extra/llvm12: added shim (for rust)

1 files changed, 21 insertions, 0 deletions

diff --git a/extra/llvm12/add-fno-semantic-interposition.patch b/extra/llvm12/add-fno-semantic-interposition.patch
new file mode 100644
index 00000000..9edd3671
--- /dev/null
+++ b/extra/llvm12/add-fno-semantic-interposition.patch
@@ -0,0 +1,21 @@
+diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
+--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
++++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
+@@ -305,6 +305,17 @@
+     # On Windows all code is PIC. MinGW warns if -fPIC is used.
+   else()
+     add_flag_or_print_warning("-fPIC" FPIC)
++    # Enable interprocedural optimizations for non-inline functions which would
++    # otherwise be disabled due to GCC -fPIC's default.
++    #
++    # Note: Clang allows IPO for -fPIC so this optimization is less effective.
++    # Older Clang may support -fno-semantic-interposition but it used local
++    # aliases to optimize global variables, which is incompatible with copy
++    # relocations due to -fno-pic.
++    if (CMAKE_COMPILER_IS_GNUCXX OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND
++        CMAKE_CXX_COMPILER_VERSION GREATER_EQUAL 13))
++      add_flag_if_supported("-fno-semantic-interposition" FNO_SEMANTIC_INTERPOSITION)
++    endif()
+   endif()
+   # GCC for MIPS can miscompile LLVM due to PR37701.
+   if(CMAKE_COMPILER_IS_GNUCXX AND LLVM_NATIVE_ARCH STREQUAL "Mips" AND