[FFI/Jreg_JDK21] Fix the issue with the nested struct in libffi

The change simply adopts the fix at libffi/libffi#805 to resolve the the issue with the nested struct in libffi on AIX. Related: #18287 Signed-off-by: ChengJin01 <jincheng@ca.ibm.com>
eclipse-openj9 · Nov 13, 2023 · d20515b · d20515b
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diff --git a/longabout.html b/longabout.html
@@ -167,7 +167,7 @@ <h4>MurmurHash3</h4>
 Note - The x86 and x64 versions do _not_ produce the same results, as the algorithms are optimized for their respective platforms. You can still compile and run any of them on any platform, but your performance with the non-native version will be less than optimal
 <p>
 <h4>libFFI pre 3.5</h4>
-libffi - Copyright (c) 1996-2022  Anthony Green, Red Hat, Inc and others.
+libffi - Copyright (c) 1996-2023  Anthony Green, Red Hat, Inc and others.
 See source files for details.
 <p>
 Permission is hereby granted, free of charge, to any person obtaining

diff --git a/runtime/include/about.html b/runtime/include/about.html
@@ -85,7 +85,7 @@ <h3>libffi pre 3.5</h3>
 
 <p>The software is modified from the original version.</p>
 
-<p>libffi - Copyright (c) 1996-2022  Anthony Green, Red Hat, Inc and others.</p>
+<p>libffi - Copyright (c) 1996-2023  Anthony Green, Red Hat, Inc and others.</p>
 
 <p>
 Permission is hereby granted, free of charge, to any person obtaining

diff --git a/runtime/libffi/about.html b/runtime/libffi/about.html
@@ -6,7 +6,7 @@
 <body lang="EN-US">
 <h2>About This Content</h2>
 
-<p><em>Mar 14, 2022</em></p>
+<p><em>Nov 13, 2023</em></p>
 <h3>License</h3>
 
 <p>This program and the accompanying materials are made available under the terms of the
@@ -46,7 +46,7 @@ <h3>libFFI pre 3.5</h3>
 
 <p>The software is modified from the original version.</p>
 
-<p>libffi - Copyright (c) 1996-2022  Anthony Green, Red Hat, Inc and others.</p>
+<p>libffi - Copyright (c) 1996-2023  Anthony Green, Red Hat, Inc and others.</p>
 
 <p>
 Permission is hereby granted, free of charge, to any person obtaining

diff --git a/runtime/libffi/powerpc/ffi_darwin.c b/runtime/libffi/powerpc/ffi_darwin.c
@@ -623,38 +623,50 @@ darwin_adjust_aggregate_sizes (ffi_type *s)
 }
 
 /* Adjust the size of S to be correct for AIX.
-   Word-align double unless it is the first member of a structure.  */
+   Word-align double unless it is the first member of a structure recursively.
+   Return non-zero if we found a recursive first member aggregate of interest. */
 
-static void
-aix_adjust_aggregate_sizes (ffi_type *s)
+static int
+aix_adjust_aggregate_sizes (ffi_type *s, int outer_most_type_or_first_member)
 {
-  int i;
+  int i, nested_first_member=0, final_align, rc=0;
 
   if (s->type != FFI_TYPE_STRUCT)
-    return;
+    return 0;
 
   s->size = 0;
   for (i = 0; s->elements[i] != NULL; i++)
     {
-      ffi_type *p;
+      ffi_type p;
       int align;
-
-      p = s->elements[i];
-      aix_adjust_aggregate_sizes (p);
-      align = p->alignment;
-      if (i != 0 && p->type == FFI_TYPE_DOUBLE)
-	align = 4;
-      s->size = FFI_ALIGN(s->size, align) + p->size;
+
+      /* nested aggregates layout differently on AIX, so take a copy of the type */
+      p = *(s->elements[i]);
+      if (i == 0)
+        nested_first_member = aix_adjust_aggregate_sizes(&p, outer_most_type_or_first_member);
+      else
+        aix_adjust_aggregate_sizes(&p, 0);
+      align = p.alignment;
+      if (i != 0 && p.type == FFI_TYPE_DOUBLE)
+        align = 4;
+      s->size = FFI_ALIGN(s->size, align) + p.size;
     }
-
-  s->size = FFI_ALIGN(s->size, s->alignment);
-
-  if (s->elements[0]->type == FFI_TYPE_UINT64
-      || s->elements[0]->type == FFI_TYPE_SINT64
-      || s->elements[0]->type == FFI_TYPE_DOUBLE
-      || s->elements[0]->alignment == 8)
-    s->alignment = s->alignment > 8 ? s->alignment : 8;
-  /* Do not add additional tail padding.  */
+
+  final_align=s->alignment;
+  if ((s->elements[0]->type == FFI_TYPE_UINT64
+          || s->elements[0]->type == FFI_TYPE_SINT64
+          || s->elements[0]->type == FFI_TYPE_DOUBLE
+          || s->elements[0]->alignment == 8 || nested_first_member)) {
+      final_align = s->alignment > 8 ? s->alignment : 8;
+      rc=1;
+      /* still use the adjusted alignment to calculate tail padding, but don't adjust the types alignment if
+         we aren't in the recursive first position */
+      if (outer_most_type_or_first_member)
+        s->alignment=final_align;
+  }
+
+  s->size = FFI_ALIGN(s->size, final_align);
+  return rc;
 }
 
 /* Perform machine dependent cif processing.  */
@@ -682,9 +694,9 @@ ffi_prep_cif_machdep (ffi_cif *cif)
 
   if (cif->abi == FFI_AIX)
     {
-      aix_adjust_aggregate_sizes (cif->rtype);
+      aix_adjust_aggregate_sizes (cif->rtype, 1);
       for (i = 0; i < cif->nargs; i++)
-	aix_adjust_aggregate_sizes (cif->arg_types[i]);
+	aix_adjust_aggregate_sizes (cif->arg_types[i], 1);
     }
 
   /* Space for the frame pointer, callee's LR, CR, etc, and for