bp2build: automatically convert all genrules.

Results of `cquery //bionic/...`: https://paste.googleplex.com/5608885982330880?raw

Note that this CL does not contain the global module name mapping to
fully qualified label lookup mechanism, so while the BUILD targets are
queryable, they are not buildable (yet).

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

Change-Id: I6f2316222723d8b612d9b041ca82a188cd05bac9

bp2build/Android.bp

@@ -11,6 +11,7 @@ bootstrap_go_package {
     deps: [
         "soong-android",
         "soong-bazel",
+        "soong-genrule",
     ],
     testSrcs: [
         "build_conversion_test.go",

bp2build/build_conversion_test.go

@@ -16,6 +16,7 @@ package bp2build
 
 import (
 	"android/soong/android"
+	"android/soong/genrule"
 	"testing"
 )
 
@@ -300,6 +301,54 @@ func TestModuleTypeBp2Build(t *testing.T) {
         "a",
         "b",
     ],
+)`,
+		},
+		{
+			moduleTypeUnderTest:        "genrule",
+			moduleTypeUnderTestFactory: genrule.GenRuleFactory,
+			bp: `genrule {
+    name: "foo",
+    out: ["foo.out"],
+    srcs: ["foo.in"],
+    tool_files: [":foo.tool"],
+    cmd: "$(location :foo.tool) arg $(in) $(out)",
+}`,
+			expectedBazelTarget: `genrule(
+    name = "foo",
+    cmd = "$(location :foo.tool) arg $(SRCS) $(OUTS)",
+    outs = [
+        "foo.out",
+    ],
+    srcs = [
+        "foo.in",
+    ],
+    tools = [
+        ":foo.tool",
+    ],
+)`,
+		},
+		{
+			moduleTypeUnderTest:        "genrule",
+			moduleTypeUnderTestFactory: genrule.GenRuleFactory,
+			bp: `genrule {
+    name: "foo",
+    out: ["foo.out"],
+    srcs: ["foo.in"],
+    tools: [":foo.tool"],
+    cmd: "$(location :foo.tool) --out-dir=$(genDir) $(in)",
+}`,
+			expectedBazelTarget: `genrule(
+    name = "foo",
+    cmd = "$(location :foo.tool) --out-dir=$(GENDIR) $(SRCS)",
+    outs = [
+        "foo.out",
+    ],
+    srcs = [
+        "foo.in",
+    ],
+    tools = [
+        ":foo.tool",
+    ],
 )`,
 		},
 	}

genrule/genrule.go

@@ -46,6 +46,8 @@ func RegisterGenruleBuildComponents(ctx android.RegistrationContext) {
 	ctx.FinalDepsMutators(func(ctx android.RegisterMutatorsContext) {
 		ctx.BottomUp("genrule_tool_deps", toolDepsMutator).Parallel()
 	})
+
+	android.RegisterBp2BuildMutator("genrule", bp2buildMutator)
 }
 
 var (
@@ -772,6 +774,70 @@ type genRuleProperties struct {
 	Out []string `android:"arch_variant"`
 }
 
+type bazelGenruleAttributes struct {
+	Name  *string
+	Srcs  []string
+	Outs  []string
+	Tools []string
+	Cmd   string
+}
+
+type bazelGenrule struct {
+	android.BazelTargetModuleBase
+	bazelGenruleAttributes
+}
+
+func BazelGenruleFactory() android.Module {
+	module := &bazelGenrule{}
+	module.AddProperties(&module.bazelGenruleAttributes)
+	android.InitBazelTargetModule(module)
+	return module
+}
+
+func bp2buildMutator(ctx android.TopDownMutatorContext) {
+	if m, ok := ctx.Module().(*Module); ok {
+		name := "__bp2build__" + m.Name()
+		// Replace in and out variables with $< and $@
+		var cmd string
+		if m.properties.Cmd != nil {
+			cmd = strings.Replace(*m.properties.Cmd, "$(in)", "$(SRCS)", -1)
+			cmd = strings.Replace(cmd, "$(out)", "$(OUTS)", -1)
+			cmd = strings.Replace(cmd, "$(genDir)", "$(GENDIR)", -1)
+		}
+
+		// 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 m.GetProperties() {
+			if props, ok := propIntf.(*genRuleProperties); ok {
+				outs = props.Out
+				break
+			}
+		}
+
+		// Bazel only has the "tools" attribute.
+		tools := append(m.properties.Tools, m.properties.Tool_files...)
+
+		// Create the BazelTargetModule.
+		ctx.CreateModule(BazelGenruleFactory, &bazelGenruleAttributes{
+			Name:  proptools.StringPtr(name),
+			Srcs:  m.properties.Srcs,
+			Outs:  outs,
+			Cmd:   cmd,
+			Tools: tools,
+		}, &bazel.BazelTargetModuleProperties{
+			Rule_class: "genrule",
+		})
+	}
+}
+
+func (m *bazelGenrule) Name() string {
+	return m.BaseModuleName()
+}
+
+func (m *bazelGenrule) GenerateAndroidBuildActions(ctx android.ModuleContext) {}
+
 var Bool = proptools.Bool
 var String = proptools.String