diff --git a/slither/detectors/assembly/incorrect_return.py b/slither/detectors/assembly/incorrect_return.py
index 48ecab178..9052979ac 100644
--- a/slither/detectors/assembly/incorrect_return.py
+++ b/slither/detectors/assembly/incorrect_return.py
@@ -21,10 +21,8 @@ def _assembly_node(function: Function) -> Optional[SolidityCall]:
 
     """
 
-    for ir in function.all_slithir_operations():
-        if isinstance(ir, SolidityCall) and ir.function == SolidityFunction(
-            "return(uint256,uint256)"
-        ):
+    for ir in function.all_solidity_calls():
+        if ir.function == SolidityFunction("return(uint256,uint256)"):
             return ir
     return None
 
@@ -71,24 +69,23 @@ The function will return 6 bytes starting from offset 5, instead of returning a
         for c in self.contracts:
             for f in c.functions_and_modifiers_declared:
 
-                for node in f.nodes:
-                    if node.sons:
-                        for ir in node.internal_calls:
-                            function_called = ir.function
-                            if isinstance(function_called, Function):
-                                found = _assembly_node(function_called)
-                                if found:
-
-                                    info: DETECTOR_INFO = [
-                                        f,
-                                        " calls ",
-                                        function_called,
-                                        " which halt the execution ",
-                                        found.node,
-                                        "\n",
-                                    ]
-                                    json = self.generate_result(info)
-
-                                    results.append(json)
+                for ir in f.internal_calls:
+                    if ir.node.sons:
+                        function_called = ir.function
+                        if isinstance(function_called, Function):
+                            found = _assembly_node(function_called)
+                            if found:
+
+                                info: DETECTOR_INFO = [
+                                    f,
+                                    " calls ",
+                                    function_called,
+                                    " which halt the execution ",
+                                    found.node,
+                                    "\n",
+                                ]
+                                json = self.generate_result(info)
+
+                                results.append(json)
 
         return results
diff --git a/slither/detectors/assembly/return_instead_of_leave.py b/slither/detectors/assembly/return_instead_of_leave.py
index a1ad9c87e..603705974 100644
--- a/slither/detectors/assembly/return_instead_of_leave.py
+++ b/slither/detectors/assembly/return_instead_of_leave.py
@@ -6,7 +6,6 @@ from slither.detectors.abstract_detector import (
     DetectorClassification,
     DETECTOR_INFO,
 )
-from slither.slithir.operations import SolidityCall
 from slither.utils.output import Output
 
 
@@ -42,15 +41,12 @@ The function will halt the execution, instead of returning a two uint."""
     def _check_function(self, f: Function) -> List[Output]:
         results: List[Output] = []
 
-        for node in f.nodes:
-            for ir in node.irs:
-                if isinstance(ir, SolidityCall) and ir.function == SolidityFunction(
-                    "return(uint256,uint256)"
-                ):
-                    info: DETECTOR_INFO = [f, " contains an incorrect call to return: ", node, "\n"]
-                    json = self.generate_result(info)
+        for ir in f.solidity_calls:
+            if ir.function == SolidityFunction("return(uint256,uint256)"):
+                info: DETECTOR_INFO = [f, " contains an incorrect call to return: ", ir.node, "\n"]
+                json = self.generate_result(info)
 
-                    results.append(json)
+                results.append(json)
         return results
 
     def _detect(self) -> List[Output]:
diff --git a/slither/detectors/compiler_bugs/array_by_reference.py b/slither/detectors/compiler_bugs/array_by_reference.py
index 47e2af581..e4dde4360 100644
--- a/slither/detectors/compiler_bugs/array_by_reference.py
+++ b/slither/detectors/compiler_bugs/array_by_reference.py
@@ -13,8 +13,6 @@ from slither.detectors.abstract_detector import (
 from slither.core.solidity_types.array_type import ArrayType
 from slither.core.variables.state_variable import StateVariable
 from slither.core.variables.local_variable import LocalVariable
-from slither.slithir.operations.high_level_call import HighLevelCall
-from slither.slithir.operations.internal_call import InternalCall
 from slither.core.cfg.node import Node
 from slither.core.declarations.contract import Contract
 from slither.core.declarations.function_contract import FunctionContract
@@ -117,37 +115,26 @@ As a result, Bob's usage of the contract is incorrect."""
         # pylint: disable=too-many-nested-blocks
         for contract in contracts:
             for function in contract.functions_and_modifiers_declared:
-                for node in function.nodes:
+                for ir in [ir for _, ir in function.high_level_calls] + function.internal_calls:
 
-                    # If this node has no expression, skip it.
-                    if not node.expression:
+                    # Verify this references a function in our array modifying functions collection.
+                    if ir.function not in array_modifying_funcs:
                         continue
 
-                    for ir in node.irs:
-                        # Verify this is a high level call.
-                        if not isinstance(ir, (HighLevelCall, InternalCall)):
+                    # Verify one of these parameters is an array in storage.
+                    for (param, arg) in zip(ir.function.parameters, ir.arguments):
+                        # Verify this argument is a variable that is an array type.
+                        if not isinstance(arg, (StateVariable, LocalVariable)):
                             continue
-
-                        # Verify this references a function in our array modifying functions collection.
-                        if ir.function not in array_modifying_funcs:
+                        if not isinstance(arg.type, ArrayType):
                             continue
 
-                        # Verify one of these parameters is an array in storage.
-                        for (param, arg) in zip(ir.function.parameters, ir.arguments):
-                            # Verify this argument is a variable that is an array type.
-                            if not isinstance(arg, (StateVariable, LocalVariable)):
-                                continue
-                            if not isinstance(arg.type, ArrayType):
-                                continue
-
-                            # If it is a state variable OR a local variable referencing storage, we add it to the list.
-                            if (
-                                isinstance(arg, StateVariable)
-                                or (isinstance(arg, LocalVariable) and arg.location == "storage")
-                            ) and (
-                                isinstance(param.type, ArrayType) and param.location != "storage"
-                            ):
-                                results.append((node, arg, ir.function))
+                        # If it is a state variable OR a local variable referencing storage, we add it to the list.
+                        if (
+                            isinstance(arg, StateVariable)
+                            or (isinstance(arg, LocalVariable) and arg.location == "storage")
+                        ) and (isinstance(param.type, ArrayType) and param.location != "storage"):
+                            results.append((ir.node, arg, ir.function))
         return results
 
     def _detect(self) -> List[Output]:
diff --git a/slither/detectors/erc/erc20/arbitrary_send_erc20.py b/slither/detectors/erc/erc20/arbitrary_send_erc20.py
index 046b53ccb..4dc1f8db5 100644
--- a/slither/detectors/erc/erc20/arbitrary_send_erc20.py
+++ b/slither/detectors/erc/erc20/arbitrary_send_erc20.py
@@ -3,7 +3,7 @@ from typing import List
 from slither.analyses.data_dependency.data_dependency import is_dependent
 from slither.core.cfg.node import Node
 from slither.core.compilation_unit import SlitherCompilationUnit
-from slither.core.declarations import Contract, Function, SolidityVariableComposed
+from slither.core.declarations import Contract, Function, SolidityVariableComposed, FunctionContract
 from slither.core.declarations.solidity_variables import SolidityVariable
 from slither.slithir.operations import HighLevelCall, LibraryCall
 
@@ -44,51 +44,50 @@ class ArbitrarySendErc20:
                     "permit(address,address,uint256,uint256,uint8,bytes32,bytes32)"
                     in all_high_level_calls
                 ):
-                    ArbitrarySendErc20._arbitrary_from(f.nodes, self._permit_results)
+                    ArbitrarySendErc20._arbitrary_from(f, self._permit_results)
                 else:
-                    ArbitrarySendErc20._arbitrary_from(f.nodes, self._no_permit_results)
+                    ArbitrarySendErc20._arbitrary_from(f, self._no_permit_results)
 
     @staticmethod
-    def _arbitrary_from(nodes: List[Node], results: List[Node]) -> None:
+    def _arbitrary_from(function: FunctionContract, results: List[Node]) -> None:
         """Finds instances of (safe)transferFrom that do not use msg.sender or address(this) as from parameter."""
-        for node in nodes:
-            for ir in node.irs:
-                if (
-                    isinstance(ir, HighLevelCall)
-                    and isinstance(ir.function, Function)
-                    and ir.function.solidity_signature == "transferFrom(address,address,uint256)"
-                    and not (
-                        is_dependent(
-                            ir.arguments[0],
-                            SolidityVariableComposed("msg.sender"),
-                            node,
-                        )
-                        or is_dependent(
-                            ir.arguments[0],
-                            SolidityVariable("this"),
-                            node,
-                        )
+        for _, ir in function.high_level_calls:
+            if (
+                isinstance(ir, LibraryCall)
+                and ir.function.solidity_signature
+                == "safeTransferFrom(address,address,address,uint256)"
+                and not (
+                    is_dependent(
+                        ir.arguments[1],
+                        SolidityVariableComposed("msg.sender"),
+                        ir.node,
                     )
-                ):
-                    results.append(ir.node)
-                elif (
-                    isinstance(ir, LibraryCall)
-                    and ir.function.solidity_signature
-                    == "safeTransferFrom(address,address,address,uint256)"
-                    and not (
-                        is_dependent(
-                            ir.arguments[1],
-                            SolidityVariableComposed("msg.sender"),
-                            node,
-                        )
-                        or is_dependent(
-                            ir.arguments[1],
-                            SolidityVariable("this"),
-                            node,
-                        )
+                    or is_dependent(
+                        ir.arguments[1],
+                        SolidityVariable("this"),
+                        ir.node,
                     )
-                ):
-                    results.append(ir.node)
+                )
+            ):
+                results.append(ir.node)
+            elif (
+                isinstance(ir, HighLevelCall)
+                and isinstance(ir.function, Function)
+                and ir.function.solidity_signature == "transferFrom(address,address,uint256)"
+                and not (
+                    is_dependent(
+                        ir.arguments[0],
+                        SolidityVariableComposed("msg.sender"),
+                        ir.node,
+                    )
+                    or is_dependent(
+                        ir.arguments[0],
+                        SolidityVariable("this"),
+                        ir.node,
+                    )
+                )
+            ):
+                results.append(ir.node)
 
     def detect(self) -> None:
         """Detect transfers that use arbitrary `from` parameter."""
diff --git a/slither/detectors/functions/external_function.py b/slither/detectors/functions/external_function.py
index 5858c2baf..c59fe4492 100644
--- a/slither/detectors/functions/external_function.py
+++ b/slither/detectors/functions/external_function.py
@@ -13,8 +13,7 @@ from slither.detectors.abstract_detector import (
     make_solc_versions,
 )
 from slither.formatters.functions.external_function import custom_format
-from slither.slithir.operations import InternalCall, InternalDynamicCall
-from slither.slithir.operations import SolidityCall
+from slither.slithir.operations import InternalDynamicCall
 from slither.utils.output import Output
 
 
@@ -55,11 +54,11 @@ class ExternalFunction(AbstractDetector):
         for func in contract.all_functions_called:
             if not isinstance(func, Function):
                 continue
-            # Loop through all nodes in the function, add all calls to a list.
-            for node in func.nodes:
-                for ir in node.irs:
-                    if isinstance(ir, (InternalCall, SolidityCall)):
-                        result.append(ir.function)
+
+            # Loop through all internal and solidity calls in the function, add them to a list.
+            for ir in func.internal_calls + func.solidity_calls:
+                result.append(ir.function)
+
         return result
 
     @staticmethod
diff --git a/slither/detectors/operations/encode_packed.py b/slither/detectors/operations/encode_packed.py
index ea7b094df..b661ddcd7 100644
--- a/slither/detectors/operations/encode_packed.py
+++ b/slither/detectors/operations/encode_packed.py
@@ -3,14 +3,14 @@ Module detecting usage of more than one dynamic type in abi.encodePacked() argum
 """
 
 from slither.detectors.abstract_detector import AbstractDetector, DetectorClassification
-from slither.core.declarations.solidity_variables import SolidityFunction
-from slither.slithir.operations import SolidityCall
+from slither.core.declarations import Contract, SolidityFunction
+from slither.core.variables import Variable
 from slither.analyses.data_dependency.data_dependency import is_tainted
 from slither.core.solidity_types import ElementaryType
 from slither.core.solidity_types import ArrayType
 
 
-def _is_dynamic_type(arg):
+def _is_dynamic_type(arg: Variable):
     """
     Args:
         arg (function argument)
@@ -25,7 +25,7 @@ def _is_dynamic_type(arg):
     return False
 
 
-def _detect_abi_encodePacked_collision(contract):
+def _detect_abi_encodePacked_collision(contract: Contract):
     """
     Args:
         contract (Contract)
@@ -35,22 +35,19 @@ def _detect_abi_encodePacked_collision(contract):
     ret = []
     # pylint: disable=too-many-nested-blocks
     for f in contract.functions_and_modifiers_declared:
-        for n in f.nodes:
-            for ir in n.irs:
-                if isinstance(ir, SolidityCall) and ir.function == SolidityFunction(
-                    "abi.encodePacked()"
-                ):
-                    dynamic_type_count = 0
-                    for arg in ir.arguments:
-                        if is_tainted(arg, contract) and _is_dynamic_type(arg):
-                            dynamic_type_count += 1
-                        elif dynamic_type_count > 1:
-                            ret.append((f, n))
-                            dynamic_type_count = 0
-                        else:
-                            dynamic_type_count = 0
-                    if dynamic_type_count > 1:
-                        ret.append((f, n))
+        for ir in f.solidity_calls:
+            if ir.function == SolidityFunction("abi.encodePacked()"):
+                dynamic_type_count = 0
+                for arg in ir.arguments:
+                    if is_tainted(arg, contract) and _is_dynamic_type(arg):
+                        dynamic_type_count += 1
+                    elif dynamic_type_count > 1:
+                        ret.append((f, ir.node))
+                        dynamic_type_count = 0
+                    else:
+                        dynamic_type_count = 0
+                if dynamic_type_count > 1:
+                    ret.append((f, ir.node))
     return ret
 
 
diff --git a/slither/detectors/operations/low_level_calls.py b/slither/detectors/operations/low_level_calls.py
index 463c74875..4925fc466 100644
--- a/slither/detectors/operations/low_level_calls.py
+++ b/slither/detectors/operations/low_level_calls.py
@@ -44,10 +44,9 @@ class LowLevelCalls(AbstractDetector):
     ) -> List[Tuple[FunctionContract, List[Node]]]:
         ret = []
         for f in [f for f in contract.functions if contract == f.contract_declarer]:
-            nodes = f.nodes
-            assembly_nodes = [n for n in nodes if self._contains_low_level_calls(n)]
-            if assembly_nodes:
-                ret.append((f, assembly_nodes))
+            low_level_nodes = [ir.node for ir in f.low_level_calls]
+            if low_level_nodes:
+                ret.append((f, low_level_nodes))
         return ret
 
     def _detect(self) -> List[Output]:
diff --git a/slither/detectors/statements/assert_state_change.py b/slither/detectors/statements/assert_state_change.py
index 8a04f11e0..d70495365 100644
--- a/slither/detectors/statements/assert_state_change.py
+++ b/slither/detectors/statements/assert_state_change.py
@@ -30,22 +30,22 @@ def detect_assert_state_change(
 
     # Loop for each function and modifier.
     for function in contract.functions_declared + list(contract.modifiers_declared):
-        for node in function.nodes:
+        for ir_call in function.internal_calls:
             # Detect assert() calls
-            if any(ir.function.name == "assert(bool)" for ir in node.internal_calls) and (
+            if ir_call.function.name == "assert(bool)" and (
                 # Detect direct changes to state
-                node.state_variables_written
+                ir_call.node.state_variables_written
                 or
                 # Detect changes to state via function calls
                 any(
                     ir
-                    for ir in node.irs
+                    for ir in ir_call.node.irs
                     if isinstance(ir, InternalCall)
                     and ir.function
                     and ir.function.state_variables_written
                 )
             ):
-                results.append((function, node))
+                results.append((function, ir_call.node))
 
     # Return the resulting set of nodes
     return results
diff --git a/slither/detectors/statements/controlled_delegatecall.py b/slither/detectors/statements/controlled_delegatecall.py
index 32e59d6eb..bf78b3bf9 100644
--- a/slither/detectors/statements/controlled_delegatecall.py
+++ b/slither/detectors/statements/controlled_delegatecall.py
@@ -8,20 +8,18 @@ from slither.detectors.abstract_detector import (
     DetectorClassification,
     DETECTOR_INFO,
 )
-from slither.slithir.operations import LowLevelCall
 from slither.utils.output import Output
 
 
 def controlled_delegatecall(function: FunctionContract) -> List[Node]:
     ret = []
-    for node in function.nodes:
-        for ir in node.irs:
-            if isinstance(ir, LowLevelCall) and ir.function_name in [
-                "delegatecall",
-                "callcode",
-            ]:
-                if is_tainted(ir.destination, function.contract):
-                    ret.append(node)
+    for ir in function.low_level_calls:
+        if ir.function_name in [
+            "delegatecall",
+            "callcode",
+        ]:
+            if is_tainted(ir.destination, function.contract):
+                ret.append(ir.node)
     return ret
 
 
diff --git a/slither/detectors/statements/return_bomb.py b/slither/detectors/statements/return_bomb.py
index 8b6cd07a2..6d7052cf4 100644
--- a/slither/detectors/statements/return_bomb.py
+++ b/slither/detectors/statements/return_bomb.py
@@ -9,7 +9,7 @@ from slither.detectors.abstract_detector import (
     DetectorClassification,
     DETECTOR_INFO,
 )
-from slither.slithir.operations import LowLevelCall, HighLevelCall
+from slither.slithir.operations import HighLevelCall
 from slither.analyses.data_dependency.data_dependency import is_tainted
 from slither.utils.output import Output
 
@@ -71,34 +71,31 @@ Callee unexpectedly makes the caller OOG.
 
     def get_nodes_for_function(self, function: Function, contract: Contract) -> List[Node]:
         nodes = []
-        for node in function.nodes:
-            for ir in node.irs:
-                if isinstance(ir, (HighLevelCall, LowLevelCall)):
-                    if not is_tainted(ir.destination, contract):  # type:ignore
-                        # Only interested if the target address is controlled/tainted
-                        continue
-
-                    if isinstance(ir, HighLevelCall) and isinstance(ir.function, Function):
-                        # in normal highlevel calls return bombs are _possible_
-                        # if the return type is dynamic and the caller tries to copy and decode large data
-                        has_dyn = False
-                        if ir.function.return_type:
-                            has_dyn = any(
-                                self.is_dynamic_type(ty) for ty in ir.function.return_type
-                            )
-
-                        if not has_dyn:
-                            continue
-
-                    # If a gas budget was specified then the
-                    # user may not know about the return bomb
-                    if ir.call_gas is None:
-                        # if a gas budget was NOT specified then the caller
-                        # may already suspect the call may spend all gas?
-                        continue
-
-                    nodes.append(node)
-                # TODO: check that there is some state change after the call
+
+        for ir in [ir for _, ir in function.high_level_calls] + function.low_level_calls:
+            if not is_tainted(ir.destination, contract):  # type:ignore
+                # Only interested if the target address is controlled/tainted
+                continue
+
+            if isinstance(ir, HighLevelCall) and isinstance(ir.function, Function):
+                # in normal highlevel calls return bombs are _possible_
+                # if the return type is dynamic and the caller tries to copy and decode large data
+                has_dyn = False
+                if ir.function.return_type:
+                    has_dyn = any(self.is_dynamic_type(ty) for ty in ir.function.return_type)
+
+                if not has_dyn:
+                    continue
+
+            # If a gas budget was specified then the
+            # user may not know about the return bomb
+            if ir.call_gas is None:
+                # if a gas budget was NOT specified then the caller
+                # may already suspect the call may spend all gas?
+                continue
+
+            nodes.append(ir.node)
+        # TODO: check that there is some state change after the call
 
         return nodes
 
diff --git a/slither/detectors/statements/unprotected_upgradeable.py b/slither/detectors/statements/unprotected_upgradeable.py
index 681057749..aeb785da3 100644
--- a/slither/detectors/statements/unprotected_upgradeable.py
+++ b/slither/detectors/statements/unprotected_upgradeable.py
@@ -7,23 +7,28 @@ from slither.detectors.abstract_detector import (
     DetectorClassification,
     DETECTOR_INFO,
 )
-from slither.slithir.operations import LowLevelCall, SolidityCall
 from slither.utils.output import Output
 
 
 def _can_be_destroyed(contract: Contract) -> List[Function]:
     targets = []
     for f in contract.functions_entry_points:
-        for ir in f.all_slithir_operations():
-            if (
-                isinstance(ir, LowLevelCall) and ir.function_name in ["delegatecall", "codecall"]
-            ) or (
-                isinstance(ir, SolidityCall)
-                and ir.function
-                in [SolidityFunction("suicide(address)"), SolidityFunction("selfdestruct(address)")]
-            ):
+        found = False
+        for ir in f.all_low_level_calls():
+            if ir.function_name in ["delegatecall", "codecall"]:
                 targets.append(f)
+                found = True
                 break
+
+        if not found:
+            for ir in f.all_solidity_calls():
+                if ir.function in [
+                    SolidityFunction("suicide(address)"),
+                    SolidityFunction("selfdestruct(address)"),
+                ]:
+                    targets.append(f)
+                    break
+
     return targets
 
 
diff --git a/slither/detectors/variables/var_read_using_this.py b/slither/detectors/variables/var_read_using_this.py
index 537eecf8a..1e4787e36 100644
--- a/slither/detectors/variables/var_read_using_this.py
+++ b/slither/detectors/variables/var_read_using_this.py
@@ -7,7 +7,6 @@ from slither.detectors.abstract_detector import (
     DetectorClassification,
     DETECTOR_INFO,
 )
-from slither.slithir.operations.high_level_call import HighLevelCall
 from slither.utils.output import Output
 
 
@@ -54,13 +53,11 @@ contract C {
     @staticmethod
     def _detect_var_read_using_this(func: Function) -> List[Node]:
         results: List[Node] = []
-        for node in func.nodes:
-            for ir in node.irs:
-                if isinstance(ir, HighLevelCall):
-                    if (
-                        ir.destination == SolidityVariable("this")
-                        and ir.is_static_call()
-                        and ir.function.visibility == "public"
-                    ):
-                        results.append(node)
+        for _, ir in func.high_level_calls:
+            if (
+                ir.destination == SolidityVariable("this")
+                and ir.is_static_call()
+                and ir.function.visibility == "public"
+            ):
+                results.append(ir.node)
         return sorted(results, key=lambda x: x.node_id)