1 files changed, 218 insertions, 0 deletions
diff --git a/library/backtrace/src/symbolize/dbghelp.rs b/library/backtrace/src/symbolize/dbghelp.rs
new file mode 100644
index 000000000..181dba731
--- /dev/null
+++ b/library/backtrace/src/symbolize/dbghelp.rs
@@ -0,0 +1,218 @@
+//! Symbolication strategy using `dbghelp.dll` on Windows, only used for MSVC
+//!
+//! This symbolication strategy, like with backtraces, uses dynamically loaded
+//! information from `dbghelp.dll`. (see `src/dbghelp.rs` for info about why
+//! it's dynamically loaded).
+//!
+//! This API selects its resolution strategy based on the frame provided or the
+//! information we have at hand. If a frame from `StackWalkEx` is given to us
+//! then we use similar APIs to generate correct information about inlined
+//! functions. Otherwise if all we have is an address or an older stack frame
+//! from `StackWalk64` we use the older APIs for symbolication.
+//!
+//! There's a good deal of support in this module, but a good chunk of it is
+//! converting back and forth between Windows types and Rust types. For example
+//! symbols come to us as wide strings which we then convert to utf-8 strings if
+//! we can.
+
+#![allow(bad_style)]
+
+use super::super::{backtrace::StackFrame, dbghelp, windows::*};
+use super::{BytesOrWideString, ResolveWhat, SymbolName};
+use core::char;
+use core::ffi::c_void;
+use core::marker;
+use core::mem;
+use core::slice;
+
+// Store an OsString on std so we can provide the symbol name and filename.
+pub struct Symbol<'a> {
+    name: *const [u8],
+    addr: *mut c_void,
+    line: Option<u32>,
+    filename: Option<*const [u16]>,
+    #[cfg(feature = "std")]
+    _filename_cache: Option<::std::ffi::OsString>,
+    #[cfg(not(feature = "std"))]
+    _filename_cache: (),
+    _marker: marker::PhantomData<&'a i32>,
+}
+
+impl Symbol<'_> {
+    pub fn name(&self) -> Option<SymbolName<'_>> {
+        Some(SymbolName::new(unsafe { &*self.name }))
+    }
+
+    pub fn addr(&self) -> Option<*mut c_void> {
+        Some(self.addr as *mut _)
+    }
+
+    pub fn filename_raw(&self) -> Option<BytesOrWideString<'_>> {
+        self.filename
+            .map(|slice| unsafe { BytesOrWideString::Wide(&*slice) })
+    }
+
+    pub fn colno(&self) -> Option<u32> {
+        None
+    }
+
+    pub fn lineno(&self) -> Option<u32> {
+        self.line
+    }
+
+    #[cfg(feature = "std")]
+    pub fn filename(&self) -> Option<&::std::path::Path> {
+        use std::path::Path;
+
+        self._filename_cache.as_ref().map(Path::new)
+    }
+}
+
+#[repr(C, align(8))]
+struct Aligned8<T>(T);
+
+pub unsafe fn resolve(what: ResolveWhat<'_>, cb: &mut dyn FnMut(&super::Symbol)) {
+    // Ensure this process's symbols are initialized
+    let dbghelp = match dbghelp::init() {
+        Ok(dbghelp) => dbghelp,
+        Err(()) => return, // oh well...
+    };
+
+    match what {
+        ResolveWhat::Address(_) => resolve_without_inline(&dbghelp, what.address_or_ip(), cb),
+        ResolveWhat::Frame(frame) => match &frame.inner.stack_frame {
+            StackFrame::New(frame) => resolve_with_inline(&dbghelp, frame, cb),
+            StackFrame::Old(_) => resolve_without_inline(&dbghelp, frame.ip(), cb),
+        },
+    }
+}
+
+unsafe fn resolve_with_inline(
+    dbghelp: &dbghelp::Init,
+    frame: &STACKFRAME_EX,
+    cb: &mut dyn FnMut(&super::Symbol),
+) {
+    do_resolve(
+        |info| {
+            dbghelp.SymFromInlineContextW()(
+                GetCurrentProcess(),
+                super::adjust_ip(frame.AddrPC.Offset as *mut _) as u64,
+                frame.InlineFrameContext,
+                &mut 0,
+                info,
+            )
+        },
+        |line| {
+            dbghelp.SymGetLineFromInlineContextW()(
+                GetCurrentProcess(),
+                super::adjust_ip(frame.AddrPC.Offset as *mut _) as u64,
+                frame.InlineFrameContext,
+                0,
+                &mut 0,
+                line,
+            )
+        },
+        cb,
+    )
+}
+
+unsafe fn resolve_without_inline(
+    dbghelp: &dbghelp::Init,
+    addr: *mut c_void,
+    cb: &mut dyn FnMut(&super::Symbol),
+) {
+    do_resolve(
+        |info| dbghelp.SymFromAddrW()(GetCurrentProcess(), addr as DWORD64, &mut 0, info),
+        |line| dbghelp.SymGetLineFromAddrW64()(GetCurrentProcess(), addr as DWORD64, &mut 0, line),
+        cb,
+    )
+}
+
+unsafe fn do_resolve(
+    sym_from_addr: impl FnOnce(*mut SYMBOL_INFOW) -> BOOL,
+    get_line_from_addr: impl FnOnce(&mut IMAGEHLP_LINEW64) -> BOOL,
+    cb: &mut dyn FnMut(&super::Symbol),
+) {
+    const SIZE: usize = 2 * MAX_SYM_NAME + mem::size_of::<SYMBOL_INFOW>();
+    let mut data = Aligned8([0u8; SIZE]);
+    let data = &mut data.0;
+    let info = &mut *(data.as_mut_ptr() as *mut SYMBOL_INFOW);
+    info.MaxNameLen = MAX_SYM_NAME as ULONG;
+    // the struct size in C.  the value is different to
+    // `size_of::<SYMBOL_INFOW>() - MAX_SYM_NAME + 1` (== 81)
+    // due to struct alignment.
+    info.SizeOfStruct = 88;
+
+    if sym_from_addr(info) != TRUE {
+        return;
+    }
+
+    // If the symbol name is greater than MaxNameLen, SymFromAddrW will
+    // give a buffer of (MaxNameLen - 1) characters and set NameLen to
+    // the real value.
+    let name_len = ::core::cmp::min(info.NameLen as usize, info.MaxNameLen as usize - 1);
+    let name_ptr = info.Name.as_ptr() as *const u16;
+    let name = slice::from_raw_parts(name_ptr, name_len);
+
+    // Reencode the utf-16 symbol to utf-8 so we can use `SymbolName::new` like
+    // all other platforms
+    let mut name_len = 0;
+    let mut name_buffer = [0; 256];
+    {
+        let mut remaining = &mut name_buffer[..];
+        for c in char::decode_utf16(name.iter().cloned()) {
+            let c = c.unwrap_or(char::REPLACEMENT_CHARACTER);
+            let len = c.len_utf8();
+            if len < remaining.len() {
+                c.encode_utf8(remaining);
+                let tmp = remaining;
+                remaining = &mut tmp[len..];
+                name_len += len;
+            } else {
+                break;
+            }
+        }
+    }
+    let name = &name_buffer[..name_len] as *const [u8];
+
+    let mut line = mem::zeroed::<IMAGEHLP_LINEW64>();
+    line.SizeOfStruct = mem::size_of::<IMAGEHLP_LINEW64>() as DWORD;
+
+    let mut filename = None;
+    let mut lineno = None;
+    if get_line_from_addr(&mut line) == TRUE {
+        lineno = Some(line.LineNumber as u32);
+
+        let base = line.FileName;
+        let mut len = 0;
+        while *base.offset(len) != 0 {
+            len += 1;
+        }
+
+        let len = len as usize;
+
+        filename = Some(slice::from_raw_parts(base, len) as *const [u16]);
+    }
+
+    cb(&super::Symbol {
+        inner: Symbol {
+            name,
+            addr: info.Address as *mut _,
+            line: lineno,
+            filename,
+            _filename_cache: cache(filename),
+            _marker: marker::PhantomData,
+        },
+    })
+}
+
+#[cfg(feature = "std")]
+unsafe fn cache(filename: Option<*const [u16]>) -> Option<::std::ffi::OsString> {
+    use std::os::windows::ffi::OsStringExt;
+    filename.map(|f| ::std::ffi::OsString::from_wide(&*f))
+}
+
+#[cfg(not(feature = "std"))]
+unsafe fn cache(_filename: Option<*const [u16]>) {}
+
+pub unsafe fn clear_symbol_cache() {}