Squashed 'third_party/elfutils/' content from commit 555e15e
Change-Id: I61cde98949e47e5c8c09c33260de17f30921be79
git-subtree-dir: third_party/elfutils
git-subtree-split: 555e15ebe8bf1eb33d00747173cfc80cc65648a4
diff --git a/backends/aarch64_retval.c b/backends/aarch64_retval.c
new file mode 100644
index 0000000..1308340
--- /dev/null
+++ b/backends/aarch64_retval.c
@@ -0,0 +1,376 @@
+/* Function return value location for Linux/AArch64 ABI.
+ Copyright (C) 2013 Red Hat, Inc.
+ 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 <stdio.h>
+#include <inttypes.h>
+
+#include <assert.h>
+#include <dwarf.h>
+
+#define BACKEND aarch64_
+#include "libebl_CPU.h"
+
+static int
+skip_until (Dwarf_Die *child, int tag)
+{
+ int i;
+ while (DWARF_TAG_OR_RETURN (child) != tag)
+ if ((i = dwarf_siblingof (child, child)) != 0)
+ /* If there are no members, then this is not a HFA. Errors
+ are propagated. */
+ return i;
+ return 0;
+}
+
+static int
+dwarf_bytesize_aux (Dwarf_Die *die, Dwarf_Word *sizep)
+{
+ int bits;
+ if (((bits = 8 * dwarf_bytesize (die)) < 0
+ && (bits = dwarf_bitsize (die)) < 0)
+ || bits % 8 != 0)
+ return -1;
+
+ *sizep = bits / 8;
+ return 0;
+}
+
+/* HFA (Homogeneous Floating-point Aggregate) is an aggregate type
+ whose members are all of the same floating-point type, which is
+ then base type of this HFA. Instead of being floating-point types
+ directly, members can instead themselves be HFA. Such HFA fields
+ are handled as if their type were HFA base type.
+
+ This function returns 0 if TYPEDIE is HFA, 1 if it is not, or -1 if
+ there were errors. In the former case, *SIZEP contains byte size
+ of the base type (e.g. 8 for IEEE double). *COUNT is set to the
+ number of leaf members of the HFA. */
+static int hfa_type (Dwarf_Die *ftypedie, int tag,
+ Dwarf_Word *sizep, Dwarf_Word *countp);
+
+/* Return 0 if MEMBDIE refers to a member with a floating-point or HFA
+ type, or 1 if it's not. Return -1 for errors. The meaning of the
+ remaining arguments is as documented at hfa_type. */
+static int
+member_is_fp (Dwarf_Die *membdie, Dwarf_Word *sizep, Dwarf_Word *countp)
+{
+ Dwarf_Die typedie;
+ int tag = dwarf_peeled_die_type (membdie, &typedie);
+ switch (tag)
+ {
+ case DW_TAG_base_type:;
+ Dwarf_Word encoding;
+ Dwarf_Attribute attr_mem;
+ if (dwarf_attr_integrate (&typedie, DW_AT_encoding, &attr_mem) == NULL
+ || dwarf_formudata (&attr_mem, &encoding) != 0)
+ return -1;
+
+ switch (encoding)
+ {
+ case DW_ATE_complex_float:
+ *countp = 2;
+ break;
+
+ case DW_ATE_float:
+ *countp = 1;
+ break;
+
+ default:
+ return 1;
+ }
+
+ if (dwarf_bytesize_aux (&typedie, sizep) < 0)
+ return -1;
+
+ *sizep /= *countp;
+ return 0;
+
+ case DW_TAG_structure_type:
+ case DW_TAG_union_type:
+ case DW_TAG_array_type:
+ return hfa_type (&typedie, tag, sizep, countp);
+ }
+
+ return 1;
+}
+
+static int
+hfa_type (Dwarf_Die *ftypedie, int tag, Dwarf_Word *sizep, Dwarf_Word *countp)
+{
+ assert (tag == DW_TAG_structure_type || tag == DW_TAG_class_type
+ || tag == DW_TAG_union_type || tag == DW_TAG_array_type);
+
+ int i;
+ if (tag == DW_TAG_array_type)
+ {
+ Dwarf_Word tot_size;
+ if (dwarf_aggregate_size (ftypedie, &tot_size) < 0)
+ return -1;
+
+ /* For vector types, we don't care about the underlying
+ type, but only about the vector type itself. */
+ bool vec;
+ Dwarf_Attribute attr_mem;
+ if (dwarf_formflag (dwarf_attr_integrate (ftypedie, DW_AT_GNU_vector,
+ &attr_mem), &vec) == 0
+ && vec)
+ {
+ *sizep = tot_size;
+ *countp = 1;
+
+ return 0;
+ }
+
+ if ((i = member_is_fp (ftypedie, sizep, countp)) == 0)
+ {
+ *countp = tot_size / *sizep;
+ return 0;
+ }
+
+ return i;
+ }
+
+ /* Find first DW_TAG_member and determine its type. */
+ Dwarf_Die member;
+ if ((i = dwarf_child (ftypedie, &member) != 0))
+ return i;
+
+ if ((i = skip_until (&member, DW_TAG_member)) != 0)
+ return i;
+
+ *countp = 0;
+ if ((i = member_is_fp (&member, sizep, countp)) != 0)
+ return i;
+
+ while ((i = dwarf_siblingof (&member, &member)) == 0
+ && (i = skip_until (&member, DW_TAG_member)) == 0)
+ {
+ Dwarf_Word size, count;
+ if ((i = member_is_fp (&member, &size, &count)) != 0)
+ return i;
+
+ if (*sizep != size)
+ return 1;
+
+ *countp += count;
+ }
+
+ /* At this point we already have at least one FP member, which means
+ FTYPEDIE is an HFA. So either return 0, or propagate error. */
+ return i < 0 ? i : 0;
+}
+
+static int
+pass_in_gpr (const Dwarf_Op **locp, Dwarf_Word size)
+{
+ static const Dwarf_Op loc[] =
+ {
+ { .atom = DW_OP_reg0 }, { .atom = DW_OP_piece, .number = 8 },
+ { .atom = DW_OP_reg1 }, { .atom = DW_OP_piece, .number = 8 }
+ };
+
+ *locp = loc;
+ return size <= 8 ? 1 : 4;
+}
+
+static int
+pass_by_ref (const Dwarf_Op **locp)
+{
+ static const Dwarf_Op loc[] = { { .atom = DW_OP_breg0 } };
+
+ *locp = loc;
+ return 1;
+}
+
+static int
+pass_hfa (const Dwarf_Op **locp, Dwarf_Word size, Dwarf_Word count)
+{
+ assert (count >= 1 && count <= 4);
+ assert (size == 2 || size == 4 || size == 8 || size == 16);
+
+#define DEFINE_FPREG(NAME, SIZE) \
+ static const Dwarf_Op NAME[] = { \
+ { .atom = DW_OP_regx, .number = 64 }, \
+ { .atom = DW_OP_piece, .number = SIZE }, \
+ { .atom = DW_OP_regx, .number = 65 }, \
+ { .atom = DW_OP_piece, .number = SIZE }, \
+ { .atom = DW_OP_regx, .number = 66 }, \
+ { .atom = DW_OP_piece, .number = SIZE }, \
+ { .atom = DW_OP_regx, .number = 67 }, \
+ { .atom = DW_OP_piece, .number = SIZE } \
+ }
+
+ switch (size)
+ {
+ case 2:;
+ DEFINE_FPREG (loc_hfa_2, 2);
+ *locp = loc_hfa_2;
+ break;
+
+ case 4:;
+ DEFINE_FPREG (loc_hfa_4, 4);
+ *locp = loc_hfa_4;
+ break;
+
+ case 8:;
+ DEFINE_FPREG (loc_hfa_8, 8);
+ *locp = loc_hfa_8;
+ break;
+
+ case 16:;
+ DEFINE_FPREG (loc_hfa_16, 16);
+ *locp = loc_hfa_16;
+ break;
+ }
+#undef DEFINE_FPREG
+
+ return count == 1 ? 1 : 2 * count;
+}
+
+static int
+pass_in_simd (const Dwarf_Op **locp)
+{
+ /* This is like passing single-element HFA. Size doesn't matter, so
+ pretend it's for example double. */
+ return pass_hfa (locp, 8, 1);
+}
+
+int
+aarch64_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 typedie;
+ int tag = dwarf_peeled_die_type (functypedie, &typedie);
+ if (tag <= 0)
+ return tag;
+
+ Dwarf_Word size = (Dwarf_Word)-1;
+
+ /* If the argument type is a Composite Type that is larger than 16
+ bytes, then the argument is copied to memory allocated by the
+ caller and the argument is replaced by a pointer to the copy. */
+ if (tag == DW_TAG_structure_type || tag == DW_TAG_union_type
+ || tag == DW_TAG_class_type || tag == DW_TAG_array_type)
+ {
+ Dwarf_Word base_size, count;
+ switch (hfa_type (&typedie, tag, &base_size, &count))
+ {
+ default:
+ return -1;
+
+ case 0:
+ assert (count > 0);
+ if (count <= 4)
+ return pass_hfa (locp, base_size, count);
+ FALLTHROUGH;
+
+ case 1:
+ /* Not a HFA. */
+ if (dwarf_aggregate_size (&typedie, &size) < 0)
+ return -1;
+ if (size > 16)
+ return pass_by_ref (locp);
+ }
+ }
+
+ if (tag == DW_TAG_base_type
+ || tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
+ {
+ if (dwarf_bytesize_aux (&typedie, &size) < 0)
+ {
+ if (tag == DW_TAG_pointer_type || tag == DW_TAG_ptr_to_member_type)
+ size = 8;
+ else
+ return -1;
+ }
+
+ Dwarf_Attribute attr_mem;
+ 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;
+
+ switch (encoding)
+ {
+ /* If the argument is a Half-, Single-, Double- or Quad-
+ precision Floating-point [...] the argument is allocated
+ to the least significant bits of register v[NSRN]. */
+ case DW_ATE_float:
+ switch (size)
+ {
+ case 2: /* half */
+ case 4: /* sigle */
+ case 8: /* double */
+ case 16: /* quad */
+ return pass_in_simd (locp);
+
+ default:
+ return -2;
+ }
+
+ case DW_ATE_complex_float:
+ switch (size)
+ {
+ case 8: /* float _Complex */
+ case 16: /* double _Complex */
+ case 32: /* long double _Complex */
+ return pass_hfa (locp, size / 2, 2);
+
+ default:
+ return -2;
+ }
+
+ /* If the argument is an Integral or Pointer Type, the
+ size of the argument is less than or equal to 8 bytes
+ [...] the argument is copied to the least significant
+ bits in x[NGRN]. */
+ case DW_ATE_boolean:
+ case DW_ATE_signed:
+ case DW_ATE_unsigned:
+ case DW_ATE_unsigned_char:
+ case DW_ATE_signed_char:
+ return pass_in_gpr (locp, size);
+ }
+
+ return -2;
+ }
+ else
+ return pass_in_gpr (locp, size);
+ }
+
+ *locp = NULL;
+ return 0;
+}