Merge pull request #284 from feast-dev/dynamic-linking

Add optional dynamic linking when building shared library

Author: rcoreilly

bind/gen.go

@@ -434,14 +434,15 @@ var NoMake = false
 // and wrapper .py file(s) that are loaded as the interface to the package with shadow
 // python-side classes
 // mode = gen, build, pkg, exe
-func GenPyBind(mode BuildMode, libext, extragccargs string, lang int, cfg *BindCfg) error {
+func GenPyBind(mode BuildMode, libext, extragccargs string, lang int, dynamicLink bool, cfg *BindCfg) error {
 	gen := &pyGen{
 		mode:         mode,
 		pypkgname:    cfg.Name,
 		cfg:          cfg,
 		libext:       libext,
 		extraGccArgs: extragccargs,
 		lang:         lang,
+		dynamicLink:  dynamicLink,
 	}
 	gen.genPackageMap()
 	thePyGen = gen
@@ -470,6 +471,7 @@ type pyGen struct {
 	libext       string
 	extraGccArgs string
 	lang         int // c-python api version (2,3)
+	dynamicLink  bool
 }
 
 func (g *pyGen) gen() error {
@@ -583,12 +585,18 @@ func (g *pyGen) genGoPreamble() {
 		if err != nil {
 			panic(err)
 		}
+		var ldflags string
+		if g.mode == ModeExe || !g.dynamicLink {
+			ldflags = pycfg.LdFlags
+		} else {
+			ldflags = pycfg.LdDynamicFlags
+		}
 		// this is critical to avoid pybindgen errors:
 		exflags := " -Wno-error -Wno-implicit-function-declaration -Wno-int-conversion"
 		pkgcfg := fmt.Sprintf(`
 #cgo CFLAGS: %s
 #cgo LDFLAGS: %s
-`, pycfg.CFlags+exflags, pycfg.LdFlags)
+`, pycfg.CFlags+exflags, ldflags)
 
 		return pkgcfg
 	}()

bind/utils.go

@@ -87,10 +87,11 @@ func isConstructor(sig *types.Signature) bool {
 }
 
 type PyConfig struct {
-	Version   int
-	CFlags    string
-	LdFlags   string
-	ExtSuffix string
+	Version        int
+	CFlags         string
+	LdFlags        string
+	LdDynamicFlags string
+	ExtSuffix      string
 }
 
 // AllFlags returns CFlags + " " + LdFlags
@@ -107,6 +108,12 @@ import json
 import os
 version=sys.version_info.major
 
+def clear_ld_flags(s):
+	skip_first_word = s.split(' ', 1)[1]  # skip compiler name
+	skip_bundle = skip_first_word.replace('-bundle', '')  # cgo already passes -dynamiclib
+	return skip_bundle
+
+
 if "GOPY_INCLUDE" in os.environ and "GOPY_LIBDIR" in os.environ and "GOPY_PYLIB" in os.environ:
 	print(json.dumps({
 		"version": version,
@@ -117,6 +124,7 @@ if "GOPY_INCLUDE" in os.environ and "GOPY_LIBDIR" in os.environ and "GOPY_PYLIB"
 		"shlibs":  ds.get_config_var("SHLIBS"),
 		"syslibs": ds.get_config_var("SYSLIBS"),
 		"shlinks": ds.get_config_var("LINKFORSHARED"),
+		"shflags": clear_ld_flags(ds.get_config_var("LDSHARED")),
 		"extsuffix": ds.get_config_var("EXT_SUFFIX"),
 }))
 else:
@@ -129,6 +137,7 @@ else:
 		"shlibs":  ds.get_config_var("SHLIBS"),
 		"syslibs": ds.get_config_var("SYSLIBS"),
 		"shlinks": ds.get_config_var("LINKFORSHARED"),
+		"shflags": clear_ld_flags(ds.get_config_var("LDSHARED")),
 		"extsuffix": ds.get_config_var("EXT_SUFFIX"),
 }))
 `
@@ -158,6 +167,7 @@ else:
 		ShLibs    string `json:"shlibs"`
 		SysLibs   string `json:"syslibs"`
 		ExtSuffix string `json:"extsuffix"`
+		ShFlags   string `json:"shflags"`
 	}
 	err = json.NewDecoder(buf).Decode(&raw)
 	if err != nil {
@@ -199,6 +209,7 @@ else:
 		raw.ShLibs,
 		raw.SysLibs,
 	}, " ")
+	cfg.LdDynamicFlags = raw.ShFlags
 
 	return cfg, nil
 }

cmd_build.go

@@ -44,6 +44,7 @@ ex:
 	cmd.Flag.Bool("symbols", true, "include symbols in output")
 	cmd.Flag.Bool("no-warn", false, "suppress warning messages, which may be expected")
 	cmd.Flag.Bool("no-make", false, "do not generate a Makefile, e.g., when called from Makefile")
+	cmd.Flag.Bool("dynamic-link", false, "whether to link output shared library dynamically to Python")
 	return cmd
 }
 
@@ -64,6 +65,7 @@ func gopyRunCmdBuild(cmdr *commander.Command, args []string) error {
 	cfg.Symbols = cmdr.Flag.Lookup("symbols").Value.Get().(bool)
 	cfg.NoWarn = cmdr.Flag.Lookup("no-warn").Value.Get().(bool)
 	cfg.NoMake = cmdr.Flag.Lookup("no-make").Value.Get().(bool)
+	cfg.DynamicLinking = cmdr.Flag.Lookup("dynamic-link").Value.Get().(bool)
 
 	bind.NoWarn = cfg.NoWarn
 	bind.NoMake = cfg.NoMake
@@ -212,8 +214,12 @@ func runBuild(mode bind.BuildMode, cfg *BuildCfg) error {
 		if include, exists := os.LookupEnv("GOPY_INCLUDE"); exists {
 			cflags = append(cflags, "-I"+filepath.ToSlash(include))
 		}
-
-		ldflags := strings.Fields(strings.TrimSpace(pycfg.LdFlags))
+		var ldflags []string
+		if cfg.DynamicLinking {
+			ldflags = strings.Fields(strings.TrimSpace(pycfg.LdDynamicFlags))
+		} else {
+			ldflags = strings.Fields(strings.TrimSpace(pycfg.LdFlags))
+		}
 		if !cfg.Symbols {
 			ldflags = append(ldflags, "-s")
 		}

gen.go

@@ -78,7 +78,7 @@ func genPkg(mode bind.BuildMode, cfg *BuildCfg) error {
 	if err != nil {
 		return err
 	}
-	err = bind.GenPyBind(mode, libExt, extraGccArgs, pyvers, &cfg.BindCfg)
+	err = bind.GenPyBind(mode, libExt, extraGccArgs, pyvers, cfg.DynamicLinking, &cfg.BindCfg)
 	if err != nil {
 		log.Println(err)
 	}

go.mod

@@ -10,7 +10,7 @@ require (
 )
 
 require (
-	golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3 // indirect
+	golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 // indirect
 	golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 // indirect
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 )

go.sum

@@ -4,8 +4,8 @@ github.com/gonuts/flag v0.1.0 h1:fqMv/MZ+oNGu0i9gp0/IQ/ZaPIDoAZBOBaJoV7viCWM=
 github.com/gonuts/flag v0.1.0/go.mod h1:ZTmTGtrSPejTo/SRNhCqwLTmiAgyBdCkLYhHrAoBdz4=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3 h1:kQgndtyPBW/JIYERgdxfwMYh3AVStj88WQTlNDi2a+o=
-golang.org/x/mod v0.6.0-dev.0.20220106191415-9b9b3d81d5e3/go.mod h1:3p9vT2HGsQu2K1YbXdKPJLVgG5VJdoTa1poYQBtP1AY=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4 h1:6zppjxzCulZykYSLyVDYbneBfbaBIQPYMevg0bEwv2s=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 h1:id054HUawV2/6IGm2IV8KZQjqtwAOo2CYlOToYqa0d0=
 golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/tools v0.1.11-0.20220413170336-afc6aad76eb1 h1:Z3vE1sGlC7qiyFJkkDcZms8Y3+yV8+W7HmDSmuf71tM=

main.go

@@ -28,6 +28,8 @@ type BuildCfg struct {
 	NoWarn bool
 	// do not generate a Makefile, e.g., when called from Makefile
 	NoMake bool
+	// link resulting library dynamically
+	DynamicLinking bool
 }
 
 // NewBuildCfg returns a newly constructed build config