5 ms·

Introduction to LLVM [video]

271 points by matt_d 9y ago

t-ob 9y ago
I attended this talk, and it was one of the highlights of the conference for me. Mike is a great speaker and I found myself inspired to dive deeper into LLVM internals afterwards.
marksomnian 9y ago
[video]
matt_d 9y ago
Slides and code examples: http://www.mshah.io/fosdem18.html http://www.mshah.io/fosdem18.html
josteink 9y ago
Youtube mirror, for those who'd like to add it to their "Watch later"-list: https://www.youtube.com/watch?v=VKIv_Bkp4pk https://www.youtube.com/watch?v=VKIv_Bkp4pk
- brownmenace 9y ago
  You're my hero
- jxramos 9y ago
  Was just about to do the same, regrettable about the audio quality.
- collinmanderson 9y ago
  Or for those who want to easily watch on 2x speed.
  - jakeogh 9y ago
    mpv does a nice job with that '[' and ']' select any arb speed and '.' steps frame by frame (with sound).
perbu 9y ago
Mike says in his talk that LLVM started out with the goal of having an intermediate representation to run optimizations on. Hasn't this always been the case with compilers in recent times? I seem to recall similar things being said about the GNU Compiler Collection at a presentation many years ago. If this is true, what is (was) the appeal of the LLVM project at the time of the project inception?
- Baltoli 9y ago
  At its inception the appeal was the "multi-stage optimisation system" and the virtual instruction set design (from https://llvm.org/pubs/2002-12-LattnerMSThesis.html https://llvm.org/pubs/2002-12-LattnerMSThesis.html)
  - mrami 9y ago
    At the time, I had a DSL I had written in C++, and I wanted to produce proper compiled binaries. I had started looking at the now defunct TenDRA - I was thinking it would be nice to compile to a "machine-independent binary" which could be converted to machine code on the actual runtime system. But soon after I found LLVM, and it seemed like a no-brainer comparatively. I seem to remember that "machine-independent binaries" was Apple's first use of LLVM: distributing LLVM IR and having it be converted to machine code on the user's computer, back when they were supporting Motorola and Intel chips. And I think consequently that's how LLVM got a lot of its momentum.
- oselhn 9y ago
  As I understand it, difference is more political than technical. GCC is made to prevent people plug in nonfree parts into compiler. So you cannot plug in your dynamic library or use part of GCC as library which is artificial restriction. See this https://gcc.gnu.org/ml/gcc/2014-01/msg00247.html https://gcc.gnu.org/ml/gcc/2014-01/msg00247.html, https://channel9.msdn.com/Events/GoingNative/GoingNative-2012/Clang-Defending-C-from-Murphy-s-Million-Monkeys https://channel9.msdn.com/Events/GoingNative/GoingNative-201...
  - deleted 9y ago
thefourthchime 9y ago
Shame the mic is so hot, it's really hard to listen to.

271 points by matt_d 9y ago

t-ob 9y ago

I attended this talk, and it was one of the highlights of the conference for me. Mike is a great speaker and I found myself inspired to dive deeper into LLVM internals afterwards.

marksomnian 9y ago

[video]

matt_d 9y ago

Slides and code examples: http://www.mshah.io/fosdem18.html http://www.mshah.io/fosdem18.html

josteink 9y ago

Youtube mirror, for those who'd like to add it to their "Watch later"-list: https://www.youtube.com/watch?v=VKIv_Bkp4pk https://www.youtube.com/watch?v=VKIv_Bkp4pk

brownmenace 9y ago
You're my hero
jxramos 9y ago
Was just about to do the same, regrettable about the audio quality.
collinmanderson 9y ago
Or for those who want to easily watch on 2x speed.
- jakeogh 9y ago
  mpv does a nice job with that '[' and ']' select any arb speed and '.' steps frame by frame (with sound).

perbu 9y ago

Mike says in his talk that LLVM started out with the goal of having an intermediate representation to run optimizations on. Hasn't this always been the case with compilers in recent times? I seem to recall similar things being said about the GNU Compiler Collection at a presentation many years ago. If this is true, what is (was) the appeal of the LLVM project at the time of the project inception?

Baltoli 9y ago
At its inception the appeal was the "multi-stage optimisation system" and the virtual instruction set design (from https://llvm.org/pubs/2002-12-LattnerMSThesis.html https://llvm.org/pubs/2002-12-LattnerMSThesis.html)
- mrami 9y ago
  At the time, I had a DSL I had written in C++, and I wanted to produce proper compiled binaries. I had started looking at the now defunct TenDRA - I was thinking it would be nice to compile to a "machine-independent binary" which could be converted to machine code on the actual runtime system. But soon after I found LLVM, and it seemed like a no-brainer comparatively. I seem to remember that "machine-independent binaries" was Apple's first use of LLVM: distributing LLVM IR and having it be converted to machine code on the user's computer, back when they were supporting Motorola and Intel chips. And I think consequently that's how LLVM got a lot of its momentum.
oselhn 9y ago
As I understand it, difference is more political than technical. GCC is made to prevent people plug in nonfree parts into compiler. So you cannot plug in your dynamic library or use part of GCC as library which is artificial restriction. See this https://gcc.gnu.org/ml/gcc/2014-01/msg00247.html https://gcc.gnu.org/ml/gcc/2014-01/msg00247.html, https://channel9.msdn.com/Events/GoingNative/GoingNative-2012/Clang-Defending-C-from-Murphy-s-Million-Monkeys https://channel9.msdn.com/Events/GoingNative/GoingNative-201...
- deleted 9y ago

thefourthchime 9y ago

Shame the mic is so hot, it's really hard to listen to.