Fix soong config hash missing for some modules

Bug: 279362051
Test: see outputs of C++ modules using soong config
Change-Id: I95e41350ff17a989faf7c010a4c4ed4fcd79d66b
diff --git a/android/module.go b/android/module.go
index ba32710..b554fd0 100644
--- a/android/module.go
+++ b/android/module.go
@@ -483,6 +483,7 @@
 	TargetRequiredModuleNames() []string
 
 	ModuleSubDir() string
+	SoongConfigTraceHash() string
 
 	Variable(pctx PackageContext, name, value string)
 	Rule(pctx PackageContext, name string, params blueprint.RuleParams, argNames ...string) blueprint.Rule
@@ -987,7 +988,11 @@
 	// Bazel conversion status
 	BazelConversionStatus BazelConversionStatus `blueprint:"mutated"`
 
-	// SoongConfigTrace records accesses to VendorVars (soong_config)
+	// SoongConfigTrace records accesses to VendorVars (soong_config). The trace will be hashed
+	// and used as a subdir of PathForModuleOut.  Note that we mainly focus on incremental
+	// builds among similar products (e.g. aosp_cf_x86_64_phone and aosp_cf_x86_64_foldable),
+	// and there are variables other than soong_config, which isn't captured by soong config
+	// trace, but influence modules among products.
 	SoongConfigTrace     soongConfigTrace `blueprint:"mutated"`
 	SoongConfigTraceHash string           `blueprint:"mutated"`
 }
@@ -3192,7 +3197,7 @@
 	return m.bp.ModuleSubDir()
 }
 
-func (m *moduleContext) ModuleSoongConfigHash() string {
+func (m *moduleContext) SoongConfigTraceHash() string {
 	return m.module.base().commonProperties.SoongConfigTraceHash
 }