 @@ const Parser = struct {
},
}
if (p.eatToken(.r_paren)) |_| {
return p.scratch.items[scratch_top..];
return SmallSpan{ .zero_or_one = param_one };
}
const param = try p.expectParamDecl();
if (param != 0) break param;
} else unreachable;
try p.scratch.append(p.gpa, param_two);
const scratch_top = p.scratch.items.len;
defer p.scratch.shrinkRetainingCapacity(scratch_top);
try p.scratch.appendSlice(p.gpa, &.{ param_one, param_two });
while (true) {
switch (p.token_tags[p.nextToken()]) {
.comma => {},
.r_paren => return p.scratch.items[scratch_top..],
.r_paren => return SmallSpan{ .multi = try p.listToSpan(p.scratch.items[scratch_top..]) },
.colon, .r_brace, .r_bracket => {
p.tok_i -= 1;
return p.failExpected(.r_paren);
@ -3617,7 +3616,7 @@ const Parser = struct {
},
}
if (p.eatToken(.r_paren)) |_| {
return p.scratch.items[scratch_top..];
return SmallSpan{ .multi = try p.listToSpan(p.scratch.items[scratch_top..]) };
}
const param = try p.expectParamDecl();
if (param != 0) try p.scratch.append(p.gpa, param);