diff options
Diffstat (limited to 'backends/m68k_retval.c')
| -rw-r--r-- | backends/m68k_retval.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/backends/m68k_retval.c b/backends/m68k_retval.c new file mode 100644 index 00000000..2dd285a0 --- /dev/null +++ b/backends/m68k_retval.c @@ -0,0 +1,153 @@ +/* Function return value location for Linux/m68k ABI. + 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 m68k_ +#include "libebl_CPU.h" + + +/* %d0, or pair %d0, %d1. */ +static const Dwarf_Op loc_intreg[] = + { + { .atom = DW_OP_reg0 }, { .atom = DW_OP_piece, .number = 4 }, + { .atom = DW_OP_reg1 }, { .atom = DW_OP_piece, .number = 4 }, + }; +#define nloc_intreg 1 +#define nloc_intregpair 4 + +/* %a0. */ +static const Dwarf_Op loc_ptrreg[] = + { + { .atom = DW_OP_reg8 } + }; +#define nloc_ptrreg 1 + +/* %fp0. */ +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 %a0. */ +static const Dwarf_Op loc_aggregate[] = + { + { .atom = DW_OP_reg8 } + }; +#define nloc_aggregate 1 + +int +m68k_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_Die die_mem, *typedie = &die_mem; + int tag = dwarf_peeled_die_type (functypedie, typedie); + if (tag <= 0) + return tag; + + switch (tag) + { + case -1: + return -1; + + case DW_TAG_subrange_type: + if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size)) + { + Dwarf_Attribute attr_mem, *attr; + 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: + { + Dwarf_Word size; + Dwarf_Attribute attr_mem; + 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 = 4; + 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; + if (encoding == DW_ATE_float) + { + if (size > 12) + return -2; + *locp = loc_fpreg; + return nloc_fpreg; + } + } + if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type) + { + *locp = loc_ptrreg; + return nloc_ptrreg; + } + *locp = loc_intreg; + if (size <= 4) + return nloc_intreg; + if (size <= 8) + return nloc_intregpair; + + /* Else 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; +} |