1 /* Function return value location for SPARC. 2 Copyright (C) 2006, 2007 Red Hat, Inc. 3 4 This program is Open Source software; you can redistribute it and/or 5 modify it under the terms of the Open Software License version 1.0 as 6 published by the Open Source Initiative. 7 8 You should have received a copy of the Open Software License along 9 with this program; if not, you may obtain a copy of the Open Software 10 License version 1.0 from http://www.opensource.org/licenses/osl.php or 11 by writing the Open Source Initiative c/o Lawrence Rosen, Esq., 12 3001 King Ranch Road, Ukiah, CA 95482. */ 13 14 #ifdef HAVE_CONFIG_H 15 # include <config.h> 16 #endif 17 18 #include <assert.h> 19 #include <dwarf.h> 20 21 #define BACKEND sparc_ 22 #include "libebl_CPU.h" 23 24 25 /* %o0, or pair %o0, %o1. */ 26 static const Dwarf_Op loc_intreg[] = 27 { 28 { .atom = DW_OP_reg8 }, { .atom = DW_OP_piece, .number = 4 }, 29 { .atom = DW_OP_reg9 }, { .atom = DW_OP_piece, .number = 4 }, 30 }; 31 #define nloc_intreg 1 32 #define nloc_intregpair 4 33 34 /* %f0 or pair %f0, %f1, or quad %f0..%f3. */ 35 static const Dwarf_Op loc_fpreg[] = 36 { 37 { .atom = DW_OP_regx, .number = 32 }, { .atom = DW_OP_piece, .number = 4 }, 38 { .atom = DW_OP_regx, .number = 33 }, { .atom = DW_OP_piece, .number = 4 }, 39 { .atom = DW_OP_regx, .number = 34 }, { .atom = DW_OP_piece, .number = 4 }, 40 { .atom = DW_OP_regx, .number = 35 }, { .atom = DW_OP_piece, .number = 4 }, 41 }; 42 #define nloc_fpreg 1 43 #define nloc_fpregpair 4 44 #define nloc_fpregquad 8 45 46 /* The return value is a structure and is actually stored in stack space 47 passed in a hidden argument by the caller. But, the compiler 48 helpfully returns the address of that space in %o0. */ 49 static const Dwarf_Op loc_aggregate[] = 50 { 51 { .atom = DW_OP_breg8, .number = 0 } 52 }; 53 #define nloc_aggregate 1 54 55 int 56 sparc_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) 57 { 58 /* Start with the function's type, and get the DW_AT_type attribute, 59 which is the type of the return value. */ 60 61 Dwarf_Attribute attr_mem; 62 Dwarf_Attribute *attr = dwarf_attr_integrate (functypedie, DW_AT_type, 63 &attr_mem); 64 if (attr == NULL) 65 /* The function has no return value, like a `void' function in C. */ 66 return 0; 67 68 Dwarf_Die die_mem; 69 Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem); 70 int tag = dwarf_tag (typedie); 71 72 /* Follow typedefs and qualifiers to get to the actual type. */ 73 while (tag == DW_TAG_typedef 74 || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type 75 || tag == DW_TAG_restrict_type || tag == DW_TAG_mutable_type) 76 { 77 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); 78 typedie = dwarf_formref_die (attr, &die_mem); 79 tag = dwarf_tag (typedie); 80 } 81 82 Dwarf_Word size; 83 switch (tag) 84 { 85 case -1: 86 return -1; 87 88 case DW_TAG_subrange_type: 89 if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size)) 90 { 91 attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); 92 typedie = dwarf_formref_die (attr, &die_mem); 93 tag = dwarf_tag (typedie); 94 } 95 /* Fall through. */ 96 97 case DW_TAG_base_type: 98 case DW_TAG_enumeration_type: 99 case DW_TAG_pointer_type: 100 case DW_TAG_ptr_to_member_type: 101 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, 102 &attr_mem), &size) != 0) 103 { 104 uint8_t asize; 105 Dwarf_Die cudie; 106 if ((tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type) 107 && dwarf_diecu (typedie, &cudie, &asize, NULL) != NULL) 108 size = asize; 109 else 110 return -1; 111 } 112 if (tag == DW_TAG_base_type) 113 { 114 Dwarf_Word encoding; 115 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding, 116 &attr_mem), 117 &encoding) != 0) 118 return -1; 119 if (encoding == DW_ATE_float) 120 { 121 *locp = loc_fpreg; 122 if (size <= 4) 123 return nloc_fpreg; 124 if (size <= 8) 125 return nloc_fpregpair; 126 if (size <= 16) 127 return nloc_fpregquad; 128 } 129 } 130 if (size <= 8) 131 { 132 intreg: 133 *locp = loc_intreg; 134 return size <= 4 ? nloc_intreg : nloc_intregpair; 135 } 136 137 aggregate: 138 *locp = loc_aggregate; 139 return nloc_aggregate; 140 141 case DW_TAG_structure_type: 142 case DW_TAG_class_type: 143 case DW_TAG_union_type: 144 case DW_TAG_array_type: 145 if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, 146 &attr_mem), &size) == 0 147 && size > 0 && size <= 8) 148 goto intreg; 149 goto aggregate; 150 } 151 152 /* XXX We don't have a good way to return specific errors from ebl calls. 153 This value means we do not understand the type, but it is well-formed 154 DWARF and might be valid. */ 155 return -2; 156 } 157