Teach find_library and find_package to search lib32 paths (#11260)

Add a ``FIND_LIBRARY_USE_LIB32_PATHS`` global property analogous to the
``FIND_LIBRARY_USE_LIB64_PATHS`` property.  This helps find commands on
multilib systems that use ``lib32`` directories and either do not have
``lib`` symlinks or point ``lib`` to ``lib64``.

Help/command/find_library.rst

@@ -49,6 +49,13 @@ path to the framework ``<fullPath>/A.framework``.  When a full path to a
 framework is used as a library, CMake will use a ``-framework A``, and a
 ``-F<fullPath>`` to link the framework to the target.
 
+If the :prop_gbl:`FIND_LIBRARY_USE_LIB32_PATHS` global property is set
+all search paths will be tested as normal, with ``32/`` appended, and
+with all matches of ``lib/`` replaced with ``lib32/``.  This property is
+automatically set for the platforms that are known to need it if at
+least one of the languages supported by the :command:`project` command
+is enabled.
+
 If the :prop_gbl:`FIND_LIBRARY_USE_LIB64_PATHS` global property is set
 all search paths will be tested as normal, with ``64/`` appended, and
 with all matches of ``lib/`` replaced with ``lib64/``.  This property is

Help/manual/cmake-properties.7.rst

@@ -24,6 +24,7 @@ Properties of Global Scope
    /prop_gbl/DISABLED_FEATURES
    /prop_gbl/ENABLED_FEATURES
    /prop_gbl/ENABLED_LANGUAGES
+   /prop_gbl/FIND_LIBRARY_USE_LIB32_PATHS
    /prop_gbl/FIND_LIBRARY_USE_LIB64_PATHS
    /prop_gbl/FIND_LIBRARY_USE_OPENBSD_VERSIONING
    /prop_gbl/GLOBAL_DEPENDS_DEBUG_MODE

Help/prop_gbl/FIND_LIBRARY_USE_LIB32_PATHS.rst

@@ -0,0 +1,10 @@
+FIND_LIBRARY_USE_LIB32_PATHS
+----------------------------
+
+Whether the :command:`find_library` command should automatically search
+``lib32`` directories.
+
+``FIND_LIBRARY_USE_LIB32_PATHS`` is a boolean specifying whether the
+:command:`find_library` command should automatically search the ``lib32``
+variant of directories called ``lib`` in the search path when building 32-bit
+binaries.

Help/release/dev/find-lib32.rst

@@ -0,0 +1,7 @@
+find-lib32
+----------
+
+* The :command:`find_library` and :command:`find_package` commands learned
+  to search in ``lib32/`` directories when the build targets a 32-bit
+  architecture.  See the :prop_gbl:`FIND_LIBRARY_USE_LIB32_PATHS` global
+  property.

Modules/FindPkgConfig.cmake

@@ -316,9 +316,13 @@ macro(_pkg_check_modules_internal _is_required _is_silent _no_cmake_path _no_cma
             list(APPEND _lib_dirs "lib/${CMAKE_LIBRARY_ARCHITECTURE}/pkgconfig")
           endif()
         else()
-          # not debian, chech the FIND_LIBRARY_USE_LIB64_PATHS property
+          # not debian, check the FIND_LIBRARY_USE_LIB32_PATHS and FIND_LIBRARY_USE_LIB64_PATHS properties
+          get_property(uselib32 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS)
+          if(uselib32 AND CMAKE_SIZEOF_VOID_P EQUAL 4)
+            list(APPEND _lib_dirs "lib32/pkgconfig")
+          endif()
           get_property(uselib64 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS)
-          if(uselib64)
+          if(uselib64 AND CMAKE_SIZEOF_VOID_P EQUAL 8)
             list(APPEND _lib_dirs "lib64/pkgconfig")
           endif()
         endif()

Modules/Platform/Linux.cmake

@@ -50,8 +50,9 @@ set(CMAKE_LIBRARY_ARCHITECTURE_REGEX "[a-z0-9_]+(-[a-z0-9_]+)?-linux-gnu[a-z0-9_
 
 include(Platform/UnixPaths)
 
-# Debian has lib64 paths only for compatibility so they should not be
+# Debian has lib32 and lib64 paths only for compatibility so they should not be
 # searched.
 if(NOT CMAKE_CROSSCOMPILING AND EXISTS "/etc/debian_version")
+  set_property(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS FALSE)
   set_property(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS FALSE)
 endif()

Modules/Platform/OpenBSD.cmake

@@ -18,6 +18,7 @@ endif()
 set_property(GLOBAL PROPERTY FIND_LIBRARY_USE_OPENBSD_VERSIONING 1)
 
 # OpenBSD has no multilib
+set_property(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS FALSE)
 set_property(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS FALSE)
 
 # OpenBSD policy requires that shared libraries be installed without

Modules/Platform/UnixPaths.cmake

@@ -93,5 +93,6 @@ list(APPEND CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES
   /usr/include
   )
 
-# Enable use of lib64 search path variants by default.
+# Enable use of lib32 and lib64 search path variants by default.
+set_property(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS TRUE)
 set_property(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS TRUE)

Source/cmFindLibraryCommand.cxx

@@ -40,11 +40,10 @@ bool cmFindLibraryCommand::InitialPass(std::vector<std::string> const& argsIn,
     return true;
   }
 
-  if (const char* abi_name =
+  if (this->Makefile->GetState()->GetGlobalPropertyAsBool(
-        this->Makefile->GetDefinition("CMAKE_INTERNAL_PLATFORM_ABI")) {
+        "FIND_LIBRARY_USE_LIB32_PATHS")) {
-    std::string abi = abi_name;
+    // add special 32 bit paths if this is a 32 bit compile.
-    if (abi.find("ELF N32") != abi.npos) {
+    if (this->Makefile->PlatformIs32Bit()) {
-      // Convert lib to lib32.
       this->AddArchitecturePaths("32");
     }
   }

Source/cmFindPackageCommand.cxx

@@ -43,6 +43,7 @@ cmFindPackageCommand::cmFindPackageCommand()
   this->UseConfigFiles = true;
   this->UseFindModules = true;
   this->DebugMode = false;
+  this->UseLib32Paths = false;
   this->UseLib64Paths = false;
   this->PolicyScope = true;
   this->VersionMajor = 0;
@@ -110,6 +111,13 @@ bool cmFindPackageCommand::InitialPass(std::vector<std::string> const& args,
     this->LibraryArchitecture = arch;
   }
 
+  // Lookup whether lib32 paths should be used.
+  if (this->Makefile->PlatformIs32Bit() &&
+      this->Makefile->GetState()->GetGlobalPropertyAsBool(
+        "FIND_LIBRARY_USE_LIB32_PATHS")) {
+    this->UseLib32Paths = true;
+  }
+
   // Lookup whether lib64 paths should be used.
   if (this->Makefile->PlatformIs64Bit() &&
       this->Makefile->GetState()->GetGlobalPropertyAsBool(
@@ -1907,6 +1915,9 @@ bool cmFindPackageCommand::SearchPrefix(std::string const& prefix_in)
   if (!this->LibraryArchitecture.empty()) {
     common.push_back("lib/" + this->LibraryArchitecture);
   }
+  if (this->UseLib32Paths) {
+    common.push_back("lib32");
+  }
   if (this->UseLib64Paths) {
     common.push_back("lib64");
   }

Source/cmFindPackageCommand.h

@@ -148,6 +148,7 @@ private:
   bool NoUserRegistry;
   bool NoSystemRegistry;
   bool DebugMode;
+  bool UseLib32Paths;
   bool UseLib64Paths;
   bool PolicyScope;
   std::string LibraryArchitecture;

Source/cmMakefile.cxx

@@ -2076,6 +2076,14 @@ bool cmMakefile::IsSet(const std::string& name) const
   return true;
 }
 
+bool cmMakefile::PlatformIs32Bit() const
+{
+  if (const char* sizeof_dptr = this->GetDefinition("CMAKE_SIZEOF_VOID_P")) {
+    return atoi(sizeof_dptr) == 4;
+  }
+  return false;
+}
+
 bool cmMakefile::PlatformIs64Bit() const
 {
   if (const char* sizeof_dptr = this->GetDefinition("CMAKE_SIZEOF_VOID_P")) {

Source/cmMakefile.h

@@ -437,6 +437,9 @@ public:
   bool IsOn(const std::string& name) const;
   bool IsSet(const std::string& name) const;
 
+  /** Return whether the target platform is 32-bit. */
+  bool PlatformIs32Bit() const;
+
   /** Return whether the target platform is 64-bit.  */
   bool PlatformIs64Bit() const;
 

Tests/CMakeOnly/find_library/CMakeLists.txt

@@ -33,16 +33,23 @@ endmacro()
 
 set(CMAKE_FIND_LIBRARY_PREFIXES "lib")
 set(CMAKE_FIND_LIBRARY_SUFFIXES ".a")
+set_property(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS TRUE)
 set_property(GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS TRUE)
 
 set(CMAKE_SIZEOF_VOID_P 4)
 foreach(lib
+    lib/32/libtest5.a
     lib/A/lib/libtest1.a
+    lib/A/lib32/libtest3.a
     lib/A/libtest1.a
     lib/libtest1.a
     lib/libtest2.a
     lib/libtest3.a
     lib/libtest3.a
+    lib32/A/lib/libtest2.a
+    lib32/A/lib32/libtest4.a
+    lib32/A/libtest4.a
+    lib32/libtest4.a
     )
   test_find_library_subst(${lib})
 endforeach()

Tests/RunCMake/FindPkgConfig/FindPkgConfig_CMAKE_APPBUNDLE_PATH.cmake

@@ -1,4 +1,4 @@
-# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE and FIND_LIBRARY_USE_LIB64_PATHS
+# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE, FIND_LIBRARY_USE_LIB32_PATHS and FIND_LIBRARY_USE_LIB64_PATHS
 enable_language(C)
 
 # Prepare environment and variables
@@ -29,10 +29,15 @@ if(NOT DEFINED CMAKE_SYSTEM_NAME
       set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
     endif()
   else()
-    # not debian, chech the FIND_LIBRARY_USE_LIB64_PATHS property
+    # not debian, check the FIND_LIBRARY_USE_LIB32_PATHS and FIND_LIBRARY_USE_LIB64_PATHS properties
+    get_property(uselib32 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS)
     get_property(uselib64 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS)
-    if(uselib64)
+    if(uselib32 AND CMAKE_SIZEOF_VOID_P EQUAL 4)
+      set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib32/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib32/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
+    elseif(uselib64 AND CMAKE_SIZEOF_VOID_P EQUAL 8)
       set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib64/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib64/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
+    else()
+      set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
     endif()
   endif()
 else()

Tests/RunCMake/FindPkgConfig/FindPkgConfig_CMAKE_FRAMEWORK_PATH.cmake

@@ -1,4 +1,4 @@
-# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE and FIND_LIBRARY_USE_LIB64_PATHS
+# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE, FIND_LIBRARY_USE_LIB32_PATHS and FIND_LIBRARY_USE_LIB64_PATHS
 enable_language(C)
 
 # Prepare environment and variables
@@ -29,10 +29,15 @@ if(NOT DEFINED CMAKE_SYSTEM_NAME
       set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
     endif()
   else()
-    # not debian, chech the FIND_LIBRARY_USE_LIB64_PATHS property
+    # not debian, check the FIND_LIBRARY_USE_LIB64_PATHS and FIND_LIBRARY_USE_LIB64_PATHS properties
+    get_property(uselib32 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS)
     get_property(uselib64 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS)
-    if(uselib64)
+    if(uselib32 AND CMAKE_SIZEOF_VOID_P EQUAL 4)
+      set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib32/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib32/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
+    elseif(uselib64 AND CMAKE_SIZEOF_VOID_P EQUAL 8)
       set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib64/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib64/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
+    else()
+      set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
     endif()
   endif()
 else()

Tests/RunCMake/FindPkgConfig/FindPkgConfig_NO_PKGCONFIG_PATH.cmake

@@ -1,6 +1,3 @@
-# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE and FIND_LIBRARY_USE_LIB64_PATHS
-enable_language(C)
-
 # Prepare environment and variables
 set(PKG_CONFIG_USE_CMAKE_PREFIX_PATH FALSE)
 set(CMAKE_PREFIX_PATH "${CMAKE_CURRENT_SOURCE_DIR}/pc-foo")

Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH.cmake

@@ -1,4 +1,4 @@
-# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE and FIND_LIBRARY_USE_LIB64_PATHS
+# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE, FIND_LIBRARY_USE_LIB32_PATHS and FIND_LIBRARY_USE_LIB64_PATHS
 enable_language(C)
 
 # Prepare environment and variables
@@ -29,10 +29,15 @@ if(NOT DEFINED CMAKE_SYSTEM_NAME
       set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
     endif()
   else()
-    # not debian, chech the FIND_LIBRARY_USE_LIB64_PATHS property
+    # not debian, check the FIND_LIBRARY_USE_LIB32_PATHS and FIND_LIBRARY_USE_LIB64_PATHS propertie
+    get_property(uselib32 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS)
     get_property(uselib64 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS)
-    if(uselib64)
+    if(uselib32 AND CMAKE_SIZEOF_VOID_P EQUAL 4)
+      set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib32/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib32/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
+    elseif(uselib64 AND CMAKE_SIZEOF_VOID_P EQUAL 8)
       set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib64/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib64/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
+    else()
+      set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
     endif()
   endif()
 else()

Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH_NO_CMAKE_ENVIRONMENT_PATH.cmake

@@ -1,4 +1,4 @@
-# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE and FIND_LIBRARY_USE_LIB64_PATHS
+# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE, FIND_LIBRARY_USE_LIB32_PATHS and FIND_LIBRARY_USE_LIB64_PATHS
 enable_language(C)
 
 # Prepare environment and variables
@@ -29,10 +29,15 @@ if(NOT DEFINED CMAKE_SYSTEM_NAME
       set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig")
     endif()
   else()
-    # not debian, chech the FIND_LIBRARY_USE_LIB64_PATHS property
+    # not debian, check the FIND_LIBRARY_USE_LIB32_PATHS and FIND_LIBRARY_USE_LIB64_PATHS properties
+    get_property(uselib32 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS)
     get_property(uselib64 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS)
-    if(uselib64)
+    if(uselib32 AND CMAKE_SIZEOF_VOID_P EQUAL 4)
+      set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib32/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig")
+    elseif(uselib64 AND CMAKE_SIZEOF_VOID_P EQUAL 8)
       set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib64/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig")
+    else()
+      set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-foo/lib/pkgconfig")
     endif()
   endif()
 else()

Tests/RunCMake/FindPkgConfig/FindPkgConfig_PKGCONFIG_PATH_NO_CMAKE_PATH.cmake

@@ -1,4 +1,4 @@
-# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE and FIND_LIBRARY_USE_LIB64_PATHS
+# Needed for CMAKE_SYSTEM_NAME, CMAKE_LIBRARY_ARCHITECTURE, FIND_LIBRARY_USE_LIB32_PATHS and FIND_LIBRARY_USE_LIB64_PATHS
 enable_language(C)
 
 # Prepare environment and variables
@@ -29,10 +29,15 @@ if(NOT DEFINED CMAKE_SYSTEM_NAME
       set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
     endif()
   else()
-    # not debian, chech the FIND_LIBRARY_USE_LIB64_PATHS property
+    # not debian, check the FIND_LIBRARY_USE_LIB64_PATHS and FIND_LIBRARY_USE_LIB32_PATHS properties
+    get_property(uselib32 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB32_PATHS)
     get_property(uselib64 GLOBAL PROPERTY FIND_LIBRARY_USE_LIB64_PATHS)
-    if(uselib64)
+    if(uselib32 AND CMAKE_SIZEOF_VOID_P EQUAL 4)
+      set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib32/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
+    elseif(uselib64 AND CMAKE_SIZEOF_VOID_P EQUAL 8)
       set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib64/pkgconfig:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
+    else()
+      set(expected_path "/baz:${CMAKE_CURRENT_SOURCE_DIR}/pc-bar/lib/pkgconfig")
     endif()
   endif()
 else()