R8/D8 should use sdk_version prop to determine API surface stability.

`min_sdk_version` is used to represent the api_level of the device and
its type will eventually become android.ApiLevel. OTOH,
`sdk_version` property represents the API surface a module builds against
_and_ the version of that API surface. For
R8/D8, the additional `--android-platform-build` should be determined
using the sdk_version of the soong module and not min_sdk_version, since
min_sdk_version will not contain information about the api surface used
for compilation.

The unit test for `core_platform_app` in TestR8 were passing since
min_sdk_version was not set, and therefore it implicitly defaulted to
sdk_version.

Also created a custom struct to propagate params to the helper dex
functions

Test: In build/soong, go test ./java
Test: TH
Bug: 208456999
Change-Id: I08ac6f496444d603557e498c8a1794af665abc7a

java/base.go

@@ -1488,7 +1488,14 @@ func (j *Module) compile(ctx android.ModuleContext, aaptSrcJar android.Path) {
 			}
 			// Dex compilation
 			var dexOutputFile android.OutputPath
-			dexOutputFile = j.dexer.compileDex(ctx, flags, j.MinSdkVersion(ctx), implementationAndResourcesJar, jarName)
+			params := &compileDexParams{
+				flags:         flags,
+				sdkVersion:    j.SdkVersion(ctx),
+				minSdkVersion: j.MinSdkVersion(ctx),
+				classesJar:    implementationAndResourcesJar,
+				jarName:       jarName,
+			}
+			dexOutputFile = j.dexer.compileDex(ctx, params)
 			if ctx.Failed() {
 				return
 			}

java/dex.go

@@ -180,7 +180,7 @@ var r8, r8RE = pctx.MultiCommandRemoteStaticRules("r8",
 		"r8Flags", "zipFlags", "tmpJar", "mergeZipsFlags"}, []string{"implicits"})
 
 func (d *dexer) dexCommonFlags(ctx android.ModuleContext,
-	minSdkVersion android.SdkSpec) (flags []string, deps android.Paths) {
+	dexParams *compileDexParams) (flags []string, deps android.Paths) {
 
 	flags = d.dexProperties.Dxflags
 	// Translate all the DX flags to D8 ones until all the build files have been migrated
@@ -209,11 +209,11 @@ func (d *dexer) dexCommonFlags(ctx android.ModuleContext,
 	// Note: Targets with a min SDK kind of core_platform (e.g., framework.jar) or unspecified (e.g.,
 	// services.jar), are not classified as stable, which is WAI.
 	// TODO(b/232073181): Expand to additional min SDK cases after validation.
-	if !minSdkVersion.Stable() {
+	if !dexParams.sdkVersion.Stable() {
 		flags = append(flags, "--android-platform-build")
 	}
 
-	effectiveVersion, err := minSdkVersion.EffectiveVersion(ctx)
+	effectiveVersion, err := dexParams.minSdkVersion.EffectiveVersion(ctx)
 	if err != nil {
 		ctx.PropertyErrorf("min_sdk_version", "%s", err)
 	}
@@ -317,20 +317,27 @@ func (d *dexer) r8Flags(ctx android.ModuleContext, flags javaBuilderFlags) (r8Fl
 	return r8Flags, r8Deps
 }
 
-func (d *dexer) compileDex(ctx android.ModuleContext, flags javaBuilderFlags, minSdkVersion android.SdkSpec,
-	classesJar android.Path, jarName string) android.OutputPath {
+type compileDexParams struct {
+	flags         javaBuilderFlags
+	sdkVersion    android.SdkSpec
+	minSdkVersion android.SdkSpec
+	classesJar    android.Path
+	jarName       string
+}
+
+func (d *dexer) compileDex(ctx android.ModuleContext, dexParams *compileDexParams) android.OutputPath {
 
 	// Compile classes.jar into classes.dex and then javalib.jar
-	javalibJar := android.PathForModuleOut(ctx, "dex", jarName).OutputPath
+	javalibJar := android.PathForModuleOut(ctx, "dex", dexParams.jarName).OutputPath
 	outDir := android.PathForModuleOut(ctx, "dex")
-	tmpJar := android.PathForModuleOut(ctx, "withres-withoutdex", jarName)
+	tmpJar := android.PathForModuleOut(ctx, "withres-withoutdex", dexParams.jarName)
 
 	zipFlags := "--ignore_missing_files"
 	if proptools.Bool(d.dexProperties.Uncompress_dex) {
 		zipFlags += " -L 0"
 	}
 
-	commonFlags, commonDeps := d.dexCommonFlags(ctx, minSdkVersion)
+	commonFlags, commonDeps := d.dexCommonFlags(ctx, dexParams)
 
 	// Exclude kotlinc generated files when "exclude_kotlinc_generated_files" is set to true.
 	mergeZipsFlags := ""
@@ -347,7 +354,7 @@ func (d *dexer) compileDex(ctx android.ModuleContext, flags javaBuilderFlags, mi
 			android.ModuleNameWithPossibleOverride(ctx), "unused.txt")
 		proguardUsageZip := android.PathForModuleOut(ctx, "proguard_usage.zip")
 		d.proguardUsageZip = android.OptionalPathForPath(proguardUsageZip)
-		r8Flags, r8Deps := d.r8Flags(ctx, flags)
+		r8Flags, r8Deps := d.r8Flags(ctx, dexParams.flags)
 		r8Deps = append(r8Deps, commonDeps...)
 		rule := r8
 		args := map[string]string{
@@ -370,12 +377,12 @@ func (d *dexer) compileDex(ctx android.ModuleContext, flags javaBuilderFlags, mi
 			Description:     "r8",
 			Output:          javalibJar,
 			ImplicitOutputs: android.WritablePaths{proguardDictionary, proguardUsageZip},
-			Input:           classesJar,
+			Input:           dexParams.classesJar,
 			Implicits:       r8Deps,
 			Args:            args,
 		})
 	} else {
-		d8Flags, d8Deps := d8Flags(flags)
+		d8Flags, d8Deps := d8Flags(dexParams.flags)
 		d8Deps = append(d8Deps, commonDeps...)
 		rule := d8
 		if ctx.Config().UseRBE() && ctx.Config().IsEnvTrue("RBE_D8") {
@@ -385,7 +392,7 @@ func (d *dexer) compileDex(ctx android.ModuleContext, flags javaBuilderFlags, mi
 			Rule:        rule,
 			Description: "d8",
 			Output:      javalibJar,
-			Input:       classesJar,
+			Input:       dexParams.classesJar,
 			Implicits:   d8Deps,
 			Args: map[string]string{
 				"d8Flags":        strings.Join(append(commonFlags, d8Flags...), " "),
@@ -397,7 +404,7 @@ func (d *dexer) compileDex(ctx android.ModuleContext, flags javaBuilderFlags, mi
 		})
 	}
 	if proptools.Bool(d.dexProperties.Uncompress_dex) {
-		alignedJavalibJar := android.PathForModuleOut(ctx, "aligned", jarName).OutputPath
+		alignedJavalibJar := android.PathForModuleOut(ctx, "aligned", dexParams.jarName).OutputPath
 		TransformZipAlign(ctx, alignedJavalibJar, javalibJar)
 		javalibJar = alignedJavalibJar
 	}

java/dex_test.go

@@ -41,6 +41,7 @@ func TestR8(t *testing.T) {
 			name: "core_platform_app",
 			srcs: ["foo.java"],
 			sdk_version: "core_platform",
+			min_sdk_version: "31",
 		}
 
 		java_library {

java/java.go

@@ -1981,7 +1981,15 @@ func (j *Import) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 			j.dexpreopter.uncompressedDex = *j.dexProperties.Uncompress_dex
 
 			var dexOutputFile android.OutputPath
-			dexOutputFile = j.dexer.compileDex(ctx, flags, j.MinSdkVersion(ctx), outputFile, jarName)
+			dexParams := &compileDexParams{
+				flags:         flags,
+				sdkVersion:    j.SdkVersion(ctx),
+				minSdkVersion: j.MinSdkVersion(ctx),
+				classesJar:    outputFile,
+				jarName:       jarName,
+			}
+
+			dexOutputFile = j.dexer.compileDex(ctx, dexParams)
 			if ctx.Failed() {
 				return
 			}