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error sets: runtime safety for int-to-err and err set cast

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This commit is contained in:
Andrew Kelley
2018-02-08 21:54:44 -05:00
parent 8fc6e31567
commit 54c06bf715
5 changed files with 139 additions and 42 deletions
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79
src/codegen.cpp
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@@ -1958,6 +1958,54 @@ static LLVMValueRef ir_render_bin_op(CodeGen *g, IrExecutable *executable,
zig_unreachable();
}
static void add_error_range_check(CodeGen *g, TypeTableEntry *err_set_type, TypeTableEntry *int_type, LLVMValueRef target_val) {
assert(err_set_type->id == TypeTableEntryIdErrorSet);
if (type_is_global_error_set(err_set_type)) {
LLVMValueRef zero = LLVMConstNull(int_type->type_ref);
LLVMValueRef neq_zero_bit = LLVMBuildICmp(g->builder, LLVMIntNE, target_val, zero, "");
LLVMValueRef ok_bit;
BigInt biggest_possible_err_val = {0};
eval_min_max_value_int(g, int_type, &biggest_possible_err_val, true);
if (bigint_fits_in_bits(&biggest_possible_err_val, 64, false) &&
bigint_as_unsigned(&biggest_possible_err_val) < g->errors_by_index.length)
{
ok_bit = neq_zero_bit;
} else {
LLVMValueRef error_value_count = LLVMConstInt(int_type->type_ref, g->errors_by_index.length, false);
LLVMValueRef in_bounds_bit = LLVMBuildICmp(g->builder, LLVMIntULT, target_val, error_value_count, "");
ok_bit = LLVMBuildAnd(g->builder, neq_zero_bit, in_bounds_bit, "");
}
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "IntToErrOk");
LLVMBasicBlockRef fail_block = LLVMAppendBasicBlock(g->cur_fn_val, "IntToErrFail");
LLVMBuildCondBr(g->builder, ok_bit, ok_block, fail_block);
LLVMPositionBuilderAtEnd(g->builder, fail_block);
gen_safety_crash(g, PanicMsgIdInvalidErrorCode);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
} else {
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "IntToErrOk");
LLVMBasicBlockRef fail_block = LLVMAppendBasicBlock(g->cur_fn_val, "IntToErrFail");
uint32_t err_count = err_set_type->data.error_set.err_count;
LLVMValueRef switch_instr = LLVMBuildSwitch(g->builder, target_val, fail_block, err_count);
for (uint32_t i = 0; i < err_count; i += 1) {
LLVMValueRef case_value = LLVMConstInt(g->err_tag_type->type_ref, err_set_type->data.error_set.errors[i]->value, false);
LLVMAddCase(switch_instr, case_value, ok_block);
}
LLVMPositionBuilderAtEnd(g->builder, fail_block);
gen_safety_crash(g, PanicMsgIdInvalidErrorCode);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
}
}
static LLVMValueRef ir_render_cast(CodeGen *g, IrExecutable *executable,
IrInstructionCast *cast_instruction)
{
@@ -2082,7 +2130,9 @@ static LLVMValueRef ir_render_cast(CodeGen *g, IrExecutable *executable,
assert(actual_type->id == TypeTableEntryIdBool);
return LLVMBuildZExt(g->builder, expr_val, wanted_type->type_ref, "");
case CastOpErrSet:
// TODO runtime safety for error casting
if (ir_want_runtime_safety(g, &cast_instruction->base)) {
add_error_range_check(g, wanted_type, g->err_tag_type, expr_val);
}
return expr_val;
}
zig_unreachable();
@@ -2154,32 +2204,7 @@ static LLVMValueRef ir_render_int_to_err(CodeGen *g, IrExecutable *executable, I
LLVMValueRef target_val = ir_llvm_value(g, instruction->target);
if (ir_want_runtime_safety(g, &instruction->base)) {
LLVMValueRef zero = LLVMConstNull(actual_type->type_ref);
LLVMValueRef neq_zero_bit = LLVMBuildICmp(g->builder, LLVMIntNE, target_val, zero, "");
LLVMValueRef ok_bit;
BigInt biggest_possible_err_val = {0};
eval_min_max_value_int(g, actual_type, &biggest_possible_err_val, true);
if (bigint_fits_in_bits(&biggest_possible_err_val, 64, false) &&
bigint_as_unsigned(&biggest_possible_err_val) < g->errors_by_index.length)
{
ok_bit = neq_zero_bit;
} else {
LLVMValueRef error_value_count = LLVMConstInt(actual_type->type_ref, g->errors_by_index.length, false);
LLVMValueRef in_bounds_bit = LLVMBuildICmp(g->builder, LLVMIntULT, target_val, error_value_count, "");
ok_bit = LLVMBuildAnd(g->builder, neq_zero_bit, in_bounds_bit, "");
}
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn_val, "IntToErrOk");
LLVMBasicBlockRef fail_block = LLVMAppendBasicBlock(g->cur_fn_val, "IntToErrFail");
LLVMBuildCondBr(g->builder, ok_bit, ok_block, fail_block);
LLVMPositionBuilderAtEnd(g->builder, fail_block);
gen_safety_crash(g, PanicMsgIdInvalidErrorCode);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
add_error_range_check(g, wanted_type, actual_type, target_val);
}
return gen_widen_or_shorten(g, false, actual_type, g->err_tag_type, target_val);