From 52a33655be8f2afc1ac666d24b5850badb23b3e7 Mon Sep 17 00:00:00 2001
From: 12101111 <w12101111@gmail.com>
Date: Mon, 24 May 2021 17:53:09 +0800
Subject: [PATCH] cleanup and fix compiling of libunwind
fix conditional compiling of llvm-libunwind feaure for musl target.
update document of llvm-libunwind feature.
---
config.toml.example | 8 +++
library/unwind/Cargo.toml | 7 ++
library/unwind/build.rs | 144 +++++++++++++++++++-------------------
library/unwind/src/lib.rs | 21 ++++--
4 files changed, 105 insertions(+), 75 deletions(-)
diff --git a/config.toml.example b/config.toml.example
index 16952a5ced8..df2fb448b7d 100644
--- a/config.toml.example
+++ b/config.toml.example
@@ -563,6 +563,14 @@ changelog-seen = 2
# Use LLVM libunwind as the implementation for Rust's unwinder.
# Accepted values are 'in-tree' (formerly true), 'system' or 'no' (formerly false).
+# This option only applies for Linux and Fuchsia targets.
+# On Linux target, if crt-static is not enabled, 'no' means dynamic link to
+# `libgcc_s.so`, 'in-tree' means static link to the in-tree build of llvm libunwind
+# and 'system' means dynamic link to `libunwind.so`. If crt-static is enabled,
+# the behavior is depend on the libc. On musl target, 'no' and 'in-tree' both
+# means static link to the in-tree build of llvm libunwind, and 'system' means
+# static link to `libunwind.a` provided by system. Due to the limitation of glibc,
+# it must link to `libgcc_eh.a` to get a working output, and this option have no effect.
#llvm-libunwind = 'no'
# Enable Windows Control Flow Guard checks in the standard library.
diff --git a/library/unwind/Cargo.toml b/library/unwind/Cargo.toml
index f42ded62585..9273ad0c3a4 100644
--- a/library/unwind/Cargo.toml
+++ b/library/unwind/Cargo.toml
@@ -24,5 +24,12 @@ cfg-if = "0.1.8"
cc = "1.0.67"
[features]
+
+# Only applies for Linux and Fuchsia targets
+# Static link to the in-tree build of llvm libunwind
llvm-libunwind = []
+
+# Only applies for Linux and Fuchsia targets
+# If crt-static is enabled, static link to `libunwind.a` provided by system
+# If crt-static is disabled, dynamic link to `libunwind.so` provided by system
system-llvm-libunwind = []
diff --git a/library/unwind/build.rs b/library/unwind/build.rs
index d8bf152e4d6..96df3fc5ac4 100644
--- a/library/unwind/build.rs
+++ b/library/unwind/build.rs
@@ -4,7 +4,8 @@ fn main() {
println!("cargo:rerun-if-changed=build.rs");
let target = env::var("TARGET").expect("TARGET was not set");
- if cfg!(feature = "system-llvm-libunwind") {
+ if cfg!(target_os = "linux") && cfg!(feature = "system-llvm-libunwind") {
+ // linking for Linux is handled in lib.rs
return;
}
@@ -57,101 +58,102 @@ mod llvm_libunwind {
pub fn compile() {
let target = env::var("TARGET").expect("TARGET was not set");
let target_env = env::var("CARGO_CFG_TARGET_ENV").unwrap();
- let target_vendor = env::var("CARGO_CFG_TARGET_VENDOR").unwrap();
- let target_endian_little = env::var("CARGO_CFG_TARGET_ENDIAN").unwrap() != "big";
- let cfg = &mut cc::Build::new();
+ let mut cc_cfg = cc::Build::new();
+ let mut cpp_cfg = cc::Build::new();
+ let root = Path::new("../../src/llvm-project/libunwind");
- cfg.cpp(true);
- cfg.cpp_set_stdlib(None);
- cfg.warnings(false);
+ cpp_cfg.cpp(true);
+ cpp_cfg.cpp_set_stdlib(None);
+ cpp_cfg.flag("-nostdinc++");
+ cpp_cfg.flag("-fno-exceptions");
+ cpp_cfg.flag("-fno-rtti");
+ cpp_cfg.flag_if_supported("-fvisibility-global-new-delete-hidden");
- // libunwind expects a __LITTLE_ENDIAN__ macro to be set for LE archs, cf. #65765
- if target_endian_little {
- cfg.define("__LITTLE_ENDIAN__", Some("1"));
+ // Don't set this for clang
+ // By default, Clang builds C code in GNU C17 mode.
+ // By default, Clang builds C++ code according to the C++98 standard,
+ // with many C++11 features accepted as extensions.
+ if cpp_cfg.get_compiler().is_like_gnu() {
+ cpp_cfg.flag("-std=c++11");
+ cc_cfg.flag("-std=c99");
}
- if target_env == "msvc" {
- // Don't pull in extra libraries on MSVC
- cfg.flag("/Zl");
- cfg.flag("/EHsc");
- cfg.define("_CRT_SECURE_NO_WARNINGS", None);
- cfg.define("_LIBUNWIND_DISABLE_VISIBILITY_ANNOTATIONS", None);
- } else if target.contains("x86_64-fortanix-unknown-sgx") {
- cfg.cpp(false);
+ if target.contains("x86_64-fortanix-unknown-sgx") || target_env == "musl" {
+ // use the same GCC C compiler command to compile C++ code so we do not need to setup the
+ // C++ compiler env variables on the builders.
+ // Don't set this for clang++, as clang++ is able to compile this without libc++.
+ if cpp_cfg.get_compiler().is_like_gnu() {
+ cpp_cfg.cpp(false);
+ }
+ }
- cfg.static_flag(true);
- cfg.opt_level(3);
-
- cfg.flag("-nostdinc++");
- cfg.flag("-fno-exceptions");
- cfg.flag("-fno-rtti");
+ for cfg in [&mut cc_cfg, &mut cpp_cfg].iter_mut() {
+ cfg.warnings(false);
cfg.flag("-fstrict-aliasing");
cfg.flag("-funwind-tables");
cfg.flag("-fvisibility=hidden");
- cfg.flag("-fno-stack-protector");
- cfg.flag("-ffreestanding");
- cfg.flag("-fexceptions");
-
- // easiest way to undefine since no API available in cc::Build to undefine
- cfg.flag("-U_FORTIFY_SOURCE");
- cfg.define("_FORTIFY_SOURCE", "0");
-
- cfg.flag_if_supported("-fvisibility-global-new-delete-hidden");
-
- cfg.define("_LIBUNWIND_DISABLE_VISIBILITY_ANNOTATIONS", None);
- cfg.define("RUST_SGX", "1");
- cfg.define("__NO_STRING_INLINES", None);
- cfg.define("__NO_MATH_INLINES", None);
- cfg.define("_LIBUNWIND_IS_BAREMETAL", None);
- cfg.define("__LIBUNWIND_IS_NATIVE_ONLY", None);
- cfg.define("NDEBUG", None);
- } else {
- cfg.flag("-std=c99");
- cfg.flag("-std=c++11");
- cfg.flag("-nostdinc++");
- cfg.flag("-fno-exceptions");
- cfg.flag("-fno-rtti");
- cfg.flag("-fstrict-aliasing");
- cfg.flag("-funwind-tables");
- cfg.flag("-fvisibility=hidden");
- cfg.flag_if_supported("-fvisibility-global-new-delete-hidden");
cfg.define("_LIBUNWIND_DISABLE_VISIBILITY_ANNOTATIONS", None);
+ cfg.include(root.join("include"));
+ cfg.cargo_metadata(false);
+
+ if target.contains("x86_64-fortanix-unknown-sgx") {
+ cfg.static_flag(true);
+ cfg.opt_level(3);
+ cfg.flag("-fno-stack-protector");
+ cfg.flag("-ffreestanding");
+ cfg.flag("-fexceptions");
+
+ // easiest way to undefine since no API available in cc::Build to undefine
+ cfg.flag("-U_FORTIFY_SOURCE");
+ cfg.define("_FORTIFY_SOURCE", "0");
+ cfg.define("RUST_SGX", "1");
+ cfg.define("__NO_STRING_INLINES", None);
+ cfg.define("__NO_MATH_INLINES", None);
+ cfg.define("_LIBUNWIND_IS_BAREMETAL", None);
+ cfg.define("__LIBUNWIND_IS_NATIVE_ONLY", None);
+ cfg.define("NDEBUG", None);
+ }
}
- let mut unwind_sources = vec![
- "Unwind-EHABI.cpp",
- "Unwind-seh.cpp",
+ let mut c_sources = vec![
"Unwind-sjlj.c",
"UnwindLevel1-gcc-ext.c",
"UnwindLevel1.c",
"UnwindRegistersRestore.S",
"UnwindRegistersSave.S",
- "libunwind.cpp",
];
- if target_vendor == "apple" {
- unwind_sources.push("Unwind_AppleExtras.cpp");
- }
+ let cpp_sources = vec!["Unwind-EHABI.cpp", "Unwind-seh.cpp", "libunwind.cpp"];
+ let cpp_len = cpp_sources.len();
if target.contains("x86_64-fortanix-unknown-sgx") {
- unwind_sources.push("UnwindRustSgx.c");
+ c_sources.push("UnwindRustSgx.c");
}
- let root = Path::new("../../src/llvm-project/libunwind");
- cfg.include(root.join("include"));
- for src in unwind_sources {
- cfg.file(root.join("src").join(src));
+ for src in c_sources {
+ cc_cfg.file(root.join("src").join(src).canonicalize().unwrap());
}
- if target_env == "musl" {
- // use the same C compiler command to compile C++ code so we do not need to setup the
- // C++ compiler env variables on the builders
- cfg.cpp(false);
- // linking for musl is handled in lib.rs
- cfg.cargo_metadata(false);
- println!("cargo:rustc-link-search=native={}", env::var("OUT_DIR").unwrap());
+ for src in cpp_sources {
+ cpp_cfg.file(root.join("src").join(src).canonicalize().unwrap());
}
- cfg.compile("unwind");
+ let out_dir = env::var("OUT_DIR").unwrap();
+ println!("cargo:rustc-link-search=native={}", &out_dir);
+
+ cpp_cfg.compile("unwind-cpp");
+
+ let mut count = 0;
+ for entry in std::fs::read_dir(&out_dir).unwrap() {
+ let obj = entry.unwrap().path().canonicalize().unwrap();
+ if let Some(ext) = obj.extension() {
+ if ext == "o" {
+ cc_cfg.object(&obj);
+ count += 1;
+ }
+ }
+ }
+ assert_eq!(cpp_len, count, "Can't get object files from {:?}", &out_dir);
+ cc_cfg.compile("unwind");
}
}
diff --git a/library/unwind/src/lib.rs b/library/unwind/src/lib.rs
index be5e56c71e3..eaeec72fbb5 100644
--- a/library/unwind/src/lib.rs
+++ b/library/unwind/src/lib.rs
@@ -37,9 +37,22 @@ cfg_if::cfg_if! {
}
#[cfg(target_env = "musl")]
-#[link(name = "unwind", kind = "static", cfg(target_feature = "crt-static"))]
-#[link(name = "gcc_s", cfg(not(target_feature = "crt-static")))]
-extern "C" {}
+cfg_if::cfg_if! {
+ if #[cfg(all(feature = "llvm-libunwind", feature = "system-llvm-libunwind"))] {
+ compile_error!("`llvm-libunwind` and `system-llvm-libunwind` cannot be enabled at the same time");
+ } else if #[cfg(feature = "llvm-libunwind")] {
+ #[link(name = "unwind", kind = "static")]
+ extern "C" {}
+ } else if #[cfg(feature = "system-llvm-libunwind")] {
+ #[link(name = "unwind", kind = "static-nobundle", cfg(target_feature = "crt-static"))]
+ #[link(name = "unwind", cfg(not(target_feature = "crt-static")))]
+ extern "C" {}
+ } else {
+ #[link(name = "unwind", kind = "static", cfg(target_feature = "crt-static"))]
+ #[link(name = "gcc_s", cfg(not(target_feature = "crt-static")))]
+ extern "C" {}
+ }
+}
// When building with crt-static, we get `gcc_eh` from the `libc` crate, since
// glibc needs it, and needs it listed later on the linker command line. We
@@ -68,5 +81,5 @@ extern "C" {}
extern "C" {}
#[cfg(all(target_vendor = "fortanix", target_env = "sgx"))]
-#[link(name = "unwind", kind = "static-nobundle")]
+#[link(name = "unwind", kind = "static")]
extern "C" {}