Upgrade addr2line and properly handle split DWARF on Linux

.github/workflows/main.yml

@@ -229,7 +229,7 @@ jobs:
       with:
         submodules: true
     - name: Install Rust
-      run: rustup update 1.42.0 && rustup default 1.42.0
+      run: rustup update 1.55.0 && rustup default 1.55.0
     - run: cargo build
 
   miri:

Cargo.toml

@@ -37,7 +37,7 @@ rustc-serialize = { version = "0.3", optional = true }
 # Optionally demangle C++ frames' symbols in backtraces.
 cpp_demangle = { default-features = false, version = "0.4.0", optional = true, features = ["alloc"] }
 
-addr2line = { version = "0.19.0", default-features = false }
+addr2line = { version = "0.20.0", default-features = false }
 miniz_oxide = { version = "0.6.0", default-features = false }
 
 [dependencies.object]

crates/as-if-std/Cargo.toml

@@ -15,7 +15,7 @@ bench = false
 cfg-if = "1.0"
 rustc-demangle = "0.1.4"
 libc = { version = "0.2.45", default-features = false }
-addr2line = { version = "0.16.0", default-features = false, optional = true }
+addr2line = { version = "0.20.0", default-features = false, optional = true }
 miniz_oxide = { version = "0.4.0", default-features = false }
 
 [dependencies.object]

src/symbolize/gimli.rs

@@ -58,7 +58,7 @@ struct Mapping {
     // 'static lifetime is a lie to hack around lack of support for self-referential structs.
     cx: Context<'static>,
     _map: Mmap,
-    _stash: Stash,
+    stash: Stash,
 }
 
 enum Either<A, B> {
@@ -97,21 +97,23 @@ impl Mapping {
             // only borrow `map` and `stash` and we're preserving them below.
             cx: unsafe { core::mem::transmute::<Context<'_>, Context<'static>>(cx) },
             _map: data,
-            _stash: stash,
+            stash: stash,
         })
     }
 }
 
 struct Context<'a> {
     dwarf: addr2line::Context<EndianSlice<'a, Endian>>,
     object: Object<'a>,
+    package: Option<gimli::DwarfPackage<EndianSlice<'a, Endian>>>,
 }
 
 impl<'data> Context<'data> {
     fn new(
         stash: &'data Stash,
         object: Object<'data>,
         sup: Option<Object<'data>>,
+        dwp: Option<Object<'data>>,
     ) -> Option<Context<'data>> {
         let mut sections = gimli::Dwarf::load(|id| -> Result<_, ()> {
             let data = object.section(stash, id.name()).unwrap_or(&[]);
@@ -129,7 +131,46 @@ impl<'data> Context<'data> {
         }
         let dwarf = addr2line::Context::from_dwarf(sections).ok()?;
 
-        Some(Context { dwarf, object })
+        let mut package = None;
+        if let Some(dwp) = dwp {
+            package = Some(
+                gimli::DwarfPackage::load(
+                    |id| -> Result<_, gimli::Error> {
+                        let data = id
+                            .dwo_name()
+                            .and_then(|name| dwp.section(stash, name))
+                            .unwrap_or(&[]);
+                        Ok(EndianSlice::new(data, Endian))
+                    },
+                    EndianSlice::new(&[], Endian),
+                )
+                .ok()?,
+            );
+        }
+
+        Some(Context {
+            dwarf,
+            object,
+            package,
+        })
+    }
+
+    fn find_frames(
+        &'_ self,
+        stash: &'data Stash,
+        probe: u64,
+    ) -> gimli::Result<addr2line::FrameIter<'_, EndianSlice<'data, Endian>>> {
+        use addr2line::{LookupContinuation, LookupResult};
+
+        let mut l = self.dwarf.find_frames(probe);
+        loop {
+            let (load, continuation) = match l {
+                LookupResult::Output(output) => break output,
+                LookupResult::Load { load, continuation } => (load, continuation),
+            };
+
+            l = continuation.resume(handle_split_dwarf(self.package.as_ref(), stash, load));
+        }
     }
 }
 
@@ -142,18 +183,18 @@ fn mmap(path: &Path) -> Option<Mmap> {
 cfg_if::cfg_if! {
     if #[cfg(windows)] {
         mod coff;
-        use self::coff::Object;
+        use self::coff::{handle_split_dwarf, Object};
     } else if #[cfg(any(
         target_os = "macos",
         target_os = "ios",
         target_os = "tvos",
         target_os = "watchos",
     ))] {
         mod macho;
-        use self::macho::Object;
+        use self::macho::{handle_split_dwarf, Object};
     } else {
         mod elf;
-        use self::elf::Object;
+        use self::elf::{handle_split_dwarf, Object};
     }
 }
 
@@ -302,7 +343,7 @@ impl Cache {
             .next()
     }
 
-    fn mapping_for_lib<'a>(&'a mut self, lib: usize) -> Option<&'a mut Context<'a>> {
+    fn mapping_for_lib<'a>(&'a mut self, lib: usize) -> Option<(&'a mut Context<'a>, &'a Stash)> {
         let idx = self.mappings.iter().position(|(idx, _)| *idx == lib);
 
         // Invariant: after this conditional completes without early returning
@@ -328,10 +369,15 @@ impl Cache {
             self.mappings.insert(0, (lib, mapping));
         }
 
-        let cx: &'a mut Context<'static> = &mut self.mappings[0].1.cx;
+        let mapping = &mut self.mappings[0].1;
+        let cx: &'a mut Context<'static> = &mut mapping.cx;
+        let stash: &'a Stash = &mapping.stash;
         // don't leak the `'static` lifetime, make sure it's scoped to just
         // ourselves
-        Some(unsafe { mem::transmute::<&'a mut Context<'static>, &'a mut Context<'a>>(cx) })
+        Some((
+            unsafe { mem::transmute::<&'a mut Context<'static>, &'a mut Context<'a>>(cx) },
+            stash,
+        ))
     }
 }
 
@@ -353,12 +399,12 @@ pub unsafe fn resolve(what: ResolveWhat<'_>, cb: &mut dyn FnMut(&super::Symbol))
 
         // Finally, get a cached mapping or create a new mapping for this file, and
         // evaluate the DWARF info to find the file/line/name for this address.
-        let cx = match cache.mapping_for_lib(lib) {
-            Some(cx) => cx,
+        let (cx, stash) = match cache.mapping_for_lib(lib) {
+            Some((cx, stash)) => (cx, stash),
             None => return,
         };
         let mut any_frames = false;
-        if let Ok(mut frames) = cx.dwarf.find_frames(addr as u64) {
+        if let Ok(mut frames) = cx.find_frames(stash, addr as u64) {
             while let Ok(Some(frame)) = frames.next() {
                 any_frames = true;
                 let name = match frame.function {
@@ -374,7 +420,7 @@ pub unsafe fn resolve(what: ResolveWhat<'_>, cb: &mut dyn FnMut(&super::Symbol))
         }
         if !any_frames {
             if let Some((object_cx, object_addr)) = cx.object.search_object_map(addr as u64) {
-                if let Ok(mut frames) = object_cx.dwarf.find_frames(object_addr) {
+                if let Ok(mut frames) = object_cx.find_frames(stash, object_addr) {
                     while let Ok(Some(frame)) = frames.next() {
                         any_frames = true;
                         call(Symbol::Frame {

src/symbolize/gimli/coff.rs

@@ -1,4 +1,5 @@
-use super::{Context, Mapping, Path, Stash, Vec};
+use super::{gimli, Context, Endian, EndianSlice, Mapping, Path, Stash, Vec};
+use alloc::sync::Arc;
 use core::convert::TryFrom;
 use object::pe::{ImageDosHeader, ImageSymbol};
 use object::read::pe::{ImageNtHeaders, ImageOptionalHeader, SectionTable};
@@ -14,7 +15,7 @@ impl Mapping {
     pub fn new(path: &Path) -> Option<Mapping> {
         let map = super::mmap(path)?;
         Mapping::mk(map, |data, stash| {
-            Context::new(stash, Object::parse(data)?, None)
+            Context::new(stash, Object::parse(data)?, None, None)
         })
     }
 }
@@ -106,3 +107,11 @@ impl<'a> Object<'a> {
         None
     }
 }
+
+pub(super) fn handle_split_dwarf<'data>(
+    _package: Option<&gimli::DwarfPackage<EndianSlice<'data, Endian>>>,
+    _stash: &'data Stash,
+    _load: addr2line::SplitDwarfLoad<EndianSlice<'data, Endian>>,
+) -> Option<Arc<gimli::Dwarf<EndianSlice<'data, Endian>>>> {
+    None
+}

src/symbolize/gimli/elf.rs

@@ -3,7 +3,8 @@ use super::mystd::fs;
 use super::mystd::os::unix::ffi::{OsStrExt, OsStringExt};
 use super::mystd::path::{Path, PathBuf};
 use super::Either;
-use super::{Context, Mapping, Stash, Vec};
+use super::{gimli, Context, Endian, EndianSlice, Mapping, Stash, Vec};
+use alloc::sync::Arc;
 use core::convert::{TryFrom, TryInto};
 use core::str;
 use object::elf::{ELFCOMPRESS_ZLIB, ELF_NOTE_GNU, NT_GNU_BUILD_ID, SHF_COMPRESSED};
@@ -24,24 +25,26 @@ impl Mapping {
 
             // Try to locate an external debug file using the build ID.
             if let Some(path_debug) = object.build_id().and_then(locate_build_id) {
-                if let Some(mapping) = Mapping::new_debug(path_debug, None) {
+                if let Some(mapping) = Mapping::new_debug(path, path_debug, None) {
                     return Some(Either::A(mapping));
                 }
             }
 
             // Try to locate an external debug file using the GNU debug link section.
             if let Some((path_debug, crc)) = object.gnu_debuglink_path(path) {
-                if let Some(mapping) = Mapping::new_debug(path_debug, Some(crc)) {
+                if let Some(mapping) = Mapping::new_debug(path, path_debug, Some(crc)) {
                     return Some(Either::A(mapping));
                 }
             }
 
-            Context::new(stash, object, None).map(Either::B)
+            let dwp = Mapping::load_dwarf_package(path, stash);
+
+            Context::new(stash, object, None, dwp).map(Either::B)
         })
     }
 
     /// Load debuginfo from an external debug file.
-    fn new_debug(path: PathBuf, crc: Option<u32>) -> Option<Mapping> {
+    fn new_debug(original_path: &Path, path: PathBuf, crc: Option<u32>) -> Option<Mapping> {
         let map = super::mmap(&path)?;
         Mapping::mk(map, |map, stash| {
             let object = Object::parse(&map)?;
@@ -51,20 +54,45 @@ impl Mapping {
             }
 
             // Try to locate a supplementary object file.
+            let mut sup = None;
             if let Some((path_sup, build_id_sup)) = object.gnu_debugaltlink_path(&path) {
                 if let Some(map_sup) = super::mmap(&path_sup) {
-                    let map_sup = stash.set_mmap_aux(map_sup);
-                    if let Some(sup) = Object::parse(map_sup) {
-                        if sup.build_id() == Some(build_id_sup) {
-                            return Context::new(stash, object, Some(sup));
+                    let map_sup = stash.cache_mmap(map_sup);
+                    if let Some(sup_) = Object::parse(map_sup) {
+                        if sup_.build_id() == Some(build_id_sup) {
+                            sup = Some(sup_);
                         }
                     }
                 }
             }
 
-            Context::new(stash, object, None)
+            let dwp = Mapping::load_dwarf_package(original_path, stash);
+
+            Context::new(stash, object, sup, dwp)
         })
     }
+
+    /// Try to locate a DWARF package file.
+    fn load_dwarf_package<'data>(path: &Path, stash: &'data Stash) -> Option<Object<'data>> {
+        let mut path_dwp = path.to_path_buf();
+        let dwp_extension = path
+            .extension()
+            .map(|previous_extension| {
+                let mut previous_extension = previous_extension.to_os_string();
+                previous_extension.push(".dwp");
+                previous_extension
+            })
+            .unwrap_or_else(|| "dwp".into());
+        path_dwp.set_extension(dwp_extension);
+        if let Some(map_dwp) = super::mmap(&path_dwp) {
+            let map_dwp = stash.cache_mmap(map_dwp);
+            if let Some(dwp_) = Object::parse(map_dwp) {
+                return Some(dwp_);
+            }
+        }
+
+        None
+    }
 }
 
 struct ParsedSym {
@@ -421,3 +449,53 @@ fn locate_debugaltlink(path: &Path, filename: &[u8], build_id: &[u8]) -> Option<
 
     locate_build_id(build_id)
 }
+
+fn convert_path<R: gimli::Reader>(r: &R) -> Result<PathBuf, gimli::Error> {
+    let bytes = r.to_slice()?;
+    Ok(PathBuf::from(OsStr::from_bytes(&bytes)))
+}
+
+pub(super) fn handle_split_dwarf<'data>(
+    package: Option<&gimli::DwarfPackage<EndianSlice<'data, Endian>>>,
+    stash: &'data Stash,
+    load: addr2line::SplitDwarfLoad<EndianSlice<'data, Endian>>,
+) -> Option<Arc<gimli::Dwarf<EndianSlice<'data, Endian>>>> {
+    if let Some(dwp) = package.as_ref() {
+        if let Ok(Some(cu)) = dwp.find_cu(load.dwo_id, &load.parent) {
+            return Some(Arc::new(cu));
+        }
+    }
+
+    let mut path = PathBuf::new();
+    if let Some(p) = load.comp_dir.as_ref() {
+        if let Ok(p) = convert_path(p) {
+            path.push(p);
+        }
+    }
+
+    if let Some(p) = load.path.as_ref() {
+        if let Ok(p) = convert_path(p) {
+            path.push(p);
+        }
+    }
+
+    if let Some(map_dwo) = super::mmap(&path) {
+        let map_dwo = stash.cache_mmap(map_dwo);
+        if let Some(dwo) = Object::parse(map_dwo) {
+            return gimli::Dwarf::load(|id| -> Result<_, ()> {
+                let data = id
+                    .dwo_name()
+                    .and_then(|name| dwo.section(stash, name))
+                    .unwrap_or(&[]);
+                Ok(EndianSlice::new(data, Endian))
+            })
+            .ok()
+            .map(|mut dwo_dwarf| {
+                dwo_dwarf.make_dwo(&load.parent);
+                Arc::new(dwo_dwarf)
+            });
+        }
+    }
+
+    None
+}