diff --git a/dexpreopt/config.go b/dexpreopt/config.go
index e353878..2ba6bb4 100644
--- a/dexpreopt/config.go
+++ b/dexpreopt/config.go
@@ -22,8 +22,7 @@
 )
 
 // GlobalConfig stores the configuration for dex preopting. The fields are set
-// from product variables via dex_preopt_config.mk, except for SoongConfig
-// which come from CreateGlobalSoongConfig.
+// from product variables via dex_preopt_config.mk.
 type GlobalConfig struct {
 	DisablePreopt        bool     // disable preopt for all modules
 	DisablePreoptModules []string // modules with preopt disabled by product-specific config
@@ -81,8 +80,6 @@
 	BootFlags         string               // extra flags to pass to dex2oat for the boot image
 	Dex2oatImageXmx   string               // max heap size for dex2oat for the boot image
 	Dex2oatImageXms   string               // initial heap size for dex2oat for the boot image
-
-	SoongConfig GlobalSoongConfig // settings read from dexpreopt_soong.config
 }
 
 // GlobalSoongConfig contains the global config that is generated from Soong,
@@ -179,11 +176,9 @@
 }
 
 // LoadGlobalConfig reads the global dexpreopt.config file into a GlobalConfig
-// struct, except the SoongConfig field which is set from the provided
-// soongConfig argument. LoadGlobalConfig is used directly in Soong and in
-// dexpreopt_gen called from Make to read the $OUT/dexpreopt.config written by
-// Make.
-func LoadGlobalConfig(ctx android.PathContext, data []byte, soongConfig GlobalSoongConfig) (GlobalConfig, error) {
+// struct. LoadGlobalConfig is used directly in Soong and in dexpreopt_gen
+// called from Make to read the $OUT/dexpreopt.config written by Make.
+func LoadGlobalConfig(ctx android.PathContext, data []byte) (GlobalConfig, error) {
 	type GlobalJSONConfig struct {
 		GlobalConfig
 
@@ -203,10 +198,6 @@
 	config.GlobalConfig.DirtyImageObjects = android.OptionalPathForPath(constructPath(ctx, config.DirtyImageObjects))
 	config.GlobalConfig.BootImageProfiles = constructPaths(ctx, config.BootImageProfiles)
 
-	// Set this here to force the caller to provide a value for this struct (from
-	// either CreateGlobalSoongConfig or LoadGlobalSoongConfig).
-	config.GlobalConfig.SoongConfig = soongConfig
-
 	return config.GlobalConfig, nil
 }
 
@@ -252,9 +243,16 @@
 	return config.ModuleConfig, nil
 }
 
-// CreateGlobalSoongConfig creates a GlobalSoongConfig from the current context.
+// createGlobalSoongConfig creates a GlobalSoongConfig from the current context.
 // Should not be used in dexpreopt_gen.
-func CreateGlobalSoongConfig(ctx android.PathContext) GlobalSoongConfig {
+func createGlobalSoongConfig(ctx android.ModuleContext) GlobalSoongConfig {
+	if ctx.Config().TestProductVariables != nil {
+		// If we're called in a test there'll be a confusing error from the path
+		// functions below that gets reported without a stack trace, so let's panic
+		// properly with a more helpful message.
+		panic("This should not be called from tests. Please call GlobalSoongConfigForTests somewhere in the test setup.")
+	}
+
 	// Default to debug version to help find bugs.
 	// Set USE_DEX2OAT_DEBUG to false for only building non-debug versions.
 	var dex2oatBinary string
@@ -275,6 +273,26 @@
 	}
 }
 
+var globalSoongConfigOnceKey = android.NewOnceKey("DexpreoptGlobalSoongConfig")
+
+// GetGlobalSoongConfig creates a GlobalSoongConfig the first time it's called,
+// and later returns the same cached instance.
+func GetGlobalSoongConfig(ctx android.ModuleContext) GlobalSoongConfig {
+	globalSoong := ctx.Config().Once(globalSoongConfigOnceKey, func() interface{} {
+		return createGlobalSoongConfig(ctx)
+	}).(GlobalSoongConfig)
+	return globalSoong
+}
+
+// GetCachedGlobalSoongConfig returns a cached GlobalSoongConfig created by an
+// earlier GetGlobalSoongConfig call. This function works with any context
+// compatible with a basic PathContext, since it doesn't try to create a
+// GlobalSoongConfig (which requires a full ModuleContext). It will panic if
+// called before the first GetGlobalSoongConfig call.
+func GetCachedGlobalSoongConfig(ctx android.PathContext) GlobalSoongConfig {
+	return ctx.Config().Get(globalSoongConfigOnceKey).(GlobalSoongConfig)
+}
+
 type globalJsonSoongConfig struct {
 	Profman          string
 	Dex2oat          string
@@ -309,7 +327,7 @@
 }
 
 func (s *globalSoongConfigSingleton) GenerateBuildActions(ctx android.SingletonContext) {
-	config := CreateGlobalSoongConfig(ctx)
+	config := GetCachedGlobalSoongConfig(ctx)
 	jc := globalJsonSoongConfig{
 		Profman:          config.Profman.String(),
 		Dex2oat:          config.Dex2oat.String(),
@@ -336,7 +354,7 @@
 }
 
 func (s *globalSoongConfigSingleton) MakeVars(ctx android.MakeVarsContext) {
-	config := CreateGlobalSoongConfig(ctx)
+	config := GetCachedGlobalSoongConfig(ctx)
 
 	ctx.Strict("DEX2OAT", config.Dex2oat.String())
 	ctx.Strict("DEXPREOPT_GEN_DEPS", strings.Join([]string{
@@ -389,7 +407,14 @@
 		BootFlags:                          "",
 		Dex2oatImageXmx:                    "",
 		Dex2oatImageXms:                    "",
-		SoongConfig: GlobalSoongConfig{
+	}
+}
+
+func GlobalSoongConfigForTests(config android.Config) GlobalSoongConfig {
+	// Install the test GlobalSoongConfig in the Once cache so that later calls to
+	// Get(Cached)GlobalSoongConfig returns it without trying to create a real one.
+	return config.Once(globalSoongConfigOnceKey, func() interface{} {
+		return GlobalSoongConfig{
 			Profman:          android.PathForTesting("profman"),
 			Dex2oat:          android.PathForTesting("dex2oat"),
 			Aapt:             android.PathForTesting("aapt"),
@@ -397,6 +422,6 @@
 			Zip2zip:          android.PathForTesting("zip2zip"),
 			ManifestCheck:    android.PathForTesting("manifest_check"),
 			ConstructContext: android.PathForTesting("construct_context.sh"),
-		},
-	}
+		}
+	}).(GlobalSoongConfig)
 }
diff --git a/dexpreopt/dexpreopt.go b/dexpreopt/dexpreopt.go
index 4d8ccb5..dbf08f2 100644
--- a/dexpreopt/dexpreopt.go
+++ b/dexpreopt/dexpreopt.go
@@ -58,7 +58,7 @@
 
 // GenerateDexpreoptRule generates a set of commands that will preopt a module based on a GlobalConfig and a
 // ModuleConfig.  The produced files and their install locations will be available through rule.Installs().
-func GenerateDexpreoptRule(ctx android.PathContext,
+func GenerateDexpreoptRule(ctx android.PathContext, globalSoong GlobalSoongConfig,
 	global GlobalConfig, module ModuleConfig) (rule *android.RuleBuilder, err error) {
 
 	defer func() {
@@ -81,10 +81,10 @@
 
 	var profile android.WritablePath
 	if generateProfile {
-		profile = profileCommand(ctx, global, module, rule)
+		profile = profileCommand(ctx, globalSoong, global, module, rule)
 	}
 	if generateBootProfile {
-		bootProfileCommand(ctx, global, module, rule)
+		bootProfileCommand(ctx, globalSoong, global, module, rule)
 	}
 
 	if !dexpreoptDisabled(ctx, global, module) {
@@ -96,7 +96,7 @@
 			generateDM := shouldGenerateDM(module, global)
 
 			for archIdx, _ := range module.Archs {
-				dexpreoptCommand(ctx, global, module, rule, archIdx, profile, appImage, generateDM)
+				dexpreoptCommand(ctx, globalSoong, global, module, rule, archIdx, profile, appImage, generateDM)
 			}
 		}
 	}
@@ -135,8 +135,8 @@
 	return false
 }
 
-func profileCommand(ctx android.PathContext, global GlobalConfig, module ModuleConfig,
-	rule *android.RuleBuilder) android.WritablePath {
+func profileCommand(ctx android.PathContext, globalSoong GlobalSoongConfig, global GlobalConfig,
+	module ModuleConfig, rule *android.RuleBuilder) android.WritablePath {
 
 	profilePath := module.BuildPath.InSameDir(ctx, "profile.prof")
 	profileInstalledPath := module.DexLocation + ".prof"
@@ -147,7 +147,7 @@
 
 	cmd := rule.Command().
 		Text(`ANDROID_LOG_TAGS="*:e"`).
-		Tool(global.SoongConfig.Profman)
+		Tool(globalSoong.Profman)
 
 	if module.ProfileIsTextListing {
 		// The profile is a test listing of classes (used for framework jars).
@@ -174,8 +174,8 @@
 	return profilePath
 }
 
-func bootProfileCommand(ctx android.PathContext, global GlobalConfig, module ModuleConfig,
-	rule *android.RuleBuilder) android.WritablePath {
+func bootProfileCommand(ctx android.PathContext, globalSoong GlobalSoongConfig, global GlobalConfig,
+	module ModuleConfig, rule *android.RuleBuilder) android.WritablePath {
 
 	profilePath := module.BuildPath.InSameDir(ctx, "profile.bprof")
 	profileInstalledPath := module.DexLocation + ".bprof"
@@ -186,7 +186,7 @@
 
 	cmd := rule.Command().
 		Text(`ANDROID_LOG_TAGS="*:e"`).
-		Tool(global.SoongConfig.Profman)
+		Tool(globalSoong.Profman)
 
 	// The profile is a test listing of methods.
 	// We need to generate the actual binary profile.
@@ -206,8 +206,9 @@
 	return profilePath
 }
 
-func dexpreoptCommand(ctx android.PathContext, global GlobalConfig, module ModuleConfig, rule *android.RuleBuilder,
-	archIdx int, profile android.WritablePath, appImage bool, generateDM bool) {
+func dexpreoptCommand(ctx android.PathContext, globalSoong GlobalSoongConfig, global GlobalConfig,
+	module ModuleConfig, rule *android.RuleBuilder, archIdx int, profile android.WritablePath,
+	appImage bool, generateDM bool) {
 
 	arch := module.Archs[archIdx]
 
@@ -345,14 +346,14 @@
 	if module.EnforceUsesLibraries {
 		if module.ManifestPath != nil {
 			rule.Command().Text(`target_sdk_version="$(`).
-				Tool(global.SoongConfig.ManifestCheck).
+				Tool(globalSoong.ManifestCheck).
 				Flag("--extract-target-sdk-version").
 				Input(module.ManifestPath).
 				Text(`)"`)
 		} else {
 			// No manifest to extract targetSdkVersion from, hope that DexJar is an APK
 			rule.Command().Text(`target_sdk_version="$(`).
-				Tool(global.SoongConfig.Aapt).
+				Tool(globalSoong.Aapt).
 				Flag("dump badging").
 				Input(module.DexPath).
 				Text(`| grep "targetSdkVersion" | sed -n "s/targetSdkVersion:'\(.*\)'/\1/p"`).
@@ -373,7 +374,7 @@
 			Implicits(conditionalClassLoaderContextHost29)
 		rule.Command().Textf(`conditional_target_libs_29="%s"`,
 			strings.Join(conditionalClassLoaderContextTarget29, " "))
-		rule.Command().Text("source").Tool(global.SoongConfig.ConstructContext).Input(module.DexPath)
+		rule.Command().Text("source").Tool(globalSoong.ConstructContext).Input(module.DexPath)
 	}
 
 	// Devices that do not have a product partition use a symlink from /product to /system/product.
@@ -386,7 +387,7 @@
 
 	cmd := rule.Command().
 		Text(`ANDROID_LOG_TAGS="*:e"`).
-		Tool(global.SoongConfig.Dex2oat).
+		Tool(globalSoong.Dex2oat).
 		Flag("--avoid-storing-invocation").
 		FlagWithOutput("--write-invocation-to=", invocationPath).ImplicitOutput(invocationPath).
 		Flag("--runtime-arg").FlagWithArg("-Xms", global.Dex2oatXms).
@@ -455,7 +456,7 @@
 		dmInstalledPath := pathtools.ReplaceExtension(module.DexLocation, "dm")
 		tmpPath := module.BuildPath.InSameDir(ctx, "primary.vdex")
 		rule.Command().Text("cp -f").Input(vdexPath).Output(tmpPath)
-		rule.Command().Tool(global.SoongConfig.SoongZip).
+		rule.Command().Tool(globalSoong.SoongZip).
 			FlagWithArg("-L", "9").
 			FlagWithOutput("-o", dmPath).
 			Flag("-j").
diff --git a/dexpreopt/dexpreopt_gen/dexpreopt_gen.go b/dexpreopt/dexpreopt_gen/dexpreopt_gen.go
index e2818bb..708bb9b 100644
--- a/dexpreopt/dexpreopt_gen/dexpreopt_gen.go
+++ b/dexpreopt/dexpreopt_gen/dexpreopt_gen.go
@@ -80,13 +80,13 @@
 
 	globalSoongConfigData, err := ioutil.ReadFile(*globalSoongConfigPath)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "error reading global config %q: %s\n", *globalSoongConfigPath, err)
+		fmt.Fprintf(os.Stderr, "error reading global Soong config %q: %s\n", *globalSoongConfigPath, err)
 		os.Exit(2)
 	}
 
 	globalSoongConfig, err := dexpreopt.LoadGlobalSoongConfig(ctx, globalSoongConfigData)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "error loading global config %q: %s\n", *globalSoongConfigPath, err)
+		fmt.Fprintf(os.Stderr, "error loading global Soong config %q: %s\n", *globalSoongConfigPath, err)
 		os.Exit(2)
 	}
 
@@ -96,9 +96,9 @@
 		os.Exit(2)
 	}
 
-	globalConfig, err := dexpreopt.LoadGlobalConfig(ctx, globalConfigData, globalSoongConfig)
+	globalConfig, err := dexpreopt.LoadGlobalConfig(ctx, globalConfigData)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "error parse global config %q: %s\n", *globalConfigPath, err)
+		fmt.Fprintf(os.Stderr, "error loading global config %q: %s\n", *globalConfigPath, err)
 		os.Exit(2)
 	}
 
@@ -130,12 +130,12 @@
 		}
 	}()
 
-	writeScripts(ctx, globalConfig, moduleConfig, *dexpreoptScriptPath)
+	writeScripts(ctx, globalSoongConfig, globalConfig, moduleConfig, *dexpreoptScriptPath)
 }
 
-func writeScripts(ctx android.PathContext, global dexpreopt.GlobalConfig, module dexpreopt.ModuleConfig,
-	dexpreoptScriptPath string) {
-	dexpreoptRule, err := dexpreopt.GenerateDexpreoptRule(ctx, global, module)
+func writeScripts(ctx android.PathContext, globalSoong dexpreopt.GlobalSoongConfig,
+	global dexpreopt.GlobalConfig, module dexpreopt.ModuleConfig, dexpreoptScriptPath string) {
+	dexpreoptRule, err := dexpreopt.GenerateDexpreoptRule(ctx, globalSoong, global, module)
 	if err != nil {
 		panic(err)
 	}
@@ -150,7 +150,7 @@
 		dexpreoptRule.Command().Text("mkdir -p").Flag(filepath.Dir(installPath.String()))
 		dexpreoptRule.Command().Text("cp -f").Input(install.From).Output(installPath)
 	}
-	dexpreoptRule.Command().Tool(global.SoongConfig.SoongZip).
+	dexpreoptRule.Command().Tool(globalSoong.SoongZip).
 		FlagWithArg("-o ", "$2").
 		FlagWithArg("-C ", installDir.String()).
 		FlagWithArg("-D ", installDir.String())
diff --git a/dexpreopt/dexpreopt_test.go b/dexpreopt/dexpreopt_test.go
index a128dc0..44bbbc2 100644
--- a/dexpreopt/dexpreopt_test.go
+++ b/dexpreopt/dexpreopt_test.go
@@ -61,10 +61,13 @@
 }
 
 func TestDexPreopt(t *testing.T) {
-	ctx := android.PathContextForTesting(android.TestConfig("out", nil, "", nil))
-	global, module := GlobalConfigForTests(ctx), testSystemModuleConfig(ctx, "test")
+	config := android.TestConfig("out", nil, "", nil)
+	ctx := android.PathContextForTesting(config)
+	globalSoong := GlobalSoongConfigForTests(config)
+	global := GlobalConfigForTests(ctx)
+	module := testSystemModuleConfig(ctx, "test")
 
-	rule, err := GenerateDexpreoptRule(ctx, global, module)
+	rule, err := GenerateDexpreoptRule(ctx, globalSoong, global, module)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -80,7 +83,9 @@
 }
 
 func TestDexPreoptSystemOther(t *testing.T) {
-	ctx := android.PathContextForTesting(android.TestConfig("out", nil, "", nil))
+	config := android.TestConfig("out", nil, "", nil)
+	ctx := android.PathContextForTesting(config)
+	globalSoong := GlobalSoongConfigForTests(config)
 	global := GlobalConfigForTests(ctx)
 	systemModule := testSystemModuleConfig(ctx, "Stest")
 	systemProductModule := testSystemProductModuleConfig(ctx, "SPtest")
@@ -118,7 +123,7 @@
 	for _, test := range tests {
 		global.PatternsOnSystemOther = test.patterns
 		for _, mt := range test.moduleTests {
-			rule, err := GenerateDexpreoptRule(ctx, global, mt.module)
+			rule, err := GenerateDexpreoptRule(ctx, globalSoong, global, mt.module)
 			if err != nil {
 				t.Fatal(err)
 			}
@@ -138,12 +143,15 @@
 }
 
 func TestDexPreoptProfile(t *testing.T) {
-	ctx := android.PathContextForTesting(android.TestConfig("out", nil, "", nil))
-	global, module := GlobalConfigForTests(ctx), testSystemModuleConfig(ctx, "test")
+	config := android.TestConfig("out", nil, "", nil)
+	ctx := android.PathContextForTesting(config)
+	globalSoong := GlobalSoongConfigForTests(config)
+	global := GlobalConfigForTests(ctx)
+	module := testSystemModuleConfig(ctx, "test")
 
 	module.ProfileClassListing = android.OptionalPathForPath(android.PathForTesting("profile"))
 
-	rule, err := GenerateDexpreoptRule(ctx, global, module)
+	rule, err := GenerateDexpreoptRule(ctx, globalSoong, global, module)
 	if err != nil {
 		t.Fatal(err)
 	}