chore(ssa refactor): Implement ssa-gen for indexing, cast, constrain,…

… if, unary (#1225)

* Implement ssa-gen for if

* Satisfy the clippy gods

crates/noirc_evaluator/src/ssa_refactor/ir/cfg.rs

@@ -133,29 +133,27 @@ mod tests {
         // Build function of form
         // fn func {
         // block0(cond: u1):
-        //     jmpif cond(), then: block2, else: block1
+        //     jmpif cond, then: block2, else: block1
         // block1():
-        //     jmpif cond(), then: block1, else: block2
+        //     jmpif cond, then: block1, else: block2
         // block2():
-        //     return
+        //     return ()
         // }
         let mut func = Function::new("func".into());
         let block0_id = func.entry_block();
         let cond = func.dfg.add_block_parameter(block0_id, Type::unsigned(1));
-        let block1_id = func.dfg.new_block();
-        let block2_id = func.dfg.new_block();
+        let block1_id = func.dfg.make_block();
+        let block2_id = func.dfg.make_block();
 
         func.dfg[block0_id].set_terminator(TerminatorInstruction::JmpIf {
             condition: cond,
             then_destination: block2_id,
             else_destination: block1_id,
-            arguments: vec![],
         });
         func.dfg[block1_id].set_terminator(TerminatorInstruction::JmpIf {
             condition: cond,
             then_destination: block1_id,
             else_destination: block2_id,
-            arguments: vec![],
         });
         func.dfg[block2_id].set_terminator(TerminatorInstruction::Return { return_values: vec![] });
 
@@ -192,15 +190,15 @@ mod tests {
         // Modify function to form:
         // fn func {
         // block0(cond: u1):
-        //     jmpif cond(), then: block1, else: ret_block
+        //     jmpif cond, then: block1, else: ret_block
         // block1():
-        //     jmpif cond(), then: block1, else: block2
+        //     jmpif cond, then: block1, else: block2
         // block2():
-        //     jmp ret_block
+        //     jmp ret_block()
         // ret_block():
-        //     return
+        //     return ()
         // }
-        let ret_block_id = func.dfg.new_block();
+        let ret_block_id = func.dfg.make_block();
         func.dfg[ret_block_id]
             .set_terminator(TerminatorInstruction::Return { return_values: vec![] });
         func.dfg[block2_id].set_terminator(TerminatorInstruction::Jmp {
@@ -211,7 +209,6 @@ mod tests {
             condition: cond,
             then_destination: block1_id,
             else_destination: ret_block_id,
-            arguments: vec![],
         });
 
         // Recompute new and changed blocks

crates/noirc_evaluator/src/ssa_refactor/ir/constant.rs

@@ -16,8 +16,8 @@ impl NumericConstant {
         Self(value)
     }
 
-    pub(crate) fn value(&self) -> &FieldElement {
-        &self.0
+    pub(crate) fn value(&self) -> FieldElement {
+        self.0
     }
 }
 

crates/noirc_evaluator/src/ssa_refactor/ir/dfg.rs

@@ -2,7 +2,7 @@ use super::{
     basic_block::{BasicBlock, BasicBlockId},
     constant::{NumericConstant, NumericConstantId},
     function::Signature,
-    instruction::{Instruction, InstructionId, InstructionResultType},
+    instruction::{Instruction, InstructionId, InstructionResultType, TerminatorInstruction},
     map::{DenseMap, Id, SecondaryMap, TwoWayMap},
     types::Type,
     value::{Value, ValueId},
@@ -75,14 +75,14 @@ impl DataFlowGraph {
     /// Creates a new basic block with no parameters.
     /// After being created, the block is unreachable in the current function
     /// until another block is made to jump to it.
-    pub(crate) fn new_block(&mut self) -> BasicBlockId {
+    pub(crate) fn make_block(&mut self) -> BasicBlockId {
         self.blocks.insert(BasicBlock::new(Vec::new()))
     }
 
     /// Creates a new basic block with the given parameters.
     /// After being created, the block is unreachable in the current function
     /// until another block is made to jump to it.
-    pub(crate) fn new_block_with_parameters(
+    pub(crate) fn make_block_with_parameters(
         &mut self,
         parameter_types: impl Iterator<Item = Type>,
     ) -> BasicBlockId {
@@ -230,6 +230,24 @@ impl DataFlowGraph {
     ) {
         self.blocks[block].insert_instruction(instruction);
     }
+
+    /// Returns the field element represented by this value if it is a numeric constant.
+    /// Returns None if the given value is not a numeric constant.
+    pub(crate) fn get_numeric_constant(&self, value: Id<Value>) -> Option<FieldElement> {
+        match self.values[value] {
+            Value::NumericConstant { constant, .. } => Some(self[constant].value()),
+            _ => None,
+        }
+    }
+
+    /// Sets the terminator instruction for the given basic block
+    pub(crate) fn set_block_terminator(
+        &mut self,
+        block: BasicBlockId,
+        terminator: TerminatorInstruction,
+    ) {
+        self.blocks[block].set_terminator(terminator);
+    }
 }
 
 impl std::ops::Index<InstructionId> for DataFlowGraph {

crates/noirc_evaluator/src/ssa_refactor/ir/function.rs

@@ -32,7 +32,7 @@ impl Function {
     /// Note that any parameters to the function must be manually added later.
     pub(crate) fn new(name: String) -> Self {
         let mut dfg = DataFlowGraph::default();
-        let entry_block = dfg.new_block();
+        let entry_block = dfg.make_block();
         Self { name, source_locations: SecondaryMap::new(), entry_block, dfg }
     }
 

crates/noirc_evaluator/src/ssa_refactor/ir/instruction.rs

@@ -150,14 +150,9 @@ pub(crate) enum TerminatorInstruction {
     ///
     /// Jump If
     ///
-    /// If the condition is true: jump to the specified `then_destination` with `arguments`.
-    /// Otherwise, jump to the specified `else_destination` with `arguments`.
-    JmpIf {
-        condition: ValueId,
-        then_destination: BasicBlockId,
-        else_destination: BasicBlockId,
-        arguments: Vec<ValueId>,
-    },
+    /// If the condition is true: jump to the specified `then_destination`.
+    /// Otherwise, jump to the specified `else_destination`.
+    JmpIf { condition: ValueId, then_destination: BasicBlockId, else_destination: BasicBlockId },
 
     /// Unconditional Jump
     ///

crates/noirc_evaluator/src/ssa_refactor/ir/printer.rs

@@ -57,17 +57,11 @@ pub(crate) fn display_terminator(
         Some(TerminatorInstruction::Jmp { destination, arguments }) => {
             writeln!(f, "    jmp {}({})", destination, value_list(arguments))
         }
-        Some(TerminatorInstruction::JmpIf {
-            condition,
-            arguments,
-            then_destination,
-            else_destination,
-        }) => {
-            let args = value_list(arguments);
+        Some(TerminatorInstruction::JmpIf { condition, then_destination, else_destination }) => {
             writeln!(
                 f,
-                "    jmpif {}({}) then: {}, else: {}",
-                condition, args, then_destination, else_destination
+                "    jmpif {} then: {}, else: {}",
+                condition, then_destination, else_destination
             )
         }
         Some(TerminatorInstruction::Return { return_values }) => {

crates/noirc_evaluator/src/ssa_refactor/ssa_builder/function_builder.rs

@@ -3,7 +3,7 @@ use acvm::FieldElement;
 use crate::ssa_refactor::ir::{
     basic_block::BasicBlockId,
     function::{Function, FunctionId},
-    instruction::{Binary, BinaryOp, Instruction},
+    instruction::{Binary, BinaryOp, Instruction, TerminatorInstruction},
     types::Type,
     value::ValueId,
 };
@@ -62,15 +62,32 @@ impl<'ssa> FunctionBuilder<'ssa> {
     }
 
     /// Insert a numeric constant into the current function
-    pub(crate) fn numeric_constant(&mut self, value: FieldElement, typ: Type) -> ValueId {
-        self.current_function.dfg.make_constant(value, typ)
+    pub(crate) fn numeric_constant(
+        &mut self,
+        value: impl Into<FieldElement>,
+        typ: Type,
+    ) -> ValueId {
+        self.current_function.dfg.make_constant(value.into(), typ)
     }
 
     /// Insert a numeric constant into the current function of type Field
     pub(crate) fn field_constant(&mut self, value: impl Into<FieldElement>) -> ValueId {
         self.numeric_constant(value.into(), Type::field())
     }
 
+    pub(crate) fn type_of_value(&self, value: ValueId) -> Type {
+        self.current_function.dfg.type_of_value(value)
+    }
+
+    pub(crate) fn insert_block(&mut self) -> BasicBlockId {
+        self.current_function.dfg.make_block()
+    }
+
+    pub(crate) fn add_block_parameter(&mut self, block: BasicBlockId, typ: Type) -> ValueId {
+        self.current_function.dfg.add_block_parameter(block, typ)
+    }
+
+    /// Inserts a new instruction at the end of the current block and returns its results
     fn insert_instruction(
         &mut self,
         instruction: Instruction,
@@ -81,23 +98,45 @@ impl<'ssa> FunctionBuilder<'ssa> {
         self.current_function.dfg.instruction_results(id)
     }
 
+    /// Switch to inserting instructions in the given block.
+    /// Expects the given block to be within the same function. If you want to insert
+    /// instructions into a new function, call new_function instead.
+    pub(crate) fn switch_to_block(&mut self, block: BasicBlockId) {
+        self.current_block = block;
+    }
+
     /// Insert an allocate instruction at the end of the current block, allocating the
     /// given amount of field elements. Returns the result of the allocate instruction,
     /// which is always a Reference to the allocated data.
     pub(crate) fn insert_allocate(&mut self, size_to_allocate: u32) -> ValueId {
         self.insert_instruction(Instruction::Allocate { size: size_to_allocate }, None)[0]
     }
 
-    /// Insert a Load instruction at the end of the current block, loading from the given address
-    /// which should point to a previous Allocate instruction. Note that this is limited to loading
-    /// a single value. Loading multiple values (such as a tuple) will require multiple loads.
+    /// Insert a Load instruction at the end of the current block, loading from the given offset
+    /// of the given address which should point to a previous Allocate instruction. Note that
+    /// this is limited to loading a single value. Loading multiple values (such as a tuple)
+    /// will require multiple loads.
+    /// 'offset' is in units of FieldElements here. So loading the fourth FieldElement stored in
+    /// an array will have an offset of 3.
     /// Returns the element that was loaded.
-    pub(crate) fn insert_load(&mut self, address: ValueId, type_to_load: Type) -> ValueId {
+    pub(crate) fn insert_load(
+        &mut self,
+        mut address: ValueId,
+        offset: ValueId,
+        type_to_load: Type,
+    ) -> ValueId {
+        if let Some(offset) = self.current_function.dfg.get_numeric_constant(offset) {
+            if !offset.is_zero() {
+                let offset = self.field_constant(offset);
+                address = self.insert_binary(address, BinaryOp::Add, offset);
+            }
+        };
         self.insert_instruction(Instruction::Load { address }, Some(vec![type_to_load]))[0]
     }
 
     /// Insert a Store instruction at the end of the current block, storing the given element
-    /// at the given address. Expects that the address points to a previous Allocate instruction.
+    /// at the given address. Expects that the address points somewhere
+    /// within a previous Allocate instruction.
     pub(crate) fn insert_store(&mut self, address: ValueId, value: ValueId) {
         self.insert_instruction(Instruction::Store { address, value }, None);
     }
@@ -119,4 +158,50 @@ impl<'ssa> FunctionBuilder<'ssa> {
     pub(crate) fn insert_not(&mut self, rhs: ValueId) -> ValueId {
         self.insert_instruction(Instruction::Not(rhs), None)[0]
     }
+
+    /// Insert a cast instruction at the end of the current block.
+    /// Returns the result of the cast instruction.
+    pub(crate) fn insert_cast(&mut self, value: ValueId, typ: Type) -> ValueId {
+        self.insert_instruction(Instruction::Cast(value, typ), None)[0]
+    }
+
+    /// Insert a constrain instruction at the end of the current block.
+    pub(crate) fn insert_constrain(&mut self, boolean: ValueId) {
+        self.insert_instruction(Instruction::Constrain(boolean), None);
+    }
+
+    /// Terminates the current block with the given terminator instruction
+    fn terminate_block_with(&mut self, terminator: TerminatorInstruction) {
+        self.current_function.dfg.set_block_terminator(self.current_block, terminator);
+    }
+
+    /// Terminate the current block with a jmp instruction to jmp to the given
+    /// block with the given arguments.
+    pub(crate) fn terminate_with_jmp(
+        &mut self,
+        destination: BasicBlockId,
+        arguments: Vec<ValueId>,
+    ) {
+        self.terminate_block_with(TerminatorInstruction::Jmp { destination, arguments });
+    }
+
+    /// Terminate the current block with a jmpif instruction to jmp with the given arguments
+    /// block with the given arguments.
+    pub(crate) fn terminate_with_jmpif(
+        &mut self,
+        condition: ValueId,
+        then_destination: BasicBlockId,
+        else_destination: BasicBlockId,
+    ) {
+        self.terminate_block_with(TerminatorInstruction::JmpIf {
+            condition,
+            then_destination,
+            else_destination,
+        });
+    }
+
+    /// Terminate the current block with a return instruction
+    pub(crate) fn terminate_with_return(&mut self, return_values: Vec<ValueId>) {
+        self.terminate_block_with(TerminatorInstruction::Return { return_values });
+    }
 }

crates/noirc_evaluator/src/ssa_refactor/ssa_gen/context.rs

@@ -129,7 +129,7 @@ impl<'a> FunctionContext<'a> {
     /// Insert a unit constant into the current function if not already
     /// present, and return its value
     pub(super) fn unit_value(&mut self) -> Values {
-        self.builder.numeric_constant(0u128.into(), Type::Unit).into()
+        self.builder.numeric_constant(0u128, Type::Unit).into()
     }
 
     /// Insert a binary instruction at the end of the current block.
@@ -155,6 +155,15 @@ impl<'a> FunctionContext<'a> {
         }
         result.into()
     }
+
+    /// Create a const offset of an address for an array load or store
+    pub(super) fn make_offset(&mut self, mut address: ValueId, offset: u128) -> ValueId {
+        if offset != 0 {
+            let offset = self.builder.field_constant(offset);
+            address = self.builder.insert_binary(address, BinaryOp::Add, offset);
+        }
+        address
+    }
 }
 
 /// True if the given operator cannot be encoded directly and needs