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anarazelanarazel
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Add inlining support to LLVM JIT provider.
This provides infrastructure to allow JITed code to inline code implemented in C. This e.g. can be postgres internal functions or extension code. This already speeds up long running queries, by allowing the LLVM optimizer to optimize across function boundaries. The optimization potential currently doesn't reach its full potential because LLVM cannot optimize the FunctionCallInfoData argument fully away, because it's allocated on the heap rather than the stack. Fixing that is beyond what's realistic for v11. To be able to do that, use CLANG to convert C code to LLVM bitcode, and have LLVM build a summary for it. That bitcode can then be used to to inline functions at runtime. For that the bitcode needs to be installed. Postgres bitcode goes into $pkglibdir/bitcode/postgres, extensions go into equivalent directories. PGXS has been modified so that happens automatically if postgres has been compiled with LLVM support. Currently this isn't the fastest inline implementation, modules are reloaded from disk during inlining. That's to work around an apparent LLVM bug, triggering an apparently spurious error in LLVM assertion enabled builds. Once that is resolved we can remove the superfluous read from disk. Docs will follow in a later commit containing docs for the whole JIT feature. Author: Andres Freund Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
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‎src/Makefile.global.in

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Original file line numberDiff line numberDiff line change
@@ -171,6 +171,7 @@ endif # PGXS
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includedir_server = $(pkgincludedir)/server
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includedir_internal = $(pkgincludedir)/internal
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pgxsdir = $(pkglibdir)/pgxs
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bitcodedir = $(pkglibdir)/bitcode
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##########################################################################
@@ -972,3 +973,36 @@ endif
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%.bc : %.cpp
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$(COMPILE.cxx.bc) -o $@ $<
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# Install LLVM bitcode module (for JITing).
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#
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# The arguments are:
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# $(1) name of the module (e.g. an extension's name or postgres for core code)
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# $(2) source objects, with .o suffix
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#
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define install_llvm_module
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# Create target directory
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$(MKDIR_P) "$(DESTDIR)${bitcodedir}/$(1)"
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# Create sub-directories, if files are in subdirectories
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$(MKDIR_P) $(sort $(dir $(addprefix $(DESTDIR)${bitcodedir}/$(1)/, $(2))))
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# Then install files
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#
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# The many INSTALL_DATA invocations aren't particularly fast, it'd be
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# good if we could coalesce them, but I didn't find a good way.
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$(foreach obj, ${2}, $(INSTALL_DATA) $(patsubst %.o,%.bc, $(obj)) $(DESTDIR)/${bitcodedir}/$(1)/$(dir $(obj));
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)
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# and generate index
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(cd "$(DESTDIR)${bitcodedir}" && $(LLVM_BINPATH)/llvm-lto -thinlto -thinlto-action=thinlink -o $(1).index.bc $(addprefix $(1)/,$(patsubst %.o,%.bc, $(2))))
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endef
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# Uninstall LLVM bitcode module.
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#
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# The arguments are:
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# $(1) name of the module (e.g. an extension's name or postgres for core code)
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#
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# This intentionally doesn't use the explicit installed file list,
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# seems too likely to change regularly.
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define uninstall_llvm_module
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rm -rf "$(DESTDIR)${bitcodedir}/$(1)/"
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rm -f "$(DESTDIR)${bitcodedir}/$(1).index.bc"
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endef

‎src/backend/Makefile

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Original file line numberDiff line numberDiff line change
@@ -252,6 +252,13 @@ endif
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$(INSTALL_DATA) $(srcdir)/utils/misc/postgresql.conf.sample '$(DESTDIR)$(datadir)/postgresql.conf.sample'
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$(INSTALL_DATA) $(srcdir)/access/transam/recovery.conf.sample '$(DESTDIR)$(datadir)/recovery.conf.sample'
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ifeq ($(with_llvm), yes)
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install-bin: install-postgres-bitcode
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install-postgres-bitcode: $(OBJS) all
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$(call install_llvm_module,postgres,$(call expand_subsys, $(filter-out $(top_builddir)/src/timezone/objfiles.txt, $(SUBDIROBJS))))
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endif
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install-bin: postgres $(POSTGRES_IMP) installdirs
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$(INSTALL_PROGRAM) postgres$(X) '$(DESTDIR)$(bindir)/postgres$(X)'
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ifneq ($(PORTNAME), win32)
@@ -309,6 +316,9 @@ endif
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'$(DESTDIR)$(datadir)/pg_ident.conf.sample' \
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'$(DESTDIR)$(datadir)/postgresql.conf.sample' \
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'$(DESTDIR)$(datadir)/recovery.conf.sample'
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ifeq ($(with_llvm), yes)
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$(call uninstall_llvm_module,postgres)
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endif
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##########################################################################

‎src/backend/common.mk

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Original file line numberDiff line numberDiff line change
@@ -30,6 +30,10 @@ objfiles.txt: Makefile $(SUBDIROBJS) $(OBJS)
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# Don't rebuild the list if only the OBJS have changed.
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$(if $(filter-out $(OBJS),$?),( $(if $(SUBDIROBJS),cat $(SUBDIROBJS); )echo $(addprefix $(subdir)/,$(OBJS)) ) >$@,touch $@)
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ifeq ($(with_llvm), yes)
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objfiles.txt: $(patsubst %.o,%.bc, $(OBJS))
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endif
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# make function to expand objfiles.txt contents
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expand_subsys = $(foreach file,$(1),$(if $(filter %/objfiles.txt,$(file)),$(patsubst ../../src/backend/%,%,$(addprefix $(top_builddir)/,$(shell cat $(file)))),$(file)))
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@@ -43,7 +47,7 @@ $(SUBDIRS:%=%-recursive):
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$(call recurse,clean)
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clean: clean-local
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clean-local:
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rm -f $(subsysfilename) $(OBJS)
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rm -f $(subsysfilename) $(OBJS) $(patsubst %.o,%.bc, $(OBJS))
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$(call recurse,coverage)
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$(call recurse,install)

‎src/backend/jit/jit.c

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@@ -40,6 +40,7 @@ bool jit_expressions = true;
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bool jit_profiling_support = false;
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bool jit_tuple_deforming = true;
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double jit_above_cost = 100000;
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double jit_inline_above_cost = 500000;
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double jit_optimize_above_cost = 500000;
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static JitProviderCallbacks provider;

‎src/backend/jit/llvm/Makefile

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Original file line numberDiff line numberDiff line change
@@ -37,7 +37,7 @@ override COMPILER = $(CXX) $(CFLAGS)
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OBJS=$(WIN32RES)
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# Infrastructure
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OBJS += llvmjit.o llvmjit_error.o llvmjit_wrap.o
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OBJS += llvmjit.o llvmjit_error.o llvmjit_inline.o llvmjit_wrap.o
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# Code generation
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OBJS += llvmjit_expr.o llvmjit_deform.o
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‎src/backend/jit/llvm/llvmjit.c

Lines changed: 16 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -468,6 +468,10 @@ llvm_optimize_module(LLVMJitContext *context, LLVMModuleRef module)
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/* always use always-inliner pass */
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if (!(context->base.flags & PGJIT_OPT3))
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LLVMAddAlwaysInlinerPass(llvm_mpm);
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/* if doing inlining, but no expensive optimization, add inlining pass */
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if (context->base.flags & PGJIT_INLINE
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&& !(context->base.flags & PGJIT_OPT3))
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LLVMAddFunctionInliningPass(llvm_mpm);
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LLVMRunPassManager(llvm_mpm, context->module);
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LLVMDisposePassManager(llvm_mpm);
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@@ -491,6 +495,16 @@ llvm_compile_module(LLVMJitContext *context)
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else
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compile_orc = llvm_opt0_orc;
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/* perform inlining */
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if (context->base.flags & PGJIT_INLINE)
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{
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INSTR_TIME_SET_CURRENT(starttime);
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llvm_inline(context->module);
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INSTR_TIME_SET_CURRENT(endtime);
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INSTR_TIME_ACCUM_DIFF(context->base.inlining_counter,
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endtime, starttime);
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}
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if (jit_dump_bitcode)
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{
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char *filename;
@@ -578,7 +592,8 @@ llvm_compile_module(LLVMJitContext *context)
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MemoryContextSwitchTo(oldcontext);
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ereport(DEBUG1,
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(errmsg("time to opt: %.3fs, emit: %.3fs",
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(errmsg("time to inline: %.3fs, opt: %.3fs, emit: %.3fs",
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INSTR_TIME_GET_DOUBLE(context->base.inlining_counter),
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INSTR_TIME_GET_DOUBLE(context->base.optimization_counter),
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INSTR_TIME_GET_DOUBLE(context->base.emission_counter)),
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errhidestmt(true),

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