Godson-2 Link Time Optimizer Implementation And Analysis

Link time optimization is a technique which optimizes the whole program aftercompilation. It overcomes the limitations of traditional compiler by enlarging the optimizingscope from a single function or a module to the whole program, and fully utilizes theinformation only available at link time to exploit more optimizing opportunities. Guided by thelink time optimizer ALTO developed by Arizona University for Alpha, we implement theGLTO (Godson Link Time Optimizer) with consideration of the features of themicroarchitecture and instruction set of Godson-2 Processor. GLTO can achieve a 9.4%performance improvement on the SPEC2000 integer benchmark with reference input onGodson-2C platform and 9.2% on Godson-2E platform on average. This paper explores theeffect and the cause of effect of several major optimizing methods, proposes someimprovements in the architecture design, presents several optimizations according to GodsonISA, proposes specific optimization techniques and analyzes the combination of optimizationoptions on Godson-2E platform, finally presents the differences between GLTO and ALTO.