Prefix our own symbols we build

Author: alexcrichton

backtrace-sys/build.rs

@@ -2,9 +2,17 @@ extern crate gcc;
 
 use std::env;
 use std::ffi::OsString;
+use std::fs;
 use std::path::PathBuf;
 use std::process::Command;
 
+macro_rules! t {
+    ($e:expr) => (match $e {
+        Ok(e) => e,
+        Err(e) => panic!("{} failed with {}", stringify!($e), e),
+    })
+}
+
 fn main() {
     let src = env::current_dir().unwrap();
     let dst = PathBuf::from(env::var_os("OUT_DIR").unwrap());
@@ -21,11 +29,6 @@ fn main() {
         return
     }
 
-    // libbacktrace is already included in the linux libstd for rust
-    if target.contains("linux") {
-        return
-    }
-
     // no way this will ever compile for emscripten
     if target.contains("emscripten") {
         return
@@ -56,6 +59,29 @@ fn main() {
                              src.join("src/libbacktrace").display())));
     println!("cargo:rustc-link-search=native={}/.libs", dst.display());
     println!("cargo:rustc-link-lib=static=backtrace");
+
+    // The standard library currently bundles in libbacktrace, but it's
+    // compiled with hidden visibility (naturally) so we can't use it.
+    //
+    // To prevent conflicts with a second statically linked copy we rename all
+    // symbols with a '__rbt_' prefix manually here through `objcopy`.
+    let lib = dst.join(".libs/libbacktrace.a");
+    let tmpdir = dst.join("__tmp");
+    drop(fs::remove_dir_all(&tmpdir));
+    t!(fs::create_dir_all(&tmpdir));
+    run(Command::new("ar").arg("x").arg(&lib).current_dir(&tmpdir));
+
+    t!(fs::remove_file(&lib));
+    let mut objs = Vec::new();
+    for obj in t!(tmpdir.read_dir()) {
+        let obj = t!(obj);
+        run(Command::new("objcopy")
+                    .arg("--redefine-syms=symbol-map")
+                    .arg(obj.path()));
+        objs.push(obj.path());
+    }
+
+    run(Command::new("ar").arg("crus").arg(&lib).args(&objs));
 }
 
 fn run(cmd: &mut Command) {

backtrace-sys/src/lib.rs

@@ -24,15 +24,18 @@ pub type backtrace_error_callback =
 pub enum backtrace_state {}
 
 extern {
+    #[link_name = "__rbt_backtrace_create_state"]
     pub fn backtrace_create_state(filename: *const c_char,
                                   threaded: c_int,
                                   error: backtrace_error_callback,
                                   data: *mut c_void) -> *mut backtrace_state;
+    #[link_name = "__rbt_backtrace_syminfo"]
     pub fn backtrace_syminfo(state: *mut backtrace_state,
                              addr: uintptr_t,
                              cb: backtrace_syminfo_callback,
                              error: backtrace_error_callback,
                              data: *mut c_void) -> c_int;
+    #[link_name = "__rbt_backtrace_pcinfo"]
     pub fn backtrace_pcinfo(state: *mut backtrace_state,
                             addr: uintptr_t,
                             cb: backtrace_full_callback,

backtrace-sys/symbol-map

@@ -0,0 +1,18 @@
+backtrace_full __rbt_backtrace_full
+backtrace_dwarf_add __rbt_backtrace_dwarf_add
+backtrace_initialize __rbt_backtrace_initialize
+backtrace_pcinfo __rbt_backtrace_pcinfo
+backtrace_syminfo __rbt_backtrace_syminfo
+backtrace_get_view __rbt_backtrace_get_view
+backtrace_release_view __rbt_backtrace_release_view
+backtrace_alloc __rbt_backtrace_alloc
+backtrace_free __rbt_backtrace_free
+backtrace_vector_finish __rbt_backtrace_vector_finish
+backtrace_vector_grow __rbt_backtrace_vector_grow
+backtrace_vector_release __rbt_backtrace_vector_release
+backtrace_close __rbt_backtrace_close
+backtrace_open __rbt_backtrace_open
+backtrace_print __rbt_backtrace_print
+backtrace_simple __rbt_backtrace_simple
+backtrace_qsort __rbt_backtrace_qsort
+backtrace_create_state __rbt_backtrace_create_state