diff options
6 files changed, 74 insertions, 9 deletions
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs index 25b46241c52..172672a80fb 100644 --- a/compiler/rustc_session/src/session.rs +++ b/compiler/rustc_session/src/session.rs @@ -758,7 +758,8 @@ impl Session { // ELF x86-64 abi, but it can be disabled for some compilation units. // // Typically when we're compiling with `-C panic=abort` we don't need - // `uwtable` because we can't generate any exceptions! + // `uwtable` because we can't generate any exceptions! But note that + // some targets require unwind tables to generate backtraces. // Unwind tables are needed when compiling with `-C panic=unwind`, but // LLVM won't omit unwind tables unless the function is also marked as // `nounwind`, so users are allowed to disable `uwtable` emission. diff --git a/compiler/rustc_target/src/spec/base/android.rs b/compiler/rustc_target/src/spec/base/android.rs index 0426ea44c6a..df2757aaabf 100644 --- a/compiler/rustc_target/src/spec/base/android.rs +++ b/compiler/rustc_target/src/spec/base/android.rs @@ -8,10 +8,6 @@ pub(crate) fn opts() -> TargetOptions { base.tls_model = TlsModel::Emulated; base.has_thread_local = false; base.supported_sanitizers = SanitizerSet::ADDRESS; - // This is for backward compatibility, see https://github.com/rust-lang/rust/issues/49867 - // for context. (At that time, there was no `-C force-unwind-tables`, so the only solution - // was to always emit `uwtable`). - base.default_uwtable = true; base.crt_static_respected = true; base } diff --git a/compiler/rustc_target/src/spec/base/linux.rs b/compiler/rustc_target/src/spec/base/linux.rs index 9982c254eca..26e4590cf5e 100644 --- a/compiler/rustc_target/src/spec/base/linux.rs +++ b/compiler/rustc_target/src/spec/base/linux.rs @@ -12,6 +12,9 @@ pub(crate) fn opts() -> TargetOptions { relro_level: RelroLevel::Full, has_thread_local: true, crt_static_respected: true, + // We want backtraces to work by default and they rely on unwind tables + // (regardless of `-C panic` strategy). + default_uwtable: true, supported_split_debuginfo: Cow::Borrowed(&[ SplitDebuginfo::Packed, SplitDebuginfo::Unpacked, diff --git a/compiler/rustc_target/src/spec/targets/arm_unknown_linux_gnueabihf.rs b/compiler/rustc_target/src/spec/targets/arm_unknown_linux_gnueabihf.rs index a3f5389f0aa..0c711d5e71a 100644 --- a/compiler/rustc_target/src/spec/targets/arm_unknown_linux_gnueabihf.rs +++ b/compiler/rustc_target/src/spec/targets/arm_unknown_linux_gnueabihf.rs @@ -19,6 +19,11 @@ pub(crate) fn target() -> Target { max_atomic_width: Some(64), mcount: "\u{1}__gnu_mcount_nc".into(), llvm_mcount_intrinsic: Some("llvm.arm.gnu.eabi.mcount".into()), + // The default on linux is to have `default_uwtable=true`, but on + // this target we get an "`__aeabi_unwind_cpp_pr0` not defined" + // linker error, so set it to `true` here. + // FIXME(#146996): Remove this override once #146996 has been fixed. + default_uwtable: false, ..base::linux_gnu::opts() }, } diff --git a/tests/run-make/panic-abort-eh_frame/rmake.rs b/tests/run-make/panic-abort-eh_frame/rmake.rs index 23d95dc5774..2eccde62795 100644 --- a/tests/run-make/panic-abort-eh_frame/rmake.rs +++ b/tests/run-make/panic-abort-eh_frame/rmake.rs @@ -1,9 +1,11 @@ // An `.eh_frame` section in an object file is a symptom of an UnwindAction::Terminate // being inserted, useful for determining whether or not unwinding is necessary. -// This is useless when panics would NEVER unwind due to -C panic=abort. This section should -// therefore never appear in the emit file of a -C panic=abort compilation, and this test -// checks that this is respected. -// See https://github.com/rust-lang/rust/pull/112403 +// This is useless when panics would NEVER unwind due to -C panic=abort and when we don't need +// being able to generate backtraces (which depend on unwind tables on linux). This section should +// therefore never appear in the emit file of a -C panic=abort compilation +// with -C force-unwind-tables=no, and this test checks that this is respected. +// See https://github.com/rust-lang/rust/pull/112403 and +// https://github.com/rust-lang/rust/pull/143613. //@ only-linux // FIXME(Oneirical): the DW_CFA symbol appears on Windows-gnu, because uwtable @@ -19,6 +21,7 @@ fn main() { .panic("abort") .edition("2021") .arg("-Zvalidate-mir") + .arg("-Cforce-unwind-tables=no") .run(); llvm_objdump().arg("--dwarf=frames").input("foo.o").run().assert_stdout_not_contains("DW_CFA"); } diff --git a/tests/ui/panics/panic-abort-backtrace-without-debuginfo.rs b/tests/ui/panics/panic-abort-backtrace-without-debuginfo.rs new file mode 100644 index 00000000000..a29afd68523 --- /dev/null +++ b/tests/ui/panics/panic-abort-backtrace-without-debuginfo.rs @@ -0,0 +1,57 @@ +//! Test that with `-C panic=abort` the backtrace is not cut off by default +//! (i.e. without using `-C force-unwind-tables=yes`) by ensuring that our own +//! functions are in the backtrace. If we just check one function it might be +//! the last function, so make sure the backtrace can continue by checking for +//! two functions. Regression test for +//! <https://github.com/rust-lang/rust/issues/81902>. + +//@ run-pass +//@ needs-subprocess +// We want to test if unwind tables are emitted by default. We must make sure +// to disable debuginfo to test that, because enabling debuginfo also means that +// unwind tables are emitted, which prevents us from testing what we want. +// We also need to set opt-level=0 to avoid optimizing away our functions. +//@ compile-flags: -C panic=abort -C opt-level=0 -C debuginfo=0 +//@ no-prefer-dynamic +//@ ignore-apple +//@ ignore-arm-unknown-linux-gnueabihf FIXME(#146996) Try removing this once #146996 has been fixed. +//@ ignore-msvc Backtraces on Windows requires debuginfo which we can't use here + +static FN_1: &str = "this_function_must_be_in_the_backtrace"; +fn this_function_must_be_in_the_backtrace() { + and_this_function_too(); +} + +static FN_2: &str = "and_this_function_too"; +fn and_this_function_too() { + panic!("generate panic backtrace"); +} + +fn run_test() { + let output = std::process::Command::new(std::env::current_exe().unwrap()) + .arg("whatever") + .env("RUST_BACKTRACE", "full") + .output() + .unwrap(); + let backtrace = std::str::from_utf8(&output.stderr).unwrap(); + + fn assert(function_name: &str, backtrace: &str) { + assert!( + backtrace.contains(function_name), + "ERROR: no `{}` in stderr! actual stderr: {}", + function_name, + backtrace + ); + } + assert(FN_1, backtrace); + assert(FN_2, backtrace); +} + +fn main() { + let args: Vec<String> = std::env::args().collect(); + if args.len() == 1 { + run_test(); + } else { + this_function_must_be_in_the_backtrace(); + } +} |