Introduce a simple test for global variables

cranelift/filetests/src/test_zkasm.rs

@@ -153,6 +153,11 @@ mod tests {
         // TODO: Preamble should be generated by a linker and/or clift itself.
         program.append(&mut generate_preamble(start_func.index()));
 
+        for (key, init) in &zkasm_environ.info.global_inits {
+            // program.push(format!("{}: MSTORE(MEM:E)", func_index));
+            dbg!(key, init);
+        }
+
         let num_func_imports = zkasm_environ.get_num_func_imports();
         let mut context = cranelift_codegen::Context::new();
         for (def_index, func) in zkasm_environ.info.function_bodies.iter() {
@@ -321,6 +326,7 @@ mod tests {
         add,
         locals,
         locals_simple,
+        global,
         memory,
         counter,
         add_func,

cranelift/wasm/src/environ/zkasm.rs

@@ -15,6 +15,7 @@ use crate::{
     WasmFuncType, WasmHeapType, WasmResult,
 };
 use core::convert::TryFrom;
+use std::collections::HashMap;
 use cranelift_codegen::cursor::FuncCursor;
 use cranelift_codegen::ir::immediates::{Imm64, Offset32, Uimm64};
 use cranelift_codegen::ir::{self, GlobalValue, InstBuilder};
@@ -82,6 +83,9 @@ pub struct ZkasmModuleInfo {
     /// Globals as provided by `declare_global`.
     pub globals: PrimaryMap<GlobalIndex, Exportable<Global>>,
 
+    /// Inits for globals when available.
+    pub global_inits: HashMap<GlobalIndex, GlobalInit>,
+
     /// The start function.
     pub start_func: Option<FuncIndex>,
 }
@@ -101,6 +105,7 @@ impl ZkasmModuleInfo {
             tables: PrimaryMap::new(),
             memories: PrimaryMap::new(),
             globals: PrimaryMap::new(),
+            global_inits: HashMap::new(),
             start_func: None,
         }
     }
@@ -770,8 +775,9 @@ impl<'data> ModuleEnvironment<'data> for ZkasmEnvironment {
         Ok(())
     }
 
-    fn declare_global(&mut self, global: Global, _init: GlobalInit) -> WasmResult<()> {
-        self.info.globals.push(Exportable::new(global));
+    fn declare_global(&mut self, global: Global, init: GlobalInit) -> WasmResult<()> {
+        let index = self.info.globals.push(Exportable::new(global));
+        self.info.global_inits.insert(index, init);
         Ok(())
     }
 

cranelift/zkasm_data/generated/global.zkasm

@@ -0,0 +1,33 @@
+start:
+  zkPC + 2 => RR
+  :JMP(function_1)
+  :JMP(finalizeExecution)
+function_1:
+  SP + 1 => SP
+  RR :MSTORE(SP - 1)
+  SP + 2 => SP
+  E :MSTORE(SP - 1)
+  B :MSTORE(SP - 2)
+  12884901888n => A  ;; LoadConst32(3)
+  65536 => E  ;; LoadExtName(User(userextname0))
+  ${ E >> 32 } => E
+  A :MSTORE(MEM:E + 16)
+  65536 => E  ;; LoadExtName(User(userextname0))
+  ${ E >> 32 } => E
+  $ => A :MLOAD(MEM:E + 8)
+  65536 => E  ;; LoadExtName(User(userextname0))
+  ${ E >> 32 } => E
+  $ => B :MLOAD(MEM:E + 16)
+  $ => A :ADD
+  4294967296n => B  ;; LoadConst32(1)
+  B :ASSERT
+  $ => E :MLOAD(SP - 1)
+  $ => B :MLOAD(SP - 2)
+  SP - 2 => SP
+  $ => RR :MLOAD(SP - 1)
+  SP - 1 => SP
+  :JMP(RR)
+finalizeExecution:
+  ${beforeLast()}  :JMPN(finalizeExecution)
+                   :JMP(start)
+INCLUDE "helpers/2-exp.zkasm"

cranelift/zkasm_data/global.wat

@@ -0,0 +1,12 @@
+(module
+ (import "env" "assert_eq" (func $assert_eq (param i32) (param i32)))
+ (global $a i32 (i32.const -2))
+ (global $b (mut i32) (i32.const 5))
+ (func $main
+	(global.set $b (i32.const 3))
+	(global.get $a)
+	(global.get $b)
+	i32.add
+	i32.const 1
+	call $assert_eq)
+ (start $main))