Replaced ignoreStackAndRegisters with stackSize in GC_step

2 files changed, 48 insertions, 28 deletions

diff --git a/lib/system/gc.nim b/lib/system/gc.nim
index 85bdf04fe..5c2170a17 100644
--- a/lib/system/gc.nim
+++ b/lib/system/gc.nim
@@ -905,19 +905,19 @@ proc unmarkStackAndRegisters(gch: var GcHeap) =
     #sysAssert c.typ != nil, "unmarkStackAndRegisters 2"
   gch.decStack.len = 0
 
-proc collectCTBody(gch: var GcHeap, ignoreStackAndRegisters = false) =
+proc collectCTBody(gch: var GcHeap) =
   when withRealTime:
     let t0 = getticks()
   sysAssert(allocInv(gch.region), "collectCT: begin")
+
+  when not defined(nimCoroutines):
+    gch.stat.maxStackSize = max(gch.stat.maxStackSize, stackSize())
   sysAssert(gch.decStack.len == 0, "collectCT")
   prepareForInteriorPointerChecking(gch.region)
-  if not ignoreStackAndRegisters:
-    when not defined(nimCoroutines):
-      gch.stat.maxStackSize = max(gch.stat.maxStackSize, stackSize())
-    markStackAndRegisters(gch)
-    markThreadStacks(gch)
-    gch.stat.maxStackCells = max(gch.stat.maxStackCells, gch.decStack.len)
-    inc(gch.stat.stackScans)
+  markStackAndRegisters(gch)
+  markThreadStacks(gch)
+  gch.stat.maxStackCells = max(gch.stat.maxStackCells, gch.decStack.len)
+  inc(gch.stat.stackScans)
   if collectZCT(gch):
     when cycleGC:
       if getOccupiedMem(gch.region) >= gch.cycleThreshold or alwaysCycleGC:
@@ -927,8 +927,7 @@ proc collectCTBody(gch: var GcHeap, ignoreStackAndRegisters = false) =
         gch.cycleThreshold = max(InitialCycleThreshold, getOccupiedMem() *
                                  CycleIncrease)
         gch.stat.maxThreshold = max(gch.stat.maxThreshold, gch.cycleThreshold)
-  if not ignoreStackAndRegisters:
-    unmarkStackAndRegisters(gch)
+  unmarkStackAndRegisters(gch)
   sysAssert(allocInv(gch.region), "collectCT: end")
 
   when withRealTime:
@@ -972,17 +971,28 @@ when withRealTime:
   proc GC_setMaxPause*(MaxPauseInUs: int) =
     gch.maxPause = MaxPauseInUs.toNano
 
-  proc GC_step(gch: var GcHeap, us: int, strongAdvice: bool, ignoreStackAndRegisters: bool) =
+  proc GC_step(gch: var GcHeap, us: int, strongAdvice: bool) =
     acquire(gch)
     gch.maxPause = us.toNano
     if (gch.zct.len >= ZctThreshold or (cycleGC and
         getOccupiedMem(gch.region)>=gch.cycleThreshold) or alwaysGC) or
         strongAdvice:
-      collectCTBody(gch, ignoreStackAndRegisters)
+      collectCTBody(gch)
     release(gch)
 
-  proc GC_step*(us: int, strongAdvice, ignoreStackAndRegisters = false) =
-    GC_step(gch, us, strongAdvice, ignoreStackAndRegisters)
+  proc GC_step*(us: int, strongAdvice = false, stackSize = -1) {.noinline.} =
+    var stackTop {.volatile.}: pointer
+    let prevStackBottom = gch.stackBottom
+    if stackSize >= 0:
+      stackTop = addr(stackTop)
+      when stackIncreases:
+        gch.stackBottom = cast[pointer](
+          cast[ByteAddress](stackTop) - sizeof(pointer) * 6 - stackSize)
+      else:
+        gch.stackBottom = cast[pointer](
+          cast[ByteAddress](stackTop) + sizeof(pointer) * 6 + stackSize)
+    GC_step(gch, us, strongAdvice)
+    gch.stackBottom = prevStackBottom
 
 when not defined(useNimRtl):
   proc GC_disable() =
diff --git a/lib/system/gc2.nim b/lib/system/gc2.nim
index f2d1397b4..7d54c07be 100644
--- a/lib/system/gc2.nim
+++ b/lib/system/gc2.nim
@@ -894,18 +894,18 @@ proc unmarkStackAndRegisters(gch: var GcHeap) =
     decRef(d[i])
   gch.decStack.len = 0
 
-proc collectCTBody(gch: var GcHeap, ignoreStackAndRegisters = false) =
+proc collectCTBody(gch: var GcHeap) =
   when withRealTime:
     let t0 = getticks()
   sysAssert(allocInv(gch.region), "collectCT: begin")
+
+  when not defined(nimCoroutines):
+    gch.stat.maxStackSize = max(gch.stat.maxStackSize, stackSize())
   sysAssert(gch.decStack.len == 0, "collectCT")
   prepareForInteriorPointerChecking(gch.region)
-  if not ignoreStackAndRegisters:
-    when not defined(nimCoroutines):
-      gch.stat.maxStackSize = max(gch.stat.maxStackSize, stackSize())
-    markStackAndRegisters(gch)
-    gch.stat.maxStackCells = max(gch.stat.maxStackCells, gch.decStack.len)
-    inc(gch.stat.stackScans)
+  markStackAndRegisters(gch)
+  gch.stat.maxStackCells = max(gch.stat.maxStackCells, gch.decStack.len)
+  inc(gch.stat.stackScans)
   if collectZCT(gch):
     when cycleGC:
       if getOccupiedMem(gch.region) >= gch.cycleThreshold or alwaysCycleGC:
@@ -914,8 +914,7 @@ proc collectCTBody(gch: var GcHeap, ignoreStackAndRegisters = false) =
           gch.cycleThreshold = max(InitialCycleThreshold, getOccupiedMem() *
                                    CycleIncrease)
           gch.stat.maxThreshold = max(gch.stat.maxThreshold, gch.cycleThreshold)
-  if not ignoreStackAndRegisters:
-    unmarkStackAndRegisters(gch)
+  unmarkStackAndRegisters(gch)
   sysAssert(allocInv(gch.region), "collectCT: end")
 
   when withRealTime:
@@ -950,15 +949,26 @@ when withRealTime:
   proc GC_setMaxPause*(MaxPauseInUs: int) =
     gch.maxPause = MaxPauseInUs.toNano
 
-  proc GC_step(gch: var GcHeap, us: int, strongAdvice, ignoreStackAndRegisters: bool) =
+  proc GC_step(gch: var GcHeap, us: int, strongAdvice: bool) =
     gch.maxPause = us.toNano
     if (gch.zct.len >= ZctThreshold or (cycleGC and
         getOccupiedMem(gch.region)>=gch.cycleThreshold) or alwaysGC) or
         strongAdvice:
-      collectCTBody(gch, ignoreStackAndRegisters)
-
-  proc GC_step*(us: int, strongAdvice, ignoreStackAndRegisters = false) =
-    GC_step(gch, us, strongAdvice, ignoreStackAndRegisters)
+      collectCTBody(gch)
+
+  proc GC_step*(us: int, strongAdvice = false, stackSize = -1) {.noinline.} =
+    var stackTop {.volatile.}: pointer
+    let prevStackBottom = gch.stackBottom
+    if stackSize >= 0:
+      stackTop = addr(stackTop)
+      when stackIncreases:
+        gch.stackBottom = cast[pointer](
+          cast[ByteAddress](stackTop) - sizeof(pointer) * 6 - stackSize)
+      else:
+        gch.stackBottom = cast[pointer](
+          cast[ByteAddress](stackTop) + sizeof(pointer) * 6 + stackSize)
+    GC_step(gch, us, strongAdvice)
+    gch.stackBottom = prevStackBottom
 
 when not defined(useNimRtl):
   proc GC_disable() =