[csa] Add assertions to CSA

src/code-stub-assembler.h

Index: src/code-stub-assembler.h
diff --git a/src/code-stub-assembler.h b/src/code-stub-assembler.h
index de81105b1e4bee1995cf6082e36fb5f8bd5c91da..5bfe8be554d2226488ece11f0a886d4bc2d69473 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -114,6 +114,8 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
     return value;
   }
 
+  Node* IsParameterMode(Node* value, ParameterMode mode);
+
 #define PARAMETER_BINOP(OpName, IntPtrOpName, SmiOpName) \
   Node* OpName(Node* a, Node* b, ParameterMode mode) {   \
     if (mode == SMI_PARAMETERS) {                        \
@@ -761,6 +763,8 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   Node* IsJSArrayInstanceType(Node* instance_type);
   Node* IsJSArray(Node* object);
   Node* IsJSArrayMap(Node* object);
+  Node* IsFixedArray(Node* object);
+  Node* IsFixedArrayWithKind(Node* object, ElementsKind kind);
   Node* IsNativeContext(Node* object);
   Node* IsWeakCell(Node* object);
   Node* IsFixedDoubleArray(Node* object);
@@ -803,16 +807,6 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
   Node* StringAdd(Node* context, Node* first, Node* second,
                   AllocationFlags flags = kNone);
 
-  // Unpack the external string, returning a pointer that (offset-wise) looks
-  // like a sequential string.
-  // Note that this pointer is not tagged and does not point to a real
-  // sequential string instance, and may only be used to access the string
-  // data. The pointer is GC-safe as long as a reference to the container
-  // ExternalString is live.
-  // |string| must be an external string. Bailout for short external strings.
-  Node* TryDerefExternalString(Node* const string, Node* const instance_type,
-                               Label* if_bailout);
-
   // Check if |var_string| has an indirect (thin or flat cons) string type,
   // and unpack it if so.
   void MaybeDerefIndirectString(Variable* var_string, Node* instance_type,
@@ -1553,7 +1547,7 @@ class ToDirectStringAssembler : public CodeStubAssembler {
   Variable var_is_external_;
 };
 
-#ifdef DEBUG
+#if defined(DEBUG) || defined(ENABLE_SLOW_DCHECKS)
 #define CSA_ASSERT(csa, x) \
   (csa)->Assert([&] { return (x); }, #x, __FILE__, __LINE__)
 #define CSA_ASSERT_JS_ARGC_OP(csa, Op, op, expected)             \