Bytecode DSL: fixes for the coverage package

* fix tracing: put all expressions into blocks
* co_positions return None for unavailable positions, but always something for
  each non-tracing instruction

Author: steve-s

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/code/CodeBuiltins.java

@@ -500,6 +500,8 @@ Object positions(PCode self) {
                                             // 1-based inclusive to 0-based exclusive (-1 + 1 = 0)
                                             section.getEndColumn()
                             }));
+                        } else {
+                            lines.add(PFactory.createTuple(language, new Object[]{PNone.NONE, PNone.NONE, PNone.NONE, PNone.NONE}));
                         }
                     }
                 } else {

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/compiler/bytecode_dsl/RootNodeCompiler.java

@@ -648,7 +648,7 @@ void beginTraceLineChecked(Builder b) {
     /**
      * Emits a "line" tracing if either no tracing was emitted before, or if line number was
      * updated.
-     * 
+     *
      * @param b Builder for line tracing.
      */
     void endTraceLineChecked(SSTNode node, Builder b) {
@@ -1881,6 +1881,7 @@ public void acceptBoolOpArgs(ExprTy.BoolOp node) {
         @Override
         public Void visit(ExprTy.BoolOp node) {
             boolean newStatement = beginSourceSection(node, b);
+            b.beginBlock();
             emitTraceLineChecked(node, b);
 
             if (node.op == BoolOpTy.And) {
@@ -1897,6 +1898,7 @@ public Void visit(ExprTy.BoolOp node) {
                 b.endBoolOr();
             }
 
+            b.endBlock();
             endSourceSection(b, newStatement);
             return null;
         }
@@ -2053,9 +2055,11 @@ private void emitGetMethod(ExprTy func, BytecodeLocal receiver) {
         @Override
         public Void visit(ExprTy.Call node) {
             boolean newStatement = beginSourceSection(node, b);
+            b.beginBlock();
             emitTraceLineChecked(node, b);
             checkCaller(ctx.errorCallback, node.func);
             emitCall(node.func, node.args, node.keywords);
+            b.endBlock();
             endSourceSection(b, newStatement);
             return null;
         }
@@ -2832,6 +2836,7 @@ public void emitYieldFrom(Runnable generatorOrCoroutineProducer, BytecodeLocal r
              *   except Exception as e:
              *     # throw/close generator
              *     if generator returned a value:
+             *       returnValue = e.value
              *       goto end
              *     else:
              *       continue (generator yielded a value)
@@ -2843,7 +2848,7 @@ public void emitYieldFrom(Runnable generatorOrCoroutineProducer, BytecodeLocal r
              *     returnValue = e.value
              *     goto end
              *
-             * end: # Step 4: resultValue local is assigned
+             * end: # Step 4: returnValue local is assigned
              * @formatter:on
              */
             BytecodeLocal generator = b.createLocal();
@@ -4383,6 +4388,7 @@ private void visitMatchCaseRecursively(MatchCaseTy[] cases, int index, PatternCo
              */
             MatchCaseTy c = cases[index];
             boolean newStatement = beginSourceSection(c, b);
+            b.beginBlock();
             emitTraceLineChecked(cases[index], b);
 
             if (index != cases.length - 1) {
@@ -4415,6 +4421,7 @@ private void visitMatchCaseRecursively(MatchCaseTy[] cases, int index, PatternCo
                 }
             }
 
+            b.endBlock();
             endSourceSection(b, newStatement);
         }
 
@@ -4486,6 +4493,7 @@ private void emitPatternCondition(MatchCaseTy currentCase, PatternContext pc) {
          */
         private void visitPattern(PatternTy pattern, PatternContext pc) {
             boolean newStatement = beginSourceSection(pattern, b);
+            b.beginBlock();
             emitTraceLineChecked(pattern, b);
             if (pattern instanceof PatternTy.MatchAs matchAs) {
                 doVisitPattern(matchAs, pc);
@@ -4506,6 +4514,7 @@ private void visitPattern(PatternTy pattern, PatternContext pc) {
             } else {
                 throw CompilerDirectives.shouldNotReachHere();
             }
+            b.endBlock();
             endSourceSection(b, newStatement);
         }
 

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/exception/ExceptionUtils.java

@@ -137,7 +137,10 @@ private static int getLineno(Frame frame, Node location, FrameInstance frameInst
 
                 if (bytecodeNode != null) {
                     int bci = bytecodeNode.getBytecodeIndex(frame);
-                    return bytecodeNode.getBytecodeLocation(bci).getSourceLocation().getStartLine();
+                    SourceSection sourceLocation = bytecodeNode.getBytecodeLocation(bci).getSourceLocation();
+                    if (sourceLocation != null) {
+                        return sourceLocation.getStartLine();
+                    }
                 }
             } else {
                 return ((BytecodeFrameInfo) frameInfo).getLine(frame);