Add linker scripts with symbol versioning (#721)

Both the Autoconf and CMake build systems are updated to detect linker support for symbol versioning.

Currently, Linux, Solaris, and FreeBSD are tested and working. Windows (COFF) and macOS (Mach-O) have no symbol versioning.

There is an Autoconf/CMake flag to opt out of the versioning behaviour.

Author: NWilson

CMakeLists.txt

@@ -108,7 +108,8 @@
 # Applied to all CMake files using:
 #    > pip3 install gersemi
 #    > gersemi --in-place --line-length 120 --indent 2 \
-#          ./CMakeLists.txt ./cmake/*.cmake ./cmake/*.cmake.in
+#          --definitions cmake/*.cmake \
+#          -- ./CMakeLists.txt ./cmake/*.cmake ./cmake/*.cmake.in
 ################################################################################
 
 # Increased minimum to 3.15 to allow use of string(REPEAT).
@@ -123,10 +124,12 @@ set(CMAKE_C_VISIBILITY_PRESET hidden)
 # recently added to CMake for the `cc` compiler (Oracle Developer Studio). The
 # CMake version from OpenCSW and Oracle's package repository is too old and
 # requires this fix.
-if (CMAKE_SYSTEM_NAME STREQUAL "SunOS" AND
-    CMAKE_VERSION VERSION_LESS 3.31 AND
-    CMAKE_C_COMPILER_ID STREQUAL "SunPro" AND
-    CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 5.15)
+if(
+  CMAKE_SYSTEM_NAME STREQUAL "SunOS"
+  AND CMAKE_VERSION VERSION_LESS 3.31
+  AND CMAKE_C_COMPILER_ID STREQUAL "SunPro"
+  AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 5.15
+)
   set(CMAKE_C_COMPILE_OPTIONS_VISIBILITY "-fvisibility=")
 endif()
 
@@ -158,6 +161,7 @@ include(CheckSymbolExists)
 include(CheckIncludeFile)
 include(CheckTypeSize)
 include(GNUInstallDirs) # for CMAKE_INSTALL_LIBDIR
+include(PCRE2CheckLinkerFlag)
 
 check_include_file(assert.h HAVE_ASSERT_H)
 check_include_file(dirent.h HAVE_DIRENT_H)
@@ -200,6 +204,12 @@ check_c_source_compiles(
   HAVE_VISIBILITY
 )
 
+if(HAVE_VISIBILITY)
+  set(PCRE2_EXPORT [=[__attribute__ ((visibility ("default")))]=])
+else()
+  set(PCRE2_EXPORT)
+endif()
+
 set(CMAKE_REQUIRED_FLAGS ${ORIG_CMAKE_REQUIRED_FLAGS})
 
 check_c_source_compiles("int main(void) { __assume(1); return 0; }" HAVE_BUILTIN_ASSUME)
@@ -217,11 +227,33 @@ check_c_source_compiles(
   HAVE_BUILTIN_UNREACHABLE
 )
 
-if(HAVE_VISIBILITY)
-  set(PCRE2_EXPORT [=[__attribute__ ((visibility ("default")))]=])
-else()
-  set(PCRE2_EXPORT)
+# Detect support for linker scripts.
+
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/test-map-file.sym "PCRE2_10.00 { global: main; };")
+file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/test-map-file-broken.sym "PCRE2_10.00 { global: main; };  {")
+pcre2_check_linker_flag(C -Wl,--version-script,${CMAKE_CURRENT_BINARY_DIR}/test-map-file.sym HAVE_VSCRIPT_GNU)
+pcre2_check_linker_flag(C -Wl,-M,${CMAKE_CURRENT_BINARY_DIR}/test-map-file.sym HAVE_VSCRIPT_SUN)
+if(HAVE_VSCRIPT_GNU)
+  set(VSCRIPT_FLAG --version-script)
+  set(HAVE_VSCRIPT TRUE)
+elseif(HAVE_VSCRIPT_SUN)
+  set(VSCRIPT_FLAG -M)
+  set(HAVE_VSCRIPT TRUE)
+endif()
+if(HAVE_VSCRIPT)
+  # Perform the same logic as ax_check_vscript.m4, to test whether the linker
+  # silently ignores (and overwrites) linker scripts it doesn't understand.
+  pcre2_check_linker_flag(
+    C
+    -Wl,${VSCRIPT_FLAG},${CMAKE_CURRENT_BINARY_DIR}/test-map-file-broken.sym
+    HAVE_VSCRIPT_BROKEN
+  )
+  if(HAVE_VSCRIPT_BROKEN)
+    set(HAVE_VSCRIPT FALSE)
+  endif()
 endif()
+file(REMOVE ${CMAKE_CURRENT_BINARY_DIR}/test-map-file.sym)
+file(REMOVE ${CMAKE_CURRENT_BINARY_DIR}/test-map-file-broken.sym)
 
 # Check whether Intel CET is enabled, and if so, adjust compiler flags. This
 # code was written by PH, trying to imitate the logic from the autotools
@@ -272,7 +304,12 @@ set(
 
 set(PCRE2_EBCDIC_NL25 OFF CACHE BOOL "Use 0x25 as EBCDIC NL character instead of 0x15; implies EBCDIC.")
 
-set(PCRE2_EBCDIC_IGNORING_COMPILER OFF CACHE BOOL "Force EBCDIC 1047 using numeric literals rather than C character literals; implies EBCDIC.")
+set(
+  PCRE2_EBCDIC_IGNORING_COMPILER
+  OFF
+  CACHE BOOL
+  "Force EBCDIC 1047 using numeric literals rather than C character literals; implies EBCDIC."
+)
 
 option(PCRE2_REBUILD_CHARTABLES "Rebuild char tables" OFF)
 
@@ -388,6 +425,10 @@ if(MSVC)
   option(INSTALL_MSVC_PDB "ON=Install .pdb files built by MSVC, if generated" OFF)
 endif()
 
+if(HAVE_VSCRIPT)
+  option(PCRE2_SYMVERS "Enable library symbol versioning" ON)
+endif()
+
 # bzip2 lib
 if(BZIP2_FOUND)
   option(PCRE2_SUPPORT_LIBBZ2 "Enable support for linking pcre2grep with libbz2." ON)
@@ -705,9 +746,17 @@ if(REBUILD_CHARTABLES)
 elseif(NOT PCRE2_EBCDIC)
   configure_file(${PROJECT_SOURCE_DIR}/src/pcre2_chartables.c.dist ${PROJECT_BINARY_DIR}/pcre2_chartables.c COPYONLY)
 elseif(PCRE2_EBCDIC_NL25)
-  configure_file(${PROJECT_SOURCE_DIR}/src/pcre2_chartables.c.ebcdic-1047-nl25 ${PROJECT_BINARY_DIR}/pcre2_chartables.c COPYONLY)
+  configure_file(
+    ${PROJECT_SOURCE_DIR}/src/pcre2_chartables.c.ebcdic-1047-nl25
+    ${PROJECT_BINARY_DIR}/pcre2_chartables.c
+    COPYONLY
+  )
 else()
-  configure_file(${PROJECT_SOURCE_DIR}/src/pcre2_chartables.c.ebcdic-1047-nl15 ${PROJECT_BINARY_DIR}/pcre2_chartables.c COPYONLY)
+  configure_file(
+    ${PROJECT_SOURCE_DIR}/src/pcre2_chartables.c.ebcdic-1047-nl15
+    ${PROJECT_BINARY_DIR}/pcre2_chartables.c
+    COPYONLY
+  )
 endif()
 
 # Source code
@@ -882,6 +931,10 @@ if(PCRE2_BUILD_PCRE2_8)
     if(REQUIRE_PTHREAD)
       target_link_libraries(pcre2-8-shared Threads::Threads)
     endif()
+    if(HAVE_VSCRIPT AND PCRE2_SYMVERS)
+      target_link_options(pcre2-8-shared PRIVATE -Wl,${VSCRIPT_FLAG},${PROJECT_SOURCE_DIR}/src/libpcre2-8.sym)
+      set_target_properties(pcre2-8-shared PROPERTIES LINK_DEPENDS ${PROJECT_SOURCE_DIR}/src/libpcre2-8.sym)
+    endif()
     set(TARGETS ${TARGETS} pcre2-8-shared)
     set(DLL_PDB_FILES $<TARGET_PDB_FILE_DIR:pcre2-8-shared>/pcre2-8.pdb ${DLL_PDB_FILES})
     set(DLL_PDB_DEBUG_FILES $<TARGET_PDB_FILE_DIR:pcre2-8-shared>/pcre2-8d.pdb ${DLL_PDB_DEBUG_FILES})
@@ -898,6 +951,10 @@ if(PCRE2_BUILD_PCRE2_8)
         SOVERSION ${LIBPCRE2_POSIX_SOVERSION}
         OUTPUT_NAME pcre2-posix
     )
+    if(HAVE_VSCRIPT AND PCRE2_SYMVERS)
+      target_link_options(pcre2-posix-shared PRIVATE -Wl,${VSCRIPT_FLAG},${PROJECT_SOURCE_DIR}/src/libpcre2-posix.sym)
+      set_target_properties(pcre2-posix-shared PROPERTIES LINK_DEPENDS ${PROJECT_SOURCE_DIR}/src/libpcre2-posix.sym)
+    endif()
     set(PCRE2POSIX_CFLAG "-DPCRE2POSIX_SHARED")
     target_compile_definitions(pcre2-posix-shared PUBLIC ${PCRE2POSIX_CFLAG})
     target_link_libraries(pcre2-posix-shared pcre2-8-shared)
@@ -971,6 +1028,10 @@ if(PCRE2_BUILD_PCRE2_16)
     if(REQUIRE_PTHREAD)
       target_link_libraries(pcre2-16-shared Threads::Threads)
     endif()
+    if(HAVE_VSCRIPT AND PCRE2_SYMVERS)
+      target_link_options(pcre2-16-shared PRIVATE -Wl,${VSCRIPT_FLAG},${PROJECT_SOURCE_DIR}/src/libpcre2-16.sym)
+      set_target_properties(pcre2-16-shared PROPERTIES LINK_DEPENDS ${PROJECT_SOURCE_DIR}/src/libpcre2-16.sym)
+    endif()
     set(TARGETS ${TARGETS} pcre2-16-shared)
     set(DLL_PDB_FILES $<TARGET_PDB_FILE_DIR:pcre2-16-shared>/pcre2-16.pdb ${DLL_PDB_FILES})
     set(DLL_PDB_DEBUG_FILES $<TARGET_PDB_FILE_DIR:pcre2-16-shared>/pcre2-16d.pdb ${DLL_PDB_DEBUG_FILES})
@@ -1039,6 +1100,10 @@ if(PCRE2_BUILD_PCRE2_32)
     if(REQUIRE_PTHREAD)
       target_link_libraries(pcre2-32-shared Threads::Threads)
     endif()
+    if(HAVE_VSCRIPT AND PCRE2_SYMVERS)
+      target_link_options(pcre2-32-shared PRIVATE -Wl,${VSCRIPT_FLAG},${PROJECT_SOURCE_DIR}/src/libpcre2-32.sym)
+      set_target_properties(pcre2-32-shared PROPERTIES LINK_DEPENDS ${PROJECT_SOURCE_DIR}/src/libpcre2-32.sym)
+    endif()
     set(TARGETS ${TARGETS} pcre2-32-shared)
     set(DLL_PDB_FILES $<TARGET_PDB_FILE_DIR:pcre2-32-shared>/pcre2-32.pdb ${DLL_PDB_FILES})
     set(DLL_PDB_DEBUG_FILES $<TARGET_PDB_FILE_DIR:pcre2-32-shared>/pcre2-32d.pdb ${DLL_PDB_DEBUG_FILES})
@@ -1372,9 +1437,9 @@ if(PCRE2_SHOW_REPORT)
   else()
     message(STATUS "  Build type ........................ : ${CMAKE_BUILD_TYPE}")
   endif()
-  message(STATUS "  Build 8 bit PCRE2 library ......... : ${PCRE2_BUILD_PCRE2_8}")
-  message(STATUS "  Build 16 bit PCRE2 library ........ : ${PCRE2_BUILD_PCRE2_16}")
-  message(STATUS "  Build 32 bit PCRE2 library ........ : ${PCRE2_BUILD_PCRE2_32}")
+  message(STATUS "  Build 8 bit pcre2 library ......... : ${PCRE2_BUILD_PCRE2_8}")
+  message(STATUS "  Build 16 bit pcre2 library ........ : ${PCRE2_BUILD_PCRE2_16}")
+  message(STATUS "  Build 32 bit pcre2 library ........ : ${PCRE2_BUILD_PCRE2_32}")
   message(STATUS "  Include debugging code ............ : ${PCRE2_DEBUG}")
   message(STATUS "  Enable JIT compiling support ...... : ${PCRE2_SUPPORT_JIT}")
   message(STATUS "  Use SELinux allocator in JIT ...... : ${PCRE2_SUPPORT_JIT_SEALLOC}")
@@ -1397,18 +1462,24 @@ if(PCRE2_SHOW_REPORT)
 
   message(STATUS "  Internal link size ................ : ${PCRE2_LINK_SIZE}")
   message(STATUS "  Maximum variable lookbehind ....... : ${PCRE2_MAX_VARLOOKBEHIND}")
-  message(STATUS "  Parentheses nest limit ............ : ${PCRE2_PARENS_NEST_LIMIT}")
+  message(STATUS "  Nested parentheses limit .......... : ${PCRE2_PARENS_NEST_LIMIT}")
   message(STATUS "  Heap limit ........................ : ${PCRE2_HEAP_LIMIT}")
   message(STATUS "  Match limit ....................... : ${PCRE2_MATCH_LIMIT}")
   message(STATUS "  Match depth limit ................. : ${PCRE2_MATCH_LIMIT_DEPTH}")
   message(STATUS "  Build shared libs ................. : ${BUILD_SHARED_LIBS}")
+  if(NOT HAVE_VSCRIPT)
+    message(STATUS "      with symbol versioning ........ : n/a")
+  else()
+    message(STATUS "      with symbol versioning ........ : ${PCRE2_SYMVERS}")
+  endif()
   message(STATUS "  Build static libs ................. : ${BUILD_STATIC_LIBS}")
-  message(STATUS "     with PIC enabled ............... : ${PCRE2_STATIC_PIC}")
+  message(STATUS "      with PIC enabled .............. : ${PCRE2_STATIC_PIC}")
   message(STATUS "  Build pcre2grep ................... : ${PCRE2_BUILD_PCRE2GREP}")
   message(STATUS "  Enable JIT in pcre2grep ........... : ${PCRE2GREP_SUPPORT_JIT}")
   message(STATUS "  Enable callouts in pcre2grep ...... : ${PCRE2GREP_SUPPORT_CALLOUT}")
   message(STATUS "  Enable callout fork in pcre2grep .. : ${PCRE2GREP_SUPPORT_CALLOUT_FORK}")
-  message(STATUS "  Buffer size for pcre2grep ......... : ${PCRE2GREP_BUFSIZE}")
+  message(STATUS "  Initial buffer size for pcre2grep . : ${PCRE2GREP_BUFSIZE}")
+  message(STATUS "  Maximum buffer size for pcre2grep . : ${PCRE2GREP_MAX_BUFSIZE}")
   message(STATUS "  Build tests (implies pcre2test .... : ${PCRE2_BUILD_TESTS}")
   message(STATUS "               and pcre2grep)")
   if(ZLIB_FOUND)
@@ -1431,7 +1502,7 @@ if(PCRE2_SHOW_REPORT)
   else()
     message(STATUS "  Link pcre2test with libreadline ... : Library not found")
   endif()
-  message(STATUS "  Support Valgrind .................. : ${PCRE2_SUPPORT_VALGRIND}")
+  message(STATUS "  Enable Valgrind support ........... : ${PCRE2_SUPPORT_VALGRIND}")
   if(PCRE2_DISABLE_PERCENT_ZT)
     message(STATUS "  Use %zu and %td ................... : OFF")
   else()

Makefile.am

@@ -276,7 +276,10 @@ EXTRA_DIST =
 # These files contain additional m4 macros that are used by autoconf.
 
 EXTRA_DIST += \
-  m4/ax_pthread.m4 m4/pcre2_visibility.m4
+  m4/ax_check_vscript.m4 \
+  m4/ax_pthread.m4 \
+  m4/pcre2_visibility.m4 \
+  m4/pcre2_zos.m4
 
 # These files contain maintenance information
 
@@ -891,6 +894,13 @@ pkgconfig_DATA += libpcre2-32.pc
 endif
 
 
+# Symbol version files for use with GNU and Sun ld.
+
+EXTRA_DIST += \
+  src/libpcre2-8.sym src/libpcre2-16.sym src/libpcre2-32.sym \
+  src/libpcre2-posix.sym
+
+
 # gcov/lcov code coverage reporting
 #
 # Coverage reporting targets:
@@ -1001,6 +1011,7 @@ EXTRA_DIST += \
   cmake/FindReadline.cmake \
   cmake/pcre2-config-version.cmake.in \
   cmake/pcre2-config.cmake.in \
+  cmake/PCRE2CheckLinkerFlag.cmake \
   src/config-cmake.h.in \
   CMakeLists.txt
 

README

@@ -169,6 +169,9 @@ library. They are also documented in the pcre2build man page.
   versions of all the relevant libraries are available for linking. See also
   "Shared libraries" below.
 
+  Shared libraries are compiled with symbol versioning enabled on platforms that
+  support this, but this can be disabled by adding --disable-symvers.
+
 . By default, only the 8-bit library is built. If you add --enable-pcre2-16 to
   the "configure" command, the 16-bit library is also built. If you add
   --enable-pcre2-32 to the "configure" command, the 32-bit library is also
@@ -956,6 +959,10 @@ The distribution should contain the files listed below.
   testdata/testoutput*     expected test results
   testdata/grep*           input and output for pcre2grep tests
   testdata/*               other supporting test files
+  src/libpcre2-8.sym       )
+  src/libpcre2-16.sym      ) symbol version scripts for the GNU and Sun linkers
+  src/libpcre2-32.sym      )
+  src/libpcre2-posix.sym   )
 
 (D) Auxiliary files for CMake support
 
@@ -964,6 +971,7 @@ The distribution should contain the files listed below.
   cmake/FindReadline.cmake
   cmake/pcre2-config-version.cmake.in
   cmake/pcre2-config.cmake.in
+  cmake/PCRE2CheckLinkerFlag.cmake
   src/config-cmake.h.in
   CMakeLists.txt
 

cmake/PCRE2CheckLinkerFlag.cmake

@@ -0,0 +1,25 @@
+include(CheckLinkerFlag OPTIONAL)
+
+# This file can be removed once the minimum CMake version is increased to 3.18
+# or higher. Calls to pcre2_check_linker_flag can be changed to the built in
+# check_linker_flag.
+
+if(COMMAND check_linker_flag)
+  macro(pcre2_check_linker_flag)
+    check_linker_flag(${ARGN})
+  endmacro()
+else()
+  # Fallback for versions of CMake older than 3.18.
+
+  include(CheckCCompilerFlag)
+
+  function(pcre2_check_linker_flag lang flag out_var)
+    cmake_policy(PUSH)
+    cmake_policy(SET CMP0056 NEW)
+    set(_CMAKE_EXE_LINKER_FLAGS_SAVE ${CMAKE_EXE_LINKER_FLAGS})
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${flag}")
+    check_c_compiler_flag("" ${out_var})
+    set(CMAKE_EXE_LINKER_FLAGS ${_CMAKE_EXE_LINKER_FLAGS_SAVE})
+    cmake_policy(POP)
+  endfunction()
+endif()