SPARK is a C-to-VHDL high-level synthesis framework that employs a set of innovative compiler, parallelizing compiler, and synthesis transformations to improve the quality of high-level synthesis results. The compiler transformations have been re-instrumented for synthesis by incorporating ideas of mutual exclusivity of operations, resource sharing and hardware cost models. The SPARK parallelizing high-level synthesis methodology is particularly targeted to multimedia and image processing applications along with control-intensive microprocessor functional blocks. 

SPARK takes a behavioral description in ANSI-C as input -- currently with the restrictions of no pointers, no function recursion, and no irregular control-flow jumps. SPARK also takes additional information as input, such as a hardware resource library, resource and timing constraints and user directives for the various heuristics and transformations.

SPARK is still in research stage with inefficient coding but it is good example of high level synthesis tool may look like in future. Performance is still issue but atleast there is basic framework to start with.

Link - SPARK: A Parallelizing Approach to the High-Level Synthesis of Digital Circuits