[libc-commits] [libc] [libc] Fix building the RPC server with LIBC_NAMESPACE (PR #65642)

[Joseph Huber via libc-commits]

https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/65642:

A recent patch required the implementation to define `LIBC_NAMESPACE`.
For GPU offloading we provide a static library whose internal
implementation relies on the `libc` headers. This is a separate library
that is constructed during the "bootstrap" phase. This patch moves the
definition of the `LIBC_NAMESPACE` CMake variable up so its available
during bootstrapping and adds it to the definition of the RPC server.


>From d2f4ac04afa5d464d15af8ed7c3469f3f096204a Mon Sep 17 00:00:00 2001
From: Joseph Huber <jhuber6 at vols.utk.edu>
Date: Thu, 7 Sep 2023 12:08:12 -0500
Subject: [PATCH] [libc] Fix building the RPC server with LIBC_NAMESPACE

Summary:
A recent patch required the implementation to define `LIBC_NAMESPACE`.
For GPU offloading we provide a static library whose internal
implementation relies on the `libc` headers. This is a separate library
that is constructed during the "bootstrap" phase. This patch moves the
definition of the `LIBC_NAMESPACE` CMake variable up so its available
during bootstrapping and adds it to the definition of the RPC server.
---
 libc/CMakeLists.txt                  | 10 +++++-----
 libc/utils/gpu/server/CMakeLists.txt |  2 ++
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index b2ad91828dce8d3..0665cf0f7a1d900 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -19,6 +19,11 @@ set(LIBC_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR})
 
 set(LIBC_ENABLE_USE_BY_CLANG OFF CACHE BOOL "Whether or not to place libc in a build directory findable by a just built clang")
 
+# Defining a global namespace to enclose all libc functions.
+set(LIBC_NAMESPACE "__llvm_libc_${LLVM_VERSION_MAJOR}_${LLVM_VERSION_MINOR}_${LLVM_VERSION_PATCH}_${LLVM_VERSION_SUFFIX}"
+  CACHE STRING "The namespace to use to enclose internal implementations. Must start with '__llvm_libc'."
+)
+
 if(LLVM_LIBC_FULL_BUILD OR LIBC_GPU_BUILD OR LIBC_GPU_ARCHITECTURES)
   if(NOT LIBC_HDRGEN_EXE)
     # We need to set up hdrgen first since other targets depend on it.
@@ -49,11 +54,6 @@ option(LIBC_CMAKE_VERBOSE_LOGGING
 # Path libc/scripts directory.
 set(LIBC_BUILD_SCRIPTS_DIR "${LIBC_SOURCE_DIR}/utils/build_scripts")
 
-# Defining a global namespace to enclose all libc functions.
-set(LIBC_NAMESPACE "__llvm_libc_${LLVM_VERSION_MAJOR}_${LLVM_VERSION_MINOR}_${LLVM_VERSION_PATCH}_${LLVM_VERSION_SUFFIX}"
-  CACHE STRING "The namespace to use to enclose internal implementations. Must start with '__llvm_libc'."
-)
-
 if(NOT LIBC_NAMESPACE MATCHES "^__llvm_libc")
   message(FATAL_ERROR "Invalid LIBC_NAMESPACE. Must start with '__llvm_libc' was '${LIBC_NAMESPACE}'")
 endif()
diff --git a/libc/utils/gpu/server/CMakeLists.txt b/libc/utils/gpu/server/CMakeLists.txt
index c802d79e63644a6..a1c4229d386f899 100644
--- a/libc/utils/gpu/server/CMakeLists.txt
+++ b/libc/utils/gpu/server/CMakeLists.txt
@@ -8,6 +8,8 @@ target_include_directories(llvmlibc_rpc_server PUBLIC ${CMAKE_CURRENT_SOURCE_DIR
 # Ignore unsupported clang attributes if we're using GCC.
 target_compile_options(llvmlibc_rpc_server PUBLIC
                        $<$<CXX_COMPILER_ID:GNU>:-Wno-attributes>)
+target_compile_definitions(llvmlibc_rpc_server PUBLIC
+                           LIBC_NAMESPACE=${LIBC_NAMESPACE})
 
 # Install the server and associated header.
 install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/rpc_server.h