s390: Fix infcalls passing a single-field struct with static members

The infcall-nested-structs test case yields 36 FAILs on s390x because GCC
and GDB disagree on how to pass a C++ struct like this as an argument to a
function:

  struct s { float x; static float y; };

For the purpose of argument passing, GCC ignores static fields, while GDB
does not.  Thus GCC passes the argument in a floating-point register and
GDB passes it via memory.

Fix this by explicitly ignoring static fields when detecting single-field
structs.

gdb/ChangeLog:

	* s390-tdep.c (s390_effective_inner_type): Ignore static fields
	when unwrapping single-field structs.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c6fff16af40cff62fa9bbda87b89363c69b329bc..21d5233f5bbd8a36a0ed9809643ddceb33b2163e 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2019-10-15  Andreas Arnez  <arnez@linux.ibm.com>
+
+       * s390-tdep.c (s390_effective_inner_type): Ignore static fields
+       when unwrapping single-field structs.
+
 2019-10-14  Simon Marchi  <simon.marchi@polymtl.ca>
 
        * dwarf2read.c: Remove includes.

diff --git a/gdb/s390-tdep.c b/gdb/s390-tdep.c
index e7f1215e1aec7792509fd23eb4e95cc5bfdc4f02..6bd0528cf44584b01af9cabd4f47e69b08b41e63 100644 (file)
--- a/gdb/s390-tdep.c
+++ b/gdb/s390-tdep.c
@@ -1637,11 +1637,26 @@ s390_address_class_name_to_type_flags (struct gdbarch *gdbarch,
 static struct type *
 s390_effective_inner_type (struct type *type, unsigned int min_size)
 {
-  while (TYPE_CODE (type) == TYPE_CODE_STRUCT
-        && TYPE_NFIELDS (type) == 1)
+  while (TYPE_CODE (type) == TYPE_CODE_STRUCT)
     {
-      struct type *inner = check_typedef (TYPE_FIELD_TYPE (type, 0));
+      struct type *inner = NULL;
 
+      /* Find a non-static field, if any.  Unless there's exactly one,
+        abort the unwrapping.  */
+      for (int i = 0; i < TYPE_NFIELDS (type); i++)
+       {
+         struct field f = TYPE_FIELD (type, i);
+
+         if (field_is_static (&f))
+           continue;
+         if (inner != NULL)
+           return type;
+         inner = FIELD_TYPE (f);
+       }
+
+      if (inner == NULL)
+       break;
+      inner = check_typedef (inner);
       if (TYPE_LENGTH (inner) < min_size)
        break;
       type = inner;