IR: ssa-foundation: ensure strict SSA

crates/herkos/src/codegen/instruction.rs

@@ -103,6 +103,14 @@ pub fn generate_instruction_with_info<B: Backend>(
             val2,
             condition,
         } => backend.emit_select(*dest, *val1, *val2, *condition),
+
+        // Phi nodes must be lowered to Assign instructions by the lower_phis pass
+        // before codegen runs. Reaching this arm is a compiler bug.
+        IrInstr::Phi { .. } => {
+            unreachable!(
+                "IrInstr::Phi must be lowered before codegen (lower_phis pass missed this block)"
+            )
+        }
     };
     Ok(code)
 }

crates/herkos/src/codegen/mod.rs

@@ -165,7 +165,7 @@ impl<'a, B: Backend> CodeGenerator<'a, B> {
     /// Generate a complete Rust module from IR with full module info.
     ///
     /// This is the main entry point. It generates a module wrapper structure.
-    pub fn generate_module_with_info(&self, info: &ModuleInfo) -> Result<String> {
+    pub fn generate_module_with_info(&self, info: &LoweredModuleInfo) -> Result<String> {
         module::generate_module_with_info(self.backend, info)
     }
 }
@@ -500,7 +500,8 @@ mod tests {
 
         let backend = SafeBackend::new();
         let codegen = CodeGenerator::new(&backend);
-        let code = codegen.generate_module_with_info(&info).unwrap();
+        let lowered = crate::ir::lower_phis::lower(info);
+        let code = codegen.generate_module_with_info(&lowered).unwrap();
 
         println!("Generated wrapper code:\n{}", code);
 
@@ -566,7 +567,8 @@ mod tests {
 
         let backend = SafeBackend::new();
         let codegen = CodeGenerator::new(&backend);
-        let code = codegen.generate_module_with_info(&info).unwrap();
+        let lowered = crate::ir::lower_phis::lower(info);
+        let code = codegen.generate_module_with_info(&lowered).unwrap();
 
         println!("Generated wrapper code:\n{}", code);
 
@@ -633,7 +635,8 @@ mod tests {
 
         let backend = SafeBackend::new();
         let codegen = CodeGenerator::new(&backend);
-        let code = codegen.generate_module_with_info(&info).unwrap();
+        let lowered = crate::ir::lower_phis::lower(info);
+        let code = codegen.generate_module_with_info(&lowered).unwrap();
 
         println!("Generated code with immutable global:\n{}", code);
 

crates/herkos/src/codegen/module.rs

@@ -15,7 +15,10 @@ use anyhow::{Context, Result};
 /// Generate a complete Rust module from IR functions with full module info.
 ///
 /// This is the main entry point. It generates a module wrapper structure.
-pub fn generate_module_with_info<B: Backend>(backend: &B, info: &ModuleInfo) -> Result<String> {
+pub fn generate_module_with_info<B: Backend>(
+    backend: &B,
+    info: &LoweredModuleInfo,
+) -> Result<String> {
     generate_wrapper_module(backend, info)
 }