From fdaab18a65ed2529656baa64cb6169f34d7e507b Mon Sep 17 00:00:00 2001
From: James Cowgill <james410@cowgill.org.uk>
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 <james410@cowgill.org.uk>
Upstream-Status: Pending [from debian]
Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
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