Minor flow improvements (AssemblyScript#924)

Author: dcodeIO

src/compiler.ts

@@ -1288,7 +1288,7 @@ export class Compiler extends DiagnosticEmitter {
               )
             )
           );
-          flow.setLocalFlag(index, LocalFlags.RETAINED);
+          flow.setLocalFlag(index, LocalFlags.RETAINED | LocalFlags.PARAMETER);
         }
       }
 
@@ -2252,8 +2252,10 @@ export class Compiler extends DiagnosticEmitter {
       if (!this.skippedAutoreleases.has(expr)) {
         if (returnType.isManaged) {
           if (getExpressionId(expr) == ExpressionId.LocalGet) {
-            if (flow.isAnyLocalFlag(getLocalGetIndex(expr), LocalFlags.ANY_RETAINED)) {
-              flow.unsetLocalFlag(getLocalGetIndex(expr), LocalFlags.ANY_RETAINED);
+            let index = getLocalGetIndex(expr);
+            if (flow.isAnyLocalFlag(index, LocalFlags.ANY_RETAINED)) {
+              flow.unsetLocalFlag(index, LocalFlags.ANY_RETAINED);
+              flow.setLocalFlag(index, LocalFlags.RETURNED);
               this.skippedAutoreleases.add(expr);
             }
           }
@@ -6248,23 +6250,18 @@ export class Compiler extends DiagnosticEmitter {
       let initExpr = this.compileExpression(
         assert(instance.prototype.functionTypeNode.parameters[i].initializer),
         initType,
-        Constraints.CONV_IMPLICIT
+        Constraints.CONV_IMPLICIT | Constraints.WILL_RETAIN
       );
       let argumentLocal = flow.addScopedLocal(signature.getParameterName(i), initType);
       if (!flow.canOverflow(initExpr, initType)) flow.setLocalFlag(argumentLocal.index, LocalFlags.WRAPPED);
       if (flow.isNonnull(initExpr, initType)) flow.setLocalFlag(argumentLocal.index, LocalFlags.NONNULL);
       if (initType.isManaged) {
         flow.setLocalFlag(argumentLocal.index, LocalFlags.RETAINED);
-        body.push(
-          module.local_set(argumentLocal.index,
-            this.makeRetain(initExpr)
-          )
-        );
-      } else {
-        body.push(
-          module.local_set(argumentLocal.index, initExpr)
-        );
+        if (!this.skippedAutoreleases.has(initExpr)) initExpr = this.makeRetain(initExpr);
       }
+      body.push(
+        module.local_set(argumentLocal.index, initExpr)
+      );
     }
 
     // Compile the called function's body in the scope of the inlined flow

src/flow.ts

@@ -144,41 +144,58 @@ export enum LocalFlags {
 
   /** Local is constant. */
   CONSTANT = 1 << 0,
+  /** Local is a function parameter. */
+  PARAMETER = 1 << 1,
   /** Local is properly wrapped. Relevant for small integers. */
-  WRAPPED = 1 << 1,
+  WRAPPED = 1 << 2,
   /** Local is non-null. */
-  NONNULL = 1 << 2,
+  NONNULL = 1 << 3,
   /** Local is read from. */
-  READFROM = 1 << 3,
+  READFROM = 1 << 4,
   /** Local is written to. */
-  WRITTENTO = 1 << 4,
+  WRITTENTO = 1 << 5,
   /** Local is retained. */
-  RETAINED = 1 << 5,
+  RETAINED = 1 << 6,
+  /** Local is returned. */
+  RETURNED = 1 << 7,
 
   /** Local is conditionally read from. */
-  CONDITIONALLY_READFROM = 1 << 6,
+  CONDITIONALLY_READFROM = 1 << 8,
   /** Local is conditionally written to. */
-  CONDITIONALLY_WRITTENTO = 1 << 7,
+  CONDITIONALLY_WRITTENTO = 1 << 9,
   /** Local must be conditionally retained. */
-  CONDITIONALLY_RETAINED = 1 << 8,
+  CONDITIONALLY_RETAINED = 1 << 10,
+  /** Local is conditionally returned. */
+  CONDITIONALLY_RETURNED = 1 << 11,
 
   /** Any categorical flag. */
   ANY_CATEGORICAL = CONSTANT
+                  | PARAMETER
                   | WRAPPED
                   | NONNULL
                   | READFROM
                   | WRITTENTO
-                  | RETAINED,
+                  | RETAINED
+                  | RETURNED,
 
   /** Any conditional flag. */
   ANY_CONDITIONAL = RETAINED
                   | CONDITIONALLY_READFROM
                   | CONDITIONALLY_WRITTENTO
-                  | CONDITIONALLY_RETAINED,
+                  | CONDITIONALLY_RETAINED
+                  | CONDITIONALLY_RETURNED,
+
+  /** Any written to flag. */
+  ANY_WRITTENTO = WRITTENTO
+                | CONDITIONALLY_WRITTENTO,
 
   /** Any retained flag. */
   ANY_RETAINED = RETAINED
-               | CONDITIONALLY_RETAINED
+               | CONDITIONALLY_RETAINED,
+
+  /** Any returned flag. */
+  ANY_RETURNED = RETURNED
+               | CONDITIONALLY_RETURNED
 }
 export namespace LocalFlags {
   export function join(left: LocalFlags, right: LocalFlags): LocalFlags {
@@ -565,6 +582,7 @@ export class Flow {
       if (flags & LocalFlags.RETAINED) this.setLocalFlag(i, LocalFlags.CONDITIONALLY_RETAINED);
       if (flags & LocalFlags.READFROM) this.setLocalFlag(i, LocalFlags.CONDITIONALLY_READFROM);
       if (flags & LocalFlags.WRITTENTO) this.setLocalFlag(i, LocalFlags.CONDITIONALLY_WRITTENTO);
+      if (flags & LocalFlags.RETURNED) this.setLocalFlag(i, LocalFlags.CONDITIONALLY_RETURNED);
     }
   }