e41e7b90f9
If a project depends on the Flang runtime and on libc++, linking fails because `std::__libcpp_verbose_abort` is defined in both libraries. Avoid that duplicate definition by defining `_LIBCPP_VERBOSE_ABORT` before including any C++ headers and by renaming that symbol in the Flang runtime to `flang_rt_verbose_abort`. The function that is modified was originally introduced in D158957 to solve an undefined symbol error when linking pure-Fortran projects with the Flang runtime. Providing a definition for that symbol in the Flang runtime might work correctly for ELF or Mach-O if that symbol has weak linkage in libc++. But at least for COFF, this now causes multiple-definition errors for projects that are linking to the Flang runtime and to libc++. The linker errors before this change for Windows/MinGW using Clang+Flang+lld look like this: ``` ld.lld: error: duplicate symbol: std::__1::__libcpp_verbose_abort(char const*, ...) >>> defined at libflang_rt.runtime.a(io-api-minimal.cpp.obj) >>> defined at libc++.dll.a(libc++.dll) ```
23 lines
730 B
C++
23 lines
730 B
C++
//===-- lib/runtime/stl-overrides.cpp ---------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include <cstdarg>
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#include <cstdio>
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#include <cstdlib>
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// Provide function that is used in place of `std::__libcpp_verbose_abort` to
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// avoid dependency on the symbol provided by libc++.
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void flang_rt_verbose_abort(char const *format, ...) {
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va_list list;
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va_start(list, format);
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std::vfprintf(stderr, format, list);
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va_end(list);
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std::abort();
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}
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