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stage2: runtime safety check intCast signedness

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This commit is contained in:
Mitchell Hashimoto 2022-03-25 16:45:29 -07:00
parent 4ad98d0714
commit 3c91818438
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GPG Key ID: 523D5DC389D273BC
1 changed files with 16 additions and 3 deletions
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19
src/Sema.zig
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@ -6800,7 +6800,7 @@ fn intCast(
}
try sema.requireRuntimeBlock(block, operand_src);
if (runtime_safety) {
if (runtime_safety and block.wantSafety()) {
const target = sema.mod.getTarget();
const operand_ty = sema.typeOf(operand);
const actual_info = operand_ty.intInfo(target);
@ -6808,8 +6808,21 @@ fn intCast(
const actual_bits = actual_info.bits;
const wanted_bits = wanted_info.bits;
// requirement: bitSizeOf(operand) <= bitSizeOf(destination type)
if (actual_bits > wanted_bits) {
// requirement: signed to unsigned >= 0
if (actual_info.signedness == .signed and
wanted_info.signedness == .unsigned)
{
const zero_inst = try sema.addConstant(sema.typeOf(operand), Value.zero);
const is_in_range = try block.addBinOp(.cmp_gte, operand, zero_inst);
try sema.addSafetyCheck(block, is_in_range, .cast_truncated_data);
}
// requirement: unsigned int value fits into target type
if (actual_bits > wanted_bits or
(actual_bits == wanted_bits and
actual_info.signedness == .unsigned and
wanted_info.signedness == .signed))
{
const max_int = try dest_ty.maxInt(sema.arena, target);
const max_int_inst = try sema.addConstant(operand_ty, max_int);
const is_in_range = try block.addBinOp(.cmp_lte, operand, max_int_inst);