platform_build_soong/bp2build/conversion.go
Jingwen Chen 40067de675 bp2build: support Starlark rules and load statements.
This CL adds support to bp2build for declaring the location of the
Starlark rule definition when creating BazelTargetModules. This is
needed for non-native rules that needs to be loaded from .bzl files
somewhere in the tree.

Since load statements are aggregated at the top of the BUILD file, away
from the targets that actually use them, this CL also introduces an
abstraction to group BazelTargets together and compute their load
statements and target string representations separately, allowing load
statements to be decoupled and written into a BUILD file before the
targets themselves.

Test: soong tests
Test: TH
Test: GENERATE_BAZEL_FILES=true m nothing && build/bazel/scripts/bp2build-sync.sh write && bazel cquery //bionic/...
Fixes: 178531760

Test: TH
Change-Id: Ie5f793a00006eb024eaef07ddd9fde7aaefc054e
2021-01-26 22:46:20 -05:00

127 lines
3.8 KiB
Go

package bp2build
import (
"android/soong/android"
"reflect"
"sort"
"strings"
"github.com/google/blueprint/proptools"
)
type BazelFile struct {
Dir string
Basename string
Contents string
}
func CreateBazelFiles(
ruleShims map[string]RuleShim,
buildToTargets map[string]BazelTargets,
mode CodegenMode) []BazelFile {
files := make([]BazelFile, 0, len(ruleShims)+len(buildToTargets)+numAdditionalFiles)
// Write top level files: WORKSPACE and BUILD. These files are empty.
files = append(files, newFile("", "WORKSPACE", ""))
// Used to denote that the top level directory is a package.
files = append(files, newFile("", "BUILD", ""))
files = append(files, newFile(bazelRulesSubDir, "BUILD", ""))
if mode == QueryView {
// These files are only used for queryview.
files = append(files, newFile(bazelRulesSubDir, "providers.bzl", providersBzl))
for bzlFileName, ruleShim := range ruleShims {
files = append(files, newFile(bazelRulesSubDir, bzlFileName+".bzl", ruleShim.content))
}
files = append(files, newFile(bazelRulesSubDir, "soong_module.bzl", generateSoongModuleBzl(ruleShims)))
}
files = append(files, createBuildFiles(buildToTargets, mode)...)
return files
}
func createBuildFiles(buildToTargets map[string]BazelTargets, mode CodegenMode) []BazelFile {
files := make([]BazelFile, 0, len(buildToTargets))
for _, dir := range android.SortedStringKeys(buildToTargets) {
targets := buildToTargets[dir]
sort.Slice(targets, func(i, j int) bool { return targets[i].name < targets[j].name })
content := soongModuleLoad
if mode == Bp2Build {
content = targets.LoadStatements()
}
if content != "" {
// If there are load statements, add a couple of newlines.
content += "\n\n"
}
content += targets.String()
files = append(files, newFile(dir, "BUILD.bazel", content))
}
return files
}
func newFile(dir, basename, content string) BazelFile {
return BazelFile{
Dir: dir,
Basename: basename,
Contents: content,
}
}
const (
bazelRulesSubDir = "build/bazel/queryview_rules"
// additional files:
// * workspace file
// * base BUILD file
// * rules BUILD file
// * rules providers.bzl file
// * rules soong_module.bzl file
numAdditionalFiles = 5
)
var (
// Certain module property names are blocklisted/ignored here, for the reasons commented.
ignoredPropNames = map[string]bool{
"name": true, // redundant, since this is explicitly generated for every target
"from": true, // reserved keyword
"in": true, // reserved keyword
"arch": true, // interface prop type is not supported yet.
"multilib": true, // interface prop type is not supported yet.
"target": true, // interface prop type is not supported yet.
"visibility": true, // Bazel has native visibility semantics. Handle later.
"features": true, // There is already a built-in attribute 'features' which cannot be overridden.
}
)
func shouldGenerateAttribute(prop string) bool {
return !ignoredPropNames[prop]
}
func shouldSkipStructField(field reflect.StructField) bool {
if field.PkgPath != "" {
// Skip unexported fields. Some properties are
// internal to Soong only, and these fields do not have PkgPath.
return true
}
// fields with tag `blueprint:"mutated"` are exported to enable modification in mutators, etc
// but cannot be set in a .bp file
if proptools.HasTag(field, "blueprint", "mutated") {
return true
}
return false
}
// FIXME(b/168089390): In Bazel, rules ending with "_test" needs to be marked as
// testonly = True, forcing other rules that depend on _test rules to also be
// marked as testonly = True. This semantic constraint is not present in Soong.
// To work around, rename "*_test" rules to "*_test_".
func canonicalizeModuleType(moduleName string) string {
if strings.HasSuffix(moduleName, "_test") {
return moduleName + "_"
}
return moduleName
}