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fix incorrect slicing by length detection cases #22344

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merged 3 commits into from
Dec 29, 2024
Merged

fix incorrect slicing by length detection cases #22344

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2e40a1d
simplify AstGen handling of slicing syntax
Techatrix Dec 28, 2024
5d51d44
fix slice of slice with sentinel but no end index
Techatrix Dec 29, 2024
5b6326e
fix slice of slice with sentinel on the lhs slice
Techatrix Dec 29, 2024
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111 changes: 36 additions & 75 deletions lib/std/zig/AstGen.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -876,100 +876,61 @@ fn expr(gz: *GenZir, scope: *Scope, ri: ResultInfo, node: Ast.Node.Index) InnerE

.for_simple, .@"for" => return forExpr(gz, scope, ri.br(), node, tree.fullFor(node).?, false),

.slice_open => {
const lhs = try expr(gz, scope, .{ .rl = .ref }, node_datas[node].lhs);

const cursor = maybeAdvanceSourceCursorToMainToken(gz, node);
const start = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, node_datas[node].rhs);
try emitDbgStmt(gz, cursor);
const result = try gz.addPlNode(.slice_start, node, Zir.Inst.SliceStart{
.lhs = lhs,
.start = start,
});
return rvalue(gz, ri, result, node);
},
.slice => {
const extra = tree.extraData(node_datas[node].rhs, Ast.Node.Slice);
const lhs_node = node_datas[node].lhs;
const lhs_tag = node_tags[lhs_node];
const lhs_is_slice_sentinel = lhs_tag == .slice_sentinel;
const lhs_is_open_slice = lhs_tag == .slice_open or
(lhs_is_slice_sentinel and tree.extraData(node_datas[lhs_node].rhs, Ast.Node.SliceSentinel).end == 0);
if (lhs_is_open_slice and nodeIsTriviallyZero(tree, extra.start)) {
const lhs = try expr(gz, scope, .{ .rl = .ref }, node_datas[lhs_node].lhs);

const start = if (lhs_is_slice_sentinel) start: {
const lhs_extra = tree.extraData(node_datas[lhs_node].rhs, Ast.Node.SliceSentinel);
break :start try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, lhs_extra.start);
} else try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, node_datas[lhs_node].rhs);
.slice_open,
.slice,
.slice_sentinel,
=> {
const full = tree.fullSlice(node).?;
if (full.ast.end != 0 and
node_tags[full.ast.sliced] == .slice_open and
nodeIsTriviallyZero(tree, full.ast.start))
{
const lhs_extra = tree.sliceOpen(full.ast.sliced).ast;

const lhs = try expr(gz, scope, .{ .rl = .ref }, lhs_extra.sliced);
const start = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, lhs_extra.start);
const cursor = maybeAdvanceSourceCursorToMainToken(gz, node);
const len = if (extra.end != 0) try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.end) else .none;
const len = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, full.ast.end);
const sentinel = if (full.ast.sentinel != 0) try expr(gz, scope, .{ .rl = .none }, full.ast.sentinel) else .none;
try emitDbgStmt(gz, cursor);
const result = try gz.addPlNode(.slice_length, node, Zir.Inst.SliceLength{
.lhs = lhs,
.start = start,
.len = len,
.start_src_node_offset = gz.nodeIndexToRelative(lhs_node),
.sentinel = .none,
.start_src_node_offset = gz.nodeIndexToRelative(full.ast.sliced),
.sentinel = sentinel,
});
return rvalue(gz, ri, result, node);
}
const lhs = try expr(gz, scope, .{ .rl = .ref }, node_datas[node].lhs);
const lhs = try expr(gz, scope, .{ .rl = .ref }, full.ast.sliced);

const cursor = maybeAdvanceSourceCursorToMainToken(gz, node);
const start = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.start);
const end = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.end);
const start = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, full.ast.start);
const end = if (full.ast.end != 0) try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, full.ast.end) else .none;
const sentinel = if (full.ast.sentinel != 0) try expr(gz, scope, .{ .rl = .none }, full.ast.sentinel) else .none;
try emitDbgStmt(gz, cursor);
const result = try gz.addPlNode(.slice_end, node, Zir.Inst.SliceEnd{
.lhs = lhs,
.start = start,
.end = end,
});
return rvalue(gz, ri, result, node);
},
.slice_sentinel => {
const extra = tree.extraData(node_datas[node].rhs, Ast.Node.SliceSentinel);
const lhs_node = node_datas[node].lhs;
const lhs_tag = node_tags[lhs_node];
const lhs_is_slice_sentinel = lhs_tag == .slice_sentinel;
const lhs_is_open_slice = lhs_tag == .slice_open or
(lhs_is_slice_sentinel and tree.extraData(node_datas[lhs_node].rhs, Ast.Node.SliceSentinel).end == 0);
if (lhs_is_open_slice and nodeIsTriviallyZero(tree, extra.start)) {
const lhs = try expr(gz, scope, .{ .rl = .ref }, node_datas[lhs_node].lhs);

const start = if (lhs_is_slice_sentinel) start: {
const lhs_extra = tree.extraData(node_datas[lhs_node].rhs, Ast.Node.SliceSentinel);
break :start try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, lhs_extra.start);
} else try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, node_datas[lhs_node].rhs);

const cursor = maybeAdvanceSourceCursorToMainToken(gz, node);
const len = if (extra.end != 0) try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.end) else .none;
const sentinel = try expr(gz, scope, .{ .rl = .none }, extra.sentinel);
try emitDbgStmt(gz, cursor);
const result = try gz.addPlNode(.slice_length, node, Zir.Inst.SliceLength{
if (sentinel != .none) {
const result = try gz.addPlNode(.slice_sentinel, node, Zir.Inst.SliceSentinel{
.lhs = lhs,
.start = start,
.len = len,
.start_src_node_offset = gz.nodeIndexToRelative(lhs_node),
.end = end,
.sentinel = sentinel,
});
return rvalue(gz, ri, result, node);
} else if (end != .none) {
const result = try gz.addPlNode(.slice_end, node, Zir.Inst.SliceEnd{
.lhs = lhs,
.start = start,
.end = end,
});
return rvalue(gz, ri, result, node);
} else {
const result = try gz.addPlNode(.slice_start, node, Zir.Inst.SliceStart{
.lhs = lhs,
.start = start,
});
return rvalue(gz, ri, result, node);
}
const lhs = try expr(gz, scope, .{ .rl = .ref }, node_datas[node].lhs);

const cursor = maybeAdvanceSourceCursorToMainToken(gz, node);
const start = try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.start);
const end = if (extra.end != 0) try expr(gz, scope, .{ .rl = .{ .coerced_ty = .usize_type } }, extra.end) else .none;
const sentinel = try expr(gz, scope, .{ .rl = .none }, extra.sentinel);
try emitDbgStmt(gz, cursor);
const result = try gz.addPlNode(.slice_sentinel, node, Zir.Inst.SliceSentinel{
.lhs = lhs,
.start = start,
.end = end,
.sentinel = sentinel,
});
return rvalue(gz, ri, result, node);
},

.deref => {
Expand Down
34 changes: 34 additions & 0 deletions test/behavior/slice.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,40 @@ test "comptime slice of slice preserves comptime var" {
}
}

test "open slice of open slice with sentinel" {
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO

var slice: [:0]const u8 = "hello";
_ = &slice;

comptime assert(@TypeOf(slice[0..][0.. :0]) == [:0]const u8);
try expect(slice[0..][0.. :0].len == 5);
try expect(slice[0..][0.. :0][0] == 'h');
try expect(slice[0..][0.. :0][5] == 0);

comptime assert(@TypeOf(slice[1..][0.. :0]) == [:0]const u8);
try expect(slice[1..][0.. :0].len == 4);
try expect(slice[1..][0.. :0][0] == 'e');
try expect(slice[1..][0.. :0][4] == 0);
}

test "open slice with sentinel of slice with end index" {
if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO

var slice: [:0]const u8 = "hello";
_ = &slice;

comptime assert(@TypeOf(slice[0.. :0][0..5]) == *const [5]u8);
try expect(slice[0.. :0][0..5].len == 5);
try expect(slice[0.. :0][0..5][0] == 'h');
try expect(slice[0.. :0][0..5][4] == 'o');

comptime assert(@TypeOf(slice[0.. :0][0..5 :0]) == *const [5:0]u8);
try expect(slice[0.. :0][0..5 :0].len == 5);
try expect(slice[0.. :0][0..5 :0][0] == 'h');
try expect(slice[0.. :0][0..5 :0][5] == 0);
}

test "slice of type" {
comptime {
var types_array = [_]type{ i32, f64, type };
Expand Down
18 changes: 18 additions & 0 deletions test/cases/safety/slice by length sentinel mismatch on lhs.zig
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Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
const std = @import("std");

pub fn panic(message: []const u8, stack_trace: ?*std.builtin.StackTrace, _: ?usize) noreturn {
_ = stack_trace;
if (std.mem.eql(u8, message, "sentinel mismatch: expected 1, found 3")) {
std.process.exit(0);
}
std.process.exit(1);
}
pub fn main() !void {
var buf: [4:0]u8 = .{ 1, 2, 3, 4 };
const slice = buf[0..][0..2 :1];
_ = slice;
return error.TestFailed;
}
// run
// backend=llvm
// target=native
18 changes: 18 additions & 0 deletions test/cases/safety/slice by length sentinel mismatch on rhs.zig
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Original file line number Diff line number Diff line change
@@ -0,0 +1,18 @@
const std = @import("std");

pub fn panic(message: []const u8, stack_trace: ?*std.builtin.StackTrace, _: ?usize) noreturn {
_ = stack_trace;
if (std.mem.eql(u8, message, "sentinel mismatch: expected 1, found 0")) {
std.process.exit(0);
}
std.process.exit(1);
}
pub fn main() !void {
var buf: [4:0]u8 = .{ 1, 2, 3, 4 };
const slice = buf[0.. :1][0..2];
_ = slice;
return error.TestFailed;
}
// run
// backend=llvm
// target=native
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