[v3,6/6] backends: Add register_info, return_value_location, core_note function on mips

diff --git a/backends/Makefile.am b/backends/Makefile.am
index 5e7b7f21..7c7f3351 100644
--- a/backends/Makefile.am
+++ b/backends/Makefile.am
@@ -103,7 +103,8 @@  loongarch_SRCS = loongarch_init.c loongarch_symbol.c loongarch_cfi.c \
 arc_SRCS = arc_init.c arc_symbol.c
 
 mips_SRCS = mips_init.c mips_symbol.c mips_attrs.c mips_initreg.c \
-	    mips_cfi.c mips_unwind.c
+	    mips_cfi.c mips_unwind.c mips_regs.c mips_retval.c \
+	    mips_corenote.c
 
 libebl_backends_a_SOURCES = $(i386_SRCS) $(sh_SRCS) $(x86_64_SRCS) \
 			    $(ia64_SRCS) $(alpha_SRCS) $(arm_SRCS) \
diff --git a/backends/mips_corenote.c b/backends/mips_corenote.c
new file mode 100644
index 00000000..aeadeb17
--- /dev/null
+++ b/backends/mips_corenote.c
@@ -0,0 +1,85 @@ 
+/* MIPS specific core note handling.
+   Copyright (C) 2024 CIP United 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 <elf.h>
+#include <inttypes.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <sys/time.h>
+
+#define BACKEND	mips_
+#include "libebl_CPU.h"
+
+#define BITS 64
+#ifndef BITS
+# define BITS 		32
+#else
+# define BITS 		64
+#endif
+
+#define PRSTATUS_REGS_SIZE	(45 * (BITS / 8))
+static const Ebl_Register_Location prstatus_regs[] =
+  {
+    { .offset = 0, .regno = 0, .count = (BITS == 32 ? 40 : 34), .bits = BITS },
+    { .offset = BITS/8 * (BITS == 32 ? 41 : 35), .regno = (BITS == 32 ? 41 : 35), .count = (BITS == 32 ? 4 : 10), .bits = BITS },
+  };
+
+#define PRSTATUS_REGSET_ITEMS						\
+  {									\
+    .name = "pc", .type = ELF_T_ADDR, .format = 'x',			\
+    .offset = offsetof (struct EBLHOOK(prstatus), pr_reg) + ((BITS/8) * (BITS == 32 ? 40 : 34)),	\
+    .group = "register",						\
+    .pc_register = true							\
+  }
+
+#if BITS == 32
+# define ULONG			uint32_t
+# define ALIGN_ULONG		4
+# define TYPE_ULONG		ELF_T_WORD
+#define TYPE_LONG		ELF_T_SWORD
+#else
+#define ULONG			uint64_t
+#define ALIGN_ULONG		8
+#define TYPE_ULONG		ELF_T_XWORD
+#define TYPE_LONG		ELF_T_SXWORD
+#endif
+#define PID_T			int32_t
+#define	UID_T			uint32_t
+#define	GID_T			uint32_t
+#define ALIGN_PID_T		4
+#define ALIGN_UID_T		4
+#define ALIGN_GID_T		4
+#define TYPE_PID_T		ELF_T_SWORD
+#define TYPE_UID_T		ELF_T_WORD
+#define TYPE_GID_T		ELF_T_WORD
+
+#include "linux-core-note.c"
diff --git a/backends/mips_init.c b/backends/mips_init.c
index 1a2456b1..711a934e 100644
--- a/backends/mips_init.c
+++ b/backends/mips_init.c
@@ -61,6 +61,9 @@  mips_init (Elf *elf __attribute__ ((unused)),
   HOOK (eh, set_initial_registers_tid);
   HOOK (eh, abi_cfi);
   HOOK (eh, unwind);
+  HOOK (eh, register_info);
+  HOOK (eh, return_value_location);
+  HOOK (eh, core_note);
   eh->frame_nregs = 71;
   return eh;
 }
diff --git a/backends/mips_regs.c b/backends/mips_regs.c
new file mode 100644
index 00000000..4a1f8c50
--- /dev/null
+++ b/backends/mips_regs.c
@@ -0,0 +1,135 @@ 
+/* Register names and numbers for mips DWARF.
+   Copyright (C) 2006 Red Hat, Inc.
+   Copyright (C) 2024 CIP United 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 <assert.h>
+#include <dwarf.h>
+#include <string.h>
+
+#define BACKEND mips_
+#include "libebl_CPU.h"
+#include <system.h>
+ssize_t
+mips_register_info (Ebl *ebl __attribute__ ((unused)),
+		      int regno, char *name, size_t namelen,
+		      const char **prefix, const char **setname,
+		      int *bits, int *type)
+{
+  if (name == NULL)
+    return 72;
+
+  if (regno < 0 || regno > 71 || namelen < 4)
+    return -1;
+
+  *prefix = "$";
+  if (regno < 38)
+    {
+      *setname = "integer";
+      *type = DW_ATE_signed;
+      *bits = 32;
+    }
+  else
+    {
+      *setname = "FPU";
+      *type = DW_ATE_float;
+      *bits = 64;
+    }
+
+  if (regno < 32)
+    {
+      if (regno < 10)
+	{
+	  name[0] = regno + '0';
+	  namelen = 1;
+	}
+      else
+	{
+	  name[0] = (regno / 10) + '0';
+	  name[1] = (regno % 10) + '0';
+	  namelen = 2;
+	}
+      if (regno == 28 || regno == 29 || regno == 31)
+	*type = DW_ATE_address;
+    }
+  else if (regno == 32)
+    {
+      return stpcpy (name, "lo") + 1 - name;
+    }
+  else if (regno == 33)
+    {
+      return stpcpy (name, "hi") + 1 - name;
+    }
+  else if (regno == 34)
+    {
+      return stpcpy (name, "pc") + 1 - name;
+    }
+  else if (regno == 35)
+    {
+      *type = DW_ATE_address;
+      return stpcpy (name, "bad") + 1 - name;
+    }
+  else if (regno == 36)
+    {
+      return stpcpy (name, "sr") + 1 - name;
+    }
+  else if (regno == 37)
+    {
+      *type = DW_ATE_address;
+      return stpcpy (name, "cause") + 1 - name;
+    }
+  else if (regno < 70)
+    {
+      name[0] = 'f';
+      if (regno < 38 + 10)
+      {
+	name[1] = (regno - 38) + '0';
+	namelen = 2;
+      }
+      else
+      {
+	name[1] = (regno - 38) / 10 + '0';
+	name[2] = (regno - 38) % 10 + '0';
+	namelen = 3;
+      }
+    }
+  else if (regno == 70)
+    {
+      return stpcpy (name, "fsr") + 1 - name;
+    }
+  else if (regno == 71)
+    {
+      return stpcpy (name, "fir") + 1 - name;
+    }
+
+  name[namelen++] = '\0';
+  return namelen;
+}
diff --git a/backends/mips_retval.c b/backends/mips_retval.c
new file mode 100644
index 00000000..2b697c08
--- /dev/null
+++ b/backends/mips_retval.c
@@ -0,0 +1,196 @@ 
+/* Function return value location for Linux/mips ABI.
+   Copyright (C) 2005 Red Hat, Inc.
+   Copyright (C) 2024 CIP United 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 <assert.h>
+#include <dwarf.h>
+#include <string.h>
+#include <elf.h>
+#include <stdio.h>
+
+#define BACKEND mips_
+#include "libebl_CPU.h"
+#include "libdwP.h"
+#include <stdio.h>
+
+/* $v0 or pair $v0, $v1 */
+static const Dwarf_Op loc_intreg_o32[] =
+  {
+    { .atom = DW_OP_reg2 }, { .atom = DW_OP_piece, .number = 4 },
+    { .atom = DW_OP_reg3 }, { .atom = DW_OP_piece, .number = 4 },
+  };
+
+static const Dwarf_Op loc_intreg[] =
+  {
+    { .atom = DW_OP_reg2 }, { .atom = DW_OP_piece, .number = 8 },
+    { .atom = DW_OP_reg3 }, { .atom = DW_OP_piece, .number = 8 },
+  };
+#define nloc_intreg	1
+#define nloc_intregpair	4
+
+/* $f0 (float), or pair $f0, $f1 (double).
+ * f2/f3 are used for COMPLEX (= 2 doubles) returns in Fortran */
+static const Dwarf_Op loc_fpreg_o32[] =
+  {
+    { .atom = DW_OP_regx, .number = 32 }, { .atom = DW_OP_piece, .number = 4 },
+    { .atom = DW_OP_regx, .number = 33 }, { .atom = DW_OP_piece, .number = 4 },
+    { .atom = DW_OP_regx, .number = 34 }, { .atom = DW_OP_piece, .number = 4 },
+    { .atom = DW_OP_regx, .number = 35 }, { .atom = DW_OP_piece, .number = 4 },
+  };
+
+/* $f0, or pair $f0, $f2.  */
+static const Dwarf_Op loc_fpreg[] =
+  {
+    { .atom = DW_OP_regx, .number = 32 }, { .atom = DW_OP_piece, .number = 8 },
+    { .atom = DW_OP_regx, .number = 34 }, { .atom = DW_OP_piece, .number = 8 },
+  };
+#define nloc_fpreg  1
+#define nloc_fpregpair 4
+#define nloc_fpregquad 8
+
+/* 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 $v0.  */
+static const Dwarf_Op loc_aggregate[] =
+  {
+    { .atom = DW_OP_breg2, .number = 0 }
+  };
+#define nloc_aggregate 1
+
+int
+mips_return_value_location (Dwarf_Die *functypedie, const Dwarf_Op **locp)
+{
+  unsigned int regsize = (gelf_getclass (functypedie->cu->dbg->elf) == ELFCLASS32 ) ? 4 : 8;
+  if (!regsize)
+    return -2;
+
+  /* Start with the function's type, and get the DW_AT_type attribute,
+     which is the type of the return value.  */
+
+  Dwarf_Attribute attr_mem;
+  Dwarf_Attribute *attr = dwarf_attr_integrate (functypedie, DW_AT_type, &attr_mem);
+  if (attr == NULL)
+    /* The function has no return value, like a `void' function in C.  */
+    return 0;
+
+  Dwarf_Die die_mem;
+  Dwarf_Die *typedie = dwarf_formref_die (attr, &die_mem);
+  int tag = dwarf_tag (typedie);
+
+  /* Follow typedefs and qualifiers to get to the actual type.  */
+  while (tag == DW_TAG_typedef
+	 || tag == DW_TAG_const_type || tag == DW_TAG_volatile_type
+	 || tag == DW_TAG_restrict_type)
+    {
+      attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
+      typedie = dwarf_formref_die (attr, &die_mem);
+      tag = dwarf_tag (typedie);
+    }
+
+  switch (tag)
+    {
+    case -1:
+      return -1;
+
+    case DW_TAG_subrange_type:
+      if (! dwarf_hasattr_integrate (typedie, DW_AT_byte_size))
+	{
+	  attr = dwarf_attr_integrate (typedie, DW_AT_type, &attr_mem);
+	  typedie = dwarf_formref_die (attr, &die_mem);
+	  tag = dwarf_tag (typedie);
+	}
+      /* Fall through.  */
+      FALLTHROUGH;
+
+    case DW_TAG_base_type:
+    case DW_TAG_enumeration_type:
+    CASE_POINTER:
+      {
+	Dwarf_Word size;
+	if (dwarf_formudata (dwarf_attr_integrate (typedie, DW_AT_byte_size,
+					 &attr_mem), &size) != 0)
+	  {
+	    if (dwarf_is_pointer (tag))
+	      size = regsize;
+	    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;
+
+#define ARCH_LOC(loc, regsize) ((regsize) == 4 ? (loc ## _o32) : (loc))
+
+	    if (encoding == DW_ATE_float)
+	      {
+		*locp = ARCH_LOC(loc_fpreg, regsize);
+		if (size <= regsize)
+		  return nloc_fpreg;
+
+		if (size <= 2*regsize)
+		  return nloc_fpregpair;
+
+		if (size <= 4*regsize)
+		  return nloc_fpregquad;
+
+		goto aggregate;
+	      }
+	  }
+	*locp = ARCH_LOC(loc_intreg, regsize);
+	if (size <= regsize)
+	  return nloc_intreg;
+	if (size <= 2*regsize)
+	  return nloc_intregpair;
+
+	/* Else fall through. Shouldn't happen though (at least with gcc) */
+      }
+      FALLTHROUGH;
+
+    case DW_TAG_structure_type:
+    case DW_TAG_class_type:
+    case DW_TAG_union_type:
+    case DW_TAG_array_type:
+    aggregate:
+      *locp = loc_aggregate;
+      return nloc_aggregate;
+    case DW_TAG_unspecified_type:
+      return 0;
+    }
+
+  /* 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;
+}