| author |  Andrew Kelley <andrew@ziglang.org> 2024-03-20 17:02:35-07:00 |
| committer | Andrew Kelley <andrew@ziglang.org> 2024-03-20 17:02:35-07:00 |
| log | 2583b389eaf5f7aaa0eb79b51126506c1e172d15 |
| tree | 2ff98baf24f1738e4401c88207a5a8c8edeffa1f |
| parent | ab22844176f422aeb4f523ba38f21b12d78760b3 |
frontend: comptime array slice-by-length OOB detection
3 files changed, 45 insertions(+), 11 deletions(-)
src- test
- cases
- compile_errors
src/Sema.zig+28-9
| ... | @@ -33285,15 +33285,34 @@ fn analyzeSlice( | ... | @@ -33285,15 +33285,34 @@ fn analyzeSlice( |
| 33285 | } | 33285 | } |
| 33286 | 33286 | ||
| 33287 | bounds_check: { | 33287 | bounds_check: { |
| 33288 | const actual_len = if (array_ty.zigTypeTag(mod) == .Array) | 33288 | const actual_len = l: { |
| 33289 | try mod.intRef(Type.usize, array_ty.arrayLenIncludingSentinel(mod)) | 33289 | if (array_ty.zigTypeTag(mod) == .Array) { |
| 33290 | else if (slice_ty.isSlice(mod)) l: { | 33290 | const len = array_ty.arrayLenIncludingSentinel(mod); |
| 33291 | const slice_len_inst = try block.addTyOp(.slice_len, Type.usize, ptr_or_slice); | 33291 | // If the end is comptime-known, we can emit a |
| 33292 | break :l if (slice_ty.sentinel(mod) == null) | 33292 | // compile error if it would be out-of-bounds even |
| 33293 | slice_len_inst | 33293 | // with a start value of 0. |
| 33294 | else | 33294 | if (uncasted_end_opt != .none) { |
| 33295 | try sema.analyzeArithmetic(block, .add, slice_len_inst, .one, src, end_src, end_src, true); | 33295 | if (try sema.resolveDefinedValue(block, end_src, uncasted_end_opt)) |end_val| { |
| 33296 | } else break :bounds_check; | 33296 | const end_int = end_val.getUnsignedInt(mod).?; |
| 33297 | if (end_int > len) return sema.fail( | ||
| 33298 | block, | ||
| 33299 | end_src, | ||
| 33300 | "slice end index {d} exceeds array length of type '{}'", | ||
| 33301 | .{ end_int, array_ty.fmt(mod) }, | ||
| 33302 | ); | ||
| 33303 | } | ||
| 33304 | } | ||
| 33305 | break :l try mod.intRef(Type.usize, len); | ||
| 33306 | } | ||
| 33307 | if (slice_ty.isSlice(mod)) { | ||
| 33308 | const slice_len_inst = try block.addTyOp(.slice_len, Type.usize, ptr_or_slice); | ||
| 33309 | break :l if (slice_ty.sentinel(mod) == null) | ||
| 33310 | slice_len_inst | ||
| 33311 | else | ||
| 33312 | try sema.analyzeArithmetic(block, .add, slice_len_inst, .one, src, end_src, end_src, true); | ||
| 33313 | } | ||
| 33314 | break :bounds_check; | ||
| 33315 | }; | ||
| 33297 | 33316 | ||
| 33298 | const actual_end = if (slice_sentinel != null) | 33317 | const actual_end = if (slice_sentinel != null) |
| 33299 | try sema.analyzeArithmetic(block, .add, end, .one, src, end_src, end_src, true) | 33318 | try sema.analyzeArithmetic(block, .add, end, .one, src, end_src, end_src, true) |
test/cases/compile_errors/out of bounds array slice by length.zig created+15
| ... | @@ -0,0 +1,15 @@ | ||
| 1 | export fn b() void { | ||
| 2 | var buf: [5]u8 = undefined; | ||
| 3 | _ = buf[foo(6)..][0..10]; | ||
| 4 | return error.TestFailed; | ||
| 5 | } | ||
| 6 | |||
| 7 | fn foo(a: u32) u32 { | ||
| 8 | return a; | ||
| 9 | } | ||
| 10 | |||
| 11 | // error | ||
| 12 | // backend=stage2 | ||
| 13 | // target=native | ||
| 14 | // | ||
| 15 | // :3:26: error: slice end index 10 exceeds array length of type '[5]u8' | ||
test/cases/safety/out of bounds array slice by length.zig +2-2
| ... | @@ -2,14 +2,14 @@ const std = @import("std"); | ... | @@ -2,14 +2,14 @@ const std = @import("std"); |
| 2 | 2 | ||
| 3 | pub fn panic(message: []const u8, stack_trace: ?*std.builtin.StackTrace, _: ?usize) noreturn { | 3 | pub fn panic(message: []const u8, stack_trace: ?*std.builtin.StackTrace, _: ?usize) noreturn { |
| 4 | _ = stack_trace; | 4 | _ = stack_trace; |
| 5 | if (std.mem.eql(u8, message, "index out of bounds: index 16, len 5")) { | 5 | if (std.mem.eql(u8, message, "index out of bounds: index 9, len 5")) { |
| 6 | std.process.exit(0); | 6 | std.process.exit(0); |
| 7 | } | 7 | } |
| 8 | std.process.exit(1); | 8 | std.process.exit(1); |
| 9 | } | 9 | } |
| 10 | pub fn main() !void { | 10 | pub fn main() !void { |
| 11 | var buf: [5]u8 = undefined; | 11 | var buf: [5]u8 = undefined; |
| 12 | _ = buf[foo(6)..][0..10]; | 12 | _ = buf[foo(6)..][0..3]; |
| 13 | return error.TestFailed; | 13 | return error.TestFailed; |
| 14 | } | 14 | } |
| 15 | fn foo(a: u32) u32 { | 15 | fn foo(a: u32) u32 { |