postgresql/config/llvm.m4
Andres Freund 240d40db88 Detect LLVM 7 without specifying binaries explicitly.
Before this commit LLVM 7 was supported, but only if one explicitly
provided LLVM_CONFIG= and CLANG= paths.  As LLVM 7 is the first
version that includes our upstreamed debugging and profiling features,
and as debian is planning to default to 7 due to wider architecture
support, it seems good to support auto-detecting that version.

Author: Christoph Berg
Discussion: https://postgr.es/m/20180912124517.GD24584@msg.df7cb.de
Backpatch: 11, where LLVM was introduced
2018-09-13 10:42:11 -07:00

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# config/llvm.m4
# PGAC_LLVM_SUPPORT
# ---------------
#
# Look for the LLVM installation, check that it's new enough, set the
# corresponding LLVM_{CFLAGS,CXXFLAGS,BINPATH} and LDFLAGS
# variables. Also verifies that CLANG is available, to transform C
# into bitcode.
#
AC_DEFUN([PGAC_LLVM_SUPPORT],
[
AC_REQUIRE([AC_PROG_AWK])
AC_ARG_VAR(LLVM_CONFIG, [path to llvm-config command])
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
if test -z "$LLVM_CONFIG"; then
AC_MSG_ERROR([llvm-config not found, but required when compiling --with-llvm, specify with LLVM_CONFIG=])
fi
# check if detected $LLVM_CONFIG is executable
pgac_llvm_version="$($LLVM_CONFIG --version 2> /dev/null || echo no)"
if test "x$pgac_llvm_version" = "xno"; then
AC_MSG_ERROR([$LLVM_CONFIG does not work])
fi
# and whether the version is supported
if echo $pgac_llvm_version | $AWK -F '.' '{ if ([$]1 >= 4 || ([$]1 == 3 && [$]2 >= 9)) exit 1; else exit 0;}';then
AC_MSG_ERROR([$LLVM_CONFIG version is $pgac_llvm_version but at least 3.9 is required])
fi
# need clang to create some bitcode files
AC_ARG_VAR(CLANG, [path to clang compiler to generate bitcode])
PGAC_PATH_PROGS(CLANG, clang clang-7 clang-6.0 clang-5.0 clang-4.0 clang-3.9)
if test -z "$CLANG"; then
AC_MSG_ERROR([clang not found, but required when compiling --with-llvm, specify with CLANG=])
fi
# make sure clang is executable
if test "x$($CLANG --version 2> /dev/null || echo no)" = "xno"; then
AC_MSG_ERROR([$CLANG does not work])
fi
# Could check clang version, but it doesn't seem that
# important. Systems with a new enough LLVM version are usually
# going to have a decent clang version too. It's also not entirely
# clear what the minimum version is.
# Collect compiler flags necessary to build the LLVM dependent
# shared library.
for pgac_option in `$LLVM_CONFIG --cppflags`; do
case $pgac_option in
-I*|-D*) LLVM_CPPFLAGS="$pgac_option $LLVM_CPPFLAGS";;
esac
done
for pgac_option in `$LLVM_CONFIG --ldflags`; do
case $pgac_option in
-L*) LDFLAGS="$LDFLAGS $pgac_option";;
esac
done
# ABI influencing options, standard influencing options
for pgac_option in `$LLVM_CONFIG --cxxflags`; do
case $pgac_option in
-fno-rtti*) LLVM_CXXFLAGS="$LLVM_CXXFLAGS $pgac_option";;
-std=*) LLVM_CXXFLAGS="$LLVM_CXXFLAGS $pgac_option";;
esac
done
# Look for components we're interested in, collect necessary
# libs. As some components are optional, we can't just list all of
# them as it'd raise an error.
pgac_components='';
for pgac_component in `$LLVM_CONFIG --components`; do
case $pgac_component in
engine) pgac_components="$pgac_components $pgac_component";;
debuginfodwarf) pgac_components="$pgac_components $pgac_component";;
orcjit) pgac_components="$pgac_components $pgac_component";;
passes) pgac_components="$pgac_components $pgac_component";;
perfjitevents) pgac_components="$pgac_components $pgac_component";;
esac
done;
# And then get the libraries that need to be linked in for the
# selected components. They're large libraries, we only want to
# link them into the LLVM using shared library.
for pgac_option in `$LLVM_CONFIG --libs --system-libs $pgac_components`; do
case $pgac_option in
-l*) LLVM_LIBS="$LLVM_LIBS $pgac_option";;
esac
done
LLVM_BINPATH=`$LLVM_CONFIG --bindir`
# Check which functionality is present
SAVE_CPPFLAGS="$CPPFLAGS"
CPPFLAGS="$CPPFLAGS $LLVM_CPPFLAGS"
AC_CHECK_DECLS([LLVMOrcGetSymbolAddressIn], [], [], [[#include <llvm-c/OrcBindings.h>]])
AC_CHECK_DECLS([LLVMGetHostCPUName, LLVMGetHostCPUFeatures], [], [], [[#include <llvm-c/TargetMachine.h>]])
AC_CHECK_DECLS([LLVMCreateGDBRegistrationListener, LLVMCreatePerfJITEventListener], [], [], [[#include <llvm-c/ExecutionEngine.h>]])
CPPFLAGS="$SAVE_CPPFLAGS"
# LLVM_CONFIG, CLANG are already output via AC_ARG_VAR
AC_SUBST(LLVM_LIBS)
AC_SUBST(LLVM_CPPFLAGS)
AC_SUBST(LLVM_CFLAGS)
AC_SUBST(LLVM_CXXFLAGS)
AC_SUBST(LLVM_BINPATH)
])# PGAC_LLVM_SUPPORT