Commit 1d104f75 authored by Nicolai Hähnle's avatar Nicolai Hähnle
Browse files

Build fix: Turn off _GLIBCXX_DEBUG based on a compile check 

Summary:
Enabling _GLIBCXX_DEBUG (implied by LLVM_ENABLE_EXPENSIVE_CHECKS) causes
std::min_element (and presumably others) to no longer be constexpr, which
in turn causes the build to fail.

This seems like a bug in the GCC STL. This change works around it.

Change-Id: I5fc471caa9c4de3ef4e87aeeac8df1b960e8e72c

Reviewers: tstellar, hans, serge-sans-paille

Differential Revision: https://reviews.llvm.org/D75199
parent f5ad93d2

llvm/cmake/modules/HandleLLVMOptions.cmake

+16 −1
Original line number Diff line number Diff line
@@ -77,7 +77,22 @@ endif() 


if(LLVM_ENABLE_EXPENSIVE_CHECKS)

  add_definitions(-DEXPENSIVE_CHECKS)



  # In some libstdc++ versions, std::min_element is not constexpr when

  # _GLIBCXX_DEBUG is enabled.

  CHECK_CXX_SOURCE_COMPILES("

    #define _GLIBCXX_DEBUG

    #include <algorithm>

    int main(int argc, char** argv) {

      static constexpr int data[] = {0, 1};

      constexpr const int* min_elt = std::min_element(&data[0], &data[2]);

      return 0;

    }" CXX_SUPPORTS_GLIBCXX_DEBUG)

  if(CXX_SUPPORTS_GLIBCXX_DEBUG)

    add_definitions(-D_GLIBCXX_DEBUG)

  else()

    add_definitions(-D_GLIBCXX_ASSERTIONS)

  endif()

endif()



string(TOUPPER "${LLVM_ABI_BREAKING_CHECKS}" uppercase_LLVM_ABI_BREAKING_CHECKS)