Expose GC_setStackBottom (#7885)

lib/system.nim

@@ -1523,7 +1523,6 @@ const hasAlloc = (hostOS != "standalone" or not defined(nogc)) and not defined(n
 when not defined(JS) and not defined(nimscript) and hostOS != "standalone":
   include "system/cgprocs"
 when not defined(JS) and not defined(nimscript) and hasAlloc:
-  proc setStackBottom(theStackBottom: pointer) {.compilerRtl, noinline, benign.}
   proc addChar(s: NimString, c: char): NimString {.compilerProc, benign.}
 
 proc add *[T](x: var seq[T], y: T) {.magic: "AppendSeqElem", noSideEffect.}
@@ -2639,6 +2638,11 @@ when not defined(nimscript) and hasAlloc:
     proc GC_unref*(x: string) {.magic: "GCunref", benign.}
       ## see the documentation of `GC_ref`.
 
+    when not defined(JS) and not defined(nimscript) and hasAlloc:
+      proc nimGC_setStackBottom*(theStackBottom: pointer) {.compilerRtl, noinline, benign.}
+      ## Expands operating GC stack range to `theStackBottom`. Does nothing
+      ## if current stack bottom is already lower than `theStackBottom`.
+
   else:
     template GC_disable* =
       {.warning: "GC_disable is a no-op in JavaScript".}
@@ -2898,16 +2902,16 @@ when not defined(JS): #and not defined(nimscript):
       # WARNING: This is very fragile! An array size of 8 does not work on my
       # Linux 64bit system. -- That's because the stack direction is the other
       # way round.
-      when declared(setStackBottom):
+      when declared(nimGC_setStackBottom):
         var locals {.volatile.}: pointer
         locals = addr(locals)
-        setStackBottom(locals)
+        nimGC_setStackBottom(locals)
 
     proc initStackBottomWith(locals: pointer) {.inline, compilerproc.} =
       # We need to keep initStackBottom around for now to avoid
       # bootstrapping problems.
-      when declared(setStackBottom):
+      when declared(nimGC_setStackBottom):
-        setStackBottom(locals)
+        nimGC_setStackBottom(locals)
 
     {.push profiler: off.}
     var

lib/system/gc_common.nim

@@ -200,7 +200,7 @@ when declared(threadType):
     if threadType == ThreadType.None:
       initAllocator()
       var stackTop {.volatile.}: pointer
-      setStackBottom(addr(stackTop))
+      nimGC_setStackBottom(addr(stackTop))
       initGC()
       threadType = ThreadType.ForeignThread
 
@@ -257,7 +257,7 @@ when nimCoroutines:
     gch.activeStack.setPosition(addr(sp))
 
 when not defined(useNimRtl):
-  proc setStackBottom(theStackBottom: pointer) =
+  proc nimGC_setStackBottom(theStackBottom: pointer) =
     # Initializes main stack of the thread.
     when nimCoroutines:
       if gch.stack.next == nil:

lib/system/gc_regions.nim

@@ -401,7 +401,7 @@ proc getFreeMem*(r: MemRegion): int = r.remaining
 proc getTotalMem*(r: MemRegion): int =
   result = r.totalSize
 
-proc setStackBottom(theStackBottom: pointer) = discard
+proc nimGC_setStackBottom(theStackBottom: pointer) = discard
 
 proc nimGCref(x: pointer) {.compilerProc.} = discard
 proc nimGCunref(x: pointer) {.compilerProc.} = discard

lib/system/mmdisp.nim

@@ -146,7 +146,7 @@ when defined(boehmgc):
     proc getFreeMem(): int = return boehmGetFreeBytes()
     proc getTotalMem(): int = return boehmGetHeapSize()
 
-    proc setStackBottom(theStackBottom: pointer) = discard
+    proc nimGC_setStackBottom(theStackBottom: pointer) = discard
 
   proc initGC() =
     boehmGCinit()
@@ -305,7 +305,7 @@ elif defined(gogc):
     goRuntime_ReadMemStats(addr mstats)
     result = int(mstats.sys)
 
-  proc setStackBottom(theStackBottom: pointer) = discard
+  proc nimGC_setStackBottom(theStackBottom: pointer) = discard
 
   proc alloc(size: Natural): pointer =
     result = c_malloc(size)
@@ -449,7 +449,7 @@ elif defined(nogc) and defined(useMalloc):
     proc getFreeMem(): int = discard
     proc getTotalMem(): int = discard
 
-    proc setStackBottom(theStackBottom: pointer) = discard
+    proc nimGC_setStackBottom(theStackBottom: pointer) = discard
 
   proc initGC() = discard
 
@@ -523,7 +523,7 @@ elif defined(nogc):
   proc growObj(old: pointer, newsize: int): pointer =
     result = realloc(old, newsize)
 
-  proc setStackBottom(theStackBottom: pointer) = discard
+  proc nimGC_setStackBottom(theStackBottom: pointer) = discard
   proc nimGCref(p: pointer) {.compilerproc, inline.} = discard
   proc nimGCunref(p: pointer) {.compilerproc, inline.} = discard
 

lib/system/threads.nim

@@ -440,7 +440,7 @@ proc threadProcWrapStackFrame[TArg](thrd: ptr Thread[TArg]) =
       threadProcWrapDispatch[TArg]
     when not hasSharedHeap:
       # init the GC for refc/markandsweep
-      setStackBottom(addr(p))
+      nimGC_setStackBottom(addr(p))
       initGC()
       when declared(threadType):
         threadType = ThreadType.NimThread