From 52a33655be8f2afc1ac666d24b5850badb23b3e7 Mon Sep 17 00:00:00 2001 From: 12101111 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" {}