add a MAX_MEMORY_SIZE, in order to use Dmitry's trick

Author: TomWambsgans

crates/lean_prover/src/verify_execution.rs

@@ -71,10 +71,13 @@ pub fn verify_execution(
     let n_cycles = 1 << log_n_cycles;
 
     let public_memory = build_public_memory(public_input);
-    let public_memory_len = public_memory.len();
 
-    let log_public_memory = log2_strict_usize(public_memory_len);
-    let log_memory = log2_ceil_usize(public_memory_len + private_memory_len);
+    if log2_ceil_usize(private_memory_len + private_memory_len) > MAX_MEMORY_SIZE {
+        return Err(ProofError::InvalidProof);
+    }
+
+    let log_public_memory = log2_strict_usize(public_memory.len());
+    let log_memory = log2_ceil_usize(public_memory.len() + private_memory_len);
     let log_n_p16 = log2_ceil_usize(n_poseidons_16);
     let log_n_p24 = log2_ceil_usize(n_poseidons_24);
 

crates/lean_vm/src/memory.rs

@@ -5,7 +5,11 @@ use rayon::prelude::*;
 
 use crate::*;
 
-pub(crate) const MAX_MEMORY_SIZE: usize = 1 << 24;
+pub const MAX_MEMORY_SIZE: usize = 1 << 29;
+
+// For now, we restrict ourselves to executions where memory usage < 2^24 words.
+// But the VM supports theorically a memory of size MAX_MEMORY_SIZE = 2^29.
+pub(crate) const MAX_RUNNER_MEMORY_SIZE: usize = 1 << 24;
 
 #[derive(Debug, Clone, Default)]
 pub struct Memory(pub Vec<Option<F>>);
@@ -29,7 +33,7 @@ impl Memory {
 
     pub fn set(&mut self, index: usize, value: F) -> Result<(), RunnerError> {
         if index >= self.0.len() {
-            if index >= MAX_MEMORY_SIZE {
+            if index >= MAX_RUNNER_MEMORY_SIZE {
                 return Err(RunnerError::OutOfMemory);
             }
             self.0.resize(index + 1, None);

crates/lean_vm/src/runner.rs

@@ -101,7 +101,7 @@ pub fn execute_bytecode(
         bytecode,
         public_input,
         private_input,
-        MAX_MEMORY_SIZE / 2,
+        MAX_RUNNER_MEMORY_SIZE / 2,
         false,
         &mut std_out,
         &mut instruction_history,