[libcxx-commits] [libcxx] 0eb1fc8 - [libcxx] Set `_LIBCPP_HAS_CLOCK_GETTIME` for GPU targets (#99243)

[via libcxx-commits]

Author: Joseph Huber
Date: 2024-08-14T12:19:08-05:00
New Revision: 0eb1fc88680e2df430a5cb68be5e6a671b43c82d

URL: https://github.com/llvm/llvm-project/commit/0eb1fc88680e2df430a5cb68be5e6a671b43c82d
DIFF: https://github.com/llvm/llvm-project/commit/0eb1fc88680e2df430a5cb68be5e6a671b43c82d.diff

LOG: [libcxx] Set `_LIBCPP_HAS_CLOCK_GETTIME` for GPU targets (#99243)

Summary:
I am attempting to get the GPU to build and support libc++. One issue
I've encountered is that it will look for `timeval` unless this macro is
set. We can support `CLOCK_MONOTONIC` on the GPU fairly easily as we
have access to a fixed-frequency clock via `__builtin_readsteadycounter`
intrinsics with a known frequency. This also requires `CLOCK_REALTIME`
which we can't support, but provide anyway from the GPU `libc` to make
this happy. It will return an error so at least that will be obvious.

I may need a more consistent configuration for this in the future, maybe
I should put a common macro in a different common header that's just
`__GPU__`? I don't know where I would put such a thing however.

Added: 
    

Modified: 
    libcxx/src/chrono.cpp
    libcxx/src/filesystem/filesystem_clock.cpp

Removed: 
    


################################################################################
diff  --git a/libcxx/src/chrono.cpp b/libcxx/src/chrono.cpp
index 83e8a64504ae0b..986360d0368a09 100644
--- a/libcxx/src/chrono.cpp
+++ b/libcxx/src/chrono.cpp
@@ -31,9 +31,10 @@
 #  include <sys/time.h> // for gettimeofday and timeval
 #endif
 
-// OpenBSD does not have a fully conformant suite of POSIX timers, but
+// OpenBSD and GPU do not have a fully conformant suite of POSIX timers, but
 // it does have clock_gettime and CLOCK_MONOTONIC which is all we need.
-#if defined(__APPLE__) || defined(__gnu_hurd__) || defined(__OpenBSD__) || (defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0)
+#if defined(__APPLE__) || defined(__gnu_hurd__) || defined(__OpenBSD__) || defined(__AMDGPU__) ||                      \
+    defined(__NVPTX__) || (defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0)
 #  define _LIBCPP_HAS_CLOCK_GETTIME
 #endif
 

diff  --git a/libcxx/src/filesystem/filesystem_clock.cpp b/libcxx/src/filesystem/filesystem_clock.cpp
index e13b2853e367c1..473a54a00f013a 100644
--- a/libcxx/src/filesystem/filesystem_clock.cpp
+++ b/libcxx/src/filesystem/filesystem_clock.cpp
@@ -29,7 +29,8 @@
 #  include <sys/time.h> // for gettimeofday and timeval
 #endif
 
-#if defined(__APPLE__) || defined(__gnu_hurd__) || (defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0)
+#if defined(__APPLE__) || defined(__gnu_hurd__) || defined(__AMDGPU__) || defined(__NVPTX__) ||                        \
+    (defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0)
 #  define _LIBCPP_HAS_CLOCK_GETTIME
 #endif