windows: integrate visibility attributes without conflicts

When using a DLL in Windows, the function declarations (and definitions)
that are public are decorated with attributes but those declarations would
conflict with the ones that are selected when the compiler supports the
visibility feature.

Define instead a new macro that would be added to the corresponding
macros independently and while at it allow setting visibility with cmake.

Author: carenas

.gitignore

@@ -40,15 +40,19 @@ missing
 pcre2-config
 pcre2_dftables
 pcre2_jit_test
+pcre2_jit_test.exe
 pcre2_jit_test.log
 pcre2_jit_test.trs
 pcre2posix_test
+pcre2posix_test.exe
 pcre2posix_test.log
 pcre2posix_test.trs
 pcre2demo
 pcre2fuzzcheck
 pcre2grep
+pcre2grep.exe
 pcre2test
+pcre2test.exe
 test-driver
 test-suite.log
 test3input

CMakeLists.txt

@@ -102,13 +102,15 @@
 # 2022-12-10 PH added support for pcre2posix_test
 # 2023-01-15 Carlo added C99 as the minimum required
 
-# Increased minimum to 2.8.5 to support GNUInstallDirs.
-# Increased minimum to 3.1 to support imported targets.
-CMAKE_MINIMUM_REQUIRED(VERSION 3.1)
+# Increased minimum to 3.3 to support visibility.
+CMAKE_MINIMUM_REQUIRED(VERSION 3.3)
 PROJECT(PCRE2 C)
 set(CMAKE_C_STANDARD 99)
 set(CMAKE_C_STANDARD_REQUIRED TRUE)
 
+set(CMAKE_C_VISIBILITY_PRESET hidden)
+cmake_policy(SET CMP0063 NEW)
+
 # Set policy CMP0026 to avoid warnings for the use of LOCATION in
 # GET_TARGET_PROPERTY. This should no longer be required.
 # CMAKE_POLICY(SET CMP0026 OLD)
@@ -156,7 +158,7 @@ CHECK_SYMBOL_EXISTS(strerror      "string.h"   HAVE_STRERROR)
 CHECK_C_SOURCE_COMPILES(
   "#include <stdlib.h>
    #include <limits.h>
-   int main(int c, char *v[]) { char buf[PATH_MAX]; realpath(v[1], buf); return 0; }"
+   int main(int c, char *v[]) { char buf[PATH_MAX]; realpath(v[c], buf); return 0; }"
   HAVE_REALPATH
 )
 
@@ -165,14 +167,28 @@ set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Werror")
 
 CHECK_C_SOURCE_COMPILES(
   "#include <stddef.h>
-   int main() { int a,b; size_t m; __builtin_mul_overflow(a,b,&m); return 0; }"
+   int main(void) { int a,b; size_t m; __builtin_mul_overflow(a,b,&m); return 0; }"
   HAVE_BUILTIN_MUL_OVERFLOW
 )
 
 CHECK_C_SOURCE_COMPILES(
-  "int main() { char buf[128] __attribute__((uninitialized)); (void)buf; return 0; }"
+  "int main(void) { char buf[128] __attribute__((uninitialized)); (void)buf; return 0; }"
   HAVE_ATTRIBUTE_UNINITIALIZED
 )
+
+CHECK_C_SOURCE_COMPILES([=[
+  extern __attribute__ ((visibility ("default"))) int f(void);
+  int main(void) { return f(); }
+  int f(void) { return 42; }
+  ]=] 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 whether Intel CET is enabled, and if so, adjust compiler flags. This
@@ -191,8 +207,6 @@ IF (INTEL_CET_ENABLED)
   SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mshstk")
 ENDIF(INTEL_CET_ENABLED)
 
-
-
 # User-configurable options
 #
 # Note: CMakeSetup displays these in alphabetical order, regardless of
@@ -729,7 +743,6 @@ IF(PCRE2_BUILD_PCRE2_8)
       VERSION ${LIBPCRE2_POSIX_VERSION}
       SOVERSION ${LIBPCRE2_POSIX_SOVERSION})
     TARGET_LINK_LIBRARIES(pcre2-posix-static pcre2-8-static)
-    TARGET_COMPILE_DEFINITIONS(pcre2-posix-static PUBLIC PCRE2_STATIC)
     TARGET_INCLUDE_DIRECTORIES(pcre2-posix-static PUBLIC ${PROJECT_BINARY_DIR})
     SET(targets ${targets} pcre2-posix-static)
 
@@ -759,6 +772,7 @@ IF(PCRE2_BUILD_PCRE2_8)
         TARGET_LINK_LIBRARIES(pcre2-8-shared Threads::Threads)
     ENDIF(REQUIRE_PTHREAD)
     SET(targets ${targets} pcre2-8-shared)
+
     ADD_LIBRARY(pcre2-posix-shared SHARED ${PCRE2POSIX_HEADERS} ${PCRE2POSIX_SOURCES})
     TARGET_INCLUDE_DIRECTORIES(pcre2-posix-shared PUBLIC ${PROJECT_BINARY_DIR})
     SET_TARGET_PROPERTIES(pcre2-posix-shared PROPERTIES
@@ -768,6 +782,7 @@ IF(PCRE2_BUILD_PCRE2_8)
       VERSION ${LIBPCRE2_POSIX_VERSION}
       SOVERSION ${LIBPCRE2_POSIX_SOVERSION}
       OUTPUT_NAME pcre2-posix)
+    TARGET_COMPILE_DEFINITIONS(pcre2-posix-shared PUBLIC PCRE2POSIX_SHARED)
     TARGET_LINK_LIBRARIES(pcre2-posix-shared pcre2-8-shared)
     SET(targets ${targets} pcre2-posix-shared)
     SET(dll_pdb_files ${PROJECT_BINARY_DIR}/pcre2-8.pdb ${dll_pdb_files})

Makefile.am

@@ -292,8 +292,7 @@ src/pcre2.h.generic: src/pcre2.h.in configure.ac
 # config.status out of the way while doing the default configuration. The
 # resulting config.h is munged by perl to put #ifdefs round any #defines for
 # macros with values, and to #undef all boolean macros such as HAVE_xxx and
-# SUPPORT_xxx. We also get rid of any gcc-specific visibility settings. Make
-# sure that PCRE2_EXP_DEFN is unset (in case it has visibility settings).
+# SUPPORT_xxx. We also get rid of any gcc-specific visibility settings.
 
 src/config.h.generic: configure.ac
 	rm -rf $@ _generic
@@ -304,9 +303,7 @@ src/config.h.generic: configure.ac
 	test -f _generic/src/config.h
 	perl -n \
 	  -e 'BEGIN{$$blank=0;}' \
-	  -e 'if(/PCRE2_EXP_DEFN/){print"/* #undef PCRE2_EXP_DEFN */\n";$$blank=0;next;}' \
-	  -e 'if(/to make a symbol visible/){next;}' \
-	  -e 'if(/__attribute__ \(\(visibility/){next;}' \
+	  -e 'if(/(.+?)\s*__attribute__ \(\(visibility/){print"$$1\n";$$blank=0;next;}' \
 	  -e 'if(/LT_OBJDIR/){print"/* This is ignored unless you are using libtool. */\n";}' \
 	  -e 'if(/^#define\s((?:HAVE|SUPPORT|STDC)_\w+)/){print"/* #undef $$1 */\n";$$blank=0;next;}' \
 	  -e 'if(/^#define\s(?!PACKAGE|VERSION)(\w+)/){print"#ifndef $$1\n$$_#endif\n";$$blank=0;next;}' \
@@ -518,7 +515,7 @@ if WITH_PCRE2_8
 lib_LTLIBRARIES += libpcre2-posix.la
 libpcre2_posix_la_SOURCES = src/pcre2posix.c
 libpcre2_posix_la_CFLAGS = \
-  -DPCRE2_CODE_UNIT_WIDTH=8 \
+  -DPCRE2_CODE_UNIT_WIDTH=8 @PCRE2POSIX_CFLAG@ \
   $(VISIBILITY_CFLAGS) $(AM_CFLAGS)
 libpcre2_posix_la_LDFLAGS = $(EXTRA_LIBPCRE2_POSIX_LDFLAGS)
 libpcre2_posix_la_LIBADD = libpcre2-8.la
@@ -570,7 +567,7 @@ if WITH_PCRE2_8
 TESTS += pcre2posix_test
 noinst_PROGRAMS += pcre2posix_test
 pcre2posix_test_SOURCES = src/pcre2posix_test.c
-pcre2posix_test_CFLAGS = $(AM_CFLAGS)
+pcre2posix_test_CFLAGS = $(AM_CFLAGS) @PCRE2POSIX_CFLAG@
 pcre2posix_test_LDADD = libpcre2-posix.la libpcre2-8.la
 endif # WITH_PCRE2_8
 

NON-AUTOTOOLS-BUILD

@@ -159,7 +159,8 @@ example.
  (7) If you want to build the POSIX wrapper functions (which apply only to the
      8-bit library), ensure that you have the src/pcre2posix.h file and then
      compile src/pcre2posix.c. Link the result (on its own) as the pcre2posix
-     library.
+     library. If targeting a DLL in Windows, make sure to include
+     -DPCRE2POSIX_SHARED with your compiler flags.
 
  (8) The pcre2test program can be linked with any combination of the 8-bit,
      16-bit and 32-bit libraries (depending on what you specfied in

config-cmake.h.in

@@ -3,7 +3,6 @@
 #cmakedefine HAVE_BUILTIN_MUL_OVERFLOW 1
 #cmakedefine HAVE_ATTRIBUTE_UNINITIALIZED 1
 #cmakedefine HAVE_DIRENT_H 1
-#cmakedefine HAVE_STRERROR 1
 #cmakedefine HAVE_SYS_STAT_H 1
 #cmakedefine HAVE_SYS_TYPES_H 1
 #cmakedefine HAVE_UNISTD_H 1
@@ -40,6 +39,7 @@
 #cmakedefine HEAP_MATCH_RECURSE 1
 #cmakedefine NEVER_BACKSLASH_C 1
 
+#define PCRE2_EXPORT		@PCRE2_EXPORT@
 #define LINK_SIZE		@PCRE2_LINK_SIZE@
 #define HEAP_LIMIT              @PCRE2_HEAP_LIMIT@
 #define MATCH_LIMIT		@PCRE2_MATCH_LIMIT@

configure.ac

@@ -640,6 +640,12 @@ if test "x$enable_shared" = "xno" ; then
 fi
 AC_SUBST(PCRE2_STATIC_CFLAG)
 
+PCRE2POSIX_CFLAG=""
+if test "x$enable_shared" = "xyes" ; then
+  PCRE2POSIX_CFLAG="-DPCRE2POSIX_SHARED"
+fi
+AC_SUBST(PCRE2POSIX_CFLAG)
+
 # Here is where PCRE2-specific defines are handled
 
 if test "$enable_pcre2_8" = "yes"; then
@@ -812,7 +818,7 @@ AC_DEFINE_UNQUOTED([MATCH_LIMIT], [$with_match_limit], [
   matching attempt. The value is also used to limit a loop counter in
   pcre2_dfa_match(). There is a runtime interface for setting a different
   limit. The limit exists in order to catch runaway regular expressions that
-  take for ever to determine that they do not match. The default is set very
+  take forever to determine that they do not match. The default is set very
   large so that it does not accidentally catch legitimate cases.])
 
 # --with-match-limit-recursion is an obsolete synonym for --with-match-limit-depth
@@ -862,8 +868,9 @@ AH_VERBATIM([PCRE2_EXP_DEFN], [
    Win32, and it needs some magic to be inserted before the definition
    of a function that is exported by the library, define this macro to
    contain the relevant magic. If you do not define this macro, a suitable
-    __declspec value is used for Windows systems; in other environments
-   "extern" is used for a C compiler and "extern C" for a C++ compiler.
+   __declspec value is used for Windows systems; in other environments
+   a compiler relevant "extern" is used with any "visibility" related
+   attributes from PCRE2_EXPORT included.
    This macro apears at the start of every exported function that is part
    of the external API. It does not appear on functions that are "external"
    in the C sense, but which are internal to the library. */

doc/pcre2posix.3

@@ -1,4 +1,4 @@
-.TH PCRE2POSIX 3 "26 April 2021" "PCRE2 10.37"
+.TH PCRE2POSIX 3 "13 May 2023" "PCRE2 10.43"
 .SH NAME
 PCRE2 - Perl-compatible regular expressions (revised API)
 .SH "SYNOPSIS"
@@ -44,7 +44,12 @@ can be accessed by adding \fB-lpcre2-posix\fP to the command for linking an
 application. Because the POSIX functions call the native ones, it is also
 necessary to add \fB-lpcre2-8\fP.
 .P
-Although they were not defined as protypes in \fBpcre2posix.h\fP, releases
+On Windows systems, if you are linking to a DLL version of the library, it is
+recommended that \fBPCRE2POSIX_SHARED\fP is defined before including the
+\fBpcre2posix.h\fP header, as it will allow for a more efficient way to
+invoke the functions by adding the \fB__declspec(dllimport)\fP decorator.
+.P
+Although they were not defined as prototypes in \fBpcre2posix.h\fP, releases
 10.33 to 10.36 of the library contained functions with the POSIX names
 \fBregcomp()\fP etc. These simply passed their arguments to the PCRE2
 functions. These functions were provided for backwards compatibility with

libpcre2-posix.pc.in

@@ -9,5 +9,5 @@ Name: libpcre2-posix
 Description: Posix compatible interface to libpcre2-8
 Version: @PACKAGE_VERSION@
 Libs: -L${libdir} -lpcre2-posix@LIB_POSTFIX@
-Cflags: -I${includedir} @PCRE2_STATIC_CFLAG@
+Cflags: -I${includedir} @PCRE2POSIX_CFLAG@
 Requires.private: libpcre2-8

m4/pcre2_visibility.m4

@@ -73,10 +73,9 @@ AC_DEFUN([PCRE2_VISIBILITY],
       VISIBILITY_CFLAGS="-fvisibility=hidden"
       VISIBILITY_CXXFLAGS="-fvisibility=hidden -fvisibility-inlines-hidden"
       HAVE_VISIBILITY=1
-      AC_DEFINE(PCRE2_EXP_DECL, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
-      AC_DEFINE(PCRE2_EXP_DEFN, [__attribute__ ((visibility ("default")))], [to make a symbol visible])
-      AC_DEFINE(PCRE2POSIX_EXP_DECL, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
-      AC_DEFINE(PCRE2POSIX_EXP_DEFN, [extern __attribute__ ((visibility ("default")))], [to make a symbol visible])
+      AC_DEFINE(PCRE2_EXPORT, [__attribute__ ((visibility ("default")))], [to make a symbol visible])
+    else
+      AC_DEFINE(PCRE2_EXPORT, [], [to make a symbol visible])
     fi
   fi
   AC_SUBST([VISIBILITY_CFLAGS])

src/config.h.generic

@@ -184,7 +184,7 @@ sure both macros are undefined; an emulation function will then be used. */
    matching attempt. The value is also used to limit a loop counter in
    pcre2_dfa_match(). There is a runtime interface for setting a different
    limit. The limit exists in order to catch runaway regular expressions that
-   take for ever to determine that they do not match. The default is set very
+   take forever to determine that they do not match. The default is set very
    large so that it does not accidentally catch legitimate cases. */
 #ifndef MATCH_LIMIT
 #define MATCH_LIMIT 10000000
@@ -239,7 +239,7 @@ sure both macros are undefined; an emulation function will then be used. */
 #define PACKAGE_NAME "PCRE2"
 
 /* Define to the full name and version of this package. */
-#define PACKAGE_STRING "PCRE2 10.42"
+#define PACKAGE_STRING "PCRE2 10.43-DEV"
 
 /* Define to the one symbol short name of this package. */
 #define PACKAGE_TARNAME "pcre2"
@@ -248,7 +248,7 @@ sure both macros are undefined; an emulation function will then be used. */
 #define PACKAGE_URL ""
 
 /* Define to the version of this package. */
-#define PACKAGE_VERSION "10.42"
+#define PACKAGE_VERSION "10.43-DEV"
 
 /* The value of PARENS_NEST_LIMIT specifies the maximum depth of nested
    parentheses (of any kind) in a pattern. This limits the amount of system
@@ -278,12 +278,16 @@ sure both macros are undefined; an emulation function will then be used. */
 /* Define to any value to include debugging code. */
 /* #undef PCRE2_DEBUG */
 
+/* to make a symbol visible */
+#define PCRE2_EXPORT
+
 /* If you are compiling for a system other than a Unix-like system or
    Win32, and it needs some magic to be inserted before the definition
    of a function that is exported by the library, define this macro to
    contain the relevant magic. If you do not define this macro, a suitable
-    __declspec value is used for Windows systems; in other environments
-   "extern" is used for a C compiler and "extern C" for a C++ compiler.
+   __declspec value is used for Windows systems; in other environments
+   a compiler relevant "extern" is used with any "visibility" related
+   attributes from PCRE2_EXPORT included.
    This macro apears at the start of every exported function that is part
    of the external API. It does not appear on functions that are "external"
    in the C sense, but which are internal to the library. */
@@ -441,7 +445,7 @@ sure both macros are undefined; an emulation function will then be used. */
 #endif
 
 /* Version number of package */
-#define VERSION "10.42"
+#define VERSION "10.43-DEV"
 
 /* Number of bits in a file offset, on hosts where this is settable. */
 /* #undef _FILE_OFFSET_BITS */

src/config.h.in

@@ -177,7 +177,7 @@ sure both macros are undefined; an emulation function will then be used. */
    matching attempt. The value is also used to limit a loop counter in
    pcre2_dfa_match(). There is a runtime interface for setting a different
    limit. The limit exists in order to catch runaway regular expressions that
-   take for ever to determine that they do not match. The default is set very
+   take forever to determine that they do not match. The default is set very
    large so that it does not accidentally catch legitimate cases. */
 #undef MATCH_LIMIT
 
@@ -252,25 +252,20 @@ sure both macros are undefined; an emulation function will then be used. */
    allows for the buffering of "before" and "after" lines. */
 #undef PCRE2GREP_MAX_BUFSIZE
 
-/* to make a symbol visible */
-#undef PCRE2POSIX_EXP_DECL
-
-/* to make a symbol visible */
-#undef PCRE2POSIX_EXP_DEFN
-
 /* Define to any value to include debugging code. */
 #undef PCRE2_DEBUG
 
 /* to make a symbol visible */
-#undef PCRE2_EXP_DECL
+#undef PCRE2_EXPORT
 
 
 /* If you are compiling for a system other than a Unix-like system or
    Win32, and it needs some magic to be inserted before the definition
    of a function that is exported by the library, define this macro to
    contain the relevant magic. If you do not define this macro, a suitable
-    __declspec value is used for Windows systems; in other environments
-   "extern" is used for a C compiler and "extern C" for a C++ compiler.
+   __declspec value is used for Windows systems; in other environments
+   a compiler relevant "extern" is used with any "visibility" related
+   attributes from PCRE2_EXPORT included.
    This macro apears at the start of every exported function that is part
    of the external API. It does not appear on functions that are "external"
    in the C sense, but which are internal to the library. */

src/pcre2_internal.h

@@ -119,20 +119,20 @@ only if it is not already set. */
 #ifndef PCRE2_EXP_DECL
 #  ifdef _WIN32
 #    ifndef PCRE2_STATIC
-#      define PCRE2_EXP_DECL       extern __declspec(dllexport)
-#      define PCRE2_EXP_DEFN       __declspec(dllexport)
+#      define PCRE2_EXP_DECL		extern __declspec(dllexport)
+#      define PCRE2_EXP_DEFN		__declspec(dllexport)
 #    else
-#      define PCRE2_EXP_DECL       extern
+#      define PCRE2_EXP_DECL		extern PCRE2_EXPORT
 #      define PCRE2_EXP_DEFN
 #    endif
 #  else
 #    ifdef __cplusplus
-#      define PCRE2_EXP_DECL       extern "C"
+#      define PCRE2_EXP_DECL		extern "C" PCRE2_EXPORT
 #    else
-#      define PCRE2_EXP_DECL       extern
+#      define PCRE2_EXP_DECL		extern PCRE2_EXPORT
 #    endif
 #    ifndef PCRE2_EXP_DEFN
-#      define PCRE2_EXP_DEFN       PCRE2_EXP_DECL
+#      define PCRE2_EXP_DEFN		PCRE2_EXP_DECL
 #    endif
 #  endif
 #endif