From 15fa8145609d358e27f4bcfefffb64eb33c06f00 Mon Sep 17 00:00:00 2001
From: Colin Cross <ccross@android.com>
Date: Wed, 7 Feb 2024 15:09:08 -0800
Subject: [PATCH] Disable more of AFDO for host modules

afdo.addDep would never add a depencency on a profile for a host
module, but afdoDepsMutator would still propagate AfdoRDeps to
dependencies, afdoMutator would still create afdo variants, and
afdo.flags would still add the -funique-internal-linkage-names
flag.  Exit early from all of these functions, since the afdo
variations will never be useful.

Test: afdo_test.go
Change-Id: I255fcbb86c99871916e571fbc74075d918b24745
---
 cc/afdo.go      | 12 ++++++++++++
 cc/afdo_test.go | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/cc/afdo.go b/cc/afdo.go
index 79fbae157..6cc17467d 100644
--- a/cc/afdo.go
+++ b/cc/afdo.go
@@ -68,6 +68,10 @@ func (afdo *afdo) afdoEnabled() bool {
 }
 
 func (afdo *afdo) flags(ctx ModuleContext, flags Flags) Flags {
+	if ctx.Host() {
+		return 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
@@ -147,6 +151,10 @@ var _ FdoProfileMutatorInterface = (*Module)(nil)
 
 // Propagate afdo requirements down from binaries and shared libraries
 func afdoDepsMutator(mctx android.TopDownMutatorContext) {
+	if mctx.Host() {
+		return
+	}
+
 	if m, ok := mctx.Module().(*Module); ok && m.afdo.afdoEnabled() {
 		path := m.afdo.Properties.FdoProfilePath
 		mctx.WalkDeps(func(dep android.Module, parent android.Module) bool {
@@ -181,6 +189,10 @@ func afdoDepsMutator(mctx android.TopDownMutatorContext) {
 
 // Create afdo variants for modules that need them
 func afdoMutator(mctx android.BottomUpMutatorContext) {
+	if mctx.Host() {
+		return
+	}
+
 	if m, ok := mctx.Module().(*Module); ok && m.afdo != nil {
 		if !m.static() && m.afdo.Properties.Afdo {
 			mctx.SetDependencyVariation(encodeTarget(m.Name()))
diff --git a/cc/afdo_test.go b/cc/afdo_test.go
index 65dc032d4..3eab03921 100644
--- a/cc/afdo_test.go
+++ b/cc/afdo_test.go
@@ -42,6 +42,7 @@ func TestAfdoDeps(t *testing.T) {
 	bp := `
 	cc_library_shared {
 		name: "libTest",
+		host_supported: true,
 		srcs: ["test.c"],
 		static_libs: ["libFoo"],
 		afdo: true,
@@ -52,12 +53,14 @@ func TestAfdoDeps(t *testing.T) {
 
 	cc_library_static {
 		name: "libFoo",
+		host_supported: true,
 		srcs: ["foo.c"],
 		static_libs: ["libBar"],
 	}
 
 	cc_library_static {
 		name: "libBar",
+		host_supported: true,
 		srcs: ["bar.c"],
 	}
 	`
@@ -210,6 +213,52 @@ func TestAfdoDeps(t *testing.T) {
 		t.Errorf("Expected arm32 'libBar' to enable afdo, but did not find %q in cflags %q", uniqueInternalLinkageNamesCFlag, cFlags)
 	}
 
+	// Verify that the host variants don't enable afdo
+	libTestHost := result.ModuleForTests("libTest", result.Config.BuildOSTarget.String()+"_shared")
+	libFooHost := result.ModuleForTests("libFoo", result.Config.BuildOSTarget.String()+"_static_lto-thin")
+	libBarHost := result.ModuleForTests("libBar", result.Config.BuildOSTarget.String()+"_static_lto-thin")
+
+	cFlags = libTestHost.Rule("cc").Args["cFlags"]
+	if strings.Contains(cFlags, profileSampleCFlag) {
+		t.Errorf("Expected host 'libTest' to not enable afdo profile, but found %q in cflags %q", profileSampleCFlag, cFlags)
+	}
+
+	if strings.Contains(cFlags, uniqueInternalLinkageNamesCFlag) {
+		t.Errorf("Expected host 'libTest' to not enable afdo but found %q in cflags %q",
+			uniqueInternalLinkageNamesCFlag, cFlags)
+	}
+
+	ldFlags = libTestHost.Rule("ld").Args["ldFlags"]
+	if !strings.Contains(ldFlags, noAfdoLtoLdFlag) {
+		t.Errorf("Expected host 'libTest' to not enable afdo, but did not find %q in ldflags %q", noAfdoLtoLdFlag, ldFlags)
+	}
+	if strings.Contains(ldFlags, afdoLtoLdFlag) {
+		t.Errorf("Expected host 'libTest' to not enable afdo, but found %q in ldflags %q", afdoLtoLdFlag, ldFlags)
+	}
+
+	// Check dependency edge from afdo-enabled module to static deps
+	if !hasDirectDep(result, libTestHost.Module(), libFooHost.Module()) {
+		t.Errorf("host libTest missing dependency on non-afdo variant of libFoo")
+	}
+
+	if !hasDirectDep(result, libFooHost.Module(), libBarHost.Module()) {
+		t.Errorf("host libTest missing dependency on non-afdo variant of libBar")
+	}
+
+	cFlags = libFooHost.Rule("cc").Args["cFlags"]
+	if strings.Contains(cFlags, profileSampleCFlag) {
+		t.Errorf("Expected host 'libFoo' to not enable afdo profile, but found %q in cflags %q", uniqueInternalLinkageNamesCFlag, cFlags)
+	}
+	if strings.Contains(cFlags, uniqueInternalLinkageNamesCFlag) {
+		t.Errorf("Expected host 'libFoo' to not enable afdo, but found %q in cflags %q", uniqueInternalLinkageNamesCFlag, cFlags)
+	}
+	cFlags = libBarHost.Rule("cc").Args["cFlags"]
+	if strings.Contains(cFlags, profileSampleCFlag) {
+		t.Errorf("Expected host 'libBar' to not enable afdo profile, but found %q in cflags %q", uniqueInternalLinkageNamesCFlag, cFlags)
+	}
+	if strings.Contains(cFlags, uniqueInternalLinkageNamesCFlag) {
+		t.Errorf("Expected host 'libBar' to not enable afdo, but found %q in cflags %q", uniqueInternalLinkageNamesCFlag, cFlags)
+	}
 }
 
 func TestAfdoEnabledOnStaticDepNoAfdo(t *testing.T) {