[PATCH] D102090: [CMake][ELF] Add -fno-semantic-interposition and -Bsymbolic-functions

[Fangrui Song via Phabricator via cfe-commits]

MaskRay updated this revision to Diff 343755.
MaskRay added a comment.

Set global CMAKE_SHARED_LINKER_FLAGS instead.

This additional makes -DBUILD_SHARED_LIBS=on builds (dev only; not recommended for packagers) faster.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102090/new/

https://reviews.llvm.org/D102090

Files:
  llvm/cmake/modules/HandleLLVMOptions.cmake


Index: llvm/cmake/modules/HandleLLVMOptions.cmake
===================================================================
--- llvm/cmake/modules/HandleLLVMOptions.cmake
+++ llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -237,6 +237,12 @@
   set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} -Wl,-z,nodelete")
 endif()
 
+# Optimize function calls and global variable access for default visibility
+# definitions to avoid PLT and reduce dynamic relocations.
+if(${CMAKE_SYSTEM_NAME} MATCHES "DragonFly|FreeBSD|Fuchsia|Linux|NetBSD|OpenBSD")
+  set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -Wl,-Bsymbolic-functions")
+endif()
+
 
 function(append value)
   foreach(variable ${ARGN})
@@ -305,6 +311,7 @@
     # On Windows all code is PIC. MinGW warns if -fPIC is used.
   else()
     add_flag_or_print_warning("-fPIC" FPIC)
+    add_flag_if_supported("-fno-semantic-interposition" FNO_SEMANTIC_INTERPOSITION)
   endif()
   # GCC for MIPS can miscompile LLVM due to PR37701.
   if(CMAKE_COMPILER_IS_GNUCXX AND LLVM_NATIVE_ARCH STREQUAL "Mips" AND


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