VM profiler (#14833)

* Crude VM profiler

* Added --profileVM flag, refactoring

* fixed FileLine hash

* Use TLineInfo instead of own FileLine, updated formatting

* Refactoring, moved PStackFrame to vmdefs for cleaner data structure

* Moved vmprofiler to separate file

* Simplified TLineInfo hash, use toFileLineCol for output

* Hash

* Moved profile data into Config, dump only once at end of run

* Changed profile output header to show '#instr' instead of 'count'

* Do not accumulate instrcount for non-top frames

Co-authored-by: Ico Doornekamp <git@zevv.nl>

compiler/vmprofiler.nim

@@ -0,0 +1,42 @@
+
+import
+  options, vmdef, times, lineinfos, strutils, tables,
+  msgs
+  
+proc enter*(prof: var Profiler, c: PCtx, tos: PStackFrame) {.inline.} =
+  if optProfileVM in c.config.globalOptions:
+    prof.tEnter = cpuTime()
+    prof.tos = tos
+
+proc leave*(prof: var Profiler, c: PCtx) {.inline.} =
+  if optProfileVM in c.config.globalOptions:
+    let tLeave = cpuTime()
+    var tos = prof.tos
+    var data = c.config.vmProfileData.data
+    while tos != nil:
+      if tos.prc != nil:
+        let li = tos.prc.info
+        if li notin data:
+          data[li] = ProfileInfo()
+        data[li].time += tLeave - prof.tEnter
+        if tos == prof.tos:
+          inc data[li].count
+      tos = tos.next
+
+proc dump*(conf: ConfigRef, pd: ProfileData): string =
+  var data = pd.data
+  echo "\nprof:     µs    #instr  location"
+  for i in 0..<32:
+    var tMax: float
+    var infoMax: ProfileInfo
+    var flMax: TLineInfo
+    for fl, info in data:
+      if info.time > infoMax.time:
+        infoMax = info
+        flMax = fl
+    if infoMax.count == 0:
+      break
+    result.add  "  " & align($int(infoMax.time * 1e6), 10) &
+                       align($int(infoMax.count), 10) & "  " &
+                       conf.toFileLineCol(flMax) & "\n"
+    data.del flMax