[wasm] Fix interpreter multi-value stack height issue

Block inputs are removed from the stack. Set expected stack height
accordingly.

R=ahaas@chromium.org

Bug: v8:9867
Change-Id: I7e3fd2985c0e77e83d5551cac613788f3cf0a370
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1872404
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64465}

src/wasm/wasm-debug.cc

@@ -221,11 +221,14 @@ class InterpreterHandle {
     }
 
     // Copy back the return value.
-    DCHECK_GE(kV8MaxWasmFunctionReturns, sig->return_count());
-    // TODO(wasm): Handle multi-value returns.
-    DCHECK_EQ(1, kV8MaxWasmFunctionReturns);
-    if (sig->return_count()) {
-      return_values[0] = thread->GetReturnValue(0);
+#ifdef DEBUG
+    const int max_count = WasmFeaturesFromIsolate(isolate_).mv
+                              ? kV8MaxWasmFunctionMultiReturns
+                              : kV8MaxWasmFunctionReturns;
+#endif
+    DCHECK_GE(max_count, sig->return_count());
+    for (unsigned i = 0; i < sig->return_count(); ++i) {
+      return_values[i] = thread->GetReturnValue(i);
     }
 
     FinishActivation(frame_pointer, activation_id);

src/wasm/wasm-interpreter.cc

@@ -826,7 +826,7 @@ class SideTable : public ZoneObject {
           TRACE("control @%u: %s, arity %d->%d\n", i.pc_offset(),
                 is_loop ? "Loop" : "Block", imm.in_arity(), imm.out_arity());
           CLabel* label =
-              CLabel::New(&control_transfer_zone, stack_height,
+              CLabel::New(&control_transfer_zone, stack_height - imm.in_arity(),
                           is_loop ? imm.in_arity() : imm.out_arity());
           control_stack.emplace_back(i.pc(), label, imm.out_arity());
           copy_unreachable();
@@ -841,8 +841,9 @@ class SideTable : public ZoneObject {
           }
           TRACE("control @%u: If, arity %d->%d\n", i.pc_offset(),
                 imm.in_arity(), imm.out_arity());
-          CLabel* end_label = CLabel::New(&control_transfer_zone, stack_height,
-                                          imm.out_arity());
+          CLabel* end_label =
+              CLabel::New(&control_transfer_zone, stack_height - imm.in_arity(),
+                          imm.out_arity());
           CLabel* else_label =
               CLabel::New(&control_transfer_zone, stack_height, 0);
           control_stack.emplace_back(i.pc(), end_label, else_label,
@@ -861,9 +862,9 @@ class SideTable : public ZoneObject {
           DCHECK_NOT_NULL(c->else_label);
           c->else_label->Bind(i.pc() + 1);
           c->else_label->Finish(&map_, code->orig_start);
+          stack_height = c->else_label->target_stack_height;
           c->else_label = nullptr;
           DCHECK_GE(stack_height, c->end_label->target_stack_height);
-          stack_height = c->end_label->target_stack_height;
           break;
         }
         case kExprTry: {

test/mjsunit/wasm/multi-value-interpreter.js

+// Copyright 2017 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --experimental-wasm-mv --wasm-interpret-all
+
+load("test/mjsunit/wasm/multi-value.js");