Despite the transformative potential of Large Language Models (LLMs) in hardware design, a comprehensive evaluation of their capabilities in design verification remains underexplored. Current efforts predominantly focus on RTL generation and basic debugging, overlooking the critical domain of functional verification, which is the primary bottleneck in modern design methodologies due to the rapid escalation of hardware complexity. We present FIXME, the first end-to-end, multi-model, and open-source evaluation framework for assessing LLM performance in hardware functional verification (FV) to address this crucial gap. FIXME introduces a structured three-level difficulty hierarchy spanning six verification sub-domains and 180 diverse tasks, enabling in-depth analysis across the design lifecycle. Leveraging a collaborative AI-human approach, we construct a high-quality dataset using 100% silicon-proven designs, ensuring comprehensive coverage of real-world challenges. Furthermore, we enhance the functional coverage by 45.57% through expert-guided optimization. By rigorously evaluating state-of-the-art LLMs such as GPT-4, Claude3, and LlaMA3, we identify key areas for improvement and outline promising research directions to unlock the full potential of LLM-driven automation in hardware design verification. The benchmark is available at https://github.com/ChatDesignVerification/FIXME.

The growing complexity of modern hardware designs has rendered traditional functional verification increasingly time-consuming, with verification costs now dominating the design cycle. While large language models (LLMs) show promise in automating testbench generation, existing approaches struggle with real-world scalability, suffering from poor comprehension of long specifications and complex designs. To address these challenges, we propose ChatTest, a novel, end-to-end, multi-agent LLM framework for coverage-aware, agile hardware verification. Our key innovation lies in a function-mapped, divide-and-conquer architecture that integrates a Verification Description Language (VDL)—a structured, LLM-friendly DSL for precise specification encoding—with Constraint-Aware Segmental Adaptation (CASA) to enable coherent processing of long, heterogeneous design documents. By leveraging retrieval-augmented generation and supervised fine-tuning using multi-hierarchical specification-code alignment, ChatTest ensures accurate translation of functional points into targeted test stimuli. Furthermore, we introduce a coverage-driven feedback loop for automated test augmentation. Evaluated on a new benchmark of 20 complex RTL designs (up to 31K tokens of specification and 4K line-of-code), ChatTest achieves 1.46× higher toggle coverage and 2.28× higher line coverage than SOTA, with a 24.23% improvement in functional coverage, demonstrating its effectiveness in accelerating verification convergence.