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252 lines
6.9 KiB
252 lines
6.9 KiB
/* Function return value location for Linux/RISC-V ABI.
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Copyright (C) 2018 Sifive, Inc.
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Copyright (C) 2013 Red Hat, Inc.
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This file is part of elfutils.
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This file is free software; you can redistribute it and/or modify
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it under the terms of either
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at
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your option) any later version
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or
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* the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at
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your option) any later version
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or both in parallel, as here.
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elfutils is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received copies of the GNU General Public License and
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the GNU Lesser General Public License along with this program. If
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not, see <http://www.gnu.org/licenses/>. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <stdio.h>
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#include <inttypes.h>
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#include <assert.h>
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#include <dwarf.h>
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#define BACKEND riscv_
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#include "libebl_CPU.h"
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static int
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dwarf_bytesize_aux (Dwarf_Die *die, Dwarf_Word *sizep)
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{
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int bits;
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if (((bits = 8 * dwarf_bytesize (die)) < 0
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&& (bits = dwarf_bitsize (die)) < 0)
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|| bits % 8 != 0)
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return -1;
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*sizep = bits / 8;
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return 0;
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}
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static int
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pass_in_gpr_lp64 (const Dwarf_Op **locp, Dwarf_Word size)
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{
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static const Dwarf_Op loc[] =
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{
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{ .atom = DW_OP_reg10 }, { .atom = DW_OP_piece, .number = 8 },
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{ .atom = DW_OP_reg11 }, { .atom = DW_OP_piece, .number = 8 }
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};
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*locp = loc;
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return size <= 8 ? 1 : 4;
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}
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static int
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pass_by_ref (const Dwarf_Op **locp)
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{
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static const Dwarf_Op loc[] = { { .atom = DW_OP_breg10 } };
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*locp = loc;
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return 1;
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}
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static int
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pass_in_fpr_lp64f (const Dwarf_Op **locp, Dwarf_Word size)
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{
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static const Dwarf_Op loc[] =
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{
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{ .atom = DW_OP_regx, .number = 42 },
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{ .atom = DW_OP_piece, .number = 4 },
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{ .atom = DW_OP_regx, .number = 43 },
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{ .atom = DW_OP_piece, .number = 4 }
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};
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*locp = loc;
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return size <= 4 ? 1 : 4;
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}
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static int
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pass_in_fpr_lp64d (const Dwarf_Op **locp, Dwarf_Word size)
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{
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static const Dwarf_Op loc[] =
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{
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{ .atom = DW_OP_regx, .number = 42 },
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{ .atom = DW_OP_piece, .number = 8 },
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{ .atom = DW_OP_regx, .number = 43 },
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{ .atom = DW_OP_piece, .number = 8 }
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};
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*locp = loc;
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return size <= 8 ? 1 : 4;
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}
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static int
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flatten_aggregate_arg (Dwarf_Die *typedie __attribute__ ((unused)),
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Dwarf_Die *arg0 __attribute__ ((unused)),
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Dwarf_Die *arg1 __attribute__ ((unused)))
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{
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/* ??? */
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return 1;
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}
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static int
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pass_by_flattened_arg (const Dwarf_Op **locp __attribute__ ((unused)),
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Dwarf_Word size __attribute__ ((unused)),
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Dwarf_Die *arg0 __attribute__ ((unused)),
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Dwarf_Die *arg1 __attribute__ ((unused)))
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{
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/* ??? */
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return -2;
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}
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int
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riscv_return_value_location_lp64d (Dwarf_Die *functypedie,
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const Dwarf_Op **locp)
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{
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/* Start with the function's type, and get the DW_AT_type attribute,
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which is the type of the return value. */
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Dwarf_Die typedie;
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int tag = dwarf_peeled_die_type (functypedie, &typedie);
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if (tag <= 0)
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return tag;
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Dwarf_Word size = (Dwarf_Word)-1;
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/* If the argument type is a Composite Type that is larger than 16
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bytes, then the argument is copied to memory allocated by the
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caller and the argument is replaced by a pointer to the copy. */
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if (tag == DW_TAG_structure_type || tag == DW_TAG_union_type
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|| tag == DW_TAG_class_type || tag == DW_TAG_array_type)
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{
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Dwarf_Die arg0, arg1;
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if (dwarf_aggregate_size (&typedie, &size) < 0)
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return -1;
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/* A struct containing just one floating-point real is passed as though
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it were a standalone floating-point real. A struct containing two
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floating-point reals is passed in two floating-point registers, if
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neither is more than FLEN bits wide. A struct containing just one
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complex floating-point number is passed as though it were a struct
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containing two floating-point reals. A struct containing one
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floating-point real and one integer (or bitfield), in either order,
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is passed in a floating-point register and an integer register,
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provided the floating-point real is no more than FLEN bits wide and
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the integer is no more than XLEN bits wide. */
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if (tag == DW_TAG_structure_type
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&& flatten_aggregate_arg (&typedie, &arg0, &arg1))
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return pass_by_flattened_arg (locp, size, &arg0, &arg1);
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/* Aggregates larger than 2*XLEN bits are passed by reference. */
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else if (size > 16)
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return pass_by_ref (locp);
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/* Aggregates whose total size is no more than XLEN bits are passed in
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a register. Aggregates whose total size is no more than 2*XLEN bits
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are passed in a pair of registers. */
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else
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return pass_in_gpr_lp64 (locp, size);
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}
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if (tag == DW_TAG_base_type
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|| tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
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{
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if (dwarf_bytesize_aux (&typedie, &size) < 0)
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{
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if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
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size = 8;
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else
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return -1;
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}
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Dwarf_Attribute attr_mem;
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if (tag == DW_TAG_base_type)
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{
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Dwarf_Word encoding;
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if (dwarf_formudata (dwarf_attr_integrate (&typedie, DW_AT_encoding,
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&attr_mem),
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&encoding) != 0)
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return -1;
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switch (encoding)
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{
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case DW_ATE_boolean:
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case DW_ATE_signed:
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case DW_ATE_unsigned:
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case DW_ATE_unsigned_char:
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case DW_ATE_signed_char:
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/* Scalars that are at most XLEN bits wide are passed in a single
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argument register. Scalars that are 2*XLEN bits wide are
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passed in a pair of argument registers. Scalars wider than
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2*XLEN are passed by reference; there are none for LP64D. */
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return pass_in_gpr_lp64 (locp, size);
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case DW_ATE_float:
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/* A real floating-point argument is passed in a floating-point
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argument register if it is no more than FLEN bits wide,
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otherwise it is passed according to the integer calling
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convention. */
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switch (size)
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{
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case 4: /* single */
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case 8: /* double */
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return pass_in_fpr_lp64d (locp, size);
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case 16: /* quad */
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return pass_in_gpr_lp64 (locp, size);
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default:
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return -2;
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}
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case DW_ATE_complex_float:
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/* A complex floating-point number is passed as though it were a
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struct containing two floating-point reals. */
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switch (size)
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{
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case 8: /* float _Complex */
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return pass_in_fpr_lp64f (locp, size);
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case 16: /* double _Complex */
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return pass_in_fpr_lp64d (locp, size);
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case 32: /* long double _Complex */
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return pass_by_ref (locp);
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default:
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return -2;
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}
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}
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return -2;
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}
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else
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return pass_in_gpr_lp64 (locp, size);
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}
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*locp = NULL;
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return 0;
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}
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