bp2build: build static version of libstdc++.

This CL adds the ability to filter cc_library modules to only generate
their static variant of their shared variant isn't ready.

For example, the libstdc++ library is buildable as a static library,
which libc depends on. However, the shared variant of libstdc++ depends
on libc, which has to come later.

This CL introduces that abstraction to break up bp2build conversion into
more atomic steps to help with conversion.

Test: TH (bazel build //bionic/... incl. libstdc++'s static variant)
Bug: 186489250
Bug: 186822597

Change-Id: I3e2fe748e4e3d3b656760da4807f342d67c8f45f

android/bazel.go

@@ -210,7 +210,6 @@ var (
 		"libc_tzcode",           // http://b/186822591, cc_library_static, localtime.c:84:46: error: expected expression
 		"libc_bionic_ndk",       // http://b/186822256, cc_library_static, signal.cpp:186:52: error: ISO C++ requires field designators to be specified in declaration order
 		"libc_malloc_hooks",     // http://b/187016307, cc_library, ld.lld: error: undefined symbol: __malloc_hook
-		"libstdc++",             // http://b/186822597, cc_library, ld.lld: error: undefined symbol: __errno
 		"libm",                  // http://b/183064661, cc_library, math.h:25:16: error: unexpected token in argument list
 
 		// http://b/186823769: Needs C++ STL support, includes from unconverted standard libraries in //external/libcxx
@@ -237,6 +236,12 @@ var (
 		"libjemalloc5_unittest",
 	}
 
+	// Per-module denylist of cc_library modules to only generate the static
+	// variant if their shared variant isn't ready or buildable by Bazel.
+	bp2buildCcLibraryStaticOnlyList = []string{
+		"libstdc++", // http://b/186822597, cc_library, ld.lld: error: undefined symbol: __errno
+	}
+
 	// Per-module denylist to opt modules out of mixed builds. Such modules will
 	// still be generated via bp2build.
 	mixedBuildsDisabledList = []string{
@@ -250,6 +255,7 @@ var (
 	// Used for quicker lookups
 	bp2buildDoNotWriteBuildFile = map[string]bool{}
 	bp2buildModuleDoNotConvert  = map[string]bool{}
+	bp2buildCcLibraryStaticOnly = map[string]bool{}
 	mixedBuildsDisabled         = map[string]bool{}
 )
 
@@ -262,11 +268,19 @@ func init() {
 		bp2buildModuleDoNotConvert[moduleName] = true
 	}
 
+	for _, moduleName := range bp2buildCcLibraryStaticOnlyList {
+		bp2buildCcLibraryStaticOnly[moduleName] = true
+	}
+
 	for _, moduleName := range mixedBuildsDisabledList {
 		mixedBuildsDisabled[moduleName] = true
 	}
 }
 
+func GenerateCcLibraryStaticOnly(ctx BazelConversionPathContext) bool {
+	return bp2buildCcLibraryStaticOnly[ctx.Module().Name()]
+}
+
 func ShouldWriteBuildFileForDir(dir string) bool {
 	if _, ok := bp2buildDoNotWriteBuildFile[dir]; ok {
 		return false
@@ -284,6 +298,12 @@ func (b *BazelModuleBase) MixedBuildsEnabled(ctx BazelConversionPathContext) boo
 	if len(b.GetBazelLabel(ctx, ctx.Module())) == 0 {
 		return false
 	}
+	if GenerateCcLibraryStaticOnly(ctx) {
+		// Don't use partially-converted cc_library targets in mixed builds,
+		// since mixed builds would generally rely on both static and shared
+		// variants of a cc_library.
+		return false
+	}
 	return !mixedBuildsDisabled[ctx.Module().Name()]
 }
 

cc/library.go

@@ -259,6 +259,14 @@ func CcLibraryBp2Build(ctx android.TopDownMutatorContext) {
 		return
 	}
 
+	// For some cc_library modules, their static variants are ready to be
+	// converted, but not their shared variants. For these modules, delegate to
+	// the cc_library_static bp2build converter temporarily instead.
+	if android.GenerateCcLibraryStaticOnly(ctx) {
+		ccLibraryStaticBp2BuildInternal(ctx, m)
+		return
+	}
+
 	sharedAttrs := bp2BuildParseSharedProps(ctx, m)
 	staticAttrs := bp2BuildParseStaticProps(ctx, m)
 	compilerAttrs := bp2BuildParseCompilerProps(ctx, m)
@@ -2205,6 +2213,28 @@ func BazelCcLibraryStaticFactory() android.Module {
 	return module
 }
 
+func ccLibraryStaticBp2BuildInternal(ctx android.TopDownMutatorContext, module *Module) {
+	compilerAttrs := bp2BuildParseCompilerProps(ctx, module)
+	linkerAttrs := bp2BuildParseLinkerProps(ctx, module)
+	exportedIncludes := bp2BuildParseExportedIncludes(ctx, module)
+
+	attrs := &bazelCcLibraryStaticAttributes{
+		Copts:      compilerAttrs.copts,
+		Srcs:       compilerAttrs.srcs,
+		Deps:       linkerAttrs.deps,
+		Linkopts:   linkerAttrs.linkopts,
+		Linkstatic: true,
+		Includes:   exportedIncludes,
+	}
+
+	props := bazel.BazelTargetModuleProperties{
+		Rule_class:        "cc_library_static",
+		Bzl_load_location: "//build/bazel/rules:cc_library_static.bzl",
+	}
+
+	ctx.CreateBazelTargetModule(BazelCcLibraryStaticFactory, module.Name(), props, attrs)
+}
+
 func CcLibraryStaticBp2Build(ctx android.TopDownMutatorContext) {
 	module, ok := ctx.Module().(*Module)
 	if !ok {
@@ -2218,24 +2248,7 @@ func CcLibraryStaticBp2Build(ctx android.TopDownMutatorContext) {
 		return
 	}
 
-	compilerAttrs := bp2BuildParseCompilerProps(ctx, module)
-	linkerAttrs := bp2BuildParseLinkerProps(ctx, module)
-	exportedIncludes := bp2BuildParseExportedIncludes(ctx, module)
-
-	attrs := &bazelCcLibraryStaticAttributes{
-		Copts:      compilerAttrs.copts,
-		Srcs:       compilerAttrs.srcs,
-		Deps:       linkerAttrs.deps,
-		Linkstatic: true,
-		Includes:   exportedIncludes,
-	}
-
-	props := bazel.BazelTargetModuleProperties{
-		Rule_class:        "cc_library_static",
-		Bzl_load_location: "//build/bazel/rules:cc_library_static.bzl",
-	}
-
-	ctx.CreateBazelTargetModule(BazelCcLibraryStaticFactory, module.Name(), props, attrs)
+	ccLibraryStaticBp2BuildInternal(ctx, module)
 }
 
 func (m *bazelCcLibraryStatic) Name() string {