[PATCH]: Bugfixes to v850-tdep.c
Corinna Vinschen
vinschen@redhat.com
Tue Jun 11 00:08:00 GMT 2002
Hi,
I've added some tweaks to the v850 code to match gcc's somewhat
headstrong handling of the struct convention and fixed a bug
I've introduced while changing the code to multi-arch.
Corinna
2002-06-11 Corinna Vinschen <vinschen@redhat.com>
* v850-tdep.c (v850_type_is_scalar): New function.
(v850_use_struct_convention): Match current gcc implementation
as close as possible.
(v850_push_arguments): Fix stack_offset handling. Don't write
struct_addr into register. This is done by v850_store_struct_return.
(v850_extract_return_value): Care for structs.
(v850_store_return_value): Ditto.
(v850_store_struct_return): Actually write address.
Index: v850-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/v850-tdep.c,v
retrieving revision 1.15
diff -u -p -r1.15 v850-tdep.c
--- v850-tdep.c 16 May 2002 11:43:06 -0000 1.15
+++ v850-tdep.c 11 Jun 2002 06:57:39 -0000
@@ -123,6 +123,12 @@ enum
E_ALL_REGS_SIZE = (E_NUM_REGS) * v850_reg_size
};
+/* Size of return datatype which fits into all return registers. */
+enum
+{
+ E_MAX_RETTYPE_SIZE_IN_REGS = 2 * v850_reg_size
+};
+
static LONGEST call_dummy_nil[] = {0};
static char *v850_generic_reg_names[] =
@@ -266,11 +272,90 @@ v850_reg_virtual_type (int regnum)
return builtin_type_int32;
}
+static int
+v850_type_is_scalar (struct type *t)
+{
+ return (TYPE_CODE (t) != TYPE_CODE_STRUCT
+ && TYPE_CODE (t) != TYPE_CODE_UNION
+ && TYPE_CODE (t) != TYPE_CODE_ARRAY);
+}
+
/* Should call_function allocate stack space for a struct return? */
-int
+static int
v850_use_struct_convention (int gcc_p, struct type *type)
{
- return (TYPE_NFIELDS (type) > 1 || TYPE_LENGTH (type) > 4);
+ /* According to ABI:
+ * return TYPE_LENGTH (type) > 8);
+ */
+
+ /* Current implementation in gcc: */
+
+ int i;
+ struct type *fld_type, *tgt_type;
+
+ /* 1. The value is greater than 8 bytes -> returned by copying */
+ if (TYPE_LENGTH (type) > 8)
+ return 1;
+
+ /* 2. The value is a single basic type -> returned in register */
+ if (v850_type_is_scalar (type))
+ return 0;
+
+ /* The value is a structure or union with a single element
+ * and that element is either a single basic type or an array of
+ * a single basic type whoes size is greater than or equal to 4
+ * -> returned in register */
+ if ((TYPE_CODE (type) == TYPE_CODE_STRUCT
+ || TYPE_CODE (type) == TYPE_CODE_UNION)
+ && TYPE_NFIELDS (type) == 1)
+ {
+ fld_type = TYPE_FIELD_TYPE (type, 0);
+ if (v850_type_is_scalar (fld_type) && TYPE_LENGTH (fld_type) >= 4)
+ return 0;
+
+ if (TYPE_CODE (fld_type) == TYPE_CODE_ARRAY)
+ {
+ tgt_type = TYPE_TARGET_TYPE (fld_type);
+ if (v850_type_is_scalar (tgt_type) && TYPE_LENGTH (tgt_type) >= 4)
+ return 0;
+ }
+ }
+
+ /* The value is a structure whose first element is an integer or
+ * a float, and which contains no arrays of more than two elements
+ * -> returned in register */
+ if (TYPE_CODE (type) == TYPE_CODE_STRUCT
+ && v850_type_is_scalar (TYPE_FIELD_TYPE (type, 0))
+ && TYPE_LENGTH (TYPE_FIELD_TYPE (type, 0)) == 4)
+ {
+ for (i = 1; i < TYPE_NFIELDS (type); ++i)
+ {
+ fld_type = TYPE_FIELD_TYPE (type, 0);
+ if (TYPE_CODE (fld_type) == TYPE_CODE_ARRAY)
+ {
+ tgt_type = TYPE_TARGET_TYPE (fld_type);
+ if (TYPE_LENGTH (fld_type) >= 0 && TYPE_LENGTH (tgt_type) >= 0
+ && TYPE_LENGTH (fld_type) / TYPE_LENGTH (tgt_type) > 2)
+ return 1;
+ }
+ }
+ return 0;
+ }
+
+ /* The value is a union which contains at least one field which
+ * would be returned in registers according to these rules
+ * -> returned in register */
+ if (TYPE_CODE (type) == TYPE_CODE_UNION)
+ {
+ for (i = 0; i < TYPE_NFIELDS (type); ++i)
+ {
+ fld_type = TYPE_FIELD_TYPE (type, 0);
+ if (!v850_use_struct_convention (0, fld_type))
+ return 0;
+ }
+ }
+
+ return 1;
}
@@ -844,22 +929,22 @@ v850_push_arguments (int nargs, struct v
/* First, just for safety, make sure stack is aligned */
sp &= ~3;
+ /* 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.
+ I don't really know why, that's just the way it seems to work. */
+ stack_offset = 16;
+
/* Now make space on the stack for the args. */
for (argnum = 0; argnum < nargs; argnum++)
len += ((TYPE_LENGTH (VALUE_TYPE (args[argnum])) + 3) & ~3);
- sp -= len; /* possibly over-allocating, but it works... */
+ sp -= len + stack_offset; /* possibly over-allocating, but it works... */
/* (you might think we could allocate 16 bytes */
/* less, but the ABI seems to use it all! ) */
- argreg = E_ARG0_REGNUM;
+ argreg = E_ARG0_REGNUM;
/* the struct_return pointer occupies the first parameter-passing reg */
if (struct_return)
- write_register (argreg++, struct_addr);
-
- stack_offset = 16;
- /* 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.
- I don't really know why, that's just the way it seems to work. */
+ argreg++;
/* Now load as many as possible of the first arguments into
registers, and push the rest onto the stack. There are 16 bytes
@@ -870,8 +955,8 @@ v850_push_arguments (int nargs, struct v
char *val;
char valbuf[v850_register_raw_size (E_ARG0_REGNUM)];
- if (TYPE_CODE (VALUE_TYPE (*args)) == TYPE_CODE_STRUCT
- && TYPE_LENGTH (VALUE_TYPE (*args)) > 8)
+ if (!v850_type_is_scalar (VALUE_TYPE (*args))
+ && TYPE_LENGTH (VALUE_TYPE (*args)) > E_MAX_RETTYPE_SIZE_IN_REGS)
{
store_address (valbuf, 4, VALUE_ADDRESS (*args));
len = 4;
@@ -966,8 +1051,26 @@ v850_saved_pc_after_call (struct frame_i
static void
v850_extract_return_value (struct type *type, char *regbuf, char *valbuf)
{
- memcpy (valbuf, regbuf + v850_register_byte (E_V0_REGNUM),
- TYPE_LENGTH (type));
+ CORE_ADDR return_buffer;
+
+ if (!v850_use_struct_convention (0, type))
+ {
+ /* Scalar return values of <= 8 bytes are returned in
+ E_V0_REGNUM to E_V1_REGNUM. */
+ memcpy (valbuf,
+ ®buf[REGISTER_BYTE (E_V0_REGNUM)],
+ TYPE_LENGTH (type));
+ }
+ else
+ {
+ /* Aggregates and return values > 8 bytes are returned in memory,
+ pointed to by R6. */
+ return_buffer =
+ extract_address (regbuf + REGISTER_BYTE (E_V0_REGNUM),
+ REGISTER_RAW_SIZE (E_V0_REGNUM));
+
+ read_memory (return_buffer, valbuf, TYPE_LENGTH (type));
+ }
}
const static unsigned char *
@@ -988,8 +1091,16 @@ v850_extract_struct_value_address (char
static void
v850_store_return_value (struct type *type, char *valbuf)
{
- write_register_bytes(v850_register_byte (E_V0_REGNUM), valbuf,
- TYPE_LENGTH (type));
+ CORE_ADDR return_buffer;
+
+ if (!v850_use_struct_convention (0, type))
+ write_register_bytes (REGISTER_BYTE (E_V0_REGNUM), valbuf,
+ TYPE_LENGTH (type));
+ else
+ {
+ return_buffer = read_register (E_V0_REGNUM);
+ write_memory (return_buffer, valbuf, TYPE_LENGTH (type));
+ }
}
static void
@@ -1057,8 +1168,9 @@ v850_init_extra_frame_info (int fromleaf
}
static void
-v850_store_struct_return (CORE_ADDR a, CORE_ADDR b)
+v850_store_struct_return (CORE_ADDR addr, CORE_ADDR sp)
{
+ write_register (E_ARG0_REGNUM, addr);
}
static CORE_ADDR
--
Corinna Vinschen
Cygwin Developer
Red Hat, Inc.
mailto:vinschen@redhat.com
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