cc Bp2build support for genrules that generate .proto file

If `srcs` contains a gensrcs/genrule module, the current bp2build module
will put it in the catch-all `srcs` attribute. This is reserved for .cpp
sources, so if the genrule produces a .proto/.aidl/... file, this will
fail.

This handles genrules that produce .proto files. To implement this, this
creates an additional partition that detects if the other module is a
genrule/gensrc that produces .proto files. If true, it will append it to
the proto partition.

This CL does not handle
- genrule that produce .c/.aidl/.yacc/.... files. They will continue to
  be partitioned into the catch-all partition
- java modules

Test: unit tests
Test: TH
Bug: 293205700
Change-Id: Ib720fdf3a053ff5dd256e6faa632e3fa7776966d

bp2build/cc_library_static_conversion_test.go

@@ -2247,3 +2247,38 @@ cc_library_static{
     ]`,
 			})}})
 }
+
+func TestCcLibraryWithProtoInGeneratedSrcs(t *testing.T) {
+	runCcLibraryStaticTestCase(t, Bp2buildTestCase{
+		Description:                "cc_library with a .proto file generated from a genrule",
+		ModuleTypeUnderTest:        "cc_library_static",
+		ModuleTypeUnderTestFactory: cc.LibraryStaticFactory,
+		Blueprint: soongCcLibraryPreamble + `
+cc_library_static {
+	name: "mylib",
+	generated_sources: ["myprotogen"],
+}
+genrule {
+	name: "myprotogen",
+	out: ["myproto.proto"],
+}
+` + simpleModuleDoNotConvertBp2build("cc_library", "libprotobuf-cpp-lite"),
+		ExpectedBazelTargets: []string{
+			MakeBazelTarget("cc_library_static", "mylib", AttrNameToString{
+				"local_includes":                    `["."]`,
+				"deps":                              `[":libprotobuf-cpp-lite"]`,
+				"implementation_whole_archive_deps": `[":mylib_cc_proto_lite"]`,
+			}),
+			MakeBazelTarget("cc_lite_proto_library", "mylib_cc_proto_lite", AttrNameToString{
+				"deps": `[":mylib_proto"]`,
+			}),
+			MakeBazelTarget("proto_library", "mylib_proto", AttrNameToString{
+				"srcs": `[":myprotogen"]`,
+			}),
+			MakeBazelTargetNoRestrictions("genrule", "myprotogen", AttrNameToString{
+				"cmd":  `""`,
+				"outs": `["myproto.proto"]`,
+			}),
+		},
+	})
+}

cc/bp2build.go

@@ -48,6 +48,8 @@ const (
 
 	genrulePartition = "genrule"
 
+	protoFromGenPartition = "proto_gen"
+
 	hdrPartition = "hdr"
 
 	stubsSuffix = "_stub_libs_current"
@@ -126,6 +128,41 @@ func (m *Module) convertTidyAttributes(ctx android.BaseMutatorContext, moduleAtt
 	}
 }
 
+// Returns an unchanged label and a bool indicating whether the dep is a genrule that produces .proto files
+func protoFromGenPartitionMapper(pathCtx android.BazelConversionContext) bazel.LabelMapper {
+	return func(ctx bazel.OtherModuleContext, label bazel.Label) (string, bool) {
+		mod, exists := ctx.ModuleFromName(label.OriginalModuleName)
+		if !exists {
+			return label.Label, false
+		}
+		gen, isGen := mod.(*genrule.Module)
+		if !isGen {
+			return label.Label, false
+		}
+		if containsProto(ctx, gen.RawOutputFiles(pathCtx)) {
+			// Return unmodified label + true
+			// True will ensure that this module gets dropped from `srcs` of the generated cc_* target. `srcs` is reserved for .cpp files
+			return label.Label, true
+		}
+		return label.Label, false
+	}
+}
+
+// Returns true if srcs contains only .proto files
+// Raises an exception if there is a combination of .proto and non .proto srcs
+func containsProto(ctx bazel.OtherModuleContext, srcs []string) bool {
+	onlyProtos := false
+	for _, src := range srcs {
+		if strings.HasSuffix(src, ".proto") {
+			onlyProtos = true
+		} else if onlyProtos {
+			// This is not a proto file, and we have encountered a .proto file previously
+			ctx.ModuleErrorf("TOOD: Add bp2build support combination of .proto and non .proto files in outs of genrule")
+		}
+	}
+	return onlyProtos
+}
+
 // groupSrcsByExtension partitions `srcs` into groups based on file extension.
 func groupSrcsByExtension(ctx android.BazelConversionPathContext, srcs bazel.LabelListAttribute) bazel.PartitionToLabelListAttribute {
 	// Convert filegroup dependencies into extension-specific filegroups filtered in the filegroup.bzl
@@ -159,10 +196,11 @@ func groupSrcsByExtension(ctx android.BazelConversionPathContext, srcs bazel.Lab
 		// 		contains .l or .ll files we will need to find a way to add a
 		// 		LabelMapper for these that identifies these filegroups and
 		//		converts them appropriately
-		lSrcPartition:       bazel.LabelPartition{Extensions: []string{".l"}},
+		lSrcPartition:         bazel.LabelPartition{Extensions: []string{".l"}},
-		llSrcPartition:      bazel.LabelPartition{Extensions: []string{".ll"}},
+		llSrcPartition:        bazel.LabelPartition{Extensions: []string{".ll"}},
-		rScriptSrcPartition: bazel.LabelPartition{Extensions: []string{".fs", ".rscript"}},
+		rScriptSrcPartition:   bazel.LabelPartition{Extensions: []string{".fs", ".rscript"}},
-		xsdSrcPartition:     bazel.LabelPartition{LabelMapper: android.XsdLabelMapper(xsdConfigCppTarget)},
+		xsdSrcPartition:       bazel.LabelPartition{LabelMapper: android.XsdLabelMapper(xsdConfigCppTarget)},
+		protoFromGenPartition: bazel.LabelPartition{LabelMapper: protoFromGenPartitionMapper(ctx)},
 		// C++ is the "catch-all" group, and comprises generated sources because we don't
 		// know the language of these sources until the genrule is executed.
 		cppSrcPartition:     bazel.LabelPartition{Extensions: []string{".cpp", ".cc", ".cxx", ".mm"}, LabelMapper: addSuffixForFilegroup("_cpp_srcs"), Keep_remainder: true},
@@ -594,6 +632,7 @@ func (ca *compilerAttributes) finalize(ctx android.BazelConversionPathContext, i
 	partitionedHdrs := partitionHeaders(ctx, exportHdrs)
 
 	ca.protoSrcs = partitionedSrcs[protoSrcPartition]
+	ca.protoSrcs.Append(partitionedSrcs[protoFromGenPartition])
 	ca.aidlSrcs = partitionedSrcs[aidlSrcPartition]
 
 	for p, lla := range partitionedSrcs {

genrule/genrule.go

@@ -1012,16 +1012,7 @@ func (m *Module) ConvertWithBp2build(ctx android.TopDownMutatorContext) {
 			Tags: tags,
 		}, attrs)
 	} else {
-		// The Out prop is not in an immediately accessible field
+		outs := m.RawOutputFiles(ctx)
-		// in the Module struct, so use GetProperties and cast it
-		// to the known struct prop.
-		var outs []string
-		for _, propIntf := range m.GetProperties() {
-			if props, ok := propIntf.(*genRuleProperties); ok {
-				outs = props.Out
-				break
-			}
-		}
 		for _, out := range outs {
 			if out == bazelName {
 				// This is a workaround to circumvent a Bazel warning where a genrule's
@@ -1096,6 +1087,25 @@ type ccHeaderLibraryAttrs struct {
 	Export_includes []string
 }
 
+// RawOutputFfiles returns the raw outputs specified in Android.bp
+// This does not contain the fully resolved path relative to the top of the tree
+func (g *Module) RawOutputFiles(ctx android.BazelConversionContext) []string {
+	if ctx.Config().BuildMode != android.Bp2build {
+		ctx.ModuleErrorf("RawOutputFiles is only supported in bp2build mode")
+	}
+	// The Out prop is not in an immediately accessible field
+	// in the Module struct, so use GetProperties and cast it
+	// to the known struct prop.
+	var outs []string
+	for _, propIntf := range g.GetProperties() {
+		if props, ok := propIntf.(*genRuleProperties); ok {
+			outs = props.Out
+			break
+		}
+	}
+	return outs
+}
+
 var Bool = proptools.Bool
 var String = proptools.String