Add basic disassembly view (#5)

* Add basic disassembly view, highlights the currently active line when created

Currently, the window does not automatically update if the pc changes.

* Register a listener when opening the disassembly window

* Strip away part of the wasm-objdump output + enable assembler syntax highlighting

It's not wasm highlighting, but it does work reasonably well.

* Move disassembly view into a class + properly remove listener when closing the window

* Show an error message when wabt is not installed

Author: MaartenS11

src/main/kotlin/be/ugent/topl/mio/debugger/Debugger.kt

@@ -103,8 +103,8 @@ open class Debugger(private val connection: Connection, start: Boolean = true, p
             }
         }
     }
-    val history = mutableListOf<WOODDumpResponse>()
     val checkpoints = mutableListOf<Checkpoint?>()
+    private val stateListeners = mutableListOf<(WOODDumpResponse) -> Unit>()
     private var commandBreakpoint = false
 
     init {
@@ -310,7 +310,26 @@ open class Debugger(private val connection: Connection, start: Boolean = true, p
         // Results:
         checkpointsUpdated()
     }
-    open fun checkpointsUpdated() {}
+
+    open fun checkpointsUpdated() {
+        val currentState = checkpoints.last()
+        if (currentState == null) {
+            return
+        }
+
+        for (listener in stateListeners) {
+            listener(currentState.snapshot)
+        }
+    }
+
+    fun registerCurrentStateListener(listener: (WOODDumpResponse) -> Unit) {
+        stateListeners.add(listener)
+    }
+
+    fun removeCurrentStateListener(listener: (WOODDumpResponse) -> Unit) {
+        stateListeners.remove(listener)
+    }
+
     fun addBreakpoint(address: Int) {
         send(6, String.format("%08x", address))
         messageQueue.waitForResponse("BP $address!")

src/main/kotlin/be/ugent/topl/mio/ui/DisassemblyWindow.kt

@@ -0,0 +1,67 @@
+package be.ugent.topl.mio.ui
+
+import be.ugent.topl.mio.debugger.Debugger
+import be.ugent.topl.mio.woodstate.WOODDumpResponse
+import com.formdev.flatlaf.FlatLaf
+import org.fife.ui.rsyntaxtextarea.RSyntaxTextArea
+import org.fife.ui.rsyntaxtextarea.SyntaxConstants
+import org.fife.ui.rtextarea.RTextScrollPane
+import java.awt.Color
+import java.awt.Dimension
+import java.awt.event.WindowAdapter
+import java.awt.event.WindowEvent
+import java.io.IOException
+import javax.swing.JFrame
+
+class DisassemblyWindow(debugger: Debugger, wasmFile: String) : JFrame("Disassembly") {
+    private val disassemblyTextArea = RSyntaxTextArea(disassemble(wasmFile)).apply {
+        syntaxEditingStyle = SyntaxConstants.SYNTAX_STYLE_ASSEMBLER_X86
+        isEditable = false
+    }
+
+    init {
+        add(RTextScrollPane(disassemblyTextArea))
+        minimumSize = Dimension(200, 200)
+        preferredSize = Dimension(400, 600)
+        isVisible = true
+
+        highlightCurrentLine(debugger.checkpoints.last()!!.snapshot)
+
+        val listener = this::highlightCurrentLine
+        addWindowListener(object : WindowAdapter() {
+            override fun windowClosing(e: WindowEvent?) {
+                debugger.removeCurrentStateListener(listener)
+            }
+        })
+        debugger.registerCurrentStateListener(listener)
+    }
+
+    private fun disassemble(wasmFile: String): String {
+        try {
+            val command = listOf("wasm-objdump", "-d", wasmFile)
+            println("Running command: ${command.joinToString(" ")}")
+            val process = ProcessBuilder(command).redirectErrorStream(true).start()
+            process.waitFor()
+            var result = process.inputStream.readAllBytes().toString(Charsets.UTF_8)
+            val startString = "Code Disassembly:\n\n"
+            return result.substring(result.indexOf(startString) + startString.length)
+        } catch (e: IOException) {
+            // Catch exception and add additional information.
+            throw IOException("An error occurred when attempting to disassemble the program, make sure the The WebAssembly Binary Toolkit is installed on your system.\n" + e.message)
+        }
+    }
+
+    private fun highlightCurrentLine(currentState: WOODDumpResponse) {
+        // IDEA: Would maybe be fun to highlight the instructions associated with the current line with the same color.
+        val pc = currentState.pc!!
+        val lines = disassemblyTextArea.text.lines()
+        for (lineIndex in lines.indices) {
+            val line = lines[lineIndex]
+            // TODO: Use binary search instead of just linearly searching the address
+            if (line.trim().startsWith(String.format("%06x", pc))) {
+                disassemblyTextArea.removeAllLineHighlights()
+                disassemblyTextArea.addLineHighlight(lineIndex, if (!FlatLaf.isLafDark()) Color(255, 255, 186, 255) else Color(207, 207, 131, 75))
+            }
+        }
+    }
+}

src/main/kotlin/be/ugent/topl/mio/ui/InteractiveDebugger.kt

@@ -26,6 +26,7 @@ import java.awt.event.MouseListener
 import java.awt.event.WindowAdapter
 import java.awt.event.WindowEvent
 import java.io.File
+import java.io.IOException
 import javax.swing.*
 import javax.swing.event.DocumentEvent
 import javax.swing.event.DocumentListener
@@ -276,6 +277,15 @@ class InteractiveDebugger(
         textArea.isEditable = false
         textArea.text = sourceMapping?.getSourceFile(0) ?: "Source mapping unavailable"
         textArea.syntaxEditingStyle = sourceMapping?.getStyle() ?: SyntaxConstants.SYNTAX_STYLE_ASSEMBLER_X86
+        textArea.popupMenu.add(JMenuItem("Disassemble").apply {
+            addActionListener {
+                try {
+                    DisassemblyWindow(debugger, wasmFile)
+                } catch(e: IOException) {
+                    JOptionPane.showMessageDialog(null, e.message, "Error", JOptionPane.ERROR_MESSAGE)
+                }
+            }
+        })
         scrollPane.isIconRowHeaderEnabled = true
         scrollPane.gutter.iconRowHeaderInheritsGutterBackground = true
         if (sourceMapping != null) {
@@ -757,6 +767,9 @@ class WatchWindow : JTable() {
         for (global in snapshot.globals!!) {
             tableModel.addRow(arrayOf("global ${global.idx}", global.type, global.value))
         }
+        if (snapshot.callstack!!.isNotEmpty()) {
+            tableModel.addRow(arrayOf("fp", "i32", snapshot.callstack.last().fp))
+        }
         val stack = snapshot.stack!!
         for (stackElement in stack) {
             tableModel.addRow(arrayOf("stack[${stackElement.idx}]", stackElement.type, stackElement.value))