mirror of
https://github.com/darlinghq/darling-libobjc2.git
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217 lines
7.1 KiB
ArmAsm
217 lines
7.1 KiB
ArmAsm
.set noreorder
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# Some macros for n32 / n64 compatibility
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#ifdef _ABI64
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#define LP ld
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#define SP sd
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#define DTABLE_OFFSET 64
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#define SMALLOBJ_MASK 7
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#define SHIFT_OFFSET 4
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#define DATA_OFFSET 16
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#define SLOT_OFFSET 32
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#else
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#warning N32 is untested, O32 is unsupported.
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#define LP lw
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#define SP sw
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#define DTABLE_OFFSET 32
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#define SMALLOBJ_MASK 1
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#define SHIFT_OFFSET 4
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#define DATA_OFFSET 12
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#define SLOT_OFFSET 16
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#endif
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.macro dump_and_crash reg
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nop
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move $a0, \reg
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ld $25, %got_disp(logInt)($t8)
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jalr $25
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nop
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lw $zero, ($zero)
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.endm
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// FIXME: CHERI needs (or, at least, strongly encourages) 32-byte aligned
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// stacks.
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#ifndef __mips_soft_float
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#define SAVE_SIZE 136
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#else
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#define SAVE_SIZE 72
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#endif
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.macro MSGSEND receiver, sel
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0:
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.cfi_startproc # Start emitting unwind data. We
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# don't actually care about any of
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# the stuff except the slow call,
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# because that's the only one that
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# can throw.
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beq \receiver, $0, 4f # If the receiver is nil, return nil
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nop
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lui $t8, %hi(%neg(%gp_rel(0b))) # Load the GOT address that we use for relocations into $t8
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daddu $t8, $t8, $t9
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daddiu $t8, $t8, %lo(%neg(%gp_rel(0b)))
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andi $t4, \receiver, SMALLOBJ_MASK # Check if the receiver is a small object
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bne $t4, $0, 6f # Get the small object class
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nop
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LP $t5, (\sel)
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# By this point, we have a non-nil
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# receiver that is a real pointer
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LP $t4, (\receiver) # Load the class
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1: # class loaded, stored in $t4
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LP $t4, DTABLE_OFFSET($t4) # Load the dtable from the class
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lw $t6, SHIFT_OFFSET($t4) # Load the shift (dtable size)
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# $t4 = dtable, $t5 = sel index
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LP $t7, DATA_OFFSET($t4) # Load the address of the start of the array
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beq $0, $t6, 3f # If this is a small dtable, jump to the small dtable handlers
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daddi $v0, $t6, -8
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beq $0, $v0, 2f
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lui $t6, 0x00ff # The mask for a big dtable won't fit in an and immediate
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and $t6, $t6, $t5 # mask the selector
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#ifdef _ABI64
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dsrl $t6, $t6, 13 # Right shift 16, but then left shift by pointer size
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#else
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srl $t6, $t6, 14
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#endif
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dadd $t6, $t6, $t7
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LP $t7, ($t6)
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LP $t7, DATA_OFFSET($t7)
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2: # dtable16:
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andi $t6, $t5, 0xff00 # mask the selector
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#ifdef _ABI64
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dsrl $t6, $t6, 5 # Right shift 8, but then left shift by pointer size
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#else
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srl $t6, $t6, 6
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#endif
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dadd $t6, $t6, $t7
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LP $t7, ($t6)
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LP $t7, DATA_OFFSET($t7)
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3: # dtable8:
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andi $t6, $t5, 0xff # mask the selector
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#ifdef _ABI64
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dsll $t6, $t6, 3 # Left shift by pointer size
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#else
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sll $t6, $t6, 2
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#endif
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dadd $t6, $t6, $t7
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LP $t7, ($t6)
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beq $0, $t7, 5f # Nil slot - invoke some kind of forwarding mechanism
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nop
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LP $25, SLOT_OFFSET($t7)
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jr $25
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nop
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4: # returnNil:
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# All of the return registers are
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# callee-save, so we can
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# return 0 in both in the same code:
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#ifndef __mips_soft_float
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dmtc1 $0, $f0 # Return 0 as a floating point value (only if we're not a soft-float target)
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dmtc1 $0, $f2
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#endif
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daddi $v0, $0, 0 # Return 0 as an integer
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jr $ra
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daddi $v1, $0, 0
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5: # slowSend:
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# Load the address of the slow lookup function now, so that we don't get
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# pipeline stalls on the jump. This is more important on CHERI than proper
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# MIPS implementations.
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# Note: A better linker ought to be able to turn this into a single
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# jump-immediate, so revisit this decision later...
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LP $25, %got_disp(CDECL(slowMsgLookup))($t8)
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daddiu $sp, $sp, -SAVE_SIZE # We need to preserve all registers that may contain arguments:
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SP $a0, ($sp)
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SP $a1, 8($sp)
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SP $a2, 16($sp)
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SP $a3, 24($sp)
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SP $a4, 32($sp)
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SP $a5, 40($sp)
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SP $a6, 48($sp)
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SP $a7, 56($sp)
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SP $ra, 64($sp)
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#ifndef __mips_soft_float
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sdc1 $f12, 72($sp)
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sdc1 $f13, 80($sp)
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sdc1 $f14, 88($sp)
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sdc1 $f15, 96($sp)
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sdc1 $f16, 104($sp)
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sdc1 $f17, 112($sp)
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sdc1 $f18, 120($sp)
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sdc1 $f19, 128($sp)
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#endif
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# We're (potentially) modifying the self argument with the lookup. Use the
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# address of the stack save slot for the address so that when we reload it
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# we get the old or new version automatically. Note that we must reload it
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# anyway, because argument registers are not guaranteed to be preserved
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# across calls.
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.ifc "\receiver", "$a0"
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daddiu $a0, $sp, 0 # replace self with &self in $a0
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.else
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daddiu $a0, $sp, 8 # replace sret pointer with &self in $a0
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daddiu $a1, $a2, 0 # replace self with _cmd in $a1
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.endif
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.cfi_adjust_cfa_offset -SAVE_SIZE
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jalr $25 # Call the slow lookup function
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nop
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move $25, $v0 # Move the return value to $25 for use with the call
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LP $a0, ($sp) # Restore all of the arguments. Note
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LP $a1, 8($sp) # that the receiver may have been
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LP $a2, 16($sp) # modified during the call
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LP $a3, 24($sp)
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LP $a4, 32($sp)
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LP $a5, 40($sp)
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LP $a6, 48($sp)
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LP $a7, 56($sp)
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LP $ra, 64($sp)
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#ifndef __mips_soft_float
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ldc1 $f12, 72($sp)
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ldc1 $f13, 80($sp)
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ldc1 $f14, 88($sp)
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ldc1 $f15, 96($sp)
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ldc1 $f16, 104($sp)
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ldc1 $f17, 112($sp)
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ldc1 $f18, 120($sp)
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ldc1 $f19, 128($sp)
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#endif
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jr $25
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daddiu $sp, $sp, SAVE_SIZE
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6: # smallObject:
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#if _ABI64
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dsll $t4, $t4, 3 # Convert tag to pointer offset
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LP $t6, %got_disp(CDECL(SmallObjectClasses))($t8) # Load small object classes array address
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daddu $t4, $t4, $t6 # Add the base address to the offset
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b 1b # Return to the normal path
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LP $t4, ($t4) # Load the class (in delay slot)
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#else
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b 1b
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LP $t4, %got_disp(CDECL(SmallIntClass))($t8)
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#endif
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.cfi_endproc
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.endm
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.globl CDECL(objc_msgSend)
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TYPE_DIRECTIVE(CDECL(objc_msgSend), @function)
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.globl CDECL(objc_msgSend_fpret)
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TYPE_DIRECTIVE(CDECL(objc_msgSend_fpret), @function)
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CDECL(objc_msgSend_fpret):
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CDECL(objc_msgSend):
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MSGSEND $a0, $a1
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.globl CDECL(objc_msgSend_stret)
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TYPE_DIRECTIVE(CDECL(objc_msgSend_stret), @function)
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CDECL(objc_msgSend_stret):
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MSGSEND $a1, $a2
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