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b55e03665ddf2423df9baee0d3172892ba781c26
cpython-source-deps/src/aarch64/ffi.c
Richard Henderson b55e03665d aarch64: Treat void return as not passed in registers 
This lets us do less post-processing when there's no return value.
2014-11-12 09:28:44 +01:00

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/* Copyright (c) 2009, 2010, 2011, 2012 ARM Ltd.
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
``Software''), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <ffi.h>
#include <ffi_common.h>
#include "internal.h"
/* Force FFI_TYPE_LONGDOUBLE to be different than FFI_TYPE_DOUBLE;
all further uses in this file will refer to the 128-bit type. */
#if FFI_TYPE_DOUBLE != FFI_TYPE_LONGDOUBLE
# if FFI_TYPE_LONGDOUBLE != 4
# error FFI_TYPE_LONGDOUBLE out of date
# endif
#else
# undef FFI_TYPE_LONGDOUBLE
# define FFI_TYPE_LONGDOUBLE 4
#endif
union _d
{
UINT64 d;
UINT32 s[2];
};
struct _v
{
union _d d[2] __attribute__((aligned(16)));
};
struct call_context
{
struct _v v[N_V_ARG_REG];
UINT64 x[N_X_ARG_REG];
UINT64 x8;
};
#if defined (__clang__) && defined (__APPLE__)
extern void sys_icache_invalidate (void *start, size_t len);
#endif
static inline void
ffi_clear_cache (void *start, void *end)
{
#if defined (__clang__) && defined (__APPLE__)
sys_icache_invalidate (start, (char *)end - (char *)start);
#elif defined (__GNUC__)
__builtin___clear_cache (start, end);
#else
#error "Missing builtin to flush instruction cache"
#endif
}
static void *
get_x_addr (struct call_context *context, unsigned n)
{
return &context->x[n];
}
static void *
get_s_addr (struct call_context *context, unsigned n)
{
#if defined __AARCH64EB__
return &context->v[n].d[1].s[1];
#else
return &context->v[n].d[0].s[0];
#endif
}
static void *
get_d_addr (struct call_context *context, unsigned n)
{
#if defined __AARCH64EB__
return &context->v[n].d[1];
#else
return &context->v[n].d[0];
#endif
}
static void *
get_v_addr (struct call_context *context, unsigned n)
{
return &context->v[n];
}
/* Return the memory location at which a basic type would reside
were it to have been stored in register n. */
static void *
get_basic_type_addr (unsigned short type, struct call_context *context,
unsigned n)
{
switch (type)
{
case FFI_TYPE_FLOAT:
return get_s_addr (context, n);
case FFI_TYPE_DOUBLE:
return get_d_addr (context, n);
case FFI_TYPE_LONGDOUBLE:
return get_v_addr (context, n);
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_INT:
case FFI_TYPE_POINTER:
case FFI_TYPE_UINT64:
case FFI_TYPE_SINT64:
return get_x_addr (context, n);
case FFI_TYPE_VOID:
return NULL;
default:
FFI_ASSERT (0);
return NULL;
}
}
/* Return the alignment width for each of the basic types. */
static size_t
get_basic_type_alignment (unsigned short type)
{
switch (type)
{
case FFI_TYPE_FLOAT:
#if defined (__APPLE__)
return sizeof (UINT32);
#endif
case FFI_TYPE_DOUBLE:
return sizeof (UINT64);
case FFI_TYPE_LONGDOUBLE:
return sizeof (long double);
case FFI_TYPE_UINT8:
case FFI_TYPE_SINT8:
#if defined (__APPLE__)
return sizeof (UINT8);
#endif
case FFI_TYPE_UINT16:
case FFI_TYPE_SINT16:
#if defined (__APPLE__)
return sizeof (UINT16);
#endif
case FFI_TYPE_UINT32:
case FFI_TYPE_INT:
case FFI_TYPE_SINT32:
#if defined (__APPLE__)
return sizeof (UINT32);
#endif
case FFI_TYPE_POINTER:
case FFI_TYPE_UINT64:
case FFI_TYPE_SINT64:
return sizeof (UINT64);
default:
FFI_ASSERT (0);
return 0;
}
}
/* Return the size in bytes for each of the basic types. */
static size_t
get_basic_type_size (unsigned short type)
{
switch (type)
{
case FFI_TYPE_FLOAT:
return sizeof (UINT32);
case FFI_TYPE_DOUBLE:
return sizeof (UINT64);
case FFI_TYPE_LONGDOUBLE:
return sizeof (long double);
case FFI_TYPE_UINT8:
return sizeof (UINT8);
case FFI_TYPE_SINT8:
return sizeof (SINT8);
case FFI_TYPE_UINT16:
return sizeof (UINT16);
case FFI_TYPE_SINT16:
return sizeof (SINT16);
case FFI_TYPE_UINT32:
return sizeof (UINT32);
case FFI_TYPE_INT:
case FFI_TYPE_SINT32:
return sizeof (SINT32);
case FFI_TYPE_POINTER:
case FFI_TYPE_UINT64:
return sizeof (UINT64);
case FFI_TYPE_SINT64:
return sizeof (SINT64);
default:
FFI_ASSERT (0);
return 0;
}
}
extern void
ffi_call_SYSV (unsigned (*)(struct call_context *context, unsigned char *,
extended_cif *),
struct call_context *context,
extended_cif *,
size_t,
void (*fn)(void));
extern void
ffi_closure_SYSV (ffi_closure *);
/* Test for an FFI floating point representation. */
static unsigned
is_floating_type (unsigned short type)
{
return (type == FFI_TYPE_FLOAT || type == FFI_TYPE_DOUBLE
|| type == FFI_TYPE_LONGDOUBLE);
}
/* A subroutine of is_hfa. Given a structure type, return the type code
of the first non-structure element. Recurse for structure elements.
Return -1 if the structure is in fact empty, i.e. no nested elements. */
static int
is_hfa0 (const ffi_type *ty)
{
ffi_type **elements = ty->elements;
int i, ret = -1;
if (elements != NULL)
for (i = 0; elements[i]; ++i)
{
ret = elements[i]->type;
if (ret == FFI_TYPE_STRUCT)
{
ret = is_hfa0 (elements[i]);
if (ret < 0)
continue;
}
break;
}
return ret;
}
/* A subroutine of is_hfa. Given a structure type, return true if all
of the non-structure elements are the same as CANDIDATE. */
static int
is_hfa1 (const ffi_type *ty, int candidate)
{
ffi_type **elements = ty->elements;
int i;
if (elements != NULL)
for (i = 0; elements[i]; ++i)
{
int t = elements[i]->type;
if (t == FFI_TYPE_STRUCT)
{
if (!is_hfa1 (elements[i], candidate))
return 0;
}
else if (t != candidate)
return 0;
}
return 1;
}
/* Determine if TY is an homogenous floating point aggregate (HFA).
That is, a structure consisting of 1 to 4 members of all the same type,
where that type is a floating point scalar.
Returns non-zero iff TY is an HFA. The result is an encoded value where
bits 0-7 contain the type code, and bits 8-10 contain the element count. */
static int
is_hfa(const ffi_type *ty)
{
ffi_type **elements;
int candidate, i;
size_t size, ele_count;
/* Quickest tests first. */
if (ty->type != FFI_TYPE_STRUCT)
return 0;
/* No HFA types are smaller than 4 bytes, or larger than 64 bytes. */
size = ty->size;
if (size < 4 || size > 64)
return 0;
/* Find the type of the first non-structure member. */
elements = ty->elements;
candidate = elements[0]->type;
if (candidate == FFI_TYPE_STRUCT)
{
for (i = 0; ; ++i)
{
candidate = is_hfa0 (elements[i]);
if (candidate >= 0)
break;
}
}
/* If the first member is not a floating point type, it's not an HFA.
Also quickly re-check the size of the structure. */
switch (candidate)
{
case FFI_TYPE_FLOAT:
ele_count = size / sizeof(float);
if (size != ele_count * sizeof(float))
return 0;
break;
case FFI_TYPE_DOUBLE:
ele_count = size / sizeof(double);
if (size != ele_count * sizeof(double))
return 0;
break;
case FFI_TYPE_LONGDOUBLE:
ele_count = size / sizeof(long double);
if (size != ele_count * sizeof(long double))
return 0;
break;
default:
return 0;
}
if (ele_count > 4)
return 0;
/* Finally, make sure that all scalar elements are the same type. */
for (i = 0; elements[i]; ++i)
{
if (elements[i]->type == FFI_TYPE_STRUCT)
{
if (!is_hfa1 (elements[i], candidate))
return 0;
}
else if (elements[i]->type != candidate)
return 0;
}
/* All tests succeeded. Encode the result. */
return (ele_count << 8) | candidate;
}
/* Test if an ffi_type is a candidate for passing in a register.
This test does not check that sufficient registers of the
appropriate class are actually available, merely that IFF
sufficient registers are available then the argument will be passed
in register(s).
Note that an ffi_type that is deemed to be a register candidate
will always be returned in registers.
Returns 1 if a register candidate else 0. */
static int
is_register_candidate (ffi_type *ty)
{
switch (ty->type)
{
case FFI_TYPE_VOID:
return 0;
case FFI_TYPE_FLOAT:
case FFI_TYPE_DOUBLE:
case FFI_TYPE_LONGDOUBLE:
case FFI_TYPE_UINT8:
case FFI_TYPE_UINT16:
case FFI_TYPE_UINT32:
case FFI_TYPE_UINT64:
case FFI_TYPE_POINTER:
case FFI_TYPE_SINT8:
case FFI_TYPE_SINT16:
case FFI_TYPE_SINT32:
case FFI_TYPE_INT:
case FFI_TYPE_SINT64:
return 1;
case FFI_TYPE_STRUCT:
if (is_hfa (ty))
{
return 1;
}
else if (ty->size > 16)
{
/* Too large. Will be replaced with a pointer to memory. The
pointer MAY be passed in a register, but the value will
not. This test specifically fails since the argument will
never be passed by value in registers. */
return 0;
}
else
{
/* Might be passed in registers depending on the number of
registers required. */
return (ty->size + 7) / 8 < N_X_ARG_REG;
}
break;
default:
FFI_ASSERT (0);
break;
}
return 0;
}
/* Test if an ffi_type argument or result is a candidate for a vector
register. */
static int
is_v_register_candidate (ffi_type *ty)
{
return is_floating_type (ty->type)
|| (ty->type == FFI_TYPE_STRUCT && is_hfa (ty));
}
/* Representation of the procedure call argument marshalling
state.
The terse state variable names match the names used in the AARCH64
PCS. */
struct arg_state
{
unsigned ngrn; /* Next general-purpose register number. */
unsigned nsrn; /* Next vector register number. */
size_t nsaa; /* Next stack offset. */
#if defined (__APPLE__)
unsigned allocating_variadic;
#endif
};
/* Initialize a procedure call argument marshalling state. */
static void
arg_init (struct arg_state *state, size_t call_frame_size)
{
state->ngrn = 0;
state->nsrn = 0;
state->nsaa = 0;
#if defined (__APPLE__)
state->allocating_variadic = 0;
#endif
}
/* Return the number of available consecutive core argument
registers. */
static unsigned
available_x (struct arg_state *state)
{
return N_X_ARG_REG - state->ngrn;
}
/* Return the number of available consecutive vector argument
registers. */
static unsigned
available_v (struct arg_state *state)
{
return N_V_ARG_REG - state->nsrn;
}
static void *
allocate_to_x (struct call_context *context, struct arg_state *state)
{
FFI_ASSERT (state->ngrn < N_X_ARG_REG);
return get_x_addr (context, (state->ngrn)++);
}
static void *
allocate_to_s (struct call_context *context, struct arg_state *state)
{
FFI_ASSERT (state->nsrn < N_V_ARG_REG);
return get_s_addr (context, (state->nsrn)++);
}
static void *
allocate_to_d (struct call_context *context, struct arg_state *state)
{
FFI_ASSERT (state->nsrn < N_V_ARG_REG);
return get_d_addr (context, (state->nsrn)++);
}
static void *
allocate_to_v (struct call_context *context, struct arg_state *state)
{
FFI_ASSERT (state->nsrn < N_V_ARG_REG);
return get_v_addr (context, (state->nsrn)++);
}
/* Allocate an aligned slot on the stack and return a pointer to it. */
static void *
allocate_to_stack (struct arg_state *state, void *stack, size_t alignment,
size_t size)
{
void *allocation;
/* Round up the NSAA to the larger of 8 or the natural
alignment of the argument's type. */
state->nsaa = ALIGN (state->nsaa, alignment);
state->nsaa = ALIGN (state->nsaa, alignment);
#if defined (__APPLE__)
if (state->allocating_variadic)
state->nsaa = ALIGN (state->nsaa, 8);
#else
state->nsaa = ALIGN (state->nsaa, 8);
#endif
allocation = stack + state->nsaa;
state->nsaa += size;
return allocation;
}
static void
copy_basic_type (void *dest, void *source, unsigned short type)
{
/* This is necessary to ensure that basic types are copied
sign extended to 64-bits as libffi expects. */
switch (type)
{
case FFI_TYPE_FLOAT:
*(float *) dest = *(float *) source;
break;
case FFI_TYPE_DOUBLE:
*(double *) dest = *(double *) source;
break;
case FFI_TYPE_LONGDOUBLE:
*(long double *) dest = *(long double *) source;
break;
case FFI_TYPE_UINT8:
*(ffi_arg *) dest = *(UINT8 *) source;
break;
case FFI_TYPE_SINT8:
*(ffi_sarg *) dest = *(SINT8 *) source;
break;
case FFI_TYPE_UINT16:
*(ffi_arg *) dest = *(UINT16 *) source;
break;
case FFI_TYPE_SINT16:
*(ffi_sarg *) dest = *(SINT16 *) source;
break;
case FFI_TYPE_UINT32:
*(ffi_arg *) dest = *(UINT32 *) source;
break;
case FFI_TYPE_INT:
case FFI_TYPE_SINT32:
*(ffi_sarg *) dest = *(SINT32 *) source;
break;
case FFI_TYPE_POINTER:
case FFI_TYPE_UINT64:
*(ffi_arg *) dest = *(UINT64 *) source;
break;
case FFI_TYPE_SINT64:
*(ffi_sarg *) dest = *(SINT64 *) source;
break;
case FFI_TYPE_VOID:
break;
default:
FFI_ASSERT (0);
}
}
static void
copy_hfa_to_reg_or_stack (void *memory,
ffi_type *ty,
struct call_context *context,
unsigned char *stack,
struct arg_state *state)
{
int h = is_hfa (ty);
int type = h & 0xff;
unsigned elems = h >> 8;
if (available_v (state) < elems)
{
/* There are insufficient V registers. Further V register allocations
are prevented, the NSAA is adjusted (by allocate_to_stack ())
and the argument is copied to memory at the adjusted NSAA. */
state->nsrn = N_V_ARG_REG;
memcpy (allocate_to_stack (state, stack, ty->alignment, ty->size),
memory,
ty->size);
}
else
{
int i;
for (i = 0; i < elems; i++)
{
void *reg = allocate_to_v (context, state);
copy_basic_type (reg, memory, type);
memory += get_basic_type_size (type);
}
}
}
/* Either allocate an appropriate register for the argument type, or if
none are available, allocate a stack slot and return a pointer
to the allocated space. */
static void *
allocate_to_register_or_stack (struct call_context *context,
unsigned char *stack,
struct arg_state *state,
unsigned short type)
{
size_t alignment = get_basic_type_alignment (type);
size_t size = alignment;
switch (type)
{
case FFI_TYPE_FLOAT:
/* This is the only case for which the allocated stack size
should not match the alignment of the type. */
size = sizeof (UINT32);
/* Fall through. */
case FFI_TYPE_DOUBLE:
if (state->nsrn < N_V_ARG_REG)
return allocate_to_d (context, state);
state->nsrn = N_V_ARG_REG;
break;
case FFI_TYPE_LONGDOUBLE:
if (state->nsrn < N_V_ARG_REG)
return allocate_to_v (context, state);
state->nsrn = N_V_ARG_REG;
break;
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_INT:
case FFI_TYPE_POINTER:
case FFI_TYPE_UINT64:
case FFI_TYPE_SINT64:
if (state->ngrn < N_X_ARG_REG)
return allocate_to_x (context, state);
state->ngrn = N_X_ARG_REG;
break;
default:
FFI_ASSERT (0);
}
return allocate_to_stack (state, stack, alignment, size);
}
/* Copy a value to an appropriate register, or if none are
available, to the stack. */
static void
copy_to_register_or_stack (struct call_context *context,
unsigned char *stack,
struct arg_state *state,
void *value,
unsigned short type)
{
copy_basic_type (
allocate_to_register_or_stack (context, stack, state, type),
value,
type);
}
/* Marshall the arguments from FFI representation to procedure call
context and stack. */
static unsigned
aarch64_prep_args (struct call_context *context, unsigned char *stack,
extended_cif *ecif)
{
int i;
struct arg_state state;
arg_init (&state, ALIGN(ecif->cif->bytes, 16));
for (i = 0; i < ecif->cif->nargs; i++)
{
ffi_type *ty = ecif->cif->arg_types[i];
switch (ty->type)
{
case FFI_TYPE_VOID:
FFI_ASSERT (0);
break;
/* If the argument is a basic type the argument is allocated to an
appropriate register, or if none are available, to the stack. */
case FFI_TYPE_FLOAT:
case FFI_TYPE_DOUBLE:
case FFI_TYPE_LONGDOUBLE:
case FFI_TYPE_UINT8:
case FFI_TYPE_SINT8:
case FFI_TYPE_UINT16:
case FFI_TYPE_SINT16:
case FFI_TYPE_UINT32:
case FFI_TYPE_INT:
case FFI_TYPE_SINT32:
case FFI_TYPE_POINTER:
case FFI_TYPE_UINT64:
case FFI_TYPE_SINT64:
copy_to_register_or_stack (context, stack, &state,
ecif->avalue[i], ty->type);
break;
case FFI_TYPE_STRUCT:
if (is_hfa (ty))
{
copy_hfa_to_reg_or_stack (ecif->avalue[i], ty, context,
stack, &state);
}
else if (ty->size > 16)
{
/* If the argument is a composite type that is larger than 16
bytes, then the argument has been copied to memory, and
the argument is replaced by a pointer to the copy. */
copy_to_register_or_stack (context, stack, &state,
&(ecif->avalue[i]), FFI_TYPE_POINTER);
}
else if (available_x (&state) >= (ty->size + 7) / 8)
{
/* If the argument is a composite type and the size in
double-words is not more than the number of available
X registers, then the argument is copied into consecutive
X registers. */
int j;
for (j = 0; j < (ty->size + 7) / 8; j++)
{
memcpy (allocate_to_x (context, &state),
&(((UINT64 *) ecif->avalue[i])[j]),
sizeof (UINT64));
}
}
else
{
/* Otherwise, there are insufficient X registers. Further X
register allocations are prevented, the NSAA is adjusted
(by allocate_to_stack ()) and the argument is copied to
memory at the adjusted NSAA. */
state.ngrn = N_X_ARG_REG;
memcpy (allocate_to_stack (&state, stack, ty->alignment,
ty->size), ecif->avalue + i, ty->size);
}
break;
default:
FFI_ASSERT (0);
break;
}
#if defined (__APPLE__)
if (i + 1 == ecif->cif->aarch64_nfixedargs)
{
state.ngrn = N_X_ARG_REG;
state.nsrn = N_V_ARG_REG;
state.allocating_variadic = 1;
}
#endif
}
return ecif->cif->aarch64_flags;
}
ffi_status
ffi_prep_cif_machdep (ffi_cif *cif)
{
/* Round the stack up to a multiple of the stack alignment requirement. */
cif->bytes = ALIGN(cif->bytes, 16);
/* Initialize our flags. We are interested if this CIF will touch a
vector register, if so we will enable context save and load to
those registers, otherwise not. This is intended to be friendly
to lazy float context switching in the kernel. */
cif->aarch64_flags = 0;
if (is_v_register_candidate (cif->rtype))
{
cif->aarch64_flags |= AARCH64_FLAG_ARG_V;
}
else
{
int i;
for (i = 0; i < cif->nargs; i++)
if (is_v_register_candidate (cif->arg_types[i]))
{
cif->aarch64_flags |= AARCH64_FLAG_ARG_V;
break;
}
}
#if defined (__APPLE__)
cif->aarch64_nfixedargs = 0;
#endif
return FFI_OK;
}
#if defined (__APPLE__)
/* Perform Apple-specific cif processing for variadic calls */
ffi_status ffi_prep_cif_machdep_var(ffi_cif *cif,
unsigned int nfixedargs,
unsigned int ntotalargs)
{
ffi_status status;
status = ffi_prep_cif_machdep (cif);
cif->aarch64_nfixedargs = nfixedargs;
return status;
}
#endif
/* Call a function with the provided arguments and capture the return
value. */
void
ffi_call (ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
{
extended_cif ecif;
int h;
ecif.cif = cif;
ecif.avalue = avalue;
ecif.rvalue = rvalue;
switch (cif->abi)
{
case FFI_SYSV:
{
struct call_context context;
size_t stack_bytes;
/* Figure out the total amount of stack space we need, the
above call frame space needs to be 16 bytes aligned to
ensure correct alignment of the first object inserted in
that space hence the ALIGN applied to cif->bytes.*/
stack_bytes = ALIGN(cif->bytes, 16);
memset (&context, 0, sizeof (context));
if (is_register_candidate (cif->rtype))
{
ffi_call_SYSV (aarch64_prep_args, &context, &ecif, stack_bytes, fn);
switch (cif->rtype->type)
{
case FFI_TYPE_VOID:
case FFI_TYPE_FLOAT:
case FFI_TYPE_DOUBLE:
case FFI_TYPE_LONGDOUBLE:
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_POINTER:
case FFI_TYPE_UINT64:
case FFI_TYPE_INT:
case FFI_TYPE_SINT64:
{
void *addr = get_basic_type_addr (cif->rtype->type,
&context, 0);
copy_basic_type (rvalue, addr, cif->rtype->type);
break;
}
case FFI_TYPE_STRUCT:
h = is_hfa (cif->rtype);
if (h)
{
int j;
int type = h & 0xff;
int elems = h >> 8;
for (j = 0; j < elems; j++)
{
void *reg = get_basic_type_addr (type, &context, j);
copy_basic_type (rvalue, reg, type);
rvalue += get_basic_type_size (type);
}
}
else if ((cif->rtype->size + 7) / 8 < N_X_ARG_REG)
{
size_t size = ALIGN (cif->rtype->size, sizeof (UINT64));
memcpy (rvalue, get_x_addr (&context, 0), size);
}
else
{
FFI_ASSERT (0);
}
break;
default:
FFI_ASSERT (0);
break;
}
}
else
{
context.x8 = (uintptr_t)rvalue;
ffi_call_SYSV (aarch64_prep_args, &context, &ecif,
stack_bytes, fn);
}
break;
}
default:
FFI_ASSERT (0);
break;
}
}
static unsigned char trampoline [] =
{ 0x70, 0x00, 0x00, 0x58, /* ldr x16, 1f */
0x91, 0x00, 0x00, 0x10, /* adr x17, 2f */
0x00, 0x02, 0x1f, 0xd6 /* br x16 */
};
/* Build a trampoline. */
#define FFI_INIT_TRAMPOLINE(TRAMP,FUN,CTX,FLAGS) \
({unsigned char *__tramp = (unsigned char*)(TRAMP); \
UINT64 __fun = (UINT64)(FUN); \
UINT64 __ctx = (UINT64)(CTX); \
UINT64 __flags = (UINT64)(FLAGS); \
memcpy (__tramp, trampoline, sizeof (trampoline)); \
memcpy (__tramp + 12, &__fun, sizeof (__fun)); \
memcpy (__tramp + 20, &__ctx, sizeof (__ctx)); \
memcpy (__tramp + 28, &__flags, sizeof (__flags)); \
ffi_clear_cache(__tramp, __tramp + FFI_TRAMPOLINE_SIZE); \
})
ffi_status
ffi_prep_closure_loc (ffi_closure* closure,
ffi_cif* cif,
void (*fun)(ffi_cif*,void*,void**,void*),
void *user_data,
void *codeloc)
{
if (cif->abi != FFI_SYSV)
return FFI_BAD_ABI;
FFI_INIT_TRAMPOLINE (&closure->tramp[0], &ffi_closure_SYSV, codeloc,
cif->aarch64_flags);
closure->cif = cif;
closure->user_data = user_data;
closure->fun = fun;
return FFI_OK;
}
/* Primary handler to setup and invoke a function within a closure.
A closure when invoked enters via the assembler wrapper
ffi_closure_SYSV(). The wrapper allocates a call context on the
stack, saves the interesting registers (from the perspective of
the calling convention) into the context then passes control to
ffi_closure_SYSV_inner() passing the saved context and a pointer to
the stack at the point ffi_closure_SYSV() was invoked.
On the return path the assembler wrapper will reload call context
registers.
ffi_closure_SYSV_inner() marshalls the call context into ffi value
descriptors, invokes the wrapped function, then marshalls the return
value back into the call context. */
void FFI_HIDDEN
ffi_closure_SYSV_inner (ffi_closure *closure, struct call_context *context,
void *stack)
{
ffi_cif *cif = closure->cif;
void **avalue = (void**) alloca (cif->nargs * sizeof (void*));
void *rvalue = NULL;
int i, h;
struct arg_state state;
arg_init (&state, ALIGN(cif->bytes, 16));
for (i = 0; i < cif->nargs; i++)
{
ffi_type *ty = cif->arg_types[i];
switch (ty->type)
{
case FFI_TYPE_VOID:
FFI_ASSERT (0);
break;
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_INT:
case FFI_TYPE_POINTER:
case FFI_TYPE_UINT64:
case FFI_TYPE_SINT64:
case FFI_TYPE_FLOAT:
case FFI_TYPE_DOUBLE:
case FFI_TYPE_LONGDOUBLE:
avalue[i] = allocate_to_register_or_stack (context, stack,
&state, ty->type);
break;
case FFI_TYPE_STRUCT:
h = is_hfa (ty);
if (h)
{
unsigned n = h >> 8;
if (available_v (&state) < n)
{
state.nsrn = N_V_ARG_REG;
avalue[i] = allocate_to_stack (&state, stack, ty->alignment,
ty->size);
}
else
{
switch (h & 0xff)
{
case FFI_TYPE_FLOAT:
{
/* Eeek! We need a pointer to the structure,
however the homogeneous float elements are
being passed in individual S registers,
therefore the structure is not represented as
a contiguous sequence of bytes in our saved
register context. We need to fake up a copy
of the structure laid out in memory
correctly. The fake can be tossed once the
closure function has returned hence alloca()
is sufficient. */
unsigned j;
UINT32 *p = avalue[i] = alloca (ty->size);
for (j = 0; j < n; j++)
memcpy (&p[j],
allocate_to_s (context, &state),
sizeof (*p));
break;
}
case FFI_TYPE_DOUBLE:
{
/* Eeek! We need a pointer to the structure,
however the homogeneous float elements are
being passed in individual S registers,
therefore the structure is not represented as
a contiguous sequence of bytes in our saved
register context. We need to fake up a copy
of the structure laid out in memory
correctly. The fake can be tossed once the
closure function has returned hence alloca()
is sufficient. */
unsigned j;
UINT64 *p = avalue[i] = alloca (ty->size);
for (j = 0; j < n; j++)
memcpy (&p[j],
allocate_to_d (context, &state),
sizeof (*p));
break;
}
case FFI_TYPE_LONGDOUBLE:
memcpy (&avalue[i],
allocate_to_v (context, &state),
sizeof (*avalue));
break;
default:
FFI_ASSERT (0);
break;
}
}
}
else if (ty->size > 16)
{
/* Replace Composite type of size greater than 16 with a
pointer. */
memcpy (&avalue[i],
allocate_to_register_or_stack (context, stack,
&state, FFI_TYPE_POINTER),
sizeof (avalue[i]));
}
else if (available_x (&state) >= (ty->size + 7) / 8)
{
avalue[i] = get_x_addr (context, state.ngrn);
state.ngrn += (ty->size + 7) / 8;
}
else
{
state.ngrn = N_X_ARG_REG;
avalue[i] = allocate_to_stack (&state, stack, ty->alignment,
ty->size);
}
break;
default:
FFI_ASSERT (0);
break;
}
}
/* Figure out where the return value will be passed, either in
registers or in a memory block allocated by the caller and passed
in x8. */
if (is_register_candidate (cif->rtype))
{
/* Register candidates are *always* returned in registers. */
/* Allocate a scratchpad for the return value, we will let the
callee scrible the result into the scratch pad then move the
contents into the appropriate return value location for the
call convention. */
rvalue = alloca (cif->rtype->size);
(closure->fun) (cif, rvalue, avalue, closure->user_data);
/* Copy the return value into the call context so that it is returned
as expected to our caller. */
switch (cif->rtype->type)
{
case FFI_TYPE_VOID:
break;
case FFI_TYPE_UINT8:
case FFI_TYPE_UINT16:
case FFI_TYPE_UINT32:
case FFI_TYPE_POINTER:
case FFI_TYPE_UINT64:
case FFI_TYPE_SINT8:
case FFI_TYPE_SINT16:
case FFI_TYPE_INT:
case FFI_TYPE_SINT32:
case FFI_TYPE_SINT64:
case FFI_TYPE_FLOAT:
case FFI_TYPE_DOUBLE:
case FFI_TYPE_LONGDOUBLE:
{
void *addr = get_basic_type_addr (cif->rtype->type, context, 0);
copy_basic_type (addr, rvalue, cif->rtype->type);
break;
}
case FFI_TYPE_STRUCT:
h = is_hfa (cif->rtype);
if (h)
{
int j;
int type = h & 0xff;
int elems = h >> 8;
for (j = 0; j < elems; j++)
{
void *reg = get_basic_type_addr (type, context, j);
copy_basic_type (reg, rvalue, type);
rvalue += get_basic_type_size (type);
}
}
else if ((cif->rtype->size + 7) / 8 < N_X_ARG_REG)
{
size_t size = ALIGN (cif->rtype->size, sizeof (UINT64)) ;
memcpy (get_x_addr (context, 0), rvalue, size);
}
else
{
FFI_ASSERT (0);
}
break;
default:
FFI_ASSERT (0);
break;
}
}
else
{
rvalue = (void *)(uintptr_t)context->x8;
(closure->fun) (cif, rvalue, avalue, closure->user_data);
}
}
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