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// Copyright 2016 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 (
"android/soong/android"
"android/soong/cc/config"
"fmt"
"strconv"
"github.com/google/blueprint"
"github.com/google/blueprint/proptools"
)
// This file contains the basic functionality for linking against static libraries and shared
// libraries. Final linking into libraries or executables is handled in library.go, binary.go, etc.
type BaseLinkerProperties struct {
// list of modules whose object files should be linked into this module
// in their entirety. For static library modules, all of the .o files from the intermediate
// directory of the dependency will be linked into this modules .a file. For a shared library,
// the dependency's .a file will be linked into this module using -Wl,--whole-archive.
Whole_static_libs []string `android:"arch_variant,variant_prepend"`
// list of modules that should be statically linked into this module.
Static_libs []string `android:"arch_variant,variant_prepend"`
// list of modules that should be dynamically linked into this module.
Shared_libs []string `android:"arch_variant"`
// list of modules that should only provide headers for this module.
Header_libs []string `android:"arch_variant,variant_prepend"`
// list of module-specific flags that will be used for all link steps
Ldflags []string `android:"arch_variant"`
// list of system libraries that will be dynamically linked to
// shared library and executable modules. If unset, generally defaults to libc,
// libm, and libdl. Set to [] to prevent linking against the defaults.
System_shared_libs []string `android:"arch_variant"`
// allow the module to contain undefined symbols. By default,
// modules cannot contain undefined symbols that are not satisified by their immediate
// dependencies. Set this flag to true to remove --no-undefined from the linker flags.
// This flag should only be necessary for compiling low-level libraries like libc.
Allow_undefined_symbols *bool `android:"arch_variant"`
// don't link in libclang_rt.builtins-*.a
No_libcrt *bool `android:"arch_variant"`
// Use clang lld instead of gnu ld.
Use_clang_lld *bool `android:"arch_variant"`
// -l arguments to pass to linker for host-provided shared libraries
Host_ldlibs []string `android:"arch_variant"`
// list of shared libraries to re-export include directories from. Entries must be
// present in shared_libs.
Export_shared_lib_headers []string `android:"arch_variant"`
// list of static libraries to re-export include directories from. Entries must be
// present in static_libs.
Export_static_lib_headers []string `android:"arch_variant"`
// list of header libraries to re-export include directories from. Entries must be
// present in header_libs.
Export_header_lib_headers []string `android:"arch_variant"`
// list of generated headers to re-export include directories from. Entries must be
// present in generated_headers.
Export_generated_headers []string `android:"arch_variant"`
// don't link in crt_begin and crt_end. This flag should only be necessary for
// compiling crt or libc.
Nocrt *bool `android:"arch_variant"`
// group static libraries. This can resolve missing symbols issues with interdependencies
// between static libraries, but it is generally better to order them correctly instead.
Group_static_libs *bool `android:"arch_variant"`
// list of modules that should be installed with this module. This is similar to 'required'
// but '.vendor' suffix will be appended to the module names if the shared libraries have
// vendor variants and this module uses VNDK.
Runtime_libs []string `android:"arch_variant"`
Target struct {
Vendor struct {
// list of shared libs that only should be used to build the vendor
// variant of the C/C++ module.
Shared_libs []string
// list of shared libs that should not be used to build the vendor variant
// of the C/C++ module.
Exclude_shared_libs []string
// list of static libs that should not be used to build the vendor variant
// of the C/C++ module.
Exclude_static_libs []string
// list of header libs that should not be used to build the vendor variant
// of the C/C++ module.
Exclude_header_libs []string
// list of runtime libs that should not be installed along with the vendor
// variant of the C/C++ module.
Exclude_runtime_libs []string
// version script for this vendor variant
Version_script *string `android:"arch_variant"`
}
Recovery struct {
// list of shared libs that only should be used to build the recovery
// variant of the C/C++ module.
Shared_libs []string
// list of static libs that only should be used to build the recovery
// variant of the C/C++ module.
Static_libs []string
// list of shared libs that should not be used to build
// the recovery variant of the C/C++ module.
Exclude_shared_libs []string
// list of static libs that should not be used to build
// the recovery variant of the C/C++ module.
Exclude_static_libs []string
// list of header libs that should not be used to build the recovery variant
// of the C/C++ module.
Exclude_header_libs []string
}
Ramdisk struct {
// list of static libs that only should be used to build the recovery
// variant of the C/C++ module.
Static_libs []string
// list of shared libs that should not be used to build
// the ramdisk variant of the C/C++ module.
Exclude_shared_libs []string
// list of static libs that should not be used to build
// the ramdisk variant of the C/C++ module.
Exclude_static_libs []string
}
}
// make android::build:GetBuildNumber() available containing the build ID.
Use_version_lib *bool `android:"arch_variant"`
// Generate compact dynamic relocation table, default true.
Pack_relocations *bool `android:"arch_variant"`
// local file name to pass to the linker as --version_script
Version_script *string `android:"path,arch_variant"`
// list of static libs that should not be used to build this module
Exclude_static_libs []string
}
func NewBaseLinker(sanitize *sanitize) *baseLinker {
return &baseLinker{sanitize: sanitize}
}
// baseLinker provides support for shared_libs, static_libs, and whole_static_libs properties
type baseLinker struct {
Properties BaseLinkerProperties
dynamicProperties struct {
RunPaths []string `blueprint:"mutated"`
BuildStubs bool `blueprint:"mutated"`
}
sanitize *sanitize
}
func (linker *baseLinker) appendLdflags(flags []string) {
linker.Properties.Ldflags = append(linker.Properties.Ldflags, flags...)
}
func (linker *baseLinker) linkerInit(ctx BaseModuleContext) {
if ctx.toolchain().Is64Bit() {
linker.dynamicProperties.RunPaths = append(linker.dynamicProperties.RunPaths, "../lib64", "lib64")
} else {
linker.dynamicProperties.RunPaths = append(linker.dynamicProperties.RunPaths, "../lib", "lib")
}
}
func (linker *baseLinker) linkerProps() []interface{} {
return []interface{}{&linker.Properties, &linker.dynamicProperties}
}
func (linker *baseLinker) linkerDeps(ctx DepsContext, deps Deps) Deps {
deps.WholeStaticLibs = append(deps.WholeStaticLibs, linker.Properties.Whole_static_libs...)
deps.HeaderLibs = append(deps.HeaderLibs, linker.Properties.Header_libs...)
deps.StaticLibs = append(deps.StaticLibs, linker.Properties.Static_libs...)
deps.SharedLibs = append(deps.SharedLibs, linker.Properties.Shared_libs...)
deps.RuntimeLibs = append(deps.RuntimeLibs, linker.Properties.Runtime_libs...)
deps.ReexportHeaderLibHeaders = append(deps.ReexportHeaderLibHeaders, linker.Properties.Export_header_lib_headers...)
deps.ReexportStaticLibHeaders = append(deps.ReexportStaticLibHeaders, linker.Properties.Export_static_lib_headers...)
deps.ReexportSharedLibHeaders = append(deps.ReexportSharedLibHeaders, linker.Properties.Export_shared_lib_headers...)
deps.ReexportGeneratedHeaders = append(deps.ReexportGeneratedHeaders, linker.Properties.Export_generated_headers...)
deps.WholeStaticLibs = removeListFromList(deps.WholeStaticLibs, linker.Properties.Exclude_static_libs)
if Bool(linker.Properties.Use_version_lib) {
deps.WholeStaticLibs = append(deps.WholeStaticLibs, "libbuildversion")
}
if ctx.useVndk() {
deps.SharedLibs = append(deps.SharedLibs, linker.Properties.Target.Vendor.Shared_libs...)
deps.SharedLibs = removeListFromList(deps.SharedLibs, linker.Properties.Target.Vendor.Exclude_shared_libs)
deps.ReexportSharedLibHeaders = removeListFromList(deps.ReexportSharedLibHeaders, linker.Properties.Target.Vendor.Exclude_shared_libs)
deps.StaticLibs = removeListFromList(deps.StaticLibs, linker.Properties.Target.Vendor.Exclude_static_libs)
deps.HeaderLibs = removeListFromList(deps.HeaderLibs, linker.Properties.Target.Vendor.Exclude_header_libs)
deps.ReexportStaticLibHeaders = removeListFromList(deps.ReexportStaticLibHeaders, linker.Properties.Target.Vendor.Exclude_static_libs)
deps.WholeStaticLibs = removeListFromList(deps.WholeStaticLibs, linker.Properties.Target.Vendor.Exclude_static_libs)
deps.RuntimeLibs = removeListFromList(deps.RuntimeLibs, linker.Properties.Target.Vendor.Exclude_runtime_libs)
}
if ctx.inRecovery() {
deps.SharedLibs = append(deps.SharedLibs, linker.Properties.Target.Recovery.Shared_libs...)
deps.SharedLibs = removeListFromList(deps.SharedLibs, linker.Properties.Target.Recovery.Exclude_shared_libs)
deps.ReexportSharedLibHeaders = removeListFromList(deps.ReexportSharedLibHeaders, linker.Properties.Target.Recovery.Exclude_shared_libs)
deps.StaticLibs = append(deps.StaticLibs, linker.Properties.Target.Recovery.Static_libs...)
deps.StaticLibs = removeListFromList(deps.StaticLibs, linker.Properties.Target.Recovery.Exclude_static_libs)
deps.HeaderLibs = removeListFromList(deps.HeaderLibs, linker.Properties.Target.Recovery.Exclude_header_libs)
deps.ReexportHeaderLibHeaders = removeListFromList(deps.ReexportHeaderLibHeaders, linker.Properties.Target.Recovery.Exclude_header_libs)
deps.ReexportStaticLibHeaders = removeListFromList(deps.ReexportStaticLibHeaders, linker.Properties.Target.Recovery.Exclude_static_libs)
deps.WholeStaticLibs = removeListFromList(deps.WholeStaticLibs, linker.Properties.Target.Recovery.Exclude_static_libs)
}
if ctx.inRamdisk() {
deps.SharedLibs = removeListFromList(deps.SharedLibs, linker.Properties.Target.Recovery.Exclude_shared_libs)
deps.ReexportSharedLibHeaders = removeListFromList(deps.ReexportSharedLibHeaders, linker.Properties.Target.Recovery.Exclude_shared_libs)
deps.StaticLibs = append(deps.StaticLibs, linker.Properties.Target.Recovery.Static_libs...)
deps.StaticLibs = removeListFromList(deps.StaticLibs, linker.Properties.Target.Recovery.Exclude_static_libs)
deps.ReexportStaticLibHeaders = removeListFromList(deps.ReexportStaticLibHeaders, linker.Properties.Target.Recovery.Exclude_static_libs)
deps.WholeStaticLibs = removeListFromList(deps.WholeStaticLibs, linker.Properties.Target.Recovery.Exclude_static_libs)
}
if ctx.toolchain().Bionic() {
// libclang_rt.builtins and libatomic have to be last on the command line
if !Bool(linker.Properties.No_libcrt) {
deps.LateStaticLibs = append(deps.LateStaticLibs, config.BuiltinsRuntimeLibrary(ctx.toolchain()))
deps.LateStaticLibs = append(deps.LateStaticLibs, "libatomic")
}
systemSharedLibs := linker.Properties.System_shared_libs
if systemSharedLibs == nil {
// Provide a default system_shared_libs if it is unspecified. Note: If an
// empty list [] is specified, it implies that the module declines the
// default system_shared_libs.
systemSharedLibs = []string{"libc", "libm", "libdl"}
}
if inList("libdl", deps.SharedLibs) {
// If system_shared_libs has libc but not libdl, make sure shared_libs does not
// have libdl to avoid loading libdl before libc.
if inList("libc", systemSharedLibs) {
if !inList("libdl", systemSharedLibs) {
ctx.PropertyErrorf("shared_libs",
"libdl must be in system_shared_libs, not shared_libs")
}
_, deps.SharedLibs = removeFromList("libdl", deps.SharedLibs)
}
}
if inList("libc_scudo", deps.SharedLibs) {
// libc_scudo is an alternate implementation of all
// allocation functions (malloc, free), that uses
// the scudo allocator instead of the default native
// allocator. If this library is in the list, make
// sure it's first so it properly overrides the
// allocation functions of all other shared libraries.
_, deps.SharedLibs = removeFromList("libc_scudo", deps.SharedLibs)
deps.SharedLibs = append([]string{"libc_scudo"}, deps.SharedLibs...)
}
// If libc and libdl are both in system_shared_libs make sure libdl comes after libc
// to avoid loading libdl before libc.
if inList("libdl", systemSharedLibs) && inList("libc", systemSharedLibs) &&
indexList("libdl", systemSharedLibs) < indexList("libc", systemSharedLibs) {
ctx.PropertyErrorf("system_shared_libs", "libdl must be after libc")
}
deps.LateSharedLibs = append(deps.LateSharedLibs, systemSharedLibs...)
}
if ctx.Fuchsia() {
if ctx.ModuleName() != "libbioniccompat" &&
ctx.ModuleName() != "libcompiler_rt-extras" &&
ctx.ModuleName() != "libcompiler_rt" {
deps.StaticLibs = append(deps.StaticLibs, "libbioniccompat")
}
if ctx.ModuleName() != "libcompiler_rt" && ctx.ModuleName() != "libcompiler_rt-extras" {
deps.LateStaticLibs = append(deps.LateStaticLibs, "libcompiler_rt")
}
}
if ctx.Windows() {
deps.LateStaticLibs = append(deps.LateStaticLibs, "libwinpthread")
}
return deps
}
func (linker *baseLinker) useClangLld(ctx ModuleContext) bool {
// Clang lld is not ready for for Darwin host executables yet.
// See https://lld.llvm.org/AtomLLD.html for status of lld for Mach-O.
if ctx.Darwin() {
return false
}
if linker.Properties.Use_clang_lld != nil {
return Bool(linker.Properties.Use_clang_lld)
}
return true
}
// Check whether the SDK version is not older than the specific one
func CheckSdkVersionAtLeast(ctx ModuleContext, SdkVersion int) bool {
if ctx.sdkVersion() == "current" {
return true
}
parsedSdkVersion, err := strconv.Atoi(ctx.sdkVersion())
if err != nil {
ctx.PropertyErrorf("sdk_version",
"Invalid sdk_version value (must be int or current): %q",
ctx.sdkVersion())
}
if parsedSdkVersion < SdkVersion {
return false
}
return true
}
// ModuleContext extends BaseModuleContext
// BaseModuleContext should know if LLD is used?
func (linker *baseLinker) linkerFlags(ctx ModuleContext, flags Flags) Flags {
toolchain := ctx.toolchain()
hod := "Host"
if ctx.Os().Class == android.Device {
hod = "Device"
}
if linker.useClangLld(ctx) {
flags.Global.LdFlags = append(flags.Global.LdFlags, fmt.Sprintf("${config.%sGlobalLldflags}", hod))
if !BoolDefault(linker.Properties.Pack_relocations, true) {
flags.Global.LdFlags = append(flags.Global.LdFlags, "-Wl,--pack-dyn-relocs=none")
} else if ctx.Device() {
// The SHT_RELR relocations is only supported by API level >= 28.
// Do not turn this on if older version NDK is used.
if !ctx.useSdk() || CheckSdkVersionAtLeast(ctx, 28) {
flags.Global.LdFlags = append(flags.Global.LdFlags,
"-Wl,--pack-dyn-relocs=android+relr",
"-Wl,--use-android-relr-tags")
} else if CheckSdkVersionAtLeast(ctx, 23) {
flags.Global.LdFlags = append(flags.Global.LdFlags, "-Wl,--pack-dyn-relocs=android")
}
}
} else {
flags.Global.LdFlags = append(flags.Global.LdFlags, fmt.Sprintf("${config.%sGlobalLdflags}", hod))
}
if Bool(linker.Properties.Allow_undefined_symbols) {
if ctx.Darwin() {
// darwin defaults to treating undefined symbols as errors
flags.Global.LdFlags = append(flags.Global.LdFlags, "-Wl,-undefined,dynamic_lookup")
}
} else if !ctx.Darwin() && !ctx.Windows() {
flags.Global.LdFlags = append(flags.Global.LdFlags, "-Wl,--no-undefined")
}
if linker.useClangLld(ctx) {
flags.Global.LdFlags = append(flags.Global.LdFlags, toolchain.ClangLldflags())
} else {
flags.Global.LdFlags = append(flags.Global.LdFlags, toolchain.ClangLdflags())
}
if !ctx.toolchain().Bionic() && !ctx.Fuchsia() {
CheckBadHostLdlibs(ctx, "host_ldlibs", linker.Properties.Host_ldlibs)
flags.Local.LdFlags = append(flags.Local.LdFlags, linker.Properties.Host_ldlibs...)
if !ctx.Windows() {
// Add -ldl, -lpthread, -lm and -lrt to host builds to match the default behavior of device
// builds
flags.Global.LdFlags = append(flags.Global.LdFlags,
"-ldl",
"-lpthread",
"-lm",
)
if !ctx.Darwin() {
flags.Global.LdFlags = append(flags.Global.LdFlags, "-lrt")
}
}
}
if ctx.Fuchsia() {
flags.Global.LdFlags = append(flags.Global.LdFlags, "-lfdio", "-lzircon")
}
if ctx.toolchain().LibclangRuntimeLibraryArch() != "" {
flags.Global.LdFlags = append(flags.Global.LdFlags, "-Wl,--exclude-libs="+config.BuiltinsRuntimeLibrary(ctx.toolchain())+".a")
}
CheckBadLinkerFlags(ctx, "ldflags", linker.Properties.Ldflags)
flags.Local.LdFlags = append(flags.Local.LdFlags, proptools.NinjaAndShellEscapeList(linker.Properties.Ldflags)...)
if ctx.Host() && !ctx.Windows() {
rpath_prefix := `\$$ORIGIN/`
if ctx.Darwin() {
rpath_prefix = "@loader_path/"
}
if !ctx.static() {
for _, rpath := range linker.dynamicProperties.RunPaths {
flags.Global.LdFlags = append(flags.Global.LdFlags, "-Wl,-rpath,"+rpath_prefix+rpath)
}
}
}
if ctx.useSdk() && (ctx.Arch().ArchType != android.Mips && ctx.Arch().ArchType != android.Mips64) {
// The bionic linker now has support gnu style hashes (which are much faster!), but shipping
// to older devices requires the old style hash. Fortunately, we can build with both and
// it'll work anywhere.
// This is not currently supported on MIPS architectures.
flags.Global.LdFlags = append(flags.Global.LdFlags, "-Wl,--hash-style=both")
}
flags.Global.LdFlags = append(flags.Global.LdFlags, toolchain.ToolchainClangLdflags())
if Bool(linker.Properties.Group_static_libs) {
flags.GroupStaticLibs = true
}
// Version_script is not needed when linking stubs lib where the version
// script is created from the symbol map file.
if !linker.dynamicProperties.BuildStubs {
versionScript := ctx.ExpandOptionalSource(
linker.Properties.Version_script, "version_script")
if ctx.useVndk() && linker.Properties.Target.Vendor.Version_script != nil {
versionScript = ctx.ExpandOptionalSource(
linker.Properties.Target.Vendor.Version_script,
"target.vendor.version_script")
}
if versionScript.Valid() {
if ctx.Darwin() {
ctx.PropertyErrorf("version_script", "Not supported on Darwin")
} else {
flags.Local.LdFlags = append(flags.Local.LdFlags,
"-Wl,--version-script,"+versionScript.String())
flags.LdFlagsDeps = append(flags.LdFlagsDeps, versionScript.Path())
if linker.sanitize.isSanitizerEnabled(cfi) {
cfiExportsMap := android.PathForSource(ctx, cfiExportsMapPath)
flags.Local.LdFlags = append(flags.Local.LdFlags,
"-Wl,--version-script,"+cfiExportsMap.String())
flags.LdFlagsDeps = append(flags.LdFlagsDeps, cfiExportsMap)
}
}
}
}
return flags
}
func (linker *baseLinker) link(ctx ModuleContext,
flags Flags, deps PathDeps, objs Objects) android.Path {
panic(fmt.Errorf("baseLinker doesn't know how to link"))
}
// Injecting version symbols
// Some host modules want a version number, but we don't want to rebuild it every time. Optionally add a step
// after linking that injects a constant placeholder with the current version number.
func init() {
pctx.HostBinToolVariable("symbolInjectCmd", "symbol_inject")
}
var injectVersionSymbol = pctx.AndroidStaticRule("injectVersionSymbol",
blueprint.RuleParams{
Command: "$symbolInjectCmd -i $in -o $out -s soong_build_number " +
"-from 'SOONG BUILD NUMBER PLACEHOLDER' -v $buildNumberFromFile",
CommandDeps: []string{"$symbolInjectCmd"},
},
"buildNumberFromFile")
func (linker *baseLinker) injectVersionSymbol(ctx ModuleContext, in android.Path, out android.WritablePath) {
ctx.Build(pctx, android.BuildParams{
Rule: injectVersionSymbol,
Description: "inject version symbol",
Input: in,
Output: out,
Args: map[string]string{
"buildNumberFromFile": proptools.NinjaEscape(ctx.Config().BuildNumberFromFile()),
},
})
}
// Rule to generate .bss symbol ordering file.
var (
_ = pctx.SourcePathVariable("genSortedBssSymbolsPath", "build/soong/scripts/gen_sorted_bss_symbols.sh")
gen_sorted_bss_symbols = pctx.AndroidStaticRule("gen_sorted_bss_symbols",
blueprint.RuleParams{
Command: "CROSS_COMPILE=$crossCompile $genSortedBssSymbolsPath ${in} ${out}",
CommandDeps: []string{"$genSortedBssSymbolsPath", "${crossCompile}nm"},
},
"crossCompile")
)
func (linker *baseLinker) sortBssSymbolsBySize(ctx ModuleContext, in android.Path, symbolOrderingFile android.ModuleOutPath, flags builderFlags) string {
crossCompile := gccCmd(flags.toolchain, "")
ctx.Build(pctx, android.BuildParams{
Rule: gen_sorted_bss_symbols,
Description: "generate bss symbol order " + symbolOrderingFile.Base(),
Output: symbolOrderingFile,
Input: in,
Args: map[string]string{
"crossCompile": crossCompile,
},
})
return "-Wl,--symbol-ordering-file," + symbolOrderingFile.String()
}