--- /dev/null
+/* Function return value location for S/390 ABI.
+ Copyright (C) 2006 Red Hat, Inc.
+
+ This program is Open Source software; you can redistribute it and/or
+ modify it under the terms of the Open Software License version 1.0 as
+ published by the Open Source Initiative.
+
+ You should have received a copy of the Open Software License along
+ with this program; if not, you may obtain a copy of the Open Software
+ License version 1.0 from http://www.opensource.org/licenses/osl.php or
+ by writing the Open Source Initiative c/o Lawrence Rosen, Esq.,
+ 3001 King Ranch Road, Ukiah, CA 95482. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <assert.h>
+#include <dwarf.h>
+
+#define BACKEND s390_
+#include "libebl_CPU.h"
+
+
+/* %r2, or pair %r2, %r3. */
+static const Dwarf_Op loc_intreg[] =
+ {
+ { .atom = DW_OP_reg2 }, { .atom = DW_OP_piece, .number = 4 },
+ { .atom = DW_OP_reg3 }, { .atom = DW_OP_piece, .number = 4 },
+ };
+#define nloc_intreg 1
+#define nloc_intregpair 4
+
+/* %f0. */
+static const Dwarf_Op loc_fpreg[] =
+ {
+ { .atom = DW_OP_reg16 },
+ };
+#define nloc_fpreg 1
+
+/* The return value is a structure and is actually stored in stack space
+ passed in a hidden argument by the caller. But, the compiler
+ helpfully returns the address of that space in %r2. */
+static const Dwarf_Op loc_aggregate[] =
+ {
+ { .atom = DW_OP_breg2, .number = 0 }
+ };
+#define nloc_aggregate 1
+
+
+int
+s390_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
+{
+ /* Start with the function's type, and get the DW_AT_type attribute,
+ which is the type of the return value. */
+
+ Dwarf_Attribute attr_mem;
+ Dwarf_Attribute *attr = dwarf_attr (functypedie, DW_AT_type, &attr_mem);
+ if (attr == NULL)
+ /* The function has no return value, like a `void' function in C. */
+ return 0;
+
+ Dwarf_Die die_mem;
+ Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
+ int tag = dwarf_tag (typedie);
+
+ /* Follow typedefs and qualifiers to get to the actual type. */
+ while (tag == DW_TAG_typedef
+ || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type
+ || tag == DW_TAG_restrict_type || tag == DW_TAG_mutable_type)
+ {
+ attr = dwarf_attr (typedie, DW_AT_type, &attr_mem);
+ typedie = dwarf_formref_die (attr, &die_mem);
+ tag = dwarf_tag (typedie);
+ }
+
+ Dwarf_Word size;
+ switch (tag)
+ {
+ case -1:
+ return -1;
+
+ case DW_TAG_subrange_type:
+ if (! dwarf_hasattr (typedie, DW_AT_byte_size))
+ {
+ attr = dwarf_attr (typedie, DW_AT_type, &attr_mem);
+ typedie = dwarf_formref_die (attr, &die_mem);
+ tag = dwarf_tag (typedie);
+ }
+ /* Fall through. */
+
+ case DW_TAG_base_type:
+ case DW_TAG_enumeration_type:
+ case DW_TAG_pointer_type:
+ case DW_TAG_ptr_to_member_type:
+ {
+ Dwarf_Die cudie;
+ uint8_t asize;
+ if (dwarf_diecu (typedie, &cudie, &asize, NULL) == NULL)
+ return -1;
+
+ if (dwarf_formudata (dwarf_attr (typedie, DW_AT_byte_size,
+ &attr_mem), &size) != 0)
+ {
+ if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
+ size = asize;
+ else
+ return -1;
+ }
+ if (tag == DW_TAG_base_type)
+ {
+ Dwarf_Word encoding;
+ if (dwarf_formudata (dwarf_attr (typedie, DW_AT_encoding,
+ &attr_mem), &encoding) != 0)
+ return -1;
+ if (encoding == DW_ATE_float && size <= 8)
+ {
+ *locp = loc_fpreg;
+ return nloc_fpreg;
+ }
+ }
+ if (size <= 8)
+ {
+ *locp = loc_intreg;
+ return size <= asize ? nloc_intreg : nloc_intregpair;
+ }
+ }
+ /* Fall through. */
+
+ case DW_TAG_structure_type:
+ case DW_TAG_class_type:
+ case DW_TAG_union_type:
+ case DW_TAG_array_type:
+ *locp = loc_aggregate;
+ return nloc_aggregate;
+ }
+
+ /* XXX We don't have a good way to return specific errors from ebl calls.
+ This value means we do not understand the type, but it is well-formed
+ DWARF and might be valid. */
+ return -2;
+}
projects / thirdparty / elfutils.git / commitdiff
