a0a591a714
The only symbol that actually needs a prefix to avoid a collision is _start, and that can be handled with a copy of begin.S that uses a "#define" to rename _start to __dlwrap__start. Removing the prefixed symbols will also allow simplifying the host bionic build process by letting it directly reference the real _start. Test: build and run host bionic binary Change-Id: I50be786c16fe04b7f05c14ebfb74f710c7446ed9
558 lines
14 KiB
Text
558 lines
14 KiB
Text
// ========================================================
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// linker_wrapper - Linux Bionic (on the host)
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// ========================================================
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// This is used for bionic on (host) Linux to bootstrap our linker embedded into
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// a binary.
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//
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// Host bionic binaries do not have a PT_INTERP section, instead this gets
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// embedded as the entry point, and the linker is embedded as ELF sections in
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// each binary. There's a linker script that sets all of that up (generated by
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// extract_linker), and defines the extern symbols used in this file.
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package {
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default_applicable_licenses: ["bionic_linker_license"],
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}
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license {
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name: "bionic_linker_license",
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visibility: [":__subpackages__"],
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license_kinds: [
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"SPDX-license-identifier-BSD",
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],
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license_text: [
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"NOTICE",
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],
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}
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cc_object {
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name: "linker_wrapper",
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host_supported: true,
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device_supported: false,
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target: {
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linux_bionic: {
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enabled: true,
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},
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linux_glibc: {
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enabled: false,
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},
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darwin: {
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enabled: false,
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},
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},
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cflags: [
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"-fno-stack-protector",
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"-Wstrict-overflow=5",
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"-fvisibility=hidden",
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"-Wall",
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"-Wextra",
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"-Wno-unused",
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"-Werror",
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],
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srcs: [
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"linker_wrapper.cpp",
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],
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arch: {
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arm64: {
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srcs: ["arch/arm64/linker_wrapper_begin.S"],
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},
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x86_64: {
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srcs: ["arch/x86_64/linker_wrapper_begin.S"],
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},
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},
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header_libs: ["libc_headers"],
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// We need to access Bionic private headers in the linker.
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include_dirs: ["bionic/libc"],
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// b/182338959
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bazel_module: { bp2build_available: false },
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}
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// ========================================================
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// linker default configuration
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// ========================================================
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// Configuration for the linker binary and any of its static libraries.
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cc_defaults {
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name: "linker_defaults",
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arch: {
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arm: {
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cflags: ["-D__work_around_b_24465209__"],
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},
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x86: {
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cflags: ["-D__work_around_b_24465209__"],
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},
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},
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cflags: [
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"-fno-stack-protector",
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"-Wstrict-overflow=5",
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"-fvisibility=hidden",
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"-Wall",
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"-Wextra",
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"-Wunused",
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"-Werror",
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],
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// TODO: split out the asflags.
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asflags: [
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"-fno-stack-protector",
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"-Wstrict-overflow=5",
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"-fvisibility=hidden",
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"-Wall",
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"-Wextra",
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"-Wunused",
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"-Werror",
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],
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product_variables: {
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debuggable: {
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cppflags: ["-DUSE_LD_CONFIG_FILE"],
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},
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},
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cppflags: ["-Wold-style-cast"],
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static_libs: [
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"libziparchive",
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"libbase",
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"libz",
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"libasync_safe",
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"liblog",
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],
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// We need to access Bionic private headers in the linker.
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include_dirs: ["bionic/libc"],
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}
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// ========================================================
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// linker components
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// ========================================================
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// Enable a module on all targets the linker runs on (ordinary Android targets, Linux Bionic, and
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// native bridge implementations).
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cc_defaults {
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name: "linker_all_targets",
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defaults: ["linux_bionic_supported"],
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recovery_available: true,
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vendor_ramdisk_available: true,
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native_bridge_supported: true,
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}
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cc_library_static {
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name: "liblinker_main",
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defaults: ["linker_defaults", "linker_all_targets"],
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srcs: ["linker_main.cpp"],
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// Ensure that the compiler won't insert string function calls before ifuncs are resolved.
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cflags: ["-ffreestanding"],
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}
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cc_library_static {
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name: "liblinker_malloc",
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defaults: ["linker_defaults", "linker_all_targets"],
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srcs: ["linker_memory.cpp"],
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}
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cc_library_static {
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name: "liblinker_debuggerd_stub",
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defaults: ["linker_defaults", "linker_all_targets"],
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srcs: ["linker_debuggerd_stub.cpp"],
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}
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// ========================================================
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// template for the linker binary
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// ========================================================
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filegroup {
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name: "linker_sources",
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srcs: [
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"dlfcn.cpp",
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"linker.cpp",
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"linker_block_allocator.cpp",
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"linker_dlwarning.cpp",
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"linker_cfi.cpp",
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"linker_config.cpp",
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"linker_debug.cpp",
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"linker_gdb_support.cpp",
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"linker_globals.cpp",
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"linker_libc_support.c",
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"linker_libcxx_support.cpp",
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"linker_namespaces.cpp",
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"linker_logger.cpp",
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"linker_mapped_file_fragment.cpp",
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"linker_note_gnu_property.cpp",
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"linker_phdr.cpp",
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"linker_relocate.cpp",
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"linker_sdk_versions.cpp",
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"linker_soinfo.cpp",
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"linker_transparent_hugepage_support.cpp",
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"linker_tls.cpp",
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"linker_utils.cpp",
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"rt.cpp",
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],
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}
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filegroup {
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name: "linker_sources_arm",
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srcs: [
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"arch/arm/begin.S",
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"arch/arm_neon/linker_gnu_hash_neon.cpp",
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],
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}
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filegroup {
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name: "linker_sources_arm64",
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srcs: [
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"arch/arm64/begin.S",
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"arch/arm64/tlsdesc_resolver.S",
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"arch/arm_neon/linker_gnu_hash_neon.cpp",
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],
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}
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filegroup {
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name: "linker_sources_x86",
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srcs: [
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"arch/x86/begin.S",
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],
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}
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filegroup {
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name: "linker_sources_x86_64",
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srcs: [
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"arch/x86_64/begin.S",
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],
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}
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cc_defaults {
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name: "linker_version_script_overlay",
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arch: {
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arm: { version_script: "linker.arm.map" },
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arm64: { version_script: "linker.generic.map" },
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x86: { version_script: "linker.generic.map" },
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x86_64: { version_script: "linker.generic.map" },
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},
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}
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// A template for the linker binary. May be inherited by native bridge implementations.
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cc_defaults {
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name: "linker_bin_template",
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defaults: ["linker_defaults"],
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srcs: [":linker_sources"],
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arch: {
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arm: {
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srcs: [":linker_sources_arm"],
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},
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arm64: {
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srcs: [":linker_sources_arm64"],
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},
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x86: {
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srcs: [":linker_sources_x86"],
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},
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x86_64: {
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srcs: [":linker_sources_x86_64"],
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},
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},
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// -shared is used to overwrite the -Bstatic and -static flags triggered by enabling
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// static_executable. This dynamic linker is actually a shared object linked with static
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// libraries.
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ldflags: [
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"-shared",
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"-Wl,-Bsymbolic",
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"-Wl,--exclude-libs,ALL",
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"-Wl,-soname,ld-android.so",
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],
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// we are going to link libc++_static manually because
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// when stl is not set to "none" build system adds libdl
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// to the list of static libraries which needs to be
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// avoided in the case of building loader.
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stl: "none",
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// we don't want crtbegin.o (because we have begin.o), so unset it
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// just for this module
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nocrt: true,
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static_executable: true,
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// Leave the symbols in the shared library so that stack unwinders can produce
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// meaningful name resolution.
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strip: {
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keep_symbols: true,
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},
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// Insert an extra objcopy step to add prefix to symbols. This is needed to prevent gdb
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// looking up symbols in the linker by mistake.
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prefix_symbols: "__dl_",
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sanitize: {
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hwaddress: false,
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},
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static_libs: [
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"liblinker_main",
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"liblinker_malloc",
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"libc++_static",
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"libc_nomalloc",
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"libc_dynamic_dispatch",
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"libm",
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"libunwind",
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],
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// Ensure that if the linker needs __gnu_Unwind_Find_exidx, then the linker will have a
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// definition of the symbol. The linker links against libgcc.a, whose arm32 unwinder has a weak
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// reference to __gnu_Unwind_Find_exidx, which isn't sufficient to pull in the strong definition
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// of __gnu_Unwind_Find_exidx from libc. An unresolved weak reference would create a
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// non-relative dynamic relocation in the linker binary, which complicates linker startup.
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//
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// This line should be unnecessary because the linker's dependency on libunwind_llvm.a should
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// override libgcc.a, but this line provides a simpler guarantee. It can be removed once the
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// linker stops linking against libgcc.a's arm32 unwinder.
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whole_static_libs: ["libc_unwind_static"],
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system_shared_libs: [],
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// Opt out of native_coverage when opting out of system_shared_libs
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native_coverage: false,
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}
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// ========================================================
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// linker[_asan][64] binary
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// ========================================================
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cc_binary {
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name: "linker",
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defaults: [
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"linker_bin_template",
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"linux_bionic_supported",
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"linker_version_script_overlay",
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],
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srcs: [
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"linker_translate_path.cpp",
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],
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symlinks: ["linker_asan"],
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multilib: {
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lib64: {
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suffix: "64",
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},
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},
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compile_multilib: "both",
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recovery_available: true,
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vendor_ramdisk_available: true,
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apex_available: [
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"//apex_available:platform",
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"com.android.runtime",
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],
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target: {
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android: {
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srcs: [
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"linker_debuggerd_android.cpp",
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],
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static_libs: [
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"libc++demangle",
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"libdebuggerd_handler_fallback",
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],
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},
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linux_bionic: {
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static_libs: [
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"liblinker_debuggerd_stub",
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],
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},
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android_arm64: {
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pgo: {
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profile_file: "bionic/linker_arm_arm64.profdata",
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},
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},
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android_arm: {
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pgo: {
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profile_file: "bionic/linker_arm_arm64.profdata",
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},
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},
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android_x86_64: {
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pgo: {
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profile_file: "bionic/linker_x86_x86_64.profdata",
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},
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},
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android_x86: {
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pgo: {
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profile_file: "bionic/linker_x86_x86_64.profdata",
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},
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},
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},
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lto: {
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never: true,
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},
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pgo: {
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sampling: true,
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},
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}
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// ========================================================
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// assorted modules
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// ========================================================
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sh_binary {
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name: "ldd",
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src: "ldd.sh",
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bazel_module: { bp2build_available: true },
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}
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// Used to generate binaries that can be backed by transparent hugepages.
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cc_defaults {
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name: "linker_hugepage_aligned",
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arch: {
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arm64: {
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ldflags: ["-z max-page-size=0x200000"],
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},
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x86_64: {
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ldflags: ["-z max-page-size=0x200000"],
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},
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},
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}
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cc_library {
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// NOTE: --exclude-libs=libgcc.a makes sure that any symbols ld-android.so pulls from
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// libgcc.a are made static to ld-android.so. This in turn ensures that libraries that
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// a) pull symbols from libgcc.a and b) depend on ld-android.so will not rely on ld-android.so
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// to provide those symbols, but will instead pull them from libgcc.a. Specifically,
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// we use this property to make sure libc.so has its own copy of the code from
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// libgcc.a it uses.
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//
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// DO NOT REMOVE --exclude-libs!
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ldflags: [
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"-Wl,--exclude-libs=libgcc.a",
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"-Wl,--exclude-libs=libgcc_stripped.a",
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"-Wl,--exclude-libs=libclang_rt.builtins-arm-android.a",
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"-Wl,--exclude-libs=libclang_rt.builtins-aarch64-android.a",
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"-Wl,--exclude-libs=libclang_rt.builtins-i686-android.a",
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"-Wl,--exclude-libs=libclang_rt.builtins-x86_64-android.a",
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],
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|
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// for x86, exclude libgcc_eh.a for the same reasons as above
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arch: {
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x86: {
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ldflags: ["-Wl,--exclude-libs=libgcc_eh.a"],
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},
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x86_64: {
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ldflags: ["-Wl,--exclude-libs=libgcc_eh.a"],
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},
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},
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srcs: ["ld_android.cpp"],
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cflags: [
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"-Wall",
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"-Wextra",
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"-Wunused",
|
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"-Werror",
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],
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stl: "none",
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|
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name: "ld-android",
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defaults: ["linux_bionic_supported", "linker_version_script_overlay"],
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ramdisk_available: true,
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|
vendor_ramdisk_available: true,
|
|
recovery_available: true,
|
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native_bridge_supported: true,
|
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|
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nocrt: true,
|
|
system_shared_libs: [],
|
|
header_libs: ["libc_headers"],
|
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|
|
// Opt out of native_coverage when opting out of system_shared_libs
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native_coverage: false,
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|
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sanitize: {
|
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never: true,
|
|
},
|
|
|
|
apex_available: [
|
|
"//apex_available:platform",
|
|
"com.android.runtime",
|
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],
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|
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lto: {
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never: true,
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},
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}
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|
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cc_test {
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name: "linker-unit-tests",
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|
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cflags: [
|
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"-g",
|
|
"-Wall",
|
|
"-Wextra",
|
|
"-Wunused",
|
|
"-Werror",
|
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],
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|
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// We need to access Bionic private headers in the linker.
|
|
include_dirs: ["bionic/libc"],
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|
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srcs: [
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// Tests.
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"linker_block_allocator_test.cpp",
|
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"linker_config_test.cpp",
|
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"linked_list_test.cpp",
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"linker_note_gnu_property_test.cpp",
|
|
"linker_sleb128_test.cpp",
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"linker_utils_test.cpp",
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"linker_gnu_hash_test.cpp",
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|
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// Parts of the linker that we're testing.
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"linker_block_allocator.cpp",
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"linker_config.cpp",
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"linker_debug.cpp",
|
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"linker_note_gnu_property.cpp",
|
|
"linker_test_globals.cpp",
|
|
"linker_utils.cpp",
|
|
],
|
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|
|
static_libs: [
|
|
"libasync_safe",
|
|
"libbase",
|
|
"liblog",
|
|
],
|
|
|
|
arch: {
|
|
arm: {
|
|
srcs: ["arch/arm_neon/linker_gnu_hash_neon.cpp"],
|
|
},
|
|
arm64: {
|
|
srcs: ["arch/arm_neon/linker_gnu_hash_neon.cpp"],
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|
},
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},
|
|
}
|
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cc_benchmark {
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|
name: "linker-benchmarks",
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|
|
srcs: [
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"linker_gnu_hash_benchmark.cpp",
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|
],
|
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|
|
arch: {
|
|
arm: {
|
|
srcs: ["arch/arm_neon/linker_gnu_hash_neon.cpp"],
|
|
},
|
|
arm64: {
|
|
srcs: ["arch/arm_neon/linker_gnu_hash_neon.cpp"],
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|
},
|
|
},
|
|
}
|