gcc.jam

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        #
        # lib a : a.cpp b ;
        # obj b : b.cpp ;
        # exe c : c.cpp a d ;
        # obj d : d.cpp ;
        #
        # This all is fine, except that 'd' will be compiled with -fPIC even though
        # it is not needed, as 'd' is used only in exe. However, it is hard to
        # detect where a target is going to be used. Alternatively, we can set -fPIC
        # only when main target type is LIB but than 'b' would be compiled without
        # -fPIC which would lead to link errors on x86-64. So, compile everything
        # with -fPIC.
        #
        # Yet another alternative would be to create a propagated <sharedable>
        # feature and set it when building shared libraries, but that would be hard
        # to implement and would increase the target path length even more.
        
        # On Windows, fPIC is default, specifying -fPIC explicitly leads to
        # a warning.
        if $(target) != cygwin && $(target) != windows
        {
            OPTIONS on $(targets) += -fPIC ;
        }        
    }
}

# FIXME: this should not use os.name.
if [ os.name ] != NT && [ os.name ] != OSF && [ os.name ] != HPUX && [ os.name ] != AIX
{
    # OSF does have an option called -soname but it does not seem to work as
    # expected, therefore it has been disabled.
    HAVE_SONAME   = "" ;
    SONAME_OPTION = -h ;
}


toolset.flags gcc.compile USER_OPTIONS <cflags> ;
toolset.flags gcc.compile.c++ USER_OPTIONS <cxxflags> ;
toolset.flags gcc.compile DEFINES <define> ;
toolset.flags gcc.compile INCLUDES <include> ;
toolset.flags gcc.compile.c++ TEMPLATE_DEPTH <c++-template-depth> ;

rule compile.c++.pch ( targets * : sources * : properties * )
{
    setup-fpic $(targets) : $(sources) : $(properties) ;
}

actions compile.c++.pch
{
    "$(CONFIG_COMMAND)" -x c++-header $(OPTIONS) -D$(DEFINES) -I"$(INCLUDES)" -c -o "$(<)" "$(>)"
}

rule compile.c.pch ( targets * : sources * : properties * )
{
    setup-fpic $(targets) : $(sources) : $(properties) ;
}

actions compile.c.pch
{
    "$(CONFIG_COMMAND)" -x c-header $(OPTIONS) -D$(DEFINES) -I"$(INCLUDES)" -c -o "$(<)" "$(>)"
}

rule compile.c++ ( targets * : sources * : properties * )
{
    setup-threading $(targets) : $(sources) : $(properties) ;
    setup-fpic $(targets) : $(sources) : $(properties) ;
    
    # Some extensions are compiled as C++ by default. For others, we need to
    # pass -x c++. We could always pass -x c++ but distcc does not work with it.
    if ! $(>:S) in .cc .cp .cxx .cpp .c++ .C
    {
        LANG on $(<) = "-x c++" ;
    }
    DEPENDS $(<) : [ on $(<) return $(PCH_FILE) ] ;
    
    # Here we want to raise the template-depth parameter value to something
    # higher than the default value of 17. Note that we could do this using the
    # feature.set-default rule but we do not want to set the default value for
    # all toolsets as well.
    #
    # TODO: This 'modified default' has been inherited from some 'older Boost
    # Build implementation' and has most likely been added to make some Boost
    # library parts compile correctly. We should see what exactly prompted this
    # and whether we can get around the problem more locally.
    local template-depth = [ on $(<) return $(TEMPLATE_DEPTH) ] ;
    if ! $(template-depth)
    {
        TEMPLATE_DEPTH on $(<) = 128 ;
    }
}

rule compile.c ( targets * : sources * : properties * )
{
    setup-threading $(targets) : $(sources) : $(properties) ;
    setup-fpic $(targets) : $(sources) : $(properties) ;
    
    # If we use the name g++ then default file suffix -> language mapping does
    # not work. So have to pass -x option. Maybe, we can work around this by
    # allowing the user to specify both C and C++ compiler names.
    #if $(>:S) != .c
    #{
        LANG on $(<) = "-x c" ;
    #}
    DEPENDS $(<) : [ on $(<) return $(PCH_FILE) ] ;
}

actions compile.c++ bind PCH_FILE
{
    "$(CONFIG_COMMAND)" $(LANG) -ftemplate-depth-$(TEMPLATE_DEPTH) $(OPTIONS) $(USER_OPTIONS) -D$(DEFINES) -I"$(PCH_FILE:D)" -I"$(INCLUDES)" -c -o "$(<:W)" "$(>:W)"
}

actions compile.c bind PCH_FILE
{
    "$(CONFIG_COMMAND)" $(LANG) $(OPTIONS) $(USER_OPTIONS) -D$(DEFINES) -I"$(PCH_FILE:D)" -I"$(INCLUDES)" -c -o "$(<)" "$(>)"
}

rule compile.asm
{
    LANG on $(<) = "-x assembler-with-cpp" ;
}

actions compile.asm
{
    "$(CONFIG_COMMAND)" $(LANG) $(OPTIONS) -D$(DEFINES) -I"$(INCLUDES)" -c -o "$(<)" "$(>)"
}

# The class which check that we don't try to use the <runtime-link>static
# property while creating or using shared library, since it's not supported by
# gcc/libc.
class gcc-linking-generator : unix-linking-generator
{
    rule run ( project name ? : property-set : sources + )
    {
        # TODO: Replace this with the use of a target-os property.
        local no-static-link = ;
        if [ modules.peek : UNIX ]
        {
            switch [ modules.peek : JAMUNAME ]
            {
                case * : no-static-link = true ;
            }
        }

        local properties = [ $(property-set).raw ] ;
        local reason ;
        if $(no-static-link) && <runtime-link>static in $(properties)
        {
            if <link>shared in $(properties)
            {
                reason =
                    "On gcc, DLL can't be build with '<runtime-link>static'." ;
            }
            else if [ type.is-derived $(self.target-types[1]) EXE ]
            {
                for local s in $(sources)
                {
                    local type = [ $(s).type ] ;
                    if $(type) &&  [ type.is-derived $(type) SHARED_LIB ]
                    {
                        reason =
                            "On gcc, using DLLS together with the"
                            "<runtime-link>static options is not possible " ;
                    }
                }
            }
        }
        if $(reason)
        {
            ECHO warning:
                $(reason) ;
            ECHO warning:
                "It is suggested to use '<runtime-link>static' together"
                "with '<link>static'." ;
            return ;
        }
        else
        {
            local generated-targets = [ unix-linking-generator.run $(project)
                $(name) : $(property-set) : $(sources) ] ;
            return $(generated-targets) ;
        }
    }
}

.IMPLIB-COMMAND = ;
if [ os.on-windows ]
{
    .IMPLIB-COMMAND = "-Wl,--out-implib," ;
    generators.register
        [ new gcc-linking-generator gcc.link
            : OBJ SEARCHED_LIB STATIC_LIB IMPORT_LIB
            : EXE
            : <toolset>gcc ] ;
    generators.register
        [ new gcc-linking-generator gcc.link.dll
            : OBJ SEARCHED_LIB STATIC_LIB IMPORT_LIB
            : IMPORT_LIB SHARED_LIB
            : <toolset>gcc ] ;
}
else
{
    generators.register
        [ new gcc-linking-generator gcc.link
            : LIB OBJ
            : EXE
            : <toolset>gcc ] ;
    generators.register
        [ new gcc-linking-generator gcc.link.dll
            : LIB OBJ
            : SHARED_LIB
            : <toolset>gcc ] ;
}

# Declare flags for linking.
# First, the common flags.
toolset.flags gcc.link OPTIONS <debug-symbols>on : -g ;
toolset.flags gcc.link OPTIONS <profiling>on : -pg ;
toolset.flags gcc.link USER_OPTIONS <linkflags> ;
toolset.flags gcc.link LINKPATH <library-path> ;
toolset.flags gcc.link FINDLIBS-ST <find-static-library> ;
toolset.flags gcc.link FINDLIBS-SA <find-shared-library> ;
toolset.flags gcc.link LIBRARIES <library-file> ;

# For <runtime-link>static we made sure there are no dynamic libraries in the
# link. On HP-UX not all system libraries exist as archived libraries (for
# example, there is no libunwind.a), so, on this platform, the -static option
# cannot be specified.
if [ os.name ] != HPUX
{
    toolset.flags gcc.link OPTIONS <runtime-link>static : -static ;
}

# Now, the vendor specific flags.
# The parameter linker can be either aix, darwin, gnu, hpux, osf or sun.
rule init-link-flags ( toolset linker condition )
{
    switch $(linker)
    {
    case aix :
        {
        #
        # On AIX we *have* to use the native linker.
        #
        # Using -brtl, the AIX linker will look for libraries with both the .a
        # and .so extensions, such as libfoo.a and libfoo.so. Without -brtl, the
        # AIX linker looks only for libfoo.a. Note that libfoo.a is an archived
        # file that may contain shared objects and is different from static libs
        # as on Linux.
        #
        # The -bnoipath strips the prepending (relative) path of libraries from
        # the loader section in the target library or executable. Hence, during
        # load-time LIBPATH (identical to LD_LIBRARY_PATH) or a hard-coded
        # -blibpath (*similar* to -lrpath/-lrpath-link) is searched. Without
        # this option, the prepending (relative) path + library name is
        # hard-coded in the loader section, causing *only* this path to be
        # searched during load-time. Note that the AIX linker does not have an
        # -soname equivalent, this is as close as it gets.
        #
        # The above options are definately for AIX 5.x, and most likely also for
        # AIX 4.x and AIX 6.x. For details about the AIX linker see:
        # http://download.boulder.ibm.com/ibmdl/pub/software/dw/aix/es-aix_ll.pdf
        #

        toolset.flags $(toolset).link OPTIONS : -Wl,-brtl -Wl,-bnoipath
            : unchecked ;
        }

    case darwin :
        {
        # On Darwin, the -s option to ld does not work unless we pass -static,
        # and passing -static unconditionally is a bad idea. So, don't pass -s.
        # at all, darwin.jam will use separate 'strip' invocation.
        toolset.flags $(toolset).link RPATH $(condition) : <dll-path> : unchecked ;
        toolset.flags $(toolset).link RPATH_LINK $(condition) : <xdll-path> : unchecked ;
        }

    case gnu :
        {
        # Strip the binary when no debugging is needed. We use --strip-all flag
        # as opposed to -s since icc (intel's compiler) is generally
        # option-compatible with and inherits from the gcc toolset, but does not
        # support -s.
        toolset.flags $(toolset).link OPTIONS     $(condition)/<debug-symbols>off : -Wl,--strip-all   : unchecked ;
        toolset.flags $(toolset).link RPATH       $(condition)                    : <dll-path>        : unchecked ;
        toolset.flags $(toolset).link RPATH_LINK  $(condition)                    : <xdll-path>       : unchecked ;
        toolset.flags $(toolset).link START-GROUP $(condition)                    : -Wl,--start-group : unchecked ;
        toolset.flags $(toolset).link END-GROUP   $(condition)                    : -Wl,--end-group   : unchecked ;

        # gnu ld has the ability to change the search behaviour for libraries
        # referenced by -l switch. These modifiers are -Bstatic and -Bdynamic
        # and change search for -l switches that follow them. The following list
        # shows the tried variants.
        # The search stops at the first variant that has a match.
        # *nix: -Bstatic -lxxx
        #    libxxx.a
        #
        # *nix: -Bdynamic -lxxx
        #    libxxx.so
        #    libxxx.a
        #
        # windows (mingw,cygwin) -Bstatic -lxxx
        #    libxxx.a
        #    xxx.lib
        #
        # windows (mingw,cygwin) -Bdynamic -lxxx
        #    libxxx.dll.a
        #    xxx.dll.a
        #    libxxx.a
        #    xxx.lib
        #    cygxxx.dll (*)
        #    libxxx.dll
        #    xxx.dll
        #    libxxx.a
        #
        # (*) This is for cygwin
        # Please note that -Bstatic and -Bdynamic are not a guarantee that a
        # static or dynamic lib indeed gets linked in. The switches only change
        # search patterns!