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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-30 03:59:35 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-30 03:59:35 +0000 |
commit | d1b2d29528b7794b41e66fc2136e395a02f8529b (patch) | |
tree | a4a17504b260206dec3cf55b2dca82929a348ac2 /library/std/src/sys/personality/dwarf/mod.rs | |
parent | Releasing progress-linux version 1.72.1+dfsg1-1~progress7.99u1. (diff) | |
download | rustc-d1b2d29528b7794b41e66fc2136e395a02f8529b.tar.xz rustc-d1b2d29528b7794b41e66fc2136e395a02f8529b.zip |
Merging upstream version 1.73.0+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'library/std/src/sys/personality/dwarf/mod.rs')
-rw-r--r-- | library/std/src/sys/personality/dwarf/mod.rs | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/library/std/src/sys/personality/dwarf/mod.rs b/library/std/src/sys/personality/dwarf/mod.rs new file mode 100644 index 000000000..652fbe95a --- /dev/null +++ b/library/std/src/sys/personality/dwarf/mod.rs @@ -0,0 +1,73 @@ +//! 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: u32 = 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 < u64::BITS && (byte & 0x40) != 0 { + result |= (!0 as u64) << shift; + } + result as i64 + } +} |