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| 1 | +package de.peeeq.wurstscript.translation.imtranslation; |
| 2 | + |
| 3 | +import de.peeeq.wurstscript.WurstOperator; |
| 4 | +import de.peeeq.wurstscript.jassIm.*; |
| 5 | + |
| 6 | +import java.util.*; |
| 7 | + |
| 8 | +/** |
| 9 | + * IM-level lowering pass for the Lua backend, run before optimization so the |
| 10 | + * optimizer can inline and eliminate the generated wrappers. |
| 11 | + * |
| 12 | + * <p>Three classes of WC3 BJ calls are transformed: |
| 13 | + * <ol> |
| 14 | + * <li><b>GetHandleId</b> – replaced 1:1 by {@code __wurst_GetHandleId}, whose Lua |
| 15 | + * implementation uses a stable table counter instead of the WC3 handle ID |
| 16 | + * (which can desync in Lua mode).</li> |
| 17 | + * <li><b>Hashtable natives</b> ({@code SaveInteger}, {@code LoadBoolean}, …) and |
| 18 | + * <b>context-callback natives</b> ({@code ForForce}, {@code ForGroup}, …) – |
| 19 | + * replaced 1:1 by their {@code __wurst_} prefixed equivalents, whose Lua |
| 20 | + * implementations are provided by {@link de.peeeq.wurstscript.translation.lua.translation.LuaNatives}.</li> |
| 21 | + * <li><b>All other BJ calls with at least one handle-typed parameter</b> – wrapped |
| 22 | + * by a generated IM function that first checks each handle param for {@code null} |
| 23 | + * and returns the type-appropriate default (0 / 0.0 / false / "" / nil), then |
| 24 | + * delegates to the original BJ function. This matches Jass behavior, which |
| 25 | + * silently returns defaults on null-handle calls instead of crashing.</li> |
| 26 | + * </ol> |
| 27 | + * |
| 28 | + * <p>IS_NATIVE stubs added for category 1 and 2 are recognised by |
| 29 | + * {@link de.peeeq.wurstscript.translation.lua.translation.LuaTranslator#translateFunc} as |
| 30 | + * Wurst-owned natives and filled in by |
| 31 | + * {@link de.peeeq.wurstscript.translation.lua.translation.LuaNatives}. |
| 32 | + */ |
| 33 | +public final class LuaNativeLowering { |
| 34 | + |
| 35 | + /** Hashtable native names that need to be remapped to {@code __wurst_} equivalents. */ |
| 36 | + private static final Set<String> HASHTABLE_NATIVE_NAMES = new HashSet<>(Arrays.asList( |
| 37 | + "InitHashtable", |
| 38 | + "SaveInteger", "SaveBoolean", "SaveReal", "SaveStr", |
| 39 | + "LoadInteger", "LoadBoolean", "LoadReal", "LoadStr", |
| 40 | + "HaveSavedInteger", "HaveSavedBoolean", "HaveSavedReal", "HaveSavedString", "HaveSavedHandle", |
| 41 | + "FlushChildHashtable", "FlushParentHashtable", |
| 42 | + "RemoveSavedInteger", "RemoveSavedBoolean", "RemoveSavedReal", "RemoveSavedString", "RemoveSavedHandle", |
| 43 | + // Handle-typed save/load variants |
| 44 | + "SavePlayerHandle", "SaveWidgetHandle", "SaveDestructableHandle", "SaveItemHandle", "SaveUnitHandle", |
| 45 | + "SaveAbilityHandle", "SaveTimerHandle", "SaveTriggerHandle", "SaveTriggerConditionHandle", |
| 46 | + "SaveTriggerActionHandle", "SaveTriggerEventHandle", "SaveForceHandle", "SaveGroupHandle", |
| 47 | + "SaveLocationHandle", "SaveRectHandle", "SaveBooleanExprHandle", "SaveSoundHandle", "SaveEffectHandle", |
| 48 | + "SaveUnitPoolHandle", "SaveItemPoolHandle", "SaveQuestHandle", "SaveQuestItemHandle", |
| 49 | + "SaveDefeatConditionHandle", "SaveTimerDialogHandle", "SaveLeaderboardHandle", "SaveMultiboardHandle", |
| 50 | + "SaveMultiboardItemHandle", "SaveTrackableHandle", "SaveDialogHandle", "SaveButtonHandle", |
| 51 | + "SaveTextTagHandle", "SaveLightningHandle", "SaveImageHandle", "SaveUbersplatHandle", "SaveRegionHandle", |
| 52 | + "SaveFogStateHandle", "SaveFogModifierHandle", "SaveAgentHandle", "SaveHashtableHandle", "SaveFrameHandle", |
| 53 | + "LoadPlayerHandle", "LoadWidgetHandle", "LoadDestructableHandle", "LoadItemHandle", "LoadUnitHandle", |
| 54 | + "LoadAbilityHandle", "LoadTimerHandle", "LoadTriggerHandle", "LoadTriggerConditionHandle", |
| 55 | + "LoadTriggerActionHandle", "LoadTriggerEventHandle", "LoadForceHandle", "LoadGroupHandle", |
| 56 | + "LoadLocationHandle", "LoadRectHandle", "LoadBooleanExprHandle", "LoadSoundHandle", "LoadEffectHandle", |
| 57 | + "LoadUnitPoolHandle", "LoadItemPoolHandle", "LoadQuestHandle", "LoadQuestItemHandle", |
| 58 | + "LoadDefeatConditionHandle", "LoadTimerDialogHandle", "LoadLeaderboardHandle", "LoadMultiboardHandle", |
| 59 | + "LoadMultiboardItemHandle", "LoadTrackableHandle", "LoadDialogHandle", "LoadButtonHandle", |
| 60 | + "LoadTextTagHandle", "LoadLightningHandle", "LoadImageHandle", "LoadUbersplatHandle", "LoadRegionHandle", |
| 61 | + "LoadFogStateHandle", "LoadFogModifierHandle", "LoadHashtableHandle", "LoadFrameHandle" |
| 62 | + )); |
| 63 | + |
| 64 | + /** Context-callback natives that need to be remapped to {@code __wurst_} equivalents. */ |
| 65 | + private static final Set<String> CONTEXT_CALLBACK_NATIVE_NAMES = new HashSet<>(Arrays.asList( |
| 66 | + "ForForce", "GetEnumPlayer", |
| 67 | + "ForGroup", "GetEnumUnit", |
| 68 | + "EnumItemsInRect", "GetEnumItem", |
| 69 | + "EnumDestructablesInRect", "GetEnumDestructable" |
| 70 | + )); |
| 71 | + |
| 72 | + private LuaNativeLowering() {} |
| 73 | + |
| 74 | + /** |
| 75 | + * Transforms the IM program in place. |
| 76 | + * |
| 77 | + * <p>Must be called <em>before</em> the optimizer so that the optimizer |
| 78 | + * can inline and eliminate the generated wrappers. |
| 79 | + * |
| 80 | + * <p>Stubs and wrappers are created lazily (on first call-site encounter) and added |
| 81 | + * to prog only after the traversal completes. This avoids the memory cost of |
| 82 | + * creating wrappers for every BJ function in the IM (common.j declares hundreds of |
| 83 | + * functions, most of which are unreachable in any given program). |
| 84 | + */ |
| 85 | + public static void transform(ImProg prog) { |
| 86 | + // Replace all reads of MagicFunctions_isLua with true. |
| 87 | + // This must happen before any optimizer passes so that dead-code elimination |
| 88 | + // can remove Jass-only branches at compile time. |
| 89 | + // We use attrReads() (not a visitor) to target only rvalue uses, avoiding |
| 90 | + // ClassCastException when the same ImVarAccess appears as a write target (lvalue). |
| 91 | + for (ImVar global : prog.getGlobals()) { |
| 92 | + if ("MagicFunctions_isLua".equals(global.getName())) { |
| 93 | + for (ImVarRead read : new ArrayList<>(global.attrReads())) { |
| 94 | + read.replaceBy(JassIm.ImBoolVal(true)); |
| 95 | + } |
| 96 | + break; |
| 97 | + } |
| 98 | + } |
| 99 | + |
| 100 | + // Maps original BJ function → replacement (IS_NATIVE stub or nil-safety wrapper). |
| 101 | + // Populated lazily during the traversal. |
| 102 | + Map<ImFunction, ImFunction> replacements = new LinkedHashMap<>(); |
| 103 | + // BJ functions that don't need a replacement (not GetHandleId, not hashtable/callback, |
| 104 | + // no handle params). Cached to avoid rechecking the same function at every call site. |
| 105 | + Set<ImFunction> noReplacement = new HashSet<>(); |
| 106 | + // All generated functions (stubs and wrappers) are deferred until after the traversal: |
| 107 | + // - Stubs: deferred so ConcurrentModificationException is avoided on prog.getFunctions() |
| 108 | + // - Wrappers: deferred so the visitor doesn't see their internal BJ delegate calls and |
| 109 | + // recursively wrap them, which would cause infinite wrapping. |
| 110 | + List<ImFunction> deferredAdditions = new ArrayList<>(); |
| 111 | + |
| 112 | + prog.accept(new Element.DefaultVisitor() { |
| 113 | + @Override |
| 114 | + public void visit(ImFunctionCall call) { |
| 115 | + super.visit(call); |
| 116 | + ImFunction f = call.getFunc(); |
| 117 | + if (!f.isBj()) return; |
| 118 | + if (noReplacement.contains(f)) return; |
| 119 | + |
| 120 | + if (!replacements.containsKey(f)) { |
| 121 | + ImFunction r = computeReplacement(f); |
| 122 | + if (r != null) { |
| 123 | + replacements.put(f, r); |
| 124 | + deferredAdditions.add(r); |
| 125 | + } else { |
| 126 | + noReplacement.add(f); |
| 127 | + } |
| 128 | + } |
| 129 | + ImFunction replacement = replacements.get(f); |
| 130 | + |
| 131 | + if (replacement != null) { |
| 132 | + call.replaceBy(JassIm.ImFunctionCall( |
| 133 | + call.attrTrace(), replacement, |
| 134 | + JassIm.ImTypeArguments(), |
| 135 | + call.getArguments().copy(), |
| 136 | + false, CallType.NORMAL)); |
| 137 | + } |
| 138 | + } |
| 139 | + |
| 140 | + private ImFunction computeReplacement(ImFunction bj) { |
| 141 | + String name = bj.getName(); |
| 142 | + if ("GetHandleId".equals(name)) { |
| 143 | + return createNativeStub("__wurst_GetHandleId", bj); |
| 144 | + } else if (HASHTABLE_NATIVE_NAMES.contains(name)) { |
| 145 | + return createNativeStub("__wurst_" + name, bj); |
| 146 | + } else if (CONTEXT_CALLBACK_NATIVE_NAMES.contains(name)) { |
| 147 | + return createNativeStub("__wurst_" + name, bj); |
| 148 | + } else if (hasHandleParam(bj)) { |
| 149 | + return createNilSafeWrapper(bj); |
| 150 | + } |
| 151 | + return null; |
| 152 | + } |
| 153 | + }); |
| 154 | + |
| 155 | + // Add all generated functions after the traversal so their bodies are not visited |
| 156 | + // by the replacement visitor above. |
| 157 | + prog.getFunctions().addAll(deferredAdditions); |
| 158 | + } |
| 159 | + |
| 160 | + /** |
| 161 | + * Creates a new IS_NATIVE (non-BJ) IM function stub with the same signature as |
| 162 | + * {@code original}. The Lua translator will fill in the body via |
| 163 | + * {@code LuaNatives.get()} when it encounters the stub. |
| 164 | + * |
| 165 | + * <p>The caller is responsible for adding the stub to prog.getFunctions(). |
| 166 | + */ |
| 167 | + private static ImFunction createNativeStub(String name, ImFunction original) { |
| 168 | + ImVars params = JassIm.ImVars(); |
| 169 | + for (ImVar p : original.getParameters()) { |
| 170 | + params.add(JassIm.ImVar(p.attrTrace(), p.getType().copy(), p.getName(), false)); |
| 171 | + } |
| 172 | + return JassIm.ImFunction( |
| 173 | + original.attrTrace(), name, |
| 174 | + JassIm.ImTypeVars(), params, |
| 175 | + original.getReturnType().copy(), |
| 176 | + JassIm.ImVars(), JassIm.ImStmts(), |
| 177 | + Collections.singletonList(FunctionFlagEnum.IS_NATIVE)); |
| 178 | + } |
| 179 | + |
| 180 | + /** |
| 181 | + * Creates a nil-safety wrapper for {@code bjNative}. |
| 182 | + * |
| 183 | + * <p>The generated function checks each handle-typed parameter against |
| 184 | + * {@code null} and returns the type-appropriate default value if any is |
| 185 | + * null. Otherwise it delegates to the original BJ function. |
| 186 | + */ |
| 187 | + private static ImFunction createNilSafeWrapper(ImFunction bjNative) { |
| 188 | + ImVars params = JassIm.ImVars(); |
| 189 | + List<ImVar> paramVars = new ArrayList<>(); |
| 190 | + for (ImVar p : bjNative.getParameters()) { |
| 191 | + ImVar copy = JassIm.ImVar(p.attrTrace(), p.getType().copy(), p.getName(), false); |
| 192 | + params.add(copy); |
| 193 | + paramVars.add(copy); |
| 194 | + } |
| 195 | + |
| 196 | + ImStmts body = JassIm.ImStmts(); |
| 197 | + |
| 198 | + // Null-check each handle param: if param == null then return <default> end |
| 199 | + ImExpr returnDefault = defaultValueExpr(bjNative.getReturnType()); |
| 200 | + for (ImVar param : paramVars) { |
| 201 | + if (isHandleType(param.getType())) { |
| 202 | + ImExpr condition = JassIm.ImOperatorCall(WurstOperator.EQ, JassIm.ImExprs( |
| 203 | + JassIm.ImVarAccess(param), |
| 204 | + JassIm.ImNull(param.getType().copy()) |
| 205 | + )); |
| 206 | + ImStmts thenBlock = JassIm.ImStmts( |
| 207 | + JassIm.ImReturn(bjNative.attrTrace(), returnDefault.copy()) |
| 208 | + ); |
| 209 | + body.add(JassIm.ImIf(bjNative.attrTrace(), condition, thenBlock, JassIm.ImStmts())); |
| 210 | + } |
| 211 | + } |
| 212 | + |
| 213 | + // Delegate to the original BJ native |
| 214 | + ImExprs callArgs = JassIm.ImExprs(); |
| 215 | + for (ImVar pv : paramVars) { |
| 216 | + callArgs.add(JassIm.ImVarAccess(pv)); |
| 217 | + } |
| 218 | + ImFunctionCall delegate = JassIm.ImFunctionCall( |
| 219 | + bjNative.attrTrace(), bjNative, |
| 220 | + JassIm.ImTypeArguments(), callArgs, false, CallType.NORMAL); |
| 221 | + |
| 222 | + if (bjNative.getReturnType() instanceof ImVoid) { |
| 223 | + body.add(delegate); |
| 224 | + } else { |
| 225 | + body.add(JassIm.ImReturn(bjNative.attrTrace(), delegate)); |
| 226 | + } |
| 227 | + |
| 228 | + return JassIm.ImFunction( |
| 229 | + bjNative.attrTrace(), |
| 230 | + "__wurst_safe_" + bjNative.getName(), |
| 231 | + JassIm.ImTypeVars(), params, |
| 232 | + bjNative.getReturnType().copy(), |
| 233 | + JassIm.ImVars(), body, |
| 234 | + Collections.emptyList()); |
| 235 | + } |
| 236 | + |
| 237 | + private static boolean hasHandleParam(ImFunction f) { |
| 238 | + for (ImVar p : f.getParameters()) { |
| 239 | + if (isHandleType(p.getType())) { |
| 240 | + return true; |
| 241 | + } |
| 242 | + } |
| 243 | + return false; |
| 244 | + } |
| 245 | + |
| 246 | + /** Returns true for WC3 handle types (ImSimpleType that is not int/real/boolean/string). */ |
| 247 | + static boolean isHandleType(ImType type) { |
| 248 | + if (!(type instanceof ImSimpleType)) { |
| 249 | + return false; |
| 250 | + } |
| 251 | + String n = ((ImSimpleType) type).getTypename(); |
| 252 | + return !n.equals("integer") && !n.equals("real") && !n.equals("boolean") && !n.equals("string"); |
| 253 | + } |
| 254 | + |
| 255 | + /** Returns an IM expression representing the safe default for the given return type. */ |
| 256 | + private static ImExpr defaultValueExpr(ImType returnType) { |
| 257 | + if (returnType instanceof ImSimpleType) { |
| 258 | + String n = ((ImSimpleType) returnType).getTypename(); |
| 259 | + switch (n) { |
| 260 | + case "integer": return JassIm.ImIntVal(0); |
| 261 | + case "real": return JassIm.ImRealVal("0.0"); |
| 262 | + case "boolean": return JassIm.ImBoolVal(false); |
| 263 | + case "string": return JassIm.ImStringVal(""); |
| 264 | + } |
| 265 | + } |
| 266 | + // void or handle type → null |
| 267 | + if (returnType instanceof ImVoid) { |
| 268 | + return JassIm.ImNull(JassIm.ImVoid()); |
| 269 | + } |
| 270 | + return JassIm.ImNull(returnType.copy()); |
| 271 | + } |
| 272 | +} |
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