Slotted in JAPL's old memory manager and fixed strings. Preliminary work for GC

src/backend/vm.nim

@@ -21,6 +21,7 @@ import std/math
 import ../config
 import ../frontend/meta/bytecode
 import ../util/multibyte
+import ../memory/allocator
 
 
 import strutils
@@ -306,6 +307,18 @@ proc constReadFloat64(self: PeonVM, idx: int): float =
                self.chunk.consts[idx + 4], self.chunk.consts[idx + 5], 
                self.chunk.consts[idx + 6], self.chunk.consts[idx + 7]]
     copyMem(result.addr, arr.addr, sizeof(arr))
+
+
+proc constReadString(self: PeonVM, size, idx: int): ptr UncheckedArray[char] =
+    ## Reads a constant from the 
+    ## chunk's constant table and
+    ## returns it as a pointer to
+    ## a heap-allocated string
+    let str = self.chunk.consts[idx..<idx + size].fromBytes()
+    result = allocate(UncheckedArray[char], char, len(str))
+    for i, c in str:
+        result[i] = c
+
 {.pop.}
 
 
@@ -398,10 +411,7 @@ proc dispatch*(self: PeonVM) =
             of LoadString:
                 # TODO: Use constReadString with own memory manager
                 # Strings are broken rn!!
-                let size = int(self.readLong())
-                let idx = int(self.readLong())
-                var str = self.chunk.consts[idx..<idx + size].fromBytes()
-                self.push(cast[uint64](str.addr))
+                self.push(cast[uint64](self.constReadString(int(self.readLong()), int(self.readLong()))))
             # We cast instead of converting because, unlike with integers,
             # we don't want nim to touch any of the bits of the underlying
             # value!
@@ -671,7 +681,7 @@ proc dispatch*(self: PeonVM) =
             of PrintNan:
                 echo "nan"
             of PrintString:
-                echo cast[ptr string](self.pop())[]  # TODO
+                echo $cast[ptr UncheckedArray[char]](self.pop())  # TODO
             of SysClock64:
                 # Pushes the value of a monotonic clock
                 # onto the operand stack. This can be used

src/main.nim

@@ -1,3 +1,19 @@
+# Copyright 2022 Mattia Giambirtone & All Contributors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+## Peon's main executable
+
 # Builtins & external libs
 import std/strformat
 import std/strutils
@@ -67,6 +83,8 @@ proc repl =
                 continue
             elif input == "#reset":
                 compiled = newChunk()
+                compiler = newCompiler()
+                parser = newParser()
                 incremental = false
                 continue
             elif input == "#clear":

src/memory/allocator.nim

@@ -25,7 +25,7 @@ when debugMem:
 proc reallocate*(p: pointer, oldSize: int, newSize: int): pointer =
     ## Simple wrapper around realloc/dealloc
     try:
-        if newSize == 0 and p != nil:
+        if newSize == 0 and not p.isNil():
             when debugMem:
                 if oldSize > 1:
                     echo &"DEBUG - Memory manager: Deallocating {oldSize} bytes"
@@ -33,10 +33,7 @@ proc reallocate*(p: pointer, oldSize: int, newSize: int): pointer =
                     echo "DEBUG - Memory manager: Deallocating 1 byte"
             dealloc(p)
             return nil
-        when debugMem:
-            if pointr == nil and newSize == 0:
-                echo &"DEBUG - Memory manager: Warning, asked to dealloc() nil pointer from {oldSize} to {newSize} bytes, ignoring request"
-        if oldSize > 0 and p != nil or oldSize == 0:
+        if oldSize > 0 and not p.isNil() or oldSize == 0:
             when debugMem:
                 if oldSize == 0:
                     if newSize > 1:
@@ -46,22 +43,40 @@ proc reallocate*(p: pointer, oldSize: int, newSize: int): pointer =
                 else:
                     echo &"DEBUG - Memory manager: Resizing {oldSize} bytes of memory to {newSize} bytes"
             result = realloc(p, newSize)
+
         when debugMem:
-            if oldSize > 0 and pointr == nil:
+            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"
     except NilAccessDefect:
         stderr.write("Peon: could not manage memory, segmentation fault\n")
         quit(139) # For now, there's not much we can do if we can't get the memory we need, so we exit
 
+type
+    ObjectKind* = enum
+        String, List,
+        Dict, Tuple,
+        CustomType
+    HeapObject* = object
+        ## A tag for a heap-allocated
+        ## peon object
+        case kind*: ObjectKind
+            of String:
+                str*: ptr UncheckedArray[char]
+                len*: uint64
+            else:
+                discard  # TODO
+
 
 template resizeArray*(kind: untyped, p: pointer, oldCount, newCount: int): untyped =
     ## Handy template to resize a dynamic array
     cast[ptr UncheckedArray[kind]](reallocate(p, sizeof(kind) * oldCount, sizeof(kind) * newCount))
 
 
-template freeArray*(kind: untyped, p: pointer, oldCount: int): untyped =
+template freeArray*(kind: untyped, p: pointer, size: int): untyped =
     ## Frees a dynamic array
-    reallocate(p, sizeof(kind) * oldCount, 0)
+    reallocate(p, sizeof(kind) * size, 0)
 
 
 template free*(kind: untyped, p: pointer): untyped =