[Openmp-commits] [PATCH] D108349: [openmp][devicertl] Freestanding nvptx via stub printf

[Jon Chesterfield via Phabricator via Openmp-commits]

JonChesterfield created this revision.
JonChesterfield added reviewers: jdoerfert, ABataev, grokos, tianshilei1992, ye-luo.
Herald added subscribers: guansong, yaxunl, mgorny.
JonChesterfield requested review of this revision.
Herald added subscribers: openmp-commits, sstefan1.
Herald added a project: OpenMP.

Compiled nvptx devicertl as freestanding, breaking the
dependency on host glibc and gcc-multilibs. Thus build it by default.

Comes at the cost of #defining out printf. Tried mapping it onto
__builtin_printf but that gets transformed back to printf instead
of hitting the cuda/openmp lowering transform.

Printf could be preserved by one of:

- dropping all the standard headers and ffreestanding
- providing a header only printf implementation
- changing the compiler handling of printf


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D108349

Files:
  openmp/libomptarget/deviceRTLs/nvptx/CMakeLists.txt
  openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.cu
  openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.h


Index: openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.h
===================================================================
--- openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.h
+++ openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.h
@@ -12,12 +12,15 @@
 #ifndef _TARGET_IMPL_H_
 #define _TARGET_IMPL_H_
 
-#include <inttypes.h>
-#include <stdio.h>
-#include <stdlib.h>
-
 #include "nvptx_interface.h"
 
+#include <stddef.h>
+#include <stdint.h>
+
+// subset of inttypes.h
+#define PRId64 "ld"
+#define PRIu64 "lu"
+
 #define INLINE inline __attribute__((always_inline))
 #define NOINLINE __attribute__((noinline))
 #define ALIGN(N) __attribute__((aligned(N)))
@@ -77,4 +80,6 @@
   __kmpc_impl_all_lanes = ~(__kmpc_impl_lanemask_t)0
 };
 
+#define printf(...)
+
 #endif
Index: openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.cu
===================================================================
--- openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.cu
+++ openmp/libomptarget/deviceRTLs/nvptx/src/target_impl.cu
@@ -181,6 +181,11 @@
   return __kmpc_atomic_add(lock, 0u);
 }
 
+extern "C" {
+void *malloc(size_t);
+void free(void *);
+}
+
 EXTERN void *__kmpc_impl_malloc(size_t x) { return malloc(x); }
 EXTERN void __kmpc_impl_free(void *x) { free(x); }
 
Index: openmp/libomptarget/deviceRTLs/nvptx/CMakeLists.txt
===================================================================
--- openmp/libomptarget/deviceRTLs/nvptx/CMakeLists.txt
+++ openmp/libomptarget/deviceRTLs/nvptx/CMakeLists.txt
@@ -11,7 +11,7 @@
 ##===----------------------------------------------------------------------===##
 
 # By default we will not build NVPTX deviceRTL on a CUDA free system
-set(LIBOMPTARGET_BUILD_NVPTX_BCLIB FALSE CACHE BOOL
+set(LIBOMPTARGET_BUILD_NVPTX_BCLIB TRUE CACHE BOOL
   "Whether build NVPTX deviceRTL on CUDA free system.")
 
 if (NOT (LIBOMPTARGET_DEP_CUDA_FOUND OR LIBOMPTARGET_BUILD_NVPTX_BCLIB))
@@ -154,6 +154,7 @@
 # Set flags for LLVM Bitcode compilation.
 set(bc_flags -S -x c++ -O1 -std=c++14
              -mllvm -openmp-opt-disable
+             -ffreestanding
              -target nvptx64
              -Xclang -emit-llvm-bc
              -Xclang -aux-triple -Xclang ${aux_triple}


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