Implement function multi versioning in sysimg

.travis.yml

@@ -101,6 +101,7 @@ before_install:
         export JULIA_CPU_CORES=2;
         export JULIA_TEST_MAXRSS_MB=600;
         TESTSTORUN="all --skip linalg/triangular subarray"; fi # TODO: re enable these if possible without timing out
+    - echo "override JULIA_CPU_TARGET=generic;native" >> Make.user
     - git clone -q git://git.kitenet.net/moreutils
 script:
     - echo BUILDOPTS=$BUILDOPTS

Make.inc

@@ -81,11 +81,6 @@ HAVE_SSP := 0
 WITH_GC_VERIFY := 0
 WITH_GC_DEBUG_ENV := 0
 
-# When set, give julia binaries CPUID specific names. This is useful in cluster environments
-# with heterogeneous architectures. N.B.: will not be automatically rebuilt for all
-# architectures if julia is updated.
-CPUID_SPECIFIC_BINARIES ?= 0
-
 # Prevent picking up $ARCH from the environment variables
 ARCH:=
 

Makefile

@@ -102,17 +102,11 @@ julia-ui-release julia-ui-debug : julia-ui-% : julia-src-%
 julia-inference : julia-base julia-ui-$(JULIA_BUILD_MODE) $(build_prefix)/.examples
 	@$(MAKE) $(QUIET_MAKE) -C $(BUILDROOT) $(build_private_libdir)/inference.ji JULIA_BUILD_MODE=$(JULIA_BUILD_MODE)
 
-ifneq ($(CPUID_SPECIFIC_BINARIES), 0)
-CPUID_TAG = _$(call exec,$(JULIA_EXECUTABLE) --cpuid)
-else
-CPUID_TAG =
-endif
-
 julia-sysimg-release : julia-inference julia-ui-release
-	@$(MAKE) $(QUIET_MAKE) -C $(BUILDROOT) $(build_private_libdir)/sys$(CPUID_TAG).$(SHLIB_EXT) JULIA_BUILD_MODE=release
+	@$(MAKE) $(QUIET_MAKE) -C $(BUILDROOT) $(build_private_libdir)/sys.$(SHLIB_EXT) JULIA_BUILD_MODE=release
 
 julia-sysimg-debug : julia-inference julia-ui-debug
-	@$(MAKE) $(QUIET_MAKE) -C $(BUILDROOT) $(build_private_libdir)/sys-debug$(CPUID_TAG).$(SHLIB_EXT) JULIA_BUILD_MODE=debug
+	@$(MAKE) $(QUIET_MAKE) -C $(BUILDROOT) $(build_private_libdir)/sys-debug.$(SHLIB_EXT) JULIA_BUILD_MODE=debug
 
 julia-debug julia-release : julia-% : julia-ui-% julia-sysimg-% julia-symlink julia-libccalltest
 
@@ -229,13 +223,8 @@ $$(build_private_libdir)/sys$1.o: $$(build_private_libdir)/inference.ji $$(JULIA
 	fi )
 .SECONDARY: $(build_private_libdir)/sys$1.o
 endef
-ifneq ($(CPUID_SPECIFIC_BINARIES),0)
-$(eval $(call sysimg_builder,_%,-O3,$(JULIA_EXECUTABLE_release)))
-$(eval $(call sysimg_builder,-debug_%,-O0,$(JULIA_EXECUTABLE_debug)))
-else
 $(eval $(call sysimg_builder,,-O3,$(JULIA_EXECUTABLE_release)))
 $(eval $(call sysimg_builder,-debug,-O0,$(JULIA_EXECUTABLE_debug)))
-endif
 
 $(build_depsbindir)/stringreplace: $(JULIAHOME)/contrib/stringreplace.c | $(build_depsbindir)
 	@$(call PRINT_CC, $(HOSTCC) -o $(build_depsbindir)/stringreplace $(JULIAHOME)/contrib/stringreplace.c)

base/pkg/pkg.jl

@@ -86,8 +86,6 @@ init(meta::AbstractString=DEFAULT_META, branch::AbstractString=META_BRANCH) = Di
 
 function __init__()
     vers = "v$(VERSION.major).$(VERSION.minor)"
-    vers = ccall(:jl_uses_cpuid_tag, Cint, ()) == 0 ? vers :
-        joinpath(vers,hex(ccall(:jl_cpuid_tag, UInt64, ()), 2*sizeof(UInt64)))
     unshift!(Base.LOAD_CACHE_PATH, abspath(Dir._pkgroot(), "lib", vers))
 end
 

contrib/windows/appveyor_build.sh

@@ -53,6 +53,7 @@ else
   echo 'LIBBLAS = -L$(JULIAHOME)/usr/bin -lopenblas' >> Make.user
   echo 'LIBBLASNAME = libopenblas' >> Make.user
 fi
+echo "override JULIA_CPU_TARGET=generic;native" >> Make.user
 
 # Set XC_HOST if in Cygwin or Linux
 case $(uname) in

doc/src/devdocs/sysimg.md

@@ -38,3 +38,68 @@ and `force` set to `true`, one would execute:
 ```
 julia build_sysimg.jl /tmp/sys core2 ~/userimg.jl --force
 ```
+
+## System image optimized for multiple microarchitectures
+
+The system image can be compiled simultaneously for multiple CPU microarchitectures
+under the same instruction set architecture (ISA). Multiple versions of the same function
+may be created with minimum dispatch point inserted into shared functions
+in order to take advantage of different ISA extensions or other microarchitecture features.
+The version that offers the best performance will be selected automatically at runtime
+based on available features.
+
+### Specifying multiple system image targets
+
+Multi-microarch system image can be enabled by passing multiple targets
+during system image compilation. This can be done either with the `JULIA_CPU_TARGET` make option
+or with the `-C` command line option when running the compilation command manually.
+Multiple targets are separated by `;` in the option.
+The syntax for each target is a CPU name followed by multiple features separated by `,`.
+All features supported by LLVM is supported and a feature can be disabled with a `-` prefix.
+(`+` prefix is also allowed and ignored to be consistent with LLVM syntax).
+Additionally, two special features are supported to control the function cloning behavior.
+
+1. `clone_all`
+
+    By default, only functions that are the most likely to benefit from
+    the microarchitecture features will be cloned.
+    When `clone_all` is specified for a target, however,
+    **all** functions in the system image will be cloned for the target.
+    The negative form `-clone_all` can be used to prevent the built-in
+    heuristic from cloning all functions.
+
+2. `base(<n>)`
+
+    Where `<n>` is a placeholder for a non-negative number (e.g. `base(0)`, `base(1)`).
+    By default, a partially cloned (i.e. not `clone_all`) target will use functions
+    from the default target (first one specified) if a function is not cloned.
+    This behavior can be changed by specifying a different base with the `base(<n>)` option.
+    The `n`th target (0-based) will be used as the base target instead of the default (`0`th) one.
+    The base target has to be either `0` or another `clone_all` target.
+    Specifying a non default `clone_all` target as the base target will cause an error.
+
+### Implementation overview
+
+This is a brief overview of different part involved in the implementation.
+See code comments for each components for more implementation details.
+
+1. System image compilation
+
+    The parsing and cloning decision are done in `src/processor*`.
+    We currently support cloning of function based on the present of loops, simd instructions,
+    or other math operations (e.g. fastmath, fma, muladd).
+    This information is passed on to `src/llvm-multiversioning.cpp` which does the actual cloning.
+    In addition to doing the cloning and insert dispatch slots
+    (see comments in `MultiVersioning::runOnModule` for how this is done),
+    the pass also generates metadata so that the runtime can load and initialize the
+    system image correctly.
+    A detail description of the metadata is available in `src/processor.h`.
+
+2. System image loading
+
+    The loading and initialization of the system image is done in `src/processor*` by
+    parsing the metadata saved during system image generation.
+    Host feature detection and selection decision are done in `src/processor_*.cpp`
+    depending on the ISA. The target selection will prefer exact CPU name match,
+    larger vector register size, and larget number of features.
+    An overview of this process is in `src/processor.cpp`.

src/Makefile

@@ -41,7 +41,7 @@ SRCS := \
 	simplevector APInt-C runtime_intrinsics runtime_ccall precompile \
 	threadgroup threading stackwalk gc gc-debug gc-pages method \
 	jlapi signal-handling safepoint jloptions timing subtype rtutils \
-	crc32c
+	crc32c processor
 
 ifeq ($(USEMSVC), 1)
 SRCS += getopt
@@ -52,7 +52,7 @@ LLVMLINK :=
 ifeq ($(JULIACODEGEN),LLVM)
 SRCS += codegen jitlayers disasm debuginfo llvm-simdloop llvm-ptls llvm-muladd \
 	llvm-late-gc-lowering llvm-lower-handlers llvm-gc-invariant-verifier \
-	llvm-propagate-addrspaces llvm-alloc-opt cgmemmgr
+	llvm-propagate-addrspaces llvm-multiversioning llvm-alloc-opt cgmemmgr
 FLAGS += -I$(shell $(LLVM_CONFIG_HOST) --includedir)
 LLVM_LIBS := all
 ifeq ($(USE_POLLY),1)
@@ -109,10 +109,6 @@ SHIPFLAGS += $(FLAGS)
 SHIPFLAGS += "-DJL_SYSTEM_IMAGE_PATH=\"$(build_private_libdir_rel)/sys.$(SHLIB_EXT)\""
 DEBUGFLAGS += "-DJL_SYSTEM_IMAGE_PATH=\"$(build_private_libdir_rel)/sys-debug.$(SHLIB_EXT)\""
 
-ifneq ($(CPUID_SPECIFIC_BINARIES), 0)
-override CPPFLAGS += "-DCPUID_SPECIFIC_BINARIES=1"
-endif
-
 FLISP_EXECUTABLE_debug := $(BUILDDIR)/flisp/flisp-debug
 FLISP_EXECUTABLE_release := $(BUILDDIR)/flisp/flisp
 ifeq ($(OS),WINNT)
@@ -186,12 +182,15 @@ $(BUILDDIR)/julia_flisp.boot: $(addprefix $(SRCDIR)/,jlfrontend.scm flisp/aliase
 # additional dependency links
 $(BUILDDIR)/ast.o $(BUILDDIR)/ast.dbg.obj: $(BUILDDIR)/julia_flisp.boot.inc $(SRCDIR)/flisp/*.h
 $(BUILDDIR)/codegen.o $(BUILDDIR)/codegen.dbg.obj: $(addprefix $(SRCDIR)/,\
-	intrinsics.cpp jitlayers.h intrinsics.h debuginfo.h codegen_shared.h cgutils.cpp ccall.cpp abi_*.cpp)
+	intrinsics.cpp jitlayers.h intrinsics.h debuginfo.h codegen_shared.h cgutils.cpp ccall.cpp abi_*.cpp processor.h)
+$(BUILDDIR)/processor.o $(BUILDDIR)/processor.dbg.obj: $(addprefix $(SRCDIR)/,processor_*.cpp processor.h features_*.h)
 $(BUILDDIR)/anticodegen.o $(BUILDDIR)/anticodegen.dbg.obj: $(SRCDIR)/intrinsics.h
-$(BUILDDIR)/debuginfo.o $(BUILDDIR)/debuginfo.dbg.obj: $(SRCDIR)/debuginfo.h
-$(BUILDDIR)/disasm.o $(BUILDDIR)/disasm.dbg.obj: $(SRCDIR)/debuginfo.h
+$(BUILDDIR)/debuginfo.o $(BUILDDIR)/debuginfo.dbg.obj: \
+	$(addprefix $(SRCDIR)/,debuginfo.h processor.h)
+$(BUILDDIR)/disasm.o $(BUILDDIR)/disasm.dbg.obj: $(SRCDIR)/debuginfo.h $(SRCDIR)/processor.h
 $(BUILDDIR)/jitlayers.o $(BUILDDIR)/jitlayers.dbg.obj: $(SRCDIR)/jitlayers.h
 $(BUILDDIR)/builtins.o $(BUILDDIR)/builtins.dbg.obj: $(SRCDIR)/table.c
+$(BUILDDIR)/staticdata.o $(BUILDDIR)/staticdata.dbg.obj: $(SRCDIR)/processor.h
 $(BUILDDIR)/gc.o $(BUILDDIR)/gc.dbg.obj: $(SRCDIR)/gc.h
 $(BUILDDIR)/gc-debug.o $(BUILDDIR)/gc-debug.dbg.obj: $(SRCDIR)/gc.h
 $(BUILDDIR)/gc-pages.o $(BUILDDIR)/gc-pages.dbg.obj: $(SRCDIR)/gc.h

src/anticodegen.c

@@ -36,10 +36,10 @@ int jl_getFunctionInfo(jl_frame_t **frames, uintptr_t pointer, int skipC, int no
     return 0;
 }
 
-void jl_register_fptrs(uint64_t sysimage_base, const char *base, const int32_t *offsets,
+void jl_register_fptrs(uint64_t sysimage_base, const struct _jl_sysimg_fptrs_t *fptrs,
                        jl_method_instance_t **linfos, size_t n)
 {
-    (void)sysimage_base; (void)base; (void)offsets; (void)linfos; (void)n;
+    (void)sysimage_base; (void)fptrs; (void)linfos; (void)n;
 }
 
 void jl_compile_linfo(jl_method_instance_t *li) { }