[llvm-dev] Success: Bring-up of LLVM/clang-built Linux ARM(32-bit) kernel for Android - Nexus 5

[Raghavan Santhanam via llvm-dev]

> To be fair, the GCC version which comes with the android ndk has not been
updated for four years, while the clang version is kept up-to-date. It
would be interesting to compare clang and GCC latest releases instead...
that's where the future lies :p

Looks like you didn't read the whole article. Well, for more complete
comparison between GCC and LLVM/clang, I have used four different LLVM/clang
versions(old to to the new), from within the Google's Android NDK and from
outside of the NDK i.e., from other sources, in my project as under :

   1.

*NDK r13b LLVM/clang : Android clang version 3.8.256229  (based on LLVM
   3.8.256229) *
   2.

*Qualcomm Snapdragon LLVM/clang for Android : Snapdragon LLVM ARM Compiler
   4.0.2 for Android NDK (based on llvm.org <http://llvm.org/> 4.0+) - clang
   version 4.0.2 for Android NDK *
   3.

*NDK r17 LLVM/clang : Android (4691093 based on r316199) clang version
   6.0.2 (https://android.googlesource.com/toolchain/clang
   <https://android.googlesource.com/toolchain/clang>183abd29fc496f55536e7d904e0abae47888fc7f)
   (https://android.googlesource.com/toolchain/llvm
   <https://android.googlesource.com/toolchain/llvm>
34361f192e41ed6e4e8f9aca80a4ea7e9856f327)
   (based on LLVM 6.0.2svn) *
   4. *Main LLVM/clang : Flash clang version 7.0.332826
   (https://git.llvm.org/git/clang
   <https://git.llvm.org/git/clang> 4029c7ddda99ecbfa144f0afec44a192c442b6e5)
   (https://git.llvm.org/git/llvm
   <https://git.llvm.org/git/llvm> 1181c40e0e24e0cca32e2609686db1f14151fc1a)
   (based on LLVM 7.0.332826)*

And I saw improved battery usage in all these cases as published over there
in my article. So, read the entire article before making assumptions... :p


On Thu, Jun 14, 2018 at 3:16 PM, Jean-Michaël Celerier <
jeanmichael.celerier at gmail.com> wrote:

> > The main advantage of the clang-built Android ARM(32-bit) hammerhead
> kernel for my Nexus 5 has been the better battery usage when compared to
> that of gcc-built kernel, with the same kernel config and hardware(my Nexus
> 5 Android Smartphone). Details of the same can be found below.
>
> To be fair, the GCC version which comes with the android ndk has not been
> updated for four years, while the clang version is kept up-to-date. It
> would be interesting to compare clang and GCC latest releases instead...
> that's where the future lies :p
>
> -------
> Jean-Michaël Celerier
> http://www.jcelerier.name
>
>
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