Reserve preserved names during compression

Author: Frotty

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/translation/imoptimizer/ImCompressor.java

@@ -7,16 +7,30 @@
 import de.peeeq.wurstscript.translation.imtranslation.ImTranslator;
 import de.peeeq.wurstscript.validation.NamePreservation;
 
+import java.util.HashSet;
+import java.util.Set;
+
 public class ImCompressor {
 
     private final ImTranslator trans;
     private final ImProg prog;
     private final NameGenerator ng;
+    private final Set<String> preservedNames = new HashSet<>();
 
     public ImCompressor(ImTranslator translator) {
         this.trans = translator;
         this.prog = translator.getImProg();
         ng = new NameGenerator();
+        for (ImVar global : prog.getGlobals()) {
+            if (NamePreservation.isPreserved(global)) {
+                preservedNames.add(global.getName());
+            }
+        }
+        for (ImFunction function : ImHelper.calculateFunctionsOfProg(prog)) {
+            if (NamePreservation.isPreserved(function)) {
+                preservedNames.add(function.getName());
+            }
+        }
     }
 
     public void compressNames() {
@@ -32,7 +46,7 @@ public void compressGlobals() {
                 continue;
             }
 
-            String replacement = ng.getUniqueToken();
+            String replacement = nextCompressedName();
 
             global.setName(replacement);
         }
@@ -50,12 +64,20 @@ public void compressFunctions() {
                 // do not rename main and config functions
                 continue;
             }
-            String rname = ng.getUniqueToken();
+            String rname = nextCompressedName();
             func.setName(rname);
         }
 
     }
 
+    private String nextCompressedName() {
+        String replacement;
+        do {
+            replacement = ng.getUniqueToken();
+        } while (preservedNames.contains(replacement));
+        return replacement;
+    }
+
     private void compressLocals(ImFunction func) {
         // TODO compressing locals should not use the global name pool but use a own pool
         for (ImVar local : func.getParameters()) {

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/translation/lua/translation/LuaTranslator.java

@@ -492,7 +492,8 @@ private boolean isFixedEntryPoint(ImFunction function) {
 
     private void collectPredefinedNames() {
         for (ImFunction function : prog.getFunctions()) {
-            if (function.isBj() || function.isExtern() || function.isNative()) {
+            if (function.isBj() || function.isExtern() || function.isNative()
+                || NamePreservation.isPreserved(function)) {
                 // Don't rename Wurst-internal stubs (names starting with __wurst_)
                 // since their names are intentionally different from their trace's source name.
                 if (!function.getName().startsWith("__wurst_")) {
@@ -506,6 +507,8 @@ private void collectPredefinedNames() {
             if (global.getIsBJ()) {
                 setNameFromTrace(global);
                 usedNames.add(global.getName());
+            } else if (NamePreservation.isPreserved(global)) {
+                usedNames.add(global.getName());
             }
         }
     }

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

@@ -504,6 +504,29 @@ public void preserveNameAnnotationKeepsExternallyCalledFunctionReachable() throw
             "Expected an externally-called @preserveName function to survive garbage collection.\n" + output);
     }
 
+    @Test
+    public void preservedNamesAreReservedBeforeCompression() throws IOException {
+        test().optimize().lines(
+            "package test",
+            "    native testSuccess()",
+            "    function ordinary()",
+            "        testSuccess()",
+            "    @preserveName function w()",
+            "        testSuccess()",
+            "    init",
+            "        ordinary()",
+            "        w()",
+            "endpackage");
+
+        String output = Files.toString(
+            new File("./test-output/OptimizerTests_preservedNamesAreReservedBeforeCompression_opt.j"),
+            Charsets.UTF_8);
+        assertTrue(output.contains("function w"),
+            "Expected the preserved function name to remain available.\n" + output);
+        assertFalse(output.contains("function w_1"),
+            "Expected compression to reserve the preserved name.\n" + output);
+    }
+
     @Test
     public void trvePreservesGlobalDespiteLexicalShadow() throws IOException {
         test().optimize().lines(