fix: update LBounds tables

LBound PTR MUST always be allocated in the stack.
If it's a zero-based array, it just contains a NULL (0x0000) pointer.

The Array alloc routine will not use the ubound pointer if it's 0.

Author: boriel

src/arch/z80/backend/generic.py

@@ -272,12 +272,13 @@ def _larrd(ins: Quad):
     if not isinstance(bounds, list) or len(bounds) not in (0, 2):
         raise InvalidIC(ins, "Bounds list length must be 0 or 2, not %s" % ins[5])
 
-    if bounds:
+    have_bounds = bounds and any(x != "0" for x in bounds)
+    if have_bounds:
         output.extend(
             [
-                "ld hl, %s" % bounds[1],
+                "ld hl, %s" % bounds[1],  # UBOUND Table PTR
                 "push hl",
-                "ld hl, %s" % bounds[0],
+                "ld hl, %s" % bounds[0],  # LBOUND Table PTR
                 "push hl",
             ]
         )
@@ -297,12 +298,12 @@ def _larrd(ins: Quad):
     )
 
     if must_initialize:
-        if not bounds:
+        if not have_bounds:
             output.append(runtime_call(RuntimeLabel.ALLOC_INITIALIZED_LOCAL_ARRAY))
         else:
             output.append(runtime_call(RuntimeLabel.ALLOC_INITIALIZED_LOCAL_ARRAY_WITH_BOUNDS))
     else:
-        if not bounds:
+        if not have_bounds:
             output.append(runtime_call(RuntimeLabel.ALLOC_LOCAL_ARRAY))
         else:
             output.append(runtime_call(RuntimeLabel.ALLOC_LOCAL_ARRAY_WITH_BOUNDS))

src/arch/z80/visitor/function_translator.py

@@ -59,21 +59,17 @@ def visit_FUNCTION(self, node):
                 continue
 
             if local_var.class_ == CLASS.array and local_var.scope == SCOPE.local:
-                bound_ptrs = []  # Bound tables pointers (empty if not used)
                 lbound_label = local_var.mangled + ".__LBOUND__"
                 ubound_label = local_var.mangled + ".__UBOUND__"
 
-                if local_var.lbound_used or local_var.ubound_used:
-                    bound_ptrs = ["0", "0"]  # NULL by default
-                    if local_var.lbound_used:
-                        bound_ptrs[0] = lbound_label
-                    if local_var.ubound_used:
-                        bound_ptrs[1] = ubound_label
+                bound_ptrs = ["0" if local_var.is_zero_based else lbound_label, "0"]
+                if local_var.ubound_used:
+                    bound_ptrs[1] = ubound_label
 
-                if bound_ptrs:
+                if bound_ptrs != ["0", "0"]:
                     OPTIONS["__DEFINES"].value["__ZXB_USE_LOCAL_ARRAY_WITH_BOUNDS__"] = ""
 
-                if local_var.lbound_used:
+                if not local_var.is_zero_based:
                     l = ["%04X" % bound.lower for bound in local_var.bounds]
                     bound_tables.append(LabelledData(lbound_label, l))
 
@@ -121,6 +117,7 @@ def visit_FUNCTION(self, node):
                 if local_var.type_ == self.TYPE(TYPE.string):
                     if local_var.class_ == CLASS.const or local_var.token == "FUNCTION":
                         continue
+
                     # Only if it's string we free it
                     if local_var.class_ != CLASS.array:  # Ok just free it
                         if scope == SCOPE.local or (scope == SCOPE.parameter and not local_var.byref):

src/arch/z80/visitor/var_translator.py

@@ -46,11 +46,11 @@ def visit_ARRAYDECL(self, node):
 
         lbound_label = entry.mangled + ".__LBOUND__"
         ubound_label = entry.mangled + ".__UBOUND__"
-
-        is_zero_based_array = all(bound.lower == 0 for bound in node.bounds)
         bound_ptrs = ["0", "0"]  # NULL by default
-        if entry.lbound_used or not is_zero_based_array:
+
+        if not entry.is_zero_based:
             bound_ptrs[0] = lbound_label
+
         if entry.ubound_used or OPTIONS.array_check:
             bound_ptrs[1] = ubound_label
 

src/lib/arch/zx48k/runtime/array/arrayalloc.asm

@@ -41,7 +41,7 @@ __ALLOC_LOCAL_ARRAY:
 ; ---------------------------------------------------------------------
 ; __ALLOC_INITIALIZED_LOCAL_ARRAY
 ;  Allocates an array element area in the heap, and clears it filling it
-;  with 0 bytes
+;  with data whose pointer (PTR) is in the stack
 ;
 ; Parameters
 ;  HL = Offset to be added to IX => HL = IX + HL
@@ -99,12 +99,15 @@ __ALLOC_LOCAL_ARRAY_WITH_BOUNDS2:
     ld (hl), e
     inc hl
     ld (hl), d
-    pop de
+    pop de   ;; PTR to ubound table
+    push bc  ;; puts ret address back
+    ld a, d
+    or e
+    ret z    ;; if PTR for UBound is 0, it's not used
     inc hl
     ld (hl), e
     inc hl
     ld (hl), d
-    push bc
     ret
 
 

src/lib/arch/zxnext/runtime/array/arrayalloc.asm

@@ -41,7 +41,7 @@ __ALLOC_LOCAL_ARRAY:
 ; ---------------------------------------------------------------------
 ; __ALLOC_INITIALIZED_LOCAL_ARRAY
 ;  Allocates an array element area in the heap, and clears it filling it
-;  with 0 bytes
+;  with data whose pointer (PTR) is in the stack
 ;
 ; Parameters
 ;  HL = Offset to be added to IX => HL = IX + HL
@@ -99,12 +99,15 @@ __ALLOC_LOCAL_ARRAY_WITH_BOUNDS2:
     ld (hl), e
     inc hl
     ld (hl), d
-    pop de
+    pop de   ;; PTR to ubound table
+    push bc  ;; puts ret address back
+    ld a, d
+    or e
+    ret z    ;; if PTR for UBound is 0, it's not used
     inc hl
     ld (hl), e
     inc hl
     ld (hl), d
-    push bc
     ret
 
 

src/symbols/id_/ref/arrayref.py

@@ -39,8 +39,16 @@ def size(self):
 
     @property
     def memsize(self):
-        """Total array cell + indexes size"""
-        return (2 + (2 if self.lbound_used or self.ubound_used else 0)) * TYPE.size(gl.PTR_TYPE)
+        """Total array cell + indexes size
+        The current implementation of an array is a struct with the following information:
+
+        - PTR to DIM sizes table
+        - PTR to Array DATA region
+        - PTR to LBound Tables (always required; 0 for 0 based arrays)
+        - PTR to UBound Tables (always required, even if not used)
+        """
+        ptr_size = TYPE.size(gl.PTR_TYPE)  # Size of a pointer for the selected arch
+        return ptr_size * (3 + self.ubound_used)
 
     @property
     def data_label(self) -> str: