In this article we want to address the issue of GNU lightning, which has gained unprecedented relevance in recent years. GNU lightning is a topic that has captured the attention of experts in various fields and has generated an intense debate worldwide. There are many aspects that can be explored in this regard, from its impact on society to its implications in the economic sphere. Along these lines, we intend to delve into the various perspectives that exist on GNU lightning, as well as the possible future scenarios that could arise from its evolution. Without a doubt, this is a topic of great complexity and scope, so it is essential to analyze it from multiple angles to fully understand its importance and significance today.
| GNU lightning | |
|---|---|
| Developer | GNU Project |
| Initial release | January 19, 2001[1] |
| Stable release | 2.2.3[2] |
| Repository | |
| Operating system | Cross-platform |
| Platform | GNU |
| Type | Just-in-time compilation |
| License | 2007: LGPL-3.0-or-later[a] 2002: LGPL-2.1-or-later[b] |
| Website | Official website |
GNU lightning is a free-software library for generating assembly language code at run-time. Version 2.1.3, released in September 2019, supports backends for SPARC (32-bit), x86 (32- and 64-bit), MIPS, ARM (32- and 64-bit), ia64, HPPA, PowerPC (32-bit), Alpha, S390 and RISC-V (64-bit).[5][6]
The features GNU lightning provides make it useful for Just-in-Time Compilation. In comparison to libraries such as LLVM or libJIT, GNU lightning provides only a low-level interface for assembling from a standardized RISC assembly language—loosely based on the SPARC and MIPS architectures[7]—into the target architecture's machine language.
It does not provide register allocation, data-flow or control-flow analysis, or optimization.[citation needed] Starting from 2.x, it generates code via intermediate graph, rather than one by one from each of its standardized instructions. This change allows inter-instruction optimization such as register allocation and dead code elimination.[8]
GNU lightning's instruction set is based loosely on existing RISC architectures.
When required instructions handle data with these 9 types:
| Type | C equivalent |
|---|---|
| c | signed char |
| uc | unsigned char |
| s | short |
| us | unsigned short |
| i | int |
| ui | unsigned int |
| l | long |
| f | float |
| d | double |
GNU Smalltalk,[9] GNU Guile,[10] and CLISP[11] make use of GNU lightning for just-in-time compilation. GNU lightning was first developed as a tool to be used in GNU Smalltalk's dynamic translator from bytecodes to native code.[12] GNU Guile 2.9.2 and later stop using GNU lightning 2.x instead their own fork based on GNU lightning 1.4 for native code generation, because GNU lightning 2.x devotes more complexity to inter-instruction optimization.[13]