diff options
Diffstat (limited to 'compiler/rustc_driver_impl/src')
| -rw-r--r-- | compiler/rustc_driver_impl/src/lib.rs | 75 | ||||
| -rw-r--r-- | compiler/rustc_driver_impl/src/signal_handler.rs | 76 |
2 files changed, 85 insertions, 66 deletions
diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs index 2e26ce111f0..026dfd8ee90 100644 --- a/compiler/rustc_driver_impl/src/lib.rs +++ b/compiler/rustc_driver_impl/src/lib.rs @@ -78,6 +78,15 @@ pub mod pretty; #[macro_use] mod print; mod session_diagnostics; +#[cfg(all(unix, any(target_env = "gnu", target_os = "macos")))] +mod signal_handler; + +#[cfg(not(all(unix, any(target_env = "gnu", target_os = "macos"))))] +mod signal_handler { + /// On platforms which don't support our signal handler's requirements, + /// simply use the default signal handler provided by std. + pub(super) fn install() {} +} use crate::session_diagnostics::{ RLinkEmptyVersionNumber, RLinkEncodingVersionMismatch, RLinkRustcVersionMismatch, @@ -1427,72 +1436,6 @@ pub fn init_env_logger(handler: &EarlyErrorHandler, env: &str) { } } -#[cfg(all(unix, any(target_env = "gnu", target_os = "macos")))] -mod signal_handler { - extern "C" { - fn backtrace_symbols_fd( - buffer: *const *mut libc::c_void, - size: libc::c_int, - fd: libc::c_int, - ); - } - - extern "C" fn print_stack_trace(_: libc::c_int) { - const MAX_FRAMES: usize = 256; - static mut STACK_TRACE: [*mut libc::c_void; MAX_FRAMES] = - [std::ptr::null_mut(); MAX_FRAMES]; - unsafe { - let depth = libc::backtrace(STACK_TRACE.as_mut_ptr(), MAX_FRAMES as i32); - if depth == 0 { - return; - } - backtrace_symbols_fd(STACK_TRACE.as_ptr(), depth, 2); - } - } - - /// When an error signal (such as SIGABRT or SIGSEGV) is delivered to the - /// process, print a stack trace and then exit. - pub(super) fn install() { - use std::alloc::{alloc, Layout}; - - unsafe { - let alt_stack_size: usize = min_sigstack_size() + 64 * 1024; - let mut alt_stack: libc::stack_t = std::mem::zeroed(); - alt_stack.ss_sp = alloc(Layout::from_size_align(alt_stack_size, 1).unwrap()).cast(); - alt_stack.ss_size = alt_stack_size; - libc::sigaltstack(&alt_stack, std::ptr::null_mut()); - - let mut sa: libc::sigaction = std::mem::zeroed(); - sa.sa_sigaction = print_stack_trace as libc::sighandler_t; - sa.sa_flags = libc::SA_NODEFER | libc::SA_RESETHAND | libc::SA_ONSTACK; - libc::sigemptyset(&mut sa.sa_mask); - libc::sigaction(libc::SIGSEGV, &sa, std::ptr::null_mut()); - } - } - - /// Modern kernels on modern hardware can have dynamic signal stack sizes. - #[cfg(any(target_os = "linux", target_os = "android"))] - fn min_sigstack_size() -> usize { - const AT_MINSIGSTKSZ: core::ffi::c_ulong = 51; - let dynamic_sigstksz = unsafe { libc::getauxval(AT_MINSIGSTKSZ) }; - // If getauxval couldn't find the entry, it returns 0, - // so take the higher of the "constant" and auxval. - // This transparently supports older kernels which don't provide AT_MINSIGSTKSZ - libc::MINSIGSTKSZ.max(dynamic_sigstksz as _) - } - - /// Not all OS support hardware where this is needed. - #[cfg(not(any(target_os = "linux", target_os = "android")))] - fn min_sigstack_size() -> usize { - libc::MINSIGSTKSZ - } -} - -#[cfg(not(all(unix, any(target_env = "gnu", target_os = "macos"))))] -mod signal_handler { - pub(super) fn install() {} -} - pub fn main() -> ! { let start_time = Instant::now(); let start_rss = get_resident_set_size(); diff --git a/compiler/rustc_driver_impl/src/signal_handler.rs b/compiler/rustc_driver_impl/src/signal_handler.rs new file mode 100644 index 00000000000..1bf5c5af866 --- /dev/null +++ b/compiler/rustc_driver_impl/src/signal_handler.rs @@ -0,0 +1,76 @@ +//! Signal handler for rustc +//! Primarily used to extract a backtrace from stack overflow + +use std::alloc::{alloc, Layout}; +use std::{mem, ptr}; + +extern "C" { + fn backtrace_symbols_fd(buffer: *const *mut libc::c_void, size: libc::c_int, fd: libc::c_int); +} + +/// Signal handler installed for SIGSEGV +extern "C" fn print_stack_trace(_: libc::c_int) { + const MAX_FRAMES: usize = 256; + // Reserve data segment so we don't have to malloc in a signal handler, which might fail + // in incredibly undesirable and unexpected ways due to e.g. the allocator deadlocking + static mut STACK_TRACE: [*mut libc::c_void; MAX_FRAMES] = [ptr::null_mut(); MAX_FRAMES]; + unsafe { + // Collect return addresses + let depth = libc::backtrace(STACK_TRACE.as_mut_ptr(), MAX_FRAMES as i32); + if depth == 0 { + return; + } + // Just a stack trace is cryptic. Explain what we're doing. + write_raw_err("error: rustc interrupted by SIGSEGV, printing stack trace:\n\n"); + // Elaborate return addrs into symbols and write them directly to stderr + backtrace_symbols_fd(STACK_TRACE.as_ptr(), depth, libc::STDERR_FILENO); + if depth > 22 { + // We probably just scrolled that "we got SIGSEGV" message off the terminal + write_raw_err("\nerror: stack trace dumped due to SIGSEGV, possible stack overflow"); + }; + write_raw_err("\nerror: please report a bug to https://github.com/rust-lang/rust\n"); + } +} + +/// Write without locking stderr. +/// +/// Only acceptable because everything will end soon anyways. +fn write_raw_err(input: &str) { + // We do not care how many bytes we actually get out. SIGSEGV comes for our head. + // Splash stderr with letters of our own blood to warn our friends about the monster. + let _ = unsafe { libc::write(libc::STDERR_FILENO, input.as_ptr().cast(), input.len()) }; +} + +/// When SIGSEGV is delivered to the process, print a stack trace and then exit. +pub(super) fn install() { + unsafe { + let alt_stack_size: usize = min_sigstack_size() + 64 * 1024; + let mut alt_stack: libc::stack_t = mem::zeroed(); + alt_stack.ss_sp = alloc(Layout::from_size_align(alt_stack_size, 1).unwrap()).cast(); + alt_stack.ss_size = alt_stack_size; + libc::sigaltstack(&alt_stack, ptr::null_mut()); + + let mut sa: libc::sigaction = mem::zeroed(); + sa.sa_sigaction = print_stack_trace as libc::sighandler_t; + sa.sa_flags = libc::SA_NODEFER | libc::SA_RESETHAND | libc::SA_ONSTACK; + libc::sigemptyset(&mut sa.sa_mask); + libc::sigaction(libc::SIGSEGV, &sa, ptr::null_mut()); + } +} + +/// Modern kernels on modern hardware can have dynamic signal stack sizes. +#[cfg(any(target_os = "linux", target_os = "android"))] +fn min_sigstack_size() -> usize { + const AT_MINSIGSTKSZ: core::ffi::c_ulong = 51; + let dynamic_sigstksz = unsafe { libc::getauxval(AT_MINSIGSTKSZ) }; + // If getauxval couldn't find the entry, it returns 0, + // so take the higher of the "constant" and auxval. + // This transparently supports older kernels which don't provide AT_MINSIGSTKSZ + libc::MINSIGSTKSZ.max(dynamic_sigstksz as _) +} + +/// Not all OS support hardware where this is needed. +#[cfg(not(any(target_os = "linux", target_os = "android")))] +fn min_sigstack_size() -> usize { + libc::MINSIGSTKSZ +} |