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authormark <markm@cs.wisc.edu>2020-06-11 21:31:49 -0500
committermark <markm@cs.wisc.edu>2020-07-27 19:51:13 -0500
commit2c31b45ae878b821975c4ebd94cc1e49f6073fd0 (patch)
tree14f64e683e3f64dcbcfb8c2c7cb45ac7592e6e09 /src/libpanic_unwind/dwarf
parent9be8ffcb0206fc1558069a7b4766090df7877659 (diff)
downloadrust-2c31b45ae878b821975c4ebd94cc1e49f6073fd0.tar.gz
rust-2c31b45ae878b821975c4ebd94cc1e49f6073fd0.zip
mv std libs to library/
Diffstat (limited to 'src/libpanic_unwind/dwarf')
-rw-r--r--src/libpanic_unwind/dwarf/eh.rs200
-rw-r--r--src/libpanic_unwind/dwarf/mod.rs73
-rw-r--r--src/libpanic_unwind/dwarf/tests.rs19
3 files changed, 0 insertions, 292 deletions
diff --git a/src/libpanic_unwind/dwarf/eh.rs b/src/libpanic_unwind/dwarf/eh.rs
deleted file mode 100644
index 302478cfac8..00000000000
--- a/src/libpanic_unwind/dwarf/eh.rs
+++ /dev/null
@@ -1,200 +0,0 @@
-//! Parsing of GCC-style Language-Specific Data Area (LSDA)
-//! For details see:
-//!   http://refspecs.linuxfoundation.org/LSB_3.0.0/LSB-PDA/LSB-PDA/ehframechpt.html
-//!   http://mentorembedded.github.io/cxx-abi/exceptions.pdf
-//!   http://www.airs.com/blog/archives/460
-//!   http://www.airs.com/blog/archives/464
-//!
-//! A reference implementation may be found in the GCC source tree
-//! (`<root>/libgcc/unwind-c.c` as of this writing).
-
-#![allow(non_upper_case_globals)]
-#![allow(unused)]
-
-use crate::dwarf::DwarfReader;
-use core::mem;
-
-pub const DW_EH_PE_omit: u8 = 0xFF;
-pub const DW_EH_PE_absptr: u8 = 0x00;
-
-pub const DW_EH_PE_uleb128: u8 = 0x01;
-pub const DW_EH_PE_udata2: u8 = 0x02;
-pub const DW_EH_PE_udata4: u8 = 0x03;
-pub const DW_EH_PE_udata8: u8 = 0x04;
-pub const DW_EH_PE_sleb128: u8 = 0x09;
-pub const DW_EH_PE_sdata2: u8 = 0x0A;
-pub const DW_EH_PE_sdata4: u8 = 0x0B;
-pub const DW_EH_PE_sdata8: u8 = 0x0C;
-
-pub const DW_EH_PE_pcrel: u8 = 0x10;
-pub const DW_EH_PE_textrel: u8 = 0x20;
-pub const DW_EH_PE_datarel: u8 = 0x30;
-pub const DW_EH_PE_funcrel: u8 = 0x40;
-pub const DW_EH_PE_aligned: u8 = 0x50;
-
-pub const DW_EH_PE_indirect: u8 = 0x80;
-
-#[derive(Copy, Clone)]
-pub struct EHContext<'a> {
-    pub ip: usize,                             // Current instruction pointer
-    pub func_start: usize,                     // Address of the current function
-    pub get_text_start: &'a dyn Fn() -> usize, // Get address of the code section
-    pub get_data_start: &'a dyn Fn() -> usize, // Get address of the data section
-}
-
-pub enum EHAction {
-    None,
-    Cleanup(usize),
-    Catch(usize),
-    Terminate,
-}
-
-pub const USING_SJLJ_EXCEPTIONS: bool = cfg!(all(target_os = "ios", target_arch = "arm"));
-
-pub unsafe fn find_eh_action(
-    lsda: *const u8,
-    context: &EHContext<'_>,
-    foreign_exception: bool,
-) -> Result<EHAction, ()> {
-    if lsda.is_null() {
-        return Ok(EHAction::None);
-    }
-
-    let func_start = context.func_start;
-    let mut reader = DwarfReader::new(lsda);
-
-    let start_encoding = reader.read::<u8>();
-    // base address for landing pad offsets
-    let lpad_base = if start_encoding != DW_EH_PE_omit {
-        read_encoded_pointer(&mut reader, context, start_encoding)?
-    } else {
-        func_start
-    };
-
-    let ttype_encoding = reader.read::<u8>();
-    if ttype_encoding != DW_EH_PE_omit {
-        // Rust doesn't analyze exception types, so we don't care about the type table
-        reader.read_uleb128();
-    }
-
-    let call_site_encoding = reader.read::<u8>();
-    let call_site_table_length = reader.read_uleb128();
-    let action_table = reader.ptr.offset(call_site_table_length as isize);
-    let ip = context.ip;
-
-    if !USING_SJLJ_EXCEPTIONS {
-        while reader.ptr < action_table {
-            let cs_start = read_encoded_pointer(&mut reader, context, call_site_encoding)?;
-            let cs_len = read_encoded_pointer(&mut reader, context, call_site_encoding)?;
-            let cs_lpad = read_encoded_pointer(&mut reader, context, call_site_encoding)?;
-            let cs_action = reader.read_uleb128();
-            // Callsite table is sorted by cs_start, so if we've passed the ip, we
-            // may stop searching.
-            if ip < func_start + cs_start {
-                break;
-            }
-            if ip < func_start + cs_start + cs_len {
-                if cs_lpad == 0 {
-                    return Ok(EHAction::None);
-                } else {
-                    let lpad = lpad_base + cs_lpad;
-                    return Ok(interpret_cs_action(cs_action, lpad, foreign_exception));
-                }
-            }
-        }
-        // Ip is not present in the table.  This should not happen... but it does: issue #35011.
-        // So rather than returning EHAction::Terminate, we do this.
-        Ok(EHAction::None)
-    } else {
-        // SjLj version:
-        // The "IP" is an index into the call-site table, with two exceptions:
-        // -1 means 'no-action', and 0 means 'terminate'.
-        match ip as isize {
-            -1 => return Ok(EHAction::None),
-            0 => return Ok(EHAction::Terminate),
-            _ => (),
-        }
-        let mut idx = ip;
-        loop {
-            let cs_lpad = reader.read_uleb128();
-            let cs_action = reader.read_uleb128();
-            idx -= 1;
-            if idx == 0 {
-                // Can never have null landing pad for sjlj -- that would have
-                // been indicated by a -1 call site index.
-                let lpad = (cs_lpad + 1) as usize;
-                return Ok(interpret_cs_action(cs_action, lpad, foreign_exception));
-            }
-        }
-    }
-}
-
-fn interpret_cs_action(cs_action: u64, lpad: usize, foreign_exception: bool) -> EHAction {
-    if cs_action == 0 {
-        // If cs_action is 0 then this is a cleanup (Drop::drop). We run these
-        // for both Rust panics and foreign exceptions.
-        EHAction::Cleanup(lpad)
-    } else if foreign_exception {
-        // catch_unwind should not catch foreign exceptions, only Rust panics.
-        // Instead just continue unwinding.
-        EHAction::None
-    } else {
-        // Stop unwinding Rust panics at catch_unwind.
-        EHAction::Catch(lpad)
-    }
-}
-
-#[inline]
-fn round_up(unrounded: usize, align: usize) -> Result<usize, ()> {
-    if align.is_power_of_two() { Ok((unrounded + align - 1) & !(align - 1)) } else { Err(()) }
-}
-
-unsafe fn read_encoded_pointer(
-    reader: &mut DwarfReader,
-    context: &EHContext<'_>,
-    encoding: u8,
-) -> Result<usize, ()> {
-    if encoding == DW_EH_PE_omit {
-        return Err(());
-    }
-
-    // DW_EH_PE_aligned implies it's an absolute pointer value
-    if encoding == DW_EH_PE_aligned {
-        reader.ptr = round_up(reader.ptr as usize, mem::size_of::<usize>())? as *const u8;
-        return Ok(reader.read::<usize>());
-    }
-
-    let mut result = match encoding & 0x0F {
-        DW_EH_PE_absptr => reader.read::<usize>(),
-        DW_EH_PE_uleb128 => reader.read_uleb128() as usize,
-        DW_EH_PE_udata2 => reader.read::<u16>() as usize,
-        DW_EH_PE_udata4 => reader.read::<u32>() as usize,
-        DW_EH_PE_udata8 => reader.read::<u64>() as usize,
-        DW_EH_PE_sleb128 => reader.read_sleb128() as usize,
-        DW_EH_PE_sdata2 => reader.read::<i16>() as usize,
-        DW_EH_PE_sdata4 => reader.read::<i32>() as usize,
-        DW_EH_PE_sdata8 => reader.read::<i64>() as usize,
-        _ => return Err(()),
-    };
-
-    result += match encoding & 0x70 {
-        DW_EH_PE_absptr => 0,
-        // relative to address of the encoded value, despite the name
-        DW_EH_PE_pcrel => reader.ptr as usize,
-        DW_EH_PE_funcrel => {
-            if context.func_start == 0 {
-                return Err(());
-            }
-            context.func_start
-        }
-        DW_EH_PE_textrel => (*context.get_text_start)(),
-        DW_EH_PE_datarel => (*context.get_data_start)(),
-        _ => return Err(()),
-    };
-
-    if encoding & DW_EH_PE_indirect != 0 {
-        result = *(result as *const usize);
-    }
-
-    Ok(result)
-}
diff --git a/src/libpanic_unwind/dwarf/mod.rs b/src/libpanic_unwind/dwarf/mod.rs
deleted file mode 100644
index 649bbce52a3..00000000000
--- a/src/libpanic_unwind/dwarf/mod.rs
+++ /dev/null
@@ -1,73 +0,0 @@
-//! Utilities for parsing DWARF-encoded data streams.
-//! See <http://www.dwarfstd.org>,
-//! DWARF-4 standard, Section 7 - "Data Representation"
-
-// This module is used only by x86_64-pc-windows-gnu for now, but we
-// are compiling it everywhere to avoid regressions.
-#![allow(unused)]
-
-#[cfg(test)]
-mod tests;
-
-pub mod eh;
-
-use core::mem;
-
-pub struct DwarfReader {
-    pub ptr: *const u8,
-}
-
-#[repr(C, packed)]
-struct Unaligned<T>(T);
-
-impl DwarfReader {
-    pub fn new(ptr: *const u8) -> DwarfReader {
-        DwarfReader { ptr }
-    }
-
-    // DWARF streams are packed, so e.g., a u32 would not necessarily be aligned
-    // on a 4-byte boundary. This may cause problems on platforms with strict
-    // alignment requirements. By wrapping data in a "packed" struct, we are
-    // telling the backend to generate "misalignment-safe" code.
-    pub unsafe fn read<T: Copy>(&mut self) -> T {
-        let Unaligned(result) = *(self.ptr as *const Unaligned<T>);
-        self.ptr = self.ptr.add(mem::size_of::<T>());
-        result
-    }
-
-    // ULEB128 and SLEB128 encodings are defined in Section 7.6 - "Variable
-    // Length Data".
-    pub unsafe fn read_uleb128(&mut self) -> u64 {
-        let mut shift: usize = 0;
-        let mut result: u64 = 0;
-        let mut byte: u8;
-        loop {
-            byte = self.read::<u8>();
-            result |= ((byte & 0x7F) as u64) << shift;
-            shift += 7;
-            if byte & 0x80 == 0 {
-                break;
-            }
-        }
-        result
-    }
-
-    pub unsafe fn read_sleb128(&mut self) -> i64 {
-        let mut shift: usize = 0;
-        let mut result: u64 = 0;
-        let mut byte: u8;
-        loop {
-            byte = self.read::<u8>();
-            result |= ((byte & 0x7F) as u64) << shift;
-            shift += 7;
-            if byte & 0x80 == 0 {
-                break;
-            }
-        }
-        // sign-extend
-        if shift < 8 * mem::size_of::<u64>() && (byte & 0x40) != 0 {
-            result |= (!0 as u64) << shift;
-        }
-        result as i64
-    }
-}
diff --git a/src/libpanic_unwind/dwarf/tests.rs b/src/libpanic_unwind/dwarf/tests.rs
deleted file mode 100644
index 1644f37083a..00000000000
--- a/src/libpanic_unwind/dwarf/tests.rs
+++ /dev/null
@@ -1,19 +0,0 @@
-use super::*;
-
-#[test]
-fn dwarf_reader() {
-    let encoded: &[u8] = &[1, 2, 3, 4, 5, 6, 7, 0xE5, 0x8E, 0x26, 0x9B, 0xF1, 0x59, 0xFF, 0xFF];
-
-    let mut reader = DwarfReader::new(encoded.as_ptr());
-
-    unsafe {
-        assert!(reader.read::<u8>() == u8::to_be(1u8));
-        assert!(reader.read::<u16>() == u16::to_be(0x0203));
-        assert!(reader.read::<u32>() == u32::to_be(0x04050607));
-
-        assert!(reader.read_uleb128() == 624485);
-        assert!(reader.read_sleb128() == -624485);
-
-        assert!(reader.read::<i8>() == i8::to_be(-1));
-    }
-}