ASTI: fix address-of array-element-zero

Author: sipma

chb/app/CHVersion.py

@@ -1 +1 @@
-chbversion: str = "0.3.0-20241014"
+chbversion: str = "0.3.0-20241028"

chb/ast/ASTNode.py

@@ -1112,7 +1112,7 @@ def ctype(self, ctyper: "ASTCTyper") -> Optional["ASTTyp"]:
 
     def __str__(self) -> str:
         vol = " volatile" if self.volatile else ""
-        return "asm{}({}, {})".format(vol, self.template, self.clobbers) 
+        return "asm{}({}, {})".format(vol, self.template, self.clobbers)
 
 
 class ASTLval(ASTNode):
@@ -1396,6 +1396,10 @@ def is_no_offset(self) -> bool:
     def offset(self) -> "ASTOffset":
         raise Exception("offset property not supported for " + str(self))
 
+    @property
+    def tail_offset(self) -> "ASTOffset":
+        raise Exception("tail offset property not supported for " + str(self))
+
     @abstractmethod
     def transform(self, transformer: "ASTTransformer") -> "ASTOffset":
         ...
@@ -1419,6 +1423,10 @@ def __init__(self) -> None:
     def is_no_offset(self) -> bool:
         return True
 
+    @property
+    def tail_offset(self) -> "ASTOffset":
+        return self
+
     def accept(self, visitor: "ASTVisitor") -> None:
         visitor.visit_no_offset(self)
 
@@ -1472,6 +1480,13 @@ def compkey(self) -> int:
     def offset(self) -> "ASTOffset":
         return self._byteoffset
 
+    @property
+    def tail_offset(self) -> "ASTOffset":
+        if self.offset.is_no_offset:
+            return self
+        else:
+            return self._byteoffset.tail_offset
+
     def accept(self, visitor: "ASTVisitor") -> None:
         visitor.visit_field_offset(self)
 
@@ -1516,6 +1531,13 @@ def index_expr(self) -> "ASTExpr":
     def offset(self) -> "ASTOffset":
         return self._offset
 
+    @property
+    def tail_offset(self) -> "ASTOffset":
+        if self.offset.is_no_offset:
+            return self
+        else:
+            return self.offset.tail_offset
+
     def accept(self, visitor: "ASTVisitor") -> None:
         visitor.visit_index_offset(self)
 
@@ -1593,6 +1615,10 @@ def is_ast_constant(self) -> bool:
     def is_integer_constant(self) -> bool:
         return False
 
+    @property
+    def is_integer_constant_zero(self) -> bool:
+        return False
+
     @property
     def is_global_address(self) -> bool:
         return False
@@ -1686,6 +1712,10 @@ def __init__(
     def is_integer_constant(self) -> bool:
         return True
 
+    @property
+    def is_integer_constant_zero(self) -> bool:
+        return self.cvalue == 0
+
     @property
     def cvalue(self) -> int:
         return self._cvalue

chb/astinterface/ASTInterface.py

@@ -1377,10 +1377,39 @@ def mk_string_constant(
         return self.astree.mk_string_constant(expr, cstr, saddr)
 
     def mk_address_of(
-            self, lval: AST.ASTLval, anonymous: bool = False) -> AST.ASTAddressOf:
+            self, lval: AST.ASTLval, anonymous: bool = False) -> AST.ASTExpr:
         optexprid = -1 if anonymous else None
+        if lval.offset.tail_offset.is_index_offset:
+            indexexpr = cast(
+                AST.ASTIndexOffset, lval.offset.tail_offset).index_expr
+            if indexexpr.is_integer_constant_zero:
+                return self.mk_index_parent_start_of(lval)
+
         return self.astree.mk_address_of_expression(lval, optexprid=optexprid)
 
+    def mk_index_parent_start_of(self, lval: AST.ASTLval) -> AST.ASTStartOf:
+
+        def replace_tail(offset: AST.ASTOffset) -> AST.ASTOffset:
+            if offset.is_no_offset:
+                chklogger.logger.error("Inconsistent offset")
+                return offset
+            elif offset.is_field_offset:
+                offset = cast(AST.ASTFieldOffset, offset)
+                suboffset = replace_tail(offset.offset)
+                return self.mk_field_offset(
+                    offset.fieldname, offset.compkey, offset = suboffset)
+            else:
+                if offset.offset.is_no_offset:
+                    return offset.offset
+                else:
+                    offset = cast(AST.ASTIndexOffset, offset)
+                    suboffset = replace_tail(offset.offset)
+                    return self.mk_expr_index_offset(
+                        offset.index_expr, offset=suboffset)
+
+        lval = self.mk_lval(lval.lhost, replace_tail(lval.offset))
+        return self.mk_start_of(lval)
+
     def mk_start_of(self, lval: AST.ASTLval) -> AST.ASTStartOf:
         return self.astree.mk_start_of_expression(lval, optexprid=None)