chore(interpreter): factor out jump logic (#1146)

Author: DaniPopes

crates/interpreter/src/instructions/control.rs

@@ -1,39 +1,32 @@
-use revm_primitives::Bytes;
-
 use crate::{
     gas,
-    primitives::{Spec, U256},
+    primitives::{Bytes, Spec, U256},
     Host, InstructionResult, Interpreter, InterpreterResult,
 };
 
 pub fn jump<H: Host>(interpreter: &mut Interpreter, _host: &mut H) {
     gas!(interpreter, gas::MID);
     pop!(interpreter, dest);
-    let dest = as_usize_or_fail!(interpreter, dest, InstructionResult::InvalidJump);
-    if interpreter.contract.is_valid_jump(dest) {
-        // SAFETY: In analysis we are checking create our jump table and we do check above to be
-        // sure that jump is safe to execute.
-        interpreter.instruction_pointer =
-            unsafe { interpreter.contract.bytecode.as_ptr().add(dest) };
-    } else {
-        interpreter.instruction_result = InstructionResult::InvalidJump;
-    }
+    jump_inner(interpreter, dest);
 }
 
 pub fn jumpi<H: Host>(interpreter: &mut Interpreter, _host: &mut H) {
     gas!(interpreter, gas::HIGH);
     pop!(interpreter, dest, value);
     if value != U256::ZERO {
-        let dest = as_usize_or_fail!(interpreter, dest, InstructionResult::InvalidJump);
-        if interpreter.contract.is_valid_jump(dest) {
-            // SAFETY: In analysis we are checking if jump is valid destination and
-            // this `if` makes this unsafe block safe.
-            interpreter.instruction_pointer =
-                unsafe { interpreter.contract.bytecode.as_ptr().add(dest) };
-        } else {
-            interpreter.instruction_result = InstructionResult::InvalidJump
-        }
+        jump_inner(interpreter, dest);
+    }
+}
+
+#[inline(always)]
+fn jump_inner(interpreter: &mut Interpreter, dest: U256) {
+    let dest = as_usize_or_fail!(interpreter, dest, InstructionResult::InvalidJump);
+    if !interpreter.contract.is_valid_jump(dest) {
+        interpreter.instruction_result = InstructionResult::InvalidJump;
+        return;
     }
+    // SAFETY: `is_valid_jump` ensures that `dest` is in bounds.
+    interpreter.instruction_pointer = unsafe { interpreter.contract.bytecode.as_ptr().add(dest) };
 }
 
 pub fn jumpdest<H: Host>(interpreter: &mut Interpreter, _host: &mut H) {