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implement allowzero pointer attribute

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closes #1953

only needed for freestanding targets.

also adds safety for `@intToPtr` when the address is zero.
This commit is contained in:
Andrew Kelley
2019-03-25 12:55:45 -04:00
parent 3306e43984
commit 5eaead6a56
18 changed files with 225 additions and 78 deletions
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31
src/codegen.cpp
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@@ -956,7 +956,7 @@ static LLVMValueRef get_panic_msg_ptr_val(CodeGen *g, PanicMsgId msg_id) {
}
ZigType *u8_ptr_type = get_pointer_to_type_extra(g, g->builtin_types.entry_u8, true, false,
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0);
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0, false);
ZigType *str_type = get_slice_type(g, u8_ptr_type);
return LLVMConstBitCast(val->global_refs->llvm_global, LLVMPointerType(str_type->type_ref, 0));
}
@@ -1515,7 +1515,7 @@ static LLVMValueRef get_safety_crash_err_fn(CodeGen *g) {
ZigType *u8_ptr_type = get_pointer_to_type_extra(g, g->builtin_types.entry_u8, true, false,
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0);
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0, false);
ZigType *str_type = get_slice_type(g, u8_ptr_type);
LLVMValueRef global_slice_fields[] = {
full_buf_ptr,
@@ -3103,6 +3103,18 @@ static LLVMValueRef ir_render_widen_or_shorten(CodeGen *g, IrExecutable *executa
static LLVMValueRef ir_render_int_to_ptr(CodeGen *g, IrExecutable *executable, IrInstructionIntToPtr *instruction) {
ZigType *wanted_type = instruction->base.value.type;
LLVMValueRef target_val = ir_llvm_value(g, instruction->target);
if (!ptr_allows_addr_zero(wanted_type) && ir_want_runtime_safety(g, &instruction->base)) {
LLVMValueRef zero = LLVMConstNull(LLVMTypeOf(target_val));
LLVMValueRef is_zero_bit = LLVMBuildICmp(g->builder, LLVMIntEQ, target_val, zero, "");
LLVMBasicBlockRef bad_block = LLVMAppendBasicBlock(g->cur_fn_val, "PtrToIntBad");
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "PtrToIntOk");
LLVMBuildCondBr(g->builder, is_zero_bit, bad_block, ok_block);
LLVMPositionBuilderAtEnd(g->builder, bad_block);
gen_safety_crash(g, PanicMsgIdPtrCastNull);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
}
return LLVMBuildIntToPtr(g->builder, target_val, wanted_type->type_ref, "");
}
@@ -3270,7 +3282,7 @@ static LLVMValueRef ir_render_decl_var(CodeGen *g, IrExecutable *executable,
if (have_init_expr) {
ZigType *var_ptr_type = get_pointer_to_type_extra(g, var->var_type, false, false,
PtrLenSingle, var->align_bytes, 0, 0);
PtrLenSingle, var->align_bytes, 0, 0, false);
LLVMValueRef llvm_init_val = ir_llvm_value(g, init_value);
gen_assign_raw(g, var->value_ref, var_ptr_type, llvm_init_val);
} else if (ir_want_runtime_safety(g, &decl_var_instruction->base)) {
@@ -4160,7 +4172,7 @@ static LLVMValueRef get_enum_tag_name_function(CodeGen *g, ZigType *enum_type) {
return enum_type->data.enumeration.name_function;
ZigType *u8_ptr_type = get_pointer_to_type_extra(g, g->builtin_types.entry_u8, false, false,
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0);
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0, false);
ZigType *u8_slice_type = get_slice_type(g, u8_ptr_type);
ZigType *tag_int_type = enum_type->data.enumeration.tag_int_type;
@@ -4953,7 +4965,7 @@ static LLVMValueRef ir_render_struct_init(CodeGen *g, IrExecutable *executable,
ZigType *ptr_type = get_pointer_to_type_extra(g, type_struct_field->type_entry,
false, false, PtrLenSingle, field_align_bytes,
(uint32_t)type_struct_field->bit_offset_in_host, host_int_bytes);
(uint32_t)type_struct_field->bit_offset_in_host, host_int_bytes, false);
gen_assign_raw(g, field_ptr, ptr_type, value);
}
@@ -4969,7 +4981,7 @@ static LLVMValueRef ir_render_union_init(CodeGen *g, IrExecutable *executable, I
uint32_t field_align_bytes = get_abi_alignment(g, type_union_field->type_entry);
ZigType *ptr_type = get_pointer_to_type_extra(g, type_union_field->type_entry,
false, false, PtrLenSingle, field_align_bytes,
0, 0);
0, 0, false);
LLVMValueRef uncasted_union_ptr;
// Even if safety is off in this block, if the union type has the safety field, we have to populate it
@@ -5224,7 +5236,7 @@ static LLVMValueRef get_coro_alloc_helper_fn_val(CodeGen *g, LLVMTypeRef alloc_f
LLVMPositionBuilderAtEnd(g->builder, ok_block);
LLVMValueRef payload_ptr = LLVMBuildStructGEP(g->builder, sret_ptr, err_union_payload_index, "");
ZigType *u8_ptr_type = get_pointer_to_type_extra(g, g->builtin_types.entry_u8, false, false,
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0);
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0, false);
ZigType *slice_type = get_slice_type(g, u8_ptr_type);
size_t ptr_field_index = slice_type->data.structure.fields[slice_ptr_index].gen_index;
LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP(g->builder, payload_ptr, ptr_field_index, "");
@@ -6470,7 +6482,7 @@ static void generate_error_name_table(CodeGen *g) {
assert(g->errors_by_index.length > 0);
ZigType *u8_ptr_type = get_pointer_to_type_extra(g, g->builtin_types.entry_u8, true, false,
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0);
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0, false);
ZigType *str_type = get_slice_type(g, u8_ptr_type);
LLVMValueRef *values = allocate<LLVMValueRef>(g->errors_by_index.length);
@@ -7551,6 +7563,7 @@ Buf *codegen_generate_builtin_source(CodeGen *g) {
" is_volatile: bool,\n"
" alignment: comptime_int,\n"
" child: type,\n"
" is_allowzero: bool,\n"
"\n"
" pub const Size = enum {\n"
" One,\n"
@@ -8158,7 +8171,7 @@ static void create_test_compile_var_and_add_test_runner(CodeGen *g) {
}
ZigType *u8_ptr_type = get_pointer_to_type_extra(g, g->builtin_types.entry_u8, true, false,
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0);
PtrLenUnknown, get_abi_alignment(g, g->builtin_types.entry_u8), 0, 0, false);
ZigType *str_type = get_slice_type(g, u8_ptr_type);
ZigType *fn_type = get_test_fn_type(g);