/*
* @APPLE_LICENSE_HEADER_START@
*
* Copyright (c) 1999-2007 Apple Computer, Inc. All Rights Reserved.
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
/********************************************************************
*
* objc-msg-arm.s - ARM code to support objc messaging
*
********************************************************************/
#ifdef __arm__
#include <arm/arch.h>
#ifndef _ARM_ARCH_7
# error requires armv7
#endif
// Set FP=1 on architectures that pass parameters in floating-point registers
#if __ARM_ARCH_7K__
# define FP 1
#else
# define FP 0
#endif
#if FP
# if !__ARM_NEON__
# error sorry
# endif
# define FP_RETURN_ZERO \
vmov.i32 q0, #0 vmov.i32 q2, #0
# define FP_SAVE \
vpush {q0-q3}
# define FP_RESTORE \
vpop {q0-q3}
#else
# define FP_RETURN_ZERO
# define FP_SAVE
# define FP_RESTORE
#endif
// Define SUPPORT_INDEXED_ISA for targets which store the class in the ISA as
// an index in to a class table.
// Note, keep this in sync with objc-config.h.
// FIXME: Remove this duplication. We should get this from objc-config.h.
#if __ARM_ARCH_7K__ >= 2
# define SUPPORT_INDEXED_ISA 1
#else
# define SUPPORT_INDEXED_ISA 0
#endif
// Note, keep these in sync with objc-private.h
#define ISA_INDEX_IS_NPI 1
#define ISA_INDEX_MASK 0x0001FFFC
#define ISA_INDEX_SHIFT 2
#define ISA_INDEX_BITS 15
#define ISA_INDEX_COUNT (1 << ISA_INDEX_BITS)
#define ISA_INDEX_MAGIC_MASK 0x001E0001
#define ISA_INDEX_MAGIC_VALUE 0x001C0001
.syntax unified
#define MI_EXTERN(var) \
.non_lazy_symbol_pointer .indirect_symbol var
#define MI_GET_EXTERN(reg,var) \
movw reg, :lower16:(L##var##$$non_lazy_ptr-7f-4) 7: add reg, pc
#define MI_GET_ADDRESS(reg,var) \
movw reg, :lower16:(var-7f-4) 7: add reg, pc
.data
#if SUPPORT_INDEXED_ISA
.align 2
.globl _objc_indexed_classes
_objc_indexed_classes:
.fill ISA_INDEX_COUNT, 4, 0
#endif
// _objc_entryPoints and _objc_exitPoints are used by method dispatch
// caching code to figure out whether any threads are actively
// in the cache for dispatching. The labels surround the asm code
// that do cache lookups. The tables are zero-terminated.
.align 2
.private_extern _objc_entryPoints
_objc_entryPoints:
.long _cache_getImp
.long _objc_msgSend
.long _objc_msgSend_stret
.long _objc_msgSendSuper
.long _objc_msgSendSuper_stret
.long _objc_msgSendSuper2
.long _objc_msgSendSuper2_stret
.long _objc_msgLookup
.long _objc_msgLookup_stret
.long _objc_msgLookupSuper2
.long _objc_msgLookupSuper2_stret
.long 0
.private_extern _objc_exitPoints
_objc_exitPoints:
.long LExit_cache_getImp
.long LExit_objc_msgSend
.long LExit_objc_msgSend_stret
.long LExit_objc_msgSendSuper
.long LExit_objc_msgSendSuper_stret
.long LExit_objc_msgSendSuper2
.long LExit_objc_msgSendSuper2_stret
.long LExit_objc_msgLookup
.long LExit_objc_msgLookup_stret
.long LExit_objc_msgLookupSuper2
.long LExit_objc_msgLookupSuper2_stret
.long 0
/********************************************************************
* List every exit insn from every messenger for debugger use.
* Format:
* (
* 1 word instruction's address
* 1 word type (ENTER or FAST_EXIT or SLOW_EXIT or NIL_EXIT)
* )
* 1 word zero
*
* ENTER is the start of a dispatcher
* FAST_EXIT is method dispatch
* SLOW_EXIT is uncached method lookup
* NIL_EXIT is returning zero from a message sent to nil
* These must match objc-gdb.h.
********************************************************************/
#define ENTER 1
#define FAST_EXIT 2
#define SLOW_EXIT 3
#define NIL_EXIT 4
.section __DATA,__objc_msg_break
.globl _gdb_objc_messenger_breakpoints
_gdb_objc_messenger_breakpoints:
// contents populated by the macros below
.macro MESSENGER_START
7:
.section __DATA,__objc_msg_break
.long 7b
.long ENTER
.text
.endmacro
.macro MESSENGER_END_FAST
7:
.section __DATA,__objc_msg_break
.long 7b
.long FAST_EXIT
.text
.endmacro
.macro MESSENGER_END_SLOW
7:
.section __DATA,__objc_msg_break
.long 7b
.long SLOW_EXIT
.text
.endmacro
.macro MESSENGER_END_NIL
7:
.section __DATA,__objc_msg_break
.long 7b
.long NIL_EXIT
.text
.endmacro
/********************************************************************
* Names for relative labels
* DO NOT USE THESE LABELS ELSEWHERE
* Reserved labels: 6: 7: 8: 9:
********************************************************************/
// 6: used by CacheLookup
// 7: used by MI_GET_ADDRESS etc and MESSENGER_START etc
// 8: used by CacheLookup
#define LNilReceiver 9
#define LNilReceiver_f 9f
#define LNilReceiver_b 9b
/********************************************************************
* Macro parameters
********************************************************************/
#define NORMAL 0
#define STRET 1
/********************************************************************
*
* Structure definitions.
*
********************************************************************/
/* objc_super parameter to sendSuper */
#define RECEIVER 0
#define CLASS 4
/* Selected field offsets in class structure */
#define ISA 0
#define SUPERCLASS 4
#define CACHE 8
#define CACHE_MASK 12
/* Selected field offsets in method structure */
#define METHOD_NAME 0
#define METHOD_TYPES 4
#define METHOD_IMP 8
//////////////////////////////////////////////////////////////////////
//
// ENTRY functionName
//
// Assembly directives to begin an exported function.
//
// Takes: functionName - name of the exported function
//////////////////////////////////////////////////////////////////////
.macro ENTRY /* name */
.text
.thumb
.align 5
.globl $0
.thumb_func
$0:
.endmacro
.macro STATIC_ENTRY /*name*/
.text
.thumb
.align 5
.private_extern $0
.thumb_func
$0:
.endmacro
//////////////////////////////////////////////////////////////////////
//
// END_ENTRY functionName
//
// Assembly directives to end an exported function. Just a placeholder,
// a close-parenthesis for ENTRY, until it is needed for something.
//
// Takes: functionName - name of the exported function
//////////////////////////////////////////////////////////////////////
.macro END_ENTRY /* name */
LExit$0:
.endmacro
/////////////////////////////////////////////////////////////////////
//
// CacheLookup NORMAL|STRET
// CacheLookup2 NORMAL|STRET
//
// Locate the implementation for a selector in a class's method cache.
//
// Takes:
// $0 = NORMAL, STRET
// r0 or r1 (STRET) = receiver
// r1 or r2 (STRET) = selector
// r9 = class to search in
//
// On exit: r9 clobbered
// (found) continues after CacheLookup, IMP in r12, eq set
// (not found) continues after CacheLookup2
//
/////////////////////////////////////////////////////////////////////
.macro CacheLookup
ldrh r12, [r9, #CACHE_MASK] // r12 = mask
ldr r9, [r9, #CACHE] // r9 = buckets
.if $0 == STRET
and r12, r12, r2 // r12 = index = SEL & mask
.else
and r12, r12, r1 // r12 = index = SEL & mask
.endif
add r9, r9, r12, LSL #3 // r9 = bucket = buckets+index*8
ldr r12, [r9] // r12 = bucket->sel
6:
.if $0 == STRET
teq r12, r2
.else
teq r12, r1
.endif
bne 8f
ldr r12, [r9, #4] // r12 = bucket->imp
.if $0 == STRET
tst r12, r12 // set ne for stret forwarding
.else
// eq already set for nonstret forwarding by `teq` above
.endif
.endmacro
.macro CacheLookup2
8:
cmp r12, #1
blo 8f // if (bucket->sel == 0) cache miss
it eq // if (bucket->sel == 1) cache wrap
ldreq r9, [r9, #4] // bucket->imp is before first bucket
ldr r12, [r9, #8]! // r12 = (++bucket)->sel
b 6b
8:
.endmacro
/////////////////////////////////////////////////////////////////////
//
// GetClassFromIsa return-type
//
// Given an Isa, return the class for the Isa.
//
// Takes:
// r9 = class
//
// On exit: r12 clobbered
// r9 contains the class for this Isa.
//
/////////////////////////////////////////////////////////////////////
.macro GetClassFromIsa
#if SUPPORT_INDEXED_ISA
// Note: We are doing a little wasted work here to load values we might not
// need. Branching turns out to be even worse when performance was measured.
MI_GET_ADDRESS(r12, _objc_indexed_classes)
tst.w r9, #ISA_INDEX_IS_NPI
itt ne
ubfxne r9, r9, #ISA_INDEX_SHIFT, #ISA_INDEX_BITS
ldrne.w r9, [r12, r9, lsl #2]
#endif
.endmacro
/********************************************************************
* IMP cache_getImp(Class cls, SEL sel)
*
* On entry: r0 = class whose cache is to be searched
* r1 = selector to search for
*
* If found, returns method implementation.
* If not found, returns NULL.
********************************************************************/
STATIC_ENTRY _cache_getImp
mov r9, r0
CacheLookup NORMAL
// cache hit, IMP in r12
mov r0, r12
bx lr // return imp
CacheLookup2 GETIMP
// cache miss, return nil
mov r0, #0
bx lr
END_ENTRY _cache_getImp
/********************************************************************
*
* id objc_msgSend(id self, SEL _cmd, ...) *
* objc_msgLookup ABI:
* IMP returned in r12
* Forwarding returned in Z flag
* r9 reserved for our use but not used
*
********************************************************************/
ENTRY _objc_msgSend
MESSENGER_START
cbz r0, LNilReceiver_f
ldr r9, [r0] // r9 = self->isa
GetClassFromIsa // r9 = class
CacheLookup NORMAL
// cache hit, IMP in r12, eq already set for nonstret forwarding
MESSENGER_END_FAST
bx r12 // call imp
CacheLookup2 NORMAL
// cache miss
ldr r9, [r0] // r9 = self->isa
GetClassFromIsa // r9 = class
MESSENGER_END_SLOW
b __objc_msgSend_uncached
LNilReceiver:
// r0 is already zero
mov r1, #0
mov r2, #0
mov r3, #0
FP_RETURN_ZERO
MESSENGER_END_NIL
bx lr
END_ENTRY _objc_msgSend
ENTRY _objc_msgLookup
cbz r0, LNilReceiver_f
ldr r9, [r0] // r9 = self->isa
GetClassFromIsa // r9 = class
CacheLookup NORMAL
// cache hit, IMP in r12, eq already set for nonstret forwarding
bx lr
CacheLookup2 NORMAL
// cache miss
ldr r9, [r0] // r9 = self->isa
GetClassFromIsa // r9 = class
b __objc_msgLookup_uncached
LNilReceiver:
MI_GET_ADDRESS(r12, __objc_msgNil)
bx lr
END_ENTRY _objc_msgLookup
STATIC_ENTRY __objc_msgNil
// r0 is already zero
mov r1, #0
mov r2, #0
mov r3, #0
FP_RETURN_ZERO
bx lr
END_ENTRY __objc_msgNil
/********************************************************************
* void objc_msgSend_stret(void *st_addr, id self, SEL op, ...) *
* objc_msgSend_stret is the struct-return form of msgSend.
* The ABI calls for r0 to be used as the address of the structure
* being returned, with the parameters in the succeeding registers.
*
* On entry: r0 is the address where the structure is returned,
* r1 is the message receiver,
* r2 is the selector
********************************************************************/
ENTRY _objc_msgSend_stret
MESSENGER_START
cbz r1, LNilReceiver_f
ldr r9, [r1] // r9 = self->isa
GetClassFromIsa // r9 = class
CacheLookup STRET
// cache hit, IMP in r12, ne already set for stret forwarding
MESSENGER_END_FAST
bx r12
CacheLookup2 STRET
// cache miss
ldr r9, [r1] // r9 = self->isa
GetClassFromIsa // r9 = class
MESSENGER_END_SLOW
b __objc_msgSend_stret_uncached
LNilReceiver:
MESSENGER_END_NIL
bx lr
END_ENTRY _objc_msgSend_stret
ENTRY _objc_msgLookup_stret
cbz r1, LNilReceiver_f
ldr r9, [r1] // r9 = self->isa
GetClassFromIsa // r9 = class
CacheLookup STRET
// cache hit, IMP in r12, ne already set for stret forwarding
bx lr
CacheLookup2 STRET
// cache miss
ldr r9, [r1] // r9 = self->isa
GetClassFromIsa // r9 = class
b __objc_msgLookup_stret_uncached
LNilReceiver:
MI_GET_ADDRESS(r12, __objc_msgNil_stret)
bx lr
END_ENTRY _objc_msgLookup_stret
STATIC_ENTRY __objc_msgNil_stret
bx lr
END_ENTRY __objc_msgNil_stret
/********************************************************************
* id objc_msgSendSuper(struct objc_super *super, SEL op, ...)
*
* struct objc_super {
* id receiver * }
********************************************************************/
ENTRY _objc_msgSendSuper
MESSENGER_START
ldr r9, [r0, #CLASS] // r9 = struct super->class
CacheLookup NORMAL
// cache hit, IMP in r12, eq already set for nonstret forwarding
ldr r0, [r0, #RECEIVER] // load real receiver
MESSENGER_END_FAST
bx r12 // call imp
CacheLookup2 NORMAL
// cache miss
ldr r9, [r0, #CLASS] // r9 = struct super->class
ldr r0, [r0, #RECEIVER] // load real receiver
MESSENGER_END_SLOW
b __objc_msgSend_uncached
END_ENTRY _objc_msgSendSuper
/********************************************************************
* id objc_msgSendSuper2(struct objc_super *super, SEL op, ...)
*
* struct objc_super {
* id receiver * }
********************************************************************/
ENTRY _objc_msgSendSuper2
MESSENGER_START
ldr r9, [r0, #CLASS] // class = struct super->class
ldr r9, [r9, #SUPERCLASS] // class = class->superclass
CacheLookup NORMAL
// cache hit, IMP in r12, eq already set for nonstret forwarding
ldr r0, [r0, #RECEIVER] // load real receiver
MESSENGER_END_FAST
bx r12 // call imp
CacheLookup2 NORMAL
// cache miss
ldr r9, [r0, #CLASS] // class = struct super->class
ldr r9, [r9, #SUPERCLASS] // class = class->superclass
ldr r0, [r0, #RECEIVER] // load real receiver
MESSENGER_END_SLOW
b __objc_msgSend_uncached
END_ENTRY _objc_msgSendSuper2
ENTRY _objc_msgLookupSuper2
ldr r9, [r0, #CLASS] // class = struct super->class
ldr r9, [r9, #SUPERCLASS] // class = class->superclass
CacheLookup NORMAL
// cache hit, IMP in r12, eq already set for nonstret forwarding
ldr r0, [r0, #RECEIVER] // load real receiver
bx lr
CacheLookup2 NORMAL
// cache miss
ldr r9, [r0, #CLASS]
ldr r9, [r9, #SUPERCLASS] // r9 = class to search
ldr r0, [r0, #RECEIVER] // load real receiver
b __objc_msgLookup_uncached
END_ENTRY _objc_msgLookupSuper2
/********************************************************************
* void objc_msgSendSuper_stret(void *st_addr, objc_super *self, SEL op, ...) * objc_msgSendSuper_stret is the struct-return form of msgSendSuper.
* The ABI calls for r0 to be used as the address of the structure
* being returned, with the parameters in the succeeding registers.
*
* On entry: r0 is the address where the structure is returned,
* r1 is the address of the objc_super structure,
* r2 is the selector
********************************************************************/
ENTRY _objc_msgSendSuper_stret
MESSENGER_START
ldr r9, [r1, #CLASS] // r9 = struct super->class
CacheLookup STRET
// cache hit, IMP in r12, ne already set for stret forwarding
ldr r1, [r1, #RECEIVER] // load real receiver
MESSENGER_END_FAST
bx r12 // call imp
CacheLookup2 STRET
// cache miss
ldr r9, [r1, #CLASS] // r9 = struct super->class
ldr r1, [r1, #RECEIVER] // load real receiver
MESSENGER_END_SLOW
b __objc_msgSend_stret_uncached
END_ENTRY _objc_msgSendSuper_stret
/********************************************************************
* id objc_msgSendSuper2_stret
********************************************************************/
ENTRY _objc_msgSendSuper2_stret
MESSENGER_START
ldr r9, [r1, #CLASS] // class = struct super->class
ldr r9, [r9, #SUPERCLASS] // class = class->superclass
CacheLookup STRET
// cache hit, IMP in r12, ne already set for stret forwarding
ldr r1, [r1, #RECEIVER] // load real receiver
MESSENGER_END_FAST
bx r12 // call imp
CacheLookup2 STRET
// cache miss
ldr r9, [r1, #CLASS] // class = struct super->class
ldr r9, [r9, #SUPERCLASS] // class = class->superclass
ldr r1, [r1, #RECEIVER] // load real receiver
MESSENGER_END_SLOW
b __objc_msgSend_stret_uncached
END_ENTRY _objc_msgSendSuper2_stret
ENTRY _objc_msgLookupSuper2_stret
ldr r9, [r1, #CLASS] // class = struct super->class
ldr r9, [r9, #SUPERCLASS] // class = class->superclass
CacheLookup STRET
// cache hit, IMP in r12, ne already set for stret forwarding
ldr r1, [r1, #RECEIVER] // load real receiver
bx lr
CacheLookup2 STRET
// cache miss
ldr r9, [r1, #CLASS]
ldr r9, [r9, #SUPERCLASS] // r9 = class to search
ldr r1, [r1, #RECEIVER] // load real receiver
b __objc_msgLookup_stret_uncached
END_ENTRY _objc_msgLookupSuper2_stret
/////////////////////////////////////////////////////////////////////
//
// MethodTableLookup NORMAL|STRET
//
// Locate the implementation for a selector in a class's method lists.
//
// Takes:
// $0 = NORMAL, STRET
// r0 or r1 (STRET) = receiver
// r1 or r2 (STRET) = selector
// r9 = class to search in
//
// On exit: IMP in r12, eq/ne set for forwarding
//
/////////////////////////////////////////////////////////////////////
.macro MethodTableLookup
stmfd sp!, {r0-r3,r7,lr}
add r7, sp, #16
sub sp, #8 // align stack
FP_SAVE
.if $0 == NORMAL
// receiver already in r0
// selector already in r1
.else
mov r0, r1 // receiver
mov r1, r2 // selector
.endif
mov r2, r9 // class to search
blx __class_lookupMethodAndLoadCache3
mov r12, r0 // r12 = IMP
.if $0 == NORMAL
cmp r12, r12 // set eq for nonstret forwarding
.else
tst r12, r12 // set ne for stret forwarding
.endif
FP_RESTORE
add sp, #8 // align stack
ldmfd sp!, {r0-r3,r7,lr}
.endmacro
/********************************************************************
*
* _objc_msgSend_uncached
* _objc_msgSend_stret_uncached
* _objc_msgLookup_uncached
* _objc_msgLookup_stret_uncached
* The uncached method lookup.
*
********************************************************************/
STATIC_ENTRY __objc_msgSend_uncached
// THIS IS NOT A CALLABLE C FUNCTION
// Out-of-band r9 is the class to search
MethodTableLookup NORMAL // returns IMP in r12
bx r12
END_ENTRY __objc_msgSend_uncached
STATIC_ENTRY __objc_msgSend_stret_uncached
// THIS IS NOT A CALLABLE C FUNCTION
// Out-of-band r9 is the class to search
MethodTableLookup STRET // returns IMP in r12
bx r12
END_ENTRY __objc_msgSend_stret_uncached
STATIC_ENTRY __objc_msgLookup_uncached
// THIS IS NOT A CALLABLE C FUNCTION
// Out-of-band r9 is the class to search
MethodTableLookup NORMAL // returns IMP in r12
bx lr
END_ENTRY __objc_msgLookup_uncached
STATIC_ENTRY __objc_msgLookup_stret_uncached
// THIS IS NOT A CALLABLE C FUNCTION
// Out-of-band r9 is the class to search
MethodTableLookup STRET // returns IMP in r12
bx lr
END_ENTRY __objc_msgLookup_stret_uncached
/********************************************************************
*
* id _objc_msgForward(id self, SEL _cmd,...)* _objc_msgForward and _objc_msgForward_stret are the externally-callable
* functions returned by things like method_getImplementation().
* _objc_msgForward_impcache is the function pointer actually stored in
* method caches.
*
********************************************************************/
MI_EXTERN(__objc_forward_handler)
MI_EXTERN(__objc_forward_stret_handler)
STATIC_ENTRY __objc_msgForward_impcache
// Method cache version
// THIS IS NOT A CALLABLE C FUNCTION
// Out-of-band Z is 0 (EQ) for normal, 1 (NE) for stret
MESSENGER_START
nop
MESSENGER_END_SLOW
beq __objc_msgForward
b __objc_msgForward_stret
END_ENTRY __objc_msgForward_impcache
ENTRY __objc_msgForward
// Non-stret version
MI_GET_EXTERN(r12, __objc_forward_handler)
ldr r12, [r12]
bx r12
END_ENTRY __objc_msgForward
ENTRY __objc_msgForward_stret
// Struct-return version
MI_GET_EXTERN(r12, __objc_forward_stret_handler)
ldr r12, [r12]
bx r12
END_ENTRY __objc_msgForward_stret
ENTRY _objc_msgSend_noarg
b _objc_msgSend
END_ENTRY _objc_msgSend_noarg
ENTRY _objc_msgSend_debug
b _objc_msgSend
END_ENTRY _objc_msgSend_debug
ENTRY _objc_msgSendSuper2_debug
b _objc_msgSendSuper2
END_ENTRY _objc_msgSendSuper2_debug
ENTRY _objc_msgSend_stret_debug
b _objc_msgSend_stret
END_ENTRY _objc_msgSend_stret_debug
ENTRY _objc_msgSendSuper2_stret_debug
b _objc_msgSendSuper2_stret
END_ENTRY _objc_msgSendSuper2_stret_debug
ENTRY _method_invoke
// r1 is method triplet instead of SEL
ldr r12, [r1, #METHOD_IMP]
ldr r1, [r1, #METHOD_NAME]
bx r12
END_ENTRY _method_invoke
ENTRY _method_invoke_stret
// r2 is method triplet instead of SEL
ldr r12, [r2, #METHOD_IMP]
ldr r2, [r2, #METHOD_NAME]
bx r12
END_ENTRY _method_invoke_stret
.section __DATA,__objc_msg_break
.long 0
.long 0
#endif