diff --git a/cc/builder.go b/cc/builder.go
index 372c531..142a326 100644
--- a/cc/builder.go
+++ b/cc/builder.go
@@ -197,10 +197,10 @@
 	_ = pctx.SourcePathVariable("sAbiDiffer", "prebuilts/clang-tools/${config.HostPrebuiltTag}/bin/header-abi-diff")
 
 	sAbiDiff = pctx.AndroidRuleFunc("sAbiDiff",
-		func(config android.Config) (blueprint.RuleParams, error) {
+		func(ctx android.PackageRuleContext) blueprint.RuleParams {
 
 			commandStr := "($sAbiDiffer $allowFlags -lib $libName -arch $arch -check-all-apis -o ${out} -new $in -old $referenceDump)"
-			distDir := config.ProductVariables.DistDir
+			distDir := ctx.Config().ProductVariables.DistDir
 			if distDir != nil && *distDir != "" {
 				distAbiDiffDir := *distDir + "/abidiffs/"
 				commandStr += "  || (mkdir -p " + distAbiDiffDir + " && cp ${out} " + distAbiDiffDir + " && exit 1)"
@@ -208,7 +208,7 @@
 			return blueprint.RuleParams{
 				Command:     commandStr,
 				CommandDeps: []string{"$sAbiDiffer"},
-			}, nil
+			}
 		},
 		"allowFlags", "referenceDump", "libName", "arch")
 
diff --git a/cc/config/global.go b/cc/config/global.go
index 528db36..359ea8c 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -180,26 +180,26 @@
 		[]string{"libnativehelper/include_deprecated"})
 
 	pctx.SourcePathVariable("ClangDefaultBase", ClangDefaultBase)
-	pctx.VariableFunc("ClangBase", func(config android.Config) (string, error) {
-		if override := config.Getenv("LLVM_PREBUILTS_BASE"); override != "" {
-			return override, nil
+	pctx.VariableFunc("ClangBase", func(ctx android.PackageVarContext) string {
+		if override := ctx.Config().Getenv("LLVM_PREBUILTS_BASE"); override != "" {
+			return override
 		}
-		return "${ClangDefaultBase}", nil
+		return "${ClangDefaultBase}"
 	})
-	pctx.VariableFunc("ClangVersion", func(config android.Config) (string, error) {
-		if override := config.Getenv("LLVM_PREBUILTS_VERSION"); override != "" {
-			return override, nil
+	pctx.VariableFunc("ClangVersion", func(ctx android.PackageVarContext) string {
+		if override := ctx.Config().Getenv("LLVM_PREBUILTS_VERSION"); override != "" {
+			return override
 		}
-		return ClangDefaultVersion, nil
+		return ClangDefaultVersion
 	})
 	pctx.StaticVariable("ClangPath", "${ClangBase}/${HostPrebuiltTag}/${ClangVersion}")
 	pctx.StaticVariable("ClangBin", "${ClangPath}/bin")
 
-	pctx.VariableFunc("ClangShortVersion", func(config android.Config) (string, error) {
-		if override := config.Getenv("LLVM_RELEASE_VERSION"); override != "" {
-			return override, nil
+	pctx.VariableFunc("ClangShortVersion", func(ctx android.PackageVarContext) string {
+		if override := ctx.Config().Getenv("LLVM_RELEASE_VERSION"); override != "" {
+			return override
 		}
-		return ClangDefaultShortVersion, nil
+		return ClangDefaultShortVersion
 	})
 	pctx.StaticVariable("ClangAsanLibDir", "${ClangBase}/linux-x86/${ClangVersion}/lib64/clang/${ClangShortVersion}/lib/linux")
 	if runtime.GOOS == "darwin" {
@@ -222,11 +222,11 @@
 			"frameworks/rs/script_api/include",
 		})
 
-	pctx.VariableFunc("CcWrapper", func(config android.Config) (string, error) {
-		if override := config.Getenv("CC_WRAPPER"); override != "" {
-			return override + " ", nil
+	pctx.VariableFunc("CcWrapper", func(ctx android.PackageVarContext) string {
+		if override := ctx.Config().Getenv("CC_WRAPPER"); override != "" {
+			return override + " "
 		}
-		return "", nil
+		return ""
 	})
 }
 
diff --git a/cc/config/tidy.go b/cc/config/tidy.go
index 76a5f9e..a20d556 100644
--- a/cc/config/tidy.go
+++ b/cc/config/tidy.go
@@ -15,9 +15,8 @@
 package config
 
 import (
-	"strings"
-
 	"android/soong/android"
+	"strings"
 )
 
 func init() {
@@ -25,9 +24,9 @@
 	// Global tidy checks include only google*, performance*,
 	// and misc-macro-parentheses, but not google-readability*
 	// or google-runtime-references.
-	pctx.VariableFunc("TidyDefaultGlobalChecks", func(config android.Config) (string, error) {
-		if override := config.Getenv("DEFAULT_GLOBAL_TIDY_CHECKS"); override != "" {
-			return override, nil
+	pctx.VariableFunc("TidyDefaultGlobalChecks", func(ctx android.PackageVarContext) string {
+		if override := ctx.Config().Getenv("DEFAULT_GLOBAL_TIDY_CHECKS"); override != "" {
+			return override
 		}
 		return strings.Join([]string{
 			"-*",
@@ -36,14 +35,14 @@
 			"performance*",
 			"-google-readability*",
 			"-google-runtime-references",
-		}, ","), nil
+		}, ",")
 	})
 
 	// There are too many clang-tidy warnings in external and vendor projects.
 	// Enable only some google checks for these projects.
-	pctx.VariableFunc("TidyExternalVendorChecks", func(config android.Config) (string, error) {
-		if override := config.Getenv("DEFAULT_EXTERNAL_VENDOR_TIDY_CHECKS"); override != "" {
-			return override, nil
+	pctx.VariableFunc("TidyExternalVendorChecks", func(ctx android.PackageVarContext) string {
+		if override := ctx.Config().Getenv("DEFAULT_EXTERNAL_VENDOR_TIDY_CHECKS"); override != "" {
+			return override
 		}
 		return strings.Join([]string{
 			"-*",
@@ -54,7 +53,7 @@
 			"-google-readability*",
 			"-google-runtime-int",
 			"-google-runtime-references",
-		}, ","), nil
+		}, ",")
 	})
 
 	// Give warnings to header files only in selected directories.
diff --git a/cc/config/x86_darwin_host.go b/cc/config/x86_darwin_host.go
index dbaa6fa..cae9757 100644
--- a/cc/config/x86_darwin_host.go
+++ b/cc/config/x86_darwin_host.go
@@ -15,7 +15,6 @@
 package config
 
 import (
-	"fmt"
 	"os/exec"
 	"path/filepath"
 	"strings"
@@ -107,26 +106,28 @@
 )
 
 func init() {
-	pctx.VariableFunc("macSdkPath", func(config android.Config) (string, error) {
-		xcodeselect := config.HostSystemTool("xcode-select")
+	pctx.VariableFunc("macSdkPath", func(ctx android.PackageVarContext) string {
+		xcodeselect := ctx.Config().HostSystemTool("xcode-select")
 		bytes, err := exec.Command(xcodeselect, "--print-path").Output()
-		return strings.TrimSpace(string(bytes)), err
+		if err != nil {
+			ctx.Errorf("xcode-select failed with: %q", err.Error())
+		}
+		return strings.TrimSpace(string(bytes))
 	})
-	pctx.VariableFunc("macSdkRoot", func(config android.Config) (string, error) {
-		return xcrunSdk(config, "--show-sdk-path")
+	pctx.VariableFunc("macSdkRoot", func(ctx android.PackageVarContext) string {
+		return xcrunSdk(ctx, "--show-sdk-path")
 	})
 	pctx.StaticVariable("macMinVersion", "10.8")
-	pctx.VariableFunc("MacArPath", func(config android.Config) (string, error) {
-		return xcrun(config, "--find", "ar")
+	pctx.VariableFunc("MacArPath", func(ctx android.PackageVarContext) string {
+		return xcrun(ctx, "--find", "ar")
 	})
 
-	pctx.VariableFunc("MacStripPath", func(config android.Config) (string, error) {
-		return xcrun(config, "--find", "strip")
+	pctx.VariableFunc("MacStripPath", func(ctx android.PackageVarContext) string {
+		return xcrun(ctx, "--find", "strip")
 	})
 
-	pctx.VariableFunc("MacToolPath", func(config android.Config) (string, error) {
-		path, err := xcrun(config, "--find", "ld")
-		return filepath.Dir(path), err
+	pctx.VariableFunc("MacToolPath", func(ctx android.PackageVarContext) string {
+		return filepath.Dir(xcrun(ctx, "--find", "ld"))
 	})
 
 	pctx.StaticVariable("DarwinGccVersion", darwinGccVersion)
@@ -156,33 +157,38 @@
 	pctx.StaticVariable("DarwinX8664YasmFlags", "-f macho -m amd64")
 }
 
-func xcrun(config android.Config, args ...string) (string, error) {
-	xcrun := config.HostSystemTool("xcrun")
+func xcrun(ctx android.PackageVarContext, args ...string) string {
+	xcrun := ctx.Config().HostSystemTool("xcrun")
 	bytes, err := exec.Command(xcrun, args...).Output()
-	return strings.TrimSpace(string(bytes)), err
+	if err != nil {
+		ctx.Errorf("xcrun failed with: %q", err.Error())
+	}
+	return strings.TrimSpace(string(bytes))
 }
 
-func xcrunSdk(config android.Config, arg string) (string, error) {
-	xcrun := config.HostSystemTool("xcrun")
-	if selected := config.Getenv("MAC_SDK_VERSION"); selected != "" {
+func xcrunSdk(ctx android.PackageVarContext, arg string) string {
+	xcrun := ctx.Config().HostSystemTool("xcrun")
+	if selected := ctx.Config().Getenv("MAC_SDK_VERSION"); selected != "" {
 		if !inList(selected, darwinSupportedSdkVersions) {
-			return "", fmt.Errorf("MAC_SDK_VERSION %s isn't supported: %q", selected, darwinSupportedSdkVersions)
+			ctx.Errorf("MAC_SDK_VERSION %s isn't supported: %q", selected, darwinSupportedSdkVersions)
+			return ""
 		}
 
 		bytes, err := exec.Command(xcrun, "--sdk", "macosx"+selected, arg).Output()
-		if err == nil {
-			return strings.TrimSpace(string(bytes)), err
+		if err != nil {
+			ctx.Errorf("MAC_SDK_VERSION %s is not installed", selected)
 		}
-		return "", fmt.Errorf("MAC_SDK_VERSION %s is not installed", selected)
+		return strings.TrimSpace(string(bytes))
 	}
 
 	for _, sdk := range darwinSupportedSdkVersions {
 		bytes, err := exec.Command(xcrun, "--sdk", "macosx"+sdk, arg).Output()
 		if err == nil {
-			return strings.TrimSpace(string(bytes)), err
+			return strings.TrimSpace(string(bytes))
 		}
 	}
-	return "", fmt.Errorf("Could not find a supported mac sdk: %q", darwinSupportedSdkVersions)
+	ctx.Errorf("Could not find a supported mac sdk: %q", darwinSupportedSdkVersions)
+	return ""
 }
 
 type toolchainDarwin struct {