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Commit 1150fd7c authored by Pirama Arumuga Nainar's avatar Pirama Arumuga Nainar
Browse files

Propagate PGO instr. flags to dependencies of a static lib 

Bug: http://b/119560349
Bug: http://b/168925229

To build with PGO instrumentation, the link step also needs
-fprofile-generate flag.  Omitting this will result in a linker error.
This surfaces if module A depends on module B but PGO is used only for
module B.

Previous uses of PGO were avoiding or working around the issue but to
accommadate recent changes, this CL propagates the PGO linker flag to
module A.

Test: pgo-coral-config1 in release branch, TH
Change-Id: I12f6243152d4f5ea5526fbce03c25dba232ddab7
parent ca4536fc

cc/pgo.go

+43 −9
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ type PgoProperties struct { 
	PgoPresent          bool `blueprint:"mutated"`

	ShouldProfileModule bool `blueprint:"mutated"`

	PgoCompile          bool `blueprint:"mutated"`

	PgoInstrLink        bool `blueprint:"mutated"`

}



type pgo struct {
@@ -89,13 +90,12 @@ func (pgo *pgo) props() []interface{} { 
}



func (props *PgoProperties) addInstrumentationProfileGatherFlags(ctx ModuleContext, flags Flags) Flags {

	// Add to C flags iff PGO is explicitly enabled for this module.

	if props.ShouldProfileModule {

		flags.Local.CFlags = append(flags.Local.CFlags, props.Pgo.Cflags...)



		flags.Local.CFlags = append(flags.Local.CFlags, profileInstrumentFlag)

	// The profile runtime is added below in deps().  Add the below

	// flag, which is the only other link-time action performed by

	// the Clang driver during link.

	flags.Local.LdFlags = append(flags.Local.LdFlags, "-u__llvm_profile_runtime")

	}

	flags.Local.LdFlags = append(flags.Local.LdFlags, profileInstrumentFlag)

	return flags

}

func (props *PgoProperties) addSamplingProfileGatherFlags(ctx ModuleContext, flags Flags) Flags {
@@ -250,10 +250,12 @@ func (pgo *pgo) begin(ctx BaseModuleContext) { 


	if pgoBenchmarksMap["all"] == true || pgoBenchmarksMap["ALL"] == true {

		pgo.Properties.ShouldProfileModule = true

		pgo.Properties.PgoInstrLink = pgo.Properties.isInstrumentation()

	} else {

		for _, b := range pgo.Properties.Pgo.Benchmarks {

			if pgoBenchmarksMap[b] == true {

				pgo.Properties.ShouldProfileModule = true

				pgo.Properties.PgoInstrLink = pgo.Properties.isInstrumentation()

				break

			}

		}
@@ -286,10 +288,42 @@ func (pgo *pgo) flags(ctx ModuleContext, flags Flags) Flags { 
		return flags

	}



	props := pgo.Properties

	// Deduce PgoInstrLink property i.e. whether this module needs to be

	// linked with profile-generation flags.  Here, we're setting it if any

	// dependency needs PGO instrumentation.  It is initially set in

	// begin() if PGO is directly enabled for this module.

	if ctx.static() && !ctx.staticBinary() {

		// For static libraries, check if any whole_static_libs are

		// linked with profile generation

		ctx.VisitDirectDeps(func(m android.Module) {

			if depTag, ok := ctx.OtherModuleDependencyTag(m).(libraryDependencyTag); ok {

				if depTag.static() && depTag.wholeStatic {

					if cc, ok := m.(*Module); ok {

						if cc.pgo.Properties.PgoInstrLink {

							pgo.Properties.PgoInstrLink = true

						}

					}

				}

			}

		})

	} else {

		// For executables and shared libraries, check all static dependencies.

		ctx.VisitDirectDeps(func(m android.Module) {

			if depTag, ok := ctx.OtherModuleDependencyTag(m).(libraryDependencyTag); ok {

				if depTag.static() {

					if cc, ok := m.(*Module); ok {

						if cc.pgo.Properties.PgoInstrLink {

							pgo.Properties.PgoInstrLink = true

						}

					}

				}

			}

		})

	}



	props := pgo.Properties

	// Add flags to profile this module based on its profile_kind

	if props.ShouldProfileModule && props.isInstrumentation() {

	if (props.ShouldProfileModule && props.isInstrumentation()) || props.PgoInstrLink {

		// Instrumentation PGO use and gather flags cannot coexist.

		return props.addInstrumentationProfileGatherFlags(ctx, flags)

	} else if props.ShouldProfileModule && props.isSampling() {