unsigned int DisjointSets<T, hasher>::merge_items(
const T& item1,
const T& item2
) {
const unsigned int c1 = item_class(item1) ;
if(c1 == NO_CLASS) return NO_CLASS ;
const unsigned int c2 = item_class(item2) ;
if(c2 == NO_CLASS) return NO_CLASS ;
return merge_classes(c1, c2) ;
}
/* Classify the argument of type TYPE and mode MODE.
CLASSES will be filled by the register class used to pass each word
of the operand. The number of words is returned. In case the parameter
should be passed in memory, 0 is returned. As a special case for zero
sized containers, classes[0] will be NO_CLASS and 1 is returned.
See the x86-64 PS ABI for details.
*/
static int
classify_argument (ffi_type *type, enum x86_64_reg_class classes[],
size_t byte_offset)
{
switch (type->type)
{
case FFI_TYPE_UINT8:
case FFI_TYPE_SINT8:
case FFI_TYPE_UINT16:
case FFI_TYPE_SINT16:
case FFI_TYPE_UINT32:
case FFI_TYPE_SINT32:
case FFI_TYPE_UINT64:
case FFI_TYPE_SINT64:
case FFI_TYPE_POINTER:
{
int size = byte_offset + type->size;
if (size <= 4)
{
classes[0] = X86_64_INTEGERSI_CLASS;
return 1;
}
else if (size <= 8)
{
classes[0] = X86_64_INTEGER_CLASS;
return 1;
}
else if (size <= 12)
{
classes[0] = X86_64_INTEGER_CLASS;
classes[1] = X86_64_INTEGERSI_CLASS;
return 2;
}
else if (size <= 16)
{
classes[0] = classes[1] = X86_64_INTEGERSI_CLASS;
return 2;
}
else
FFI_ASSERT (0);
}
case FFI_TYPE_FLOAT:
if (!(byte_offset % 8))
classes[0] = X86_64_SSESF_CLASS;
else
classes[0] = X86_64_SSE_CLASS;
return 1;
case FFI_TYPE_DOUBLE:
classes[0] = X86_64_SSEDF_CLASS;
return 1;
case FFI_TYPE_LONGDOUBLE:
classes[0] = X86_64_X87_CLASS;
classes[1] = X86_64_X87UP_CLASS;
return 2;
case FFI_TYPE_STRUCT:
{
const int UNITS_PER_WORD = 8;
int words = (type->size + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
ffi_type **ptr;
int i;
enum x86_64_reg_class subclasses[MAX_CLASSES];
/* If the struct is larger than 32 bytes, pass it on the stack. */
if (type->size > 32)
return 0;
for (i = 0; i < words; i++)
classes[i] = X86_64_NO_CLASS;
/* Zero sized arrays or structures are NO_CLASS. We return 0 to
signalize memory class, so handle it as special case. */
if (!words)
{
classes[0] = X86_64_NO_CLASS;
return 1;
}
/* Merge the fields of structure. */
for (ptr = type->elements; *ptr != NULL; ptr++)
{
int num;
byte_offset = ALIGN (byte_offset, (*ptr)->alignment);
num = classify_argument (*ptr, subclasses, byte_offset % 8);
if (num == 0)
return 0;
for (i = 0; i < num; i++)
{
int pos = byte_offset / 8;
classes[i + pos] =
merge_classes (subclasses[i], classes[i + pos]);
}
byte_offset += (*ptr)->size;
}
if (words > 2)
{
/* When size > 16 bytes, if the first one isn't
X86_64_SSE_CLASS or any other ones aren't
X86_64_SSEUP_CLASS, everything should be passed in
memory. */
if (classes[0] != X86_64_SSE_CLASS)
return 0;
for (i = 1; i < words; i++)
if (classes[i] != X86_64_SSEUP_CLASS)
return 0;
}
/* Final merger cleanup. */
for (i = 0; i < words; i++)
{
/* If one class is MEMORY, everything should be passed in
memory. */
if (classes[i] == X86_64_MEMORY_CLASS)
return 0;
/* The X86_64_SSEUP_CLASS should be always preceded by
X86_64_SSE_CLASS or X86_64_SSEUP_CLASS. */
if (classes[i] == X86_64_SSEUP_CLASS
&& classes[i - 1] != X86_64_SSE_CLASS
&& classes[i - 1] != X86_64_SSEUP_CLASS)
{
/* The first one should never be X86_64_SSEUP_CLASS. */
FFI_ASSERT (i != 0);
classes[i] = X86_64_SSE_CLASS;
}
/* If X86_64_X87UP_CLASS isn't preceded by X86_64_X87_CLASS,
everything should be passed in memory. */
if (classes[i] == X86_64_X87UP_CLASS
&& (classes[i - 1] != X86_64_X87_CLASS))
{
/* The first one should never be X86_64_X87UP_CLASS. */
FFI_ASSERT (i != 0);
return 0;
}
}
return words;
}
default:
FFI_ASSERT(0);
}
return 0; /* Never reached. */
}
/* Classify the argument of type TYPE and mode MODE.
CLASSES will be filled by the register class used to pass each word
of the operand. The number of words is returned. In case the parameter
should be passed in memory, 0 is returned. As a special case for zero
sized containers, classes[0] will be NO_CLASS and 1 is returned.
See the x86-64 PS ABI for details.
*/
static int
classify_argument (ffi_type *type, enum x86_64_reg_class classes[],
int *byte_offset)
{
/* First, align to the right place. */
*byte_offset = ALIGN(*byte_offset, type->alignment);
switch (type->type)
{
case FFI_TYPE_UINT8:
case FFI_TYPE_SINT8:
case FFI_TYPE_UINT16:
case FFI_TYPE_SINT16:
case FFI_TYPE_UINT32:
case FFI_TYPE_SINT32:
case FFI_TYPE_UINT64:
case FFI_TYPE_SINT64:
case FFI_TYPE_POINTER:
if (((*byte_offset) % 8 + type->size) <= 4)
classes[0] = X86_64_INTEGERSI_CLASS;
else
classes[0] = X86_64_INTEGER_CLASS;
return 1;
case FFI_TYPE_FLOAT:
if (((*byte_offset) % 8) == 0)
classes[0] = X86_64_SSESF_CLASS;
else
classes[0] = X86_64_SSE_CLASS;
return 1;
case FFI_TYPE_DOUBLE:
classes[0] = X86_64_SSEDF_CLASS;
return 1;
case FFI_TYPE_LONGDOUBLE:
classes[0] = X86_64_X87_CLASS;
classes[1] = X86_64_X87UP_CLASS;
return 2;
case FFI_TYPE_STRUCT:
{
const int UNITS_PER_WORD = 8;
int words = (type->size + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
ffi_type **ptr;
int i;
enum x86_64_reg_class subclasses[MAX_CLASSES];
/* If the struct is larger than 16 bytes, pass it on the stack. */
if (type->size > 16)
return 0;
for (i = 0; i < words; i++)
classes[i] = X86_64_NO_CLASS;
/* Merge the fields of structure. */
for (ptr=type->elements; (*ptr)!=NULL; ptr++)
{
int num;
num = classify_argument (*ptr, subclasses, byte_offset);
if (num == 0)
return 0;
for (i = 0; i < num; i++)
{
int pos = *byte_offset / 8;
classes[i + pos] =
merge_classes (subclasses[i], classes[i + pos]);
}
if ((*ptr)->type != FFI_TYPE_STRUCT)
*byte_offset += (*ptr)->size;
}
/* Final merger cleanup. */
for (i = 0; i < words; i++)
{
/* If one class is MEMORY, everything should be passed in
memory. */
if (classes[i] == X86_64_MEMORY_CLASS)
return 0;
/* The X86_64_SSEUP_CLASS should be always preceded by
X86_64_SSE_CLASS. */
if (classes[i] == X86_64_SSEUP_CLASS
&& (i == 0 || classes[i - 1] != X86_64_SSE_CLASS))
classes[i] = X86_64_SSE_CLASS;
/* X86_64_X87UP_CLASS should be preceded by X86_64_X87_CLASS. */
if (classes[i] == X86_64_X87UP_CLASS
&& (i == 0 || classes[i - 1] != X86_64_X87_CLASS))
classes[i] = X86_64_SSE_CLASS;
}
return words;
}
default:
FFI_ASSERT(0);
}
return 0; /* Never reached. */
}
