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Diffstat (limited to 'asmcomp/reg.mli')
| -rw-r--r-- | asmcomp/reg.mli | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/asmcomp/reg.mli b/asmcomp/reg.mli index ad462c20a2..38983279ea 100644 --- a/asmcomp/reg.mli +++ b/asmcomp/reg.mli @@ -42,6 +42,29 @@ and stack_location = Local of int | Incoming of int | Outgoing of int + | Domainstate of int + +(* The [stack_location] describes the location of pseudo-registers + that reside in memory. + - [Local] is a local variable or spilled register residing in the stack frame + of the current function + - [Incoming] is a function parameter that was passed on the stack. + This is the callee's view: the location is just above the callee's + stack frame, in the caller's stack frame. + - [Outgoing] is a function call argument that is passed on the stack. + This is the caller's view: the location is at the bottom of the + caller's stack frame. + - [Domainstate] is a function call argument that is passed not on stack + but in the [extra_params] section of the domain state + (see file [../runtime/caml/domain_state.*]). Unlike arguments passed + on stack, arguments passed via the domain state are compatible with + tail calls. However, domain state locations are shared between + all functions that run in a given domain, hence they are not preserved + by function calls or thread context switches. The caller stores + arguments in the domain state immediately before the call, and the + first thing the callee does is copy them to registers or [Local] + stack locations. Neither GC nor thread context switches can occur + between these two times. *) val dummy: t val create: Cmm.machtype_component -> t |