Converters for contributions to systemapi and vendorapi

The module types in scope of this conversion are
1. cc_library and cc_library_shared (non-null llndk or stubs prop)
2. cc_library_headers (all)

For (2), we need some postprocessing on the results of the parser
bp2BuildParseBaseProps. This is necessary because arch and os specific
API exports need to be flattened and added to the generateed API headers
target along NoConfigAxis
e.g.
```
The api equivalent of
cc_library_headers (
  name = "lifoo",
  deps = select({
  	"//build/bazel/platforms/arch:arm": ["arm_deps"],
  	"//build/bazel/platforms/arch:arm64": ["arm64_deps"],
	}),
)
should be
cc_api_library_headers (
  name = "lifoo",
  deps = ["arm_deps", "arm64_deps"],
)
```

For (1), we also need to generate 1:many header api targets so that
arch-specific deps can propagate arch metadata to the top-level
api_domain rule

Test: go test ./bp2build
Test: go test ./cc

Change-Id: Ie40cba1ac8e89f290b3d926c190d5e93abd52859

cc/library_headers.go

@@ -15,6 +15,8 @@
 package cc
 
 import (
+	"github.com/google/blueprint/proptools"
+
 	"android/soong/android"
 	"android/soong/bazel"
 	"android/soong/bazel/cquery"
@@ -145,3 +147,118 @@ func libraryHeadersBp2Build(ctx android.TopDownMutatorContext, module *Module) {
 
 	ctx.CreateBazelTargetModule(props, android.CommonAttributes{Name: module.Name()}, attrs)
 }
+
+// Append .contribution suffix to input labels
+func apiBazelTargets(ll bazel.LabelList) bazel.LabelList {
+	labels := make([]bazel.Label, 0)
+	for _, l := range ll.Includes {
+		labels = append(labels, bazel.Label{
+			Label: android.ApiContributionTargetName(l.Label),
+		})
+	}
+	return bazel.MakeLabelList(labels)
+}
+
+func apiLibraryHeadersBp2Build(ctx android.TopDownMutatorContext, module *Module) {
+	// cc_api_library_headers have a 1:1 mapping to arch/no-arch
+	// For API export, create a top-level arch-agnostic target and list the arch-specific targets as its deps
+
+	// arch-agnostic includes
+	apiIncludes := getSystemApiIncludes(ctx, module)
+	// arch and os specific includes
+	archApiIncludes, androidOsIncludes := archOsSpecificApiIncludes(ctx, module)
+	for _, arch := range allArches { // sorted iteration
+		archApiInclude := archApiIncludes[arch]
+		if !archApiInclude.isEmpty() {
+			createApiHeaderTarget(ctx, archApiInclude)
+			apiIncludes.addDep(archApiInclude.name)
+		}
+	}
+	// os==android includes
+	if !androidOsIncludes.isEmpty() {
+		createApiHeaderTarget(ctx, androidOsIncludes)
+		apiIncludes.addDep(androidOsIncludes.name)
+	}
+
+	if !apiIncludes.isEmpty() {
+		// override the name from <mod>.systemapi.headers --> <mod>.contribution
+		apiIncludes.name = android.ApiContributionTargetName(module.Name())
+		createApiHeaderTarget(ctx, apiIncludes)
+	}
+}
+
+func createApiHeaderTarget(ctx android.TopDownMutatorContext, includes apiIncludes) {
+	props := bazel.BazelTargetModuleProperties{
+		Rule_class:        "cc_api_library_headers",
+		Bzl_load_location: "//build/bazel/rules/apis:cc_api_contribution.bzl",
+	}
+	ctx.CreateBazelTargetModule(
+		props,
+		android.CommonAttributes{
+			Name:     includes.name,
+			SkipData: proptools.BoolPtr(true),
+		},
+		&includes.attrs,
+	)
+}
+
+var (
+	allArches = []string{"arm", "arm64", "x86", "x86_64"}
+)
+
+type archApiIncludes map[string]apiIncludes
+
+func archOsSpecificApiIncludes(ctx android.TopDownMutatorContext, module *Module) (archApiIncludes, apiIncludes) {
+	baseProps := bp2BuildParseBaseProps(ctx, module)
+	i := bp2BuildParseExportedIncludes(ctx, module, &baseProps.includes)
+	archRet := archApiIncludes{}
+	for _, arch := range allArches {
+		includes := i.Includes.SelectValue(
+			bazel.ArchConfigurationAxis,
+			arch)
+		systemIncludes := i.SystemIncludes.SelectValue(
+			bazel.ArchConfigurationAxis,
+			arch)
+		deps := baseProps.deps.SelectValue(
+			bazel.ArchConfigurationAxis,
+			arch)
+		attrs := bazelCcLibraryHeadersAttributes{
+			Export_includes:        bazel.MakeStringListAttribute(includes),
+			Export_system_includes: bazel.MakeStringListAttribute(systemIncludes),
+		}
+		apiDeps := apiBazelTargets(deps)
+		if !apiDeps.IsEmpty() {
+			attrs.Deps = bazel.MakeLabelListAttribute(apiDeps)
+		}
+		apiIncludes := apiIncludes{
+			name: android.ApiContributionTargetName(module.Name()) + "." + arch,
+			attrs: bazelCcApiLibraryHeadersAttributes{
+				bazelCcLibraryHeadersAttributes: attrs,
+				Arch:                            proptools.StringPtr(arch),
+			},
+		}
+		archRet[arch] = apiIncludes
+	}
+
+	// apiIncludes for os == Android
+	androidOsDeps := baseProps.deps.SelectValue(bazel.OsConfigurationAxis, bazel.OsAndroid)
+	androidOsAttrs := bazelCcLibraryHeadersAttributes{
+		Export_includes: bazel.MakeStringListAttribute(
+			i.Includes.SelectValue(bazel.OsConfigurationAxis, bazel.OsAndroid),
+		),
+		Export_system_includes: bazel.MakeStringListAttribute(
+			i.SystemIncludes.SelectValue(bazel.OsConfigurationAxis, bazel.OsAndroid),
+		),
+	}
+	androidOsApiDeps := apiBazelTargets(androidOsDeps)
+	if !androidOsApiDeps.IsEmpty() {
+		androidOsAttrs.Deps = bazel.MakeLabelListAttribute(androidOsApiDeps)
+	}
+	osRet := apiIncludes{
+		name: android.ApiContributionTargetName(module.Name()) + ".androidos",
+		attrs: bazelCcApiLibraryHeadersAttributes{
+			bazelCcLibraryHeadersAttributes: androidOsAttrs,
+		},
+	}
+	return archRet, osRet
+}