Files
build_soong/cc/config/x86_linux_host.go
Kalesh Singh f4ffe0a026 soong: Add crt_pad_segment to .so's
crt_pad_segment adds a NOTE to the ELF which is used by the binoic
loader to determine whether it should pad segments when mapping them
into the virtual address space, such that there are no gaps between
mappings of consecutive segments. This avoids an increase in
unreclaimable kernel slab memory usage for VMAs on devices where the
runtime-page-size > elf-segment-p_align.

Since -fandroid-pad-segment [1] respects -nostdlib used in android
platform builds, soong must link in crt_pad_segment to platform shared
libraries.

For simplicity, link crt_pad_segment everywhere that crtend_so is
applicable, ignoring nocrt property, as there is no other reason
to track these separately.

Example:

❯ readelf -WS /system/lib64/libc++.so [Output simplified]

...
Section Headers:
  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
...
  [ 2] .note.android.pad_segment NOTE            0000000000000288 000288 000018 00   A  0   0  4
...

[1] https://github.com/llvm/llvm-project/pull/77244

Bug: 316403210
Test: readelf -WS <lib>.so
Change-Id: Icc06611376cfd5ee4de7281b4134f9f8ffe7ca60
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
2024-01-31 19:42:31 -08:00

412 lines
11 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 config
import (
"strings"
"android/soong/android"
)
var (
linuxCflags = []string{
"-Wa,--noexecstack",
"-fPIC",
"-U_FORTIFY_SOURCE",
"-D_FORTIFY_SOURCE=2",
"-fstack-protector",
// Workaround differences in inttypes.h between host and target.
//See bug 12708004.
"-D__STDC_FORMAT_MACROS",
"-D__STDC_CONSTANT_MACROS",
"--gcc-toolchain=${LinuxGccRoot}",
"-fstack-protector-strong",
}
linuxGlibcCflags = []string{
"--sysroot ${LinuxGccRoot}/sysroot",
}
linuxMuslCflags = []string{
"-D_LIBCPP_HAS_MUSL_LIBC",
"-DANDROID_HOST_MUSL",
"-nostdlibinc",
"--sysroot /dev/null",
}
linuxLdflags = []string{
"-Wl,-z,noexecstack",
"-Wl,-z,relro",
"-Wl,-z,now",
"-Wl,--no-undefined-version",
"--gcc-toolchain=${LinuxGccRoot}",
}
linuxLldflags = append(linuxLdflags,
"-Wl,--compress-debug-sections=zstd",
)
linuxGlibcLdflags = []string{
"--sysroot ${LinuxGccRoot}/sysroot",
}
linuxMuslLdflags = []string{
"-nostdlib",
"--sysroot /dev/null",
}
// Extended cflags
linuxX86Cflags = []string{
"-msse3",
"-m32",
"-march=prescott",
"-D_FILE_OFFSET_BITS=64",
"-D_LARGEFILE_SOURCE=1",
}
linuxX8664Cflags = []string{
"-m64",
}
linuxX86Ldflags = []string{
"-m32",
"-B${LinuxGccRoot}/lib/gcc/${LinuxGccTriple}/${LinuxGccVersion}/32",
"-L${LinuxGccRoot}/lib/gcc/${LinuxGccTriple}/${LinuxGccVersion}/32",
"-L${LinuxGccRoot}/${LinuxGccTriple}/lib32",
}
linuxX8664Ldflags = []string{
"-m64",
"-B${LinuxGccRoot}/lib/gcc/${LinuxGccTriple}/${LinuxGccVersion}",
"-L${LinuxGccRoot}/lib/gcc/${LinuxGccTriple}/${LinuxGccVersion}",
"-L${LinuxGccRoot}/${LinuxGccTriple}/lib64",
}
linuxAvailableLibraries = addPrefix([]string{
"c",
"dl",
"gcc",
"gcc_s",
"m",
"ncurses",
"pthread",
"resolv",
"rt",
"util",
}, "-l")
muslCrtBeginStaticBinary, muslCrtEndStaticBinary = []string{"libc_musl_crtbegin_static"}, []string{"libc_musl_crtend"}
muslCrtBeginSharedBinary, muslCrtEndSharedBinary = []string{"libc_musl_crtbegin_dynamic"}, []string{"libc_musl_crtend"}
muslCrtBeginSharedLibrary, muslCrtEndSharedLibrary = []string{"libc_musl_crtbegin_so"}, []string{"libc_musl_crtend_so"}
MuslDefaultSharedLibraries = []string{"libc_musl"}
)
const (
linuxGccVersion = "4.8.3"
linuxGlibcVersion = "2.17"
)
func init() {
exportedVars.ExportStringStaticVariable("LinuxGccVersion", linuxGccVersion)
exportedVars.ExportStringStaticVariable("LinuxGlibcVersion", linuxGlibcVersion)
// Most places use the full GCC version. A few only use up to the first two numbers.
if p := strings.Split(linuxGccVersion, "."); len(p) > 2 {
exportedVars.ExportStringStaticVariable("ShortLinuxGccVersion", strings.Join(p[:2], "."))
} else {
exportedVars.ExportStringStaticVariable("ShortLinuxGccVersion", linuxGccVersion)
}
exportedVars.ExportSourcePathVariable("LinuxGccRoot",
"prebuilts/gcc/linux-x86/host/x86_64-linux-glibc${LinuxGlibcVersion}-${ShortLinuxGccVersion}")
exportedVars.ExportStringListStaticVariable("LinuxGccTriple", []string{"x86_64-linux"})
exportedVars.ExportStringListStaticVariable("LinuxCflags", linuxCflags)
exportedVars.ExportStringListStaticVariable("LinuxLdflags", linuxLdflags)
exportedVars.ExportStringListStaticVariable("LinuxLldflags", linuxLldflags)
exportedVars.ExportStringListStaticVariable("LinuxGlibcCflags", linuxGlibcCflags)
exportedVars.ExportStringListStaticVariable("LinuxGlibcLdflags", linuxGlibcLdflags)
exportedVars.ExportStringListStaticVariable("LinuxGlibcLldflags", linuxGlibcLdflags)
exportedVars.ExportStringListStaticVariable("LinuxMuslCflags", linuxMuslCflags)
exportedVars.ExportStringListStaticVariable("LinuxMuslLdflags", linuxMuslLdflags)
exportedVars.ExportStringListStaticVariable("LinuxMuslLldflags", linuxMuslLdflags)
exportedVars.ExportStringListStaticVariable("LinuxX86Cflags", linuxX86Cflags)
exportedVars.ExportStringListStaticVariable("LinuxX8664Cflags", linuxX8664Cflags)
exportedVars.ExportStringListStaticVariable("LinuxX86Ldflags", linuxX86Ldflags)
exportedVars.ExportStringListStaticVariable("LinuxX86Lldflags", linuxX86Ldflags)
exportedVars.ExportStringListStaticVariable("LinuxX8664Ldflags", linuxX8664Ldflags)
exportedVars.ExportStringListStaticVariable("LinuxX8664Lldflags", linuxX8664Ldflags)
// Yasm flags
exportedVars.ExportStringListStaticVariable("LinuxX86YasmFlags", []string{"-f elf32 -m x86"})
exportedVars.ExportStringListStaticVariable("LinuxX8664YasmFlags", []string{"-f elf64 -m amd64"})
}
type toolchainLinux struct {
toolchainBase
cFlags, ldFlags string
}
type toolchainLinuxX86 struct {
toolchain32Bit
toolchainLinux
}
type toolchainLinuxX8664 struct {
toolchain64Bit
toolchainLinux
}
func (t *toolchainLinuxX86) Name() string {
return "x86"
}
func (t *toolchainLinuxX8664) Name() string {
return "x86_64"
}
func (t *toolchainLinux) IncludeFlags() string {
return ""
}
func (t *toolchainLinuxX86) Cflags() string {
return "${config.LinuxCflags} ${config.LinuxX86Cflags}"
}
func (t *toolchainLinuxX86) Cppflags() string {
return ""
}
func (t *toolchainLinuxX8664) Cflags() string {
return "${config.LinuxCflags} ${config.LinuxX8664Cflags}"
}
func (t *toolchainLinuxX8664) Cppflags() string {
return ""
}
func (t *toolchainLinuxX86) Ldflags() string {
return "${config.LinuxLdflags} ${config.LinuxX86Ldflags}"
}
func (t *toolchainLinuxX86) Lldflags() string {
return "${config.LinuxLldflags} ${config.LinuxX86Lldflags}"
}
func (t *toolchainLinuxX8664) Ldflags() string {
return "${config.LinuxLdflags} ${config.LinuxX8664Ldflags}"
}
func (t *toolchainLinuxX8664) Lldflags() string {
return "${config.LinuxLldflags} ${config.LinuxX8664Lldflags}"
}
func (t *toolchainLinuxX86) YasmFlags() string {
return "${config.LinuxX86YasmFlags}"
}
func (t *toolchainLinuxX8664) YasmFlags() string {
return "${config.LinuxX8664YasmFlags}"
}
func (toolchainLinuxX86) LibclangRuntimeLibraryArch() string {
return "i386"
}
func (toolchainLinuxX8664) LibclangRuntimeLibraryArch() string {
return "x86_64"
}
func (t *toolchainLinux) AvailableLibraries() []string {
return linuxAvailableLibraries
}
func (toolchainLinux) ShlibSuffix() string {
return ".so"
}
func (toolchainLinux) ExecutableSuffix() string {
return ""
}
// glibc specialization of the linux toolchain
type toolchainGlibc struct {
toolchainNoCrt
}
func (toolchainGlibc) Glibc() bool { return true }
func (toolchainGlibc) Cflags() string {
return "${config.LinuxGlibcCflags}"
}
func (toolchainGlibc) Ldflags() string {
return "${config.LinuxGlibcLdflags}"
}
func (toolchainGlibc) Lldflags() string {
return "${config.LinuxGlibcLldflags}"
}
type toolchainLinuxGlibcX86 struct {
toolchainLinuxX86
toolchainGlibc
}
type toolchainLinuxGlibcX8664 struct {
toolchainLinuxX8664
toolchainGlibc
}
func (t *toolchainLinuxGlibcX86) ClangTriple() string {
return "i686-linux-gnu"
}
func (t *toolchainLinuxGlibcX86) Cflags() string {
return t.toolchainLinuxX86.Cflags() + " " + t.toolchainGlibc.Cflags()
}
func (t *toolchainLinuxGlibcX86) Ldflags() string {
return t.toolchainLinuxX86.Ldflags() + " " + t.toolchainGlibc.Ldflags()
}
func (t *toolchainLinuxGlibcX86) Lldflags() string {
return t.toolchainLinuxX86.Lldflags() + " " + t.toolchainGlibc.Lldflags()
}
func (t *toolchainLinuxGlibcX8664) ClangTriple() string {
return "x86_64-linux-gnu"
}
func (t *toolchainLinuxGlibcX8664) Cflags() string {
return t.toolchainLinuxX8664.Cflags() + " " + t.toolchainGlibc.Cflags()
}
func (t *toolchainLinuxGlibcX8664) Ldflags() string {
return t.toolchainLinuxX8664.Ldflags() + " " + t.toolchainGlibc.Ldflags()
}
func (t *toolchainLinuxGlibcX8664) Lldflags() string {
return t.toolchainLinuxX8664.Lldflags() + " " + t.toolchainGlibc.Lldflags()
}
var toolchainLinuxGlibcX86Singleton Toolchain = &toolchainLinuxGlibcX86{}
var toolchainLinuxGlibcX8664Singleton Toolchain = &toolchainLinuxGlibcX8664{}
func linuxGlibcX86ToolchainFactory(arch android.Arch) Toolchain {
return toolchainLinuxGlibcX86Singleton
}
func linuxGlibcX8664ToolchainFactory(arch android.Arch) Toolchain {
return toolchainLinuxGlibcX8664Singleton
}
// musl specialization of the linux toolchain
type toolchainMusl struct {
}
func (toolchainMusl) Musl() bool { return true }
func (toolchainMusl) CrtBeginStaticBinary() []string { return muslCrtBeginStaticBinary }
func (toolchainMusl) CrtBeginSharedBinary() []string { return muslCrtBeginSharedBinary }
func (toolchainMusl) CrtBeginSharedLibrary() []string { return muslCrtBeginSharedLibrary }
func (toolchainMusl) CrtEndStaticBinary() []string { return muslCrtEndStaticBinary }
func (toolchainMusl) CrtEndSharedBinary() []string { return muslCrtEndSharedBinary }
func (toolchainMusl) CrtEndSharedLibrary() []string { return muslCrtEndSharedLibrary }
func (toolchainMusl) CrtPadSegmentSharedLibrary() []string { return nil }
func (toolchainMusl) DefaultSharedLibraries() []string { return MuslDefaultSharedLibraries }
func (toolchainMusl) Cflags() string {
return "${config.LinuxMuslCflags}"
}
func (toolchainMusl) Ldflags() string {
return "${config.LinuxMuslLdflags}"
}
func (toolchainMusl) Lldflags() string {
return "${config.LinuxMuslLldflags}"
}
type toolchainLinuxMuslX86 struct {
toolchainLinuxX86
toolchainMusl
}
type toolchainLinuxMuslX8664 struct {
toolchainLinuxX8664
toolchainMusl
}
func (t *toolchainLinuxMuslX86) ClangTriple() string {
return "i686-linux-musl"
}
func (t *toolchainLinuxMuslX86) Cflags() string {
return t.toolchainLinuxX86.Cflags() + " " + t.toolchainMusl.Cflags()
}
func (t *toolchainLinuxMuslX86) Ldflags() string {
return t.toolchainLinuxX86.Ldflags() + " " + t.toolchainMusl.Ldflags()
}
func (t *toolchainLinuxMuslX86) Lldflags() string {
return t.toolchainLinuxX86.Lldflags() + " " + t.toolchainMusl.Lldflags()
}
func (t *toolchainLinuxMuslX8664) ClangTriple() string {
return "x86_64-linux-musl"
}
func (t *toolchainLinuxMuslX8664) Cflags() string {
return t.toolchainLinuxX8664.Cflags() + " " + t.toolchainMusl.Cflags()
}
func (t *toolchainLinuxMuslX8664) Ldflags() string {
return t.toolchainLinuxX8664.Ldflags() + " " + t.toolchainMusl.Ldflags()
}
func (t *toolchainLinuxMuslX8664) Lldflags() string {
return t.toolchainLinuxX8664.Lldflags() + " " + t.toolchainMusl.Lldflags()
}
var toolchainLinuxMuslX86Singleton Toolchain = &toolchainLinuxMuslX86{}
var toolchainLinuxMuslX8664Singleton Toolchain = &toolchainLinuxMuslX8664{}
func linuxMuslX86ToolchainFactory(arch android.Arch) Toolchain {
return toolchainLinuxMuslX86Singleton
}
func linuxMuslX8664ToolchainFactory(arch android.Arch) Toolchain {
return toolchainLinuxMuslX8664Singleton
}
func init() {
registerToolchainFactory(android.Linux, android.X86, linuxGlibcX86ToolchainFactory)
registerToolchainFactory(android.Linux, android.X86_64, linuxGlibcX8664ToolchainFactory)
registerToolchainFactory(android.LinuxMusl, android.X86, linuxMuslX86ToolchainFactory)
registerToolchainFactory(android.LinuxMusl, android.X86_64, linuxMuslX8664ToolchainFactory)
}