[CMake] Use PRIVATE in target_link_libraries for executables

We currently use target_link_libraries without an explicit scope
specifier (INTERFACE, PRIVATE or PUBLIC) when linking executables.
Dependencies added in this way apply to both the target and its
dependencies, i.e. they become part of the executable's link interface
and are transitive.

Transitive dependencies generally don't make sense for executables,
since you wouldn't normally be linking against an executable. This also
causes issues for generating install export files when using
LLVM_DISTRIBUTION_COMPONENTS. For example, clang has a lot of LLVM
library dependencies, which are currently added as interface
dependencies. If clang is in the distribution components but the LLVM
libraries it depends on aren't (which is a perfectly legitimate use case
if the LLVM libraries are being built static and there are therefore no
run-time dependencies on them), CMake will complain about the LLVM
libraries not being in export set when attempting to generate the
install export file for clang. This is reasonable behavior on CMake's
part, and the right thing is for LLVM's build system to explicitly use
PRIVATE dependencies for executables.

Unfortunately, CMake doesn't allow you to mix and match the keyword and
non-keyword target_link_libraries signatures for a single target; i.e.,
if a single call to target_link_libraries for a particular target uses
one of the INTERFACE, PRIVATE, or PUBLIC keywords, all other calls must
also be updated to use those keywords. This means we must do this change
in a single shot. I also fully expect to have missed some instances; I
tested by enabling all the projects in the monorepo (except dragonegg),
and configuring both with and without shared libraries, on both Darwin
and Linux, but I'm planning to rely on the buildbots for other
configurations (since it should be pretty easy to fix those).

Even after this change, we still have a lot of target_link_libraries
calls that don't specify a scope keyword, mostly for shared libraries.
I'm thinking about addressing those in a follow-up, but that's a
separate change IMO.

Differential Revision: https://reviews.llvm.org/D40823



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319840 91177308-0d34-0410-b5e6-96231b3b80d8

Author: smeenai

cmake/modules/AddLLVM.cmake

@@ -768,7 +768,7 @@ macro(add_llvm_executable name)
     # libpthreads overrides some standard library symbols, so main
     # executable must be linked with it in order to provide consistent
     # API for all shared libaries loaded by this executable.
-    target_link_libraries(${name} ${LLVM_PTHREAD_LIB})
+    target_link_libraries(${name} PRIVATE ${LLVM_PTHREAD_LIB})
   endif()
 endmacro(add_llvm_executable name)
 
@@ -1093,7 +1093,7 @@ function(add_unittest test_suite test_name)
   # libpthreads overrides some standard library symbols, so main
   # executable must be linked with it in order to provide consistent
   # API for all shared libaries loaded by this executable.
-  target_link_libraries(${test_name} gtest_main gtest ${LLVM_PTHREAD_LIB})
+  target_link_libraries(${test_name} PRIVATE gtest_main gtest ${LLVM_PTHREAD_LIB})
 
   add_dependencies(${test_suite} ${test_name})
   get_target_property(test_suite_folder ${test_suite} FOLDER)

cmake/modules/LLVM-Config.cmake

@@ -87,7 +87,7 @@ macro(llvm_config executable)
       endif()
     endif()
 
-    target_link_libraries(${executable} LLVM)
+    target_link_libraries(${executable} PRIVATE LLVM)
   endif()
 
   explicit_llvm_config(${executable} ${link_components})
@@ -101,7 +101,7 @@ function(explicit_llvm_config executable)
   get_target_property(t ${executable} TYPE)
   if(t STREQUAL "STATIC_LIBRARY")
     target_link_libraries(${executable} INTERFACE ${LIBRARIES})
-  elseif(t STREQUAL "SHARED_LIBRARY" OR t STREQUAL "MODULE_LIBRARY")
+  elseif(t STREQUAL "EXECUTABLE" OR t STREQUAL "SHARED_LIBRARY" OR t STREQUAL "MODULE_LIBRARY")
     target_link_libraries(${executable} PRIVATE ${LIBRARIES})
   else()
     # Use plain form for legacy user.

examples/ParallelJIT/CMakeLists.txt

@@ -11,4 +11,4 @@ add_llvm_example(ParallelJIT
   ParallelJIT.cpp
   )
 
-target_link_libraries(ParallelJIT ${LLVM_PTHREAD_LIB})
+target_link_libraries(ParallelJIT PRIVATE ${LLVM_PTHREAD_LIB})

tools/bugpoint/CMakeLists.txt

@@ -37,7 +37,7 @@ add_llvm_tool(bugpoint
 export_executable_symbols(bugpoint)
 
 if(WITH_POLLY AND LINK_POLLY_INTO_TOOLS)
-  target_link_libraries(bugpoint Polly)
+  target_link_libraries(bugpoint PRIVATE Polly)
   # Ensure LLVMTarget can resolve dependences in Polly.
-  target_link_libraries(bugpoint LLVMTarget)
+  target_link_libraries(bugpoint PRIVATE LLVMTarget)
 endif(WITH_POLLY AND LINK_POLLY_INTO_TOOLS)

tools/dsymutil/CMakeLists.txt

@@ -22,5 +22,5 @@ add_llvm_tool(llvm-dsymutil
   )
 
 IF(APPLE)
-  target_link_libraries(llvm-dsymutil "-framework CoreFoundation")
+  target_link_libraries(llvm-dsymutil PRIVATE "-framework CoreFoundation")
 ENDIF(APPLE)

tools/llvm-cfi-verify/CMakeLists.txt

@@ -15,4 +15,4 @@ add_llvm_tool(llvm-cfi-verify
   llvm-cfi-verify.cpp)
 
 add_subdirectory(lib)
-target_link_libraries(llvm-cfi-verify LLVMCFIVerify)
+target_link_libraries(llvm-cfi-verify PRIVATE LLVMCFIVerify)

tools/llvm-objdump/CMakeLists.txt

@@ -23,7 +23,7 @@ add_llvm_tool(llvm-objdump
   )
 
 if(HAVE_LIBXAR)
-  target_link_libraries(llvm-objdump ${XAR_LIB})
+  target_link_libraries(llvm-objdump PRIVATE ${XAR_LIB})
 endif()
 
 if(LLVM_INSTALL_BINUTILS_SYMLINKS)

tools/opt/CMakeLists.txt

@@ -37,5 +37,5 @@ add_llvm_tool(opt
 export_executable_symbols(opt)
 
 if(WITH_POLLY AND LINK_POLLY_INTO_TOOLS)
-  target_link_libraries(opt Polly)
+  target_link_libraries(opt PRIVATE Polly)
 endif(WITH_POLLY AND LINK_POLLY_INTO_TOOLS)

unittests/DebugInfo/CodeView/CMakeLists.txt

@@ -11,4 +11,4 @@ add_llvm_unittest(DebugInfoCodeViewTests
   ${DebugInfoCodeViewSources}
   )
 
-target_link_libraries(DebugInfoCodeViewTests LLVMTestingSupport)
+target_link_libraries(DebugInfoCodeViewTests PRIVATE LLVMTestingSupport)

unittests/DebugInfo/DWARF/CMakeLists.txt

@@ -18,4 +18,4 @@ add_llvm_unittest(DebugInfoDWARFTests
   ${DebugInfoSources}
   )
 
-target_link_libraries(DebugInfoDWARFTests LLVMTestingSupport)
+target_link_libraries(DebugInfoDWARFTests PRIVATE LLVMTestingSupport)

unittests/DebugInfo/MSF/CMakeLists.txt

@@ -12,4 +12,4 @@ add_llvm_unittest(DebugInfoMSFTests
   ${DebugInfoMSFSources}
   )
 
-target_link_libraries(DebugInfoMSFTests LLVMTestingSupport)
+target_link_libraries(DebugInfoMSFTests PRIVATE LLVMTestingSupport)

unittests/DebugInfo/PDB/CMakeLists.txt

@@ -14,4 +14,4 @@ add_llvm_unittest(DebugInfoPDBTests
   ${DebugInfoPDBSources}
   )
 
-target_link_libraries(DebugInfoPDBTests LLVMTestingSupport)
+target_link_libraries(DebugInfoPDBTests PRIVATE LLVMTestingSupport)

unittests/ExecutionEngine/Orc/CMakeLists.txt

@@ -24,4 +24,4 @@ add_llvm_unittest(OrcJITTests
   SymbolStringPoolTest.cpp
   )
 
-target_link_libraries(OrcJITTests ${LLVM_PTHREAD_LIB})
+target_link_libraries(OrcJITTests PRIVATE ${LLVM_PTHREAD_LIB})

unittests/ProfileData/CMakeLists.txt

@@ -11,4 +11,4 @@ add_llvm_unittest(ProfileDataTests
   SampleProfTest.cpp
   )
 
-target_link_libraries(ProfileDataTests LLVMTestingSupport)
+target_link_libraries(ProfileDataTests PRIVATE LLVMTestingSupport)

unittests/Support/CMakeLists.txt

@@ -74,6 +74,6 @@ add_llvm_unittest(SupportTests
 set_source_files_properties(AlignOfTest.cpp PROPERTIES COMPILE_FLAGS -w)
 
 # ManagedStatic.cpp uses <pthread>.
-target_link_libraries(SupportTests LLVMTestingSupport ${LLVM_PTHREAD_LIB})
+target_link_libraries(SupportTests PRIVATE LLVMTestingSupport ${LLVM_PTHREAD_LIB})
 
 add_subdirectory(DynamicLibrary)

unittests/Support/DynamicLibrary/CMakeLists.txt

@@ -4,7 +4,7 @@ add_library(DynamicLibraryLib STATIC ExportedFuncs.cxx)
 set_target_properties(DynamicLibraryLib PROPERTIES FOLDER "Tests")
 
 add_llvm_unittest(DynamicLibraryTests DynamicLibraryTest.cpp)
-target_link_libraries(DynamicLibraryTests DynamicLibraryLib)
+target_link_libraries(DynamicLibraryTests PRIVATE DynamicLibraryLib)
 export_executable_symbols(DynamicLibraryTests)
 
 function(dynlib_add_module NAME)

unittests/tools/llvm-cfi-verify/CMakeLists.txt

@@ -14,4 +14,4 @@ set(LLVM_LINK_COMPONENTS
 add_llvm_unittest(CFIVerifyTests
   FileAnalysis.cpp
   GraphBuilder.cpp)
-target_link_libraries(CFIVerifyTests LLVMCFIVerify)
+target_link_libraries(CFIVerifyTests PRIVATE LLVMCFIVerify)

utils/FileCheck/CMakeLists.txt

@@ -2,4 +2,4 @@ add_llvm_utility(FileCheck
   FileCheck.cpp
   )
 
-target_link_libraries(FileCheck LLVMSupport)
+target_link_libraries(FileCheck PRIVATE LLVMSupport)

utils/not/CMakeLists.txt

@@ -2,4 +2,4 @@ add_llvm_utility(not
   not.cpp
   )
 
-target_link_libraries(not LLVMSupport)
+target_link_libraries(not PRIVATE LLVMSupport)

utils/yaml-bench/CMakeLists.txt

@@ -2,4 +2,4 @@ add_llvm_utility(yaml-bench
   YAMLBench.cpp
   )
 
-target_link_libraries(yaml-bench LLVMSupport)
+target_link_libraries(yaml-bench PRIVATE LLVMSupport)