cc/builder.go - SHIFTPHONES/android_build_soong - Gitiles

 // Copyright 2015 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

 // This file generates the final rules for compiling all C/C++.  All properties related to
 // compiling should have been translated into builderFlags or another argument to the Transform*
 // functions.

 import (
 	"fmt"
 	"path/filepath"
 	"runtime"
 	"strconv"
 	"strings"

 	"github.com/google/blueprint"

 	"android/soong/android"
 	"android/soong/cc/config"
 )

 const (
 	objectExtension        = ".o"
 	staticLibraryExtension = ".a"
 )

 var (
 	pctx = android.NewPackageContext("android/soong/cc")

 	cc = pctx.AndroidGomaStaticRule("cc",
 		blueprint.RuleParams{
 			Depfile:     "${out}.d",
 			Deps:        blueprint.DepsGCC,
 			Command:     "$relPwd ${config.CcWrapper}$ccCmd -c $cFlags -MD -MF ${out}.d -o $out $in",
 			CommandDeps: []string{"$ccCmd"},
 			Description: "cc $out",
 		},
 		"ccCmd", "cFlags")

 	ld = pctx.AndroidStaticRule("ld",
 		blueprint.RuleParams{
 			Command: "$ldCmd ${crtBegin} @${out}.rsp " +
 				"${libFlags} ${crtEnd} -o ${out} ${ldFlags}",
 			CommandDeps:    []string{"$ldCmd"},
 			Description:    "ld $out",
 			Rspfile:        "${out}.rsp",
 			RspfileContent: "${in}",
 		},
 		"ldCmd", "crtBegin", "libFlags", "crtEnd", "ldFlags")

 	partialLd = pctx.AndroidStaticRule("partialLd",
 		blueprint.RuleParams{
 			Command:     "$ldCmd -nostdlib -Wl,-r ${in} -o ${out} ${ldFlags}",
 			CommandDeps: []string{"$ldCmd"},
 			Description: "partialLd $out",
 		},
 		"ldCmd", "ldFlags")

 	ar = pctx.AndroidStaticRule("ar",
 		blueprint.RuleParams{
 			Command:        "rm -f ${out} && $arCmd $arFlags $out @${out}.rsp",
 			CommandDeps:    []string{"$arCmd"},
 			Description:    "ar $out",
 			Rspfile:        "${out}.rsp",
 			RspfileContent: "${in}",
 		},
 		"arCmd", "arFlags")

 	darwinAr = pctx.AndroidStaticRule("darwinAr",
 		blueprint.RuleParams{
 			Command:     "rm -f ${out} && ${config.MacArPath} $arFlags $out $in",
 			CommandDeps: []string{"${config.MacArPath}"},
 			Description: "ar $out",
 		},
 		"arFlags")

 	darwinAppendAr = pctx.AndroidStaticRule("darwinAppendAr",
 		blueprint.RuleParams{
 			Command:     "cp -f ${inAr} ${out}.tmp && ${config.MacArPath} $arFlags ${out}.tmp $in && mv ${out}.tmp ${out}",
 			CommandDeps: []string{"${config.MacArPath}", "${inAr}"},
 			Description: "ar $out",
 		},
 		"arFlags", "inAr")

 	darwinStrip = pctx.AndroidStaticRule("darwinStrip",
 		blueprint.RuleParams{
 			Command:     "${config.MacStripPath} -u -r -o $out $in",
 			CommandDeps: []string{"${config.MacStripPath}"},
 			Description: "strip $out",
 		})

 	prefixSymbols = pctx.AndroidStaticRule("prefixSymbols",
 		blueprint.RuleParams{
 			Command:     "$objcopyCmd --prefix-symbols=${prefix} ${in} ${out}",
 			CommandDeps: []string{"$objcopyCmd"},
 			Description: "prefixSymbols $out",
 		},
 		"objcopyCmd", "prefix")

 	stripPath = pctx.SourcePathVariable("stripPath", "build/soong/scripts/strip.sh")

 	strip = pctx.AndroidStaticRule("strip",
 		blueprint.RuleParams{
 			Depfile:     "${out}.d",
 			Deps:        blueprint.DepsGCC,
 			Command:     "CROSS_COMPILE=$crossCompile $stripPath ${args} -i ${in} -o ${out} -d ${out}.d",
 			CommandDeps: []string{"$stripPath"},
 			Description: "strip $out",
 		},
 		"args", "crossCompile")

 	emptyFile = pctx.AndroidStaticRule("emptyFile",
 		blueprint.RuleParams{
 			Command:     "rm -f $out && touch $out",
 			Description: "empty file $out",
 		})

 	copyGccLibPath = pctx.SourcePathVariable("copyGccLibPath", "build/soong/scripts/copygcclib.sh")

 	copyGccLib = pctx.AndroidStaticRule("copyGccLib",
 		blueprint.RuleParams{
 			Depfile:     "${out}.d",
 			Deps:        blueprint.DepsGCC,
 			Command:     "$copyGccLibPath $out $ccCmd $cFlags -print-file-name=${libName}",
 			CommandDeps: []string{"$copyGccLibPath", "$ccCmd"},
 			Description: "copy gcc $out",
 		},
 		"ccCmd", "cFlags", "libName")

 	tocPath = pctx.SourcePathVariable("tocPath", "build/soong/scripts/toc.sh")

 	toc = pctx.AndroidStaticRule("toc",
 		blueprint.RuleParams{
 			Depfile:     "${out}.d",
 			Deps:        blueprint.DepsGCC,
 			Command:     "CROSS_COMPILE=$crossCompile $tocPath -i ${in} -o ${out} -d ${out}.d",
 			CommandDeps: []string{"$tocPath"},
 			Restat:      true,
 		},
 		"crossCompile")
 )

 func init() {
 	// We run gcc/clang with PWD=/proc/self/cwd to remove $TOP from the
 	// debug output. That way two builds in two different directories will
 	// create the same output.
 	if runtime.GOOS != "darwin" {
 		pctx.StaticVariable("relPwd", "PWD=/proc/self/cwd")
 	} else {
 		// Darwin doesn't have /proc
 		pctx.StaticVariable("relPwd", "")
 	}
 }

 type builderFlags struct {
 	globalFlags string
 	asFlags     string
 	cFlags      string
 	conlyFlags  string
 	cppFlags    string
 	ldFlags     string
 	libFlags    string
 	yaccFlags   string
 	protoFlags  string
 	toolchain   config.Toolchain
 	clang       bool

 	stripKeepSymbols       bool
 	stripKeepMiniDebugInfo bool
 	stripAddGnuDebuglink   bool
 }

 // Generate rules for compiling multiple .c, .cpp, or .S files to individual .o files
 func TransformSourceToObj(ctx android.ModuleContext, subdir string, srcFiles android.Paths,
 	flags builderFlags, deps android.Paths) (objFiles android.Paths) {

 	objFiles = make(android.Paths, len(srcFiles))

 	cflags := flags.globalFlags + " " + flags.cFlags + " " + flags.conlyFlags
 	cppflags := flags.globalFlags + " " + flags.cFlags + " " + flags.cppFlags
 	asflags := flags.globalFlags + " " + flags.asFlags

 	if flags.clang {
 		cflags += " ${config.NoOverrideClangGlobalCflags}"
 		cppflags += " ${config.NoOverrideClangGlobalCflags}"
 	} else {
 		cflags += " ${config.NoOverrideGlobalCflags}"
 		cppflags += " ${config.NoOverrideGlobalCflags}"
 	}

 	for i, srcFile := range srcFiles {
 		objFile := android.ObjPathWithExt(ctx, srcFile, subdir, "o")

 		objFiles[i] = objFile

 		var moduleCflags string
 		var ccCmd string

 		switch srcFile.Ext() {
 		case ".S", ".s":
 			ccCmd = "gcc"
 			moduleCflags = asflags
 		case ".c":
 			ccCmd = "gcc"
 			moduleCflags = cflags
 		case ".cpp", ".cc":
 			ccCmd = "g++"
 			moduleCflags = cppflags
 		default:
 			ctx.ModuleErrorf("File %s has unknown extension", srcFile)
 			continue
 		}

 		if flags.clang {
 			switch ccCmd {
 			case "gcc":
 				ccCmd = "clang"
 			case "g++":
 				ccCmd = "clang++"
 			default:
 				panic("unrecoginzied ccCmd")
 			}

 			ccCmd = "${config.ClangBin}/" + ccCmd
 		} else {
 			ccCmd = gccCmd(flags.toolchain, ccCmd)
 		}

 		ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 			Rule:      cc,
 			Output:    objFile,
 			Input:     srcFile,
 			OrderOnly: deps,
 			Args: map[string]string{
 				"cFlags": moduleCflags,
 				"ccCmd":  ccCmd,
 			},
 		})
 	}

 	return objFiles
 }

 // Generate a rule for compiling multiple .o files to a static library (.a)
 func TransformObjToStaticLib(ctx android.ModuleContext, objFiles android.Paths,
 	flags builderFlags, outputFile android.ModuleOutPath) {

 	arCmd := gccCmd(flags.toolchain, "ar")
 	arFlags := "crsPD"

 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:   ar,
 		Output: outputFile,
 		Inputs: objFiles,
 		Args: map[string]string{
 			"arFlags": arFlags,
 			"arCmd":   arCmd,
 		},
 	})
 }

 // Generate a rule for compiling multiple .o files to a static library (.a) on
 // darwin.  The darwin ar tool doesn't support @file for list files, and has a
 // very small command line length limit, so we have to split the ar into multiple
 // steps, each appending to the previous one.
 func TransformDarwinObjToStaticLib(ctx android.ModuleContext, objFiles android.Paths,
 	flags builderFlags, outputPath android.ModuleOutPath) {

 	arFlags := "cqs"

 	if len(objFiles) == 0 {
 		dummy := android.PathForModuleOut(ctx, "dummy"+objectExtension)
 		dummyAr := android.PathForModuleOut(ctx, "dummy"+staticLibraryExtension)

 		ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 			Rule:   emptyFile,
 			Output: dummy,
 		})

 		ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 			Rule:   darwinAr,
 			Output: dummyAr,
 			Input:  dummy,
 			Args: map[string]string{
 				"arFlags": arFlags,
 			},
 		})

 		ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 			Rule:   darwinAppendAr,
 			Output: outputPath,
 			Input:  dummy,
 			Args: map[string]string{
 				"arFlags": "d",
 				"inAr":    dummyAr.String(),
 			},
 		})

 		return
 	}

 	// ARG_MAX on darwin is 262144, use half that to be safe
 	objFilesLists, err := splitListForSize(objFiles.Strings(), 131072)
 	if err != nil {
 		ctx.ModuleErrorf("%s", err.Error())
 	}

 	outputFile := outputPath.String()

 	var in, out string
 	for i, l := range objFilesLists {
 		in = out
 		out = outputFile
 		if i != len(objFilesLists)-1 {
 			out += "." + strconv.Itoa(i)
 		}

 		if in == "" {
 			ctx.Build(pctx, blueprint.BuildParams{
 				Rule:    darwinAr,
 				Outputs: []string{out},
 				Inputs:  l,
 				Args: map[string]string{
 					"arFlags": arFlags,
 				},
 			})
 		} else {
 			ctx.Build(pctx, blueprint.BuildParams{
 				Rule:    darwinAppendAr,
 				Outputs: []string{out},
 				Inputs:  l,
 				Args: map[string]string{
 					"arFlags": arFlags,
 					"inAr":    in,
 				},
 			})
 		}
 	}
 }

 // Generate a rule for compiling multiple .o files, plus static libraries, whole static libraries,
 // and shared libraires, to a shared library (.so) or dynamic executable
 func TransformObjToDynamicBinary(ctx android.ModuleContext,
 	objFiles, sharedLibs, staticLibs, lateStaticLibs, wholeStaticLibs, deps android.Paths,
 	crtBegin, crtEnd android.OptionalPath, groupLate bool, flags builderFlags, outputFile android.WritablePath) {

 	var ldCmd string
 	if flags.clang {
 		ldCmd = "${config.ClangBin}/clang++"
 	} else {
 		ldCmd = gccCmd(flags.toolchain, "g++")
 	}

 	var libFlagsList []string

 	if len(flags.libFlags) > 0 {
 		libFlagsList = append(libFlagsList, flags.libFlags)
 	}

 	if len(wholeStaticLibs) > 0 {
 		if ctx.Host() && ctx.Darwin() {
 			libFlagsList = append(libFlagsList, android.JoinWithPrefix(wholeStaticLibs.Strings(), "-force_load "))
 		} else {
 			libFlagsList = append(libFlagsList, "-Wl,--whole-archive ")
 			libFlagsList = append(libFlagsList, wholeStaticLibs.Strings()...)
 			libFlagsList = append(libFlagsList, "-Wl,--no-whole-archive ")
 		}
 	}

 	libFlagsList = append(libFlagsList, staticLibs.Strings()...)

 	if groupLate && !ctx.Darwin() && len(lateStaticLibs) > 0 {
 		libFlagsList = append(libFlagsList, "-Wl,--start-group")
 	}
 	libFlagsList = append(libFlagsList, lateStaticLibs.Strings()...)
 	if groupLate && !ctx.Darwin() && len(lateStaticLibs) > 0 {
 		libFlagsList = append(libFlagsList, "-Wl,--end-group")
 	}

 	for _, lib := range sharedLibs {
 		libFlagsList = append(libFlagsList, lib.String())
 	}

 	deps = append(deps, staticLibs...)
 	deps = append(deps, lateStaticLibs...)
 	deps = append(deps, wholeStaticLibs...)
 	if crtBegin.Valid() {
 		deps = append(deps, crtBegin.Path(), crtEnd.Path())
 	}

 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:      ld,
 		Output:    outputFile,
 		Inputs:    objFiles,
 		Implicits: deps,
 		Args: map[string]string{
 			"ldCmd":    ldCmd,
 			"crtBegin": crtBegin.String(),
 			"libFlags": strings.Join(libFlagsList, " "),
 			"ldFlags":  flags.ldFlags,
 			"crtEnd":   crtEnd.String(),
 		},
 	})
 }

 // Generate a rule for extract a table of contents from a shared library (.so)
 func TransformSharedObjectToToc(ctx android.ModuleContext, inputFile android.WritablePath,
 	outputFile android.WritablePath, flags builderFlags) {

 	crossCompile := gccCmd(flags.toolchain, "")

 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:   toc,
 		Output: outputFile,
 		Input:  inputFile,
 		Args: map[string]string{
 			"crossCompile": crossCompile,
 		},
 	})
 }

 // Generate a rule for compiling multiple .o files to a .o using ld partial linking
 func TransformObjsToObj(ctx android.ModuleContext, objFiles android.Paths,
 	flags builderFlags, outputFile android.WritablePath) {

 	var ldCmd string
 	if flags.clang {
 		ldCmd = "${config.ClangBin}/clang++"
 	} else {
 		ldCmd = gccCmd(flags.toolchain, "g++")
 	}

 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:   partialLd,
 		Output: outputFile,
 		Inputs: objFiles,
 		Args: map[string]string{
 			"ldCmd":   ldCmd,
 			"ldFlags": flags.ldFlags,
 		},
 	})
 }

 // Generate a rule for runing objcopy --prefix-symbols on a binary
 func TransformBinaryPrefixSymbols(ctx android.ModuleContext, prefix string, inputFile android.Path,
 	flags builderFlags, outputFile android.WritablePath) {

 	objcopyCmd := gccCmd(flags.toolchain, "objcopy")

 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:   prefixSymbols,
 		Output: outputFile,
 		Input:  inputFile,
 		Args: map[string]string{
 			"objcopyCmd": objcopyCmd,
 			"prefix":     prefix,
 		},
 	})
 }

 func TransformStrip(ctx android.ModuleContext, inputFile android.Path,
 	outputFile android.WritablePath, flags builderFlags) {

 	crossCompile := gccCmd(flags.toolchain, "")
 	args := ""
 	if flags.stripAddGnuDebuglink {
 		args += " --add-gnu-debuglink"
 	}
 	if flags.stripKeepMiniDebugInfo {
 		args += " --keep-mini-debug-info"
 	}
 	if flags.stripKeepSymbols {
 		args += " --keep-symbols"
 	}

 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:   strip,
 		Output: outputFile,
 		Input:  inputFile,
 		Args: map[string]string{
 			"crossCompile": crossCompile,
 			"args":         args,
 		},
 	})
 }

 func TransformDarwinStrip(ctx android.ModuleContext, inputFile android.Path,
 	outputFile android.WritablePath) {

 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:   darwinStrip,
 		Output: outputFile,
 		Input:  inputFile,
 	})
 }

 func CopyGccLib(ctx android.ModuleContext, libName string,
 	flags builderFlags, outputFile android.WritablePath) {

 	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
 		Rule:   copyGccLib,
 		Output: outputFile,
 		Args: map[string]string{
 			"ccCmd":   gccCmd(flags.toolchain, "gcc"),
 			"cFlags":  flags.globalFlags,
 			"libName": libName,
 		},
 	})
 }

 func gccCmd(toolchain config.Toolchain, cmd string) string {
 	return filepath.Join(toolchain.GccRoot(), "bin", toolchain.GccTriple()+"-"+cmd)
 }

 func splitListForSize(list []string, limit int) (lists [][]string, err error) {
 	var i int

 	start := 0
 	bytes := 0
 	for i = range list {
 		l := len(list[i])
 		if l > limit {
 			return nil, fmt.Errorf("list element greater than size limit (%d)", limit)
 		}
 		if bytes+l > limit {
 			lists = append(lists, list[start:i])
 			start = i
 			bytes = 0
 		}
 		bytes += l + 1 // count a space between each list element
 	}

 	lists = append(lists, list[start:])

 	totalLen := 0
 	for _, l := range lists {
 		totalLen += len(l)
 	}
 	if totalLen != len(list) {
 		panic(fmt.Errorf("Failed breaking up list, %d != %d", len(list), totalLen))
 	}
 	return lists, nil
 }
	// Copyright 2015 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

	// This file generates the final rules for compiling all C/C++. All properties related to
	// compiling should have been translated into builderFlags or another argument to the Transform*
	// functions.

	import (
	"fmt"
	"path/filepath"
	"runtime"
	"strconv"
	"strings"

	"github.com/google/blueprint"

	"android/soong/android"
	"android/soong/cc/config"
	)

	const (
	objectExtension = ".o"
	staticLibraryExtension = ".a"
	)

	var (
	pctx = android.NewPackageContext("android/soong/cc")

	cc = pctx.AndroidGomaStaticRule("cc",
	blueprint.RuleParams{
	Depfile: "${out}.d",
	Deps: blueprint.DepsGCC,
	Command: "$relPwd ${config.CcWrapper}$ccCmd -c $cFlags -MD -MF ${out}.d -o $out $in",
	CommandDeps: []string{"$ccCmd"},
	Description: "cc $out",
	},
	"ccCmd", "cFlags")

	ld = pctx.AndroidStaticRule("ld",
	blueprint.RuleParams{
	Command: "$ldCmd ${crtBegin} @${out}.rsp " +
	"${libFlags} ${crtEnd} -o ${out} ${ldFlags}",
	CommandDeps: []string{"$ldCmd"},
	Description: "ld $out",
	Rspfile: "${out}.rsp",
	RspfileContent: "${in}",
	},
	"ldCmd", "crtBegin", "libFlags", "crtEnd", "ldFlags")

	partialLd = pctx.AndroidStaticRule("partialLd",
	blueprint.RuleParams{
	Command: "$ldCmd -nostdlib -Wl,-r ${in} -o ${out} ${ldFlags}",
	CommandDeps: []string{"$ldCmd"},
	Description: "partialLd $out",
	},
	"ldCmd", "ldFlags")

	ar = pctx.AndroidStaticRule("ar",
	blueprint.RuleParams{
	Command: "rm -f ${out} && $arCmd $arFlags $out @${out}.rsp",
	CommandDeps: []string{"$arCmd"},
	Description: "ar $out",
	Rspfile: "${out}.rsp",
	RspfileContent: "${in}",
	},
	"arCmd", "arFlags")

	darwinAr = pctx.AndroidStaticRule("darwinAr",
	blueprint.RuleParams{
	Command: "rm -f ${out} && ${config.MacArPath} $arFlags $out $in",
	CommandDeps: []string{"${config.MacArPath}"},
	Description: "ar $out",
	},
	"arFlags")

	darwinAppendAr = pctx.AndroidStaticRule("darwinAppendAr",
	blueprint.RuleParams{
	Command: "cp -f ${inAr} ${out}.tmp && ${config.MacArPath} $arFlags ${out}.tmp $in && mv ${out}.tmp ${out}",
	CommandDeps: []string{"${config.MacArPath}", "${inAr}"},
	Description: "ar $out",
	},
	"arFlags", "inAr")

	darwinStrip = pctx.AndroidStaticRule("darwinStrip",
	blueprint.RuleParams{
	Command: "${config.MacStripPath} -u -r -o $out $in",
	CommandDeps: []string{"${config.MacStripPath}"},
	Description: "strip $out",
	})

	prefixSymbols = pctx.AndroidStaticRule("prefixSymbols",
	blueprint.RuleParams{
	Command: "$objcopyCmd --prefix-symbols=${prefix} ${in} ${out}",
	CommandDeps: []string{"$objcopyCmd"},
	Description: "prefixSymbols $out",
	},
	"objcopyCmd", "prefix")

	stripPath = pctx.SourcePathVariable("stripPath", "build/soong/scripts/strip.sh")

	strip = pctx.AndroidStaticRule("strip",
	blueprint.RuleParams{
	Depfile: "${out}.d",
	Deps: blueprint.DepsGCC,
	Command: "CROSS_COMPILE=$crossCompile $stripPath ${args} -i ${in} -o ${out} -d ${out}.d",
	CommandDeps: []string{"$stripPath"},
	Description: "strip $out",
	},
	"args", "crossCompile")

	emptyFile = pctx.AndroidStaticRule("emptyFile",
	blueprint.RuleParams{
	Command: "rm -f $out && touch $out",
	Description: "empty file $out",
	})

	copyGccLibPath = pctx.SourcePathVariable("copyGccLibPath", "build/soong/scripts/copygcclib.sh")

	copyGccLib = pctx.AndroidStaticRule("copyGccLib",
	blueprint.RuleParams{
	Depfile: "${out}.d",
	Deps: blueprint.DepsGCC,
	Command: "$copyGccLibPath $out $ccCmd $cFlags -print-file-name=${libName}",
	CommandDeps: []string{"$copyGccLibPath", "$ccCmd"},
	Description: "copy gcc $out",
	},
	"ccCmd", "cFlags", "libName")

	tocPath = pctx.SourcePathVariable("tocPath", "build/soong/scripts/toc.sh")

	toc = pctx.AndroidStaticRule("toc",
	blueprint.RuleParams{
	Depfile: "${out}.d",
	Deps: blueprint.DepsGCC,
	Command: "CROSS_COMPILE=$crossCompile $tocPath -i ${in} -o ${out} -d ${out}.d",
	CommandDeps: []string{"$tocPath"},
	Restat: true,
	},
	"crossCompile")
	)

	func init() {
	// We run gcc/clang with PWD=/proc/self/cwd to remove $TOP from the
	// debug output. That way two builds in two different directories will
	// create the same output.
	if runtime.GOOS != "darwin" {
	pctx.StaticVariable("relPwd", "PWD=/proc/self/cwd")
	} else {
	// Darwin doesn't have /proc
	pctx.StaticVariable("relPwd", "")
	}
	}

	type builderFlags struct {
	globalFlags string
	asFlags string
	cFlags string
	conlyFlags string
	cppFlags string
	ldFlags string
	libFlags string
	yaccFlags string
	protoFlags string
	toolchain config.Toolchain
	clang bool

	stripKeepSymbols bool
	stripKeepMiniDebugInfo bool
	stripAddGnuDebuglink bool
	}

	// Generate rules for compiling multiple .c, .cpp, or .S files to individual .o files
	func TransformSourceToObj(ctx android.ModuleContext, subdir string, srcFiles android.Paths,
	flags builderFlags, deps android.Paths) (objFiles android.Paths) {

	objFiles = make(android.Paths, len(srcFiles))

	cflags := flags.globalFlags + " " + flags.cFlags + " " + flags.conlyFlags
	cppflags := flags.globalFlags + " " + flags.cFlags + " " + flags.cppFlags
	asflags := flags.globalFlags + " " + flags.asFlags

	if flags.clang {
	cflags += " ${config.NoOverrideClangGlobalCflags}"
	cppflags += " ${config.NoOverrideClangGlobalCflags}"
	} else {
	cflags += " ${config.NoOverrideGlobalCflags}"
	cppflags += " ${config.NoOverrideGlobalCflags}"
	}

	for i, srcFile := range srcFiles {
	objFile := android.ObjPathWithExt(ctx, srcFile, subdir, "o")

	objFiles[i] = objFile

	var moduleCflags string
	var ccCmd string

	switch srcFile.Ext() {
	case ".S", ".s":
	ccCmd = "gcc"
	moduleCflags = asflags
	case ".c":
	ccCmd = "gcc"
	moduleCflags = cflags
	case ".cpp", ".cc":
	ccCmd = "g++"
	moduleCflags = cppflags
	default:
	ctx.ModuleErrorf("File %s has unknown extension", srcFile)
	continue
	}

	if flags.clang {
	switch ccCmd {
	case "gcc":
	ccCmd = "clang"
	case "g++":
	ccCmd = "clang++"
	default:
	panic("unrecoginzied ccCmd")
	}

	ccCmd = "${config.ClangBin}/" + ccCmd
	} else {
	ccCmd = gccCmd(flags.toolchain, ccCmd)
	}

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: cc,
	Output: objFile,
	Input: srcFile,
	OrderOnly: deps,
	Args: map[string]string{
	"cFlags": moduleCflags,
	"ccCmd": ccCmd,
	},
	})
	}

	return objFiles
	}

	// Generate a rule for compiling multiple .o files to a static library (.a)
	func TransformObjToStaticLib(ctx android.ModuleContext, objFiles android.Paths,
	flags builderFlags, outputFile android.ModuleOutPath) {

	arCmd := gccCmd(flags.toolchain, "ar")
	arFlags := "crsPD"

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: ar,
	Output: outputFile,
	Inputs: objFiles,
	Args: map[string]string{
	"arFlags": arFlags,
	"arCmd": arCmd,
	},
	})
	}

	// Generate a rule for compiling multiple .o files to a static library (.a) on
	// darwin. The darwin ar tool doesn't support @file for list files, and has a
	// very small command line length limit, so we have to split the ar into multiple
	// steps, each appending to the previous one.
	func TransformDarwinObjToStaticLib(ctx android.ModuleContext, objFiles android.Paths,
	flags builderFlags, outputPath android.ModuleOutPath) {

	arFlags := "cqs"

	if len(objFiles) == 0 {
	dummy := android.PathForModuleOut(ctx, "dummy"+objectExtension)
	dummyAr := android.PathForModuleOut(ctx, "dummy"+staticLibraryExtension)

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: emptyFile,
	Output: dummy,
	})

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: darwinAr,
	Output: dummyAr,
	Input: dummy,
	Args: map[string]string{
	"arFlags": arFlags,
	},
	})

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: darwinAppendAr,
	Output: outputPath,
	Input: dummy,
	Args: map[string]string{
	"arFlags": "d",
	"inAr": dummyAr.String(),
	},
	})

	return
	}

	// ARG_MAX on darwin is 262144, use half that to be safe
	objFilesLists, err := splitListForSize(objFiles.Strings(), 131072)
	if err != nil {
	ctx.ModuleErrorf("%s", err.Error())
	}

	outputFile := outputPath.String()

	var in, out string
	for i, l := range objFilesLists {
	in = out
	out = outputFile
	if i != len(objFilesLists)-1 {
	out += "." + strconv.Itoa(i)
	}

	if in == "" {
	ctx.Build(pctx, blueprint.BuildParams{
	Rule: darwinAr,
	Outputs: []string{out},
	Inputs: l,
	Args: map[string]string{
	"arFlags": arFlags,
	},
	})
	} else {
	ctx.Build(pctx, blueprint.BuildParams{
	Rule: darwinAppendAr,
	Outputs: []string{out},
	Inputs: l,
	Args: map[string]string{
	"arFlags": arFlags,
	"inAr": in,
	},
	})
	}
	}
	}

	// Generate a rule for compiling multiple .o files, plus static libraries, whole static libraries,
	// and shared libraires, to a shared library (.so) or dynamic executable
	func TransformObjToDynamicBinary(ctx android.ModuleContext,
	objFiles, sharedLibs, staticLibs, lateStaticLibs, wholeStaticLibs, deps android.Paths,
	crtBegin, crtEnd android.OptionalPath, groupLate bool, flags builderFlags, outputFile android.WritablePath) {

	var ldCmd string
	if flags.clang {
	ldCmd = "${config.ClangBin}/clang++"
	} else {
	ldCmd = gccCmd(flags.toolchain, "g++")
	}

	var libFlagsList []string

	if len(flags.libFlags) > 0 {
	libFlagsList = append(libFlagsList, flags.libFlags)
	}

	if len(wholeStaticLibs) > 0 {
	if ctx.Host() && ctx.Darwin() {
	libFlagsList = append(libFlagsList, android.JoinWithPrefix(wholeStaticLibs.Strings(), "-force_load "))
	} else {
	libFlagsList = append(libFlagsList, "-Wl,--whole-archive ")
	libFlagsList = append(libFlagsList, wholeStaticLibs.Strings()...)
	libFlagsList = append(libFlagsList, "-Wl,--no-whole-archive ")
	}
	}

	libFlagsList = append(libFlagsList, staticLibs.Strings()...)

	if groupLate && !ctx.Darwin() && len(lateStaticLibs) > 0 {
	libFlagsList = append(libFlagsList, "-Wl,--start-group")
	}
	libFlagsList = append(libFlagsList, lateStaticLibs.Strings()...)
	if groupLate && !ctx.Darwin() && len(lateStaticLibs) > 0 {
	libFlagsList = append(libFlagsList, "-Wl,--end-group")
	}

	for _, lib := range sharedLibs {
	libFlagsList = append(libFlagsList, lib.String())
	}

	deps = append(deps, staticLibs...)
	deps = append(deps, lateStaticLibs...)
	deps = append(deps, wholeStaticLibs...)
	if crtBegin.Valid() {
	deps = append(deps, crtBegin.Path(), crtEnd.Path())
	}

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: ld,
	Output: outputFile,
	Inputs: objFiles,
	Implicits: deps,
	Args: map[string]string{
	"ldCmd": ldCmd,
	"crtBegin": crtBegin.String(),
	"libFlags": strings.Join(libFlagsList, " "),
	"ldFlags": flags.ldFlags,
	"crtEnd": crtEnd.String(),
	},
	})
	}

	// Generate a rule for extract a table of contents from a shared library (.so)
	func TransformSharedObjectToToc(ctx android.ModuleContext, inputFile android.WritablePath,
	outputFile android.WritablePath, flags builderFlags) {

	crossCompile := gccCmd(flags.toolchain, "")

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: toc,
	Output: outputFile,
	Input: inputFile,
	Args: map[string]string{
	"crossCompile": crossCompile,
	},
	})
	}

	// Generate a rule for compiling multiple .o files to a .o using ld partial linking
	func TransformObjsToObj(ctx android.ModuleContext, objFiles android.Paths,
	flags builderFlags, outputFile android.WritablePath) {

	var ldCmd string
	if flags.clang {
	ldCmd = "${config.ClangBin}/clang++"
	} else {
	ldCmd = gccCmd(flags.toolchain, "g++")
	}

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: partialLd,
	Output: outputFile,
	Inputs: objFiles,
	Args: map[string]string{
	"ldCmd": ldCmd,
	"ldFlags": flags.ldFlags,
	},
	})
	}

	// Generate a rule for runing objcopy --prefix-symbols on a binary
	func TransformBinaryPrefixSymbols(ctx android.ModuleContext, prefix string, inputFile android.Path,
	flags builderFlags, outputFile android.WritablePath) {

	objcopyCmd := gccCmd(flags.toolchain, "objcopy")

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: prefixSymbols,
	Output: outputFile,
	Input: inputFile,
	Args: map[string]string{
	"objcopyCmd": objcopyCmd,
	"prefix": prefix,
	},
	})
	}

	func TransformStrip(ctx android.ModuleContext, inputFile android.Path,
	outputFile android.WritablePath, flags builderFlags) {

	crossCompile := gccCmd(flags.toolchain, "")
	args := ""
	if flags.stripAddGnuDebuglink {
	args += " --add-gnu-debuglink"
	}
	if flags.stripKeepMiniDebugInfo {
	args += " --keep-mini-debug-info"
	}
	if flags.stripKeepSymbols {
	args += " --keep-symbols"
	}

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: strip,
	Output: outputFile,
	Input: inputFile,
	Args: map[string]string{
	"crossCompile": crossCompile,
	"args": args,
	},
	})
	}

	func TransformDarwinStrip(ctx android.ModuleContext, inputFile android.Path,
	outputFile android.WritablePath) {

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: darwinStrip,
	Output: outputFile,
	Input: inputFile,
	})
	}

	func CopyGccLib(ctx android.ModuleContext, libName string,
	flags builderFlags, outputFile android.WritablePath) {

	ctx.ModuleBuild(pctx, android.ModuleBuildParams{
	Rule: copyGccLib,
	Output: outputFile,
	Args: map[string]string{
	"ccCmd": gccCmd(flags.toolchain, "gcc"),
	"cFlags": flags.globalFlags,
	"libName": libName,
	},
	})
	}

	func gccCmd(toolchain config.Toolchain, cmd string) string {
	return filepath.Join(toolchain.GccRoot(), "bin", toolchain.GccTriple()+"-"+cmd)
	}

	func splitListForSize(list []string, limit int) (lists [][]string, err error) {
	var i int

	start := 0
	bytes := 0
	for i = range list {
	l := len(list[i])
	if l > limit {
	return nil, fmt.Errorf("list element greater than size limit (%d)", limit)
	}
	if bytes+l > limit {
	lists = append(lists, list[start:i])
	start = i
	bytes = 0
	}
	bytes += l + 1 // count a space between each list element
	}

	lists = append(lists, list[start:])

	totalLen := 0
	for _, l := range lists {
	totalLen += len(l)
	}
	if totalLen != len(list) {
	panic(fmt.Errorf("Failed breaking up list, %d != %d", len(list), totalLen))
	}
	return lists, nil
	}