Revert dbghelp 32-bit to known good version

src/backtrace/dbghelp32.rs

@@ -0,0 +1,257 @@
+//! Backtrace strategy for MSVC platforms.
+//!
+//! This module contains the ability to generate a backtrace on MSVC using one
+//! of two possible methods. The `StackWalkEx` function is primarily used if
+//! possible, but not all systems have that. Failing that the `StackWalk64`
+//! function is used instead. Note that `StackWalkEx` is favored because it
+//! handles debuginfo internally and returns inline frame information.
+//!
+//! Note that all dbghelp support is loaded dynamically, see `src/dbghelp.rs`
+//! for more information about that.
+
+#![allow(bad_style)]
+
+use super::super::{dbghelp, windows::*};
+use core::ffi::c_void;
+use core::mem;
+
+#[derive(Clone, Copy)]
+pub enum StackFrame {
+    New(STACKFRAME_EX),
+    Old(STACKFRAME64),
+}
+
+#[derive(Clone, Copy)]
+pub struct Frame {
+    pub(crate) stack_frame: StackFrame,
+    base_address: *mut c_void,
+}
+
+// we're just sending around raw pointers and reading them, never interpreting
+// them so this should be safe to both send and share across threads.
+unsafe impl Send for Frame {}
+unsafe impl Sync for Frame {}
+
+impl Frame {
+    pub fn ip(&self) -> *mut c_void {
+        self.addr_pc().Offset as *mut _
+    }
+
+    pub fn sp(&self) -> *mut c_void {
+        self.addr_stack().Offset as *mut _
+    }
+
+    pub fn symbol_address(&self) -> *mut c_void {
+        self.ip()
+    }
+
+    pub fn module_base_address(&self) -> Option<*mut c_void> {
+        Some(self.base_address)
+    }
+
+    fn addr_pc(&self) -> &ADDRESS64 {
+        match self.stack_frame {
+            StackFrame::New(ref new) => &new.AddrPC,
+            StackFrame::Old(ref old) => &old.AddrPC,
+        }
+    }
+
+    fn addr_pc_mut(&mut self) -> &mut ADDRESS64 {
+        match self.stack_frame {
+            StackFrame::New(ref mut new) => &mut new.AddrPC,
+            StackFrame::Old(ref mut old) => &mut old.AddrPC,
+        }
+    }
+
+    fn addr_frame_mut(&mut self) -> &mut ADDRESS64 {
+        match self.stack_frame {
+            StackFrame::New(ref mut new) => &mut new.AddrFrame,
+            StackFrame::Old(ref mut old) => &mut old.AddrFrame,
+        }
+    }
+
+    fn addr_stack(&self) -> &ADDRESS64 {
+        match self.stack_frame {
+            StackFrame::New(ref new) => &new.AddrStack,
+            StackFrame::Old(ref old) => &old.AddrStack,
+        }
+    }
+
+    fn addr_stack_mut(&mut self) -> &mut ADDRESS64 {
+        match self.stack_frame {
+            StackFrame::New(ref mut new) => &mut new.AddrStack,
+            StackFrame::Old(ref mut old) => &mut old.AddrStack,
+        }
+    }
+}
+
+#[repr(C, align(16))] // required by `CONTEXT`, is a FIXME in winapi right now
+struct MyContext(CONTEXT);
+
+#[inline(always)]
+pub unsafe fn trace(cb: &mut dyn FnMut(&super::Frame) -> bool) {
+    // Allocate necessary structures for doing the stack walk
+    let process = GetCurrentProcess();
+    let thread = GetCurrentThread();
+
+    let mut context = mem::zeroed::<MyContext>();
+    RtlCaptureContext(&mut context.0);
+
+    // Ensure this process's symbols are initialized
+    let dbghelp = match dbghelp::init() {
+        Ok(dbghelp) => dbghelp,
+        Err(()) => return, // oh well...
+    };
+
+    // On x86_64 and ARM64 we opt to not use the default `Sym*` functions from
+    // dbghelp for getting the function table and module base. Instead we use
+    // the `RtlLookupFunctionEntry` function in kernel32 which will account for
+    // JIT compiler frames as well. These should be equivalent, but using
+    // `Rtl*` allows us to backtrace through JIT frames.
+    //
+    // Note that `RtlLookupFunctionEntry` only works for in-process backtraces,
+    // but that's all we support anyway, so it all lines up well.
+    cfg_if::cfg_if! {
+        if #[cfg(target_pointer_width = "64")] {
+            use core::ptr;
+
+            unsafe extern "system" fn function_table_access(_process: HANDLE, addr: DWORD64) -> PVOID {
+                let mut base = 0;
+                RtlLookupFunctionEntry(addr, &mut base, ptr::null_mut()).cast()
+            }
+
+            unsafe extern "system" fn get_module_base(_process: HANDLE, addr: DWORD64) -> DWORD64 {
+                let mut base = 0;
+                RtlLookupFunctionEntry(addr, &mut base, ptr::null_mut());
+                base
+            }
+        } else {
+            let function_table_access = dbghelp.SymFunctionTableAccess64();
+            let get_module_base = dbghelp.SymGetModuleBase64();
+        }
+    }
+
+    let process_handle = GetCurrentProcess();
+
+    // Attempt to use `StackWalkEx` if we can, but fall back to `StackWalk64`
+    // since it's in theory supported on more systems.
+    match (*dbghelp.dbghelp()).StackWalkEx() {
+        Some(StackWalkEx) => {
+            let mut inner: STACKFRAME_EX = mem::zeroed();
+            inner.StackFrameSize = mem::size_of::<STACKFRAME_EX>() as DWORD;
+            let mut frame = super::Frame {
+                inner: Frame {
+                    stack_frame: StackFrame::New(inner),
+                    base_address: 0 as _,
+                },
+            };
+            let image = init_frame(&mut frame.inner, &context.0);
+            let frame_ptr = match &mut frame.inner.stack_frame {
+                StackFrame::New(ptr) => ptr as *mut STACKFRAME_EX,
+                _ => unreachable!(),
+            };
+
+            while StackWalkEx(
+                image as DWORD,
+                process,
+                thread,
+                frame_ptr,
+                &mut context.0 as *mut CONTEXT as *mut _,
+                None,
+                Some(function_table_access),
+                Some(get_module_base),
+                None,
+                0,
+            ) == TRUE
+            {
+                frame.inner.base_address = get_module_base(process_handle, frame.ip() as _) as _;
+
+                if !cb(&frame) {
+                    break;
+                }
+            }
+        }
+        None => {
+            let mut frame = super::Frame {
+                inner: Frame {
+                    stack_frame: StackFrame::Old(mem::zeroed()),
+                    base_address: 0 as _,
+                },
+            };
+            let image = init_frame(&mut frame.inner, &context.0);
+            let frame_ptr = match &mut frame.inner.stack_frame {
+                StackFrame::Old(ptr) => ptr as *mut STACKFRAME64,
+                _ => unreachable!(),
+            };
+
+            while dbghelp.StackWalk64()(
+                image as DWORD,
+                process,
+                thread,
+                frame_ptr,
+                &mut context.0 as *mut CONTEXT as *mut _,
+                None,
+                Some(function_table_access),
+                Some(get_module_base),
+                None,
+            ) == TRUE
+            {
+                frame.inner.base_address = get_module_base(process_handle, frame.ip() as _) as _;
+
+                if !cb(&frame) {
+                    break;
+                }
+            }
+        }
+    }
+}
+
+#[cfg(target_arch = "x86_64")]
+fn init_frame(frame: &mut Frame, ctx: &CONTEXT) -> WORD {
+    frame.addr_pc_mut().Offset = ctx.Rip as u64;
+    frame.addr_pc_mut().Mode = AddrModeFlat;
+    frame.addr_stack_mut().Offset = ctx.Rsp as u64;
+    frame.addr_stack_mut().Mode = AddrModeFlat;
+    frame.addr_frame_mut().Offset = ctx.Rbp as u64;
+    frame.addr_frame_mut().Mode = AddrModeFlat;
+
+    IMAGE_FILE_MACHINE_AMD64
+}
+
+#[cfg(target_arch = "x86")]
+fn init_frame(frame: &mut Frame, ctx: &CONTEXT) -> WORD {
+    frame.addr_pc_mut().Offset = ctx.Eip as u64;
+    frame.addr_pc_mut().Mode = AddrModeFlat;
+    frame.addr_stack_mut().Offset = ctx.Esp as u64;
+    frame.addr_stack_mut().Mode = AddrModeFlat;
+    frame.addr_frame_mut().Offset = ctx.Ebp as u64;
+    frame.addr_frame_mut().Mode = AddrModeFlat;
+
+    IMAGE_FILE_MACHINE_I386
+}
+
+#[cfg(target_arch = "aarch64")]
+fn init_frame(frame: &mut Frame, ctx: &CONTEXT) -> WORD {
+    frame.addr_pc_mut().Offset = ctx.Pc as u64;
+    frame.addr_pc_mut().Mode = AddrModeFlat;
+    frame.addr_stack_mut().Offset = ctx.Sp as u64;
+    frame.addr_stack_mut().Mode = AddrModeFlat;
+    unsafe {
+        frame.addr_frame_mut().Offset = ctx.u.s().Fp as u64;
+    }
+    frame.addr_frame_mut().Mode = AddrModeFlat;
+    IMAGE_FILE_MACHINE_ARM64
+}
+
+#[cfg(target_arch = "arm")]
+fn init_frame(frame: &mut Frame, ctx: &CONTEXT) -> WORD {
+    frame.addr_pc_mut().Offset = ctx.Pc as u64;
+    frame.addr_pc_mut().Mode = AddrModeFlat;
+    frame.addr_stack_mut().Offset = ctx.Sp as u64;
+    frame.addr_stack_mut().Mode = AddrModeFlat;
+    unsafe {
+        frame.addr_frame_mut().Offset = ctx.R11 as u64;
+    }
+    frame.addr_frame_mut().Mode = AddrModeFlat;
+    IMAGE_FILE_MACHINE_ARMNT
+}

src/backtrace/mod.rs

@@ -193,7 +193,15 @@ cfg_if::cfg_if! {
         use self::libunwind::trace as trace_imp;
         pub(crate) use self::libunwind::Frame as FrameImp;
     } else if #[cfg(all(windows, not(target_vendor = "uwp")))] {
-        mod dbghelp;
+        cfg_if::cfg_if! {
+            if #[cfg(any(target_arch = "x86_64", target_arch = "aarch64", target_arch = "arm64ec"))] {
+                mod dbghelp64;
+                use dbghelp64 as dbghelp;
+            } else if #[cfg(any(target_arch = "x86", target_arch = "arm"))] {
+                mod dbghelp32;
+                use dbghelp32 as dbghelp;
+            }
+        }
         use self::dbghelp::trace as trace_imp;
         pub(crate) use self::dbghelp::Frame as FrameImp;
     } else {