feat: SSA globals in monomorphization and SSA gen

compiler/noirc_evaluator/src/acir/mod.rs

@@ -1892,6 +1892,9 @@ impl<'a> Context<'a> {
             Value::Instruction { .. } | Value::Param { .. } => {
                 unreachable!("ICE: Should have been in cache {value_id} {value:?}")
             }
+            Value::Global(_) => {
+                unreachable!("ICE: All globals should have been inlined");
+            }
         };
         self.ssa_values.insert(value_id, acir_value.clone());
         acir_value

compiler/noirc_evaluator/src/brillig/brillig_gen/brillig_block.rs

@@ -646,7 +646,10 @@ impl<'block> BrilligBlock<'block> {
                         }
                     }
                 }
-                Value::Instruction { .. } | Value::Param { .. } | Value::NumericConstant { .. } => {
+                Value::Instruction { .. }
+                | Value::Param { .. }
+                | Value::NumericConstant { .. }
+                | Value::Global(_) => {
                     unreachable!("unsupported function call type {:?}", dfg[*func])
                 }
             },
@@ -1557,6 +1560,9 @@ impl<'block> BrilligBlock<'block> {
         let value = &dfg[value_id];
 
         match value {
+            Value::Global(_) => {
+                unreachable!("ICE: All globals should have been inlined");
+            }
             Value::Param { .. } | Value::Instruction { .. } => {
                 // All block parameters and instruction results should have already been
                 // converted to registers so we fetch from the cache.

compiler/noirc_evaluator/src/brillig/brillig_gen/variable_liveness.rs

@@ -53,9 +53,10 @@ pub(crate) fn collect_variables_of_value(
     let value = &dfg[value_id];
 
     match value {
-        Value::Instruction { .. } | Value::Param { .. } | Value::NumericConstant { .. } => {
-            Some(value_id)
-        }
+        Value::Instruction { .. }
+        | Value::Param { .. }
+        | Value::NumericConstant { .. }
+        | Value::Global(_) => Some(value_id),
         // Functions are not variables in a defunctionalized SSA. Only constant function values should appear.
         Value::ForeignFunction(_) | Value::Function(_) | Value::Intrinsic(..) => None,
     }

compiler/noirc_evaluator/src/ssa.rs

@@ -453,7 +453,7 @@ impl SsaBuilder {
             let ssa_path = emit_ssa.with_extension("ssa.json");
             write_to_file(&serde_json::to_vec(&ssa).unwrap(), &ssa_path);
         }
-        Ok(SsaBuilder { ssa_logging, print_codegen_timings, ssa }.print("Initial SSA:"))
+        Ok(SsaBuilder { ssa_logging, print_codegen_timings, ssa }.print("Initial SSA"))
     }
 
     fn finish(self) -> Ssa {

compiler/noirc_evaluator/src/ssa/checks/check_for_underconstrained_values.rs

@@ -332,7 +332,8 @@ impl DependencyContext {
                         }
                         Value::Instruction { .. }
                         | Value::NumericConstant { .. }
-                        | Value::Param { .. } => {
+                        | Value::Param { .. }
+                        | Value::Global(_) => {
                             panic!(
                                 "calling non-function value with ID {func_id} in function {}",
                                 function.name()
@@ -618,7 +619,8 @@ impl Context {
                         }
                         Value::Instruction { .. }
                         | Value::NumericConstant { .. }
-                        | Value::Param { .. } => {
+                        | Value::Param { .. }
+                        | Value::Global(_) => {
                             panic!("At the point we are running disconnect there shouldn't be any other values as arguments")
                         }
                     }

compiler/noirc_evaluator/src/ssa/ir/dfg.rs

@@ -325,6 +325,10 @@ impl DataFlowGraph {
         id
     }
 
+    pub(crate) fn make_global(&mut self, typ: Type) -> ValueId {
+        self.values.insert(Value::Global(typ))
+    }
+
     /// Gets or creates a ValueId for the given FunctionId.
     pub(crate) fn import_function(&mut self, function: FunctionId) -> ValueId {
         if let Some(existing) = self.functions.get(&function) {
@@ -613,6 +617,9 @@ impl DataFlowGraph {
                 }
                 _ => false,
             },
+            // TODO: Make this true and handle instruction simplifications with globals.
+            // Currently all globals are inlined as a temporary measure so this is fine to have as false.
+            Value::Global(_) => false,
             _ => true,
         }
     }

compiler/noirc_evaluator/src/ssa/ir/function.rs

@@ -76,7 +76,7 @@ pub(crate) struct Function {
     /// Name of the function for debugging only
     name: String,
 
-    id: FunctionId,
+    id: Option<FunctionId>,
 
     /// The DataFlowGraph holds the majority of data pertaining to the function
     /// including its blocks, instructions, and values.
@@ -90,14 +90,22 @@ impl Function {
     pub(crate) fn new(name: String, id: FunctionId) -> Self {
         let mut dfg = DataFlowGraph::default();
         let entry_block = dfg.make_block();
-        Self { name, id, entry_block, dfg }
+        Self { name, id: Some(id), entry_block, dfg }
+    }
+
+    /// Globals are generated using the same codegen process as functions.
+    /// To avoid a recursive global context we should create a pseudo function to mock a globals context.
+    pub(crate) fn new_for_globals() -> Self {
+        let mut dfg = DataFlowGraph::default();
+        let entry_block = dfg.make_block();
+        Self { name: "globals".to_owned(), id: None, entry_block, dfg }
     }
 
     /// Creates a new function as a clone of the one passed in with the passed in id.
     pub(crate) fn clone_with_id(id: FunctionId, another: &Function) -> Self {
         let dfg = another.dfg.clone();
         let entry_block = another.entry_block;
-        Self { name: another.name.clone(), id, entry_block, dfg }
+        Self { name: another.name.clone(), id: Some(id), entry_block, dfg }
     }
 
     /// Takes the signature (function name & runtime) from a function but does not copy the body.
@@ -115,7 +123,7 @@ impl Function {
 
     /// The id of the function.
     pub(crate) fn id(&self) -> FunctionId {
-        self.id
+        self.id.expect("FunctionId should be initialized")
     }
 
     /// Runtime type of the function.
@@ -228,12 +236,6 @@ pub(crate) struct Signature {
     pub(crate) returns: Vec<Type>,
 }
 
-impl std::fmt::Display for Function {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        super::printer::display_function(self, f)
-    }
-}
-
 #[test]
 fn sign_smoke() {
     let mut signature = Signature::default();

compiler/noirc_evaluator/src/ssa/ir/printer.rs

@@ -1,11 +1,14 @@
 //! This file is for pretty-printing the SSA IR in a human-readable form for debugging.
-use std::fmt::{Formatter, Result};
+use std::fmt::{Display, Formatter, Result};
 
 use acvm::acir::AcirField;
 use im::Vector;
 use iter_extended::vecmap;
 
-use crate::ssa::ir::types::{NumericType, Type};
+use crate::ssa::{
+    ir::types::{NumericType, Type},
+    Ssa,
+};
 
 use super::{
     basic_block::BasicBlockId,
@@ -15,8 +18,42 @@ use super::{
     value::{Value, ValueId},
 };
 
+impl Display for Ssa {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+        for (id, global_value) in self.globals.dfg.values_iter() {
+            match global_value {
+                Value::NumericConstant { constant, typ } => {
+                    writeln!(f, "g{} = {typ} {constant}", id.to_u32())?;
+                }
+                Value::Instruction { instruction, .. } => {
+                    display_instruction(&self.globals.dfg, *instruction, true, f)?;
+                }
+                Value::Global(_) => {
+                    panic!("Value::Global should only be in the function dfg");
+                }
+                _ => panic!("Expected only numeric constant or instruction"),
+            };
+        }
+
+        if self.globals.dfg.values_iter().len() > 0 {
+            writeln!(f)?;
+        }
+
+        for function in self.functions.values() {
+            writeln!(f, "{function}")?;
+        }
+        Ok(())
+    }
+}
+
+impl Display for Function {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+        display_function(self, f)
+    }
+}
+
 /// Helper function for Function's Display impl to pretty-print the function with the given formatter.
-pub(crate) fn display_function(function: &Function, f: &mut Formatter) -> Result {
+fn display_function(function: &Function, f: &mut Formatter) -> Result {
     writeln!(f, "{} fn {} {} {{", function.runtime(), function.name(), function.id())?;
     for block_id in function.reachable_blocks() {
         display_block(&function.dfg, block_id, f)?;
@@ -25,17 +62,13 @@ pub(crate) fn display_function(function: &Function, f: &mut Formatter) -> Result
 }
 
 /// Display a single block. This will not display the block's successors.
-pub(crate) fn display_block(
-    dfg: &DataFlowGraph,
-    block_id: BasicBlockId,
-    f: &mut Formatter,
-) -> Result {
+fn display_block(dfg: &DataFlowGraph, block_id: BasicBlockId, f: &mut Formatter) -> Result {
     let block = &dfg[block_id];
 
     writeln!(f, "  {}({}):", block_id, value_list_with_types(dfg, block.parameters()))?;
 
     for instruction in block.instructions() {
-        display_instruction(dfg, *instruction, f)?;
+        display_instruction(dfg, *instruction, false, f)?;
     }
 
     display_terminator(dfg, block.terminator(), f)
@@ -53,6 +86,9 @@ fn value(dfg: &DataFlowGraph, id: ValueId) -> String {
         Value::Intrinsic(intrinsic) => intrinsic.to_string(),
         Value::ForeignFunction(function) => function.clone(),
         Value::Param { .. } | Value::Instruction { .. } => id.to_string(),
+        Value::Global(_) => {
+            format!("g{}", id.to_u32())
+        }
     }
 }
 
@@ -72,7 +108,7 @@ fn value_list(dfg: &DataFlowGraph, values: &[ValueId]) -> String {
 }
 
 /// Display a terminator instruction
-pub(crate) fn display_terminator(
+fn display_terminator(
     dfg: &DataFlowGraph,
     terminator: Option<&TerminatorInstruction>,
     f: &mut Formatter,
@@ -107,17 +143,24 @@ pub(crate) fn display_terminator(
 }
 
 /// Display an arbitrary instruction
-pub(crate) fn display_instruction(
+fn display_instruction(
     dfg: &DataFlowGraph,
     instruction: InstructionId,
+    in_global_space: bool,
     f: &mut Formatter,
 ) -> Result {
-    // instructions are always indented within a function
-    write!(f, "    ")?;
+    if !in_global_space {
+        // instructions are always indented within a function
+        write!(f, "    ")?;
+    }
 
     let results = dfg.instruction_results(instruction);
     if !results.is_empty() {
-        write!(f, "{} = ", value_list(dfg, results))?;
+        let mut value_list = value_list(dfg, results);
+        if in_global_space {
+            value_list = value_list.replace('v', "g");
+        }
+        write!(f, "{} = ", value_list)?;
     }
 
     display_instruction_inner(dfg, &dfg[instruction], results, f)

compiler/noirc_evaluator/src/ssa/ir/value.rs

@@ -53,6 +53,9 @@ pub(crate) enum Value {
     /// ForeignFunction's always have the type Type::Function and have similar semantics to Function,
     /// other than generating different backend operations and being only accessible through Brillig.
     ForeignFunction(String),
+
+    /// This Value indicates we have a reserved slot that needs to be accessed in a separate global context
+    Global(Type),
 }
 
 impl Value {
@@ -64,6 +67,7 @@ impl Value {
             Value::Function { .. } | Value::Intrinsic { .. } | Value::ForeignFunction { .. } => {
                 Cow::Owned(Type::Function)
             }
+            Value::Global(typ) => Cow::Borrowed(typ),
         }
     }
 }