This refactors getHostCPUName so that for the architectures that get the
host cpu info on linux from /proc/cpuinfo, the /proc/cpuinfo parsing
logic is present in the build, even if it wasn't built on a linux system
for that architecture.
Since the code is present in the build, we can then test that code also
on other systems, i.e. we don't need to have buildbots setup for all
architectures on linux to be able to test this. Instead, developers will
test this as part of the regression test run.
As an example, a few unit tests are added to test getHostCPUName for ARM
running linux. A unit test is preferred over a lit-based test, since the
expectation is that in the future, the functionality here will grow over
what can be tested with "llc -mcpu=native".
This is a preparation step to enable implementing the range of
improvements discussed on PR30516, such as adding AArch64 support,
support for big.LITTLE systems, reducing code duplication.
Differential Revision: https://reviews.llvm.org/D31236
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299060 91177308-0d34-0410-b5e6-96231b3b80d8
If LLVM was configured with an x86_64-apple-macosx host triple, this
test would fail, as the API works but the triple isn't in the whitelist.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293990 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
For now I have only added support for x86_64 Linux, but other systems
can be added incrementally.
This is to be used for setting the default parallelism for ThinLTO
backends (instead of thread::hardware_concurrency which includes
hyperthreading and is too aggressive). I'll send this as a follow-on
patch, and it will fall back to hardware_concurrency when the new
getHostNumPhysicalCores returns -1 (when not supported for a given
host system).
I also added an interface to MemoryBuffer to force reading a file
as a stream - this is required for /proc/cpuinfo which is a special
file that looks like a normal file but appears to have 0 size.
The existing readers of this file in Host.cpp are reading the first
1024 or so bytes from it, because the necessary info is near the top.
But for the new functionality we need to be able to read the entire
file. I can go back and change the other readers to use the new
getFileAsStream as a follow-on patch since it seems much more robust.
Added a unittest.
Reviewers: mehdi_amini
Subscribers: beanz, mgorny, llvm-commits, modocache
Differential Revision: https://reviews.llvm.org/D25564
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284138 91177308-0d34-0410-b5e6-96231b3b80d8
