[powerpc][AIX] fix layout issues for nested struct types #805
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On AIX under the default power alignment rules, the layout
of struct types which are nested inside other structs may
be different than the layout of those types on their own.
Specifically the first member double rules which would
apply an eight byte alignment if that type appears in the
first position of a struct:
1) apply recursively if the struct appear in the first member
of another struct
2) do not apply if that struct is itself a member of another struct
and not the first member.
The current implementation of the rules in libffi doesn't handle these
cases, causing a mismatch with the compiler and causing some crashes
we see when OpenJ9 is used with libffi on AIX.
This PR corrects this and adds some representative test cases.
ChengJin01
pushed a commit
to ChengJin01/openj9
that referenced
this pull request
Oct 27, 2023
The change simply adopts the fix at libffi/libffi#805 to resolve the the issue with the nested struct in libffi on AIX. Signed-off-by: ChengJin01 <jincheng@ca.ibm.com>
|
FYI: @atgreen |
keithc-ca
reviewed
Oct 31, 2023
|
I've made some updates to correctly handle nested structs which have tail padding (and added such a test case) |
ChengJin01
pushed a commit
to ChengJin01/openj9
that referenced
this pull request
Nov 13, 2023
The change simply adopts the fix at libffi/libffi#805 to resolve the the issue with the nested struct in libffi on AIX. Related: eclipse-openj9#18287 Signed-off-by: ChengJin01 <jincheng@ca.ibm.com>
|
Gentle ping |
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On AIX under the default power alignment rules, the layout of struct types which are nested inside other structs may observe different alignment requirements than when we layout of those types on their own, resulting in a different total layout.
Specifically the first member double rules which would apply an eight byte alignment if that type appears in the first position of a struct:
of another struct
and not the first member.
The current implementation of the rules in libffi doesn't handle these cases, causing a mismatch with the compiler and causing some crashes we see when OpenJ9 is used with libffi on AIX.
This PR corrects this and adds some representative test cases.