Fix segfault on tagged output #175
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Currently, record_output() segfaults when passed a pointer to a tag.
This IR, for example, segfaults on my system:
@example = internal constant [3 x i8] c"hi\00"
define i64 @kernel() #0 {
...
call void @__quantum__rt__tuple_record_output(i64 4, ptr @example)
...
This appears to be because record_output() calls CString.from_raw() on a
pointer not managed by CString[1]. This commit uses CStr.from_ptr()
instead and adds some tests to catch future regressions (hopefully).
[1]: https://doc.rust-lang.org/std/ffi/struct.CString.html#method.from_raw
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@microsoft-github-policy-service agree |
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Here's a full example file, if it's useful for trying to reproduce: ; ModuleID = 'LLVMDialectModule'
source_filename = "LLVMDialectModule"
@tag_ret = internal constant [4 x i8] c"ret\00"
@tag_discarded = internal constant [10 x i8] c"discarded\00"
define i64 @kernel() #0 {
call void @__quantum__rt__initialize(ptr null)
call void @__quantum__qis__h__body(ptr null)
call void @__quantum__qis__cx__body(ptr null, ptr inttoptr (i64 1 to ptr))
call void @__quantum__qis__cx__body(ptr null, ptr inttoptr (i64 2 to ptr))
call void @__quantum__qis__cx__body(ptr null, ptr inttoptr (i64 3 to ptr))
call void @__quantum__qis__cx__body(ptr null, ptr inttoptr (i64 4 to ptr))
call void @__quantum__rt__tuple_record_output(i64 5, ptr @tag_ret)
call void @__quantum__qis__mz__body(ptr null, ptr null)
call void @__quantum__qis__mz__body(ptr inttoptr (i64 1 to ptr), ptr inttoptr (i64 1 to ptr))
call void @__quantum__qis__mz__body(ptr inttoptr (i64 2 to ptr), ptr inttoptr (i64 2 to ptr))
call void @__quantum__qis__mz__body(ptr inttoptr (i64 3 to ptr), ptr inttoptr (i64 3 to ptr))
call void @__quantum__qis__mz__body(ptr inttoptr (i64 4 to ptr), ptr inttoptr (i64 4 to ptr))
call void @__quantum__rt__result_record_output(ptr null, ptr null)
call void @__quantum__rt__result_record_output(ptr inttoptr (i64 1 to ptr), ptr null)
call void @__quantum__rt__result_record_output(ptr inttoptr (i64 2 to ptr), ptr null)
call void @__quantum__rt__result_record_output(ptr inttoptr (i64 3 to ptr), ptr null)
call void @__quantum__rt__result_record_output(ptr inttoptr (i64 4 to ptr), ptr null)
call void @__quantum__rt__tuple_record_output(i64 0, ptr @tag_discarded)
ret i64 0
}
declare void @__quantum__qis__h__body(ptr %0)
declare void @__quantum__qis__cx__body(ptr %0, ptr %1)
declare void @__quantum__rt__initialize(ptr %0)
declare void @__quantum__qis__mz__body(ptr %0, ptr %1)
declare void @__quantum__rt__tuple_record_output(i64 %0, ptr %1)
declare void @__quantum__rt__result_record_output(ptr %0, ptr %1)
attributes #0 = { "entry_point" "output_labeling_schema"="qwerty_v1" "qir_profiles"="base_profile" "required_num_qubits"="5" "required_num_results"="5" }
!llvm.module.flags = !{!0, !1, !2, !3, !4}
!0 = !{i32 2, !"Debug Info Version", i32 3}
!1 = !{i32 1, !"dynamic_qubit_management", i1 false}
!2 = !{i32 1, !"dynamic_result_management", i1 false}
!3 = !{i32 1, !"qir_major_version", i32 1}
!4 = !{i32 1, !"qir_minor_version", i32 0}The |
swernli
reviewed
May 21, 2024
swernli
approved these changes
May 21, 2024
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Currently,
record_output()segfaults when passed a pointer to a tag. This IR, for example, segfaults on my system:This appears to be because
record_output()callsCString.from_raw()on a pointer not managed byCString. This commit usesCStr.from_ptr()instead and adds some tests to catch future regressions (hopefully).I am not a Rust programmer so hopefully I am doing this right. But at least
cargo testpasses for me now (the new tests fail with the existing code) and my example IR file no longer segfaults.