authorgravatar for git@vexu.euVeikka Tuominen <git@vexu.eu> 2022-08-05 17:36:45+03:00
committergravatar for git@vexu.euVeikka Tuominen <git@vexu.eu> 2022-08-05 22:13:58+03:00
log9116e26c1ffb49cf68bebf3af2a019af08474d12
treed978f21d18c6c1f00e6ad94f7219b836b8651eb4
parent5605f6e0e302cbf345a5229ea58aef6757fe139d

Sema: add null check for implicit casts

5 files changed, 46 insertions(+), 28 deletions(-)

src/Sema.zig+18-4
...@@ -1577,8 +1577,7 @@ pub fn setupErrorReturnTrace(sema: *Sema, block: *Block, last_arg_index: usize)...@@ -1577,8 +1577,7 @@ pub fn setupErrorReturnTrace(sema: *Sema, block: *Block, last_arg_index: usize)
15771577
1578 // st.index = 0;1578 // st.index = 0;
1579 const index_field_ptr = try sema.fieldPtr(&err_trace_block, src, st_ptr, "index", src, true);1579 const index_field_ptr = try sema.fieldPtr(&err_trace_block, src, st_ptr, "index", src, true);
1580 const zero = try sema.addConstant(Type.usize, Value.zero);1580 try sema.storePtr2(&err_trace_block, src, index_field_ptr, src, .zero_usize, src, .store);
1581 try sema.storePtr2(&err_trace_block, src, index_field_ptr, src, zero, src, .store);
15821581
1583 // @errorReturnTrace() = &st;1582 // @errorReturnTrace() = &st;
1584 _ = try err_trace_block.addUnOp(.set_err_return_trace, st_ptr);1583 _ = try err_trace_block.addUnOp(.set_err_return_trace, st_ptr);
...@@ -17134,7 +17133,7 @@ fn zirAlignCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!A...@@ -17134,7 +17133,7 @@ fn zirAlignCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!A
17134 const is_aligned = try block.addBinOp(.cmp_eq, remainder, .zero_usize);17133 const is_aligned = try block.addBinOp(.cmp_eq, remainder, .zero_usize);
17135 const ok = if (ptr_ty.isSlice()) ok: {17134 const ok = if (ptr_ty.isSlice()) ok: {
17136 const len = try sema.analyzeSliceLen(block, ptr_src, ptr);17135 const len = try sema.analyzeSliceLen(block, ptr_src, ptr);
17137 const len_zero = try block.addBinOp(.cmp_eq, len, try sema.addConstant(Type.usize, Value.zero));17136 const len_zero = try block.addBinOp(.cmp_eq, len, .zero_usize);
17138 break :ok try block.addBinOp(.bit_or, len_zero, is_aligned);17137 break :ok try block.addBinOp(.bit_or, len_zero, is_aligned);
17139 } else is_aligned;17138 } else is_aligned;
17140 try sema.addSafetyCheck(block, ok, .incorrect_alignment);17139 try sema.addSafetyCheck(block, ok, .incorrect_alignment);
...@@ -21957,7 +21956,6 @@ fn coerceExtra(...@@ -21957,7 +21956,6 @@ fn coerceExtra(
21957 .ok => {},21956 .ok => {},
21958 else => break :src_c_ptr,21957 else => break :src_c_ptr,
21959 }21958 }
21960 // TODO add safety check for null pointer
21961 return sema.coerceCompatiblePtrs(block, dest_ty, inst, inst_src);21959 return sema.coerceCompatiblePtrs(block, dest_ty, inst, inst_src);
21962 }21960 }
2196321961
...@@ -24430,6 +24428,22 @@ fn coerceCompatiblePtrs(...@@ -24430,6 +24428,22 @@ fn coerceCompatiblePtrs(
24430 return sema.addConstant(dest_ty, val);24428 return sema.addConstant(dest_ty, val);
24431 }24429 }
24432 try sema.requireRuntimeBlock(block, inst_src, null);24430 try sema.requireRuntimeBlock(block, inst_src, null);
24431 const inst_ty = sema.typeOf(inst);
24432 const inst_allows_zero = (inst_ty.zigTypeTag() == .Pointer and inst_ty.ptrAllowsZero()) or true;
24433 if (block.wantSafety() and inst_allows_zero and !dest_ty.ptrAllowsZero()) {
24434 const actual_ptr = if (inst_ty.isSlice())
24435 try sema.analyzeSlicePtr(block, inst_src, inst, inst_ty)
24436 else
24437 inst;
24438 const ptr_int = try block.addUnOp(.ptrtoint, actual_ptr);
24439 const is_non_zero = try block.addBinOp(.cmp_neq, ptr_int, .zero_usize);
24440 const ok = if (inst_ty.isSlice()) ok: {
24441 const len = try sema.analyzeSliceLen(block, inst_src, inst);
24442 const len_zero = try block.addBinOp(.cmp_eq, len, .zero_usize);
24443 break :ok try block.addBinOp(.bit_or, len_zero, is_non_zero);
24444 } else is_non_zero;
24445 try sema.addSafetyCheck(block, ok, .cast_to_null);
24446 }
24433 return sema.bitCast(block, dest_ty, inst, inst_src);24447 return sema.bitCast(block, dest_ty, inst, inst_src);
24434}24448}
2443524449
test/cases/safety/pointer casting null to non-optional pointer.zig +7-3
...@@ -1,16 +1,20 @@...@@ -1,16 +1,20 @@
1const std = @import("std");1const std = @import("std");
22
3pub fn panic(message: []const u8, stack_trace: ?*std.builtin.StackTrace) noreturn {3pub fn panic(message: []const u8, stack_trace: ?*std.builtin.StackTrace) noreturn {
4 _ = message;
5 _ = stack_trace;4 _ = stack_trace;
6 std.process.exit(0);5 if (std.mem.eql(u8, message, "cast causes pointer to be null")) {
6 std.process.exit(0);
7 }
8 std.process.exit(1);
7}9}
10
8pub fn main() !void {11pub fn main() !void {
9 var c_ptr: [*c]u8 = 0;12 var c_ptr: [*c]u8 = 0;
10 var zig_ptr: *u8 = c_ptr;13 var zig_ptr: *u8 = c_ptr;
11 _ = zig_ptr;14 _ = zig_ptr;
12 return error.TestFailed;15 return error.TestFailed;
13}16}
17
14// run18// run
15// backend=stage119// backend=llvm
16// target=native20// target=native
test/cases/safety/slicing null C pointer - runtime len.zig created+20
...@@ -0,0 +1,20 @@
1const std = @import("std");
2
3pub fn panic(message: []const u8, stack_trace: ?*std.builtin.StackTrace) noreturn {
4 _ = stack_trace;
5 if (std.mem.eql(u8, message, "attempt to use null value")) {
6 std.process.exit(0);
7 }
8 std.process.exit(1);
9}
10
11pub fn main() !void {
12 var ptr: [*c]const u32 = null;
13 var len: usize = 3;
14 var slice = ptr[0..len];
15 _ = slice;
16 return error.TestFailed;
17}
18// run
19// backend=llvm
20// target=native
test/cases/safety/slicing null C pointer runtime len.zig deleted-20
...@@ -1,20 +0,0 @@
1const std = @import("std");
2
3pub fn panic(message: []const u8, stack_trace: ?*std.builtin.StackTrace) noreturn {
4 _ = stack_trace;
5 if (std.mem.eql(u8, message, "attempt to use null value")) {
6 std.process.exit(0);
7 }
8 std.process.exit(1);
9}
10
11pub fn main() !void {
12 var ptr: [*c]const u32 = null;
13 var len: usize = 3;
14 var slice = ptr[0..len];
15 _ = slice;
16 return error.TestFailed;
17}
18// run
19// backend=llvm
20// target=native
\ No newline at end of file
test/cases/safety/slicing null C pointer.zig +1-1
...@@ -16,4 +16,4 @@ pub fn main() !void {...@@ -16,4 +16,4 @@ pub fn main() !void {
16}16}
17// run17// run
18// backend=llvm18// backend=llvm
19// target=native
\ No newline at end of file
19// target=native