From 1e29796278c1d14bba77f8dad74f761e9b3461ee Mon Sep 17 00:00:00 2001
From: Mattia Giambirtone <nocturn9x@nocturn9x.space>
Date: Fri, 4 Nov 2022 15:30:22 +0100
Subject: [PATCH] Simplified reallocate() and more failed attempts at fixing GC
 issues

---
 src/backend/vm.nim | 27 ++++++++++-----------------
 src/config.nim     |  2 +-
 tests/gc.pn        |  6 +++---
 3 files changed, 14 insertions(+), 21 deletions(-)

diff --git a/src/backend/vm.nim b/src/backend/vm.nim
index 689ea94..73dc7be 100644
--- a/src/backend/vm.nim
+++ b/src/backend/vm.nim
@@ -114,7 +114,7 @@ proc collect*(self: var PeonVM)
 
 
 proc reallocate*(self: var PeonVM, p: pointer, oldSize: int, newSize: int): pointer =
-    ## Simple wrapper around realloc/dealloc with
+    ## Simple wrapper around realloc with
     ## built-in garbage collection
     self.gc.bytesAllocated.current += newSize - oldSize
     try:
@@ -124,14 +124,7 @@ proc reallocate*(self: var PeonVM, p: pointer, oldSize: int, newSize: int): poin
                     echo &"DEBUG - Memory manager: Deallocating {oldSize} bytes of memory"
                 else:
                     echo "DEBUG - Memory manager: Deallocating 1 byte of memory"
-            dealloc(p)
         elif (oldSize > 0 and not p.isNil() and newSize > oldSize) or oldSize == 0:
-            self.gc.bytesAllocated.total += newSize - oldSize
-            when debugStressGC:
-                self.collect()
-            else:
-                if self.gc.bytesAllocated.current > self.gc.nextGC:
-                    self.collect()
             when debugMem:
                 if oldSize == 0:
                     if newSize > 1:
@@ -140,18 +133,18 @@ proc reallocate*(self: var PeonVM, p: pointer, oldSize: int, newSize: int): poin
                         echo "DEBUG - Memory manager: Allocating 1 byte of memory"
                 else:
                     echo &"DEBUG - Memory manager: Resizing {oldSize} bytes of memory to {newSize} bytes"
-            result = realloc(p, newSize)
-        when debugMem:
-            if p.isNil() and newSize == 0:
-                echo &"DEBUG - Memory manager: Warning, asked to dealloc() nil pointer from {oldSize} to {newSize} bytes, ignoring request"
-            elif oldSize > 0 and p.isNil():
-                echo &"DEBUG - Memory manager: Warning, asked to realloc() nil pointer from {oldSize} to {newSize} bytes, ignoring request"
+            self.gc.bytesAllocated.total += newSize - oldSize
+            when debugStressGC:
+                self.collect()
+            else:
+                if self.gc.bytesAllocated.current > self.gc.nextGC:
+                    self.collect()
+        result = realloc(p, newSize)
     except NilAccessDefect:
-        stderr.write("Peon: could not manage memory, segmentation fault\n")
+        stderr.writeLine("Peon: could not manage memory, segmentation fault")
         quit(139) # For now, there's not much we can do if we can't get the memory we need, so we exit
 
 
-
 template resizeArray*(self: var PeonVM, kind: untyped, p: pointer, oldCount, newCount: int): untyped =
     ## Handy template to resize a dynamic array
     cast[ptr UncheckedArray[kind]](reallocate(self, p, sizeof(kind) * oldCount, sizeof(kind) * newCount))
@@ -178,9 +171,9 @@ proc allocate*(self: var PeonVM, kind: ObjectKind, size: typedesc, count: int):
         of String:
             result.str = cast[ptr UncheckedArray[char]](self.reallocate(nil, 0, sizeof(size) * count))
             result.len = count
-            self.gc.bytesAllocated.current += sizeof(size) * count
         else:
             discard  # TODO
+    self.gc.bytesAllocated.current += sizeof(size) * count
     self.gc.objects.add(result)
     self.gc.pointers.incl(cast[uint64](result))
 
diff --git a/src/config.nim b/src/config.nim
index bbc53a7..f7d8567 100644
--- a/src/config.nim
+++ b/src/config.nim
@@ -26,7 +26,7 @@ const debugSerializer* {.booldefine.} = false  # Validate the bytecode serialize
 const debugStressGC* {.booldefine.} = false    # Make the GC run a collection at every allocation (VERY SLOW!)
 const PeonBytecodeMarker* = "PEON_BYTECODE"    # Magic value at the beginning of bytecode files
 const HeapGrowFactor* = 2                      # The growth factor used by the GC to schedule the next collection
-const FirstGC* = 1024 * 1024;                  # How many bytes to allocate before running the first GC
+const FirstGC* = 1024;                         # How many bytes to allocate before running the first GC
 const enableVMChecks* {.booldefine.} = true;   # Enables all types of compiler (nim-wise) checks in the VM
 # List of paths where peon looks for modules, in order (empty path means current directory, which always takes precedence)
 const moduleLookupPaths*: seq[string] = @["", "src/peon/stdlib"]
diff --git a/tests/gc.pn b/tests/gc.pn
index 311ec39..9f0b330 100644
--- a/tests/gc.pn
+++ b/tests/gc.pn
@@ -1,14 +1,14 @@
 import std;
 
 
-var x: uint64 = 1000000'u64;
+var x = 10000;
 var y = "just a test";
 print(y);
 print("Starting GC torture test");
 print(x);
-while x > 0'u64 {
+while x > 0 {
     "hello";
-    x = x - 1'u64;
+    x = x - 1;
 }
 print("END");
 print(y);