platform_build_soong/cc/linker.go

269 lines
9.8 KiB
Go

// 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"
"fmt"
"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
// 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 libgcc.a
No_libgcc *bool
// -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"`
Target struct {
Vendor struct {
// list of shared libs that should not be used to build
// the vendor variant of the C/C++ module.
Exclude_shared_libs []string
}
}
}
func NewBaseLinker() *baseLinker {
return &baseLinker{}
}
// baseLinker provides support for shared_libs, static_libs, and whole_static_libs properties
type baseLinker struct {
Properties BaseLinkerProperties
dynamicProperties struct {
RunPaths []string `blueprint:"mutated"`
}
}
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 BaseModuleContext, 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.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...)
if ctx.vndk() {
deps.SharedLibs = removeListFromList(deps.SharedLibs, linker.Properties.Target.Vendor.Exclude_shared_libs)
deps.ReexportSharedLibHeaders = removeListFromList(deps.ReexportSharedLibHeaders, linker.Properties.Target.Vendor.Exclude_shared_libs)
}
if ctx.ModuleName() != "libcompiler_rt-extras" {
deps.LateStaticLibs = append(deps.LateStaticLibs, "libcompiler_rt-extras")
}
if ctx.toolchain().Bionic() {
// libgcc and libatomic have to be last on the command line
deps.LateStaticLibs = append(deps.LateStaticLibs, "libatomic")
if !Bool(linker.Properties.No_libgcc) {
deps.LateStaticLibs = append(deps.LateStaticLibs, "libgcc")
}
if !ctx.static() {
systemSharedLibs := linker.Properties.System_shared_libs
if systemSharedLibs == nil {
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 libc and libdl are both in system_shared_libs make sure libd 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...)
} else if ctx.sdk() || ctx.vndk() {
deps.LateSharedLibs = append(deps.LateSharedLibs, "libc", "libm", "libdl")
}
}
if ctx.Windows() {
deps.LateStaticLibs = append(deps.LateStaticLibs, "libwinpthread")
}
return deps
}
func (linker *baseLinker) linkerFlags(ctx ModuleContext, flags Flags) Flags {
toolchain := ctx.toolchain()
if !ctx.noDefaultCompilerFlags() {
if Bool(linker.Properties.Allow_undefined_symbols) {
if ctx.Darwin() {
// darwin defaults to treating undefined symbols as errors
flags.LdFlags = append(flags.LdFlags, "-Wl,-undefined,dynamic_lookup")
}
} else if !ctx.Darwin() {
flags.LdFlags = append(flags.LdFlags, "-Wl,--no-undefined")
}
if flags.Clang {
flags.LdFlags = append(flags.LdFlags, toolchain.ClangLdflags())
} else {
flags.LdFlags = append(flags.LdFlags, toolchain.Ldflags())
}
if !ctx.toolchain().Bionic() {
CheckBadHostLdlibs(ctx, "host_ldlibs", linker.Properties.Host_ldlibs)
flags.LdFlags = append(flags.LdFlags, linker.Properties.Host_ldlibs...)
if !ctx.Windows() {
// Add -ldl, -lpthread and -lrt to host builds to match the default behavior of device
// builds
flags.LdFlags = append(flags.LdFlags,
"-ldl",
"-lpthread",
)
if !ctx.Darwin() {
flags.LdFlags = append(flags.LdFlags, "-lrt")
}
}
}
}
CheckBadLinkerFlags(ctx, "ldflags", linker.Properties.Ldflags)
flags.LdFlags = append(flags.LdFlags, proptools.NinjaAndShellEscape(linker.Properties.Ldflags)...)
if ctx.Host() {
rpath_prefix := `\$$ORIGIN/`
if ctx.Darwin() {
rpath_prefix = "@loader_path/"
}
if !ctx.static() {
for _, rpath := range linker.dynamicProperties.RunPaths {
flags.LdFlags = append(flags.LdFlags, "-Wl,-rpath,"+rpath_prefix+rpath)
}
}
}
if ctx.sdk() && (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.LdFlags = append(flags.LdFlags, "-Wl,--hash-style=both")
}
if flags.Clang {
flags.LdFlags = append(flags.LdFlags, toolchain.ToolchainClangLdflags())
} else {
flags.LdFlags = append(flags.LdFlags, toolchain.ToolchainLdflags())
}
if Bool(linker.Properties.Group_static_libs) {
flags.GroupStaticLibs = true
}
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"))
}