bloaty/bloaty.go

// Copyright 2021 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Package bloaty implements a singleton that measures binary (e.g. ELF
// executable, shared library or Rust rlib) section sizes at build time.
package bloaty

import (
	"android/soong/android"

	"github.com/google/blueprint"
)

const bloatyDescriptorExt = "bloaty.csv"

var (
	fileSizeMeasurerKey blueprint.ProviderKey
	pctx                = android.NewPackageContext("android/soong/bloaty")

	// bloaty is used to measure a binary section sizes.
	bloaty = pctx.AndroidStaticRule("bloaty",
		blueprint.RuleParams{
			Command:     "${bloaty} -n 0 --csv ${in} > ${out}",
			CommandDeps: []string{"${bloaty}"},
		})

	// The bloaty merger script is used to combine the outputs from bloaty
	// into a single protobuf.
	bloatyMerger = pctx.AndroidStaticRule("bloatyMerger",
		blueprint.RuleParams{
			Command:        "${bloatyMerger} ${out}.lst ${out}",
			CommandDeps:    []string{"${bloatyMerger}"},
			Rspfile:        "${out}.lst",
			RspfileContent: "${in}",
		})
)

func init() {
	pctx.VariableConfigMethod("hostPrebuiltTag", android.Config.PrebuiltOS)
	pctx.SourcePathVariable("bloaty", "prebuilts/build-tools/${hostPrebuiltTag}/bin/bloaty")
	pctx.HostBinToolVariable("bloatyMerger", "bloaty_merger")
	android.RegisterSingletonType("file_metrics", fileSizesSingleton)
	fileSizeMeasurerKey = blueprint.NewProvider(android.ModuleOutPath{})
}

// MeasureSizeForPath should be called by binary producers (e.g. in builder.go).
func MeasureSizeForPath(ctx android.ModuleContext, filePath android.WritablePath) {
	ctx.SetProvider(fileSizeMeasurerKey, filePath)
}

type sizesSingleton struct{}

func fileSizesSingleton() android.Singleton {
	return &sizesSingleton{}
}

func (singleton *sizesSingleton) GenerateBuildActions(ctx android.SingletonContext) {
	var deps android.Paths
	// Visit all modules. If the size provider give us a binary path to measure,
	// create the rule to measure it.
	ctx.VisitAllModules(func(m android.Module) {
		if !ctx.ModuleHasProvider(m, fileSizeMeasurerKey) {
			return
		}
		filePath := ctx.ModuleProvider(m, fileSizeMeasurerKey).(android.ModuleOutPath)
		sizeFile := filePath.ReplaceExtension(ctx, bloatyDescriptorExt)
		ctx.Build(pctx, android.BuildParams{
			Rule:        bloaty,
			Description: "bloaty " + filePath.Rel(),
			Input:       filePath,
			Output:      sizeFile,
		})
		deps = append(deps, sizeFile)
	})

	ctx.Build(pctx, android.BuildParams{
		Rule:   bloatyMerger,
		Inputs: android.SortedUniquePaths(deps),
		Output: android.PathForOutput(ctx, "binary_sizes.pb"),
	})
}