| /* Function return value location for Linux/TILE-Gx ABI. |
| Copyright (C) 2012 Tilera Corporation |
| This file is part of elfutils. |
| |
| This file is free software; you can redistribute it and/or modify |
| it under the terms of either |
| |
| * the GNU Lesser General Public License as published by the Free |
| Software Foundation; either version 3 of the License, or (at |
| your option) any later version |
| |
| or |
| |
| * the GNU General Public License as published by the Free |
| Software Foundation; either version 2 of the License, or (at |
| your option) any later version |
| |
| or both in parallel, as here. |
| |
| elfutils is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received copies of the GNU General Public License and |
| the GNU Lesser General Public License along with this program. If |
| not, see <http://www.gnu.org/licenses/>. */ |
| |
| |
| #ifdef HAVE_CONFIG_H |
| # include <config.h> |
| #endif |
| |
| #include <assert.h> |
| #include <dwarf.h> |
| |
| #define BACKEND tilegx_ |
| #include "libebl_CPU.h" |
| |
| |
| /* r0. */ |
| static const Dwarf_Op loc_intreg[] = |
| { |
| { .atom = DW_OP_reg0 } |
| }; |
| #define nloc_intreg 1 |
| |
| /* The return value is a structure and is actually stored in stack space |
| passed in a hidden argument by the caller. But, the compiler |
| helpfully returns the address of that space in r0. */ |
| static const Dwarf_Op loc_aggregate[] = |
| { |
| { .atom = DW_OP_breg0, .number = 0 } |
| }; |
| #define nloc_aggregate 1 |
| |
| int |
| tilegx_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) |
| { |
| /* Start with the function's type, and get the DW_AT_type attribute, |
| which is the type of the return value. */ |
| |
| Dwarf_Attribute attr_mem; |
| Dwarf_Attribute *attr = dwarf_attr_integrate (functypedie, DW_AT_type, |
| &attr_mem); |
| if (attr == NULL) |
| /* The function has no return value, like a `void' function in C. */ |
| return 0; |
| |
| Dwarf_Die die_mem; |
| Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem); |
| int tag = DWARF_TAG_OR_RETURN (typedie); |
| |
| /* Follow typedefs and qualifiers to get to the actual type. */ |
| while (tag == DW_TAG_typedef |
| || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type |
| || tag == DW_TAG_restrict_type || tag == DW_TAG_mutable_type) |
| { |
| attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); |
| typedie = dwarf_formref_die (attr, &die_mem); |
| tag = DWARF_TAG_OR_RETURN (typedie); |
| } |
| |
| Dwarf_Word size; |
| switch (tag) |
| { |
| case -1: |
| return -1; |
| |
| case DW_TAG_subrange_type: |
| if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size)) |
| { |
| attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); |
| typedie = dwarf_formref_die (attr, &die_mem); |
| tag = DWARF_TAG_OR_RETURN (typedie); |
| } |
| /* Fall through. */ |
| |
| case DW_TAG_base_type: |
| case DW_TAG_enumeration_type: |
| case DW_TAG_pointer_type: |
| case DW_TAG_ptr_to_member_type: |
| if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, |
| &attr_mem), &size) != 0) |
| { |
| if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type) |
| size = 8; |
| else |
| return -1; |
| } |
| if (tag == DW_TAG_base_type) |
| { |
| Dwarf_Word encoding; |
| if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_encoding, |
| &attr_mem), |
| &encoding) != 0) |
| return -1; |
| } |
| |
| /* Small enough structs are passed directly in registers R0 ... R7. */ |
| if (size <= 8) |
| { |
| intreg: |
| *locp = loc_intreg; |
| return nloc_intreg; |
| } |
| |
| /* Else fall through. */ |
| case DW_TAG_structure_type: |
| case DW_TAG_class_type: |
| case DW_TAG_union_type: |
| aggregate: |
| *locp = loc_aggregate; |
| return nloc_aggregate; |
| |
| case DW_TAG_array_type: |
| case DW_TAG_string_type: |
| if (dwarf_aggregate_size (typedie, &size) == 0 && size <= 8) |
| { |
| if (tag == DW_TAG_array_type) |
| { |
| /* Check if it's a character array. */ |
| attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem); |
| typedie = dwarf_formref_die (attr, &die_mem); |
| tag = DWARF_TAG_OR_RETURN (typedie); |
| if (tag != DW_TAG_base_type) |
| goto aggregate; |
| if (dwarf_formudata (dwarf_attr_integrate (typedie, |
| DW_AT_byte_size, |
| &attr_mem), |
| &size) != 0) |
| return -1; |
| if (size != 1) |
| goto aggregate; |
| } |
| goto intreg; |
| } |
| goto aggregate; |
| } |
| |
| /* XXX We don't have a good way to return specific errors from ebl calls. |
| This value means we do not understand the type, but it is well-formed |
| DWARF and might be valid. */ |
| return -2; |
| } |