merge

changelogs/unreleased/1041-schaeff

@@ -0,0 +1 @@
+Reduce compiler memory usage using iterators

zokrates_book/src/examples/rng_tutorial.md

@@ -31,7 +31,7 @@ Create this file under the name `get_hash.zok`:
 
 Compile the program to a form that is usable for zero knowledge proofs. This command writes 
 the binary to `get_hash`. You can see a textual representation, somewhat analogous to assembler 
-coming from a compiler, at `get_hash.ztf` enabled by the `--ztf` command line option.
+coming from a compiler, at `get_hash.ztf` created by the `inspect` command.
 ```
 {{#include ../../../zokrates_cli/examples/book/rng_tutorial/test.sh:10}}
 ```

zokrates_cli/examples/book/rng_tutorial/test.sh

@@ -7,7 +7,7 @@ function zokrates() {
   ZOKRATES_STDLIB=$stdlib $bin $*
 }
 
-zokrates compile -i get_hash.zok -o get_hash --ztf
+zokrates compile -i get_hash.zok -o get_hash && zokrates inspect -i get_hash
 zokrates compute-witness --verbose -i get_hash -a 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
 
 mkdir alice bob

zokrates_cli/src/ops/compute_witness.rs

@@ -83,12 +83,6 @@ fn cli_compute<T: Field, I: Iterator<Item = ir::Statement<T>>>(
     println!("Computing witness...");
 
     let verbose = sub_matches.is_present("verbose");
-
-    // print deserialized flattened program if in verbose mode
-    // if verbose {
-    //     println!("{}", ir_prog);
-    // }
-
     let is_stdin = sub_matches.is_present("stdin");
     let is_abi = sub_matches.is_present("abi");
 

zokrates_cli/src/ops/inspect.rs

@@ -9,7 +9,7 @@ use zokrates_field::Field;
 
 pub fn subcommand() -> App<'static, 'static> {
     SubCommand::with_name("inspect")
-        .about("Prints the compiled program in a human readable format")
+        .about("Outputs a compiled program to a file in a human readable format")
         .arg(
             Arg::with_name("input")
                 .short("i")

zokrates_core/src/compile.rs

@@ -198,10 +198,6 @@ pub fn compile<'ast, T: Field, E: Into<imports::Error>>(
     log::debug!("Flatten");
     let program_flattened = FlattenerIterator::from_function_and_config(typed_ast.main, config);
 
-    // // constant propagation after call resolution
-    // log::debug!("Propagate flat program");
-    // let program_flattened = program_flattened.propagate();
-
     // convert to ir
     log::debug!("Convert to IR");
     let ir_prog = ir::from_flat::from_flat(program_flattened);

zokrates_core/src/embed.rs

@@ -635,6 +635,7 @@ pub fn unpack_to_bitwidth<T: Field>(
 
     let solver = Solver::bits(bit_width);
 
+    #[allow(clippy::needless_collect)]
     let outputs: Vec<_> = directive_outputs
         .iter()
         .enumerate()

zokrates_core/src/flatten/mod.rs

@@ -1284,6 +1284,8 @@ impl<'ast, T: Field> Flattener<'ast, T> {
         // Rename Parameters, assign them to values in call. Resolve complex expressions with definitions
         let params_flattened = params.into_iter().map(|e| e.get_field_unchecked());
 
+        let return_values = (0..funct.return_count).map(FlatVariable::public);
+
         for (concrete_argument, formal_argument) in params_flattened.zip(funct.arguments) {
             let new_var = self.define(concrete_argument, statements_flattened);
             replacement_map.insert(formal_argument.id, new_var);
@@ -1329,17 +1331,10 @@ impl<'ast, T: Field> Flattener<'ast, T> {
 
         statements_flattened.extend(statements);
 
-        unimplemented!();
-
-        // match return_statements.pop().unwrap() {
-        //     FlatStatement::Return(list) => list
-        //         .expressions
-        //         .into_iter()
-        //         .map(|x| x.apply_substitution(&replacement_map))
-        //         .map(FlatUExpression::with_field)
-        //         .collect(),
-        //     _ => unreachable!(),
-        // }
+        return_values
+            .map(|x| FlatExpression::from(x).apply_substitution(&replacement_map))
+            .map(FlatUExpression::with_field)
+            .collect()
     }
 
     /// Flattens an expression
@@ -2368,6 +2363,9 @@ impl<'ast, T: Field> Flattener<'ast, T> {
     ) {
         match stat {
             ZirStatement::Return(exprs) => {
+                #[allow(clippy::needless_collect)]
+                // clippy suggests to not collect here, but `statements_flattened` is borrowed in the iterator,
+                // so we cannot borrow again when extending
                 let flat_expressions: Vec<_> = exprs
                     .into_iter()
                     .map(|expr| self.flatten_expression(statements_flattened, expr))

zokrates_core/src/ir/from_flat.rs

@@ -45,6 +45,10 @@ impl<T: Field> From<FlatExpression<T>> for LinComb<T> {
                 box FlatExpression::Identifier(v1),
                 box FlatExpression::Number(n1),
             ) => LinComb::summand(n1, v1),
+            FlatExpression::Mult(
+                box FlatExpression::Number(n1),
+                box FlatExpression::Number(n2),
+            ) => LinComb::summand(n1 * n2, FlatVariable::one()),
             e => unreachable!("{}", e),
         }
     }

zokrates_core/src/ir/serialize.rs

@@ -19,6 +19,13 @@ pub enum ProgEnum<
     Bw6_761Program(ProgIterator<Bw6_761Field, Bw6_761I>),
 }
 
+type MemoryProgEnum = ProgEnum<
+    Vec<Statement<Bls12_381Field>>,
+    Vec<Statement<Bn128Field>>,
+    Vec<Statement<Bls12_377Field>>,
+    Vec<Statement<Bw6_761Field>>,
+>;
+
 impl<
         Bls12_381I: IntoIterator<Item = Statement<Bls12_381Field>>,
         Bn128I: IntoIterator<Item = Statement<Bn128Field>>,
@@ -26,14 +33,7 @@ impl<
         Bw6_761I: IntoIterator<Item = Statement<Bw6_761Field>>,
     > ProgEnum<Bls12_381I, Bn128I, Bls12_377I, Bw6_761I>
 {
-    pub fn collect(
-        self,
-    ) -> ProgEnum<
-        Vec<Statement<Bls12_381Field>>,
-        Vec<Statement<Bn128Field>>,
-        Vec<Statement<Bls12_377Field>>,
-        Vec<Statement<Bw6_761Field>>,
-    > {
+    pub fn collect(self) -> MemoryProgEnum {
         match self {
             ProgEnum::Bls12_381Program(p) => ProgEnum::Bls12_381Program(p.collect()),
             ProgEnum::Bn128Program(p) => ProgEnum::Bn128Program(p.collect()),

zokrates_core/src/proof_system/libsnark/gm17.rs

@@ -204,7 +204,7 @@ mod tests {
     fn verify() {
         let program: Prog<Bn128Field> = Prog {
             arguments: vec![FlatParameter::private(FlatVariable::new(0))],
-            returns: vec![FlatVariable::public(0)],
+            return_count: 1,
             statements: vec![Statement::constraint(
                 FlatVariable::new(0),
                 FlatVariable::public(0),
@@ -215,7 +215,7 @@ mod tests {
         let interpreter = Interpreter::default();
 
         let witness = interpreter
-            .execute(&program, &vec![Bn128Field::from(42)])
+            .execute(program.clone(), &vec![Bn128Field::from(42)])
             .unwrap();
 
         let proof =

zokrates_core/src/proof_system/libsnark/pghr13.rs

@@ -234,7 +234,7 @@ mod tests {
     fn verify() {
         let program: Prog<Bn128Field> = Prog {
             arguments: vec![FlatParameter::private(FlatVariable::new(0))],
-            returns: vec![FlatVariable::public(0)],
+            return_count: 1,
             statements: vec![Statement::constraint(
                 FlatVariable::new(0),
                 FlatVariable::public(0),
@@ -245,7 +245,7 @@ mod tests {
         let interpreter = Interpreter::default();
 
         let witness = interpreter
-            .execute(&program, &vec![Bn128Field::from(42)])
+            .execute(program.clone(), &vec![Bn128Field::from(42)])
             .unwrap();
 
         let proof =