feat[venom]: add calloca instruction

this instruction is meant to help match call-site allocations with
pallocas (inside the callee).

Author: charles-cooper

vyper/codegen/self_call.py

@@ -1,3 +1,5 @@
+import copy
+
 from vyper.codegen.core import _freshname, eval_once_check, make_setter
 from vyper.codegen.ir_node import IRnode
 from vyper.evm.address_space import MEMORY
@@ -66,7 +68,26 @@ def ir_for_self_call(stmt_expr, context):
 
     # note: dst_tuple_t != args_tuple_t
     dst_tuple_t = TupleT(tuple(func_t.argument_types))
-    args_dst = IRnode(func_t._ir_info.frame_info.frame_start, typ=dst_tuple_t, location=MEMORY)
+    if context.settings.experimental_codegen:
+        arg_items = ["multi"]
+        frame_info = func_t._ir_info.frame_info
+
+        for var in frame_info.frame_vars.values():
+            var = copy.copy(var)
+            alloca = var.alloca
+            assert alloca is not None
+            assert isinstance(var.pos, str)  # help mypy
+            if not var.pos.startswith("$palloca"):
+                continue
+            newname = var.pos.replace("$palloca", "$calloca")
+            var.pos = newname
+            irnode = var.as_ir_node()
+            irnode.passthrough_metadata["alloca"] = alloca
+            arg_items.append(irnode)
+        args_dst = IRnode.from_list(arg_items, typ=dst_tuple_t)
+    else:
+        # legacy
+        args_dst = IRnode(func_t._ir_info.frame_info.frame_start, typ=dst_tuple_t, location=MEMORY)
 
     # if one of the arguments is a self call, the argument
     # buffer could get borked. to prevent against that,

vyper/venom/README.md

@@ -221,6 +221,11 @@ Assembly can be inspected with `-f asm`, whereas an opcode view of the final byt
     out = palloca size, offset, id
     ```
   - Like the `alloca` instruction but only used for parameters of internal functions which are passed by memory.
+- `calloca`
+  - ```
+    out = calloca size, offset, id
+    ```
+  - Similar to the `calloca` instruction but only used for parameters of internal functions which are passed by memory. Used at the call-site of a call.
 - `iload`
   - ```
     out = iload offset

vyper/venom/ir_node_to_venom.py

@@ -542,6 +542,15 @@ def emit_body_blocks():
                 _alloca_table[alloca._id] = ptr
             return _alloca_table[alloca._id]
 
+        elif ir.value.startswith("$calloca"):
+            alloca = ir.passthrough_metadata["alloca"]
+            if alloca._id not in _alloca_table:
+                ptr = fn.get_basic_block().append_instruction(
+                    "calloca", alloca.offset, alloca.size, alloca._id
+                )
+                _alloca_table[alloca._id] = ptr
+            return _alloca_table[alloca._id]
+
         return symbols.get(ir.value)
     elif ir.is_literal:
         return IRLiteral(ir.value)

vyper/venom/passes/sccp/sccp.py

@@ -177,7 +177,7 @@ def _visit_phi(self, inst: IRInstruction):
 
     def _visit_expr(self, inst: IRInstruction):
         opcode = inst.opcode
-        if opcode in ["store", "alloca", "palloca"]:
+        if opcode in ["store", "alloca", "palloca", "calloca"]:
             assert inst.output is not None, "Got store/alloca without output"
             out = self._eval_from_lattice(inst.operands[0])
             self._set_lattice(inst.output, out)

vyper/venom/venom_to_assembly.py

@@ -364,7 +364,7 @@ def _generate_evm_for_instruction(
 
         if opcode in ["jmp", "djmp", "jnz", "invoke"]:
             operands = list(inst.get_non_label_operands())
-        elif opcode in ("alloca", "palloca"):
+        elif opcode in ("alloca", "palloca", "calloca"):
             offset, _size = inst.operands
             operands = [offset]
 
@@ -464,7 +464,7 @@ def _generate_evm_for_instruction(
         # Step 5: Emit the EVM instruction(s)
         if opcode in _ONE_TO_ONE_INSTRUCTIONS:
             assembly.append(opcode.upper())
-        elif opcode in ("alloca", "palloca"):
+        elif opcode in ("alloca", "palloca", "calloca"):
             pass
         elif opcode == "param":
             pass