From Patterns to Parsers: Automatic Generation of Efficient Hardware Parsers for FPGAs
This work presents an open-source tool for automatically generating efficient hardware parsers from high-level specifications. It uses a parsing intermediate representation (PIR) that decouples application-specific frontends from a common register-transfer level (RTL) generation backend. The backend produces optimized, human-readable SystemVerilog, handling FSM generation, byte-alignment, and multi-cycle field straddling for arbitrary datapath widths. The tool also extends pattern matching beyond simple equality checks by introducing custom symbolic tokens to support operations that existing parser generators cannot express, such as range validation, negation, and comparisons against external ports. We demonstrate two end-to-end flows using a P4 frontend for Ethernet protocol parsing and a Snort frontend for network intrusion detection, both using the same unmodified backend. The generated Ethernet parsers achieve up to 226% higher operating frequency and up to 97% fewer FPGA logic resources than prior work. A controlled synthetic study further shows that the tool's hierarchical pattern decomposition yields up to 8x resource utilization reduction over monolithic designs. Our open-source framework enables designers to rapidly implement high-performance, resource-efficient, vendor-agnostic hardware parsers for diverse applications.