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]
 | |
| Developer(s) | GNU Project |
|---|---|
| Initial release | January 19, 2001[1] |
| Stable release | 2.2.3[2] 
/ 8 February 2024 |
| 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 |
Advantages over other libraries
editThe 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.
Disadvantages
editIt 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 [1].
Instruction set
editGNU lightning's instruction set is based loosely on existing RISC architectures.
Types
editWhen 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 |
Projects that use GNU lightning
editGNU Smalltalk,[8] GNU Guile,[9] and CLISP[10] 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.[11] 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.[12]
Notes
editReferences
edit- ^ "ChangeLog". GNU Project. Retrieved 2009-02-22.
- ^ Paulo César Pereira de Andrade (8 February 2024). "GNU lightning 2.2.3 released!". Retrieved 8 March 2024.
- ^ "README-hacking".
- ^ "lightning-1.1.1.tar.gz".
- ^ "GNU lightning". Retrieved 2020-01-15.
- ^ "GNU lightning 2.1.3 released!". 2019-09-18.
- ^ "Using and porting GNU lightning". Retrieved 2009-02-22.
- ^ "GNU Smalltalk project page". Retrieved 2014-05-17.
- ^ "Just-In-Time Native Code". Archived from the original on 2020-05-13. Retrieved 2019-03-11.
- ^ "Implementation notes for GNU CLISP". Retrieved 2009-02-23.
- ^ "GNU lightning user manual, acknowledgements". Retrieved 2014-05-17.
- ^ "lightening run-time code generation -- wingolog". Retrieved 2021-12-10.
External links
edit
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