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141 lines
3.7 KiB
141 lines
3.7 KiB
/* Function return value location for Linux/i386 ABI.
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Copyright (C) 2005-2010, 2014 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 <assert.h>
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#include <dwarf.h>
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#define BACKEND i386_
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#include "libebl_CPU.h"
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/* %eax, or pair %eax, %edx. */
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static const Dwarf_Op loc_intreg[] =
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{
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{ .atom = DW_OP_reg0 }, { .atom = DW_OP_piece, .number = 4 },
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{ .atom = DW_OP_reg2 }, { .atom = DW_OP_piece, .number = 4 },
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};
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#define nloc_intreg 1
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#define nloc_intregpair 4
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/* %st(0). */
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static const Dwarf_Op loc_fpreg[] =
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{
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{ .atom = DW_OP_reg11 }
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};
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#define nloc_fpreg 1
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/* The return value is a structure and is actually stored in stack space
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passed in a hidden argument by the caller. But, the compiler
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helpfully returns the address of that space in %eax. */
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static const Dwarf_Op loc_aggregate[] =
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{
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{ .atom = DW_OP_breg0, .number = 0 }
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};
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#define nloc_aggregate 1
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int
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i386_return_value_location (Dwarf_Die *functypedie, 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 die_mem, *typedie = &die_mem;
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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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switch (tag)
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{
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case -1:
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return -1;
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case DW_TAG_subrange_type:
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if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
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{
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Dwarf_Attribute attr_mem, *attr;
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attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
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typedie = dwarf_formref_die (attr, &die_mem);
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tag = DWARF_TAG_OR_RETURN (typedie);
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}
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FALLTHROUGH;
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case DW_TAG_base_type:
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case DW_TAG_enumeration_type:
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case DW_TAG_pointer_type:
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case DW_TAG_ptr_to_member_type:
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{
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Dwarf_Word size;
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Dwarf_Attribute attr_mem;
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if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
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&attr_mem), &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 = 4;
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else
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return -1;
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}
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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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if (encoding == DW_ATE_float)
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{
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if (size > 16)
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return -2;
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*locp = loc_fpreg;
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return nloc_fpreg;
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}
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}
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*locp = loc_intreg;
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if (size <= 4)
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return nloc_intreg;
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if (size <= 8)
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return nloc_intregpair;
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}
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FALLTHROUGH;
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case DW_TAG_structure_type:
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case DW_TAG_class_type:
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case DW_TAG_union_type:
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case DW_TAG_array_type:
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*locp = loc_aggregate;
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return nloc_aggregate;
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}
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/* XXX We don't have a good way to return specific errors from ebl calls.
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This value means we do not understand the type, but it is well-formed
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DWARF and might be valid. */
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return -2;
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}
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