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author | Pirama Arumuga Nainar <pirama@google.com> | 2017-08-31 23:38:27 -0700 |
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committer | Pirama Arumuga Nainar <pirama@google.com> | 2017-09-21 12:37:19 -0700 |
commit | ada83ec0a6dc677cffd0d29c10b48cbda477daf7 (patch) | |
tree | 5be48add3d9c89ce7c5b4e615642812f5aa7bb01 /cc/pgo.go | |
parent | d685385c6baf385c1d87bfa92dcd0f824a2cb09f (diff) | |
download | build_soong-ada83ec0a6dc677cffd0d29c10b48cbda477daf7.tar.gz build_soong-ada83ec0a6dc677cffd0d29c10b48cbda477daf7.tar.bz2 build_soong-ada83ec0a6dc677cffd0d29c10b48cbda477daf7.zip |
Add PGO support to soong
Bug: http://b/63768402
Bug: http://b/65598278
Add support for the 'pgo' property to specify how a module is processed
under PGO. A sample property is below:
pgo: {
instrumentation: true, // could be "sampling: true" when supported
profile_file: "pgo_simple.profdata",
benchmarks: ["pgo_simple"],
}
1. Runtime profiles can be gathered using "sampling" or
"instrumentation". Sampling is not supported initially.
2. If 'toolchain/pgo-profiles' project is found,
'toolchain/pgo-profiles/${profile_file}' is passed to the compiler and
linker when building this module.
3. If ANDROID_PGO_INSTRUMENT environment variable is set, and includes a
benchmark in the 'benchmarks' list, appropriate flags (for e.g.
-fprofile-generate for instrumentation) are passed to the compiler and
linker when building this module.
Test: Add example modules that specify the pgo property and verify
appropriate flags and dependencies in the Ninja file. Some
tests/examples are in https://android-review.googlesource.com/474805
Change-Id: I6242e0c904497a115e367dea6927ba1c4b906355
Diffstat (limited to 'cc/pgo.go')
-rw-r--r-- | cc/pgo.go | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/cc/pgo.go b/cc/pgo.go new file mode 100644 index 00000000..ccddece9 --- /dev/null +++ b/cc/pgo.go @@ -0,0 +1,190 @@ +// Copyright 2017 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 cc + +import ( + "fmt" + "strings" + + "android/soong/android" +) + +var ( + // Add flags to ignore warnings that profiles are old or missing for + // some functions + profileUseOtherFlags = []string{} +) + +const pgoProfileProject = "toolchain/pgo-profiles" + +const profileInstrumentFlag = "-fprofile-generate=/data/local/tmp" +const profileSamplingFlag = "-gline-tables-only" +const profileUseInstrumentFormat = "-fprofile-use=%s" +const profileUseSamplingFormat = "-fprofile-sample-use=%s" + +type PgoProperties struct { + Pgo struct { + Instrumentation *bool + Sampling *bool + Profile_file *string `android:"arch_variant"` + Benchmarks []string + } `android:"arch_variant"` + + PgoPresent bool `blueprint:"mutated"` + ShouldProfileModule bool `blueprint:"mutated"` +} + +type pgo struct { + Properties PgoProperties +} + +func (pgo *pgo) props() []interface{} { + return []interface{}{&pgo.Properties} +} + +func (pgo *pgo) profileGatherFlags(ctx ModuleContext) string { + if *pgo.Properties.Pgo.Instrumentation { + return profileInstrumentFlag + } + if *pgo.Properties.Pgo.Sampling { + return profileSamplingFlag + } + return "" +} + +func (pgo *pgo) profileUseFlag(ctx ModuleContext, file string) string { + if *pgo.Properties.Pgo.Instrumentation { + return fmt.Sprintf(profileUseInstrumentFormat, file) + } + if *pgo.Properties.Pgo.Sampling { + return fmt.Sprintf(profileUseSamplingFormat, file) + } + return "" +} + +func (pgo *pgo) profileUseFlags(ctx ModuleContext, file string) []string { + flags := []string{pgo.profileUseFlag(ctx, file)} + flags = append(flags, profileUseOtherFlags...) + return flags +} + +func (props *PgoProperties) isPGO(ctx BaseModuleContext) bool { + isInstrumentation := props.Pgo.Instrumentation != nil + isSampling := props.Pgo.Sampling != nil + + profileKindPresent := isInstrumentation || isSampling + filePresent := props.Pgo.Profile_file != nil + benchmarksPresent := len(props.Pgo.Benchmarks) > 0 + + // If all three properties are absent, PGO is OFF for this module + if !profileKindPresent && !filePresent && !benchmarksPresent { + return false + } + + // If at least one property exists, validate that all properties exist + if !profileKindPresent || !filePresent || !benchmarksPresent { + var missing []string + if !profileKindPresent { + missing = append(missing, "profile kind (either \"instrumentation\" or \"sampling\" property)") + } + if !filePresent { + missing = append(missing, "profile_file property") + } + if !benchmarksPresent { + missing = append(missing, "non-empty benchmarks property") + } + missingProps := strings.Join(missing, ", ") + ctx.ModuleErrorf("PGO specification is missing properties: " + missingProps) + } + + // Sampling not supported yet + // + // TODO When sampling support is turned on, check that instrumentation and + // sampling are not simultaneously specified + if isSampling { + ctx.PropertyErrorf("pgo.sampling", "\"sampling\" is not supported yet)") + } + + return true +} + +func getPgoProfilesDir(ctx ModuleContext) android.OptionalPath { + return android.ExistentPathForSource(ctx, "", pgoProfileProject) +} + +func (pgo *pgo) begin(ctx BaseModuleContext) { + // TODO Evaluate if we need to support PGO for host modules + if ctx.Host() { + return + } + + // Check if PGO is needed for this module + pgo.Properties.PgoPresent = pgo.Properties.isPGO(ctx) + + if !pgo.Properties.PgoPresent { + return + } + + // This module should be instrumented if ANDROID_PGO_INSTRUMENT is set + // and includes a benchmark listed for this module + // + // TODO Validate that each benchmark instruments at least one module + pgo.Properties.ShouldProfileModule = false + pgoBenchmarks := ctx.AConfig().Getenv("ANDROID_PGO_INSTRUMENT") + pgoBenchmarksMap := make(map[string]bool) + for _, b := range strings.Split(pgoBenchmarks, ",") { + pgoBenchmarksMap[b] = true + } + + for _, b := range pgo.Properties.Pgo.Benchmarks { + if pgoBenchmarksMap[b] == true { + pgo.Properties.ShouldProfileModule = true + break + } + } +} + +func (pgo *pgo) flags(ctx ModuleContext, flags Flags) Flags { + if ctx.Host() { + return flags + } + + props := pgo.Properties + + // Add flags to profile this module based on its profile_kind + if props.ShouldProfileModule { + profileGatherFlags := pgo.profileGatherFlags(ctx) + flags.LdFlags = append(flags.LdFlags, profileGatherFlags) + flags.CFlags = append(flags.CFlags, profileGatherFlags) + return flags + } + + // If the PGO profiles project is found, and this module has PGO + // enabled, add flags to use the profile + if profilesDir := getPgoProfilesDir(ctx); props.PgoPresent && profilesDir.Valid() { + profileFile := android.PathForSource(ctx, profilesDir.String(), *(props.Pgo.Profile_file)) + profileUseFlags := pgo.profileUseFlags(ctx, profileFile.String()) + + flags.CFlags = append(flags.CFlags, profileUseFlags...) + flags.LdFlags = append(flags.LdFlags, profileUseFlags...) + + // Update CFlagsDeps and LdFlagsDeps so the module is rebuilt + // if profileFile gets updated + flags.CFlagsDeps = append(flags.CFlagsDeps, profileFile) + flags.LdFlagsDeps = append(flags.LdFlagsDeps, profileFile) + } + + return flags +} |