diff options
28 files changed, 234 insertions, 6 deletions
diff --git a/Help/command/target_link_libraries.rst b/Help/command/target_link_libraries.rst index 393c8b4..d903d05 100644 --- a/Help/command/target_link_libraries.rst +++ b/Help/command/target_link_libraries.rst @@ -34,14 +34,20 @@ Each ``<item>`` may be: automatically be added in the build system to make sure the named library target is up-to-date before the ``<target>`` links. + If an imported library has the :prop_tgt:`IMPORTED_NO_SONAME` + target property set, CMake may ask the linker to search for + the library instead of using the full path + (e.g. ``/usr/lib/libfoo.so`` becomes ``-lfoo``). + * **A full path to a library file**: The generated link line will - normally preserve the full path to the file. However, there are - some cases where CMake must ask the linker to search for the library - (e.g. ``/usr/lib/libfoo.so`` becomes ``-lfoo``), such as when it - appears in a system library directory that the compiler front-end - may replace with an alternative. Either way, the buildsystem will + normally preserve the full path to the file. The buildsystem will have a dependency to re-link ``<target>`` if the library file changes. + There are some cases where CMake may ask the linker to search for + the library (e.g. ``/usr/lib/libfoo.so`` becomes ``-lfoo``), such + as when a shared library is detected to have no ``SONAME`` field. + See policy :policy:`CMP0060` for discussion of another case. + If the library file is in a Mac OSX framework, the ``Headers`` directory of the framework will also be processed as a :ref:`usage requirement <Target Usage Requirements>`. This has the same diff --git a/Help/manual/cmake-policies.7.rst b/Help/manual/cmake-policies.7.rst index d2960de..aff696d 100644 --- a/Help/manual/cmake-policies.7.rst +++ b/Help/manual/cmake-policies.7.rst @@ -117,3 +117,4 @@ All Policies /policy/CMP0057 /policy/CMP0058 /policy/CMP0059 + /policy/CMP0060 diff --git a/Help/policy/CMP0060.rst b/Help/policy/CMP0060.rst new file mode 100644 index 0000000..cc37b1b --- /dev/null +++ b/Help/policy/CMP0060.rst @@ -0,0 +1,63 @@ +CMP0060 +------- + +Link libraries by full path even in implicit directories. + +Policy :policy:`CMP0003` was introduced with the intention of always +linking library files by full path when a full path is given to the +:command:`target_link_libraries` command. However, on some platforms +(e.g. HP-UX) the compiler front-end adds alternative library search paths +for the current architecture (e.g. ``/usr/lib/<arch>`` has alternatives +to libraries in ``/usr/lib`` for the current architecture). +On such platforms the :command:`find_library` may find a library such as +``/usr/lib/libfoo.so`` that does not belong to the current architecture. + +Prior to policy :policy:`CMP0003` projects would still build in such +cases because the incorrect library path would be converted to ``-lfoo`` +on the link line and the linker would find the proper library in the +arch-specific search path provided by the compiler front-end implicitly. +At the time we chose to remain compatible with such projects by always +converting library files found in implicit link directories to ``-lfoo`` +flags to ask the linker to search for them. This approach allowed existing +projects to continue to build while still linking to libraries outside +implicit link directories via full path (such as those in the build tree). + +CMake does allow projects to override this behavior by using an +:ref:`IMPORTED library target <Imported Targets>` with its +:prop_tgt:`IMPORTED_LOCATION` property set to the desired full path to +a library file. In fact, many :ref:`Find Modules` are learning to provide +:ref:`Imported Targets` instead of just the traditional ``Foo_LIBRARIES`` +variable listing library files. However, this makes the link line +generated for a library found by a Find Module depend on whether it +is linked through an imported target or not, which is inconsistent. +Furthermore, this behavior has been a source of confusion because the +generated link line for a library file depends on its location. It is +also problematic for projects trying to link statically because flags +like ``-Wl,-Bstatic -lfoo -Wl,-Bdynamic`` may be used to help the linker +select ``libfoo.a`` instead of ``libfoo.so`` but then leak dynamic linking +to following libraries. (See the :prop_tgt:`LINK_SEARCH_END_STATIC` +target property for a solution typically used for that problem.) + +When the special case for libraries in implicit link directories was first +introduced the list of implicit link directories was simply hard-coded +(e.g. ``/lib``, ``/usr/lib``, and a few others). Since that time, CMake +has learned to detect the implicit link directories used by the compiler +front-end. If necessary, the :command:`find_library` command could be +taught to use this information to help find libraries of the proper +architecture. + +For these reasons, CMake 3.3 and above prefer to drop the special case +and link libraries by full path even when they are in implicit link +directories. Policy ``CMP0060`` provides compatibility for existing +projects. + +The OLD behavior for this policy is to ask the linker to search for +libraries whose full paths are known to be in implicit link directories. +The NEW behavior for this policy is to link libraries by full path even +if they are in implicit link directories. + +This policy was introduced in CMake version 3.3. Unlike most policies, +CMake version |release| does *not* warn by default when this policy +is not set and simply uses OLD behavior. See documentation of the +:variable:`CMAKE_POLICY_WARNING_CMP0060 <CMAKE_POLICY_WARNING_CMP<NNNN>>` +variable to control the warning. diff --git a/Help/release/dev/link-implicit-libs-full-path.rst b/Help/release/dev/link-implicit-libs-full-path.rst new file mode 100644 index 0000000..7ed7245 --- /dev/null +++ b/Help/release/dev/link-implicit-libs-full-path.rst @@ -0,0 +1,6 @@ +link-implicit-libs-full-path +---------------------------- + +* Linking to library files by a full path in an implicit linker search + directory (e.g. ``/usr/lib/libfoo.a``) no longer asks the linker to + search for the library (e.g. ``-lfoo``). See policy :policy:`CMP0060`. diff --git a/Help/variable/CMAKE_POLICY_WARNING_CMPNNNN.rst b/Help/variable/CMAKE_POLICY_WARNING_CMPNNNN.rst index a83c807..092fe3e 100644 --- a/Help/variable/CMAKE_POLICY_WARNING_CMPNNNN.rst +++ b/Help/variable/CMAKE_POLICY_WARNING_CMPNNNN.rst @@ -11,6 +11,8 @@ warn by default: policy :policy:`CMP0047`. * ``CMAKE_POLICY_WARNING_CMP0056`` controls the warning for policy :policy:`CMP0056`. +* ``CMAKE_POLICY_WARNING_CMP0060`` controls the warning for + policy :policy:`CMP0060`. This variable should not be set by a project in CMake code. Project developers running CMake may set this variable in their cache to diff --git a/Source/cmComputeLinkInformation.cxx b/Source/cmComputeLinkInformation.cxx index b0e0f36..8880667 100644 --- a/Source/cmComputeLinkInformation.cxx +++ b/Source/cmComputeLinkInformation.cxx @@ -411,6 +411,10 @@ cmComputeLinkInformation std::vector<std::string> const& dirs = this->Target->GetLinkDirectories(); this->OldLinkDirMask.insert(dirs.begin(), dirs.end()); } + + this->CMP0060Warn = + this->Makefile->PolicyOptionalWarningEnabled( + "CMAKE_POLICY_WARNING_CMP0060"); } //---------------------------------------------------------------------------- @@ -548,6 +552,22 @@ bool cmComputeLinkInformation::Compute() // Add implicit language runtime libraries and directories. this->AddImplicitLinkInfo(); + if (!this->CMP0060WarnItems.empty()) + { + std::ostringstream w; + w << (this->Makefile->GetCMakeInstance()->GetPolicies() + ->GetPolicyWarning(cmPolicies::CMP0060)) << "\n" + "Some library files are in directories implicitly searched by " + "the linker when invoked for " << this->LinkLanguage << ":\n" + " " << cmJoin(this->CMP0060WarnItems, "\n ") << "\n" + "For compatibility with older versions of CMake, the generated " + "link line will ask the linker to search for these by library " + "name." + ; + this->CMakeInstance->IssueMessage(cmake::AUTHOR_WARNING, w.str(), + this->Target->GetBacktrace()); + } + return true; } @@ -1190,6 +1210,28 @@ bool cmComputeLinkInformation::CheckImplicitDirItem(std::string const& item) return false; } + // Check the policy for whether we should use the approach below. + switch (this->Target->GetPolicyStatusCMP0060()) + { + case cmPolicies::WARN: + if (this->CMP0060Warn) + { + // Print the warning at most once for this item. + std::string const& wid = "CMP0060-WARNING-GIVEN-" + item; + if (!this->CMakeInstance->GetPropertyAsBool(wid)) + { + this->CMakeInstance->SetProperty(wid, "1"); + this->CMP0060WarnItems.insert(item); + } + } + case cmPolicies::OLD: + break; + case cmPolicies::REQUIRED_ALWAYS: + case cmPolicies::REQUIRED_IF_USED: + case cmPolicies::NEW: + return false; + } + // Many system linkers support multiple architectures by // automatically selecting the implicit linker search path for the // current architecture. If the library appears in an implicit link diff --git a/Source/cmComputeLinkInformation.h b/Source/cmComputeLinkInformation.h index e5d674a..8847141 100644 --- a/Source/cmComputeLinkInformation.h +++ b/Source/cmComputeLinkInformation.h @@ -175,6 +175,10 @@ private: std::vector<std::string> OldUserFlagItems; bool OldLinkDirMode; + // CMP0060 warnings. + bool CMP0060Warn; + std::set<std::string> CMP0060WarnItems; + // Runtime path computation. cmOrderDirectories* OrderRuntimeSearchPath; void AddLibraryRuntimeInfo(std::string const& fullPath, diff --git a/Source/cmPolicies.cxx b/Source/cmPolicies.cxx index 0a61bca..e7678cb 100644 --- a/Source/cmPolicies.cxx +++ b/Source/cmPolicies.cxx @@ -390,6 +390,11 @@ cmPolicies::cmPolicies() CMP0059, "CMP0059", "Do no treat DEFINITIONS as a built-in directory property.", 3,3,0, cmPolicies::WARN); + + this->DefinePolicy( + CMP0060, "CMP0060", + "Link libraries by full path even in implicit directories.", + 3,3,0, cmPolicies::WARN); } cmPolicies::~cmPolicies() diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h index ced9d8c..1d108c1 100644 --- a/Source/cmPolicies.h +++ b/Source/cmPolicies.h @@ -118,6 +118,7 @@ public: CMP0058, ///< Ninja requires custom command byproducts to be explicit CMP0059, ///< Do not treat ``DEFINITIONS`` as a built-in directory /// property. + CMP0060, ///< Link libraries by full path even in implicit directories. /** \brief Always the last entry. * diff --git a/Source/cmTarget.h b/Source/cmTarget.h index a4ef977..55bf234 100644 --- a/Source/cmTarget.h +++ b/Source/cmTarget.h @@ -34,7 +34,8 @@ F(CMP0041) \ F(CMP0042) \ F(CMP0046) \ - F(CMP0052) + F(CMP0052) \ + F(CMP0060) class cmake; class cmMakefile; diff --git a/Tests/RunCMake/CMP0060/CMP0060-Common.cmake b/Tests/RunCMake/CMP0060/CMP0060-Common.cmake new file mode 100644 index 0000000..e0a56e6 --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-Common.cmake @@ -0,0 +1,35 @@ +# Always build in a predictable configuration. For multi-config +# generators we depend on RunCMakeTest.cmake to do this for us. +if(NOT CMAKE_CONFIGURATION_TYPES) + set(CMAKE_BUILD_TYPE Debug) +endif() + +# Convince CMake that it can instruct the linker to search for the +# library of the proper linkage type, but do not really pass flags. +set(CMAKE_EXE_LINK_STATIC_C_FLAGS " ") +set(CMAKE_EXE_LINK_DYNAMIC_C_FLAGS " ") + +# Make a link line asking for the linker to search for the library +# look like a missing object file so we will get predictable content +# in the error message. This also ensures that cases expected to use +# the full path can be verified by confirming that they link. +set(CMAKE_LINK_LIBRARY_FLAG LINKFLAG_) +set(CMAKE_LINK_LIBRARY_SUFFIX _LINKSUFFIX${CMAKE_C_OUTPUT_EXTENSION}) + +# Convince CMake that our library is in an implicit linker search directory. +list(APPEND CMAKE_C_IMPLICIT_LINK_DIRECTORIES ${CMAKE_CURRENT_BINARY_DIR}/lib) + +# Create a simple library file. Place it in our library directory. +add_library(CMP0060 STATIC cmp0060.c) +set_property(TARGET CMP0060 PROPERTY + ARCHIVE_OUTPUT_DIRECTORY_DEBUG ${CMAKE_CURRENT_BINARY_DIR}/lib) + +# Add a target to link the library file by full path. +add_executable(main1 main.c) +target_link_libraries(main1 $<TARGET_FILE:CMP0060>) +add_dependencies(main1 CMP0060) + +# Add a second target to verify the warning only appears once. +add_executable(main2 main.c) +target_link_libraries(main2 $<TARGET_FILE:CMP0060>) +add_dependencies(main2 CMP0060) diff --git a/Tests/RunCMake/CMP0060/CMP0060-NEW.cmake b/Tests/RunCMake/CMP0060/CMP0060-NEW.cmake new file mode 100644 index 0000000..0414e4b --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-NEW.cmake @@ -0,0 +1,2 @@ +cmake_policy(SET CMP0060 NEW) +include(CMP0060-Common.cmake) diff --git a/Tests/RunCMake/CMP0060/CMP0060-OLD-Build-result.txt b/Tests/RunCMake/CMP0060/CMP0060-OLD-Build-result.txt new file mode 100644 index 0000000..d197c91 --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-OLD-Build-result.txt @@ -0,0 +1 @@ +[^0] diff --git a/Tests/RunCMake/CMP0060/CMP0060-OLD-Build-stdout.txt b/Tests/RunCMake/CMP0060/CMP0060-OLD-Build-stdout.txt new file mode 100644 index 0000000..240764c --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-OLD-Build-stdout.txt @@ -0,0 +1 @@ +LINKFLAG_CMP0060_LINKSUFFIX diff --git a/Tests/RunCMake/CMP0060/CMP0060-OLD.cmake b/Tests/RunCMake/CMP0060/CMP0060-OLD.cmake new file mode 100644 index 0000000..a9cffef --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-OLD.cmake @@ -0,0 +1,2 @@ +cmake_policy(SET CMP0060 OLD) +include(CMP0060-Common.cmake) diff --git a/Tests/RunCMake/CMP0060/CMP0060-WARN-OFF-Build-result.txt b/Tests/RunCMake/CMP0060/CMP0060-WARN-OFF-Build-result.txt new file mode 100644 index 0000000..d197c91 --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-WARN-OFF-Build-result.txt @@ -0,0 +1 @@ +[^0] diff --git a/Tests/RunCMake/CMP0060/CMP0060-WARN-OFF-Build-stdout.txt b/Tests/RunCMake/CMP0060/CMP0060-WARN-OFF-Build-stdout.txt new file mode 100644 index 0000000..240764c --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-WARN-OFF-Build-stdout.txt @@ -0,0 +1 @@ +LINKFLAG_CMP0060_LINKSUFFIX diff --git a/Tests/RunCMake/CMP0060/CMP0060-WARN-OFF.cmake b/Tests/RunCMake/CMP0060/CMP0060-WARN-OFF.cmake new file mode 100644 index 0000000..6b84565 --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-WARN-OFF.cmake @@ -0,0 +1 @@ +include(CMP0060-Common.cmake) diff --git a/Tests/RunCMake/CMP0060/CMP0060-WARN-ON-Build-result.txt b/Tests/RunCMake/CMP0060/CMP0060-WARN-ON-Build-result.txt new file mode 100644 index 0000000..d197c91 --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-WARN-ON-Build-result.txt @@ -0,0 +1 @@ +[^0] diff --git a/Tests/RunCMake/CMP0060/CMP0060-WARN-ON-Build-stdout.txt b/Tests/RunCMake/CMP0060/CMP0060-WARN-ON-Build-stdout.txt new file mode 100644 index 0000000..240764c --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-WARN-ON-Build-stdout.txt @@ -0,0 +1 @@ +LINKFLAG_CMP0060_LINKSUFFIX diff --git a/Tests/RunCMake/CMP0060/CMP0060-WARN-ON-stderr.txt b/Tests/RunCMake/CMP0060/CMP0060-WARN-ON-stderr.txt new file mode 100644 index 0000000..f6cc978 --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-WARN-ON-stderr.txt @@ -0,0 +1,16 @@ +^CMake Warning \(dev\) at CMP0060-Common.cmake:[0-9]+ \(add_executable\): + Policy CMP0060 is not set: Link libraries by full path even in implicit + directories. Run "cmake --help-policy CMP0060" for policy details. Use + the cmake_policy command to set the policy and suppress this warning. + + Some library files are in directories implicitly searched by the linker + when invoked for C: + + .*/Tests/RunCMake/CMP0060/CMP0060-WARN-ON-build/lib/(lib)?CMP0060.(a|lib) + + For compatibility with older versions of CMake, the generated link line + will ask the linker to search for these by library name. +Call Stack \(most recent call first\): + CMP0060-WARN-ON.cmake:[0-9]+ \(include\) + CMakeLists.txt:3 \(include\) +This warning is for project developers. Use -Wno-dev to suppress it.$ diff --git a/Tests/RunCMake/CMP0060/CMP0060-WARN-ON.cmake b/Tests/RunCMake/CMP0060/CMP0060-WARN-ON.cmake new file mode 100644 index 0000000..a0a7950 --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMP0060-WARN-ON.cmake @@ -0,0 +1,2 @@ +set(CMAKE_POLICY_WARNING_CMP0060 1) +include(CMP0060-Common.cmake) diff --git a/Tests/RunCMake/CMP0060/CMakeLists.txt b/Tests/RunCMake/CMP0060/CMakeLists.txt new file mode 100644 index 0000000..db6b701 --- /dev/null +++ b/Tests/RunCMake/CMP0060/CMakeLists.txt @@ -0,0 +1,3 @@ +cmake_minimum_required(VERSION 3.2) +project(${RunCMake_TEST} C) +include(${RunCMake_TEST}.cmake) diff --git a/Tests/RunCMake/CMP0060/RunCMakeTest.cmake b/Tests/RunCMake/CMP0060/RunCMakeTest.cmake new file mode 100644 index 0000000..445156f --- /dev/null +++ b/Tests/RunCMake/CMP0060/RunCMakeTest.cmake @@ -0,0 +1,19 @@ +include(RunCMake) + +function(run_cmake_CMP0060 CASE) + set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/CMP0060-${CASE}-build) + set(RunCMake_TEST_NO_CLEAN 1) + file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}") + file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}") + + run_cmake(CMP0060-${CASE}) + set(RunCMake_TEST_OUTPUT_MERGE 1) + run_cmake_command(CMP0060-${CASE}-Build + ${CMAKE_COMMAND} --build . --config Debug + ) +endfunction() + +run_cmake_CMP0060(OLD) +run_cmake_CMP0060(WARN-OFF) +run_cmake_CMP0060(WARN-ON) +run_cmake_CMP0060(NEW) diff --git a/Tests/RunCMake/CMP0060/cmp0060.c b/Tests/RunCMake/CMP0060/cmp0060.c new file mode 100644 index 0000000..a2da227 --- /dev/null +++ b/Tests/RunCMake/CMP0060/cmp0060.c @@ -0,0 +1,4 @@ +int libCMP0060(void) +{ + return 0; +} diff --git a/Tests/RunCMake/CMP0060/main.c b/Tests/RunCMake/CMP0060/main.c new file mode 100644 index 0000000..91848c2 --- /dev/null +++ b/Tests/RunCMake/CMP0060/main.c @@ -0,0 +1,5 @@ +extern int libCMP0060(void); +int main(void) +{ + return libCMP0060(); +} diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt index 60a8a82..e53612f 100644 --- a/Tests/RunCMake/CMakeLists.txt +++ b/Tests/RunCMake/CMakeLists.txt @@ -65,6 +65,7 @@ add_RunCMake_test(CMP0054) add_RunCMake_test(CMP0055) add_RunCMake_test(CMP0057) add_RunCMake_test(CMP0059) +add_RunCMake_test(CMP0060) if(CMAKE_GENERATOR STREQUAL "Ninja") add_RunCMake_test(Ninja) endif() diff --git a/Tests/RunCMake/TargetPolicies/PolicyList-stderr.txt b/Tests/RunCMake/TargetPolicies/PolicyList-stderr.txt index f4b744b..1da1623 100644 --- a/Tests/RunCMake/TargetPolicies/PolicyList-stderr.txt +++ b/Tests/RunCMake/TargetPolicies/PolicyList-stderr.txt @@ -17,6 +17,7 @@ \* CMP0042 \* CMP0046 \* CMP0052 + \* CMP0060 Call Stack \(most recent call first\): CMakeLists.txt:3 \(include\) |