| author |  Andrew Kelley <andrew@ziglang.org> 2019-02-14 00:40:39-05:00 |
| committer | Andrew Kelley <andrew@ziglang.org> 2019-02-14 00:40:39-05:00 |
| log | d4d2718bca9e23ceec029bb505c0ea1b91c875b6 |
| tree | c2b7b61f36fff694f5ff030fde50846b23c690cd |
| parent | 5699ab5e77f8d13cac1e34775e6e51358119965c |
| signature | Commit is signed but in an unrecognized format. |
comptime detection of casting null to pointer
See #10592 files changed, 34 insertions(+), 3 deletions(-)
src
src/ir.cpp+14-3
| ... | ... | @@ -20645,12 +20645,23 @@ static IrInstruction *ir_analyze_ptr_cast(IrAnalyze *ira, IrInstruction *source_ |
| 20645 | 20645 | } |
| 20646 | 20646 | |
| 20647 | 20647 | if (instr_is_comptime(ptr)) { |
| 20648 | // Undefined is OK here; @ptrCast is defined to reinterpret the bit pattern | |
| 20649 | // of the pointer as the new pointer type. | |
| 20650 | ConstExprValue *val = ir_resolve_const(ira, ptr, UndefOk); | |
| 20648 | bool dest_allows_addr_zero = ptr_allows_addr_zero(dest_type); | |
| 20649 | UndefAllowed is_undef_allowed = dest_allows_addr_zero ? UndefOk : UndefBad; | |
| 20650 | ConstExprValue *val = ir_resolve_const(ira, ptr, is_undef_allowed); | |
| 20651 | 20651 | if (!val) |
| 20652 | 20652 | return ira->codegen->invalid_instruction; |
| 20653 | 20653 | |
| 20654 | if (val->special == ConstValSpecialStatic) { | |
| 20655 | bool is_addr_zero = val->data.x_ptr.special == ConstPtrSpecialNull || | |
| 20656 | (val->data.x_ptr.special == ConstPtrSpecialHardCodedAddr && | |
| 20657 | val->data.x_ptr.data.hard_coded_addr.addr == 0); | |
| 20658 | if (is_addr_zero && !dest_allows_addr_zero) { | |
| 20659 | ir_add_error(ira, source_instr, | |
| 20660 | buf_sprintf("null pointer casted to type '%s'", buf_ptr(&dest_type->name))); | |
| 20661 | return ira->codegen->invalid_instruction; | |
| 20662 | } | |
| 20663 | } | |
| 20664 | ||
| 20654 | 20665 | IrInstruction *result = ir_const(ira, source_instr, dest_type); |
| 20655 | 20666 | copy_const_val(&result->value, val, false); |
| 20656 | 20667 | result->value.type = dest_type; |
test/compile_errors.zig+20
| ... | ... | @@ -1,6 +1,26 @@ |
| 1 | 1 | const tests = @import("tests.zig"); |
| 2 | 2 | |
| 3 | 3 | pub fn addCases(cases: *tests.CompileErrorContext) void { |
| 4 | cases.addTest( | |
| 5 | "implicit casting null c pointer to zig pointer", | |
| 6 | \\comptime { | |
| 7 | \\ var c_ptr: [*c]u8 = 0; | |
| 8 | \\ var zig_ptr: *u8 = c_ptr; | |
| 9 | \\} | |
| 10 | , | |
| 11 | ".tmp_source.zig:3:24: error: null pointer casted to type '*u8'", | |
| 12 | ); | |
| 13 | ||
| 14 | cases.addTest( | |
| 15 | "implicit casting undefined c pointer to zig pointer", | |
| 16 | \\comptime { | |
| 17 | \\ var c_ptr: [*c]u8 = undefined; | |
| 18 | \\ var zig_ptr: *u8 = c_ptr; | |
| 19 | \\} | |
| 20 | , | |
| 21 | ".tmp_source.zig:3:24: error: use of undefined value here causes undefined behavior", | |
| 22 | ); | |
| 23 | ||
| 4 | 24 | cases.addTest( |
| 5 | 25 | "implicit casting C pointers which would mess up null semantics", |
| 6 | 26 | \\export fn entry() void { |