125b3c049e70834cf33790a28643ab058b507b35cBen Cheng/* Function return value location for Linux/i386 ABI. 203333823c75a1c1887e923828113a1b0fd12020cElliott Hughes Copyright (C) 2005-2010, 2014 Red Hat, Inc. 303333823c75a1c1887e923828113a1b0fd12020cElliott Hughes This file is part of elfutils. 425b3c049e70834cf33790a28643ab058b507b35cBen Cheng 503333823c75a1c1887e923828113a1b0fd12020cElliott Hughes This file is free software; you can redistribute it and/or modify 603333823c75a1c1887e923828113a1b0fd12020cElliott Hughes it under the terms of either 725b3c049e70834cf33790a28643ab058b507b35cBen Cheng 803333823c75a1c1887e923828113a1b0fd12020cElliott Hughes * the GNU Lesser General Public License as published by the Free 903333823c75a1c1887e923828113a1b0fd12020cElliott Hughes Software Foundation; either version 3 of the License, or (at 1003333823c75a1c1887e923828113a1b0fd12020cElliott Hughes your option) any later version 1103333823c75a1c1887e923828113a1b0fd12020cElliott Hughes 1203333823c75a1c1887e923828113a1b0fd12020cElliott Hughes or 1303333823c75a1c1887e923828113a1b0fd12020cElliott Hughes 1403333823c75a1c1887e923828113a1b0fd12020cElliott Hughes * the GNU General Public License as published by the Free 1503333823c75a1c1887e923828113a1b0fd12020cElliott Hughes Software Foundation; either version 2 of the License, or (at 1603333823c75a1c1887e923828113a1b0fd12020cElliott Hughes your option) any later version 1703333823c75a1c1887e923828113a1b0fd12020cElliott Hughes 1803333823c75a1c1887e923828113a1b0fd12020cElliott Hughes or both in parallel, as here. 1903333823c75a1c1887e923828113a1b0fd12020cElliott Hughes 2003333823c75a1c1887e923828113a1b0fd12020cElliott Hughes elfutils is distributed in the hope that it will be useful, but 2125b3c049e70834cf33790a28643ab058b507b35cBen Cheng WITHOUT ANY WARRANTY; without even the implied warranty of 2225b3c049e70834cf33790a28643ab058b507b35cBen Cheng MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 2325b3c049e70834cf33790a28643ab058b507b35cBen Cheng General Public License for more details. 2425b3c049e70834cf33790a28643ab058b507b35cBen Cheng 2503333823c75a1c1887e923828113a1b0fd12020cElliott Hughes You should have received copies of the GNU General Public License and 2603333823c75a1c1887e923828113a1b0fd12020cElliott Hughes the GNU Lesser General Public License along with this program. If 2703333823c75a1c1887e923828113a1b0fd12020cElliott Hughes not, see <http://www.gnu.org/licenses/>. */ 2825b3c049e70834cf33790a28643ab058b507b35cBen Cheng 2925b3c049e70834cf33790a28643ab058b507b35cBen Cheng#ifdef HAVE_CONFIG_H 3025b3c049e70834cf33790a28643ab058b507b35cBen Cheng# include <config.h> 3125b3c049e70834cf33790a28643ab058b507b35cBen Cheng#endif 3225b3c049e70834cf33790a28643ab058b507b35cBen Cheng 3325b3c049e70834cf33790a28643ab058b507b35cBen Cheng#include <assert.h> 3425b3c049e70834cf33790a28643ab058b507b35cBen Cheng#include <dwarf.h> 3525b3c049e70834cf33790a28643ab058b507b35cBen Cheng 3625b3c049e70834cf33790a28643ab058b507b35cBen Cheng#define BACKEND i386_ 3725b3c049e70834cf33790a28643ab058b507b35cBen Cheng#include "libebl_CPU.h" 3825b3c049e70834cf33790a28643ab058b507b35cBen Cheng 3925b3c049e70834cf33790a28643ab058b507b35cBen Cheng 4025b3c049e70834cf33790a28643ab058b507b35cBen Cheng/* %eax, or pair %eax, %edx. */ 4125b3c049e70834cf33790a28643ab058b507b35cBen Chengstatic const Dwarf_Op loc_intreg[] = 4225b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 4325b3c049e70834cf33790a28643ab058b507b35cBen Cheng { .atom = DW_OP_reg0 }, { .atom = DW_OP_piece, .number = 4 }, 4425b3c049e70834cf33790a28643ab058b507b35cBen Cheng { .atom = DW_OP_reg2 }, { .atom = DW_OP_piece, .number = 4 }, 4525b3c049e70834cf33790a28643ab058b507b35cBen Cheng }; 4625b3c049e70834cf33790a28643ab058b507b35cBen Cheng#define nloc_intreg 1 4725b3c049e70834cf33790a28643ab058b507b35cBen Cheng#define nloc_intregpair 4 4825b3c049e70834cf33790a28643ab058b507b35cBen Cheng 4925b3c049e70834cf33790a28643ab058b507b35cBen Cheng/* %st(0). */ 5025b3c049e70834cf33790a28643ab058b507b35cBen Chengstatic const Dwarf_Op loc_fpreg[] = 5125b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 5225b3c049e70834cf33790a28643ab058b507b35cBen Cheng { .atom = DW_OP_reg11 } 5325b3c049e70834cf33790a28643ab058b507b35cBen Cheng }; 5425b3c049e70834cf33790a28643ab058b507b35cBen Cheng#define nloc_fpreg 1 5525b3c049e70834cf33790a28643ab058b507b35cBen Cheng 5625b3c049e70834cf33790a28643ab058b507b35cBen Cheng/* The return value is a structure and is actually stored in stack space 5725b3c049e70834cf33790a28643ab058b507b35cBen Cheng passed in a hidden argument by the caller. But, the compiler 5825b3c049e70834cf33790a28643ab058b507b35cBen Cheng helpfully returns the address of that space in %eax. */ 5925b3c049e70834cf33790a28643ab058b507b35cBen Chengstatic const Dwarf_Op loc_aggregate[] = 6025b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 6125b3c049e70834cf33790a28643ab058b507b35cBen Cheng { .atom = DW_OP_breg0, .number = 0 } 6225b3c049e70834cf33790a28643ab058b507b35cBen Cheng }; 6325b3c049e70834cf33790a28643ab058b507b35cBen Cheng#define nloc_aggregate 1 6425b3c049e70834cf33790a28643ab058b507b35cBen Cheng 6525b3c049e70834cf33790a28643ab058b507b35cBen Chengint 6625b3c049e70834cf33790a28643ab058b507b35cBen Chengi386_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) 6725b3c049e70834cf33790a28643ab058b507b35cBen Cheng{ 6825b3c049e70834cf33790a28643ab058b507b35cBen Cheng /* Start with the function's type, and get the DW_AT_type attribute, 6925b3c049e70834cf33790a28643ab058b507b35cBen Cheng which is the type of the return value. */ 7003333823c75a1c1887e923828113a1b0fd12020cElliott Hughes Dwarf_Die die_mem, *typedie = &die_mem; 7103333823c75a1c1887e923828113a1b0fd12020cElliott Hughes int tag = dwarf_peeled_die_type (functypedie, typedie); 7203333823c75a1c1887e923828113a1b0fd12020cElliott Hughes if (tag <= 0) 7303333823c75a1c1887e923828113a1b0fd12020cElliott Hughes return tag; 7425b3c049e70834cf33790a28643ab058b507b35cBen Cheng 7525b3c049e70834cf33790a28643ab058b507b35cBen Cheng switch (tag) 7625b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 7725b3c049e70834cf33790a28643ab058b507b35cBen Cheng case -1: 7825b3c049e70834cf33790a28643ab058b507b35cBen Cheng return -1; 7925b3c049e70834cf33790a28643ab058b507b35cBen Cheng 8025b3c049e70834cf33790a28643ab058b507b35cBen Cheng case DW_TAG_subrange_type: 8125b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size)) 8225b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 8303333823c75a1c1887e923828113a1b0fd12020cElliott Hughes Dwarf_Attribute attr_mem, *attr; 8425b3c049e70834cf33790a28643ab058b507b35cBen Cheng attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); 8525b3c049e70834cf33790a28643ab058b507b35cBen Cheng typedie = dwarf_formref_die (attr, &die_mem); 8603333823c75a1c1887e923828113a1b0fd12020cElliott Hughes tag = DWARF_TAG_OR_RETURN (typedie); 8725b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 8825b3c049e70834cf33790a28643ab058b507b35cBen Cheng /* Fall through. */ 8925b3c049e70834cf33790a28643ab058b507b35cBen Cheng 9025b3c049e70834cf33790a28643ab058b507b35cBen Cheng case DW_TAG_base_type: 9125b3c049e70834cf33790a28643ab058b507b35cBen Cheng case DW_TAG_enumeration_type: 9225b3c049e70834cf33790a28643ab058b507b35cBen Cheng case DW_TAG_pointer_type: 9325b3c049e70834cf33790a28643ab058b507b35cBen Cheng case DW_TAG_ptr_to_member_type: 9425b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 9525b3c049e70834cf33790a28643ab058b507b35cBen Cheng Dwarf_Word size; 9603333823c75a1c1887e923828113a1b0fd12020cElliott Hughes Dwarf_Attribute attr_mem; 9725b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, 9825b3c049e70834cf33790a28643ab058b507b35cBen Cheng &attr_mem), &size) != 0) 9925b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 10025b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type) 10125b3c049e70834cf33790a28643ab058b507b35cBen Cheng size = 4; 10225b3c049e70834cf33790a28643ab058b507b35cBen Cheng else 10325b3c049e70834cf33790a28643ab058b507b35cBen Cheng return -1; 10425b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 10525b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (tag == DW_TAG_base_type) 10625b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 10725b3c049e70834cf33790a28643ab058b507b35cBen Cheng Dwarf_Word encoding; 10825b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding, 10925b3c049e70834cf33790a28643ab058b507b35cBen Cheng &attr_mem), 11025b3c049e70834cf33790a28643ab058b507b35cBen Cheng &encoding) != 0) 11125b3c049e70834cf33790a28643ab058b507b35cBen Cheng return -1; 11225b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (encoding == DW_ATE_float) 11325b3c049e70834cf33790a28643ab058b507b35cBen Cheng { 11425b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (size > 16) 11525b3c049e70834cf33790a28643ab058b507b35cBen Cheng return -2; 11625b3c049e70834cf33790a28643ab058b507b35cBen Cheng *locp = loc_fpreg; 11725b3c049e70834cf33790a28643ab058b507b35cBen Cheng return nloc_fpreg; 11825b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 11925b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 12025b3c049e70834cf33790a28643ab058b507b35cBen Cheng *locp = loc_intreg; 12125b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (size <= 4) 12225b3c049e70834cf33790a28643ab058b507b35cBen Cheng return nloc_intreg; 12325b3c049e70834cf33790a28643ab058b507b35cBen Cheng if (size <= 8) 12425b3c049e70834cf33790a28643ab058b507b35cBen Cheng return nloc_intregpair; 12525b3c049e70834cf33790a28643ab058b507b35cBen Cheng 12625b3c049e70834cf33790a28643ab058b507b35cBen Cheng /* Else fall through. */ 12725b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 12825b3c049e70834cf33790a28643ab058b507b35cBen Cheng 12925b3c049e70834cf33790a28643ab058b507b35cBen Cheng case DW_TAG_structure_type: 13025b3c049e70834cf33790a28643ab058b507b35cBen Cheng case DW_TAG_class_type: 13125b3c049e70834cf33790a28643ab058b507b35cBen Cheng case DW_TAG_union_type: 13225b3c049e70834cf33790a28643ab058b507b35cBen Cheng case DW_TAG_array_type: 13325b3c049e70834cf33790a28643ab058b507b35cBen Cheng *locp = loc_aggregate; 13425b3c049e70834cf33790a28643ab058b507b35cBen Cheng return nloc_aggregate; 13525b3c049e70834cf33790a28643ab058b507b35cBen Cheng } 13625b3c049e70834cf33790a28643ab058b507b35cBen Cheng 13725b3c049e70834cf33790a28643ab058b507b35cBen Cheng /* XXX We don't have a good way to return specific errors from ebl calls. 13825b3c049e70834cf33790a28643ab058b507b35cBen Cheng This value means we do not understand the type, but it is well-formed 13925b3c049e70834cf33790a28643ab058b507b35cBen Cheng DWARF and might be valid. */ 14025b3c049e70834cf33790a28643ab058b507b35cBen Cheng return -2; 14125b3c049e70834cf33790a28643ab058b507b35cBen Cheng} 142