Merging upstream version 1.74.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 165 insertions, 126 deletions

diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index 736877bde..65c7aed3f 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -85,6 +85,15 @@ 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,
@@ -140,12 +149,6 @@ pub const EXIT_FAILURE: i32 = 1;
 pub const DEFAULT_BUG_REPORT_URL: &str = "https://github.com/rust-lang/rust/issues/new\
     ?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md";
 
-const ICE_REPORT_COMPILER_FLAGS: &[&str] = &["-Z", "-C", "--crate-type"];
-
-const ICE_REPORT_COMPILER_FLAGS_EXCLUDE: &[&str] = &["metadata", "extra-filename"];
-
-const ICE_REPORT_COMPILER_FLAGS_STRIP_VALUE: &[&str] = &["incremental"];
-
 pub fn abort_on_err<T>(result: Result<T, ErrorGuaranteed>, sess: &Session) -> T {
     match result {
         Err(..) => {
@@ -159,9 +162,10 @@ pub fn abort_on_err<T>(result: Result<T, ErrorGuaranteed>, sess: &Session) -> T
 pub trait Callbacks {
     /// Called before creating the compiler instance
     fn config(&mut self, _config: &mut interface::Config) {}
-    /// Called after parsing. Return value instructs the compiler whether to
+    /// Called after parsing the crate root. Submodules are not yet parsed when
+    /// this callback is called. Return value instructs the compiler whether to
     /// continue the compilation afterwards (defaults to `Compilation::Continue`)
-    fn after_parsing<'tcx>(
+    fn after_crate_root_parsing<'tcx>(
         &mut self,
         _compiler: &interface::Compiler,
         _queries: &'tcx Queries<'tcx>,
@@ -181,7 +185,6 @@ pub trait Callbacks {
     /// continue the compilation afterwards (defaults to `Compilation::Continue`)
     fn after_analysis<'tcx>(
         &mut self,
-        _handler: &EarlyErrorHandler,
         _compiler: &interface::Compiler,
         _queries: &'tcx Queries<'tcx>,
     ) -> Compilation {
@@ -310,6 +313,7 @@ fn run_compiler(
         override_queries: None,
         make_codegen_backend,
         registry: diagnostics_registry(),
+        expanded_args: args,
     };
 
     match make_input(&early_error_handler, &matches.free) {
@@ -403,7 +407,7 @@ fn run_compiler(
                 return early_exit();
             }
 
-            if callbacks.after_parsing(compiler, queries) == Compilation::Stop {
+            if callbacks.after_crate_root_parsing(compiler, queries) == Compilation::Stop {
                 return early_exit();
             }
 
@@ -441,7 +445,7 @@ fn run_compiler(
 
             queries.global_ctxt()?.enter(|tcx| tcx.analysis(()))?;
 
-            if callbacks.after_analysis(&handler, compiler, queries) == Compilation::Stop {
+            if callbacks.after_analysis(compiler, queries) == Compilation::Stop {
                 return early_exit();
             }
 
@@ -696,12 +700,14 @@ pub fn list_metadata(
     sess: &Session,
     metadata_loader: &dyn MetadataLoader,
 ) -> Compilation {
-    if sess.opts.unstable_opts.ls {
+    let ls_kinds = &sess.opts.unstable_opts.ls;
+    if !ls_kinds.is_empty() {
         match sess.io.input {
             Input::File(ref ifile) => {
                 let path = &(*ifile);
                 let mut v = Vec::new();
-                locator::list_file_metadata(&sess.target, path, metadata_loader, &mut v).unwrap();
+                locator::list_file_metadata(&sess.target, path, metadata_loader, &mut v, ls_kinds)
+                    .unwrap();
                 safe_println!("{}", String::from_utf8(v).unwrap());
             }
             Input::Str { .. } => {
@@ -858,11 +864,9 @@ fn print_crate_info(
                 use rustc_target::spec::current_apple_deployment_target;
 
                 if sess.target.is_like_osx {
-                    println_info!(
-                        "deployment_target={}",
-                        current_apple_deployment_target(&sess.target)
-                            .expect("unknown Apple target OS")
-                    )
+                    let (major, minor) = current_apple_deployment_target(&sess.target)
+                        .expect("unknown Apple target OS");
+                    println_info!("deployment_target={}", format!("{major}.{minor}"))
                 } else {
                     handler
                         .early_error("only Apple targets currently support deployment version info")
@@ -1250,47 +1254,6 @@ fn parse_crate_attrs<'a>(sess: &'a Session) -> PResult<'a, ast::AttrVec> {
     }
 }
 
-/// Gets a list of extra command-line flags provided by the user, as strings.
-///
-/// This function is used during ICEs to show more information useful for
-/// debugging, since some ICEs only happens with non-default compiler flags
-/// (and the users don't always report them).
-fn extra_compiler_flags() -> Option<(Vec<String>, bool)> {
-    let mut args = env::args_os().map(|arg| arg.to_string_lossy().to_string()).peekable();
-
-    let mut result = Vec::new();
-    let mut excluded_cargo_defaults = false;
-    while let Some(arg) = args.next() {
-        if let Some(a) = ICE_REPORT_COMPILER_FLAGS.iter().find(|a| arg.starts_with(*a)) {
-            let content = if arg.len() == a.len() {
-                // A space-separated option, like `-C incremental=foo` or `--crate-type rlib`
-                match args.next() {
-                    Some(arg) => arg.to_string(),
-                    None => continue,
-                }
-            } else if arg.get(a.len()..a.len() + 1) == Some("=") {
-                // An equals option, like `--crate-type=rlib`
-                arg[a.len() + 1..].to_string()
-            } else {
-                // A non-space option, like `-Cincremental=foo`
-                arg[a.len()..].to_string()
-            };
-            let option = content.split_once('=').map(|s| s.0).unwrap_or(&content);
-            if ICE_REPORT_COMPILER_FLAGS_EXCLUDE.iter().any(|exc| option == *exc) {
-                excluded_cargo_defaults = true;
-            } else {
-                result.push(a.to_string());
-                match ICE_REPORT_COMPILER_FLAGS_STRIP_VALUE.iter().find(|s| option == **s) {
-                    Some(s) => result.push(format!("{s}=[REDACTED]")),
-                    None => result.push(content),
-                }
-            }
-        }
-    }
-
-    if !result.is_empty() { Some((result, excluded_cargo_defaults)) } else { None }
-}
-
 /// Runs a closure and catches unwinds triggered by fatal errors.
 ///
 /// The compiler currently unwinds with a special sentinel value to abort
@@ -1477,7 +1440,7 @@ pub fn report_ice(info: &panic::PanicInfo<'_>, bug_report_url: &str, extra_info:
         None
     };
 
-    if let Some((flags, excluded_cargo_defaults)) = extra_compiler_flags() {
+    if let Some((flags, excluded_cargo_defaults)) = rustc_session::utils::extra_compiler_flags() {
         handler.emit_note(session_diagnostics::IceFlags { flags: flags.join(" ") });
         if excluded_cargo_defaults {
             handler.emit_note(session_diagnostics::IceExcludeCargoDefaults);
@@ -1517,72 +1480,6 @@ 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 000000000..deca10822
--- /dev/null
+++ b/compiler/rustc_driver_impl/src/signal_handler.rs
@@ -0,0 +1,142 @@
+//! Signal handler for rustc
+//! Primarily used to extract a backtrace from stack overflow
+
+use std::alloc::{alloc, Layout};
+use std::{fmt, mem, ptr};
+
+extern "C" {
+    fn backtrace_symbols_fd(buffer: *const *mut libc::c_void, size: libc::c_int, fd: libc::c_int);
+}
+
+fn backtrace_stderr(buffer: &[*mut libc::c_void]) {
+    let size = buffer.len().try_into().unwrap_or_default();
+    unsafe { backtrace_symbols_fd(buffer.as_ptr(), size, libc::STDERR_FILENO) };
+}
+
+/// Unbuffered, unsynchronized writer to stderr.
+///
+/// Only acceptable because everything will end soon anyways.
+struct RawStderr(());
+
+impl fmt::Write for RawStderr {
+    fn write_str(&mut self, s: &str) -> Result<(), fmt::Error> {
+        let ret = unsafe { libc::write(libc::STDERR_FILENO, s.as_ptr().cast(), s.len()) };
+        if ret == -1 { Err(fmt::Error) } else { Ok(()) }
+    }
+}
+
+/// We don't really 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.
+macro raw_errln($tokens:tt) {
+    let _ = ::core::fmt::Write::write_fmt(&mut RawStderr(()), format_args!($tokens));
+    let _ = ::core::fmt::Write::write_char(&mut RawStderr(()), '\n');
+}
+
+/// 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];
+    let stack = unsafe {
+        // Collect return addresses
+        let depth = libc::backtrace(STACK_TRACE.as_mut_ptr(), MAX_FRAMES as i32);
+        if depth == 0 {
+            return;
+        }
+        &STACK_TRACE.as_slice()[0..(depth as _)]
+    };
+
+    // Just a stack trace is cryptic. Explain what we're doing.
+    raw_errln!("error: rustc interrupted by SIGSEGV, printing backtrace\n");
+    let mut written = 1;
+    let mut consumed = 0;
+    // Begin elaborating return addrs into symbols and writing them directly to stderr
+    // Most backtraces are stack overflow, most stack overflows are from recursion
+    // Check for cycles before writing 250 lines of the same ~5 symbols
+    let cycled = |(runner, walker)| runner == walker;
+    let mut cyclic = false;
+    if let Some(period) = stack.iter().skip(1).step_by(2).zip(stack).position(cycled) {
+        let period = period.saturating_add(1); // avoid "what if wrapped?" branches
+        let Some(offset) = stack.iter().skip(period).zip(stack).position(cycled) else {
+            // impossible.
+            return;
+        };
+
+        // Count matching trace slices, else we could miscount "biphasic cycles"
+        // with the same period + loop entry but a different inner loop
+        let next_cycle = stack[offset..].chunks_exact(period).skip(1);
+        let cycles = 1 + next_cycle
+            .zip(stack[offset..].chunks_exact(period))
+            .filter(|(next, prev)| next == prev)
+            .count();
+        backtrace_stderr(&stack[..offset]);
+        written += offset;
+        consumed += offset;
+        if cycles > 1 {
+            raw_errln!("\n### cycle encountered after {offset} frames with period {period}");
+            backtrace_stderr(&stack[consumed..consumed + period]);
+            raw_errln!("### recursed {cycles} times\n");
+            written += period + 4;
+            consumed += period * cycles;
+            cyclic = true;
+        };
+    }
+    let rem = &stack[consumed..];
+    backtrace_stderr(rem);
+    raw_errln!("");
+    written += rem.len() + 1;
+
+    let random_depth = || 8 * 16; // chosen by random diceroll (2d20)
+    if cyclic || stack.len() > random_depth() {
+        // technically speculation, but assert it with confidence anyway.
+        // rustc only arrived in this signal handler because bad things happened
+        // and this message is for explaining it's not the programmer's fault
+        raw_errln!("note: rustc unexpectedly overflowed its stack! this is a bug");
+        written += 1;
+    }
+    if stack.len() == MAX_FRAMES {
+        raw_errln!("note: maximum backtrace depth reached, frames may have been lost");
+        written += 1;
+    }
+    raw_errln!("note: we would appreciate a report at https://github.com/rust-lang/rust");
+    written += 1;
+    if written > 24 {
+        // We probably just scrolled the earlier "we got SIGSEGV" message off the terminal
+        raw_errln!("note: backtrace dumped due to SIGSEGV! resuming signal");
+    };
+}
+
+/// 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
+}