convert hidden visibility flag to feature

in bp2build. The context here is that `-fvisibility=default` should
only be added for CFI if `-fvisibility=hidden` is not already
specified. This will be achieved using toolchain features. Note
that Soong itself never adds `-fvisibility=hidden`. This is only
ever added in the `cflags` property of a bp file.

Bug: 261733820
Test: Unit tests
Change-Id: Ib821e8c30a9cd03d2929b4bd2e771bec7b33fa66
diff --git a/cc/library.go b/cc/library.go
index 172ca64..1daeeff 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -311,6 +311,11 @@
 		asFlags = bazel.MakeStringListAttribute(nil)
 	}
 
+	sharedFeatures := baseAttributes.features.Clone().Append(sharedAttrs.Features)
+	sharedFeatures.DeduplicateAxesFromBase()
+	staticFeatures := baseAttributes.features.Clone().Append(staticAttrs.Features)
+	staticFeatures.DeduplicateAxesFromBase()
+
 	staticCommonAttrs := staticOrSharedAttributes{
 		Srcs:    *srcs.Clone().Append(staticAttrs.Srcs),
 		Srcs_c:  *compilerAttrs.cSrcs.Clone().Append(staticAttrs.Srcs_c),
@@ -366,7 +371,7 @@
 		Cpp_std:                  compilerAttrs.cppStd,
 		C_std:                    compilerAttrs.cStd,
 
-		Features: baseAttributes.features,
+		Features: *staticFeatures,
 	}
 
 	sharedTargetAttrs := &bazelCcLibrarySharedAttributes{
@@ -390,7 +395,7 @@
 		Additional_linker_inputs: linkerAttrs.additionalLinkerInputs,
 
 		Strip:                             stripAttrsFromLinkerAttrs(&linkerAttrs),
-		Features:                          baseAttributes.features,
+		Features:                          *sharedFeatures,
 		bazelCcHeaderAbiCheckerAttributes: bp2buildParseAbiCheckerProps(ctx, m),
 
 		Fdo_profile: compilerAttrs.fdoProfile,
@@ -2881,6 +2886,9 @@
 		asFlags = bazel.MakeStringListAttribute(nil)
 	}
 
+	features := baseAttributes.features.Clone().Append(libSharedOrStaticAttrs.Features)
+	features.DeduplicateAxesFromBase()
+
 	commonAttrs := staticOrSharedAttributes{
 		Srcs:    compilerAttrs.srcs,
 		Srcs_c:  compilerAttrs.cSrcs,
@@ -2922,7 +2930,7 @@
 			Conlyflags: compilerAttrs.conlyFlags,
 			Asflags:    asFlags,
 
-			Features: baseAttributes.features,
+			Features: *features,
 		}
 	} else {
 		commonAttrs.Dynamic_deps.Add(baseAttributes.protoDependency)
@@ -2951,7 +2959,7 @@
 
 			Strip: stripAttrsFromLinkerAttrs(&linkerAttrs),
 
-			Features: baseAttributes.features,
+			Features: *features,
 
 			Suffix: compilerAttrs.suffix,