Add environment variables to cc_genrule commands

Pass the architecture, mulitlib type and native bridge state to
each variant of a cc_genrule rule as environment variables.

Bug: 200872604
Test: TestCmdPrefix
Change-Id: I39c4c2d5bbd4f4cc72a4777715db1df049345b37

cc/genrule.go

@@ -15,6 +15,8 @@
 package cc
 
 import (
+	"fmt"
+
 	"android/soong/android"
 	"android/soong/genrule"
 	"android/soong/snapshot"
@@ -36,13 +38,23 @@ type GenruleExtraProperties struct {
 
 // cc_genrule is a genrule that can depend on other cc_* objects.
 // The cmd may be run multiple times, once for each of the different arch/etc
-// variations.
+// variations.  The following environment variables will be set when the command
+// execute:
+//
+//   CC_ARCH           the name of the architecture the command is being executed for
+//
+//   CC_MULTILIB       "lib32" if the architecture the command is being executed for is 32-bit,
+//                     "lib64" if it is 64-bit.
+//
+//   CC_NATIVE_BRIDGE  the name of the subdirectory that native bridge libraries are stored in if
+//                     the architecture has native bridge enabled, empty if it is disabled.
 func GenRuleFactory() android.Module {
 	module := genrule.NewGenRule()
 
 	extra := &GenruleExtraProperties{}
 	module.Extra = extra
 	module.ImageInterface = extra
+	module.CmdModifier = genruleCmdModifier
 	module.AddProperties(module.Extra)
 
 	android.InitAndroidArchModule(module, android.HostAndDeviceSupported, android.MultilibBoth)
@@ -53,6 +65,13 @@ func GenRuleFactory() android.Module {
 	return module
 }
 
+func genruleCmdModifier(ctx android.ModuleContext, cmd string) string {
+	target := ctx.Target()
+	arch := target.Arch.ArchType
+	return fmt.Sprintf("CC_ARCH=%s CC_NATIVE_BRIDGE=%s CC_MULTILIB=%s && %s",
+		arch.Name, target.NativeBridgeRelativePath, arch.Multilib, cmd)
+}
+
 var _ android.ImageInterface = (*GenruleExtraProperties)(nil)
 
 func (g *GenruleExtraProperties) ImageMutatorBegin(ctx android.BaseModuleContext) {}

cc/genrule_test.go

@@ -115,3 +115,75 @@ func TestLibraryGenruleCmd(t *testing.T) {
 		t.Errorf(`want inputs %v, got %v`, expected, got)
 	}
 }
+
+func TestCmdPrefix(t *testing.T) {
+	bp := `
+		cc_genrule {
+			name: "gen",
+			cmd: "echo foo",
+			out: ["out"],
+			native_bridge_supported: true,
+		}
+		`
+
+	testCases := []struct {
+		name     string
+		variant  string
+		preparer android.FixturePreparer
+
+		arch         string
+		nativeBridge string
+		multilib     string
+	}{
+		{
+			name:     "arm",
+			variant:  "android_arm_armv7-a-neon",
+			arch:     "arm",
+			multilib: "lib32",
+		},
+		{
+			name:     "arm64",
+			variant:  "android_arm64_armv8-a",
+			arch:     "arm64",
+			multilib: "lib64",
+		},
+		{
+			name:    "nativebridge",
+			variant: "android_native_bridge_arm_armv7-a-neon",
+			preparer: android.FixtureModifyConfig(func(config android.Config) {
+				config.Targets[android.Android] = []android.Target{
+					{
+						Os:           android.Android,
+						Arch:         android.Arch{ArchType: android.X86, ArchVariant: "silvermont", Abi: []string{"armeabi-v7a"}},
+						NativeBridge: android.NativeBridgeDisabled,
+					},
+					{
+						Os:                       android.Android,
+						Arch:                     android.Arch{ArchType: android.Arm, ArchVariant: "armv7-a-neon", Abi: []string{"armeabi-v7a"}},
+						NativeBridge:             android.NativeBridgeEnabled,
+						NativeBridgeHostArchName: "x86",
+						NativeBridgeRelativePath: "arm",
+					},
+				}
+			}),
+			arch:         "arm",
+			multilib:     "lib32",
+			nativeBridge: "arm",
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.name, func(t *testing.T) {
+			result := android.GroupFixturePreparers(
+				PrepareForIntegrationTestWithCc,
+				android.OptionalFixturePreparer(tt.preparer),
+			).RunTestWithBp(t, bp)
+			gen := result.ModuleForTests("gen", tt.variant)
+			sboxProto := android.RuleBuilderSboxProtoForTests(t, gen.Output("genrule.sbox.textproto"))
+			cmd := *sboxProto.Commands[0].Command
+			android.AssertStringDoesContain(t, "incorrect CC_ARCH", cmd, "CC_ARCH="+tt.arch+" ")
+			android.AssertStringDoesContain(t, "incorrect CC_NATIVE_BRIDGE", cmd, "CC_NATIVE_BRIDGE="+tt.nativeBridge+" ")
+			android.AssertStringDoesContain(t, "incorrect CC_MULTILIB", cmd, "CC_MULTILIB="+tt.multilib+" ")
+		})
+	}
+}

genrule/genrule.go

@@ -156,6 +156,11 @@ type Module struct {
 	// For other packages to make their own genrules with extra
 	// properties
 	Extra interface{}
+
+	// CmdModifier can be set by wrappers around genrule to modify the command, for example to
+	// prefix environment variables to it.
+	CmdModifier func(ctx android.ModuleContext, cmd string) string
+
 	android.ImageInterface
 
 	properties generatorProperties
@@ -398,8 +403,13 @@ func (g *Module) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	var outputFiles android.WritablePaths
 	var zipArgs strings.Builder
 
+	cmd := String(g.properties.Cmd)
+	if g.CmdModifier != nil {
+		cmd = g.CmdModifier(ctx, cmd)
+	}
+
 	// Generate tasks, either from genrule or gensrcs.
-	for _, task := range g.taskGenerator(ctx, String(g.properties.Cmd), srcFiles) {
+	for _, task := range g.taskGenerator(ctx, cmd, srcFiles) {
 		if len(task.out) == 0 {
 			ctx.ModuleErrorf("must have at least one output file")
 			return