Don't reset stackframes at function bridges (#1145)

Author: Frotty

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/translation/imtranslation/StackTraceInjector2.java

@@ -380,14 +380,15 @@ private void rewriteFuncRefs(final List<ImFuncRefOrCall> funcRefs, Set<ImFunctio
             ImExprs args = JassIm.ImExprs(str);
             ImStmts body = bridgeFunc.getBody();
             de.peeeq.wurstscript.ast.Element trace = frTrace;
-            // reset stack and add information for callback:
-            body.add(JassIm.ImSet(trace, JassIm.ImVarAccess(stackSize), JassIm.ImIntVal(0)));
 
             ImFunctionCall call = JassIm.ImFunctionCall(frTrace, f, JassIm.ImTypeArguments(), args, true, CallType.NORMAL);
             if (bridgeFunc.getReturnType() instanceof ImVoid) {
                 stmt = call;
             } else {
-                stmt = JassIm.ImReturn(frTrace, call);
+                ImVar bridgeReturn = JassIm.ImVar(trace, bridgeFunc.getReturnType().copy(), "bridge_return", false);
+                bridgeFunc.getLocals().add(bridgeReturn);
+                body.add(JassIm.ImSet(trace, JassIm.ImVarAccess(bridgeReturn), call));
+                stmt = JassIm.ImReturn(frTrace, JassIm.ImVarAccess(bridgeReturn));
             }
             body.add(stmt);
 
@@ -426,7 +427,7 @@ private void rewriteErrorStatements(final Multimap<ImFunction, ImGetStackTrace>
             ImVar traceLimit = JassIm.ImVar(trace, TypesHelper.imInt(), "stacktraceLimit", false);
             f.getLocals().add(traceLimit);
             ImStmts stmts = JassIm.ImStmts();
-            stmts.add(JassIm.ImSet(trace, JassIm.ImVarAccess(traceStr), JassIm.ImStringVal("")));
+            stmts.add(JassIm.ImSet(trace, JassIm.ImVarAccess(traceStr), JassIm.ImStringVal(" Stacktrace:")));
             stmts.add(JassIm.ImSet(trace, JassIm.ImVarAccess(traceI), JassIm.ImVarAccess(stackSize)));
             stmts.add(JassIm.ImSet(trace, JassIm.ImVarAccess(traceLimit), JassIm.ImIntVal(0)));
             ImStmts loopBody = JassIm.ImStmts();
@@ -447,6 +448,12 @@ private void rewriteErrorStatements(final Multimap<ImFunction, ImGetStackTrace>
                     JassIm.ImOperatorCall(WurstOperator.PLUS, JassIm.ImExprs(JassIm.ImStringVal("\n   "),
                         JassIm.ImVarArrayAccess(trace, stack, JassIm.ImExprs(JassIm.ImVarAccess(traceI)))))))));
 
+            // Make empty traces explicit instead of returning an empty string.
+            stmts.add(JassIm.ImIf(trace, JassIm.ImOperatorCall(WurstOperator.EQ,
+                    JassIm.ImExprs(JassIm.ImVarAccess(traceStr), JassIm.ImStringVal(" Stacktrace:"))),
+                JassIm.ImStmts(JassIm.ImSet(trace, JassIm.ImVarAccess(traceStr), JassIm.ImStringVal(" Stacktrace: <none>"))),
+                JassIm.ImStmts()));
+
             s.replaceBy(JassIm.ImStatementExpr(stmts, JassIm.ImVarAccess(traceStr)));
         }
     }

de.peeeq.wurstscript/src/test/java/tests/wurstscript/tests/BugTests.java

@@ -1,5 +1,7 @@
 package tests.wurstscript.tests;
 
+import com.google.common.base.Charsets;
+import com.google.common.io.Files;
 import de.peeeq.wurstio.jassinterpreter.InterpreterException;
 import de.peeeq.wurstscript.ast.ClassDef;
 import de.peeeq.wurstscript.ast.FuncDef;
@@ -1070,6 +1072,18 @@ public void testStacktrace() {
                 "    if foo(bar(1), bar(2))",
                 "        testSuccess()"
         );
+
+        try {
+            String jass = Files.toString(
+                new File(TEST_OUTPUT_PATH + "BugTests_testStacktrace_stacktraceinlopt.j"),
+                Charsets.UTF_8
+            );
+            Assert.assertTrue(jass.contains("wurst_stack_depth"));
+            Assert.assertTrue(jass.contains("wurst_stack"));
+            Assert.assertFalse(jass.contains("return \"\""));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     @Test
@@ -1450,6 +1464,37 @@ public void executeFuncWithStackTrace() {
         );
     }
 
+    @Test
+    public void executeFuncBridgeKeepsCallerStackFrames() {
+        test().executeProg(false).executeTests(false).lines(
+            "package Test",
+            "@extern native ExecuteFunc(string f)",
+            "function getStackTraceString() returns string",
+            "    return \"\"",
+            "function foo()",
+            "    getStackTraceString()",
+            "function caller()",
+            "    getStackTraceString()",
+            "    ExecuteFunc(\"foo\")",
+            "    getStackTraceString()",
+            "init",
+            "    caller()"
+        );
+
+        try {
+            String jass = Files.toString(
+                new File(TEST_OUTPUT_PATH + "BugTests_executeFuncBridgeKeepsCallerStackFrames_stacktraceinlopt.j"),
+                Charsets.UTF_8
+            );
+            Assert.assertTrue(jass.contains("function bridge_foo"));
+            Assert.assertFalse(jass.contains("bridge_oldStackDepth"));
+            Assert.assertFalse(jass.contains("set wurst_stack_depth = 0"));
+            Assert.assertTrue(jass.contains("via ExecuteFunc"));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
     @Test
     public void agentTypeComparisonsWurst() {
         testAssertErrorsLinesWithStdLib(true, "Cannot compare types sound with rect",