fix[codegen]: fix some hardcoded references to STORAGE location (vy…

…perlang#4015)

fix some hardcoded references to `STORAGE` when `TRANSIENT` is also
possible. these are not breaking changes semantically, but should enable
the correct optimization codepath for transient storage. this commit
also results in better codepaths taken for the IMMUTABLES location
(`iload`/`istore`), resulting in smaller bytecode sometimes for
constructors.

---------

Co-authored-by: Charles Cooper <cooper.charles.m@gmail.com>

.github/workflows/test.yml

@@ -91,6 +91,12 @@ jobs:
           - evm-version: paris
           - evm-version: shanghai
 
+          # test pre-cancun with opt-codesize and opt-none
+          - evm-version: shanghai
+            opt-mode: none
+          - evm-version: shanghai
+            opt-mode: codesize
+
           # test py-evm
           - evm-backend: py-evm
             evm-version: shanghai

vyper/ast/nodes.pyi

@@ -234,6 +234,7 @@ class VariableDecl(VyperNode):
     is_constant: bool = ...
     is_public: bool = ...
     is_immutable: bool = ...
+    is_transient: bool = ...
     _expanded_getter: FunctionDef = ...
 
 class AugAssign(VyperNode):

vyper/codegen/core.py

@@ -8,6 +8,7 @@
     STORAGE,
     TRANSIENT,
     AddrSpace,
+    legal_in_staticcall,
 )
 from vyper.evm.opcodes import version_check
 from vyper.exceptions import CompilerPanic, TypeCheckFailure, TypeMismatch
@@ -136,6 +137,14 @@ def address_space_to_data_location(s: AddrSpace) -> DataLocation:
     raise CompilerPanic("unreachable!")  # pragma: nocover
 
 
+def writeable(context, ir_node):
+    assert ir_node.is_pointer  # sanity check
+
+    if context.is_constant() and not legal_in_staticcall(ir_node.location):
+        return False
+    return ir_node.mutable
+
+
 # Copy byte array word-for-word (including layout)
 # TODO make this a private function
 def make_byte_array_copier(dst, src):
@@ -150,12 +159,9 @@ def make_byte_array_copier(dst, src):
         return STORE(dst, 0)
 
     with src.cache_when_complex("src") as (b1, src):
-        has_storage = STORAGE in (src.location, dst.location)
-        is_memory_copy = dst.location == src.location == MEMORY
-        batch_uses_identity = is_memory_copy and not version_check(begin="cancun")
-        if src.typ.maxlen <= 32 and (has_storage or batch_uses_identity):
+        if src.typ.maxlen <= 32 and not copy_opcode_available(dst, src):
+            # if there is no batch copy opcode available,
             # it's cheaper to run two load/stores instead of copy_bytes
-
             ret = ["seq"]
             # store length word
             len_ = get_bytearray_length(src)
@@ -914,6 +920,15 @@ def make_setter(left, right):
     return _complex_make_setter(left, right)
 
 
+# locations with no dedicated copy opcode
+# (i.e. storage and transient storage)
+def copy_opcode_available(left, right):
+    if left.location == MEMORY and right.location == MEMORY:
+        return version_check(begin="cancun")
+
+    return left.location == MEMORY and right.location.has_copy_opcode
+
+
 def _complex_make_setter(left, right):
     if right.value == "~empty" and left.location == MEMORY:
         # optimized memzero
@@ -935,8 +950,10 @@ def _complex_make_setter(left, right):
         assert left.encoding == Encoding.VYPER
         len_ = left.typ.memory_bytes_required
 
-        has_storage = STORAGE in (left.location, right.location)
-        if has_storage:
+        # special logic for identity precompile (pre-cancun) in the else branch
+        mem2mem = left.location == right.location == MEMORY
+
+        if not copy_opcode_available(left, right) and not mem2mem:
             if _opt_codesize():
                 # assuming PUSH2, a single sstore(dst (sload src)) is 8 bytes,
                 # sstore(add (dst ofst), (sload (add (src ofst)))) is 16 bytes,
@@ -983,7 +1000,7 @@ def _complex_make_setter(left, right):
                     base_unroll_cost + (nth_word_cost * (n_words - 1)) >= identity_base_cost
                 )
 
-            # calldata to memory, code to memory, cancun, or codesize -
+            # calldata to memory, code to memory, cancun, or opt-codesize -
             # batch copy is always better.
             else:
                 should_batch_copy = True

vyper/codegen/stmt.py

@@ -14,10 +14,11 @@
     get_type_for_exact_size,
     make_setter,
     wrap_value_for_external_return,
+    writeable,
 )
 from vyper.codegen.expr import Expr
 from vyper.codegen.return_ import make_return_stmt
-from vyper.evm.address_space import MEMORY, STORAGE
+from vyper.evm.address_space import MEMORY
 from vyper.exceptions import CodegenPanic, StructureException, TypeCheckFailure, tag_exceptions
 from vyper.semantics.types import DArrayT
 from vyper.semantics.types.shortcuts import UINT256_T
@@ -312,18 +313,18 @@ def parse_Return(self):
     def _get_target(self, target):
         _dbg_expr = target
 
-        if isinstance(target, vy_ast.Name) and target.id in self.context.forvars:
+        if isinstance(target, vy_ast.Name) and target.id in self.context.forvars:  # pragma: nocover
             raise TypeCheckFailure(f"Failed constancy check\n{_dbg_expr}")
 
         if isinstance(target, vy_ast.Tuple):
             target = Expr(target, self.context).ir_node
-            for node in target.args:
-                if (node.location == STORAGE and self.context.is_constant()) or not node.mutable:
-                    raise TypeCheckFailure(f"Failed constancy check\n{_dbg_expr}")
+            items = target.args
+            if any(not writeable(self.context, item) for item in items):  # pragma: nocover
+                raise TypeCheckFailure(f"Failed constancy check\n{_dbg_expr}")
             return target
 
         target = Expr.parse_pointer_expr(target, self.context)
-        if (target.location == STORAGE and self.context.is_constant()) or not target.mutable:
+        if not writeable(self.context, target):  # pragma: nocover
             raise TypeCheckFailure(f"Failed constancy check\n{_dbg_expr}")
         return target
 

vyper/evm/address_space.py

@@ -20,18 +20,25 @@ class AddrSpace:
         load_op: the opcode for loading a word from this address space
         store_op: the opcode for storing a word to this address space
             (an address space is read-only if store_op is None)
+        copy_op: the opcode for batch-copying from this address space
+            to memory
     """
 
     name: str
     word_scale: int
     load_op: str
     # TODO maybe make positional instead of defaulting to None
     store_op: Optional[str] = None
+    copy_op: Optional[str] = None
 
     @property
     def word_addressable(self) -> bool:
         return self.word_scale == 1
 
+    @property
+    def has_copy_opcode(self):
+        return self.copy_op is not None
+
 
 # alternative:
 # class Memory(AddrSpace):
@@ -42,13 +49,17 @@ def word_addressable(self) -> bool:
 #
 # MEMORY = Memory()
 
-MEMORY = AddrSpace("memory", 32, "mload", "mstore")
+MEMORY = AddrSpace("memory", 32, "mload", "mstore", "mcopy")
 STORAGE = AddrSpace("storage", 1, "sload", "sstore")
 TRANSIENT = AddrSpace("transient", 1, "tload", "tstore")
-CALLDATA = AddrSpace("calldata", 32, "calldataload")
+CALLDATA = AddrSpace("calldata", 32, "calldataload", None, "calldatacopy")
 # immutables address space: "immutables" section of memory
 # which is read-write in deploy code but then gets turned into
 # the "data" section of the runtime code
 IMMUTABLES = AddrSpace("immutables", 32, "iload", "istore")
 # data addrspace: "data" section of runtime code, read-only.
-DATA = AddrSpace("data", 32, "dload")
+DATA = AddrSpace("data", 32, "dload", None, "dloadbytes")
+
+
+def legal_in_staticcall(location: AddrSpace):
+    return location not in (STORAGE, TRANSIENT)

vyper/semantics/analysis/module.py

@@ -621,13 +621,6 @@ def visit_VariableDecl(self, node):
         assert isinstance(node.target, vy_ast.Name)
         name = node.target.id
 
-        if node.is_public:
-            # generate function type and add to metadata
-            # we need this when building the public getter
-            func_t = ContractFunctionT.getter_from_VariableDecl(node)
-            node._metadata["getter_type"] = func_t
-            self._add_exposed_function(func_t, node)
-
         # TODO: move this check to local analysis
         if node.is_immutable:
             # mutability is checked automatically preventing assignment
@@ -648,7 +641,7 @@ def visit_VariableDecl(self, node):
                 )
                 raise ImmutableViolation(message, node)
 
-        data_loc = (
+        location = (
             DataLocation.CODE
             if node.is_immutable
             else DataLocation.UNSET
@@ -666,21 +659,28 @@ def visit_VariableDecl(self, node):
             else Modifiability.MODIFIABLE
         )
 
-        type_ = type_from_annotation(node.annotation, data_loc)
+        type_ = type_from_annotation(node.annotation, location)
 
         if node.is_transient and not version_check(begin="cancun"):
             raise EvmVersionException("`transient` is not available pre-cancun", node.annotation)
 
         var_info = VarInfo(
             type_,
             decl_node=node,
-            location=data_loc,
+            location=location,
             modifiability=modifiability,
             is_public=node.is_public,
         )
         node.target._metadata["varinfo"] = var_info  # TODO maybe put this in the global namespace
         node._metadata["type"] = type_
 
+        if node.is_public:
+            # generate function type and add to metadata
+            # we need this when building the public getter
+            func_t = ContractFunctionT.getter_from_VariableDecl(node)
+            node._metadata["getter_type"] = func_t
+            self._add_exposed_function(func_t, node)
+
         def _finalize():
             # add the variable name to `self` namespace if the variable is either
             # 1. a public constant or immutable; or

vyper/semantics/types/function.py

@@ -460,7 +460,10 @@ def getter_from_VariableDecl(cls, node: vy_ast.VariableDecl) -> "ContractFunctio
         """
         if not node.is_public:
             raise CompilerPanic("getter generated for non-public function")
-        type_ = type_from_annotation(node.annotation, DataLocation.STORAGE)
+
+        # calculated by caller (ModuleAnalyzer.visit_VariableDecl)
+        type_ = node.target._metadata["varinfo"].typ
+
         arguments, return_type = type_.getter_signature
         args = []
         for i, item in enumerate(arguments):

vyper/semantics/types/subscriptable.py

@@ -46,7 +46,7 @@ class HashMapT(_SubscriptableT):
 
     _equality_attrs = ("key_type", "value_type")
 
-    # disallow everything but storage
+    # disallow everything but storage or transient
     _invalid_locations = (
         DataLocation.UNSET,
         DataLocation.CALLDATA,
@@ -84,10 +84,11 @@ def from_annotation(cls, node: vy_ast.Subscript) -> "HashMapT":
             )
 
         k_ast, v_ast = node.slice.elements
-        key_type = type_from_annotation(k_ast, DataLocation.STORAGE)
+        key_type = type_from_annotation(k_ast)
         if not key_type._as_hashmap_key:
             raise InvalidType("can only use primitive types as HashMap key!", k_ast)
 
+        # TODO: thread through actual location - might also be TRANSIENT
         value_type = type_from_annotation(v_ast, DataLocation.STORAGE)
 
         return cls(key_type, value_type)