From 6c72e46bff8a33df3ab2122e12388ef828ca3b07 Mon Sep 17 00:00:00 2001
From: Roland McGrath <mcgrathr@google.com>
Date: Sat, 27 Apr 2019 00:31:42 +0000
Subject: [PATCH] [build][ldso] Use libprefix for all instrumented variants
Also add an explicit option in environment() to enable a per-variant
libprefix in all variants of a toolchain (or none). By default, each
variant that has the "instrumented" tag gets "$variant/" appended to its
${toolchain.libprefix} value. Remove the "asan" variant's explicit
toolchain_vars.libprefix setting, which is now redundant.
The dynamic linker is compiled to request the libprefix from the loader
service, and all executables have the prefixed name in PT_INTERP so they
get the same variant's dynamic linker.
Bug: BLD-429 #done
Bug: ZX-3624 #done
Change-Id: Ia74bc8d449aa6ce3ded00df8940b057e790486f4
---
zircon/public/gn/config/BUILD.gn | 16 +++--
zircon/public/gn/config/standard.gni | 3 -
zircon/public/gn/toolchain/environment.gni | 69 +++++++++++++--------
zircon/third_party/ulib/musl/ldso/BUILD.gn | 7 +++
zircon/third_party/ulib/musl/ldso/dynlink.c | 5 ++
5 files changed, 67 insertions(+), 33 deletions(-)
diff --git a/zircon/public/gn/config/BUILD.gn b/zircon/public/gn/config/BUILD.gn
index f7ccccbb3a8..23665bc2dac 100644
--- a/zircon/public/gn/config/BUILD.gn
+++ b/zircon/public/gn/config/BUILD.gn
@@ -520,11 +520,17 @@ config("user_executable") {
compiler_flags = [ "-fPIE" ]
asmflags = compiler_flags
cflags = compiler_flags
- ldflags = compiler_flags
- ldflags += [
- "-Wl,-pie",
- "-Wl,-dynamic-linker,ld.so.1",
- ]
+ ldflags = compiler_flags + [ "-Wl,-pie" ]
+ } else {
+ ldflags = []
+ }
+
+ # Specify the dynamic linker if building a variant that uses a separate
+ # set of libraries. With GCC, the dynamic linker must be explicit even
+ # in the default case because the compiler driver is not inherently
+ # configured for Fuchsia as it is in Clang.
+ if (is_gcc || toolchain.libprefix != "") {
+ ldflags += [ "-Wl,-dynamic-linker,${toolchain.libprefix}ld.so.1" ]
}
}
diff --git a/zircon/public/gn/config/standard.gni b/zircon/public/gn/config/standard.gni
index dd303222d56..9ea36bf1f7b 100644
--- a/zircon/public/gn/config/standard.gni
+++ b/zircon/public/gn/config/standard.gni
@@ -233,9 +233,6 @@ standard_variants = [
add = [ "$zx/system/core/devmgr:driver_deps.$name" ]
},
]
- toolchain_vars = {
- libprefix = "asan/"
- }
tags = [
"instrumented",
"useronly",
diff --git a/zircon/public/gn/toolchain/environment.gni b/zircon/public/gn/toolchain/environment.gni
index 6acbdf2dfb6..13ee1b9ba23 100644
--- a/zircon/public/gn/toolchain/environment.gni
+++ b/zircon/public/gn/toolchain/environment.gni
@@ -38,19 +38,21 @@ declare_args() {
# Selector scope parameters
#
# * variant
- # - Required: The variant to use when this selector matches. If this is a
- # string then it must match a fully-defined variant elsewhere in the
- # list (or in $default_variants + $standard_variants, which is appended
- # implicitly to the $variants list). If it's a scope then it defines a
- # new variant (see details below).
+ # - Required: The variant to use when this selector matches. If this
+ # is a string then it must match a fully-defined variant elsewhere in
+ # the list (or in $default_variants + $standard_variants, which is
+ # appended implicitly to the $variants list). If it's a scope then
+ # it defines a new variant (see details below).
# - Type: string or scope, described below
#
# * cpu
- # - Optional: If nonempty, match only when $current_cpu is one in the list.
+ # - Optional: If nonempty, match only when $current_cpu is one in the
+ # - list.
# - Type: list(string)
#
# * os
- # - Optional: If nonempty, match only when $current_os is one in the list.
+ # - Optional: If nonempty, match only when $current_os is one in the
+ # - list.
# - Type: list(string)
#
# * host
@@ -82,8 +84,9 @@ declare_args() {
# - Type: list(string)
#
# * target_type
- # - Optional: If nonempty, a list of target types to match. This is one of
- # "executable", "host_tool", "loadable_module", "driver", or "test".
+ # - Optional: If nonempty, a list of target types to match. This is
+ # one of "executable", "host_tool", "loadable_module", "driver", or
+ # "test".
# Note, test_driver() matches as "driver".
# - Type: list(string)
#
@@ -106,9 +109,10 @@ declare_args() {
# - Type: list(label_no_toolchain)
#
# * output_name
- # - Optional: If nonempty, match only when the `output_name` of the target
- # is one in the list. Note `output_name` defaults to `target_name`,
- # and does not include prefixes or suffixes like ".so" or ".exe".
+ # - Optional: If nonempty, match only when the `output_name` of the
+ # target is one in the list. Note `output_name` defaults to
+ # `target_name`, and does not include prefixes or suffixes like ".so"
+ # or ".exe".
# - Type: list(string)
#
# An element with a scope for `.variant` defines a new variant. Each
@@ -297,14 +301,23 @@ declare_args() {
# This is just like $toolchain_args passed to toolchain() in bare GN.
#
# * toolchain_vars
-# - Optional: A scope imported into the $toolchain scope in these toolchains.
-# This can store useful toolchain-specific variables that should be
-# available within the toolchain. $toolchain automatically contains
-# `tool_dir`, `tool_prefix`, `cc, and `cxx`, from c_toolchain().
-# If `variant_suffix` is defined here, terminal targets in the environment
-# will have "$target_name$variant_suffix" aliases that get the same thing
-# but in that particular variant installed under the suffixed name.
-# The default `variant_suffix` is ".$variant" in each variant.
+# - Optional: A scope imported into the $toolchain scope in these
+# toolchains. This can store useful toolchain-specific variables that
+# should be available within the toolchain. $toolchain automatically
+# contains `tool_dir`, `tool_prefix`, `cc, and `cxx`, from
+# c_toolchain(). If `variant_suffix` is defined here, terminal targets
+# in the environment will have "$target_name$variant_suffix" aliases
+# that get the same thing but in that particular variant installed
+# under the suffixed name. The default `variant_suffix` is ".$variant"
+# in each variant.
+#
+# * variant_libprefix
+# - Optional: If true, each variant's name is used to form the
+# ${toolchain.libprefix} value in that variant. The final libprefix
+# is "${toolchain_vars.libprefix}${toolchain.variant}/". By default,
+# this is true *only* in variants that have the "instrumented" tag.
+# If explicitly set to true or false, that applies to *all* variants.
+# - Type: bool
#
# * variant_selectors
# - Optional: A list in the schema of the $variants build argument. This
@@ -324,7 +337,7 @@ declare_args() {
# .variant scope. If any of these strings appears in a .variant scope,
# then $variant_selectors elements using that variant will be silently
# ignored in this environment's toolchains. e.g. an environment that is
-# incompatbile with instrumentation could list the "instrumentation" tag
+# incompatbile with instrumentation could list the "instrumented" tag
# and variants that enable instrumentation will be defined with that tag.
# Then simple `variants=["asan"]` user configurations that would apply
# ordinarily to all targets don't break the special-case execution
@@ -905,15 +918,21 @@ template("environment") {
# `variant`, so it can't be used any more in this block.)
variant = variant.name
+ if (!defined(libprefix)) {
+ libprefix = ""
+ }
+ if ((defined(invoker.variant_libprefix) &&
+ invoker.variant_libprefix) ||
+ (!defined(invoker.variant_libprefix) &&
+ tags + [ "instrumented" ] - [ "instrumented" ] != tags)) {
+ libprefix += "$variant/"
+ }
+
# Plumb through the suffix of this variant and the list of others.
if (!defined(variant_suffix)) {
variant_suffix = ".$variant"
}
- if (!defined(libprefix)) {
- libprefix = ""
- }
-
other_variants = []
foreach(other_variant, toolchain_variants) {
if (other_variant.name != variant) {
diff --git a/zircon/third_party/ulib/musl/ldso/BUILD.gn b/zircon/third_party/ulib/musl/ldso/BUILD.gn
index 71b4c4da4c6..493979e2840 100644
--- a/zircon/third_party/ulib/musl/ldso/BUILD.gn
+++ b/zircon/third_party/ulib/musl/ldso/BUILD.gn
@@ -13,4 +13,11 @@ source_set("ldso") {
"dynlink-sancov.S",
"dynlink.c",
]
+ if (toolchain.libprefix != "") {
+ # The libprefix always ends with a / but that's not part of the
+ # "config" string in the loader-service protocol.
+ ldsvc_config = get_path_info("${toolchain.libprefix}libfoo.so", "dir")
+ assert(ldsvc_config != "" && ldsvc_config != ".")
+ defines = [ "DYNLINK_LDSVC_CONFIG=\"$ldsvc_config\"" ]
+ }
}
diff --git a/zircon/third_party/ulib/musl/ldso/dynlink.c b/zircon/third_party/ulib/musl/ldso/dynlink.c
index ee8d26fad67..bf724807676 100644
--- a/zircon/third_party/ulib/musl/ldso/dynlink.c
+++ b/zircon/third_party/ulib/musl/ldso/dynlink.c
@@ -2090,6 +2090,11 @@ __NO_SAFESTACK NO_ASAN static dl_start_return_t __dls3(void* start_arg) {
__NO_SAFESTACK NO_ASAN static void early_init(void) {
#if __has_feature(address_sanitizer)
__asan_early_init();
+#endif
+#ifdef DYNLINK_LDSVC_CONFIG
+ // Inform the loader service to look for libraries of the right variant.
+ loader_svc_config(DYNLINK_LDSVC_CONFIG);
+#elif __has_feature(address_sanitizer)
// Inform the loader service that we prefer ASan-supporting libraries.
loader_svc_config("asan");
#endif
--
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