1 /* Function return value location for S/390 ABI. 2 Copyright (C) 2006, 2007, 2014 Red Hat, Inc. 3 This file is part of elfutils. 4 5 This file is free software; you can redistribute it and/or modify 6 it under the terms of either 7 8 * the GNU Lesser General Public License as published by the Free 9 Software Foundation; either version 3 of the License, or (at 10 your option) any later version 11 12 or 13 14 * the GNU General Public License as published by the Free 15 Software Foundation; either version 2 of the License, or (at 16 your option) any later version 17 18 or both in parallel, as here. 19 20 elfutils is distributed in the hope that it will be useful, but 21 WITHOUT ANY WARRANTY; without even the implied warranty of 22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 23 General Public License for more details. 24 25 You should have received copies of the GNU General Public License and 26 the GNU Lesser General Public License along with this program. If 27 not, see <http://www.gnu.org/licenses/>. */ 28 29 #ifdef HAVE_CONFIG_H 30 # include <config.h> 31 #endif 32 33 #include <assert.h> 34 #include <dwarf.h> 35 36 #define BACKEND s390_ 37 #include "libebl_CPU.h" 38 39 40 /* %r2, or pair %r2, %r3. */ 41 static const Dwarf_Op loc_intreg[] = 42 { 43 { .atom = DW_OP_reg2 }, { .atom = DW_OP_piece, .number = 4 }, 44 { .atom = DW_OP_reg3 }, { .atom = DW_OP_piece, .number = 4 }, 45 }; 46 #define nloc_intreg 1 47 #define nloc_intregpair 4 48 49 /* %f0. */ 50 static const Dwarf_Op loc_fpreg[] = 51 { 52 { .atom = DW_OP_reg16 }, 53 }; 54 #define nloc_fpreg 1 55 56 /* The return value is a structure and is actually stored in stack space 57 passed in a hidden argument by the caller. But, the compiler 58 helpfully returns the address of that space in %r2. */ 59 static const Dwarf_Op loc_aggregate[] = 60 { 61 { .atom = DW_OP_breg2, .number = 0 } 62 }; 63 #define nloc_aggregate 1 64 65 66 int 67 s390_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) 68 { 69 /* Start with the function's type, and get the DW_AT_type attribute, 70 which is the type of the return value. */ 71 Dwarf_Die die_mem, *typedie = &die_mem; 72 int tag = dwarf_peeled_die_type (functypedie, typedie); 73 if (tag <= 0) 74 return tag; 75 76 Dwarf_Word size; 77 switch (tag) 78 { 79 case -1: 80 return -1; 81 82 case DW_TAG_subrange_type: 83 if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size)) 84 { 85 Dwarf_Attribute attr_mem, *attr; 86 attr = dwarf_attr (typedie, DW_AT_type, &attr_mem); 87 typedie = dwarf_formref_die (attr, &die_mem); 88 tag = DWARF_TAG_OR_RETURN (typedie); 89 } 90 /* Fall through. */ 91 92 case DW_TAG_base_type: 93 case DW_TAG_enumeration_type: 94 case DW_TAG_pointer_type: 95 case DW_TAG_ptr_to_member_type: 96 { 97 Dwarf_Die cudie; 98 uint8_t asize; 99 if (dwarf_diecu (typedie, &cudie, &asize, NULL) == NULL) 100 return -1; 101 102 Dwarf_Attribute attr_mem; 103 if (dwarf_formudata (dwarf_attr (typedie, DW_AT_byte_size, 104 &attr_mem), &size) != 0) 105 { 106 if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type) 107 size = asize; 108 else 109 return -1; 110 } 111 if (tag == DW_TAG_base_type) 112 { 113 Dwarf_Word encoding; 114 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding, 115 &attr_mem), 116 &encoding) != 0) 117 return -1; 118 if (encoding == DW_ATE_float && size <= 8) 119 { 120 *locp = loc_fpreg; 121 return nloc_fpreg; 122 } 123 } 124 if (size <= 8) 125 { 126 *locp = loc_intreg; 127 return size <= asize ? nloc_intreg : nloc_intregpair; 128 } 129 } 130 /* Fall through. */ 131 132 case DW_TAG_structure_type: 133 case DW_TAG_class_type: 134 case DW_TAG_union_type: 135 case DW_TAG_array_type: 136 *locp = loc_aggregate; 137 return nloc_aggregate; 138 } 139 140 /* XXX We don't have a good way to return specific errors from ebl calls. 141 This value means we do not understand the type, but it is well-formed 142 DWARF and might be valid. */ 143 return -2; 144 } 145
