[RFC] Add v850e3v5 and RH850 ABI support to v850-tdep.c

[Kevin Buettner <kevinb at redhat dot com>]

As stated in the subject line, this patch adds v850e3v5 and RH850 ABI
support to v850-tdep.c.

I'll wait a few days for comments before checking it in.

Kevin

	* v850-tdep.c (elf-bfd.h, elf/v850.h): Include.
	(R_149_REGNUM, E_NUM_OF_V850E2_REGS, E_SELID_1_R0_REGNUM)
	(E_SELID_1_R31_REGNUM, E_SELID_2_R0_REGNUM, E_SELID_2_R31_REGNUM)
	(E_SELID_3_R0_REGNUM, E_SELID_3_R31_REGNUM, E_SELID_4_R0_REGNUM)
	(E_SELID_4_R31_REGNUM, E_SELID_5_R0_REGNUM, E_SELID_5_R31_REGNUM)
	(E_SELID_6_R0_REGNUM, E_SELID_6_R31_REGNUM, E_SELID_7_R0_REGNUM, E_SELID_7_R31_REGNUM)
	(E_VR0_REGNUM, E_VR31_REGNUM, E_NUM_OF_V850E3V5_REGS): Define.
	(v850_abi, V850_ABI_GCC, V850_ABI_RH850): New enum and constants.
	(gdbarch_tdep): New struct.
	(v850e2_register_name): Use E_NUM_OF_V850E2_REGS instead of
	E_NUM_REGS.
	(v850e3v5_register_name): New function.
	(v850_register_type): v850e3v5 vector registers are 64-bits wide.
	(v850_use_struct_convention): Add `gdbarch' parameter.  Add new
	code handling the struct return conventions for the RH850 ABI.
	Update all callers.
	(v850_eight_byte_align_p): New function.
	(v850_push_call_dummy): Push structs by value, not by reference
	for the RH850 ABI.  Add support for eight byte alignment.
	(v850_dbtrap_breakpoint_from_pc): New function.
	(v850_gdbarch_init): Add ABI detection code.  Register
	v850e3v5_register_name for the v850e3v5 architecture.  Set the
	number of registers for v850e3v5.  Register
	v850_dbtrap_breakpoint_from_pc as appropriate.
	(_initialize_gdbarch_init): Registration bfd_arch_v850_rh850.

Index: v850-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/v850-tdep.c,v
retrieving revision 1.125
diff -u -p -r1.125 v850-tdep.c
--- v850-tdep.c	2 Mar 2013 18:26:30 -0000	1.125
+++ v850-tdep.c	25 Apr 2013 23:12:22 -0000
@@ -32,6 +32,8 @@
 #include "regcache.h"
 #include "dis-asm.h"
 #include "osabi.h"
+#include "elf-bfd.h"
+#include "elf/v850.h"
 
 enum
   {
@@ -197,7 +199,39 @@ enum
     E_R146_REGNUM,
     E_R147_REGNUM,
     E_R148_REGNUM,
-    E_NUM_REGS
+    E_R149_REGNUM,
+    E_NUM_OF_V850E2_REGS,
+
+    /* v850e3v5 system registers, selID 1 thru 7.  */
+    E_SELID_1_R0_REGNUM = E_NUM_OF_V850E2_REGS,
+    E_SELID_1_R31_REGNUM = E_SELID_1_R0_REGNUM + 31,
+
+    E_SELID_2_R0_REGNUM,
+    E_SELID_2_R31_REGNUM = E_SELID_2_R0_REGNUM + 31,
+
+    E_SELID_3_R0_REGNUM,
+    E_SELID_3_R31_REGNUM = E_SELID_3_R0_REGNUM + 31,
+
+    E_SELID_4_R0_REGNUM,
+    E_SELID_4_R31_REGNUM = E_SELID_4_R0_REGNUM + 31,
+
+    E_SELID_5_R0_REGNUM,
+    E_SELID_5_R31_REGNUM = E_SELID_5_R0_REGNUM + 31,
+
+    E_SELID_6_R0_REGNUM,
+    E_SELID_6_R31_REGNUM = E_SELID_6_R0_REGNUM + 31,
+
+    E_SELID_7_R0_REGNUM,
+    E_SELID_7_R31_REGNUM = E_SELID_7_R0_REGNUM + 31,
+
+    /* v850e3v5 vector registers.  */
+    E_VR0_REGNUM,
+    E_VR31_REGNUM = E_VR0_REGNUM + 31,
+
+    E_NUM_OF_V850E3V5_REGS,
+
+    /* Total number of possible registers.  */
+    E_NUM_REGS = E_NUM_OF_V850E3V5_REGS
   };
 
 enum
@@ -211,6 +245,38 @@ enum
   E_MAX_RETTYPE_SIZE_IN_REGS = 2 * v850_reg_size
 };
 
+/* When v850 support was added to GCC in the late nineties, the intention
+   was to follow the Green Hills ABI for v850.  In fact, the authors of
+   that support at the time thought that they were doing so.  As far as
+   I can tell, the calling conventions are correct, but the return value
+   conventions were not quite right.  Over time, the return value code
+   in this file was modified to mostly reflect what GCC was actually
+   doing instead of to actually follow the Green Hills ABI as it did
+   when the code was first written.
+
+   Renesas defined the RH850 ABI which they use in their compiler.  It
+   is similar to the original Green Hills ABI with some minor
+   differences.  */
+
+enum v850_abi
+{
+  V850_ABI_GCC,
+  V850_ABI_RH850
+};
+
+/* Architecture specific data.  */
+
+struct gdbarch_tdep
+{
+  /* Fields from the ELF header.  */
+  int e_flags;
+  int e_machine;
+
+  /* Which ABI are we using?  */
+  enum v850_abi abi;
+  int eight_byte_align;
+};
+
 struct v850_frame_cache
 { 
   /* Base address.  */
@@ -311,11 +377,110 @@ v850e2_register_name (struct gdbarch *gd
     "", "", "", "", "", "", "", "",
     "", "", "", "fpspc"
   };
-  if (regnum < 0 || regnum >= E_NUM_REGS)
+  if (regnum < 0 || regnum >= E_NUM_OF_V850E2_REGS)
     return NULL;
   return v850e2_reg_names[regnum];
 }
 
+/* Implement the "register_name" gdbarch method for v850e3v5.  */
+
+static const char *
+v850e3v5_register_name (struct gdbarch *gdbarch, int regnum)
+{
+  static const char *v850e3v5_reg_names[] =
+  {
+    /* General purpose registers.  */
+    "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
+    "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
+    "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
+    "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
+
+    /* selID 0, not including FPU registers.  The FPU registers are
+       listed later on.  */
+    "eipc", "eipsw", "fepc", "fepsw", "", "psw", "" /* fpsr */, "" /* fpepc */,
+    "" /* fpst */, "" /* fpcc */, "" /* fpcfg */, "" /* fpec */, "sesr", "eiic", "feic", "",
+    "ctpc", "ctpsw", "", "", "ctbp", "", "", "",
+    "", "", "", "", "eiwr", "fewr", "", "bsel",
+
+
+    /* PC.  */
+    "pc", "",
+
+    /* v850e2 MPV bank.  */
+    "", "", "", "", "", "", "", "",
+    "", "", "", "", "", "", "", "",
+    "", "", "", "", "", "", "", "",
+    "", "", "", "",
+
+    /* Skip v850e2 MPU bank.  It's tempting to reuse these, but we need
+       32 entries for this bank.  */
+    "", "", "", "", "", "", "", "",
+    "", "", "", "", "", "", "", "",
+    "", "", "", "", "", "", "", "",
+    "", "", "", "",
+
+    /* FPU system registers.  These are actually in selID 0, but
+       are placed here to preserve register numbering compatibility
+       with previous architectures.  */
+    "", "", "", "", "", "", "fpsr", "fpepc",
+    "fpst", "fpcc", "fpcfg", "fpec", "", "", "", "",
+    "", "", "", "", "", "", "", "",
+    "", "", "", "",
+
+    /* selID 1.  */
+    "mcfg0", "mcfg1", "rbase", "ebase", "intbp", "mctl", "pid", "fpipr",
+    "", "", "tcsel", "sccfg", "scbp", "hvccfg", "hvcbp", "vsel",
+    "vmprt0", "vmprt1", "vmprt2", "", "", "", "", "vmscctl",
+    "vmsctbl0", "vmsctbl1", "vmsctbl2", "vmsctbl3", "", "", "", "",
+
+    /* selID 2.  */
+    "htcfg0", "", "", "", "", "htctl", "mea", "asid",
+    "mei", "ispr", "pmr", "icsr", "intcfg", "", "", "",
+    "tlbsch", "", "", "", "", "", "", "htscctl",
+    "htsctbl0", "htsctbl1", "htsctbl2", "htsctbl3", "htsctbl4", "htsctbl5", "htsctbl6", "htsctbl7",
+
+    /* selID 3.  */
+    "", "", "", "", "", "", "", "",
+    "", "", "", "", "", "", "", "",
+    "", "", "", "", "", "", "", "",
+    "", "", "", "", "", "", "", "",
+
+    /* selID 4.  */
+    "tlbidx", "", "", "", "telo0", "telo1", "tehi0", "tehi1",
+    "", "", "tlbcfg", "", "bwerrl", "bwerrh", "brerrl", "brerrh",
+    "ictagl", "ictagh", "icdatl", "icdath", "dctagl", "dctagh", "dcdatl", "dcdath",
+    "icctrl", "dcctrl", "iccfg", "dccfg", "icerr", "dcerr", "", "",
+
+    /* selID 5.  */
+    "mpm", "mprc", "", "", "mpbrgn", "mptrgn", "", "",
+    "mca", "mcs", "mcc", "mcr", "", "", "", "",
+    "", "", "", "", "mpprt0", "mpprt1", "mpprt2", "",
+    "", "", "", "", "", "", "", "",
+
+    /* selID 6.  */
+    "mpla0", "mpua0", "mpat0", "", "mpla1", "mpua1", "mpat1", "",
+    "mpla2", "mpua2", "mpat2", "", "mpla3", "mpua3", "mpat3", "",
+    "mpla4", "mpua4", "mpat4", "", "mpla5", "mpua5", "mpat5", "",
+    "mpla6", "mpua6", "mpat6", "", "mpla7", "mpua7", "mpat7", "",
+
+    /* selID 7.  */
+    "mpla8", "mpua8", "mpat8", "", "mpla9", "mpua9", "mpat9", "",
+    "mpla10", "mpua10", "mpat10", "", "mpla11", "mpua11", "mpat11", "",
+    "mpla12", "mpua12", "mpat12", "", "mpla13", "mpua13", "mpat13", "",
+    "mpla14", "mpua14", "mpat14", "", "mpla15", "mpua15", "mpat15", "",
+
+    /* Vector Registers */
+    "vr0", "vr1", "vr2", "vr3", "vr4", "vr5", "vr6", "vr7",
+    "vr8", "vr9", "vr10", "vr11", "vr12", "vr13", "vr14", "vr15",
+    "vr16", "vr17", "vr18", "vr19", "vr20", "vr21", "vr22", "vr23",
+    "vr24", "vr25", "vr26", "vr27", "vr28", "vr29", "vr30", "vr31",
+  };
+
+  if (regnum < 0 || regnum >= E_NUM_OF_V850E3V5_REGS)
+    return NULL;
+  return v850e3v5_reg_names[regnum];
+}
+
 /* Returns the default type for register N.  */
 
 static struct type *
@@ -323,6 +488,8 @@ v850_register_type (struct gdbarch *gdba
 {
   if (regnum == E_PC_REGNUM)
     return builtin_type (gdbarch)->builtin_func_ptr;
+  else if (E_VR0_REGNUM <= regnum && regnum <= E_VR31_REGNUM)
+    return builtin_type (gdbarch)->builtin_uint64;
   return builtin_type (gdbarch)->builtin_int32;
 }
 
@@ -336,11 +503,19 @@ v850_type_is_scalar (struct type *t)
 
 /* Should call_function allocate stack space for a struct return?  */
 static int
-v850_use_struct_convention (struct type *type)
+v850_use_struct_convention (struct gdbarch *gdbarch, struct type *type)
 {
   int i;
   struct type *fld_type, *tgt_type;
 
+  if (gdbarch_tdep (gdbarch)->abi == V850_ABI_RH850)
+    {
+      if (v850_type_is_scalar (type) && TYPE_LENGTH(type) <= 8)
+	return 0;
+
+      /* Structs are never returned in registers for this ABI.  */
+      return 1;
+    }
   /* 1. The value is greater than 8 bytes -> returned by copying.  */
   if (TYPE_LENGTH (type) > 8)
     return 1;
@@ -397,7 +572,7 @@ v850_use_struct_convention (struct type 
       for (i = 0; i < TYPE_NFIELDS (type); ++i)
         {
 	  fld_type = TYPE_FIELD_TYPE (type, 0);
-	  if (!v850_use_struct_convention (fld_type))
+	  if (!v850_use_struct_convention (gdbarch, fld_type))
 	    return 0;
 	}
     }
@@ -788,6 +963,28 @@ v850_skip_prologue (struct gdbarch *gdba
   return pc;
 }
 
+/* Return 1 if the data structure has any 8-byte fields that'll require
+   the entire data structure to be aligned.  Otherwise, return 0.  */
+static int
+v850_eight_byte_align_p (struct type *type)
+{
+  type = check_typedef (type);
+
+  if (v850_type_is_scalar (type))
+    return (TYPE_LENGTH (type) == 8);
+  else
+    {
+      int i;
+
+      for (i = 0; i < TYPE_NFIELDS (type); i++)
+	{
+	  if (v850_eight_byte_align_p (TYPE_FIELD_TYPE (type, i)))
+	    return 1;
+	}
+    }
+  return 0;
+}
+
 static CORE_ADDR
 v850_frame_align (struct gdbarch *ignore, CORE_ADDR sp)
 {
@@ -820,6 +1017,9 @@ v850_push_dummy_call (struct gdbarch *gd
   int len = 0;
   int stack_offset;
 
+  if (gdbarch_tdep (gdbarch)->abi == V850_ABI_RH850)
+    stack_offset = 0;
+  else
   /* The offset onto the stack at which we will start copying parameters
      (after the registers are used up) begins at 16 rather than at zero.
      That's how the ABI is defined, though there's no indication that these
@@ -847,6 +1047,7 @@ v850_push_dummy_call (struct gdbarch *gd
       gdb_byte valbuf[v850_reg_size];
 
       if (!v850_type_is_scalar (value_type (*args))
+         && gdbarch_tdep (gdbarch)->abi == V850_ABI_GCC
 	  && TYPE_LENGTH (value_type (*args)) > E_MAX_RETTYPE_SIZE_IN_REGS)
 	{
 	  store_unsigned_integer (valbuf, 4, byte_order,
@@ -860,6 +1061,15 @@ v850_push_dummy_call (struct gdbarch *gd
 	  val = (gdb_byte *) value_contents (*args);
 	}
 
+      if (gdbarch_tdep (gdbarch)->eight_byte_align
+          && v850_eight_byte_align_p (value_type (*args)))
+        {
+	  if (argreg <= E_ARGLAST_REGNUM && (argreg & 1))
+	    argreg++;
+	  else if (stack_offset & 0x4)
+	    stack_offset += 4;
+	}
+
       while (len > 0)
 	if (argreg <= E_ARGLAST_REGNUM)
 	  {
@@ -944,7 +1154,7 @@ v850_return_value (struct gdbarch *gdbar
 		   struct type *type, struct regcache *regcache,
 		   gdb_byte *readbuf, const gdb_byte *writebuf)
 {
-  if (v850_use_struct_convention (type))
+  if (v850_use_struct_convention (gdbarch, type))
     return RETURN_VALUE_STRUCT_CONVENTION;
   if (writebuf)
     v850_store_return_value (type, regcache, writebuf);
@@ -961,6 +1171,17 @@ v850_breakpoint_from_pc (struct gdbarch 
   return breakpoint;
 }
 
+/* Implement software breakpoints by using the dbtrap instruction.  Older
+   architectures had no such instruction.  For those, an unconditional branch
+   to self instruction is used.  */
+const static unsigned char *
+v850_dbtrap_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr, int *lenptr)
+{
+  static unsigned char breakpoint[] = { 0x40, 0xf8 };
+  *lenptr = sizeof (breakpoint);
+  return breakpoint;
+}
+
 static struct v850_frame_cache *
 v850_alloc_frame_cache (struct frame_info *this_frame)
 {
@@ -1120,12 +1341,51 @@ static struct gdbarch *
 v850_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
+  struct gdbarch_tdep *tdep;
+  int e_flags, e_machine;
 
-  /* Change the register names based on the current machine type.  */
-  if (info.bfd_arch_info->arch != bfd_arch_v850)
-    return NULL;
+  /* Extract the elf_flags if available.  */
+  if (info.abfd != NULL
+      && bfd_get_flavour (info.abfd) == bfd_target_elf_flavour)
+    {
+      e_flags = elf_elfheader (info.abfd)->e_flags;
+      e_machine = elf_elfheader (info.abfd)->e_machine;
+    }
+  else
+    {
+      e_flags = 0;
+      e_machine = 0;
+    }
 
-  gdbarch = gdbarch_alloc (&info, NULL);
+
+  /* Try to find the architecture in the list of already defined
+     architectures.  */
+  for (arches = gdbarch_list_lookup_by_info (arches, &info);
+       arches != NULL;
+       arches = gdbarch_list_lookup_by_info (arches->next, &info))
+    {
+      if (gdbarch_tdep (arches->gdbarch)->e_flags != e_flags
+          || gdbarch_tdep (arches->gdbarch)->e_machine != e_machine)
+	continue;
+
+      return arches->gdbarch;
+    }
+  tdep = (struct gdbarch_tdep *) xmalloc (sizeof (struct gdbarch_tdep));
+  tdep->e_flags = e_flags;
+  tdep->e_machine = e_machine;
+
+  switch (tdep->e_machine)
+    {
+    case EM_V800:
+      tdep->abi = V850_ABI_RH850;
+      break;
+    default:
+      tdep->abi = V850_ABI_GCC;
+      break;
+    }
+
+  tdep->eight_byte_align = (tdep->e_flags & EF_RH850_DATA_ALIGN8) ? 1 : 0;
+  gdbarch = gdbarch_alloc (&info, tdep);
 
   switch (info.bfd_arch_info->mach)
     {
@@ -1143,6 +1403,10 @@ v850_gdbarch_init (struct gdbarch_info i
       set_gdbarch_register_name (gdbarch, v850e2_register_name);
       set_gdbarch_num_regs (gdbarch, E_NUM_REGS);
       break;
+    case bfd_mach_v850e3v5:
+      set_gdbarch_register_name (gdbarch, v850e3v5_register_name);
+      set_gdbarch_num_regs (gdbarch, E_NUM_OF_V850E3V5_REGS);
+      break;
     }
 
   set_gdbarch_num_pseudo_regs (gdbarch, 0);
@@ -1166,7 +1430,17 @@ v850_gdbarch_init (struct gdbarch_info i
   set_gdbarch_addr_bit (gdbarch, 4 * TARGET_CHAR_BIT);
 
   set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
-  set_gdbarch_breakpoint_from_pc (gdbarch, v850_breakpoint_from_pc);
+  switch (info.bfd_arch_info->mach)
+    {
+    case bfd_mach_v850e2:
+    case bfd_mach_v850e2v3:
+    case bfd_mach_v850e3v5:
+      set_gdbarch_breakpoint_from_pc (gdbarch, v850_dbtrap_breakpoint_from_pc);
+      break;
+    default:
+      set_gdbarch_breakpoint_from_pc (gdbarch, v850_breakpoint_from_pc);
+      break;
+    }
 
   set_gdbarch_return_value (gdbarch, v850_return_value);
   set_gdbarch_push_dummy_call (gdbarch, v850_push_dummy_call);
@@ -1195,4 +1469,5 @@ void
 _initialize_v850_tdep (void)
 {
   register_gdbarch_init (bfd_arch_v850, v850_gdbarch_init);
+  register_gdbarch_init (bfd_arch_v850_rh850, v850_gdbarch_init);
 }