Patrick Williams | d8c66bc | 2016-06-20 12:57:21 -0500 | [diff] [blame] | 1 | From fdaab18a65ed2529656baa64cb6169f34d7e507b Mon Sep 17 00:00:00 2001 |
| 2 | From: James Cowgill <james410@cowgill.org.uk> |
| 3 | Date: Mon, 5 Jan 2015 15:17:01 +0000 |
| 4 | Subject: [PATCH 2/3] Add support for mips64 abis in mips_retval.c |
| 5 | |
| 6 | Signed-off-by: James Cowgill <james410@cowgill.org.uk> |
| 7 | --- |
| 8 | backends/mips_retval.c | 104 ++++++++++++++++++++++++++++++++++++++++++++----- |
| 9 | 1 file changed, 94 insertions(+), 10 deletions(-) |
| 10 | |
| 11 | diff --git a/backends/mips_retval.c b/backends/mips_retval.c |
| 12 | index 33f12a7..d5c6ef0 100644 |
| 13 | --- a/backends/mips_retval.c |
| 14 | +++ b/backends/mips_retval.c |
| 15 | @@ -91,6 +91,8 @@ enum mips_abi find_mips_abi(Elf *elf) |
| 16 | default: |
| 17 | if ((elf_flags & EF_MIPS_ABI2)) |
| 18 | return MIPS_ABI_N32; |
| 19 | + else if ((ehdr->e_ident[EI_CLASS] == ELFCLASS64)) |
| 20 | + return MIPS_ABI_N64; |
| 21 | } |
| 22 | |
| 23 | /* GCC creates a pseudo-section whose name describes the ABI. */ |
| 24 | @@ -195,6 +197,57 @@ static const Dwarf_Op loc_aggregate[] = |
| 25 | }; |
| 26 | #define nloc_aggregate 1 |
| 27 | |
| 28 | +/* Test if a struct member is a float */ |
| 29 | +static int is_float_child(Dwarf_Die *childdie) |
| 30 | +{ |
| 31 | + /* Test if this is actually a struct member */ |
| 32 | + if (dwarf_tag(childdie) != DW_TAG_member) |
| 33 | + return 0; |
| 34 | + |
| 35 | + /* Get type of member */ |
| 36 | + Dwarf_Attribute attr_mem; |
| 37 | + Dwarf_Die child_type_mem; |
| 38 | + Dwarf_Die *child_typedie = |
| 39 | + dwarf_formref_die(dwarf_attr_integrate(childdie, |
| 40 | + DW_AT_type, |
| 41 | + &attr_mem), &child_type_mem); |
| 42 | + |
| 43 | + if (dwarf_tag(child_typedie) != DW_TAG_base_type) |
| 44 | + return 0; |
| 45 | + |
| 46 | + /* Get base subtype */ |
| 47 | + Dwarf_Word encoding; |
| 48 | + if (dwarf_formudata (dwarf_attr_integrate (child_typedie, |
| 49 | + DW_AT_encoding, |
| 50 | + &attr_mem), &encoding) != 0) |
| 51 | + return 0; |
| 52 | + |
| 53 | + return encoding == DW_ATE_float; |
| 54 | +} |
| 55 | + |
| 56 | +/* Returns the number of fpregs which can be returned in the given struct */ |
| 57 | +static int get_struct_fpregs(Dwarf_Die *structtypedie) |
| 58 | +{ |
| 59 | + Dwarf_Die child_mem; |
| 60 | + int fpregs = 0; |
| 61 | + |
| 62 | + /* Get first structure member */ |
| 63 | + if (dwarf_child(structtypedie, &child_mem) != 0) |
| 64 | + return 0; |
| 65 | + |
| 66 | + do |
| 67 | + { |
| 68 | + /* Ensure this register is a float */ |
| 69 | + if (!is_float_child(&child_mem)) |
| 70 | + return 0; |
| 71 | + |
| 72 | + fpregs++; |
| 73 | + } |
| 74 | + while (dwarf_siblingof (&child_mem, &child_mem) == 0); |
| 75 | + |
| 76 | + return fpregs; |
| 77 | +} |
| 78 | + |
| 79 | int |
| 80 | mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) |
| 81 | { |
| 82 | @@ -240,6 +293,7 @@ mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) |
| 83 | tag = dwarf_tag (typedie); |
| 84 | } |
| 85 | |
| 86 | + Dwarf_Word size; |
| 87 | switch (tag) |
| 88 | { |
| 89 | case -1: |
| 90 | @@ -258,8 +312,6 @@ mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) |
| 91 | case DW_TAG_enumeration_type: |
| 92 | case DW_TAG_pointer_type: |
| 93 | case DW_TAG_ptr_to_member_type: |
| 94 | - { |
| 95 | - Dwarf_Word size; |
| 96 | if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, |
| 97 | &attr_mem), &size) != 0) |
| 98 | { |
| 99 | @@ -289,7 +341,7 @@ mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) |
| 100 | if (size <= 4*regsize && abi == MIPS_ABI_O32) |
| 101 | return nloc_fpregquad; |
| 102 | |
| 103 | - goto aggregate; |
| 104 | + goto large; |
| 105 | } |
| 106 | } |
| 107 | *locp = ABI_LOC(loc_intreg, regsize); |
| 108 | @@ -298,18 +350,50 @@ mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) |
| 109 | if (size <= 2*regsize) |
| 110 | return nloc_intregpair; |
| 111 | |
| 112 | - /* Else fall through. Shouldn't happen though (at least with gcc) */ |
| 113 | - } |
| 114 | + /* Else pass in memory. Shouldn't happen though (at least with gcc) */ |
| 115 | + goto large; |
| 116 | |
| 117 | case DW_TAG_structure_type: |
| 118 | case DW_TAG_class_type: |
| 119 | case DW_TAG_union_type: |
| 120 | - case DW_TAG_array_type: |
| 121 | - aggregate: |
| 122 | - /* XXX TODO: Can't handle structure return with other ABI's yet :-/ */ |
| 123 | - if ((abi != MIPS_ABI_O32) && (abi != MIPS_ABI_O64)) |
| 124 | - return -2; |
| 125 | + /* Handle special cases for structures <= 128 bytes in newer ABIs */ |
| 126 | + if (abi == MIPS_ABI_EABI32 || abi == MIPS_ABI_EABI64 || |
| 127 | + abi == MIPS_ABI_N32 || abi == MIPS_ABI_N64) |
| 128 | + { |
| 129 | + if (dwarf_aggregate_size (typedie, &size) == 0 && size <= 16) |
| 130 | + { |
| 131 | + /* |
| 132 | + * Special case in N64 / N32 - |
| 133 | + * structures containing only floats are returned in fp regs. |
| 134 | + * Everything else is returned in integer regs. |
| 135 | + */ |
| 136 | + if (tag != DW_TAG_union_type && |
| 137 | + (abi == MIPS_ABI_N32 || abi == MIPS_ABI_N64)) |
| 138 | + { |
| 139 | + int num_fpregs = get_struct_fpregs(typedie); |
| 140 | + if (num_fpregs == 1 || num_fpregs == 2) |
| 141 | + { |
| 142 | + *locp = loc_fpreg; |
| 143 | + if (num_fpregs == 1) |
| 144 | + return nloc_fpreg; |
| 145 | + else |
| 146 | + return nloc_fpregpair; |
| 147 | + } |
| 148 | + } |
| 149 | + |
| 150 | + *locp = loc_intreg; |
| 151 | + if (size <= 8) |
| 152 | + return nloc_intreg; |
| 153 | + else |
| 154 | + return nloc_intregpair; |
| 155 | + } |
| 156 | + } |
| 157 | + |
| 158 | + /* Fallthrough to handle large types */ |
| 159 | |
| 160 | + case DW_TAG_array_type: |
| 161 | + large: |
| 162 | + /* Return large structures in memory */ |
| 163 | *locp = loc_aggregate; |
| 164 | return nloc_aggregate; |
| 165 | } |
| 166 | -- |
| 167 | 2.1.4 |
| 168 | |