[libc-commits] [libc] [llvm] [libc] Disable old headergen checks unless enabled (PR #104629)

[via libc-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: Michael Jones (michaelrj-google)

<details>
<summary>Changes</summary>

Old Headergen needed extra build rules to ensure that it worked in
runtimes mode. This patch disables those checks if new headergen is
enabled.


---
Full diff: https://github.com/llvm/llvm-project/pull/104629.diff


2 Files Affected:

- (modified) libc/CMakeLists.txt (+17-16) 
- (modified) llvm/runtimes/CMakeLists.txt (+2-1) 


``````````diff
diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
index dd45d6cc8cb6ab..133686acf6fa62 100644
--- a/libc/CMakeLists.txt
+++ b/libc/CMakeLists.txt
@@ -50,31 +50,32 @@ set(LIBC_NAMESPACE ${default_namespace}
   CACHE STRING "The namespace to use to enclose internal implementations. Must start with '__llvm_libc'."
 )
 
+option(LIBC_USE_NEW_HEADER_GEN "Generate header files using new headergen instead of the old one" ON)
 
-add_subdirectory(newhdrgen)
-
-
-if(LLVM_LIBC_FULL_BUILD OR LLVM_LIBC_GPU_BUILD)
-  if(NOT LIBC_HDRGEN_EXE)
-    # We need to set up hdrgen first since other targets depend on it.
-    add_subdirectory(utils/LibcTableGenUtil)
-    add_subdirectory(utils/HdrGen)
-    # Calling add_tablegen sets variables like LIBC_TABLEGEN_EXE in
-    # PARENT_SCOPE which get lost until saved in the cache.
-    set(LIBC_TABLEGEN_EXE "${LIBC_TABLEGEN_EXE}" CACHE INTERNAL "")
-    set(LIBC_TABLEGEN_TARGET "${LIBC_TABLEGEN_TARGET}" CACHE INTERNAL "")
-  else()
-    message(STATUS "Will use ${LIBC_HDRGEN_EXE} for libc header generation.")
+if(LIBC_USE_NEW_HEADER_GEN)
+  add_subdirectory(newhdrgen)
+else()
+  if(LLVM_LIBC_FULL_BUILD OR LLVM_LIBC_GPU_BUILD)
+    if(NOT LIBC_HDRGEN_EXE)
+      # We need to set up hdrgen first since other targets depend on it.
+      add_subdirectory(utils/LibcTableGenUtil)
+      add_subdirectory(utils/HdrGen)
+      # Calling add_tablegen sets variables like LIBC_TABLEGEN_EXE in
+      # PARENT_SCOPE which get lost until saved in the cache.
+      set(LIBC_TABLEGEN_EXE "${LIBC_TABLEGEN_EXE}" CACHE INTERNAL "")
+      set(LIBC_TABLEGEN_TARGET "${LIBC_TABLEGEN_TARGET}" CACHE INTERNAL "")
+    else()
+      message(STATUS "Will use ${LIBC_HDRGEN_EXE} for libc header generation.")
+    endif()
   endif()
 endif()
+
 # We will build the GPU utilities if we are not doing a runtimes build.
 option(LIBC_BUILD_GPU_LOADER "Always build the GPU loader utilities" OFF)
 if(LIBC_BUILD_GPU_LOADER OR (LLVM_LIBC_GPU_BUILD AND NOT LLVM_RUNTIMES_BUILD))
   add_subdirectory(utils/gpu)
 endif()
 
-option(LIBC_USE_NEW_HEADER_GEN "Generate header files using new headergen instead of the old one" ON)
-
 set(NEED_LIBC_HDRGEN FALSE)
 if(NOT LLVM_RUNTIMES_BUILD)
   if("libc" IN_LIST LLVM_ENABLE_RUNTIMES)
diff --git a/llvm/runtimes/CMakeLists.txt b/llvm/runtimes/CMakeLists.txt
index 187c44fb9d04d2..76202b2cfe0421 100644
--- a/llvm/runtimes/CMakeLists.txt
+++ b/llvm/runtimes/CMakeLists.txt
@@ -521,7 +521,8 @@ if(build_runtimes)
     endforeach()
   endif()
   if("libc" IN_LIST LLVM_ENABLE_PROJECTS AND
-      (LLVM_LIBC_FULL_BUILD OR LLVM_LIBC_GPU_BUILD))
+      (LLVM_LIBC_FULL_BUILD OR LLVM_LIBC_GPU_BUILD) AND 
+      (NOT LIBC_USE_NEW_HEADER_GEN))
     if(LIBC_HDRGEN_EXE)
       set(hdrgen_exe ${LIBC_HDRGEN_EXE})
     else()

``````````

</details>


https://github.com/llvm/llvm-project/pull/104629