Merge pull request #25 from philipc/gimli

Update gimli to 0.17.0

unwind/Cargo.toml

@@ -4,7 +4,7 @@ version = "0.1.0"
 authors = ["main() <[email protected]>"]
 
 [dependencies]
-gimli = "0.16.1"
+gimli = "0.17"
 libc = "0.2"
 fallible-iterator = "0.1"
 log = "0.4"
@@ -18,3 +18,4 @@ env_logger = "0.6"
 
 [features]
 nightly = []
+asm = ["nightly"]

unwind/build.rs

@@ -2,7 +2,7 @@ extern crate gcc;
 use std::env;
 
 fn main() {
-    match env::var("CARGO_FEATURE_NIGHTLY") {
+    match env::var("CARGO_FEATURE_ASM") {
         Err(env::VarError::NotPresent) => {
             gcc::Build::new()
                        .file("src/unwind_helper.c")

unwind/src/find_cfi/baremetal.rs

@@ -14,17 +14,20 @@ pub fn find_cfi_sections() -> Vec<EhRef> {
     unsafe {
         // Safety: None of those are actual accesses - we only get the address
         // of those values.
-        let text_start = &__text_start as *const _ as u64;
-        let text_end = &__text_end as *const _ as u64;
-        let cfi_start = &__ehframehdr_start as *const _ as u64;
-        let cfi_end = &__ehframehdr_end as *const _ as u64;
-        let ehframe_end = &__ehframe_end as *const _ as u64;
+        let text = AddrRange {
+            start: &__text_start as *const _ as u64,
+            end: &__text_end as *const _ as u64,
+        };
+        let eh_frame_hdr = AddrRange {
+            start: &__ehframehdr_start as *const _ as u64,
+            end: &__ehframehdr_end as *const _ as u64,
+        };
+        let eh_frame_end = &__ehframe_end as *const _ as u64;
 
         cfi.push(EhRef {
-            obj_base: 0,
-            text: AddrRange { start: text_start, end: text_end },
-            cfi: AddrRange { start: cfi_start, end: cfi_end },
-            ehframe_end,
+            text,
+            eh_frame_hdr,
+            eh_frame_end,
         });
     }
     trace!("CFI sections: {:?}", cfi);

unwind/src/find_cfi/ld.rs

@@ -58,18 +58,17 @@ extern "C" fn callback(info: *const DlPhdrInfo, size: usize, data: *mut c_void)
         let phdr = slice::from_raw_parts((*info).phdr, (*info).phnum as usize);
 
         if let Some(text) = phdr.iter().filter(|x| x.type_ == PT_LOAD && x.flags & PF_X != 0).next() {
-            if let Some(eh_frame) = phdr.iter().filter(|x| x.type_ == PT_GNU_EH_FRAME).next() {
+            if let Some(eh_frame_hdr) = phdr.iter().filter(|x| x.type_ == PT_GNU_EH_FRAME).next() {
                 let start_addr = (*info).addr + text.vaddr;
-                let cfi_start = (*info).addr + eh_frame.vaddr;
+                let eh_frame_hdr_start = (*info).addr + eh_frame_hdr.vaddr;
                 let max_vaddr = phdr.iter().filter(|x| x.type_ == PT_LOAD)
                     .fold(0, |vaddr, x| cmp::max(vaddr, x.vaddr + x.memsz));
                 // This is an upper bound, not the exact address.
-                let ehframe_end = (*info).addr + max_vaddr;
+                let eh_frame_end = (*info).addr + max_vaddr;
                 (*data).push(EhRef {
-                    obj_base: (*info).addr,
                     text: AddrRange { start: start_addr, end: start_addr + text.memsz },
-                    cfi: AddrRange { start: cfi_start, end: cfi_start + eh_frame.memsz },
-                    ehframe_end,
+                    eh_frame_hdr: AddrRange { start: eh_frame_hdr_start, end: eh_frame_hdr_start + eh_frame_hdr.memsz },
+                    eh_frame_end,
                 });
             }
         }

unwind/src/find_cfi/mod.rs

@@ -2,10 +2,9 @@ use range::AddrRange;
 
 #[derive(Debug)]
 pub struct EhRef {
-    pub obj_base: u64,
     pub text: AddrRange,
-    pub cfi: AddrRange,
-    pub ehframe_end: u64,
+    pub eh_frame_hdr: AddrRange,
+    pub eh_frame_end: u64,
 }
 
 #[cfg(unix)]

unwind/src/glue.rs

@@ -1,15 +1,16 @@
+use gimli::X86_64;
 use super::{UnwindPayload, StackFrames};
-use registers::{Registers, DwarfRegister};
+use registers::Registers;
 
 #[allow(improper_ctypes)] // trampoline just forwards the ptr
 extern "C" {
-    #[cfg(not(feature = "nightly"))]
+    #[cfg(not(feature = "asm"))]
     pub fn unwind_trampoline(payload: *mut UnwindPayload);
-    #[cfg(not(feature = "nightly"))]
+    #[cfg(not(feature = "asm"))]
     fn unwind_lander(regs: *const LandingRegisters);
 }
 
-#[cfg(feature = "nightly")]
+#[cfg(feature = "asm")]
 #[naked]
 pub unsafe extern fn unwind_trampoline(_payload: *mut UnwindPayload) {
     asm!("
@@ -33,7 +34,7 @@ pub unsafe extern fn unwind_trampoline(_payload: *mut UnwindPayload) {
     ::std::hint::unreachable_unchecked();
 }
 
-#[cfg(feature = "nightly")]
+#[cfg(feature = "asm")]
 #[naked]
 unsafe extern fn unwind_lander(_regs: *const LandingRegisters) {
     asm!("
@@ -96,14 +97,14 @@ pub unsafe extern "C" fn unwind_recorder(payload: *mut UnwindPayload, stack: u64
     let saved_regs = &*saved_regs;
 
     let mut registers = Registers::default();
-    registers[DwarfRegister::Rbx] = Some(saved_regs.rbx);
-    registers[DwarfRegister::Rbp] = Some(saved_regs.rbp);
-    registers[DwarfRegister::SP] = Some(stack + 8);
-    registers[DwarfRegister::R12] = Some(saved_regs.r12);
-    registers[DwarfRegister::R13] = Some(saved_regs.r13);
-    registers[DwarfRegister::R14] = Some(saved_regs.r14);
-    registers[DwarfRegister::R15] = Some(saved_regs.r15);
-    registers[DwarfRegister::IP] = Some(*(stack as *const u64));
+    registers[X86_64::RBX] = Some(saved_regs.rbx);
+    registers[X86_64::RBP] = Some(saved_regs.rbp);
+    registers[X86_64::RSP] = Some(stack + 8);
+    registers[X86_64::R12] = Some(saved_regs.r12);
+    registers[X86_64::R13] = Some(saved_regs.r13);
+    registers[X86_64::R14] = Some(saved_regs.r14);
+    registers[X86_64::R15] = Some(saved_regs.r15);
+    registers[X86_64::RA] = Some(*(stack as *const u64));
 
     let mut frames = StackFrames {
         unwinder: payload.unwinder,
@@ -116,24 +117,24 @@ pub unsafe extern "C" fn unwind_recorder(payload: *mut UnwindPayload, stack: u64
 
 pub unsafe fn land(regs: &Registers) {
     let mut lr = LandingRegisters {
-        rax: regs[DwarfRegister::Rax].unwrap_or(0),
-        rbx: regs[DwarfRegister::Rbx].unwrap_or(0),
-        rcx: regs[DwarfRegister::Rcx].unwrap_or(0),
-        rdx: regs[DwarfRegister::Rdx].unwrap_or(0),
-        rdi: regs[DwarfRegister::Rdi].unwrap_or(0),
-        rsi: regs[DwarfRegister::Rsi].unwrap_or(0),
-        rbp: regs[DwarfRegister::Rbp].unwrap_or(0),
-        r8:  regs[DwarfRegister::R8 ].unwrap_or(0),
-        r9:  regs[DwarfRegister::R9 ].unwrap_or(0),
-        r10: regs[DwarfRegister::R10].unwrap_or(0),
-        r11: regs[DwarfRegister::R11].unwrap_or(0),
-        r12: regs[DwarfRegister::R12].unwrap_or(0),
-        r13: regs[DwarfRegister::R13].unwrap_or(0),
-        r14: regs[DwarfRegister::R14].unwrap_or(0),
-        r15: regs[DwarfRegister::R15].unwrap_or(0),
-        rsp: regs[DwarfRegister::SP].unwrap(),
+        rax: regs[X86_64::RAX].unwrap_or(0),
+        rbx: regs[X86_64::RBX].unwrap_or(0),
+        rcx: regs[X86_64::RCX].unwrap_or(0),
+        rdx: regs[X86_64::RDX].unwrap_or(0),
+        rdi: regs[X86_64::RDI].unwrap_or(0),
+        rsi: regs[X86_64::RSI].unwrap_or(0),
+        rbp: regs[X86_64::RBP].unwrap_or(0),
+        r8:  regs[X86_64::R8 ].unwrap_or(0),
+        r9:  regs[X86_64::R9 ].unwrap_or(0),
+        r10: regs[X86_64::R10].unwrap_or(0),
+        r11: regs[X86_64::R11].unwrap_or(0),
+        r12: regs[X86_64::R12].unwrap_or(0),
+        r13: regs[X86_64::R13].unwrap_or(0),
+        r14: regs[X86_64::R14].unwrap_or(0),
+        r15: regs[X86_64::R15].unwrap_or(0),
+        rsp: regs[X86_64::RSP].unwrap(),
     };
     lr.rsp -= 8;
-    *(lr.rsp as *mut u64) = regs[DwarfRegister::IP].unwrap();
+    *(lr.rsp as *mut u64) = regs[X86_64::RA].unwrap();
     unwind_lander(&lr);
 }

unwind/src/lib.rs

@@ -1,19 +1,20 @@
-#![cfg_attr(feature = "nightly", feature(asm, naked_functions))]
+#![cfg_attr(feature = "nightly", feature(unwind_attributes))]
+#![cfg_attr(feature = "asm", feature(asm, naked_functions))]
 
 extern crate gimli;
 extern crate libc;
 extern crate fallible_iterator;
 #[macro_use] extern crate log;
 
-use gimli::{UnwindSection, UnwindTable, UnwindTableRow, EhFrame, BaseAddresses, UninitializedUnwindContext, Pointer, Reader, EndianSlice, NativeEndian, CfaRule, RegisterRule, EhFrameHdr, ParsedEhFrameHdr};
+use gimli::{UnwindSection, UnwindTable, UnwindTableRow, EhFrame, BaseAddresses, UninitializedUnwindContext, Pointer, Reader, EndianSlice, NativeEndian, CfaRule, RegisterRule, EhFrameHdr, ParsedEhFrameHdr, X86_64};
 use fallible_iterator::FallibleIterator;
 
 mod registers;
 mod find_cfi;
 mod range;
 pub mod libunwind_shim;
 pub mod glue;
-use registers::{Registers, DwarfRegister};
+use registers::Registers;
 use find_cfi::EhRef;
 
 
@@ -28,7 +29,6 @@ pub struct StackFrame {
     personality: Option<u64>,
     lsda: Option<u64>,
     initial_address: u64,
-    pub object_base: u64, // FIXME hack, remove this
 }
 
 pub trait Unwinder: Default {
@@ -53,20 +53,23 @@ impl Default for DwarfUnwinder {
     fn default() -> DwarfUnwinder {
         let cfi = find_cfi::find_cfi_sections().into_iter().map(|er| {
             unsafe {
-                let bases = BaseAddresses::default().set_cfi(er.cfi.start);
+                // TODO: set_got()
+                let bases = BaseAddresses::default()
+                    .set_eh_frame_hdr(er.eh_frame_hdr.start)
+                    .set_text(er.text.start);
 
-                let eh_frame_hdr: &'static [u8] = std::slice::from_raw_parts(er.cfi.start as *const u8, er.cfi.len() as usize);
+                let eh_frame_hdr: &'static [u8] = std::slice::from_raw_parts(er.eh_frame_hdr.start as *const u8, er.eh_frame_hdr.len() as usize);
 
                 let eh_frame_hdr = EhFrameHdr::new(eh_frame_hdr, NativeEndian).parse(&bases, 8).unwrap();
 
-                let cfi_addr = deref_ptr(eh_frame_hdr.eh_frame_ptr());
-                let cfi_sz = er.ehframe_end.saturating_sub(cfi_addr);
+                let eh_frame_addr = deref_ptr(eh_frame_hdr.eh_frame_ptr());
+                let eh_frame_sz = er.eh_frame_end.saturating_sub(eh_frame_addr);
 
-                let eh_frame: &'static [u8] = std::slice::from_raw_parts(cfi_addr as *const u8, cfi_sz as usize);
-                trace!("cfi at {:p} sz {:x}", cfi_addr as *const u8, cfi_sz);
+                let eh_frame: &'static [u8] = std::slice::from_raw_parts(eh_frame_addr as *const u8, eh_frame_sz as usize);
+                trace!("eh_frame at {:p} sz {:x}", eh_frame_addr as *const u8, eh_frame_sz);
                 let eh_frame = EhFrame::new(eh_frame, NativeEndian);
 
-                let bases = bases.set_cfi(cfi_addr).set_data(er.cfi.start);
+                let bases = bases.set_eh_frame(eh_frame_addr);
 
                 ObjectRecord { er, eh_frame_hdr, eh_frame, bases }
             }
@@ -167,10 +170,10 @@ impl<'a> FallibleIterator for StackFrames<'a> {
 
         if let Some((row, cfa)) = self.state.take() {
             let mut newregs = registers.clone();
-            newregs[DwarfRegister::IP] = None;
+            newregs[X86_64::RA] = None;
             for &(reg, ref rule) in row.registers() {
-                trace!("rule {} {:?}", reg, rule);
-                assert!(reg != 7); // stack = cfa
+                trace!("rule {:?} {:?}", reg, rule);
+                assert!(reg != X86_64::RSP); // stack = cfa
                 newregs[reg] = match *rule {
                     RegisterRule::Undefined => unreachable!(), // registers[reg],
                     RegisterRule::SameValue => Some(registers[reg].unwrap()), // not sure why this exists
@@ -189,7 +192,7 @@ impl<'a> FallibleIterator for StackFrames<'a> {
         }
 
 
-        if let Some(mut caller) = registers[DwarfRegister::IP] {
+        if let Some(mut caller) = registers[X86_64::RA] {
             caller -= 1; // THIS IS NECESSARY
             debug!("caller is 0x{:x}", caller);
 
@@ -210,7 +213,6 @@ impl<'a> FallibleIterator for StackFrames<'a> {
             self.state = Some((row, cfa));
 
             Ok(Some(StackFrame {
-                object_base: rec.er.obj_base,
                 personality: personality.map(|x| unsafe { deref_ptr(x) }),
                 lsda: lsda.map(|x| unsafe { deref_ptr(x) }),
                 initial_address,

unwind/src/libunwind_shim.rs

@@ -2,8 +2,9 @@
 
 use libc::{c_void, c_int};
 use fallible_iterator::FallibleIterator;
+use gimli::X86_64;
 
-use registers::{Registers, DwarfRegister};
+use registers::Registers;
 use super::{DwarfUnwinder, Unwinder};
 
 #[repr(C)]
@@ -53,6 +54,8 @@ pub type _Unwind_Trace_Fn = extern "C" fn(ctx: *mut _Unwind_Context, arg: *mut c
                                           -> _Unwind_Reason_Code;
 type PersonalityRoutine = extern "C" fn(version: c_int, actions: c_int, class: u64, object: *mut _Unwind_Exception, context: *mut _Unwind_Context) -> _Unwind_Reason_Code;
 
+// FIXME: we skip over this function when unwinding, so we should ensure
+// it never needs any cleanup. Currently this is not true.
 #[no_mangle]
 pub unsafe extern "C" fn _Unwind_Resume(exception: *mut _Unwind_Exception) -> ! {
     DwarfUnwinder::default().trace(|frames| unwind_tracer(frames, exception));
@@ -87,12 +90,12 @@ pub unsafe extern "C" fn _Unwind_GetLanguageSpecificData(ctx: *mut _Unwind_Conte
 
 #[no_mangle]
 pub unsafe extern "C" fn _Unwind_SetGR(ctx: *mut _Unwind_Context, reg_index: c_int, value: _Unwind_Word) {
-    (*(*ctx).registers)[reg_index as u8] = Some(value as u64);
+    (*(*ctx).registers)[reg_index as u16] = Some(value as u64);
 }
 
 #[no_mangle]
 pub unsafe extern "C" fn _Unwind_SetIP(ctx: *mut _Unwind_Context, value: _Unwind_Word) {
-    (*(*ctx).registers)[DwarfRegister::IP] = Some(value as u64);
+    (*(*ctx).registers)[X86_64::RA] = Some(value as u64);
 }
 
 #[no_mangle]
@@ -107,6 +110,13 @@ pub unsafe extern "C" fn _Unwind_FindEnclosingFunction(pc: *mut c_void) -> *mut
     pc // FIXME: implement this
 }
 
+// FIXME: Set `unwind(allowed)` because we need to be able to unwind this function as
+// part of its operation. But this means any panics in this function are undefined
+// behaviour, and we don't currently ensure it doesn't panic.
+//
+// On stable (1.32), `unwind(allowed)` is the default, but this will change in 1.33, with
+// no stable way of setting `unwind(allowed)`, so this function will always abort in 1.33.
+#[cfg_attr(feature = "nightly", unwind(allowed))]
 #[no_mangle]
 pub unsafe extern "C" fn _Unwind_RaiseException(exception: *mut _Unwind_Exception) -> _Unwind_Reason_Code {
     (*exception).private_contptr = None;
@@ -118,7 +128,7 @@ unsafe fn unwind_tracer(frames: &mut ::StackFrames, exception: *mut _Unwind_Exce
     if let Some(contptr) = (*exception).private_contptr {
         loop {
             if let Some(frame) = frames.next().unwrap() {
-                if frames.registers()[DwarfRegister::SP].unwrap() == contptr {
+                if frames.registers()[X86_64::RSP].unwrap() == contptr {
                     break;
                 }
             } else {
@@ -134,12 +144,12 @@ unsafe fn unwind_tracer(frames: &mut ::StackFrames, exception: *mut _Unwind_Exce
 
             let mut ctx = _Unwind_Context {
                 lsda: frame.lsda.unwrap(),
-                ip: frames.registers()[DwarfRegister::IP].unwrap(),
+                ip: frames.registers()[X86_64::RA].unwrap(),
                 initial_address: frame.initial_address,
                 registers: frames.registers(),
             };
 
-            (*exception).private_contptr = frames.registers()[DwarfRegister::SP];
+            (*exception).private_contptr = frames.registers()[X86_64::RSP];
 
             // ABI specifies that phase 1 is optional, so we just run phase 2 (CLEANUP_PHASE)
             match personality(1, _Unwind_Action::_UA_CLEANUP_PHASE as c_int, (*exception).exception_class,
@@ -160,7 +170,7 @@ pub unsafe extern "C" fn _Unwind_Backtrace(trace: _Unwind_Trace_Fn,
         while let Some(frame) = frames.next().unwrap() {
             let mut ctx = _Unwind_Context {
                 lsda: frame.lsda.unwrap_or(0),
-                ip: frames.registers()[DwarfRegister::IP].unwrap(),
+                ip: frames.registers()[X86_64::RA].unwrap(),
                 initial_address: frame.initial_address,
                 registers: frames.registers(),
             };