From fb29955f7d2a63fe5d832fa63483970e68472e2d Mon Sep 17 00:00:00 2001
From: VegOwOtenks <vego@owora.fritz.box>
Date: Mon, 2 Sep 2024 12:02:19 +0200
Subject: [PATCH] More error checking in invokestatic

---
 src/accessmasks.rs |  9 +++++++++
 src/classstore.rs  |  5 +++++
 src/jvm.rs         | 29 +++++++++++++++++++++++++++--
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/src/accessmasks.rs b/src/accessmasks.rs
index 33b7dbf..398fbdc 100644
--- a/src/accessmasks.rs
+++ b/src/accessmasks.rs
@@ -1,4 +1,5 @@
 use core::fmt::{Formatter, Debug};
+use core::ops::BitAnd;
 
 #[derive(Debug, Copy, Clone)] 
 #[repr(u16)]
@@ -36,10 +37,18 @@ impl MethodAccessFlag {
     }
 }
 
+#[derive(Copy, Clone)]
 pub struct MethodAccessFlagMask {
     pub mask: u16,
 }
 
+impl BitAnd<MethodAccessFlag> for MethodAccessFlagMask {
+    type Output=bool;
+    fn bitand(self, f: MethodAccessFlag) -> bool {
+        return (self.mask & f.discriminant()) != 0;
+    }
+}
+
 impl Debug for MethodAccessFlagMask {
     fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), std::fmt::Error> {
         let mut flag_vec = Vec::new();
diff --git a/src/classstore.rs b/src/classstore.rs
index 715302b..93df77f 100644
--- a/src/classstore.rs
+++ b/src/classstore.rs
@@ -130,6 +130,11 @@ impl ClassStore {
 
         return Some(was_init);
     }
+
+    pub fn set_init(&mut self, class_idx: usize, was_init: bool) {
+        let pair = self.classes.get_mut(class_idx).unwrap();
+        pair.0 = was_init;
+    }
 }
 
 
diff --git a/src/jvm.rs b/src/jvm.rs
index 385bb26..0b46519 100644
--- a/src/jvm.rs
+++ b/src/jvm.rs
@@ -17,6 +17,7 @@ pub enum Error {
     ClassFileError(classfile::Error),
     BadNameError(String),
     RunTimeError(String),
+    OpcodeError(String),
 }
 
 impl From<classfile::Error> for Error {
@@ -151,6 +152,7 @@ impl JVM {
         // TODO: ConstantValue Attributes (final)
         // TODO: Static Stuff
 
+        self.class_store.set_init(class_idx, true);
     }
 
     fn prepare_invoke_static(&mut self, class_index: usize, method_name: &String, arguments: &[Value]) -> Result<(), Error> {
@@ -210,6 +212,17 @@ impl JVM {
                     // TODO: Throw exception on fail
                     let callee_method_info  = &callee_class_file.methods[callee_method_index];
 
+                    if ! (callee_method_info.access_flags & MethodAccessFlag::Static) {
+                        // TODO: Throw IncompatibleClassChangeError
+                        return Err(Error::RunTimeError(format!(
+                                    "Invoked method '{}' in class '{}' does not have Access::Static (from invokestatic from '{}' in class '{}')",
+                                    method.name,
+                                    class.get_classname().unwrap(),
+                                    supplied_method_name,
+                                    supplied_class_name,
+                                    )));
+                    }
+
                     let supplied_descriptor: MethodDescriptor = supplied_descriptor_string.try_into()?;
                     // TODO: Throw exception on fail
 
@@ -225,6 +238,7 @@ impl JVM {
                     }
 
                     let arguments = Vec::new();
+                    // TODO: Pass arguments
 
                     let new_frame = StackFrame::new(
                         callee_class_file,
@@ -233,11 +247,22 @@ impl JVM {
                         &arguments.into_boxed_slice(),
                     );
 
-                    //println!("{} {} {}", class_name, method_name, method_descriptor);
-
                     return Ok(JVMCallbackOperation::PushFrame(new_frame));
                 },
 
+                Instruction::ReturnVoid() => {
+                    let expected_type = AbstractTypeDescription {
+                        array_level: 0,
+                        kind: AbstractTypeKind::Void(),
+                    };
+
+                    if method.descriptor.return_type != expected_type {
+                        return Err(Error::OpcodeError(format!("Found opcode '{:?}' on method returning '{:?}'", instruction, method.descriptor.return_type)))
+                    }
+
+                    return Ok(JVMCallbackOperation::PopFrame());
+                },
+
                 _ => {
                     return Err(Error::RunTimeError(format!("Opcode not implemented yet: {:?}", instruction)))
                 },