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LLVM description (for example, here says it is a framework for lifelong program analysis and transformation.

What does lifelong mean in this context?

sharptooth
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    I believe it refers to LLVM's ability to analyse and transform a program throughout its entire lifetime. Once the program is in its bytecode form, it can be analysed and transformed starting at its initial compilation all the way to the moment when it is being executed (see link time and install time optimizations as well as the LLVM JIT). Note that this is just a guess but it does seem to fit. – Ze Blob Oct 17 '11 at 14:20

2 Answers2

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"Such lifelong code optimization techniques encompass interprocedural optimizations performed at link-time (to preserve the benefits of separate compilation), machine-dependent optimizations at install time on each system, dynamic optimization at runtime, and profile-guided optimization between runs ('idle time') using profile information collected from the end-user."

This was extracted from the second paragraph of this paper: http://llvm.org/pubs/2004-01-30-CGO-LLVM.pdf

JohnTortugo
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Lifelong in the phrase means the lifetime of the program. So to maximize the efficiency of a program it be analyzed at link-time, run-time, and in between runs as well.

In the paper (on the 5th page) they list out the requirements for lifelong program analysis and transformation:

  1. persistent program information
  2. offline code generation
  3. user-based profiling and optimization
  4. transparent runtime model
  5. uniform, whole program compilation.
A. K.
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