Exception table diff view (#82)

* Basic integration

* Implement basic right click option

Needs lotsa work

* nothing to worry about

* Convert extab diff to separate view

* Make clippy and fmt shut up

* Make clippy fmt shut up for real this time

* Print extab/extabindex symbol names in extab view

* I hate fmt

* Basic integration

* Implement basic right click option

Needs lotsa work

* nothing to worry about

* Convert extab diff to separate view

* Make clippy and fmt shut up

* Make clippy fmt shut up for real this time

* Print extab/extabindex symbol names in extab view

* I hate fmt

* Fix scroll position not being maintained from extab view

* Silly me

* Add rlwinm decoder window

* Remove extra files

* Create Cargo.lock

* Show extab symbol names in hover window

* Appease fmt

* Update symbol_diff.rs

* Update symbol_diff.rs

* Get extab symbol from extabindex relocations instead

* Update Cargo.lock

* Update Cargo.lock

objdiff-core/Cargo.toml

@@ -17,7 +17,7 @@ any-arch = [] # Implicit, used to check if any arch is enabled
 config = ["globset", "semver", "serde_json", "serde_yaml"]
 dwarf = ["gimli"]
 mips = ["any-arch", "rabbitizer"]
-ppc = ["any-arch", "cwdemangle", "ppc750cl"]
+ppc = ["any-arch", "cwdemangle", "cwextab", "ppc750cl"]
 x86 = ["any-arch", "cpp_demangle", "iced-x86", "msvc-demangler"]
 arm = ["any-arch", "cpp_demangle", "unarm", "arm-attr"]
 
@@ -45,6 +45,7 @@ gimli = { version = "0.29.0", default-features = false, features = ["read-all"],
 
 # ppc
 cwdemangle = { version = "1.0.0", optional = true }
+cwextab = { version = "0.2.3", optional = true }
 ppc750cl = { git = "https://github.com/encounter/ppc750cl", rev = "6cbd7d888c7082c2c860f66cbb9848d633f753ed", optional = true }
 
 # mips

objdiff-core/src/obj/mod.rs

@@ -3,6 +3,7 @@ pub mod split_meta;
 
 use std::{borrow::Cow, collections::BTreeMap, fmt, path::PathBuf};
 
+use cwextab::*;
 use filetime::FileTime;
 use flagset::{flags, FlagSet};
 use object::RelocationFlags;
@@ -113,6 +114,9 @@ pub struct ObjIns {
 pub struct ObjSymbol {
     pub name: String,
     pub demangled_name: Option<String>,
+    pub has_extab: bool,
+    pub extab_name: Option<String>,
+    pub extabindex_name: Option<String>,
     pub address: u64,
     pub section_address: u64,
     pub size: u64,
@@ -123,6 +127,13 @@ pub struct ObjSymbol {
     pub virtual_address: Option<u64>,
 }
 
+#[derive(Debug, Clone)]
+pub struct ObjExtab {
+    pub func: ObjSymbol,
+    pub data: ExceptionTableData,
+    pub dtors: Vec<ObjSymbol>,
+}
+
 pub struct ObjInfo {
     pub arch: Box<dyn ObjArch>,
     pub path: PathBuf,
@@ -130,6 +141,8 @@ pub struct ObjInfo {
     pub sections: Vec<ObjSection>,
     /// Common BSS symbols
     pub common: Vec<ObjSymbol>,
+    /// Exception tables
+    pub extab: Option<Vec<ObjExtab>>,
     /// Split object metadata (.note.split section)
     pub split_meta: Option<SplitMeta>,
 }

objdiff-core/src/obj/read.rs

@@ -2,11 +2,12 @@ use std::{collections::HashSet, fs, io::Cursor, path::Path};
 
 use anyhow::{anyhow, bail, ensure, Context, Result};
 use byteorder::{BigEndian, ReadBytesExt};
+use cwextab::decode_extab;
 use filetime::FileTime;
 use flagset::Flags;
 use object::{
-    BinaryFormat, File, Object, ObjectSection, ObjectSymbol, RelocationTarget, SectionIndex,
-    SectionKind, Symbol, SymbolKind, SymbolScope, SymbolSection,
+    Architecture, BinaryFormat, File, Object, ObjectSection, ObjectSymbol, RelocationTarget,
+    SectionIndex, SectionKind, Symbol, SymbolKind, SymbolScope, SymbolSection,
 };
 
 use crate::{
@@ -14,7 +15,8 @@ use crate::{
     diff::DiffObjConfig,
     obj::{
         split_meta::{SplitMeta, SPLITMETA_SECTION},
-        ObjInfo, ObjReloc, ObjSection, ObjSectionKind, ObjSymbol, ObjSymbolFlagSet, ObjSymbolFlags,
+        ObjExtab, ObjInfo, ObjReloc, ObjSection, ObjSectionKind, ObjSymbol, ObjSymbolFlagSet,
+        ObjSymbolFlags,
     },
 };
 
@@ -71,6 +73,9 @@ fn to_obj_symbol(
     Ok(ObjSymbol {
         name: name.to_string(),
         demangled_name,
+        has_extab: false,
+        extab_name: None,
+        extabindex_name: None,
         address,
         section_address,
         size: symbol.size(),
@@ -170,6 +175,111 @@ fn common_symbols(
         .collect::<Result<Vec<ObjSymbol>>>()
 }
 
+fn section_by_name<'a>(sections: &'a mut [ObjSection], name: &str) -> Option<&'a mut ObjSection> {
+    sections.iter_mut().find(|section| section.name == name)
+}
+
+fn exception_tables(
+    sections: &mut [ObjSection],
+    obj_file: &File<'_>,
+) -> Result<Option<Vec<ObjExtab>>> {
+    //PowerPC only
+    if obj_file.architecture() != Architecture::PowerPc {
+        return Ok(None);
+    }
+
+    //Find the extab/extabindex sections
+    let extab_section = match section_by_name(sections, "extab") {
+        Some(section) => section.clone(),
+        None => {
+            return Ok(None);
+        }
+    };
+    let extabindex_section = match section_by_name(sections, "extabindex") {
+        Some(section) => section.clone(),
+        None => {
+            return Ok(None);
+        }
+    };
+    let text_section = match section_by_name(sections, ".text") {
+        Some(section) => section,
+        None => bail!(".text section is somehow missing, this should not happen"),
+    };
+
+    let mut result: Vec<ObjExtab> = vec![];
+    let extab_symbol_count = extab_section.symbols.len();
+    let extabindex_symbol_count = extabindex_section.symbols.len();
+    let extab_reloc_count = extab_section.relocations.len();
+    let table_count = extab_symbol_count;
+    let mut extab_reloc_index: usize = 0;
+
+    //Make sure that the number of symbols in the extab/extabindex section matches. If not, exit early
+    if extab_symbol_count != extabindex_symbol_count {
+        bail!("Extab/Extabindex symbol counts do not match");
+    }
+
+    //Convert the extab/extabindex section data
+
+    //Go through each extabindex entry
+    for i in 0..table_count {
+        let extabindex = &extabindex_section.symbols[i];
+
+        /* Get the function symbol and extab symbol from the extabindex relocations array. Each extabindex
+        entry has two relocations (the first for the function, the second for the extab entry) */
+        let extab_func = extabindex_section.relocations[i * 2].target.clone();
+        let extab = &extabindex_section.relocations[(i * 2) + 1].target;
+
+        let extab_start_addr = extab.address;
+        let extab_end_addr = extab_start_addr + extab.size;
+
+        //Find the function in the text section, and set the has extab flag
+        for i in 0..text_section.symbols.len() {
+            let func = &mut text_section.symbols[i];
+            if func.name == extab_func.name {
+                func.has_extab = true;
+                func.extab_name = Some(extab.name.clone());
+                func.extabindex_name = Some(extabindex.name.clone());
+            }
+        }
+
+        /* Iterate through the list of extab relocations, continuing until we hit a relocation
+        that isn't within the current extab symbol. Get the target dtor function symbol from
+        each relocation used, and add them to the list. */
+        let mut dtors: Vec<ObjSymbol> = vec![];
+
+        while extab_reloc_index < extab_reloc_count {
+            let extab_reloc = &extab_section.relocations[extab_reloc_index];
+            //If the current entry is past the current extab table, stop here
+            if extab_reloc.address >= extab_end_addr {
+                break;
+            }
+
+            //Otherwise, the current relocation is used by the current table
+            dtors.push(extab_reloc.target.clone());
+            //Go to the next entry
+            extab_reloc_index += 1;
+        }
+
+        //Decode the extab data
+        let start_index = extab_start_addr as usize;
+        let end_index = extab_end_addr as usize;
+        let extab_data = extab_section.data[start_index..end_index].try_into().unwrap();
+        let data = match decode_extab(extab_data) {
+            Some(decoded_data) => decoded_data,
+            None => {
+                log::warn!("Exception table decoding failed for function {}", extab_func.name);
+                return Ok(None);
+            }
+        };
+
+        //Add the new entry to the list
+        let entry = ObjExtab { func: extab_func, data, dtors };
+        result.push(entry);
+    }
+
+    Ok(Some(result))
+}
+
 fn find_section_symbol(
     arch: &dyn ObjArch,
     obj_file: &File<'_>,
@@ -205,6 +315,9 @@ fn find_section_symbol(
     Ok(ObjSymbol {
         name: name.to_string(),
         demangled_name: None,
+        has_extab: false,
+        extab_name: None,
+        extabindex_name: None,
         address: offset,
         section_address: address - section.address(),
         size: 0,
@@ -367,6 +480,9 @@ fn update_combined_symbol(symbol: ObjSymbol, address_change: i64) -> Result<ObjS
     Ok(ObjSymbol {
         name: symbol.name,
         demangled_name: symbol.demangled_name,
+        has_extab: symbol.has_extab,
+        extab_name: symbol.extab_name,
+        extabindex_name: symbol.extabindex_name,
         address: (symbol.address as i64 + address_change).try_into()?,
         section_address: (symbol.section_address as i64 + address_change).try_into()?,
         size: symbol.size,
@@ -482,7 +598,8 @@ pub fn read(obj_path: &Path, config: &DiffObjConfig) -> Result<ObjInfo> {
     }
     line_info(&obj_file, &mut sections)?;
     let common = common_symbols(arch.as_ref(), &obj_file, split_meta.as_ref())?;
-    Ok(ObjInfo { arch, path: obj_path.to_owned(), timestamp, sections, common, split_meta })
+    let extab = exception_tables(&mut sections, &obj_file)?;
+    Ok(ObjInfo { arch, path: obj_path.to_owned(), timestamp, sections, common, extab, split_meta })
 }
 
 pub fn has_function(obj_path: &Path, symbol_name: &str) -> Result<bool> {