Support empty srcs for configurable attrs

Test: mixed build linkerconfig
Change-Id: I1ee56f7fa46ce2971ecae6d2ca9258631a32f46a

bazel/properties.go

@@ -140,7 +140,6 @@ func SubtractStrings(haystack []string, needle []string) []string {
 // Return all needles in a given haystack, where needleFn is true for needles.
 func FilterLabelList(haystack LabelList, needleFn func(string) bool) LabelList {
 	var includes []Label
-
 	for _, inc := range haystack.Includes {
 		if needleFn(inc.Label) {
 			includes = append(includes, inc)

bp2build/build_conversion.go

@@ -445,7 +445,7 @@ func prettyPrint(propertyValue reflect.Value, indent int) (string, error) {
 		return prettyPrint(propertyValue.Elem(), indent)
 	case reflect.Slice:
 		if propertyValue.Len() == 0 {
-			return "", nil
+			return "[]", nil
 		}
 
 		if propertyValue.Len() == 1 {

bp2build/cc_library_static_conversion_test.go

@@ -850,6 +850,84 @@ cc_library_static {
 	})
 }
 
+func TestCcLibraryStaticOneArchEmpty(t *testing.T) {
+	runCcLibraryStaticTestCase(t, bp2buildTestCase{
+		description:                        "cc_library_static one arch empty",
+		moduleTypeUnderTest:                "cc_library_static",
+		moduleTypeUnderTestFactory:         cc.LibraryStaticFactory,
+		moduleTypeUnderTestBp2BuildMutator: cc.CcLibraryStaticBp2Build,
+		depsMutators:                       []android.RegisterMutatorFunc{cc.RegisterDepsBp2Build},
+		filesystem: map[string]string{
+			"common.cc":       "",
+			"foo-no-arm.cc":   "",
+			"foo-excluded.cc": "",
+		},
+		blueprint: soongCcLibraryStaticPreamble + `
+cc_library_static {
+    name: "foo_static",
+    srcs: ["common.cc", "foo-*.cc"],
+    exclude_srcs: ["foo-excluded.cc"],
+    arch: {
+        arm: { exclude_srcs: ["foo-no-arm.cc"] },
+    },
+}`,
+		expectedBazelTargets: []string{`cc_library_static(
+    name = "foo_static",
+    copts = [
+        "-I.",
+        "-I$(BINDIR)/.",
+    ],
+    linkstatic = True,
+    srcs = ["common.cc"] + select({
+        "//build/bazel/platforms/arch:arm": [],
+        "//conditions:default": ["foo-no-arm.cc"],
+    }),
+)`},
+	})
+}
+
+func TestCcLibraryStaticOneArchEmptyOtherSet(t *testing.T) {
+	runCcLibraryStaticTestCase(t, bp2buildTestCase{
+		description:                        "cc_library_static one arch empty other set",
+		moduleTypeUnderTest:                "cc_library_static",
+		moduleTypeUnderTestFactory:         cc.LibraryStaticFactory,
+		moduleTypeUnderTestBp2BuildMutator: cc.CcLibraryStaticBp2Build,
+		depsMutators:                       []android.RegisterMutatorFunc{cc.RegisterDepsBp2Build},
+		filesystem: map[string]string{
+			"common.cc":       "",
+			"foo-no-arm.cc":   "",
+			"x86-only.cc":     "",
+			"foo-excluded.cc": "",
+		},
+		blueprint: soongCcLibraryStaticPreamble + `
+cc_library_static {
+    name: "foo_static",
+    srcs: ["common.cc", "foo-*.cc"],
+    exclude_srcs: ["foo-excluded.cc"],
+    arch: {
+        arm: { exclude_srcs: ["foo-no-arm.cc"] },
+        x86: { srcs: ["x86-only.cc"] },
+    },
+}`,
+		expectedBazelTargets: []string{`cc_library_static(
+    name = "foo_static",
+    copts = [
+        "-I.",
+        "-I$(BINDIR)/.",
+    ],
+    linkstatic = True,
+    srcs = ["common.cc"] + select({
+        "//build/bazel/platforms/arch:arm": [],
+        "//build/bazel/platforms/arch:x86": [
+            "foo-no-arm.cc",
+            "x86-only.cc",
+        ],
+        "//conditions:default": ["foo-no-arm.cc"],
+    }),
+)`},
+	})
+}
+
 func TestCcLibraryStaticMultipleDepSameName(t *testing.T) {
 	runCcLibraryStaticTestCase(t, bp2buildTestCase{
 		description:                        "cc_library_static multiple dep same name panic",

bp2build/configurability.go

@@ -80,32 +80,55 @@ func getLabelListValues(list bazel.LabelListAttribute) (reflect.Value, []selects
 	if !list.HasConfigurableValues() {
 		return value, []selects{}
 	}
+	var ret []selects
 
 	archSelects := map[string]reflect.Value{}
 	for arch, selectKey := range bazel.PlatformArchMap {
-		archSelects[selectKey] = reflect.ValueOf(list.GetValueForArch(arch).Includes)
+		if use, value := labelListSelectValue(selectKey, list.GetValueForArch(arch)); use {
+			archSelects[selectKey] = value
+		}
+	}
+	if len(archSelects) > 0 {
+		ret = append(ret, archSelects)
 	}
 
 	osSelects := map[string]reflect.Value{}
-	osArchSelects := make([]selects, 0)
+	osArchSelects := []selects{}
 	for _, os := range android.SortedStringKeys(bazel.PlatformOsMap) {
 		selectKey := bazel.PlatformOsMap[os]
-		osSelects[selectKey] = reflect.ValueOf(list.GetOsValueForTarget(os).Includes)
+		if use, value := labelListSelectValue(selectKey, list.GetOsValueForTarget(os)); use {
-		archSelects := make(map[string]reflect.Value)
+			osSelects[selectKey] = value
+		}
+		selects := make(map[string]reflect.Value)
 		// TODO(b/187530594): Should we also check arch=CONDITIOSN_DEFAULT? (not in AllArches)
 		for _, arch := range bazel.AllArches {
 			target := os + "_" + arch
 			selectKey := bazel.PlatformTargetMap[target]
-			archSelects[selectKey] = reflect.ValueOf(list.GetOsArchValueForTarget(os, arch).Includes)
+			if use, value := labelListSelectValue(selectKey, list.GetOsArchValueForTarget(os, arch)); use {
+				selects[selectKey] = value
+			}
+		}
+		if len(selects) > 0 {
+			osArchSelects = append(osArchSelects, selects)
 		}
-		osArchSelects = append(osArchSelects, archSelects)
 	}
+	if len(osSelects) > 0 {
+		ret = append(ret, osSelects)
+	}
+	ret = append(ret, osArchSelects...)
 
-	var selects []selects
+	return value, ret
-	selects = append(selects, archSelects)
+}
-	selects = append(selects, osSelects)
+
-	selects = append(selects, osArchSelects...)
+func labelListSelectValue(selectKey string, list bazel.LabelList) (bool, reflect.Value) {
-	return value, selects
+	if selectKey == bazel.ConditionsDefaultSelectKey || len(list.Includes) > 0 {
+		return true, reflect.ValueOf(list.Includes)
+	} else if len(list.Excludes) > 0 {
+		// if there is still an excludes -- we need to have an empty list for this select & use the
+		// value in conditions default Includes
+		return true, reflect.ValueOf([]string{})
+	}
+	return false, reflect.Zero(reflect.TypeOf([]string{}))
 }
 
 // prettyPrintAttribute converts an Attribute to its Bazel syntax. May contain

cc/bp2build.go

@@ -421,7 +421,9 @@ func bp2BuildParseCompilerProps(ctx android.TopDownMutatorContext, module *Modul
 		if baseCompilerProps, ok := osProps.Properties.(*BaseCompilerProperties); ok {
 			srcsList := parseSrcs(baseCompilerProps)
 			// TODO(b/186153868): add support for os-specific srcs and exclude_srcs
-			srcs.SetOsValueForTarget(os.Name, bazel.SubtractBazelLabelList(srcsList, baseSrcsLabelList))
+			if len(baseCompilerProps.Srcs) > 0 || len(baseCompilerProps.Exclude_srcs) > 0 {
+				srcs.SetOsValueForTarget(os.Name, bazel.SubtractBazelLabelList(srcsList, baseSrcsLabelList))
+			}
 			copts.SetOsValueForTarget(os.Name, parseCopts(baseCompilerProps))
 			asFlags.SetOsValueForTarget(os.Name, parseCommandLineFlags(baseCompilerProps.Asflags))
 			conlyFlags.SetOsValueForTarget(os.Name, parseCommandLineFlags(baseCompilerProps.Conlyflags))
@@ -431,7 +433,9 @@ func bp2BuildParseCompilerProps(ctx android.TopDownMutatorContext, module *Modul
 			if baseCompilerProps, ok := archProps.(*BaseCompilerProperties); ok {
 				srcsList := parseSrcs(baseCompilerProps)
 				// TODO(b/186153868): add support for os-specific srcs and exclude_srcs
-				srcs.SetOsArchValueForTarget(os.Name, arch.Name, bazel.SubtractBazelLabelList(srcsList, baseSrcsLabelList))
+				if len(baseCompilerProps.Srcs) > 0 || len(baseCompilerProps.Exclude_srcs) > 0 {
+					srcs.SetOsArchValueForTarget(os.Name, arch.Name, bazel.SubtractBazelLabelList(srcsList, baseSrcsLabelList))
+				}
 				copts.SetOsArchValueForTarget(os.Name, arch.Name, parseCopts(baseCompilerProps))
 				asFlags.SetOsArchValueForTarget(os.Name, arch.Name, parseCommandLineFlags(baseCompilerProps.Asflags))
 				conlyFlags.SetOsArchValueForTarget(os.Name, arch.Name, parseCommandLineFlags(baseCompilerProps.Conlyflags))