+ ;; FIXME: Should this be :SB-CYCLE-COUNTER instead? If so, then the same goes
+ ;; for :COMPARE-AND-SWAP-VOPS as well, and a bunch of others. Perhaps
+ ;; built-time convenience features like this should all live in eg. SB!INT
+ ;; instead?
+ ;;
+ ; :cycle-counter
+
+ ;; Enabled automatically for platforms which implement complex arithmetic
+ ;; VOPs. Such platforms should implement real-complex, complex-real and
+ ;; complex-complex addition and subtractions (for complex-single-float
+ ;; and complex-double-float). They should also also implement complex-real
+ ;; and real-complex multiplication, complex-real division, and
+ ;; sb!vm::swap-complex, which swaps the real and imaginary parts.
+ ;; Finally, they should implement conjugate and complex-real, real-complex
+ ;; and complex-complex CL:= (complex-complex EQL would usually be a good
+ ;; idea).
+ ;;
+ ; :complex-float-vops
+
+ ;; Enabled automatically for platforms which implement VOPs for EQL
+ ;; of single and double floats.
+ ;;
+ ; :float-eql-vops
+
+ ;; Enabled automatically for platform that can implement inline constants.
+ ;;
+ ;; Such platform must implement 5 functions, in SB!VM:
+ ;; * canonicalize-inline-constant: converts a constant descriptor (list) into
+ ;; a canonical description, to be used as a key in an EQUAL hash table
+ ;; and to guide the generation of the constant itself.
+ ;; * inline-constant-value: given a canonical constant descriptor, computes
+ ;; two values:
+ ;; 1. A label that will be used to emit the constant (usually a
+ ;; sb!assem:label)
+ ;; 2. A value that will be returned to code generators referring to
+ ;; the constant (on x86oids, an EA object)
+ ;; * sort-inline-constants: Receives a vector of unique constants;
+ ;; the car of each entry is the constant descriptor, and the cdr the
+ ;; corresponding label. Destructively returns a vector of constants
+ ;; sorted in emission order. It could actually perform arbitrary
+ ;; modifications to the vector, e.g. to fuse constants of different
+ ;; size.
+ ;; * emit-constant-segment-header: receives the vector of sorted constants
+ ;; and a flag (true iff speed > space). Expected to emit padding
+ ;; of some sort between the ELSEWHERE segment and the constants, or some
+ ;; metadata.
+ ;; * emit-inline-constant: receives a constant descriptor and its associated
+ ;; label. Emits the constant.
+ ;;
+ ;; Implementing this features lets VOP generators use sb!c:register-inline-constant
+ ;; to get handles (as returned by sb!vm:inline-constant-value) from constant
+ ;; descriptors.
+ ;;
+ ; :inline-constants
+
+ ;; Peter Van Eynde's increase-bulletproofness code for CMU CL
+ ;;
+ ;; Some of the code which was #+high-security before the fork has now
+ ;; been either made unconditional, deleted, or rewritten into
+ ;; unrecognizability, but some remains. What remains is not maintained
+ ;; or tested in current SBCL, but I haven't gone out of my way to
+ ;; break it, either.