Cranelift in Unix working all the way with unwind info

lib/compiler-cranelift/src/compiler.rs

@@ -17,9 +17,7 @@ use cranelift_codegen::ir;
 use cranelift_codegen::print_errors::pretty_error;
 use cranelift_codegen::{binemit, isa, Context};
 #[cfg(feature = "unwind")]
-use gimli::write::{Address, EhFrame, EndianVec, FrameTable, Sections, Writer};
+use gimli::write::{Address, EhFrame, FrameTable};
-#[cfg(feature = "unwind")]
-use gimli::{RunTimeEndian, SectionId};
 use rayon::prelude::{IntoParallelRefIterator, ParallelIterator};
 use wasm_common::entity::{EntityRef, PrimaryMap};
 use wasm_common::{
@@ -189,6 +187,7 @@ impl Compiler for CraneliftCompiler {
             .into_iter()
             .collect::<PrimaryMap<LocalFunctionIndex, _>>();
 
+        let mut custom_sections = PrimaryMap::new();
         let mut eh_frame = EhFrame(WriterRelocate::default());
         dwarf_frametable
             .lock()
@@ -197,9 +196,6 @@ impl Compiler for CraneliftCompiler {
             .unwrap();
 
         let eh_frame_section = eh_frame.0.into_section();
-        println!("section: {:?}", eh_frame_section);
-
-        let mut custom_sections = PrimaryMap::new();
         custom_sections.push(eh_frame_section);
 
         let dwarf = Dwarf::new(SectionIndex::new(0));

lib/compiler-cranelift/src/dwarf.rs

@@ -1,4 +1,4 @@
-use gimli::write::{Address, Dwarf, EndianVec, FrameTable, Result, Sections, Writer};
+use gimli::write::{Address, EndianVec, Result, Writer};
 use gimli::{RunTimeEndian, SectionId};
 use wasm_common::entity::EntityRef;
 use wasm_common::LocalFunctionIndex;
@@ -84,7 +84,7 @@ impl Writer for WriterRelocate {
         }
     }
 
-    fn write_offset(&mut self, val: usize, section: SectionId, size: u8) -> Result<()> {
+    fn write_offset(&mut self, _val: usize, _section: SectionId, _size: u8) -> Result<()> {
         unimplemented!("write_offset not yet implemented");
         // let offset = self.len() as u32;
         // let target = section.name().to_string();
@@ -99,10 +99,10 @@ impl Writer for WriterRelocate {
 
     fn write_offset_at(
         &mut self,
-        offset: usize,
+        _offset: usize,
-        val: usize,
+        _val: usize,
-        section: SectionId,
+        _section: SectionId,
-        size: u8,
+        _size: u8,
     ) -> Result<()> {
         unimplemented!("write_offset_at not yet implemented");
         // let target = section.name().to_string();

lib/compiler/src/function.rs

@@ -77,12 +77,12 @@ pub type CustomSections = PrimaryMap<SectionIndex, CustomSection>;
 /// In the future this structure may also hold other information useful
 /// for debugging.
 #[cfg_attr(feature = "enable-serde", derive(Deserialize, Serialize))]
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq, Eq, Clone)]
 pub struct Dwarf {
     /// The section index in the [`Compilation`] that corresponds to the exception frames.
     /// More info:
     /// https://refspecs.linuxfoundation.org/LSB_3.0.0/LSB-PDA/LSB-PDA/ehframechpt.html
-    eh_frame: SectionIndex,
+    pub eh_frame: SectionIndex,
 }
 
 impl Dwarf {
@@ -179,6 +179,11 @@ impl Compilation {
             .map(|(_, section)| section.relocations.clone())
             .collect::<PrimaryMap<SectionIndex, _>>()
     }
+
+    /// Returns the Dwarf info.
+    pub fn get_dwarf(&self) -> Option<Dwarf> {
+        self.dwarf.clone()
+    }
 }
 
 impl<'a> IntoIterator for &'a Compilation {

lib/engine-jit/src/artifact.rs

@@ -118,6 +118,7 @@ impl JITArtifact {
             dynamic_function_trampolines,
             custom_sections: compilation.get_custom_sections(),
             custom_section_relocations: compilation.get_custom_section_relocations(),
+            dwarf: compilation.get_dwarf(),
         };
         let serializable = SerializableModule {
             compilation: serializable_compilation,
@@ -191,8 +192,21 @@ impl JITArtifact {
                 .collect::<PrimaryMap<_, _>>()
         };
 
+        let eh_frame = match &serializable.compilation.dwarf {
+            Some(dwarf) => {
+                let eh_frame_section_size = serializable.compilation.custom_sections
+                    [dwarf.eh_frame]
+                    .bytes
+                    .len();
+                let eh_frame_section_pointer = custom_sections[dwarf.eh_frame];
+                Some(unsafe {
+                    std::slice::from_raw_parts(eh_frame_section_pointer, eh_frame_section_size)
+                })
+            }
+            None => None,
+        };
         // Make all code compiled thus far executable.
-        inner_jit.publish_compiled_code();
+        inner_jit.publish_compiled_code(eh_frame);
 
         let finished_functions = finished_functions.into_boxed_slice();
         let finished_dynamic_function_trampolines =

lib/engine-jit/src/code_memory.rs

@@ -2,7 +2,6 @@
 use crate::unwind::UnwindRegistry;
 use region;
 use std::mem::ManuallyDrop;
-use std::ptr;
 use std::{cmp, mem};
 use wasm_common::entity::PrimaryMap;
 use wasm_common::LocalFunctionIndex;
@@ -140,7 +139,7 @@ impl CodeMemory {
     }
 
     /// Make all allocated memory executable.
-    pub fn publish(&mut self) {
+    pub fn publish(&mut self, eh_frame: Option<&[u8]>) {
         self.push_current(0)
             .expect("failed to push current memory map");
 
@@ -150,7 +149,7 @@ impl CodeMemory {
         } in &mut self.entries[self.published..]
         {
             // Remove write access to the pages due to the relocation fixups.
-            r.publish()
+            r.publish(eh_frame)
                 .expect("failed to publish function unwind registry");
 
             if !m.is_empty() {

lib/engine-jit/src/engine.rs

@@ -248,8 +248,8 @@ impl JITEngineInner {
     }
 
     /// Make memory containing compiled code executable.
-    pub(crate) fn publish_compiled_code(&mut self) {
+    pub(crate) fn publish_compiled_code(&mut self, eh_frame: Option<&[u8]>) {
-        self.code_memory.publish();
+        self.code_memory.publish(eh_frame);
     }
 
     /// Shared signature registry.

lib/engine-jit/src/serialize.rs

@@ -5,7 +5,9 @@ use wasm_common::{
     Features, FunctionIndex, LocalFunctionIndex, MemoryIndex, OwnedDataInitializer, SignatureIndex,
     TableIndex,
 };
-use wasmer_compiler::{CustomSection, FunctionBody, JumpTableOffsets, Relocation, SectionIndex};
+use wasmer_compiler::{
+    CustomSection, Dwarf, FunctionBody, JumpTableOffsets, Relocation, SectionIndex,
+};
 use wasmer_engine::SerializableFunctionFrameInfo;
 use wasmer_runtime::ModuleInfo;
 use wasmer_runtime::{MemoryPlan, TablePlan};
@@ -24,6 +26,8 @@ pub struct SerializableCompilation {
     pub dynamic_function_trampolines: PrimaryMap<FunctionIndex, FunctionBody>,
     pub custom_sections: PrimaryMap<SectionIndex, CustomSection>,
     pub custom_section_relocations: PrimaryMap<SectionIndex, Vec<Relocation>>,
+    // The section corresponding to the Dwarf debug infos
+    pub dwarf: Option<Dwarf>,
 }
 
 /// Serializable struct that is able to serialize from and to

lib/engine-jit/src/unwind/dummy.rs

@@ -24,7 +24,7 @@ impl DummyUnwindRegistry {
     }
 
     /// Publishes all registered functions.
-    pub fn publish(&mut self) -> Result<(), String> {
+    pub fn publish(&mut self, eh_frame: Option<&[u8]>) -> Result<(), String> {
         // Do nothing
         Ok(())
     }

lib/engine-jit/src/unwind/mod.rs

@@ -2,15 +2,12 @@ cfg_if::cfg_if! {
     if #[cfg(all(windows, target_arch = "x86_64"))] {
         mod windows_x64;
         pub use self::windows_x64::*;
-    } else if #[cfg(all(windows, target_arch = "x86"))] {
+    } else if #[cfg(unix)] {
-        mod windows_x32;
+        mod systemv;
-        pub use self::windows_x32::*;
+        pub use self::systemv::*;
-    // } else if #[cfg(unix)] {
-    //     mod systemv;
-    //     pub use self::systemv::*;
     } else {
+        // Otherwise, we provide a dummy fallback without unwinding
         mod dummy;
         pub use self::dummy::DummyUnwindRegistry as UnwindRegistry;
-        // compile_error!("unsupported target platform for unwind");
     }
 }

lib/engine-jit/src/unwind/systemv.rs

@@ -3,9 +3,6 @@ use wasmer_compiler::CompiledFunctionUnwindInfo;
 
 /// Represents a registry of function unwind information for System V ABI.
 pub struct UnwindRegistry {
-    base_address: usize,
-    functions: Vec<gimli::write::FrameDescriptionEntry>,
-    frame_table: Vec<u8>,
     registrations: Vec<usize>,
     published: bool,
 }
@@ -18,35 +15,33 @@ extern "C" {
 
 impl UnwindRegistry {
     /// Creates a new unwind registry with the given base address.
-    pub fn new(base_address: usize) -> Self {
+    pub fn new(_base_address: usize) -> Self {
         Self {
-            base_address,
-            functions: Vec::new(),
-            frame_table: Vec::new(),
             registrations: Vec::new(),
             published: false,
         }
     }
 
     /// Registers a function given the start offset, length, and unwind information.
-    pub fn register(&mut self, _func_start: u32, _func_len: u32, _info: &CompiledFunctionUnwindInfo) -> Result<(), String> {
+    pub fn register(
-        // Do nothing
+        &mut self,
+        _func_start: u32,
+        _func_len: u32,
+        info: &CompiledFunctionUnwindInfo,
+    ) -> Result<(), String> {
+        match info {
+            CompiledFunctionUnwindInfo::Dwarf => {}
+            _ => return Err("unsupported unwind information".to_string()),
+        };
         Ok(())
     }
 
     /// Publishes all registered functions.
-    pub fn publish(&mut self, isa: &dyn TargetIsa) -> Result<()> {
+    pub fn publish(&mut self, eh_frame: Option<&[u8]>) -> Result<(), String> {
-        if self.published {
+        if let Some(eh_frame) = eh_frame {
-            bail!("unwind registry has already been published");
-        }
-
-        if self.functions.is_empty() {
-            self.published = true;
-            return Ok(());
-        }
-
             unsafe {
-            self.register_frames();
+                self.register_frames(eh_frame);
+            }
         }
 
         self.published = true;
@@ -54,13 +49,13 @@ impl UnwindRegistry {
         Ok(())
     }
 
-
+    #[allow(clippy::cast_ptr_alignment)]
-    unsafe fn register_frames(&mut self) {
+    unsafe fn register_frames(&mut self, eh_frame: &[u8]) {
         cfg_if::cfg_if! {
             if #[cfg(target_os = "macos")] {
                 // On macOS, `__register_frame` takes a pointer to a single FDE
-                let start = self.frame_table.as_ptr();
+                let start = eh_frame.as_ptr();
-                let end = start.add(self.frame_table.len());
+                let end = start.add(eh_frame.len());
                 let mut current = start;
 
                 // Walk all of the entries in the frame table and register them
@@ -78,7 +73,7 @@ impl UnwindRegistry {
                 }
             } else {
                 // On other platforms, `__register_frame` will walk the FDEs until an entry of length 0
-                let ptr = self.frame_table.as_ptr();
+                let ptr = eh_frame.as_ptr();
                 __register_frame(ptr);
                 self.registrations.push(ptr as usize);
             }

lib/engine-jit/src/unwind/windows_x64.rs

@@ -32,7 +32,10 @@ impl UnwindRegistry {
         }
 
         match info {
-            CompiledFunctionUnwindInfo::WindowsX64(_) => {
+            CompiledFunctionUnwindInfo::WindowsX64(_) => {}
+            _ => return Err("unsupported unwind information".to_string()),
+        };
+
         let mut entry = winnt::RUNTIME_FUNCTION::default();
 
         entry.BeginAddress = func_start;
@@ -48,12 +51,9 @@ impl UnwindRegistry {
 
         Ok(())
     }
-            _ => Err("unsupported unwind information".to_string()),
-        }
-    }
 
     /// Publishes all registered functions.
-    pub fn publish(&mut self) -> Result<(), String> {
+    pub fn publish(&mut self, _eh_frame: Option<&[u8]>) -> Result<(), String> {
         if self.published {
             return Err("unwind registry has already been published".to_string());
         }