1 files changed, 117 insertions, 0 deletions
diff --git a/third_party/rust/object/src/read/elf/dynamic.rs b/third_party/rust/object/src/read/elf/dynamic.rs
new file mode 100644
index 0000000000..5fe15b560d
--- /dev/null
+++ b/third_party/rust/object/src/read/elf/dynamic.rs
@@ -0,0 +1,117 @@
+use core::convert::TryInto;
+use core::fmt::Debug;
+
+use crate::elf;
+use crate::endian;
+use crate::pod::Pod;
+use crate::read::{ReadError, Result, StringTable};
+
+/// A trait for generic access to `Dyn32` and `Dyn64`.
+#[allow(missing_docs)]
+pub trait Dyn: Debug + Pod {
+    type Word: Into<u64>;
+    type Endian: endian::Endian;
+
+    fn d_tag(&self, endian: Self::Endian) -> Self::Word;
+    fn d_val(&self, endian: Self::Endian) -> Self::Word;
+
+    /// Try to convert the tag to a `u32`.
+    fn tag32(&self, endian: Self::Endian) -> Option<u32> {
+        self.d_tag(endian).into().try_into().ok()
+    }
+
+    /// Try to convert the value to a `u32`.
+    fn val32(&self, endian: Self::Endian) -> Option<u32> {
+        self.d_val(endian).into().try_into().ok()
+    }
+
+    /// Return true if the value is an offset in the dynamic string table.
+    fn is_string(&self, endian: Self::Endian) -> bool {
+        if let Some(tag) = self.tag32(endian) {
+            match tag {
+                elf::DT_NEEDED
+                | elf::DT_SONAME
+                | elf::DT_RPATH
+                | elf::DT_RUNPATH
+                | elf::DT_AUXILIARY
+                | elf::DT_FILTER => true,
+                _ => false,
+            }
+        } else {
+            false
+        }
+    }
+
+    /// Use the value to get a string in a string table.
+    ///
+    /// Does not check for an appropriate tag.
+    fn string<'data>(
+        &self,
+        endian: Self::Endian,
+        strings: StringTable<'data>,
+    ) -> Result<&'data [u8]> {
+        self.val32(endian)
+            .and_then(|val| strings.get(val).ok())
+            .read_error("Invalid ELF dyn string")
+    }
+
+    /// Return true if the value is an address.
+    fn is_address(&self, endian: Self::Endian) -> bool {
+        if let Some(tag) = self.tag32(endian) {
+            match tag {
+                elf::DT_PLTGOT
+                | elf::DT_HASH
+                | elf::DT_STRTAB
+                | elf::DT_SYMTAB
+                | elf::DT_RELA
+                | elf::DT_INIT
+                | elf::DT_FINI
+                | elf::DT_SYMBOLIC
+                | elf::DT_REL
+                | elf::DT_DEBUG
+                | elf::DT_JMPREL
+                | elf::DT_FINI_ARRAY
+                | elf::DT_INIT_ARRAY
+                | elf::DT_PREINIT_ARRAY
+                | elf::DT_SYMTAB_SHNDX
+                | elf::DT_VERDEF
+                | elf::DT_VERNEED
+                | elf::DT_VERSYM
+                | elf::DT_ADDRRNGLO..=elf::DT_ADDRRNGHI => true,
+                _ => false,
+            }
+        } else {
+            false
+        }
+    }
+}
+
+impl<Endian: endian::Endian> Dyn for elf::Dyn32<Endian> {
+    type Word = u32;
+    type Endian = Endian;
+
+    #[inline]
+    fn d_tag(&self, endian: Self::Endian) -> Self::Word {
+        self.d_tag.get(endian)
+    }
+
+    #[inline]
+    fn d_val(&self, endian: Self::Endian) -> Self::Word {
+        self.d_val.get(endian)
+    }
+}
+
+impl<Endian: endian::Endian> Dyn for elf::Dyn64<Endian> {
+    type Word = u64;
+    type Endian = Endian;
+
+    #[inline]
+    fn d_tag(&self, endian: Self::Endian) -> Self::Word {
+        self.d_tag.get(endian)
+    }
+
+    #[inline]
+    fn d_val(&self, endian: Self::Endian) -> Self::Word {
+        self.d_val.get(endian)
+    }
+}