From fdaab18a65ed2529656baa64cb6169f34d7e507b Mon Sep 17 00:00:00 2001 From: James Cowgill Date: Mon, 5 Jan 2015 15:17:01 +0000 Subject: [PATCH 2/3] Add support for mips64 abis in mips_retval.c Signed-off-by: James Cowgill Upstream-Status: Pending [from debian] Signed-off-by: Hongxu Jia --- backends/mips_retval.c | 104 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 94 insertions(+), 10 deletions(-) diff --git a/backends/mips_retval.c b/backends/mips_retval.c index 33f12a7..d5c6ef0 100644 --- a/backends/mips_retval.c +++ b/backends/mips_retval.c @@ -91,6 +91,8 @@ enum mips_abi find_mips_abi(Elf *elf) default: if ((elf_flags & EF_MIPS_ABI2)) return MIPS_ABI_N32; + else if ((ehdr->e_ident[EI_CLASS] == ELFCLASS64)) + return MIPS_ABI_N64; } /* GCC creates a pseudo-section whose name describes the ABI. */ @@ -195,6 +197,57 @@ static const Dwarf_Op loc_aggregate[] = }; #define nloc_aggregate 1 +/* Test if a struct member is a float */ +static int is_float_child(Dwarf_Die *childdie) +{ + /* Test if this is actually a struct member */ + if (dwarf_tag(childdie) != DW_TAG_member) + return 0; + + /* Get type of member */ + Dwarf_Attribute attr_mem; + Dwarf_Die child_type_mem; + Dwarf_Die *child_typedie = + dwarf_formref_die(dwarf_attr_integrate(childdie, + DW_AT_type, + &attr_mem), &child_type_mem); + + if (dwarf_tag(child_typedie) != DW_TAG_base_type) + return 0; + + /* Get base subtype */ + Dwarf_Word encoding; + if (dwarf_formudata (dwarf_attr_integrate (child_typedie, + DW_AT_encoding, + &attr_mem), &encoding) != 0) + return 0; + + return encoding == DW_ATE_float; +} + +/* Returns the number of fpregs which can be returned in the given struct */ +static int get_struct_fpregs(Dwarf_Die *structtypedie) +{ + Dwarf_Die child_mem; + int fpregs = 0; + + /* Get first structure member */ + if (dwarf_child(structtypedie, &child_mem) != 0) + return 0; + + do + { + /* Ensure this register is a float */ + if (!is_float_child(&child_mem)) + return 0; + + fpregs++; + } + while (dwarf_siblingof (&child_mem, &child_mem) == 0); + + return fpregs; +} + int mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) { @@ -240,6 +293,7 @@ mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) tag = dwarf_tag (typedie); } + Dwarf_Word size; switch (tag) { case -1: @@ -258,8 +312,6 @@ mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) case DW_TAG_enumeration_type: case DW_TAG_pointer_type: case DW_TAG_ptr_to_member_type: - { - Dwarf_Word size; if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size, &attr_mem), &size) != 0) { @@ -289,7 +341,7 @@ mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) if (size <= 4*regsize && abi == MIPS_ABI_O32) return nloc_fpregquad; - goto aggregate; + goto large; } } *locp = ABI_LOC(loc_intreg, regsize); @@ -298,18 +350,50 @@ mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp) if (size <= 2*regsize) return nloc_intregpair; - /* Else fall through. Shouldn't happen though (at least with gcc) */ - } + /* Else pass in memory. Shouldn't happen though (at least with gcc) */ + goto large; case DW_TAG_structure_type: case DW_TAG_class_type: case DW_TAG_union_type: - case DW_TAG_array_type: - aggregate: - /* XXX TODO: Can't handle structure return with other ABI's yet :-/ */ - if ((abi != MIPS_ABI_O32) && (abi != MIPS_ABI_O64)) - return -2; + /* Handle special cases for structures <= 128 bytes in newer ABIs */ + if (abi == MIPS_ABI_EABI32 || abi == MIPS_ABI_EABI64 || + abi == MIPS_ABI_N32 || abi == MIPS_ABI_N64) + { + if (dwarf_aggregate_size (typedie, &size) == 0 && size <= 16) + { + /* + * Special case in N64 / N32 - + * structures containing only floats are returned in fp regs. + * Everything else is returned in integer regs. + */ + if (tag != DW_TAG_union_type && + (abi == MIPS_ABI_N32 || abi == MIPS_ABI_N64)) + { + int num_fpregs = get_struct_fpregs(typedie); + if (num_fpregs == 1 || num_fpregs == 2) + { + *locp = loc_fpreg; + if (num_fpregs == 1) + return nloc_fpreg; + else + return nloc_fpregpair; + } + } + + *locp = loc_intreg; + if (size <= 8) + return nloc_intreg; + else + return nloc_intregpair; + } + } + + /* Fallthrough to handle large types */ + case DW_TAG_array_type: + large: + /* Return large structures in memory */ *locp = loc_aggregate; return nloc_aggregate; } -- 2.1.4