Commit 59de24817e
Changed files (6)
src/all_types.hpp
@@ -1488,6 +1488,7 @@ enum PanicMsgId {
PanicMsgIdBadUnionField,
PanicMsgIdBadEnumValue,
PanicMsgIdFloatToInt,
+ PanicMsgIdPtrCastNull,
PanicMsgIdCount,
};
@@ -3001,12 +3002,14 @@ struct IrInstructionPtrCastSrc {
IrInstruction *dest_type;
IrInstruction *ptr;
+ bool safety_check_on;
};
struct IrInstructionPtrCastGen {
IrInstruction base;
IrInstruction *ptr;
+ bool safety_check_on;
};
struct IrInstructionBitCast {
src/analyze.cpp
@@ -6902,3 +6902,12 @@ const char *container_string(ContainerKind kind) {
}
zig_unreachable();
}
+
+bool ptr_allows_addr_zero(ZigType *ptr_type) {
+ if (ptr_type->id == ZigTypeIdPointer) {
+ return ptr_type->data.pointer.allow_zero;
+ } else if (ptr_type->id == ZigTypeIdOptional) {
+ return true;
+ }
+ return false;
+}
src/analyze.hpp
@@ -45,6 +45,7 @@ void find_libc_lib_path(CodeGen *g);
bool type_has_bits(ZigType *type_entry);
bool type_allowed_in_extern(CodeGen *g, ZigType *type_entry);
+bool ptr_allows_addr_zero(ZigType *ptr_type);
ImportTableEntry *add_source_file(CodeGen *g, PackageTableEntry *package, Buf *abs_full_path, Buf *source_code);
src/codegen.cpp
@@ -950,6 +950,8 @@ static Buf *panic_msg_buf(PanicMsgId msg_id) {
return buf_create_from_str("invalid enum value");
case PanicMsgIdFloatToInt:
return buf_create_from_str("integer part of floating point value out of bounds");
+ case PanicMsgIdPtrCastNull:
+ return buf_create_from_str("cast causes pointer to be null");
}
zig_unreachable();
}
@@ -3028,7 +3030,22 @@ static LLVMValueRef ir_render_ptr_cast(CodeGen *g, IrExecutable *executable,
return nullptr;
}
LLVMValueRef ptr = ir_llvm_value(g, instruction->ptr);
- return LLVMBuildBitCast(g->builder, ptr, wanted_type->type_ref, "");
+ LLVMValueRef result_ptr = LLVMBuildBitCast(g->builder, ptr, wanted_type->type_ref, "");
+ bool want_safety_check = instruction->safety_check_on && ir_want_runtime_safety(g, &instruction->base);
+ if (!want_safety_check || ptr_allows_addr_zero(wanted_type))
+ return result_ptr;
+
+ LLVMValueRef zero = LLVMConstNull(LLVMTypeOf(result_ptr));
+ LLVMValueRef ok_bit = LLVMBuildICmp(g->builder, LLVMIntNE, result_ptr, zero, "");
+ LLVMBasicBlockRef fail_block = LLVMAppendBasicBlock(g->cur_fn_val, "PtrCastFail");
+ LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "PtrCastOk");
+ LLVMBuildCondBr(g->builder, ok_bit, ok_block, fail_block);
+
+ LLVMPositionBuilderAtEnd(g->builder, fail_block);
+ gen_safety_crash(g, PanicMsgIdPtrCastNull);
+
+ LLVMPositionBuilderAtEnd(g->builder, ok_block);
+ return result_ptr;
}
static LLVMValueRef ir_render_bit_cast(CodeGen *g, IrExecutable *executable,
src/ir.cpp
@@ -172,7 +172,7 @@ static void buf_write_value_bytes(CodeGen *codegen, uint8_t *buf, ConstExprValue
static Error ir_read_const_ptr(IrAnalyze *ira, CodeGen *codegen, AstNode *source_node,
ConstExprValue *out_val, ConstExprValue *ptr_val);
static IrInstruction *ir_analyze_ptr_cast(IrAnalyze *ira, IrInstruction *source_instr, IrInstruction *ptr,
- ZigType *dest_type, IrInstruction *dest_type_src);
+ ZigType *dest_type, IrInstruction *dest_type_src, bool safety_check_on);
static ConstExprValue *ir_resolve_const(IrAnalyze *ira, IrInstruction *value, UndefAllowed undef_allowed);
static void copy_const_val(ConstExprValue *dest, ConstExprValue *src, bool same_global_refs);
static Error resolve_ptr_align(IrAnalyze *ira, ZigType *ty, uint32_t *result_align);
@@ -2202,12 +2202,13 @@ static IrInstruction *ir_build_test_comptime(IrBuilder *irb, Scope *scope, AstNo
}
static IrInstruction *ir_build_ptr_cast_src(IrBuilder *irb, Scope *scope, AstNode *source_node,
- IrInstruction *dest_type, IrInstruction *ptr)
+ IrInstruction *dest_type, IrInstruction *ptr, bool safety_check_on)
{
IrInstructionPtrCastSrc *instruction = ir_build_instruction<IrInstructionPtrCastSrc>(
irb, scope, source_node);
instruction->dest_type = dest_type;
instruction->ptr = ptr;
+ instruction->safety_check_on = safety_check_on;
ir_ref_instruction(dest_type, irb->current_basic_block);
ir_ref_instruction(ptr, irb->current_basic_block);
@@ -2216,12 +2217,13 @@ static IrInstruction *ir_build_ptr_cast_src(IrBuilder *irb, Scope *scope, AstNod
}
static IrInstruction *ir_build_ptr_cast_gen(IrAnalyze *ira, IrInstruction *source_instruction,
- ZigType *ptr_type, IrInstruction *ptr)
+ ZigType *ptr_type, IrInstruction *ptr, bool safety_check_on)
{
IrInstructionPtrCastGen *instruction = ir_build_instruction<IrInstructionPtrCastGen>(
&ira->new_irb, source_instruction->scope, source_instruction->source_node);
instruction->base.value.type = ptr_type;
instruction->ptr = ptr;
+ instruction->safety_check_on = safety_check_on;
ir_ref_instruction(ptr, ira->new_irb.current_basic_block);
@@ -4505,7 +4507,7 @@ static IrInstruction *ir_gen_builtin_fn_call(IrBuilder *irb, Scope *scope, AstNo
if (arg1_value == irb->codegen->invalid_instruction)
return arg1_value;
- IrInstruction *ptr_cast = ir_build_ptr_cast_src(irb, scope, node, arg0_value, arg1_value);
+ IrInstruction *ptr_cast = ir_build_ptr_cast_src(irb, scope, node, arg0_value, arg1_value, true);
return ir_lval_wrap(irb, scope, ptr_cast, lval);
}
case BuiltinFnIdBitCast:
@@ -6740,7 +6742,8 @@ static IrInstruction *ir_gen_cancel_target(IrBuilder *irb, Scope *scope, AstNode
IrInstruction *is_suspended_mask = ir_build_const_usize(irb, scope, node, 0x2); // 0b010
// TODO relies on Zig not re-ordering fields
- IrInstruction *casted_target_inst = ir_build_ptr_cast_src(irb, scope, node, promise_T_type_val, target_inst);
+ IrInstruction *casted_target_inst = ir_build_ptr_cast_src(irb, scope, node, promise_T_type_val, target_inst,
+ false);
IrInstruction *coro_promise_ptr = ir_build_coro_promise(irb, scope, node, casted_target_inst);
Buf *atomic_state_field_name = buf_create_from_str(ATOMIC_STATE_FIELD_NAME);
IrInstruction *atomic_state_ptr = ir_build_field_ptr(irb, scope, node, coro_promise_ptr,
@@ -6818,7 +6821,8 @@ static IrInstruction *ir_gen_resume_target(IrBuilder *irb, Scope *scope, AstNode
get_promise_type(irb->codegen, irb->codegen->builtin_types.entry_void));
// TODO relies on Zig not re-ordering fields
- IrInstruction *casted_target_inst = ir_build_ptr_cast_src(irb, scope, node, promise_T_type_val, target_inst);
+ IrInstruction *casted_target_inst = ir_build_ptr_cast_src(irb, scope, node, promise_T_type_val, target_inst,
+ false);
IrInstruction *coro_promise_ptr = ir_build_coro_promise(irb, scope, node, casted_target_inst);
Buf *atomic_state_field_name = buf_create_from_str(ATOMIC_STATE_FIELD_NAME);
IrInstruction *atomic_state_ptr = ir_build_field_ptr(irb, scope, node, coro_promise_ptr,
@@ -7363,7 +7367,8 @@ bool ir_gen(CodeGen *codegen, AstNode *node, Scope *scope, IrExecutable *ir_exec
u8_ptr_type = ir_build_const_type(irb, coro_scope, node,
get_pointer_to_type(irb->codegen, irb->codegen->builtin_types.entry_u8, false));
- IrInstruction *promise_as_u8_ptr = ir_build_ptr_cast_src(irb, coro_scope, node, u8_ptr_type, coro_promise_ptr);
+ IrInstruction *promise_as_u8_ptr = ir_build_ptr_cast_src(irb, coro_scope, node, u8_ptr_type,
+ coro_promise_ptr, false);
coro_id = ir_build_coro_id(irb, coro_scope, node, promise_as_u8_ptr);
coro_size_var = ir_create_var(irb, node, coro_scope, nullptr, false, false, true, const_bool_false);
IrInstruction *coro_size = ir_build_coro_size(irb, coro_scope, node);
@@ -7387,7 +7392,8 @@ bool ir_gen(CodeGen *codegen, AstNode *node, Scope *scope, IrExecutable *ir_exec
ir_build_return(irb, coro_scope, node, undef);
ir_set_cursor_at_end_and_append_block(irb, alloc_ok_block);
- IrInstruction *coro_mem_ptr = ir_build_ptr_cast_src(irb, coro_scope, node, u8_ptr_type, maybe_coro_mem_ptr);
+ IrInstruction *coro_mem_ptr = ir_build_ptr_cast_src(irb, coro_scope, node, u8_ptr_type, maybe_coro_mem_ptr,
+ false);
irb->exec->coro_handle = ir_build_coro_begin(irb, coro_scope, node, coro_id, coro_mem_ptr);
Buf *atomic_state_field_name = buf_create_from_str(ATOMIC_STATE_FIELD_NAME);
@@ -7465,9 +7471,10 @@ bool ir_gen(CodeGen *codegen, AstNode *node, Scope *scope, IrExecutable *ir_exec
get_pointer_to_type_extra(irb->codegen, irb->codegen->builtin_types.entry_u8,
false, false, PtrLenUnknown, 0, 0, 0));
IrInstruction *result_ptr = ir_build_load_ptr(irb, scope, node, irb->exec->coro_result_ptr_field_ptr);
- IrInstruction *result_ptr_as_u8_ptr = ir_build_ptr_cast_src(irb, scope, node, u8_ptr_type_unknown_len, result_ptr);
- IrInstruction *return_value_ptr_as_u8_ptr = ir_build_ptr_cast_src(irb, scope, node, u8_ptr_type_unknown_len,
- irb->exec->coro_result_field_ptr);
+ IrInstruction *result_ptr_as_u8_ptr = ir_build_ptr_cast_src(irb, scope, node, u8_ptr_type_unknown_len,
+ result_ptr, false);
+ IrInstruction *return_value_ptr_as_u8_ptr = ir_build_ptr_cast_src(irb, scope, node,
+ u8_ptr_type_unknown_len, irb->exec->coro_result_field_ptr, false);
IrInstruction *return_type_inst = ir_build_const_type(irb, scope, node,
fn_entry->type_entry->data.fn.fn_type_id.return_type);
IrInstruction *size_of_ret_val = ir_build_size_of(irb, scope, node, return_type_inst);
@@ -7517,7 +7524,8 @@ bool ir_gen(CodeGen *codegen, AstNode *node, Scope *scope, IrExecutable *ir_exec
IrInstruction *u8_ptr_type_unknown_len = ir_build_const_type(irb, scope, node,
get_pointer_to_type_extra(irb->codegen, irb->codegen->builtin_types.entry_u8,
false, false, PtrLenUnknown, 0, 0, 0));
- IrInstruction *coro_mem_ptr = ir_build_ptr_cast_src(irb, scope, node, u8_ptr_type_unknown_len, coro_mem_ptr_maybe);
+ IrInstruction *coro_mem_ptr = ir_build_ptr_cast_src(irb, scope, node, u8_ptr_type_unknown_len,
+ coro_mem_ptr_maybe, false);
IrInstruction *coro_mem_ptr_ref = ir_build_ref(irb, scope, node, coro_mem_ptr, true, false);
IrInstruction *coro_size_ptr = ir_build_var_ptr(irb, scope, node, coro_size_var);
IrInstruction *coro_size = ir_build_load_ptr(irb, scope, node, coro_size_ptr);
@@ -8644,15 +8652,6 @@ static ZigType *get_error_set_intersection(IrAnalyze *ira, ZigType *set1, ZigTyp
return err_set_type;
}
-static bool ptr_allows_addr_zero(ZigType *ptr_type) {
- if (ptr_type->id == ZigTypeIdPointer) {
- return ptr_type->data.pointer.allow_zero;
- } else if (ptr_type->id == ZigTypeIdOptional) {
- return true;
- }
- return false;
-}
-
static ConstCastOnly types_match_const_cast_only(IrAnalyze *ira, ZigType *wanted_type,
ZigType *actual_type, AstNode *source_node, bool wanted_is_mutable)
{
@@ -11310,7 +11309,7 @@ static IrInstruction *ir_analyze_cast(IrAnalyze *ira, IrInstruction *source_inst
actual_type->data.pointer.host_int_bytes == dest_ptr_type->data.pointer.host_int_bytes &&
get_ptr_align(ira->codegen, actual_type) >= get_ptr_align(ira->codegen, dest_ptr_type))
{
- return ir_analyze_ptr_cast(ira, source_instr, value, wanted_type, source_instr);
+ return ir_analyze_ptr_cast(ira, source_instr, value, wanted_type, source_instr, true);
}
}
@@ -11352,7 +11351,7 @@ static IrInstruction *ir_analyze_cast(IrAnalyze *ira, IrInstruction *source_inst
actual_type->data.pointer.child_type, source_node,
!wanted_type->data.pointer.is_const).id == ConstCastResultIdOk)
{
- return ir_analyze_ptr_cast(ira, source_instr, value, wanted_type, source_instr);
+ return ir_analyze_ptr_cast(ira, source_instr, value, wanted_type, source_instr, true);
}
// cast from integer to C pointer
@@ -20616,7 +20615,7 @@ static IrInstruction *ir_align_cast(IrAnalyze *ira, IrInstruction *target, uint3
}
static IrInstruction *ir_analyze_ptr_cast(IrAnalyze *ira, IrInstruction *source_instr, IrInstruction *ptr,
- ZigType *dest_type, IrInstruction *dest_type_src)
+ ZigType *dest_type, IrInstruction *dest_type_src, bool safety_check_on)
{
Error err;
@@ -20685,7 +20684,7 @@ static IrInstruction *ir_analyze_ptr_cast(IrAnalyze *ira, IrInstruction *source_
return ira->codegen->invalid_instruction;
}
- IrInstruction *casted_ptr = ir_build_ptr_cast_gen(ira, source_instr, dest_type, ptr);
+ IrInstruction *casted_ptr = ir_build_ptr_cast_gen(ira, source_instr, dest_type, ptr, safety_check_on);
if (type_has_bits(dest_type) && !type_has_bits(src_type)) {
ErrorMsg *msg = ir_add_error(ira, source_instr,
@@ -20722,7 +20721,8 @@ static IrInstruction *ir_analyze_instruction_ptr_cast(IrAnalyze *ira, IrInstruct
if (type_is_invalid(src_type))
return ira->codegen->invalid_instruction;
- return ir_analyze_ptr_cast(ira, &instruction->base, ptr, dest_type, dest_type_value);
+ return ir_analyze_ptr_cast(ira, &instruction->base, ptr, dest_type, dest_type_value,
+ instruction->safety_check_on);
}
static void buf_write_value_bytes_array(CodeGen *codegen, uint8_t *buf, ConstExprValue *val, size_t len) {
test/runtime_safety.zig
@@ -1,6 +1,16 @@
const tests = @import("tests.zig");
pub fn addCases(cases: *tests.CompareOutputContext) void {
+ cases.addRuntimeSafety("pointer casting null to non-optional pointer",
+ \\pub fn panic(message: []const u8, stack_trace: ?*@import("builtin").StackTrace) noreturn {
+ \\ @import("std").os.exit(126);
+ \\}
+ \\pub fn main() void {
+ \\ var c_ptr: [*c]u8 = 0;
+ \\ var zig_ptr: *u8 = c_ptr;
+ \\}
+ );
+
cases.addRuntimeSafety("@intToEnum - no matching tag value",
\\pub fn panic(message: []const u8, stack_trace: ?*@import("builtin").StackTrace) noreturn {
\\ @import("std").os.exit(126);