Auto merge of #43635 - ids1024:backtrace-redox, r=alexcrichton

Make backtraces work on Redox, copying Unix implementation

The `backtrace/` directory here is the same as the Unix one, except for adding an implementation of `get_executable_filename`.

7 files changed, 197 insertions, 45 deletions

diff --git a/src/libbacktrace/config.sub b/src/libbacktrace/config.sub
index da6d1b6826a..40ea5dfe115 100644
--- a/src/libbacktrace/config.sub
+++ b/src/libbacktrace/config.sub
@@ -1,8 +1,8 @@
 #! /bin/sh
 # Configuration validation subroutine script.
-#   Copyright 1992-2016 Free Software Foundation, Inc.
+#   Copyright 1992-2017 Free Software Foundation, Inc.
 
-timestamp='2016-01-01'
+timestamp='2017-04-02'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -67,7 +67,7 @@ Report bugs and patches to <config-patches@gnu.org>."
 version="\
 GNU config.sub ($timestamp)
 
-Copyright 1992-2016 Free Software Foundation, Inc.
+Copyright 1992-2017 Free Software Foundation, Inc.
 
 This is free software; see the source for copying conditions.  There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
@@ -117,7 +117,7 @@ case $maybe_os in
   nto-qnx* | linux-gnu* | linux-android* | linux-dietlibc | linux-newlib* | \
   linux-musl* | linux-uclibc* | uclinux-uclibc* | uclinux-gnu* | kfreebsd*-gnu* | \
   knetbsd*-gnu* | netbsd*-gnu* | netbsd*-eabi* | \
-  kopensolaris*-gnu* | \
+  kopensolaris*-gnu* | cloudabi*-eabi* | \
   storm-chaos* | os2-emx* | rtmk-nova*)
     os=-$maybe_os
     basic_machine=`echo $1 | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\1/'`
@@ -263,7 +263,7 @@ case $basic_machine in
 	| fido | fr30 | frv | ft32 \
 	| h8300 | h8500 | hppa | hppa1.[01] | hppa2.0 | hppa2.0[nw] | hppa64 \
 	| hexagon \
-	| i370 | i860 | i960 | ia64 \
+	| i370 | i860 | i960 | ia16 | ia64 \
 	| ip2k | iq2000 \
 	| k1om \
 	| le32 | le64 \
@@ -301,6 +301,7 @@ case $basic_machine in
 	| open8 | or1k | or1knd | or32 \
 	| pdp10 | pdp11 | pj | pjl \
 	| powerpc | powerpc64 | powerpc64le | powerpcle \
+	| pru \
 	| pyramid \
 	| riscv32 | riscv64 \
 	| rl78 | rx \
@@ -314,6 +315,7 @@ case $basic_machine in
 	| ubicom32 \
 	| v850 | v850e | v850e1 | v850e2 | v850es | v850e2v3 \
 	| visium \
+	| wasm32 \
 	| we32k \
 	| x86 | xc16x | xstormy16 | xtensa \
 	| z8k | z80)
@@ -387,7 +389,7 @@ case $basic_machine in
 	| h8300-* | h8500-* \
 	| hppa-* | hppa1.[01]-* | hppa2.0-* | hppa2.0[nw]-* | hppa64-* \
 	| hexagon-* \
-	| i*86-* | i860-* | i960-* | ia64-* \
+	| i*86-* | i860-* | i960-* | ia16-* | ia64-* \
 	| ip2k-* | iq2000-* \
 	| k1om-* \
 	| le32-* | le64-* \
@@ -428,6 +430,7 @@ case $basic_machine in
 	| orion-* \
 	| pdp10-* | pdp11-* | pj-* | pjl-* | pn-* | power-* \
 	| powerpc-* | powerpc64-* | powerpc64le-* | powerpcle-* \
+	| pru-* \
 	| pyramid-* \
 	| riscv32-* | riscv64-* \
 	| rl78-* | romp-* | rs6000-* | rx-* \
@@ -444,6 +447,7 @@ case $basic_machine in
 	| v850-* | v850e-* | v850e1-* | v850es-* | v850e2-* | v850e2v3-* \
 	| vax-* \
 	| visium-* \
+	| wasm32-* \
 	| we32k-* \
 	| x86-* | x86_64-* | xc16x-* | xps100-* \
 	| xstormy16-* | xtensa*-* \
@@ -643,6 +647,14 @@ case $basic_machine in
 		basic_machine=m68k-bull
 		os=-sysv3
 		;;
+	e500v[12])
+		basic_machine=powerpc-unknown
+		os=$os"spe"
+		;;
+	e500v[12]-*)
+		basic_machine=powerpc-`echo $basic_machine | sed 's/^[^-]*-//'`
+		os=$os"spe"
+		;;
 	ebmon29k)
 		basic_machine=a29k-amd
 		os=-ebmon
@@ -938,6 +950,9 @@ case $basic_machine in
 	nsr-tandem)
 		basic_machine=nsr-tandem
 		;;
+	nsx-tandem)
+		basic_machine=nsx-tandem
+		;;
 	op50n-* | op60c-*)
 		basic_machine=hppa1.1-oki
 		os=-proelf
@@ -1022,7 +1037,7 @@ case $basic_machine in
 	ppc-* | ppcbe-*)
 		basic_machine=powerpc-`echo $basic_machine | sed 's/^[^-]*-//'`
 		;;
-	ppcle | powerpclittle | ppc-le | powerpc-little)
+	ppcle | powerpclittle)
 		basic_machine=powerpcle-unknown
 		;;
 	ppcle-* | powerpclittle-*)
@@ -1032,7 +1047,7 @@ case $basic_machine in
 		;;
 	ppc64-*) basic_machine=powerpc64-`echo $basic_machine | sed 's/^[^-]*-//'`
 		;;
-	ppc64le | powerpc64little | ppc64-le | powerpc64-little)
+	ppc64le | powerpc64little)
 		basic_machine=powerpc64le-unknown
 		;;
 	ppc64le-* | powerpc64little-*)
@@ -1233,6 +1248,9 @@ case $basic_machine in
 		basic_machine=a29k-wrs
 		os=-vxworks
 		;;
+	wasm32)
+		basic_machine=wasm32-unknown
+		;;
 	w65*)
 		basic_machine=w65-wdc
 		os=-none
@@ -1382,14 +1400,14 @@ case $os in
 	      | -nindy* | -vxsim* | -vxworks* | -ebmon* | -hms* | -mvs* \
 	      | -clix* | -riscos* | -uniplus* | -iris* | -rtu* | -xenix* \
 	      | -hiux* | -386bsd* | -knetbsd* | -mirbsd* | -netbsd* \
-	      | -bitrig* | -openbsd* | -solidbsd* \
+	      | -bitrig* | -openbsd* | -solidbsd* | -libertybsd* \
 	      | -ekkobsd* | -kfreebsd* | -freebsd* | -riscix* | -lynxos* \
 	      | -bosx* | -nextstep* | -cxux* | -aout* | -elf* | -oabi* \
 	      | -ptx* | -coff* | -ecoff* | -winnt* | -domain* | -vsta* \
 	      | -udi* | -eabi* | -lites* | -ieee* | -go32* | -aux* \
-	      | -chorusos* | -chorusrdb* | -cegcc* \
+	      | -chorusos* | -chorusrdb* | -cegcc* | -glidix* \
 	      | -cygwin* | -msys* | -pe* | -psos* | -moss* | -proelf* | -rtems* \
-	      | -mingw32* | -mingw64* | -linux-gnu* | -linux-android* \
+	      | -midipix* | -mingw32* | -mingw64* | -linux-gnu* | -linux-android* \
 	      | -linux-newlib* | -linux-musl* | -linux-uclibc* \
 	      | -uxpv* | -beos* | -mpeix* | -udk* | -moxiebox* \
 	      | -interix* | -uwin* | -mks* | -rhapsody* | -darwin* | -opened* \
@@ -1399,7 +1417,7 @@ case $os in
 	      | -morphos* | -superux* | -rtmk* | -rtmk-nova* | -windiss* \
 	      | -powermax* | -dnix* | -nx6 | -nx7 | -sei* | -dragonfly* \
 	      | -skyos* | -haiku* | -rdos* | -toppers* | -drops* | -es* \
-	      | -onefs* | -tirtos*)
+	      | -onefs* | -tirtos* | -phoenix* | -fuchsia* | -redox*)
 	# Remember, each alternative MUST END IN *, to match a version number.
 		;;
 	-qnx*)
@@ -1531,6 +1549,8 @@ case $os in
 		;;
 	-nacl*)
 		;;
+	-ios)
+		;;
 	-none)
 		;;
 	*)
@@ -1626,6 +1646,9 @@ case $basic_machine in
 	sparc-* | *-sun)
 		os=-sunos4.1.1
 		;;
+	pru-*)
+		os=-elf
+		;;
 	*-be)
 		os=-beos
 		;;
diff --git a/src/libstd/build.rs b/src/libstd/build.rs
index 0b5c2db171d..ab304f4c965 100644
--- a/src/libstd/build.rs
+++ b/src/libstd/build.rs
@@ -21,7 +21,7 @@ fn main() {
     let target = env::var("TARGET").expect("TARGET was not set");
     let host = env::var("HOST").expect("HOST was not set");
     if cfg!(feature = "backtrace") && !target.contains("apple") && !target.contains("msvc") &&
-        !target.contains("emscripten") && !target.contains("fuchsia") && !target.contains("redox") {
+        !target.contains("emscripten") && !target.contains("fuchsia") {
         let _ = build_libbacktrace(&host, &target);
     }
 
diff --git a/src/libstd/sys/redox/backtrace.rs b/src/libstd/sys/redox/backtrace.rs
deleted file mode 100644
index 6cafe3e69ba..00000000000
--- a/src/libstd/sys/redox/backtrace.rs
+++ /dev/null
@@ -1,32 +0,0 @@
-// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-use io;
-use sys_common::backtrace::Frame;
-
-pub use sys_common::gnu::libbacktrace::{foreach_symbol_fileline, resolve_symname};
-pub struct BacktraceContext;
-
-#[inline(never)]
-pub fn unwind_backtrace(_frames: &mut [Frame])
-    -> io::Result<(usize, BacktraceContext)>
-{
-    Ok((0, BacktraceContext))
-}
-
-pub mod gnu {
-    use io;
-    use fs;
-    use libc::c_char;
-
-    pub fn get_executable_filename() -> io::Result<(Vec<c_char>, fs::File)> {
-        Err(io::Error::new(io::ErrorKind::Other, "Not implemented"))
-    }
-}
diff --git a/src/libstd/sys/redox/backtrace/mod.rs b/src/libstd/sys/redox/backtrace/mod.rs
new file mode 100644
index 00000000000..40b957d847b
--- /dev/null
+++ b/src/libstd/sys/redox/backtrace/mod.rs
@@ -0,0 +1,42 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+/// See sys/unix/backtrace/mod.rs for an explanation of the method used here.
+
+pub use self::tracing::unwind_backtrace;
+pub use self::printing::{foreach_symbol_fileline, resolve_symname};
+
+// tracing impls:
+mod tracing;
+// symbol resolvers:
+mod printing;
+
+pub mod gnu {
+    use io;
+    use fs;
+    use libc::c_char;
+    use vec::Vec;
+    use ffi::OsStr;
+    use os::unix::ffi::OsStrExt;
+    use io::Read;
+
+    pub fn get_executable_filename() -> io::Result<(Vec<c_char>, fs::File)> {
+        let mut exefile = fs::File::open("sys:exe")?;
+        let mut exename = Vec::new();
+        exefile.read_to_end(&mut exename)?;
+        if exename.last() == Some(&b'\n') {
+            exename.pop();
+        }
+        let file = fs::File::open(OsStr::from_bytes(&exename))?;
+        Ok((exename.into_iter().map(|c| c as c_char).collect(), file))
+    }
+}
+
+pub struct BacktraceContext;
diff --git a/src/libstd/sys/redox/backtrace/printing.rs b/src/libstd/sys/redox/backtrace/printing.rs
new file mode 100644
index 00000000000..3e937dbe623
--- /dev/null
+++ b/src/libstd/sys/redox/backtrace/printing.rs
@@ -0,0 +1,11 @@
+// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub use sys_common::gnu::libbacktrace::{foreach_symbol_fileline, resolve_symname};
diff --git a/src/libstd/sys/redox/backtrace/tracing.rs b/src/libstd/sys/redox/backtrace/tracing.rs
new file mode 100644
index 00000000000..cfeabaddda9
--- /dev/null
+++ b/src/libstd/sys/redox/backtrace/tracing.rs
@@ -0,0 +1,106 @@
+// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use error::Error;
+use io;
+use libc;
+use sys::backtrace::BacktraceContext;
+use sys_common::backtrace::Frame;
+
+use unwind as uw;
+
+struct Context<'a> {
+    idx: usize,
+    frames: &'a mut [Frame],
+}
+
+#[derive(Debug)]
+struct UnwindError(uw::_Unwind_Reason_Code);
+
+impl Error for UnwindError {
+    fn description(&self) -> &'static str {
+        "unexpected return value while unwinding"
+    }
+}
+
+impl ::fmt::Display for UnwindError {
+    fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
+        write!(f, "{}: {:?}", self.description(), self.0)
+    }
+}
+
+#[inline(never)] // if we know this is a function call, we can skip it when
+                 // tracing
+pub fn unwind_backtrace(frames: &mut [Frame])
+    -> io::Result<(usize, BacktraceContext)>
+{
+    let mut cx = Context {
+        idx: 0,
+        frames: frames,
+    };
+    let result_unwind = unsafe {
+        uw::_Unwind_Backtrace(trace_fn,
+                              &mut cx as *mut Context
+                              as *mut libc::c_void)
+    };
+    // See libunwind:src/unwind/Backtrace.c for the return values.
+    // No, there is no doc.
+    match result_unwind {
+        // These return codes seem to be benign and need to be ignored for backtraces
+        // to show up properly on all tested platforms.
+        uw::_URC_END_OF_STACK | uw::_URC_FATAL_PHASE1_ERROR | uw::_URC_FAILURE => {
+            Ok((cx.idx, BacktraceContext))
+        }
+        _ => {
+            Err(io::Error::new(io::ErrorKind::Other,
+                               UnwindError(result_unwind)))
+        }
+    }
+}
+
+extern fn trace_fn(ctx: *mut uw::_Unwind_Context,
+                   arg: *mut libc::c_void) -> uw::_Unwind_Reason_Code {
+    let cx = unsafe { &mut *(arg as *mut Context) };
+    let mut ip_before_insn = 0;
+    let mut ip = unsafe {
+        uw::_Unwind_GetIPInfo(ctx, &mut ip_before_insn) as *mut libc::c_void
+    };
+    if !ip.is_null() && ip_before_insn == 0 {
+        // this is a non-signaling frame, so `ip` refers to the address
+        // after the calling instruction. account for that.
+        ip = (ip as usize - 1) as *mut _;
+    }
+
+    // dladdr() on osx gets whiny when we use FindEnclosingFunction, and
+    // it appears to work fine without it, so we only use
+    // FindEnclosingFunction on non-osx platforms. In doing so, we get a
+    // slightly more accurate stack trace in the process.
+    //
+    // This is often because panic involves the last instruction of a
+    // function being "call std::rt::begin_unwind", with no ret
+    // instructions after it. This means that the return instruction
+    // pointer points *outside* of the calling function, and by
+    // unwinding it we go back to the original function.
+    let symaddr = if cfg!(target_os = "macos") || cfg!(target_os = "ios") {
+        ip
+    } else {
+        unsafe { uw::_Unwind_FindEnclosingFunction(ip) }
+    };
+
+    if cx.idx < cx.frames.len() {
+        cx.frames[cx.idx] = Frame {
+            symbol_addr: symaddr,
+            exact_position: ip,
+        };
+        cx.idx += 1;
+    }
+
+    uw::_URC_NO_REASON
+}
diff --git a/src/libunwind/build.rs b/src/libunwind/build.rs
index be9aa6c5d40..cb8cb90e9ca 100644
--- a/src/libunwind/build.rs
+++ b/src/libunwind/build.rs
@@ -41,5 +41,7 @@ fn main() {
         println!("cargo:rustc-link-lib=unwind");
     } else if target.contains("haiku") {
         println!("cargo:rustc-link-lib=gcc_s");
+    } else if target.contains("redox") {
+        println!("cargo:rustc-link-lib=gcc");
     }
 }