Commit 72ca2b214d
Changed files (5)
src/codegen.cpp
@@ -4201,6 +4201,7 @@ static LLVMValueRef gen_const_val(CodeGen *g, ConstExprValue *const_val, const c
continue;
}
ConstExprValue *field_val = &const_val->data.x_struct.fields[i];
+ assert(field_val->type != nullptr);
LLVMValueRef val = gen_const_val(g, field_val, "");
fields[type_struct_field->gen_index] = val;
make_unnamed_struct = make_unnamed_struct || is_llvm_value_unnamed_type(field_val->type, val);
src/ir.cpp
@@ -8183,7 +8183,7 @@ static IrInstruction *ir_get_ref(IrAnalyze *ira, IrInstruction *source_instructi
}
if (instr_is_comptime(value)) {
- ConstExprValue *val = ir_resolve_const(ira, value, UndefBad);
+ ConstExprValue *val = ir_resolve_const(ira, value, UndefOk);
if (!val)
return ira->codegen->invalid_instruction;
bool final_is_const = (value->value.type->id == TypeTableEntryIdMetaType) ? is_const : true;
@@ -14931,6 +14931,7 @@ static TypeTableEntry *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstructio
ConstExprValue *parent_ptr;
size_t abs_offset;
size_t rel_end;
+ bool ptr_is_undef = false;
if (array_type->id == TypeTableEntryIdArray) {
array_val = const_ptr_pointee(ira->codegen, &ptr_ptr->value);
abs_offset = 0;
@@ -14938,7 +14939,12 @@ static TypeTableEntry *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstructio
parent_ptr = nullptr;
} else if (array_type->id == TypeTableEntryIdPointer) {
parent_ptr = const_ptr_pointee(ira->codegen, &ptr_ptr->value);
- switch (parent_ptr->data.x_ptr.special) {
+ if (parent_ptr->special == ConstValSpecialUndef) {
+ array_val = nullptr;
+ abs_offset = 0;
+ rel_end = SIZE_MAX;
+ ptr_is_undef = true;
+ } else switch (parent_ptr->data.x_ptr.special) {
case ConstPtrSpecialInvalid:
case ConstPtrSpecialDiscard:
zig_unreachable();
@@ -14992,7 +14998,7 @@ static TypeTableEntry *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstructio
}
uint64_t start_scalar = bigint_as_unsigned(&casted_start->value.data.x_bigint);
- if (start_scalar > rel_end) {
+ if (!ptr_is_undef && start_scalar > rel_end) {
ir_add_error(ira, &instruction->base, buf_sprintf("out of bounds slice"));
return ira->codegen->builtin_types.entry_invalid;
}
@@ -15003,12 +15009,18 @@ static TypeTableEntry *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstructio
} else {
end_scalar = rel_end;
}
- if (end_scalar > rel_end) {
- ir_add_error(ira, &instruction->base, buf_sprintf("out of bounds slice"));
- return ira->codegen->builtin_types.entry_invalid;
+ if (!ptr_is_undef) {
+ if (end_scalar > rel_end) {
+ ir_add_error(ira, &instruction->base, buf_sprintf("out of bounds slice"));
+ return ira->codegen->builtin_types.entry_invalid;
+ }
+ if (start_scalar > end_scalar) {
+ ir_add_error(ira, &instruction->base, buf_sprintf("slice start is greater than end"));
+ return ira->codegen->builtin_types.entry_invalid;
+ }
}
- if (start_scalar > end_scalar) {
- ir_add_error(ira, &instruction->base, buf_sprintf("slice start is greater than end"));
+ if (ptr_is_undef && start_scalar != end_scalar) {
+ ir_add_error(ira, &instruction->base, buf_sprintf("non-zero length slice of undefined pointer"));
return ira->codegen->builtin_types.entry_invalid;
}
@@ -15024,25 +15036,27 @@ static TypeTableEntry *ir_analyze_instruction_slice(IrAnalyze *ira, IrInstructio
if (array_type->id == TypeTableEntryIdArray) {
ptr_val->data.x_ptr.mut = ptr_ptr->value.data.x_ptr.mut;
}
- } else {
- switch (parent_ptr->data.x_ptr.special) {
- case ConstPtrSpecialInvalid:
- case ConstPtrSpecialDiscard:
- zig_unreachable();
- case ConstPtrSpecialRef:
- init_const_ptr_ref(ira->codegen, ptr_val,
- parent_ptr->data.x_ptr.data.ref.pointee, slice_is_const(return_type));
- break;
- case ConstPtrSpecialBaseArray:
- zig_unreachable();
- case ConstPtrSpecialBaseStruct:
- zig_panic("TODO");
- case ConstPtrSpecialHardCodedAddr:
- init_const_ptr_hard_coded_addr(ira->codegen, ptr_val,
- parent_ptr->type->data.pointer.child_type,
- parent_ptr->data.x_ptr.data.hard_coded_addr.addr + start_scalar,
- slice_is_const(return_type));
- }
+ } else if (ptr_is_undef) {
+ ptr_val->type = get_pointer_to_type(ira->codegen, parent_ptr->type->data.pointer.child_type,
+ slice_is_const(return_type));
+ ptr_val->special = ConstValSpecialUndef;
+ } else switch (parent_ptr->data.x_ptr.special) {
+ case ConstPtrSpecialInvalid:
+ case ConstPtrSpecialDiscard:
+ zig_unreachable();
+ case ConstPtrSpecialRef:
+ init_const_ptr_ref(ira->codegen, ptr_val,
+ parent_ptr->data.x_ptr.data.ref.pointee, slice_is_const(return_type));
+ break;
+ case ConstPtrSpecialBaseArray:
+ zig_unreachable();
+ case ConstPtrSpecialBaseStruct:
+ zig_panic("TODO");
+ case ConstPtrSpecialHardCodedAddr:
+ init_const_ptr_hard_coded_addr(ira->codegen, ptr_val,
+ parent_ptr->type->data.pointer.child_type,
+ parent_ptr->data.x_ptr.data.hard_coded_addr.addr + start_scalar,
+ slice_is_const(return_type));
}
ConstExprValue *len_val = &out_val->data.x_struct.fields[slice_len_index];
std/mem.zig
@@ -42,6 +42,9 @@ pub const Allocator = struct {
fn alignedAlloc(self: &Allocator, comptime T: type, comptime alignment: u29,
n: usize) ![]align(alignment) T
{
+ if (n == 0) {
+ return (&align(alignment) T)(undefined)[0..0];
+ }
const byte_count = math.mul(usize, @sizeOf(T), n) catch return Error.OutOfMemory;
const byte_slice = try self.allocFn(self, byte_count, alignment);
assert(byte_slice.len == byte_count);
@@ -62,6 +65,10 @@ pub const Allocator = struct {
if (old_mem.len == 0) {
return self.alloc(T, n);
}
+ if (n == 0) {
+ self.free(old_mem);
+ return (&align(alignment) T)(undefined)[0..0];
+ }
const old_byte_slice = ([]u8)(old_mem);
const byte_count = math.mul(usize, @sizeOf(T), n) catch return Error.OutOfMemory;
test/cases/eval.zig
@@ -388,3 +388,10 @@ test "string literal used as comptime slice is memoized" {
comptime assert(TypeWithCompTimeSlice(a).Node == TypeWithCompTimeSlice(b).Node);
comptime assert(TypeWithCompTimeSlice("link").Node == TypeWithCompTimeSlice("link").Node);
}
+
+test "comptime slice of undefined pointer of length 0" {
+ const slice1 = (&i32)(undefined)[0..0];
+ assert(slice1.len == 0);
+ const slice2 = (&i32)(undefined)[100..100];
+ assert(slice2.len == 0);
+}
test/compile_errors.zig
@@ -1,6 +1,13 @@
const tests = @import("tests.zig");
pub fn addCases(cases: &tests.CompileErrorContext) void {
+ cases.add("comptime slice of undefined pointer non-zero len",
+ \\export fn entry() void {
+ \\ const slice = (&i32)(undefined)[0..1];
+ \\}
+ ,
+ ".tmp_source.zig:2:36: error: non-zero length slice of undefined pointer");
+
cases.add("type checking function pointers",
\\fn a(b: fn (&const u8) void) void {
\\ b('a');