[Openmp-commits] [openmp] [Libomptarget] Make the references to 'malloc' and 'free' weak. (PR #69356)

[Joseph Huber via Openmp-commits]

https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/69356

Summary:
We use `malloc` internally in the DeviceRTL to handle data
globalization. If this is undefined it will map to the Nvidia
implementation of `malloc` for NVPTX and return `nullptr` for AMDGPU.
This is somewhat problematic, because when using this as a shared
library it causes us to always extract the GPU libc implementation,
which uses RPC and thus requires an RPC server. Making this `weak`
allows us to implement this internally without worrying about binding to
the GPU `libc` implementation.


>From 9c44ea8ab569e5995261ea77b62ae1fc6d94370a Mon Sep 17 00:00:00 2001
From: Joseph Huber <jhuber6 at vols.utk.edu>
Date: Tue, 17 Oct 2023 11:45:19 -0500
Subject: [PATCH] [Libomptarget] Make the references to 'malloc' and 'free'
 weak.

Summary:
We use `malloc` internally in the DeviceRTL to handle data
globalization. If this is undefined it will map to the Nvidia
implementation of `malloc` for NVPTX and return `nullptr` for AMDGPU.
This is somewhat problematic, because when using this as a shared
library it causes us to always extract the GPU libc implementation,
which uses RPC and thus requires an RPC server. Making this `weak`
allows us to implement this internally without worrying about binding to
the GPU `libc` implementation.
---
 openmp/libomptarget/DeviceRTL/src/State.cpp | 4 ++--
 openmp/libomptarget/DeviceRTL/src/exports   | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/openmp/libomptarget/DeviceRTL/src/State.cpp b/openmp/libomptarget/DeviceRTL/src/State.cpp
index 721137cb95d658b..422747a94e7943a 100644
--- a/openmp/libomptarget/DeviceRTL/src/State.cpp
+++ b/openmp/libomptarget/DeviceRTL/src/State.cpp
@@ -46,8 +46,8 @@ namespace {
 ///{
 
 extern "C" {
-__attribute__((leaf)) void *malloc(uint64_t Size);
-__attribute__((leaf)) void free(void *Ptr);
+[[gnu::weak, gnu::leaf]] void *malloc(uint64_t Size);
+[[gnu::weak, gnu::leaf]] void free(void *Ptr);
 }
 
 ///}
diff --git a/openmp/libomptarget/DeviceRTL/src/exports b/openmp/libomptarget/DeviceRTL/src/exports
index fbcda3ce8f555ca..288ddf90b4a9f2d 100644
--- a/openmp/libomptarget/DeviceRTL/src/exports
+++ b/openmp/libomptarget/DeviceRTL/src/exports
@@ -11,6 +11,8 @@ _ZN4ompx*
 
 IsSPMDMode
 
+malloc
+free
 memcmp
 printf
 __assert_fail