Add pprof labels

Add pprof labels to the larger stages of blueprint, including
labels for each mutator.

Change-Id: Ie91daff51811187c1b702a775c05d0b32f7170fc

context.go

@@ -16,6 +16,7 @@ package blueprint
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -24,6 +25,7 @@ import (
 	"path/filepath"
 	"reflect"
 	"runtime"
+	"runtime/pprof"
 	"sort"
 	"strings"
 	"sync"
@@ -66,6 +68,8 @@ const MockModuleListFile = "bplist"
 // write phase generates the Ninja manifest text based on the generated build
 // actions.
 type Context struct {
+	context.Context
+
 	// set at instantiation
 	moduleFactories     map[string]ModuleFactory
 	nameInterface       NameInterface
@@ -275,6 +279,7 @@ type mutatorInfo struct {
 
 func newContext() *Context {
 	return &Context{
+		Context:            context.Background(),
 		moduleFactories:    make(map[string]ModuleFactory),
 		nameInterface:      NewSimpleNameInterface(),
 		moduleInfo:         make(map[Module]*moduleInfo),
@@ -1329,27 +1334,39 @@ func (c *Context) addModule(module *moduleInfo) []error {
 // the modules depended upon are defined and that no circular dependencies
 // exist.
 func (c *Context) ResolveDependencies(config interface{}) (deps []string, errs []error) {
+	return c.resolveDependencies(c.Context, config)
+}
+
+func (c *Context) resolveDependencies(ctx context.Context, config interface{}) (deps []string, errs []error) {
+	pprof.Do(ctx, pprof.Labels("blueprint", "ResolveDependencies"), func(ctx context.Context) {
 		c.liveGlobals = newLiveTracker(config)
 
 		deps, errs = c.generateSingletonBuildActions(config, c.preSingletonInfo, c.liveGlobals)
 		if len(errs) > 0 {
-		return nil, errs
+			return
 		}
 
 		errs = c.updateDependencies()
 		if len(errs) > 0 {
-		return nil, errs
+			return
 		}
 
-	mutatorDeps, errs := c.runMutators(config)
+		var mutatorDeps []string
+		mutatorDeps, errs = c.runMutators(ctx, config)
 		if len(errs) > 0 {
-		return nil, errs
+			return
 		}
 		deps = append(deps, mutatorDeps...)
 
 		c.cloneModules()
 
 		c.dependenciesReady = true
+	})
+
+	if len(errs) > 0 {
+		return nil, errs
+	}
+
 	return deps, nil
 }
 
@@ -1863,31 +1880,39 @@ func (c *Context) updateDependencies() (errs []error) {
 // SingletonContext.AddNinjaFileDeps(), and PackageContext.AddNinjaFileDeps()
 // methods.
 func (c *Context) PrepareBuildActions(config interface{}) (deps []string, errs []error) {
+	pprof.Do(c.Context, pprof.Labels("blueprint", "PrepareBuildActions"), func(ctx context.Context) {
 		c.buildActionsReady = false
 
 		if !c.dependenciesReady {
-		extraDeps, errs := c.ResolveDependencies(config)
+			var extraDeps []string
+			extraDeps, errs = c.resolveDependencies(ctx, config)
 			if len(errs) > 0 {
-			return nil, errs
+				return
 			}
 			deps = append(deps, extraDeps...)
 		}
 
-	depsModules, errs := c.generateModuleBuildActions(config, c.liveGlobals)
+		var depsModules []string
+		depsModules, errs = c.generateModuleBuildActions(config, c.liveGlobals)
 		if len(errs) > 0 {
-		return nil, errs
+			return
 		}
 
-	depsSingletons, errs := c.generateSingletonBuildActions(config, c.singletonInfo, c.liveGlobals)
+		var depsSingletons []string
+		depsSingletons, errs = c.generateSingletonBuildActions(config, c.singletonInfo, c.liveGlobals)
 		if len(errs) > 0 {
-		return nil, errs
+			return
 		}
 
 		deps = append(deps, depsModules...)
 		deps = append(deps, depsSingletons...)
 
 		if c.ninjaBuildDir != nil {
-		c.liveGlobals.addNinjaStringDeps(c.ninjaBuildDir)
+			err := c.liveGlobals.addNinjaStringDeps(c.ninjaBuildDir)
+			if err != nil {
+				errs = []error{err}
+				return
+			}
 		}
 
 		pkgNames, depsPackages := c.makeUniquePackageNames(c.liveGlobals)
@@ -1903,17 +1928,24 @@ func (c *Context) PrepareBuildActions(config interface{}) (deps []string, errs [
 		c.globalRules = c.liveGlobals.rules
 
 		c.buildActionsReady = true
+	})
+
+	if len(errs) > 0 {
+		return nil, errs
+	}
 
 	return deps, nil
 }
 
-func (c *Context) runMutators(config interface{}) (deps []string, errs []error) {
+func (c *Context) runMutators(ctx context.Context, config interface{}) (deps []string, errs []error) {
 	var mutators []*mutatorInfo
 
+	pprof.Do(ctx, pprof.Labels("blueprint", "runMutators"), func(ctx context.Context) {
 		mutators = append(mutators, c.earlyMutatorInfo...)
 		mutators = append(mutators, c.mutatorInfo...)
 
 		for _, mutator := range mutators {
+			pprof.Do(ctx, pprof.Labels("mutator", mutator.name), func(context.Context) {
 				var newDeps []string
 				if mutator.topDownMutator != nil {
 					newDeps, errs = c.runMutator(config, mutator, topDownMutator)
@@ -1923,9 +1955,18 @@ func (c *Context) runMutators(config interface{}) (deps []string, errs []error)
 					panic("no mutator set on " + mutator.name)
 				}
 				if len(errs) > 0 {
-			return nil, errs
+					return
 				}
 				deps = append(deps, newDeps...)
+			})
+			if len(errs) > 0 {
+				return
+			}
+		}
+	})
+
+	if len(errs) > 0 {
+		return nil, errs
 	}
 
 	return deps, nil
@@ -2932,55 +2973,63 @@ func (c *Context) VisitAllModuleVariants(module Module,
 // actions to w.  If this is called before PrepareBuildActions successfully
 // completes then ErrBuildActionsNotReady is returned.
 func (c *Context) WriteBuildFile(w io.Writer) error {
+	var err error
+	pprof.Do(c.Context, pprof.Labels("blueprint", "WriteBuildFile"), func(ctx context.Context) {
 		if !c.buildActionsReady {
-		return ErrBuildActionsNotReady
+			err = ErrBuildActionsNotReady
+			return
 		}
 
 		nw := newNinjaWriter(w)
 
-	err := c.writeBuildFileHeader(nw)
+		err = c.writeBuildFileHeader(nw)
 		if err != nil {
-		return err
+			return
 		}
 
 		err = c.writeNinjaRequiredVersion(nw)
 		if err != nil {
-		return err
+			return
 		}
 
 		err = c.writeSubninjas(nw)
 		if err != nil {
-		return err
+			return
 		}
 
 		// TODO: Group the globals by package.
 
 		err = c.writeGlobalVariables(nw)
 		if err != nil {
-		return err
+			return
 		}
 
 		err = c.writeGlobalPools(nw)
 		if err != nil {
-		return err
+			return
 		}
 
 		err = c.writeBuildDir(nw)
 		if err != nil {
-		return err
+			return
 		}
 
 		err = c.writeGlobalRules(nw)
 		if err != nil {
-		return err
+			return
 		}
 
 		err = c.writeAllModuleActions(nw)
 		if err != nil {
-		return err
+			return
 		}
 
 		err = c.writeAllSingletonActions(nw)
+		if err != nil {
+			return
+		}
+	})
+
 	if err != nil {
 		return err
 	}