2 files changed, 45 insertions, 12 deletions
diff --git a/lib/pure/nimtracker.nim b/lib/pure/nimtracker.nim
index 52fa9da77..acc242257 100644
--- a/lib/pure/nimtracker.nim
+++ b/lib/pure/nimtracker.nim
@@ -19,7 +19,15 @@ import sqlite3
 
 var
   dbHandle: PSqlite3
-  insertStmt: Pstmt
+  insertStmt {.threadvar.}: Pstmt
+
+const insertQuery = "INSERT INTO tracking(op, address, size, file, line) values (?, ?, ?, ?, ?)"
+
+when compileOption("threads"):
+  onThreadCreation do():
+    if prepare_v2(dbHandle, insertQuery,
+        insertQuery.len, insertStmt, nil) != SQLITE_OK:
+      quit "could not bind query to insertStmt " & $sqlite3.errmsg(dbHandle)
 
 template sbind(x: int; value) =
   when value is cstring:
@@ -32,7 +40,7 @@ template sbind(x: int; value) =
       quit "could not bind value"
 
 when defined(memTracker):
-  proc logEntries(log: TrackLog) {.nimcall, locks: 0, tags: [].} =
+  proc logEntries(log: TrackLog) {.nimcall, locks: 0, tags: [], gcsafe.} =
     for i in 0..log.count-1:
       var success = false
       let e = log.data[i]
@@ -46,7 +54,7 @@ when defined(memTracker):
       if step(insertStmt) == SQLITE_DONE:
         success = true
       if not success:
-        quit "could not write to database!"
+        quit "could not write to database! " & $sqlite3.errmsg(dbHandle)
 
 proc execQuery(q: string) =
   var s: Pstmt
@@ -71,10 +79,12 @@ proc setupDb() =
 if sqlite3.open("memtrack.db", dbHandle) == SQLITE_OK:
   setupDb()
   const query = "INSERT INTO tracking(op, address, size, file, line) values (?, ?, ?, ?, ?)"
-  if prepare_v2(dbHandle, query,
-      query.len, insertStmt, nil) == SQLITE_OK:
+  if prepare_v2(dbHandle, insertQuery,
+      insertQuery.len, insertStmt, nil) == SQLITE_OK:
     when defined(memTracker):
       setTrackLogger logEntries
   else:
     quit "could not prepare statement B " & $sqlite3.errmsg(dbHandle)
+else:
+  quit "could not setup sqlite " & $sqlite3.errmsg(dbHandle)
 {.pop.}
diff --git a/lib/system/memtracker.nim b/lib/system/memtracker.nim
index a9767bbca..f37b0c45a 100644
--- a/lib/system/memtracker.nim
+++ b/lib/system/memtracker.nim
@@ -28,23 +28,46 @@ type
   TrackLog* = object
     count*: int
     disabled: bool
-    data*: array[4000, LogEntry]
-  TrackLogger* = proc (log: TrackLog) {.nimcall, tags: [], locks: 0.}
+    data*: array[400, LogEntry]
+  TrackLogger* = proc (log: TrackLog) {.nimcall, tags: [], locks: 0, gcsafe.}
 
 var
   gLog*: TrackLog
   gLogger*: TrackLogger = proc (log: TrackLog) = discard
+  ilocs: array[4000, (int, int)]
+  ilocn: int
+
+proc trackLocation*(p: pointer; size: int) =
+  let x = (cast[int](p), size)
+  for i in 0..ilocn-1:
+    # already known?
+    if ilocs[i] == x: return
+  ilocs[ilocn] = x
+  inc ilocn
 
 proc setTrackLogger*(logger: TrackLogger) =
   gLogger = logger
 
 proc addEntry(entry: LogEntry) =
   if not gLog.disabled:
-    if gLog.count > high(gLog.data):
-      gLogger(gLog)
-      gLog.count = 0
-    gLog.data[gLog.count] = entry
-    inc gLog.count
+    var interesting = false
+    for i in 0..ilocn-1:
+      let p = ilocs[i]
+      #  X..Y and C..D overlap iff (X <= D and C <= Y)
+      let x = p[0]
+      let y = p[0]+p[1]-1
+      let c = cast[int](entry.address)
+      let d = c + entry.size-1
+      if x <= d and c <= y:
+        interesting = true
+        break
+    if interesting:
+      cprintf("interesting %s:%ld\n", entry.file, entry.line)
+      if gLog.count > high(gLog.data):
+        gLogger(gLog)
+        gLog.count = 0
+      gLog.data[gLog.count] = entry
+      inc gLog.count
 
 proc memTrackerWrite(address: pointer; size: int; file: cstring; line: int) {.compilerProc.} =
   addEntry LogEntry(op: "write", address: address,