Export the required symbol from DynamicLibraryTests

[chill]

Summary

Running unittests/Support/DynamicLibrary/DynamicLibraryTests fails
when LLVM is configured with -DLLVM_EXPORT_SYMBOLS_FOR_PLUGINS=ON, because
the test's version script only contains symbols extracted from the static libraries,
that the test links with, but not those from the main object/executable itself.

The patch moves the one symbol, needed by the test, to its own static library.

Fixes https://bugs.llvm.org/show_bug.cgi?id=32893

[rogfer01]

This LGTM, @marsupial what do you think?

[marsupial]

unittests/Support/DynamicLibrary/DynamicLibraryLib.cxx

1–12

Perhaps a more general filename (TestA.cpp) and use macros to determine the return value so this implementation can be used in other modules. This would allow for more testing/coverage in the future of other aspects of the DynamicLibrary manager (i.e. symbol resolution across multiple libs).

extern "C" PIPSQUEAK_EXPORT const char *TestA() {
#ifndef PIPSQUEAK_TESTA_RETURN
  return "ProcessCall";
#else
  return PIPSQUEAK_TESTA_RETURN;
#endif
}

PipSqueak.cxx

#define PIPSQUEAK_TESTA_RETURN "LibCall"
#include "TestA.cpp"

unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp

23

Might as well move this declaration to PipSqueak.h.

[marsupial]

unittests/Support/DynamicLibrary/DynamicLibraryLib.cxx

1–12

Actually ExportedSyms.cpp is probably a bit than TestA.cpp for when other functions/symbols are added.

[marsupial]

LGTM.

unittests/Support/DynamicLibrary/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS Support)
 
-add_llvm_unittest(DynamicLibraryTests DynamicLibraryTest.cpp)
+add_library(DynamicLibraryLib STATIC DynamicLibraryLib.cxx)
 
+add_llvm_unittest(DynamicLibraryTests DynamicLibraryTest.cpp)
+target_link_libraries(DynamicLibraryTests DynamicLibraryLib)
 export_executable_symbols(DynamicLibraryTests)
 
 add_library(PipSqueak SHARED PipSqueak.cxx)
 
 set_output_directory(PipSqueak
   BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}
   LIBRARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}
   )
 
 set_target_properties(PipSqueak
   PROPERTIES PREFIX ""
   SUFFIX ".so"
   )
 
 add_dependencies(DynamicLibraryTests PipSqueak)

unittests/Support/DynamicLibrary/DynamicLibraryLib.cxx

+//===- llvm/unittest/Support/DynamicLibrary/DynamicLibraryLib.cpp ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "PipSqueak.h"
+
+extern "C" PIPSQUEAK_EXPORT const char *TestA() { return "ProcessCall"; }

unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp

 #include "gtest/gtest.h"
 
 #include "PipSqueak.h"
 #include <string>
 
 using namespace llvm;
 using namespace llvm::sys;
 
-extern "C" PIPSQUEAK_EXPORT const char *TestA() { return "ProcessCall"; }
+extern "C" PIPSQUEAK_EXPORT const char *TestA();
 
 std::string LibPath() {
   const std::vector<testing::internal::string>& Argvs = testing::internal::GetArgvs();
   const char *Argv0 = Argvs.size() > 0 ? Argvs[0].c_str() : "DynamicLibraryTests";
   void *Ptr = (void*)(intptr_t)TestA;
   std::string Path = fs::getMainExecutable(Argv0, Ptr);
   llvm::SmallString<256> Buf(path::parent_path(Path));
   path::append(Buf, "PipSqueak.so");