| /* Function return value location for S/390 ABI. |
| Copyright (C) 2006 Red Hat, Inc. |
| |
| This program is Open Source software; you can redistribute it and/or |
| modify it under the terms of the Open Software License version 1.0 as |
| published by the Open Source Initiative. |
| |
| You should have received a copy of the Open Software License along |
| with this program; if not, you may obtain a copy of the Open Software |
| License version 1.0 from http://www.opensource.org/licenses/osl.php or |
| by writing the Open Source Initiative c/o Lawrence Rosen, Esq., |
| 3001 King Ranch Road, Ukiah, CA 95482. */ |
| |
| #ifdef HAVE_CONFIG_H |
| # include <config.h> |
| #endif |
| |
| #include <assert.h> |
| #include <dwarf.h> |
| |
| #define BACKEND s390_ |
| #include "libebl_CPU.h" |
| |
| |
| /* %r2, or pair %r2, %r3. */ |
| static const Dwarf_Op loc_intreg[] = |
| { |
| { .atom = DW_OP_reg2 }, { .atom = DW_OP_piece, .number = 4 }, |
| { .atom = DW_OP_reg3 }, { .atom = DW_OP_piece, .number = 4 }, |
| }; |
| #define nloc_intreg 1 |
| #define nloc_intregpair 4 |
| |
| /* %f0. */ |
| static const Dwarf_Op loc_fpreg[] = |
| { |
| { .atom = DW_OP_reg16 }, |
| }; |
| #define nloc_fpreg 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 %r2. */ |
| static const Dwarf_Op loc_aggregate[] = |
| { |
| { .atom = DW_OP_breg2, .number = 0 } |
| }; |
| #define nloc_aggregate 1 |
| |
| |
| int |
| s390_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 (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 (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 (typedie, DW_AT_type, &attr_mem); |
| typedie = dwarf_formref_die (attr, &die_mem); |
| tag = dwarf_tag (typedie); |
| } |
| |
| Dwarf_Word size; |
| switch (tag) |
| { |
| case -1: |
| return -1; |
| |
| case DW_TAG_subrange_type: |
| if (! dwarf_hasattr (typedie, DW_AT_byte_size)) |
| { |
| attr = dwarf_attr (typedie, DW_AT_type, &attr_mem); |
| typedie = dwarf_formref_die (attr, &die_mem); |
| tag = dwarf_tag (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: |
| { |
| Dwarf_Die cudie; |
| uint8_t asize; |
| if (dwarf_diecu (typedie, &cudie, &asize, NULL) == NULL) |
| return -1; |
| |
| if (dwarf_formudata (dwarf_attr (typedie, DW_AT_byte_size, |
| &attr_mem), &size) != 0) |
| { |
| if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type) |
| size = asize; |
| else |
| return -1; |
| } |
| if (tag == DW_TAG_base_type) |
| { |
| Dwarf_Word encoding; |
| if (dwarf_formudata (dwarf_attr (typedie, DW_AT_encoding, |
| &attr_mem), &encoding) != 0) |
| return -1; |
| if (encoding == DW_ATE_float && size <= 8) |
| { |
| *locp = loc_fpreg; |
| return nloc_fpreg; |
| } |
| } |
| if (size <= 8) |
| { |
| *locp = loc_intreg; |
| return size <= asize ? nloc_intreg : nloc_intregpair; |
| } |
| } |
| /* Fall through. */ |
| |
| case DW_TAG_structure_type: |
| case DW_TAG_class_type: |
| case DW_TAG_union_type: |
| case DW_TAG_array_type: |
| *locp = loc_aggregate; |
| return nloc_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; |
| } |