+
+#+sb-assembling
+(macrolet
+ ((def (reg)
+ (declare (ignorable reg))
+ #!+sb-thread
+ (let* ((name (intern (format nil "ALLOC-TLS-INDEX-IN-~A" reg)))
+ (target-offset (intern (format nil "~A-OFFSET" reg)))
+ (other-offset (if (eql 'rax reg)
+ 'rcx-offset
+ 'rax-offset)))
+ ;; Symbol starts in TARGET, where the TLS-INDEX ends up in.
+ `(define-assembly-routine ,name
+ ((:temp other descriptor-reg ,other-offset)
+ (:temp target descriptor-reg ,target-offset))
+ (let ((get-tls-index-lock (gen-label))
+ (release-tls-index-lock (gen-label)))
+ (pseudo-atomic
+ ;; Save OTHER & push the symbol. RAX is either one of the two.
+ (inst push other)
+ (inst push target)
+ (emit-label get-tls-index-lock)
+ (inst mov target 1)
+ (zeroize rax-tn)
+ (inst cmpxchg (make-ea-for-symbol-value *tls-index-lock*) target :lock)
+ (inst jmp :ne get-tls-index-lock)
+ ;; The symbol is now in OTHER.
+ (inst pop other)
+ ;; Now with the lock held, see if the symbol's tls index has been
+ ;; set in the meantime.
+ (loadw target other symbol-tls-index-slot other-pointer-lowtag)
+ (inst or target target)
+ (inst jmp :ne release-tls-index-lock)
+ ;; Allocate a new tls-index.
+ (load-symbol-value target *free-tls-index*)
+ (let ((error (generate-error-code nil 'tls-exhausted-error)))
+ (inst cmp target (fixnumize tls-size))
+ (inst jmp :ge error))
+ (inst add (make-ea-for-symbol-value *free-tls-index*)
+ (fixnumize 1))
+ (storew target other symbol-tls-index-slot other-pointer-lowtag)
+ (emit-label release-tls-index-lock)
+ (store-symbol-value 0 *tls-index-lock*)
+ ;; Restore OTHER.
+ (inst pop other))
+ (inst ret))))))
+ (def rax)
+ (def rcx)
+ (def rdx)
+ (def rbx)
+ (def rsi)
+ (def rdi)
+ (def r8)
+ (def r9)
+ (def r10)
+ (def r12)
+ (def r13)
+ (def r14)
+ (def r15))