Remove magic numbers

Author: Adam Hrbac

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/frame/PFrame.java

@@ -76,7 +76,9 @@ public final class PFrame extends PythonBuiltinObject {
 
     // -3 for jumps not allowed, -2 for no jump, otherwise the line to jump to - only should be set
     // in a trace function.
-    private int jumpDestLine = -3;
+    public static final int DISALLOW_JUMPS = -3;
+    public static final int NO_JUMP = -2;
+    private int jumpDestLine = DISALLOW_JUMPS;
     private Object localTraceFun = null;
 
     private boolean traceLine = true;
@@ -100,7 +102,7 @@ public void setTraceLine(boolean traceLine) {
     }
 
     public boolean isTraceArgument() {
-        return jumpDestLine != -3;
+        return jumpDestLine != DISALLOW_JUMPS;
     }
 
     public int getJumpDestLine() {
@@ -244,7 +246,7 @@ public void lineUnlock() {
     }
 
     public boolean didJump() {
-        return jumpDestLine > -2;
+        return jumpDestLine > NO_JUMP;
     }
 
     @TruffleBoundary

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/nodes/bytecode/PBytecodeRootNode.java

@@ -2929,15 +2929,17 @@ private int traceLine(VirtualFrame virtualFrame, MutableLoopData mutableData, by
                 return bci;
             }
             if (pyFrame.getTraceLine()) {
-                pyFrame.setJumpDestLine(-2);
+                pyFrame.setJumpDestLine(PFrame.NO_JUMP); // jumps from live event allowed
                 invokeTraceFunction(virtualFrame, null, mutableData.getThreadState(this), mutableData, PythonContext.TraceEvent.LINE,
                                 mutableData.getPastLine(), true);
                 if (pyFrame.didJump()) {
                     int newBci = lineToBci(pyFrame.getJumpDestLine());
                     mutableData.setPastBci(bci);
                     if (newBci == -1) {
+                        // line before the code block
                         throw PRaiseNode.getUncached().raise(ValueError, ErrorMessages.LINE_D_COMES_AFTER_THE_CURRENT_CODE_BLOCK, pyFrame.getLine());
                     } else if (newBci == -2) {
+                        // line after the code block
                         throw PRaiseNode.getUncached().raise(ValueError, ErrorMessages.LINE_D_COMES_BEFORE_THE_CURRENT_CODE_BLOCK, pyFrame.getJumpDestLine());
                     } else {
                         var stacks = co.computeStackElems();
@@ -2950,7 +2952,7 @@ private int traceLine(VirtualFrame virtualFrame, MutableLoopData mutableData, by
                     }
                 }
             }
-            pyFrame.setJumpDestLine(-3);
+            pyFrame.setJumpDestLine(PFrame.DISALLOW_JUMPS);
         }
         mutableData.setPastBci(bci);
         return ret;