From 86d1678403a46cd30019487dcc21166c1d09a597 Mon Sep 17 00:00:00 2001
From: Petr Hosek <phosek@google.com>
Date: Sun, 10 Mar 2019 19:27:59 -0700
Subject: [PATCH] Support using LLVM's libunwind as the unwinder implementation
This avoids the dependency on host libraries such as libgcc_s which
may be undesirable in some deployment environments where these aren't
available.
---
Cargo.lock | 1 +
config.toml.example | 3 ++
src/bootstrap/config.rs | 3 ++
src/bootstrap/configure.py | 2 ++
src/bootstrap/lib.rs | 3 ++
src/libstd/Cargo.toml | 1 +
src/libunwind/Cargo.toml | 9 +++++
src/libunwind/build.rs | 67 +++++++++++++++++++++++++++++++++++++-
src/llvm-project | 2 +-
9 files changed, 89 insertions(+), 2 deletions(-)
diff --git a/Cargo.lock b/Cargo.lock
index c7007017078e6..4a71884cb086e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3849,6 +3849,7 @@ dependencies = [
name = "unwind"
version = "0.0.0"
dependencies = [
+ "cc 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
"compiler_builtins 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
"core 0.0.0",
"libc 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/config.toml.example b/config.toml.example
index 5e0a2fbf0d373..8b2153cd2e63c 100644
--- a/config.toml.example
+++ b/config.toml.example
@@ -421,6 +421,9 @@
# development of NLL
#test-compare-mode = false
+# Use LLVM libunwind as the implementation for Rust's unwinder.
+#llvm-libunwind = false
+
# =============================================================================
# Options for specific targets
#
diff --git a/src/bootstrap/config.rs b/src/bootstrap/config.rs
index cb71550c12d4d..0c31c41ceda86 100644
--- a/src/bootstrap/config.rs
+++ b/src/bootstrap/config.rs
@@ -48,6 +48,7 @@ pub struct Config {
pub exclude: Vec<PathBuf>,
pub rustc_error_format: Option<String>,
pub test_compare_mode: bool,
+ pub llvm_libunwind: bool,
pub run_host_only: bool,
@@ -329,6 +330,7 @@ struct Rust {
remap_debuginfo: Option<bool>,
jemalloc: Option<bool>,
test_compare_mode: Option<bool>,
+ llvm_libunwind: Option<bool>,
}
/// TOML representation of how each build target is configured.
@@ -548,6 +550,7 @@ impl Config {
set(&mut config.rust_rpath, rust.rpath);
set(&mut config.jemalloc, rust.jemalloc);
set(&mut config.test_compare_mode, rust.test_compare_mode);
+ set(&mut config.llvm_libunwind, rust.llvm_libunwind);
set(&mut config.backtrace, rust.backtrace);
set(&mut config.channel, rust.channel.clone());
set(&mut config.rust_dist_src, rust.dist_src);
diff --git a/src/bootstrap/configure.py b/src/bootstrap/configure.py
index b2d8f2d8ebfcf..ade8afee7c109 100755
--- a/src/bootstrap/configure.py
+++ b/src/bootstrap/configure.py
@@ -68,6 +68,8 @@ def v(*args):
o("cxxflags", "llvm.cxxflags", "build LLVM with these extra compiler flags")
o("ldflags", "llvm.ldflags", "build LLVM with these extra linker flags")
+o("llvm-libunwind", "rust.llvm_libunwind", "use LLVM libunwind")
+
# Optimization and debugging options. These may be overridden by the release
# channel, etc.
o("optimize", "rust.optimize", "build optimized rust code")
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 47ac04baf6d6d..bcd28e9cf5e70 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -506,6 +506,9 @@ impl Build {
fn std_features(&self) -> String {
let mut features = "panic-unwind".to_string();
+ if self.config.llvm_libunwind {
+ features.push_str(" llvm-libunwind");
+ }
if self.config.backtrace {
features.push_str(" backtrace");
}
diff --git a/src/libstd/Cargo.toml b/src/libstd/Cargo.toml
index 9ac03adfc2778..875483518e872 100644
--- a/src/libstd/Cargo.toml
+++ b/src/libstd/Cargo.toml
@@ -54,6 +54,7 @@ backtrace = ["backtrace-sys"]
panic-unwind = ["panic_unwind"]
profiler = ["profiler_builtins"]
compiler_builtins_c = ["compiler_builtins/c"]
+llvm-libunwind = ["unwind/llvm-libunwind"]
# Make panics and failed asserts immediately abort without formatting any message
panic_immediate_abort = ["core/panic_immediate_abort"]
diff --git a/src/libunwind/Cargo.toml b/src/libunwind/Cargo.toml
index 2378b0a315a16..4ddc878997ee5 100644
--- a/src/libunwind/Cargo.toml
+++ b/src/libunwind/Cargo.toml
@@ -4,6 +4,9 @@ name = "unwind"
version = "0.0.0"
build = "build.rs"
edition = "2018"
+include = [
+ '/libunwind/*',
+]
[lib]
name = "unwind"
@@ -16,3 +19,9 @@ doc = false
core = { path = "../libcore" }
libc = { version = "0.2.43", features = ['rustc-dep-of-std'], default-features = false }
compiler_builtins = "0.1.0"
+
+[build-dependencies]
+cc = { optional = true, version = "1.0.1" }
+
+[features]
+llvm-libunwind = ["cc"]
diff --git a/src/libunwind/build.rs b/src/libunwind/build.rs
index b50a11fa03ab6..f3fda9eaa75f4 100644
--- a/src/libunwind/build.rs
+++ b/src/libunwind/build.rs
@@ -4,7 +4,13 @@ fn main() {
println!("cargo:rerun-if-changed=build.rs");
let target = env::var("TARGET").expect("TARGET was not set");
- if target.contains("linux") {
+ if cfg!(feature = "llvm-libunwind") &&
+ (target.contains("linux") ||
+ target.contains("fuchsia")) {
+ // Build the unwinding from libunwind C/C++ source code.
+ #[cfg(feature = "llvm-libunwind")]
+ llvm_libunwind::compile();
+ } else if target.contains("linux") {
if target.contains("musl") {
// musl is handled in lib.rs
} else if !target.contains("android") {
@@ -37,3 +43,62 @@ fn main() {
println!("cargo:rustc-link-lib=unwind");
}
}
+
+#[cfg(feature = "llvm-libunwind")]
+mod llvm_libunwind {
+ use std::env;
+ use std::path::Path;
+
+ /// Compile the libunwind C/C++ source code.
+ pub fn compile() {
+ let target_env = env::var("CARGO_CFG_TARGET_ENV").unwrap();
+ let target_vendor = env::var("CARGO_CFG_TARGET_VENDOR").unwrap();
+ let cfg = &mut cc::Build::new();
+
+ cfg.cpp(true);
+ cfg.cpp_set_stdlib(None);
+ cfg.warnings(false);
+
+ 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 {
+ cfg.flag("-std=c99");
+ cfg.flag("-std=c++11");
+ cfg.flag("-nostdinc++");
+ if cfg.is_flag_supported("-funwind-tables").unwrap_or_default() &&
+ cfg.is_flag_supported("-fno-exceptions").unwrap_or_default() {
+ cfg.flag("-funwind-tables");
+ cfg.flag("-fno-exceptions");
+ }
+ cfg.flag("-fno-rtti");
+ cfg.flag("-fstrict-aliasing");
+ }
+
+ let mut unwind_sources = vec![
+ "Unwind-EHABI.cpp",
+ "Unwind-seh.cpp",
+ "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 root = Path::new("../llvm-project/libunwind");
+ cfg.include(root.join("include"));
+ for src in unwind_sources {
+ cfg.file(root.join("src").join(src));
+ }
+
+ cfg.compile("unwind");
+ }
+}
diff --git a/src/llvm-project b/src/llvm-project
index 1f484cbe0e863..84abffda0e03b 160000
--- a/src/llvm-project
+++ b/src/llvm-project
@@ -1 +1 @@
-Subproject commit 1f484cbe0e863e9e215f1b3d7198063444d60873
+Subproject commit 84abffda0e03b03c62bdfc3cfeda1c2cf1f88c85