meson: Add LLVM bitcode emission

This needs a bit more love before being ready...

Author: anarazel

contrib/citext/meson.build

@@ -40,3 +40,8 @@ tests += {
     ],
   },
 }
+
+bitcode_modules += {
+  'target': citext,
+  'srcfiles': citext_sources,
+}

meson.build

@@ -771,6 +771,8 @@ if add_languages('cpp', required: llvmopt, native: false)
 
     ccache = find_program('ccache', native: true, required: false)
     clang = find_program(llvm_binpath / 'clang', required: true)
+    llvm_lto = find_program(llvm_binpath / 'llvm-lto', required: true)
+    irlink = find_program('src/tools/irlink', native: true)
   endif
 elif llvmopt.auto()
   message('llvm requires a C++ compiler')
@@ -2601,6 +2603,10 @@ nls_targets = []
 test_deps = []
 tests = []
 
+# List of object files + source files to generated LLVM IR for inlining.
+# Each element is a hash of {'target': target, 'srcfiles': ...}.
+bitcode_modules = []
+
 
 # Default options for targets
 
@@ -2923,6 +2929,11 @@ subdir('src/interfaces/ecpg/test')
 
 subdir('doc/src/sgml')
 
+# generate bitcode for JIT inlining after giving contrib modules etc a chance
+# to add themselves to bitcode_modules[]
+subdir('src/backend/jit/llvm/bitcode', if_found: llvm)
+
+
 generated_sources_ac += {'': ['GNUmakefile']}
 
 # After processing src/test, add test_install_libs to the testprep_targets
@@ -3437,6 +3448,15 @@ if meson.version().version_compare('>=0.57')
     section: 'Programs',
   )
 
+  if llvm.found()
+    summary(
+      {
+        'clang': clang,
+      },
+      section: 'Programs',
+    )
+  endif
+
   summary(
     {
       'bonjour': bonjour,

src/backend/jit/llvm/bitcode/meson.build

@@ -0,0 +1,40 @@
+# Copyright (c) 2022-2023, PostgreSQL Global Development Group
+#
+# emit LLVM bitcode for JIT inlining
+
+assert(llvm.found())
+
+foreach bitcode_module : bitcode_modules
+  bitcode_targets = []
+  bitcode_obj = bitcode_module['target']
+  if 'name' not in bitcode_module
+    bitcode_name = bitcode_obj.name()
+  else
+    bitcode_name = bitcode_module['name']
+  endif
+
+  foreach srcfile : bitcode_module['srcfiles']
+    srcfilename = '@0@'.format(srcfile)
+    targetname = '@0@_@1@_@[email protected]'.format(
+      bitcode_name,
+      fs.parent(srcfilename).underscorify(), fs.name(srcfilename))
+    bitcode_targets += custom_target(
+      targetname,
+      input: [srcfile, bitcode_obj.extract_objects(srcfile)],
+      output: targetname,
+      command: [llvm_irgen_command, bitcode_cflags],
+      install: true,
+      install_dir: dir_bitcode,
+    )
+  endforeach
+
+  index_name = '@[email protected]'.format(bitcode_name)
+  bitcode_index = custom_target('@0@'.format(bitcode_name),
+    output: index_name,
+    input: bitcode_targets,
+    command: [irlink, '--lto', llvm_lto, '--outdir', '@OUTDIR@', '--index', index_name, '@INPUT@'],
+    install: true,
+    install_dir: dir_bitcode,
+  )
+  backend_targets += bitcode_index
+endforeach

src/backend/jit/llvm/meson.build

@@ -41,21 +41,20 @@ backend_targets += llvmjit
 
 # Define a few bits and pieces used here and elsewhere to generate bitcode
 
-llvm_irgen_args = [
-  '-c', '-o', '@OUTPUT@', '@INPUT@',
+llvm_irgen_command = []
+if ccache.found()
+  llvm_irgen_command += ccache
+endif
+
+llvm_irgen_command += [
+  clang,
+  '-c', '-o', '@OUTPUT0@', '@INPUT0@',
   '-flto=thin', '-emit-llvm',
-  '-MD', '-MQ', '@OUTPUT@', '-MF', '@DEPFILE@',
   '-O2',
   '-Wno-ignored-attributes',
   '-Wno-empty-body',
 ]
-
-if ccache.found()
-  llvm_irgen_command = ccache
-  llvm_irgen_args = [clang.path()] + llvm_irgen_args
-else
-  llvm_irgen_command = clang
-endif
+llvm_irgen_dep_args = ['-MD', '-MQ', '@OUTPUT0@', '-MF', '@DEPFILE@']
 
 
 # XXX: Need to determine proper version of the function cflags for clang
@@ -74,7 +73,7 @@ bitcode_cflags += '-I@SOURCE_ROOT@/src/include'
 # Note this is intentionally not installed to bitcodedir, as it's not for
 # inlining
 llvmjit_types = custom_target('llvmjit_types.bc',
-  command: [llvm_irgen_command] + llvm_irgen_args + bitcode_cflags,
+  command: llvm_irgen_command + llvm_irgen_dep_args + bitcode_cflags,
   input: 'llvmjit_types.c',
   output: 'llvmjit_types.bc',
   depends: [postgres],
@@ -83,3 +82,11 @@ llvmjit_types = custom_target('llvmjit_types.bc',
   depfile: '@[email protected]',
 )
 backend_targets += llvmjit_types
+
+# Figure out -I's needed to build all postgres code, including all its
+# dependencies
+pkg_config = find_program(['pkg-config', 'pkgconf'], required: true)
+r = run_command(pkg_config,
+  ['--cflags-only-I', meson.build_root() / 'meson-uninstalled/postgresql-extension-uninstalled.pc'],
+  check: true)
+bitcode_cflags += r.stdout().split()

src/backend/meson.build

@@ -155,6 +155,14 @@ postgres = executable('postgres',
 
 backend_targets += postgres
 
+
+bitcode_modules += {
+  'name': 'postgres',
+  'target': postgres_lib,
+  'srcfiles': backend_sources,
+}
+
+
 pg_mod_c_args = cflags_mod
 pg_mod_cpp_args = cxxflags_mod
 pg_mod_link_args = ldflags_sl + ldflags_mod

src/tools/irlink

@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+
+import os
+import shutil
+import subprocess
+import sys
+import argparse
+
+parser = argparse.ArgumentParser(
+    description='generate PostgreSQL JIT IR module')
+
+parser.add_argument('--index', type=str, required=True)
+parser.add_argument('--lto', type=str, required=True)
+parser.add_argument('--outdir', type=str, required=True)
+parser.add_argument('INPUT', type=str, nargs='+')
+
+args = parser.parse_args()
+
+file_names = [os.path.basename(f) for f in args.INPUT]
+command = [args.lto,
+           '-thinlto', '-thinlto-action=thinlink',
+           '-o', args.index] + file_names
+res = subprocess.run(command, cwd=args.outdir)
+
+exit(res.returncode)