Merge pull request #246 from maticnetwork/decoder-trace2

Add op batch flags to decoder trace

core/src/decoder/mod.rs

@@ -1,4 +1,4 @@
-use super::{range, Operation};
+use super::{range, Felt, Operation, ONE, ZERO};
 use core::ops::Range;
 
 // CONSTANTS
@@ -8,27 +8,51 @@ use core::ops::Range;
 pub const ADDR_COL_IDX: usize = 0;
 
 /// Index at which operation bit columns start in the decoder trace.
-pub const OP_BITS_OFFSET: usize = 1;
+pub const OP_BITS_OFFSET: usize = ADDR_COL_IDX + 1;
 
-/// Location of operation bits columns in the decoder trace.
-pub const OP_BITS_RANGE: Range<usize> = range(OP_BITS_OFFSET, Operation::OP_BITS);
-
-/// Index of the in_span column in the decoder trace.
-pub const IN_SPAN_COL_IDX: usize = 8;
-
-/// Index of the operation group count column in the decoder trace.
-pub const GROUP_COUNT_COL_IDX: usize = 17;
+/// Number of columns needed to hold a binary representation of opcodes.
+pub const NUM_OP_BITS: usize = Operation::OP_BITS;
 
-/// Index of the operation index column in the decoder trace.
-pub const OP_INDEX_COL_IDX: usize = 18;
+/// Location of operation bits columns in the decoder trace.
+pub const OP_BITS_RANGE: Range<usize> = range(OP_BITS_OFFSET, NUM_OP_BITS);
 
 // TODO: probably rename "hasher state" to something like "shared columns".
 
 /// Index at which hasher state columns start in the decoder trace.
-pub const HASHER_STATE_OFFSET: usize = 9;
+pub const HASHER_STATE_OFFSET: usize = OP_BITS_OFFSET + NUM_OP_BITS;
 
 /// Number of hasher columns in the decoder trace.
 pub const NUM_HASHER_COLUMNS: usize = 8;
 
 /// Location of hasher columns in the decoder trace.
 pub const HASHER_STATE_RANGE: Range<usize> = range(HASHER_STATE_OFFSET, NUM_HASHER_COLUMNS);
+
+/// Index of the in_span column in the decoder trace.
+pub const IN_SPAN_COL_IDX: usize = HASHER_STATE_OFFSET + NUM_HASHER_COLUMNS;
+
+/// Index of the operation group count column in the decoder trace.
+pub const GROUP_COUNT_COL_IDX: usize = IN_SPAN_COL_IDX + 1;
+
+/// Index of the operation index column in the decoder trace.
+pub const OP_INDEX_COL_IDX: usize = GROUP_COUNT_COL_IDX + 1;
+
+/// Index at which operation batch flag columns start in the decoder trace.
+pub const OP_BATCH_FLAGS_OFFSET: usize = OP_INDEX_COL_IDX + 1;
+
+/// Number of operation batch flag columns.
+pub const NUM_OP_BATCH_FLAGS: usize = 3;
+
+/// Location of operation batch flag columns in the decoder trace.
+pub const OP_BATCH_FLAGS_RANGE: Range<usize> = range(OP_BATCH_FLAGS_OFFSET, NUM_OP_BATCH_FLAGS);
+
+/// Operation batch consists of 8 operation groups.
+pub const OP_BATCH_8_GROUPS: [Felt; NUM_OP_BATCH_FLAGS] = [ONE, ZERO, ZERO];
+
+/// Operation batch consists of 4 operation groups.
+pub const OP_BATCH_4_GROUPS: [Felt; NUM_OP_BATCH_FLAGS] = [ZERO, ONE, ZERO];
+
+/// Operation batch consists of 2 operation groups.
+pub const OP_BATCH_2_GROUPS: [Felt; NUM_OP_BATCH_FLAGS] = [ZERO, ZERO, ONE];
+
+/// Operation batch consists of 1 operation group.
+pub const OP_BATCH_1_GROUPS: [Felt; NUM_OP_BATCH_FLAGS] = [ZERO, ONE, ONE];

core/src/lib.rs

@@ -34,6 +34,12 @@ pub type StackTopState = [Felt; MIN_STACK_DEPTH];
 // CONSTANTS
 // ================================================================================================
 
+/// Field element representing ZERO in the base field of the VM.
+pub const ZERO: Felt = Felt::ZERO;
+
+/// Field element representing ONE in the base field of the VM.
+pub const ONE: Felt = Felt::ONE;
+
 /// The minimum length of the execution trace. This is the minimum required to support range checks.
 pub const MIN_TRACE_LEN: usize = 1024;
 
@@ -48,7 +54,7 @@ pub const NUM_STACK_HELPER_COLS: usize = 3;
 // ------------------------------------------------------------------------------------------------
 
 //      system          decoder           stack      range checks    auxiliary table
-//    (2 columns)     (19 columns)    (19 columns)    (4 columns)     (18 columns)
+//    (2 columns)     (22 columns)    (19 columns)    (4 columns)     (18 columns)
 // ├───────────────┴───────────────┴───────────────┴───────────────┴─────────────────┤
 
 pub const SYS_TRACE_OFFSET: usize = 0;
@@ -60,7 +66,7 @@ pub const FMP_COL_IDX: usize = SYS_TRACE_OFFSET + 1;
 
 // decoder trace
 pub const DECODER_TRACE_OFFSET: usize = SYS_TRACE_OFFSET + SYS_TRACE_WIDTH;
-pub const DECODER_TRACE_WIDTH: usize = 19;
+pub const DECODER_TRACE_WIDTH: usize = 22;
 pub const DECODER_TRACE_RANGE: Range<usize> = range(DECODER_TRACE_OFFSET, DECODER_TRACE_WIDTH);
 
 // Stack trace

core/src/program/blocks/mod.rs

@@ -12,7 +12,10 @@ pub use call_block::Call;
 pub use join_block::Join;
 pub use loop_block::Loop;
 pub use proxy_block::Proxy;
-pub use span_block::{OpBatch, Span, BATCH_SIZE as OP_BATCH_SIZE, GROUP_SIZE as OP_GROUP_SIZE};
+pub use span_block::{
+    get_span_op_group_count, OpBatch, Span, BATCH_SIZE as OP_BATCH_SIZE,
+    GROUP_SIZE as OP_GROUP_SIZE,
+};
 pub use split_block::Split;
 
 // PROGRAM BLOCK

core/src/program/blocks/span_block.rs

@@ -68,15 +68,6 @@ impl Span {
         &self.op_batches
     }
 
-    /// Returns a list of operations contained in this span block.
-    pub fn get_ops(&self) -> Vec<Operation> {
-        let mut ops = Vec::with_capacity(self.op_batches.len() * MAX_OPS_PER_BATCH);
-        for batch in self.op_batches.iter() {
-            ops.extend_from_slice(&batch.ops);
-        }
-        ops
-    }
-
     // SPAN MUTATORS
     // --------------------------------------------------------------------------------------------
 
@@ -91,6 +82,18 @@ impl Span {
         }
         Self::new(ops)
     }
+
+    // HELPER METHODS
+    // --------------------------------------------------------------------------------------------
+
+    /// Returns a list of operations contained in this span block.
+    fn get_ops(&self) -> Vec<Operation> {
+        let mut ops = Vec::with_capacity(self.op_batches.len() * MAX_OPS_PER_BATCH);
+        for batch in self.op_batches.iter() {
+            ops.extend_from_slice(&batch.ops);
+        }
+        ops
+    }
 }
 
 impl fmt::Display for Span {
@@ -324,11 +327,29 @@ fn batch_ops(ops: Vec<Operation>) -> (Vec<OpBatch>, Digest) {
         batches.push(batch);
     }
 
-    let hash = hasher::hash_elements(flatten_slice_elements(&batch_groups));
+    // compute the hash of all operation groups
+    let num_op_groups = get_span_op_group_count(&batches);
+    let op_groups = &flatten_slice_elements(&batch_groups)[..num_op_groups];
+    let hash = hasher::hash_elements(op_groups);
 
     (batches, hash)
 }
 
+/// Returns the total number of operation groups in a span defined by the provides list of
+/// operation batches.
+///
+/// Then number of operation groups is computed as follows:
+/// - For all batches but the last one we set the number of groups to 8, regardless of the
+///   actual number of groups in the batch. The reason for this is that when operation
+///   batches are concatenated together each batch contributes 8 elements to the hash.
+/// - For the last batch, we take the number of actual batches and round it up to the next
+///   power of two. The reason for rounding is that the VM always executes a number of
+///   operation groups which is a power of two.
+pub fn get_span_op_group_count(op_batches: &[OpBatch]) -> usize {
+    let last_batch_num_groups = op_batches.last().expect("no last group").num_groups();
+    (op_batches.len() - 1) * BATCH_SIZE + last_batch_num_groups.next_power_of_two()
+}
+
 // TESTS
 // ================================================================================================
 
@@ -353,7 +374,7 @@ mod tests {
 
         assert_eq!(batch_groups, batch.groups);
         assert_eq!([1_usize, 0, 0, 0, 0, 0, 0, 0], batch.op_counts);
-        assert_eq!(hasher::hash_elements(&batch_groups), hash);
+        assert_eq!(hasher::hash_elements(&batch_groups[..1]), hash);
 
         // --- two operations ---------------------------------------------------------------------
         let ops = vec![Operation::Add, Operation::Mul];
@@ -369,7 +390,7 @@ mod tests {
 
         assert_eq!(batch_groups, batch.groups);
         assert_eq!([2_usize, 0, 0, 0, 0, 0, 0, 0], batch.op_counts);
-        assert_eq!(hasher::hash_elements(&batch_groups), hash);
+        assert_eq!(hasher::hash_elements(&batch_groups[..1]), hash);
 
         // --- one group with one immediate value -------------------------------------------------
         let ops = vec![Operation::Add, Operation::Push(Felt::new(12345678))];
@@ -386,7 +407,7 @@ mod tests {
 
         assert_eq!(batch_groups, batch.groups);
         assert_eq!([2_usize, 0, 0, 0, 0, 0, 0, 0], batch.op_counts);
-        assert_eq!(hasher::hash_elements(&batch_groups), hash);
+        assert_eq!(hasher::hash_elements(&batch_groups[..2]), hash);
 
         // --- one group with 7 immediate values --------------------------------------------------
         let ops = vec![
@@ -467,7 +488,7 @@ mod tests {
         assert_eq!(batch1_groups, batch1.groups);
 
         let all_groups = [batch0_groups, batch1_groups].concat();
-        assert_eq!(hasher::hash_elements(&all_groups), hash);
+        assert_eq!(hasher::hash_elements(&all_groups[..10]), hash);
 
         // --- immediate values in-between groups -------------------------------------------------
         let ops = vec![
@@ -503,7 +524,7 @@ mod tests {
 
         assert_eq!([9_usize, 0, 0, 1, 0, 0, 0, 0], batch.op_counts);
         assert_eq!(batch_groups, batch.groups);
-        assert_eq!(hasher::hash_elements(&batch_groups), hash);
+        assert_eq!(hasher::hash_elements(&batch_groups[..4]), hash);
 
         // --- push at the end of a group is moved into the next group ----------------------------
         let ops = vec![
@@ -537,7 +558,7 @@ mod tests {
 
         assert_eq!(batch_groups, batch.groups);
         assert_eq!([8_usize, 1, 0, 0, 0, 0, 0, 0], batch.op_counts);
-        assert_eq!(hasher::hash_elements(&batch_groups), hash);
+        assert_eq!(hasher::hash_elements(&batch_groups[..4]), hash);
 
         // --- push at the end of a group is moved into the next group ----------------------------
         let ops = vec![
@@ -571,7 +592,7 @@ mod tests {
 
         assert_eq!(batch_groups, batch.groups);
         assert_eq!([8_usize, 0, 1, 0, 0, 0, 0, 0], batch.op_counts);
-        assert_eq!(hasher::hash_elements(&batch_groups), hash);
+        assert_eq!(hasher::hash_elements(&batch_groups[..4]), hash);
 
         // --- push at the end of the 7th group overflows to the next batch -----------------------
         let ops = vec![
@@ -635,7 +656,7 @@ mod tests {
         assert_eq!([2_usize, 0, 0, 0, 0, 0, 0, 0], batch1.op_counts);
 
         let all_groups = [batch0_groups, batch1_groups].concat();
-        assert_eq!(hasher::hash_elements(&all_groups), hash);
+        assert_eq!(hasher::hash_elements(&all_groups[..10]), hash);
     }
 
     #[test]
@@ -654,7 +675,7 @@ mod tests {
         batch_groups[0] = build_group(&ops);
         batch_groups[1] = Felt::ONE;
         assert_eq!(batch_groups, batch.groups);
-        assert_eq!(hasher::hash_elements(&batch_groups), hash);
+        assert_eq!(hasher::hash_elements(&batch_groups[..2]), hash);
     }
 
     // TEST HELPERS

core/src/program/mod.rs

@@ -25,16 +25,14 @@ pub use library::Library;
 #[derive(Clone, Debug)]
 pub struct Script {
     root: CodeBlock,
-    hash: Digest,
 }
 
 impl Script {
     // CONSTRUCTOR
     // --------------------------------------------------------------------------------------------
     /// Constructs a new program from the specified code block.
     pub fn new(root: CodeBlock) -> Self {
-        let hash = hasher::merge(&[root.hash(), Digest::default()]);
-        Self { root, hash }
+        Self { root }
     }
 
     // PUBLIC ACCESSORS
@@ -46,8 +44,8 @@ impl Script {
     }
 
     /// Returns a hash of this script.
-    pub fn hash(&self) -> &Digest {
-        &self.hash
+    pub fn hash(&self) -> Digest {
+        self.root.hash()
     }
 }
 

examples/src/lib.rs

@@ -72,8 +72,8 @@ pub fn test_example(example: Example, fail: bool) {
 
     if fail {
         outputs[0] += 1;
-        assert!(miden::verify(*program.hash(), &pub_inputs, &outputs, proof).is_err())
+        assert!(miden::verify(program.hash(), &pub_inputs, &outputs, proof).is_err())
     } else {
-        assert!(miden::verify(*program.hash(), &pub_inputs, &outputs, proof).is_ok());
+        assert!(miden::verify(program.hash(), &pub_inputs, &outputs, proof).is_ok());
     }
 }

examples/src/main.rs

@@ -64,7 +64,7 @@ fn main() {
     // results in the expected output
     let proof = StarkProof::from_bytes(&proof_bytes).unwrap();
     let now = Instant::now();
-    match miden::verify(*program.hash(), &pub_inputs, &outputs, proof) {
+    match miden::verify(program.hash(), &pub_inputs, &outputs, proof) {
         Ok(_) => debug!("Execution verified in {} ms", now.elapsed().as_millis()),
         Err(err) => debug!("Failed to verify execution: {}", err),
     }

miden/tests/integration/helpers/mod.rs

@@ -163,9 +163,9 @@ impl Test {
 
         if test_fail {
             outputs[0] += 1;
-            assert!(miden::verify(*script.hash(), &pub_inputs, &outputs, proof).is_err());
+            assert!(miden::verify(script.hash(), &pub_inputs, &outputs, proof).is_err());
         } else {
-            assert!(miden::verify(*script.hash(), &pub_inputs, &outputs, proof).is_ok());
+            assert!(miden::verify(script.hash(), &pub_inputs, &outputs, proof).is_ok());
         }
     }