Re: [PATCH] Support static linking against LLVM

Andres, Tom, I found your names in the git history for JIT and LLVM.
Any chance one of you could take a look at the patch?

-mj

On Thu, Aug 10, 2023 at 2:45 PM Marcelo Juchem <juchem(at)gmail(dot)com> wrote:

> By default, PostgreSQL doesn't explicitly choose whether to link
> statically or dynamically against LLVM when LLVM JIT is enabled (e.g.:
> `./configure --with-llvm`).
>
> `llvm-config` will choose to dynamically link by default.
>
> In order to statically link, one must pass `--link-static` to
> `llvm-config` when listing linker flags (`--ldflags`) and libraries
> (`--libs`).
>
> This patch enables custom flags to be passed to `llvm-config` linker
> related invocations through the environment variable
> `LLVM_CONFIG_LINK_ARGS`.
>
> To statically link against LLVM it suffices, then, to call `configure`
> with environment variable `LLVM_CONFIG_LINK_ARGS=--link-static`.
> ---
> config/llvm.m4 | 5 +++--
> configure | 6 ++++--
> 2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/config/llvm.m4 b/config/llvm.m4
> index 3a75cd8b4d..712bd3de6c 100644
> --- a/config/llvm.m4
> +++ b/config/llvm.m4
> @@ -13,6 +13,7 @@ AC_DEFUN([PGAC_LLVM_SUPPORT],
> AC_REQUIRE([AC_PROG_AWK])
>
> AC_ARG_VAR(LLVM_CONFIG, [path to llvm-config command])
> + AC_ARG_VAR(LLVM_CONFIG_LINK_ARGS, [extra arguments for llvm-config
> linker related flags])
> PGAC_PATH_PROGS(LLVM_CONFIG, llvm-config llvm-config-7 llvm-config-6.0
> llvm-config-5.0 llvm-config-4.0 llvm-config-3.9)
>
> # no point continuing if llvm wasn't found
> @@ -52,7 +53,7 @@ AC_DEFUN([PGAC_LLVM_SUPPORT],
> esac
> done
>
> - for pgac_option in `$LLVM_CONFIG --ldflags`; do
> + for pgac_option in `$LLVM_CONFIG --ldflags $LLVM_CONFIG_LINK_ARGS`; do
> case $pgac_option in
> -L*) LDFLAGS="$LDFLAGS $pgac_option";;
> esac
> @@ -84,7 +85,7 @@ AC_DEFUN([PGAC_LLVM_SUPPORT],
> # And then get the libraries that need to be linked in for the
> # selected components. They're large libraries, we only want to
> # link them into the LLVM using shared library.
> - for pgac_option in `$LLVM_CONFIG --libs --system-libs
> $pgac_components`; do
> + for pgac_option in `$LLVM_CONFIG --libs --system-libs
> $LLVM_CONFIG_LINK_ARGS $pgac_components`; do
> case $pgac_option in
> -l*) LLVM_LIBS="$LLVM_LIBS $pgac_option";;
> esac
> diff --git a/configure b/configure
> index 86ffccb1ee..974b7f2d4e 100755
> --- a/configure
> +++ b/configure
> @@ -1595,6 +1595,8 @@ Some influential environment variables:
> CXX C++ compiler command
> CXXFLAGS C++ compiler flags
> LLVM_CONFIG path to llvm-config command
> + LLVM_CONFIG_LINK_ARGS
> + extra arguments for llvm-config linker related flags
> CLANG path to clang compiler to generate bitcode
> CPP C preprocessor
> PKG_CONFIG path to pkg-config utility
> @@ -5200,7 +5202,7 @@ fi
> esac
> done
>
> - for pgac_option in `$LLVM_CONFIG --ldflags`; do
> + for pgac_option in `$LLVM_CONFIG --ldflags $LLVM_CONFIG_LINK_ARGS`; do
> case $pgac_option in
> -L*) LDFLAGS="$LDFLAGS $pgac_option";;
> esac
> @@ -5232,7 +5234,7 @@ fi
> # And then get the libraries that need to be linked in for the
> # selected components. They're large libraries, we only want to
> # link them into the LLVM using shared library.
> - for pgac_option in `$LLVM_CONFIG --libs --system-libs
> $pgac_components`; do
> + for pgac_option in `$LLVM_CONFIG --libs --system-libs
> $LLVM_CONFIG_LINK_ARGS $pgac_components`; do
> case $pgac_option in
> -l*) LLVM_LIBS="$LLVM_LIBS $pgac_option";;
> esac
> --
> 2.40.1
>
>