feat: allow vm2 tracers to stop execution (#3183)

Makes validation tracer nicer to implement.

Cargo.toml

@@ -240,7 +240,7 @@ zk_evm_1_4_1 = { package = "zk_evm", version = "0.141" }
 zk_evm_1_5_0 = { package = "zk_evm", version = "=0.150.7" }
 
 # New VM; pinned to a specific commit because of instability
-zksync_vm2 = { git = "https://github.com/matter-labs/vm2.git", rev = "df5bec3d04d64d434f9b0ccb285ba4681008f7b3" }
+zksync_vm2 = { git = "https://github.com/matter-labs/vm2.git", rev = "457d8a7eea9093af9440662e33e598c13ba41633" }
 
 # Consensus dependencies.
 zksync_concurrency = "=0.5.0"

core/lib/multivm/src/versions/vm_fast/circuits_tracer.rs

@@ -1,5 +1,7 @@
 use circuit_sequencer_api_1_5_0::{geometry_config::get_geometry_config, toolset::GeometryConfig};
-use zksync_vm2::interface::{CycleStats, GlobalStateInterface, Opcode, OpcodeType, Tracer};
+use zksync_vm2::interface::{
+    CycleStats, GlobalStateInterface, Opcode, OpcodeType, ShouldStop, Tracer,
+};
 use zksync_vm_interface::CircuitStatistic;
 
 use crate::vm_latest::tracers::circuits_capacity::*;
@@ -24,7 +26,10 @@ pub(super) struct CircuitsTracer {
 }
 
 impl Tracer for CircuitsTracer {
-    fn after_instruction<OP: OpcodeType, S: GlobalStateInterface>(&mut self, _: &mut S) {
+    fn after_instruction<OP: OpcodeType, S: GlobalStateInterface>(
+        &mut self,
+        _: &mut S,
+    ) -> ShouldStop {
         self.main_vm_cycles += 1;
 
         match OP::VALUE {
@@ -110,6 +115,8 @@ impl Tracer for CircuitsTracer {
                 self.ram_permutation_cycles += UMA_READ_RAM_CYCLES;
             }
         }
+
+        ShouldStop::Continue
     }
 
     fn on_extra_prover_cycles(&mut self, stats: CycleStats) {

core/lib/multivm/src/versions/vm_fast/vm.rs

@@ -212,6 +212,16 @@ impl<S: ReadStorage, Tr: Tracer + Default> Vm<S, Tr> {
                     };
                     break (ExecutionResult::Halt { reason }, true);
                 }
+                ExecutionEnd::StoppedByTracer => {
+                    break (
+                        ExecutionResult::Halt {
+                            reason: Halt::TracerCustom(
+                                "Unexpectedly stopped by tracer".to_string(),
+                            ),
+                        },
+                        false,
+                    );
+                }
             };
 
             match Hook::from_u32(hook) {