fix[codegen]: order of eval for some builtins

tests/functional/builtins/codegen/test_extract32.py

@@ -1,7 +1,6 @@
 import pytest
 
 from vyper.evm.opcodes import version_check
-from vyper.exceptions import CompilerPanic
 
 
 @pytest.mark.parametrize("location", ["storage", "transient"])
@@ -101,8 +100,6 @@ def foq(inp: Bytes[32]) -> address:
         c.foq(b"crow" * 8)
 
 
-# to fix in future release
-@pytest.mark.xfail(raises=CompilerPanic, reason="risky overlap")
 def test_extract32_order_of_eval(get_contract):
     extract32_code = """
 var:DynArray[Bytes[96], 1]
@@ -123,8 +120,6 @@ def foo() -> bytes32:
     assert c.foo() == b"defghijklmnopqrstuvwxyz123456789"
 
 
-# to fix in future release
-@pytest.mark.xfail(raises=CompilerPanic, reason="risky overlap")
 def test_extract32_order_of_eval_extcall(get_contract):
     slice_code = """
 var:DynArray[Bytes[96], 1]

tests/functional/builtins/codegen/test_slice.py

@@ -5,7 +5,7 @@
 from vyper.compiler import compile_code
 from vyper.compiler.settings import OptimizationLevel, Settings
 from vyper.evm.opcodes import version_check
-from vyper.exceptions import ArgumentException, CompilerPanic, TypeMismatch
+from vyper.exceptions import ArgumentException, TypeMismatch
 
 _fun_bytes32_bounds = [(0, 32), (3, 29), (27, 5), (0, 5), (5, 3), (30, 2)]
 
@@ -564,8 +564,6 @@ def foo(cs: String[64]) -> uint256:
     assert c.foo(arg) == 1
 
 
-# to fix in future release
-@pytest.mark.xfail(raises=CompilerPanic, reason="risky overlap")
 def test_slice_order_of_eval(get_contract):
     slice_code = """
 var:DynArray[Bytes[96], 1]
@@ -589,8 +587,6 @@ def foo() -> Bytes[96]:
     assert c.foo() == b"defghijklmnopqrstuvwxyz123456789"
 
 
-# to fix in future release
-@pytest.mark.xfail(raises=CompilerPanic, reason="risky overlap")
 def test_slice_order_of_eval2(get_contract):
     slice_code = """
 var:DynArray[Bytes[96], 1]

vyper/builtins/functions.py

@@ -21,6 +21,7 @@
     clamp_basetype,
     clamp_nonzero,
     copy_bytes,
+    create_memory_copy,
     dummy_node_for_type,
     ensure_eval_once,
     ensure_in_memory,
@@ -357,9 +358,8 @@ def build_IR(self, expr, args, kwargs, context):
             # copy_bytes works on pointers.
             assert is_bytes32, src
             src = ensure_in_memory(src, context)
-
-        if potential_overlap(src, start) or potential_overlap(src, length):
-            raise CompilerPanic("risky overlap")
+        elif potential_overlap(src, start) or potential_overlap(src, length):
+            src = create_memory_copy(src, context)
 
         with src.cache_when_complex("src") as (b1, src), start.cache_when_complex("start") as (
             b2,
@@ -867,7 +867,7 @@ def build_IR(self, expr, args, kwargs, context):
         ret_type = kwargs["output_type"]
 
         if potential_overlap(bytez, index):
-            raise CompilerPanic("risky overlap")
+            bytez = create_memory_copy(bytez, context)
 
         def finalize(ret):
             annotation = "extract32"

vyper/codegen/core.py

@@ -1103,6 +1103,14 @@ def ensure_in_memory(ir_var, context):
     return IRnode.from_list(["seq", do_copy, buf], typ=typ, location=MEMORY)
 
 
+# TODO: refactor ensure_in_memory to use this function
+def create_memory_copy(ir_var, context):
+    typ = ir_var.typ
+    buf = context.new_internal_variable(typ)
+    do_copy = make_setter(buf, ir_var)
+    return IRnode.from_list(["seq", do_copy, buf], typ=typ, location=MEMORY)
+
+
 def eval_seq(ir_node):
     """Tries to find the "return" value of a `seq` statement, in order so
     that the value can be known without possibly evaluating side effects