Method builder

tensorflow/compiler/xla/client/xla_builder.h:69–72

Precondition: !IsUninitialized(). It's very common to do foo.builder()->bar(). Without this precondition, if foo.builder() is null, the call to bar will segfault at some point possibly deep in the callstack when we finally dereference `this`. The precondition lets us avoid this tricky-to-debug problem.

  // deep in the callstack when we finally dereference `this`.  The precondition
  // lets us avoid this tricky-to-debug problem.
  XlaBuilder* builder() const {
    CHECK(builder_ != nullptr);
    return builder_;
  }

  // Returns true if the XlaOp represents valid, non-erroneous value.
  bool valid() const { return handle_ >= 0; }