Mixed use of compilers to build sources

[strk]

As odd as it seems, running make ends up using a mix of gcc and clang-14 on my system. Even for the same file. For example, under raster/rt_pg, an extract of the build logs:

grep rtpg_pixel.c build.log # returns:

gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Werror=vla -Wendif-labels -Wmissing-format-attribute -Wimplicit-fallthrough=3 -Wcast-function-type -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -Wno-format-truncation -Wno-stringop-truncation -g -g -O2 -fstack-protector-strong -Wformat -Werror=format-security -fno-omit-frame-pointer -fPIC -I../../liblwgeom -I../../liblwgeom -I/usr/local/include  -I/usr/include/x86_64-linux-gnu   -I/usr/include/libxml2  -I/usr/include/json-c   -DNDEBUG -std=gnu99 -O2 -g -Wall -Wsuggest-attribute=format -fno-math-errno -fno-signed-zeros -Wall -O2 -I/usr/local/include -I../../libpgcommon -I/usr/include/x86_64-linux-gnu -I./../rt_core -I. -I./.. -I../.. -I. -I./ -I/usr/include/postgresql/15/server -I/usr/include/postgresql/internal  -Wdate-time -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -I/usr/include/libxml2   -c -o rtpg_pixel.o rtpg_pixel.c
/usr/bin/clang-14 -Wno-ignored-attributes -fno-strict-aliasing -fwrapv -Wno-unused-command-line-argument -Wno-compound-token-split-by-macro -O2  -I../../liblwgeom -I../../liblwgeom -I/usr/local/include  -I/usr/include/x86_64-linux-gnu   -I/usr/include/libxml2  -I/usr/include/json-c   -DNDEBUG -std=gnu99 -O2 -g -Wall -Wsuggest-attribute=format -fno-math-errno -fno-signed-zeros -Wall -O2 -I/usr/local/include -I../../libpgcommon -I/usr/include/x86_64-linux-gnu -I./../rt_core -I. -I./.. -I../.. -I. -I./ -I/usr/include/postgresql/15/server -I/usr/include/postgresql/internal  -Wdate-time -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -I/usr/include/libxml2  -flto=thin -emit-llvm -c -o rtpg_pixel.bc rtpg_pixel.c

It does look like something about LLVM but I don't see where that line comes from. I guess it's from PGXS.

The problem with this mix of compilers is that the same CFLAGS are passed to both but some flags are only supported by one compiler and not the other.

[strk]

A possible way to disable llvm: ​https://www.postgresql.org/message-id/CACpMh%2BBAM9j6ML%3DeaS3i7uW%3DzOzkzOuwv%3D%2BfHiMhstKhCt%3DwvQ%40mail.gmail.com

Whether or not we want to do that I'm not sure.

[strk]

make with_llvm=no fixes the problem for me

[strk]

override with_llvm=no before the include of PGXS fixes it too

[robe]

@strk we need to remove PGXS from our logic. We should do so before PostGIS 3.5. I thought I had this ticketed somewhere.

The plan of PostgreSQL group is to get rid of PGXS and autoconf in favor of Meson. They've already switched most of their buildfarms to test using meson. E.g there msys/mingw no longer tests with autoconf, uses meson strictly. Last I checked they are working out some kinks with VS Studio (the usual problem child).

That said I believe Meson is the official build tool for PG17 and up. Come PG18 or later, they plan to completely remove autoconf.

[robe]

ah yes have it ticketed at #5281.

I've set to do for 3.5.0 milestone