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From: Jonathan Wakely <jwakely@redhat.com>
To: "Arsen Arsenović" <arsen@aarsen.me>
Cc: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org
Subject: Re: [PATCH] libstdc++: Enable building libstdc++.{a,so} when !HOSTED
Date: Mon, 6 Feb 2023 14:24:52 +0000	[thread overview]
Message-ID: <CACb0b4=4aObWvQr2fdO7K_NUfi-oaoSOE=RGR0vZ1hw882D27A@mail.gmail.com> (raw)
In-Reply-To: <20221020154948.2511787-1-arsen@aarsen.me>

This is pushed to trunk now.

On Thu, 20 Oct 2022 at 16:53, Arsen Arsenović via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> This enables us to provide symbols for placeholders and numeric limits,
> and allows users to mess about with linker flags less.
>
> libstdc++-v3/ChangeLog:
>
>         * Makefile.am [!_GLIBCXX_HOSTED]: Enable src/ subdirectory.
>         * Makefile.in: Regenerate.
>         * src/Makefile.am [!_GLIBCXX_HOSTED]: Omit compatibility files.
>         There's no history to be compatible with.
>         * src/c++11/Makefile.am [!_GLIBCXX_HOSTED]: Omit hosted-only
>         source files from the build.
>         * src/c++17/Makefile.am [!_GLIBCXX_HOSTED]: Likewise.
>         * src/c++20/Makefile.am [!_GLIBCXX_HOSTED]: Likewise.
>         * src/c++98/Makefile.am [!_GLIBCXX_HOSTED]: Likewise.
>         * src/Makefile.in: Regenerate.
>         * src/c++11/Makefile.in: Regenerate.
>         * src/c++17/Makefile.in: Regenerate.
>         * src/c++20/Makefile.in: Regenerate.
>         * src/c++98/Makefile.in: Regenerate.
> ---
> Afternoon,
>
> With these changes, when we aren't hosted, we get a libstdc++ library that
> contains only library facilities available in freestanding (i.e. placeholders
> and limits.cc).  This is, AFAICT, the only code in libstdc++.{a,so} that can
> (and should) be available in freestanding.
>
> As an implementation note, this could be a little bit faster (at
> build/configure time), though not necessarily nicer, by having
> src/Makefile.am not try to build convenience libraries for versions of
> C++ that provide nothing.  I opted not to do this since it'd make
> src/Makefile.am even more complex, and make future changes harder to implement.
> libstdc++ also isn't that slow to build, anyway.
>
> Tested on i686-elf.
>
> Have a good day!
>
>  libstdc++-v3/Makefile.am           |  4 ++--
>  libstdc++-v3/Makefile.in           |  4 ++--
>  libstdc++-v3/src/Makefile.am       |  6 +++++
>  libstdc++-v3/src/Makefile.in       |  8 +++++--
>  libstdc++-v3/src/c++11/Makefile.am | 16 ++++++++++---
>  libstdc++-v3/src/c++11/Makefile.in | 37 +++++++++++++++++++-----------
>  libstdc++-v3/src/c++17/Makefile.am |  4 ++++
>  libstdc++-v3/src/c++17/Makefile.in |  6 +++--
>  libstdc++-v3/src/c++20/Makefile.am |  4 ++++
>  libstdc++-v3/src/c++20/Makefile.in |  6 +++--
>  libstdc++-v3/src/c++98/Makefile.am |  4 ++++
>  libstdc++-v3/src/c++98/Makefile.in |  6 +++--
>  12 files changed, 77 insertions(+), 28 deletions(-)
>
> diff --git a/libstdc++-v3/Makefile.am b/libstdc++-v3/Makefile.am
> index 0d147ad3ffe..d7f2b6e76a5 100644
> --- a/libstdc++-v3/Makefile.am
> +++ b/libstdc++-v3/Makefile.am
> @@ -24,11 +24,11 @@ include $(top_srcdir)/fragment.am
>
>  if GLIBCXX_HOSTED
>  ## Note that python must come after src.
> -  hosted_source = src doc po testsuite python
> +  hosted_source = doc po testsuite python
>  endif
>
>  ## Keep this list sync'd with acinclude.m4:GLIBCXX_CONFIGURE.
> -SUBDIRS = include libsupc++ $(hosted_source)
> +SUBDIRS = include libsupc++ src $(hosted_source)
>
>  ACLOCAL_AMFLAGS = -I . -I .. -I ../config
>
> diff --git a/libstdc++-v3/src/Makefile.am b/libstdc++-v3/src/Makefile.am
> index b83c222d51d..4eb78e76297 100644
> --- a/libstdc++-v3/src/Makefile.am
> +++ b/libstdc++-v3/src/Makefile.am
> @@ -121,7 +121,13 @@ cxx11_sources = \
>         ${cxx0x_compat_sources} \
>         ${ldbl_alt128_compat_sources}
>
> +if GLIBCXX_HOSTED
>  libstdc___la_SOURCES = $(cxx98_sources) $(cxx11_sources)
> +else
> +# When freestanding, there's currently no compatibility to preserve.  Should
> +# that change, any compatibility sources can be added here.
> +libstdc___la_SOURCES =
> +endif
>
>  libstdc___la_LIBADD = \
>         $(GLIBCXX_LIBS) \
> diff --git a/libstdc++-v3/src/c++11/Makefile.am b/libstdc++-v3/src/c++11/Makefile.am
> index ecd46aafc01..72f05100c98 100644
> --- a/libstdc++-v3/src/c++11/Makefile.am
> +++ b/libstdc++-v3/src/c++11/Makefile.am
> @@ -51,6 +51,10 @@ else
>  cxx11_abi_sources =
>  endif
>
> +sources_freestanding = \
> +       limits.cc \
> +       placeholders.cc
> +
>  sources = \
>         chrono.cc \
>         codecvt.cc \
> @@ -66,9 +70,7 @@ sources = \
>         hashtable_c++0x.cc \
>         ios.cc \
>         ios_errcat.cc \
> -       limits.cc \
>         mutex.cc \
> -       placeholders.cc \
>         random.cc \
>         regex.cc  \
>         shared_ptr.cc \
> @@ -118,7 +120,15 @@ endif
>
>  vpath % $(top_srcdir)/src/c++11
>
> -libc__11convenience_la_SOURCES = $(sources)  $(inst_sources)
> +if !GLIBCXX_HOSTED
> +libc__11convenience_la_SOURCES = $(sources_freestanding)
> +else
> +libc__11convenience_la_SOURCES = \
> +       $(sources_freestanding) \
> +       $(sources) \
> +       $(inst_sources)
> +endif
> +
>
>  # Use special rules for the hashtable.cc file so that all
>  # the generated template functions are also instantiated.
> diff --git a/libstdc++-v3/src/c++17/Makefile.am b/libstdc++-v3/src/c++17/Makefile.am
> index 3d53f652fac..72095f5b087 100644
> --- a/libstdc++-v3/src/c++17/Makefile.am
> +++ b/libstdc++-v3/src/c++17/Makefile.am
> @@ -60,7 +60,11 @@ sources = \
>
>  vpath % $(top_srcdir)/src/c++17
>
> +if GLIBCXX_HOSTED
>  libc__17convenience_la_SOURCES = $(sources)  $(inst_sources)
> +else
> +libc__17convenience_la_SOURCES =
> +endif
>
>  if GLIBCXX_LDBL_ALT128_COMPAT
>  floating_from_chars.lo: floating_from_chars.cc
> diff --git a/libstdc++-v3/src/c++20/Makefile.am b/libstdc++-v3/src/c++20/Makefile.am
> index d4c1e26e40e..5c937f7e804 100644
> --- a/libstdc++-v3/src/c++20/Makefile.am
> +++ b/libstdc++-v3/src/c++20/Makefile.am
> @@ -40,7 +40,11 @@ sources =
>
>  vpath % $(top_srcdir)/src/c++20
>
> +if GLIBCXX_HOSTED
>  libc__20convenience_la_SOURCES = $(sources)  $(inst_sources)
> +else
> +libc__20convenience_la_SOURCES =
> +endif
>
>  # AM_CXXFLAGS needs to be in each subdirectory so that it can be
>  # modified in a per-library or per-sub-library way.  Need to manually
> diff --git a/libstdc++-v3/src/c++98/Makefile.am b/libstdc++-v3/src/c++98/Makefile.am
> index b96588bd95c..f7134d80027 100644
> --- a/libstdc++-v3/src/c++98/Makefile.am
> +++ b/libstdc++-v3/src/c++98/Makefile.am
> @@ -148,7 +148,11 @@ sources = \
>
>  vpath % $(top_srcdir)/src/c++98
>
> +if GLIBCXX_HOSTED
>  libc__98convenience_la_SOURCES = $(sources)
> +else
> +libc__98convenience_la_SOURCES =
> +endif
>
>  # Use special rules to compile with -fimplicit-templates.
>  c++locale.lo: c++locale.cc
>  # Use special rules for the deprecated source files so that they find
> --
> 2.38.1
>


      parent reply	other threads:[~2023-02-06 14:25 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-20 15:49 Arsen Arsenović
2022-11-14 18:34 ` Ping: " Arsen Arsenović
2022-11-15 15:58 ` Jonathan Wakely
2022-11-15 18:03   ` Arsen Arsenović
2023-02-06 14:24 ` Jonathan Wakely [this message]

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