Enable -funique-internal-linkage-names when afdo=true
We used to enable unique names only when a profile is available.
But A profile generated for a binary without unique names doesn't
work well when building a binary with unique names. To avoid a
chicken-and-egg problem, this CL enables the flag when afdo=true,
whether a profile exists or not.
Bug: 241523910
Test: build
Change-Id: I74d834510d81d2db76e34d0488c74a60e1fcecd5
diff --git a/cc/afdo.go b/cc/afdo.go
index be4f50a..49f6987 100644
--- a/cc/afdo.go
+++ b/cc/afdo.go
@@ -34,7 +34,7 @@
var afdoProfileProjectsConfigKey = android.NewOnceKey("AfdoProfileProjects")
-const afdoCFlagsFormat = "-funique-internal-linkage-names -fprofile-sample-accurate -fprofile-sample-use=%s"
+const afdoCFlagsFormat = "-fprofile-sample-accurate -fprofile-sample-use=%s"
func recordMissingAfdoProfileFile(ctx android.BaseModuleContext, missing string) {
getNamedMapForConfig(ctx.Config(), modulesMissingProfileFileKey).Store(missing, true)
@@ -66,10 +66,24 @@
// afdoEnabled returns true for binaries and shared libraries
// that set afdo prop to True and there is a profile available
func (afdo *afdo) afdoEnabled() bool {
- return afdo != nil && afdo.Properties.Afdo && afdo.Properties.FdoProfilePath != nil
+ return afdo != nil && afdo.Properties.Afdo
}
func (afdo *afdo) flags(ctx ModuleContext, flags Flags) Flags {
+ if afdo.Properties.Afdo {
+ // We use `-funique-internal-linkage-names` to associate profiles to the right internal
+ // functions. This option should be used before generating a profile. Because a profile
+ // generated for a binary without unique names doesn't work well building a binary with
+ // unique names (they have different internal function names).
+ // To avoid a chicken-and-egg problem, we enable `-funique-internal-linkage-names` when
+ // `afdo=true`, whether a profile exists or not.
+ // The profile can take effect in three steps:
+ // 1. Add `afdo: true` in Android.bp, and build the binary.
+ // 2. Collect an AutoFDO profile for the binary.
+ // 3. Make the profile searchable by the build system. So it's used the next time the binary
+ // is built.
+ flags.Local.CFlags = append([]string{"-funique-internal-linkage-names"}, flags.Local.CFlags...)
+ }
if path := afdo.Properties.FdoProfilePath; path != nil {
// The flags are prepended to allow overriding.
profileUseFlag := fmt.Sprintf(afdoCFlagsFormat, *path)
@@ -129,42 +143,41 @@
// Propagate afdo requirements down from binaries and shared libraries
func afdoDepsMutator(mctx android.TopDownMutatorContext) {
if m, ok := mctx.Module().(*Module); ok && m.afdo.afdoEnabled() {
- if path := m.afdo.Properties.FdoProfilePath; path != nil {
- mctx.WalkDeps(func(dep android.Module, parent android.Module) bool {
- tag := mctx.OtherModuleDependencyTag(dep)
- libTag, isLibTag := tag.(libraryDependencyTag)
+ path := m.afdo.Properties.FdoProfilePath
+ mctx.WalkDeps(func(dep android.Module, parent android.Module) bool {
+ tag := mctx.OtherModuleDependencyTag(dep)
+ libTag, isLibTag := tag.(libraryDependencyTag)
- // Do not recurse down non-static dependencies
- if isLibTag {
- if !libTag.static() {
- return false
- }
- } else {
- if tag != objDepTag && tag != reuseObjTag {
- return false
- }
+ // Do not recurse down non-static dependencies
+ if isLibTag {
+ if !libTag.static() {
+ return false
}
-
- if dep, ok := dep.(*Module); ok {
- dep.afdo.Properties.AfdoRDeps = append(
- dep.afdo.Properties.AfdoRDeps,
- afdoRdep{
- VariationName: proptools.StringPtr(encodeTarget(m.Name())),
- ProfilePath: path,
- },
- )
+ } else {
+ if tag != objDepTag && tag != reuseObjTag {
+ return false
}
+ }
- return true
- })
- }
+ if dep, ok := dep.(*Module); ok {
+ dep.afdo.Properties.AfdoRDeps = append(
+ dep.afdo.Properties.AfdoRDeps,
+ afdoRdep{
+ VariationName: proptools.StringPtr(encodeTarget(m.Name())),
+ ProfilePath: path,
+ },
+ )
+ }
+
+ return true
+ })
}
}
// Create afdo variants for modules that need them
func afdoMutator(mctx android.BottomUpMutatorContext) {
if m, ok := mctx.Module().(*Module); ok && m.afdo != nil {
- if !m.static() && m.afdo.Properties.Afdo && m.afdo.Properties.FdoProfilePath != nil {
+ if !m.static() && m.afdo.Properties.Afdo {
mctx.SetDependencyVariation(encodeTarget(m.Name()))
return
}
@@ -182,7 +195,7 @@
// \ ^
// ----------------------|
// We only need to create one variant per unique rdep
- if variantNameToProfilePath[variantName] == nil {
+ if _, exists := variantNameToProfilePath[variantName]; !exists {
variationNames = append(variationNames, variantName)
variantNameToProfilePath[variantName] = afdoRDep.ProfilePath
}
@@ -197,6 +210,7 @@
variation := modules[i].(*Module)
variation.Properties.PreventInstall = true
variation.Properties.HideFromMake = true
+ variation.afdo.Properties.Afdo = true
variation.afdo.Properties.FdoProfilePath = variantNameToProfilePath[name]
}
}