Merge pull request #3441 from kinke/fix_captured_nonpassed

Fix ICE for *captured* parameters *not* passed on the LLVM level

dmd/semantic3.d

@@ -411,29 +411,6 @@ private extern(C++) final class Semantic3Visitor : Visitor
                 }
             }
 
-version (IN_LLVM)
-{
-            // Make sure semantic analysis has been run on argument types. This is
-            // e.g. needed for TypeTuple!(int, int) to be picked up as two int
-            // parameters by the Parameter functions.
-            for (size_t i = 0; i < f.parameterList.length; i++)
-            {
-                Parameter arg = f.parameterList[i];
-                Type nw = arg.type.typeSemantic(Loc.initial, sc);
-                if (arg.type != nw)
-                {
-                    arg.type = nw;
-                    // Examine this index again.
-                    // This is important if it turned into a tuple.
-                    // In particular, the empty tuple should be handled or the
-                    // next parameter will be skipped.
-                    // LDC_FIXME: Maybe we only need to do this for tuples,
-                    //            and can add tuple.length after decrement?
-                    i--;
-                }
-            }
-}
-
             /* Declare all the function parameters as variables
              * and install them in parameters[]
              */

gen/abi-aarch64.cpp

@@ -83,10 +83,12 @@ public:
     }
 
     // remove 0-sized args (static arrays with 0 elements) and, for Darwin,
-    // empty structs too
+    // empty POD structs too
     size_t i = 0;
     while (i < fty.args.size()) {
-      auto tb = fty.args[i]->type->toBasetype();
+      auto arg = fty.args[i];
+      if (!arg->byref) {
+        auto tb = arg->type->toBasetype();
 
         if (tb->size() == 0) {
           fty.args.erase(fty.args.begin() + i);
@@ -96,12 +98,13 @@ public:
         // https://developer.apple.com/library/archive/documentation/Xcode/Conceptual/iPhoneOSABIReference/Articles/ARM64FunctionCallingConventions.html#//apple_ref/doc/uid/TP40013702-SW1
         if (isDarwin) {
           if (auto ts = tb->isTypeStruct()) {
-          if (ts->sym->fields.empty()) {
+            if (ts->sym->fields.empty() && ts->sym->isPOD()) {
               fty.args.erase(fty.args.begin() + i);
               continue;
             }
           }
         }
+      }
 
       ++i;
     }

gen/functions.cpp

@@ -815,22 +815,24 @@ void defineParameters(IrFuncTy &irFty, VarDeclarations &parameters) {
   size_t llArgIdx = 0;
 
   for (VarDeclaration *vd : parameters) {
+    Type *paramType = vd->type;
     IrParameter *irparam = getIrParameter(vd);
 
-    // vd->type (parameter) and irparam->arg->type (argument) don't always
-    // match.
-    // E.g., for a lazy parameter of type T, vd->type is T (with lazy storage
-    // class) while irparam->arg->type is the delegate type.
-    Type *const paramType = (irparam ? irparam->arg->type : vd->type);
-
     if (!irparam) {
       // This is a parameter that is not passed on the LLVM level.
       // Create the param here and set it to a "dummy" alloca that
       // we do not store to here.
       irparam = getIrParameter(vd, true);
       irparam->value = DtoAlloca(vd, vd->ident->toChars());
+    } else if (!irparam->value) {
+      // Captured parameter not passed on the LLVM level.
+      assert(irparam->nestedIndex >= 0);
+      irparam->value = DtoAlloca(vd, vd->ident->toChars());
     } else {
-      assert(irparam->value);
+      // vd->type (parameter) and irparam->arg->type (argument) don't always
+      // match. E.g., for a lazy parameter of type T, vd->type is T (with lazy
+      // storage class) while irparam->arg->type is the delegate type.
+      paramType = irparam->arg->type;
 
       if (irparam->arg->byref) {
         // The argument is an appropriate lvalue passed by reference.

gen/nested.cpp

@@ -392,14 +392,17 @@ static void DtoCreateNestedContextType(FuncDeclaration *fd) {
       builder.alignCurrentOffset(alignment);
     }
 
-    IrLocal &irLocal = *getIrLocal(vd, true);
+    const bool isParam = vd->isParameter();
+
+    IrLocal &irLocal =
+        *(isParam ? getIrParameter(vd, true) : getIrLocal(vd, true));
     irLocal.nestedIndex = builder.currentFieldIndex();
     irLocal.nestedDepth = depth;
 
     LLType *t = nullptr;
     if (vd->isRef() || vd->isOut()) {
       t = DtoType(vd->type->pointerTo());
-    } else if (vd->isParameter() && (vd->storage_class & STClazy)) {
+    } else if (isParam && (vd->storage_class & STClazy)) {
       // the type is a delegate (LL struct)
       Type *dt = TypeFunction::create(nullptr, vd->type, VARARGnone, LINKd);
       dt = createTypeDelegate(dt);

tests/compilable/captured_nonpassed_params.d

@@ -0,0 +1,35 @@
+// Some ABIs don't pass empty static arrays or empty PODs as arguments.
+// This can get hairy, e.g., if such a parameter is captured.
+
+// RUN: %ldc -c -g %s
+
+struct EmptyPOD {}
+
+EmptyPOD emptyPOD(EmptyPOD e)
+{
+    EmptyPOD nested() { return e; }
+    nested();
+    return e;
+}
+
+int[0] emptySArray(int[0] a)
+{
+    int[0] nested() { return a; }
+    nested();
+    return a;
+}
+
+void tuple()
+{
+    auto test(T...)(T params)
+    {
+        auto nested() { return params[0]; }
+        nested();
+        return params[0];
+    }
+
+    test(EmptyPOD());
+
+    int[0] a;
+    test(a);
+}