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stage1: add missing runtime safety for @intCast unsigned -> signed of same bit count

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This commit is contained in:
xackus 2020-07-05 17:58:21 +02:00
parent 0ae1157e45
commit 51f8c306d9
2 changed files with 16 additions and 4 deletions
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10
src/codegen.cpp
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@ -1535,9 +1535,11 @@ static LLVMValueRef gen_widen_or_shorten(CodeGen *g, bool want_runtime_safety, Z
zig_unreachable();
}
if (actual_type->id == ZigTypeIdInt &&
!wanted_type->data.integral.is_signed && actual_type->data.integral.is_signed &&
want_runtime_safety)
if (actual_type->id == ZigTypeIdInt && want_runtime_safety && (
// negative to unsigned
(!wanted_type->data.integral.is_signed && actual_type->data.integral.is_signed) ||
// unsigned would become negative
(wanted_type->data.integral.is_signed && !actual_type->data.integral.is_signed && actual_bits == wanted_bits)))
{
LLVMValueRef zero = LLVMConstNull(get_llvm_type(g, actual_type));
LLVMValueRef ok_bit = LLVMBuildICmp(g->builder, LLVMIntSGE, expr_val, zero, "");
@ -1547,7 +1549,7 @@ static LLVMValueRef gen_widen_or_shorten(CodeGen *g, bool want_runtime_safety, Z
LLVMBuildCondBr(g->builder, ok_bit, ok_block, fail_block);
LLVMPositionBuilderAtEnd(g->builder, fail_block);
gen_safety_crash(g, PanicMsgIdCastNegativeToUnsigned);
gen_safety_crash(g, actual_type->data.integral.is_signed ? PanicMsgIdCastNegativeToUnsigned : PanicMsgIdCastTruncatedData);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
}

10
test/runtime_safety.zig
View File

@ -757,6 +757,16 @@ pub fn addCases(cases: *tests.CompareOutputContext) void {
\\}
);
cases.addRuntimeSafety("unsigned integer not fitting in cast to signed integer - same bit count",
\\pub fn panic(message: []const u8, stack_trace: ?*@import("builtin").StackTrace) noreturn {
\\ @import("std").os.exit(126);
\\}
\\pub fn main() void {
\\ var value: u8 = 245;
\\ var casted = @intCast(i8, value);
\\}
);
cases.addRuntimeSafety("unwrap error",
\\pub fn panic(message: []const u8, stack_trace: ?*@import("builtin").StackTrace) noreturn {
\\ if (@import("std").mem.eql(u8, message, "attempt to unwrap error: Whatever")) {