mips: Ignore .NON_MATCHING functions from INLINE_ASM macros

Author: encounter

objdiff-cli/src/cmd/report.rs

@@ -232,6 +232,7 @@ fn report_object(
             if symbol.section != Some(section_idx)
                 || symbol.size == 0
                 || symbol.flags.contains(SymbolFlag::Hidden)
+                || symbol.flags.contains(SymbolFlag::Ignored)
             {
                 continue;
             }

objdiff-core/src/arch/mips.rs

@@ -1,4 +1,8 @@
-use alloc::{collections::BTreeMap, string::ToString, vec::Vec};
+use alloc::{
+    collections::{BTreeMap, BTreeSet},
+    string::ToString,
+    vec::Vec,
+};
 use core::ops::Range;
 
 use anyhow::{Result, bail};
@@ -15,7 +19,7 @@ use crate::{
     diff::{DiffObjConfig, MipsAbi, MipsInstrCategory, display::InstructionPart},
     obj::{
         InstructionArg, InstructionArgValue, InstructionRef, Relocation, RelocationFlags,
-        ResolvedInstructionRef, ResolvedRelocation, ScannedInstruction,
+        ResolvedInstructionRef, ResolvedRelocation, ScannedInstruction, SymbolFlag, SymbolFlagSet,
     },
 };
 
@@ -26,6 +30,7 @@ pub struct ArchMips {
     pub isa_extension: Option<IsaExtension>,
     pub ri_gp_value: i32,
     pub paired_relocations: Vec<BTreeMap<u64, i64>>,
+    pub ignored_symbols: BTreeSet<usize>,
 }
 
 const EF_MIPS_ABI: u32 = 0x0000F000;
@@ -118,7 +123,25 @@ impl ArchMips {
             paired_relocations[section_index] = addends;
         }
 
-        Ok(Self { endianness, abi, isa_extension, ri_gp_value, paired_relocations })
+        let mut ignored_symbols = BTreeSet::new();
+        for obj_symbol in object.symbols() {
+            let Ok(name) = obj_symbol.name() else { continue };
+            if let Some(prefix) = name.strip_suffix(".NON_MATCHING") {
+                ignored_symbols.insert(obj_symbol.index().0);
+                if let Some(target_symbol) = object.symbol_by_name(prefix) {
+                    ignored_symbols.insert(target_symbol.index().0);
+                }
+            }
+        }
+
+        Ok(Self {
+            endianness,
+            abi,
+            isa_extension,
+            ri_gp_value,
+            paired_relocations,
+            ignored_symbols,
+        })
     }
 
     fn instruction_flags(&self, diff_config: &DiffObjConfig) -> rabbitizer::InstructionFlags {
@@ -294,6 +317,14 @@ impl Arch for ArchMips {
             _ => 1,
         }
     }
+
+    fn extra_symbol_flags(&self, symbol: &object::Symbol) -> SymbolFlagSet {
+        let mut flags = SymbolFlagSet::default();
+        if self.ignored_symbols.contains(&symbol.index().0) {
+            flags |= SymbolFlag::Ignored;
+        }
+        flags
+    }
 }
 
 fn push_args(

objdiff-core/src/diff/data.rs

@@ -139,27 +139,13 @@ pub fn diff_data_section(
 ) -> Result<(SectionDiff, SectionDiff)> {
     let left_section = &left_obj.sections[left_section_idx];
     let right_section = &right_obj.sections[right_section_idx];
-    let left_max = left_obj
-        .symbols
-        .iter()
-        .filter_map(|s| {
-            if s.section != Some(left_section_idx) || s.kind == SymbolKind::Section {
-                return None;
-            }
-            s.address.checked_sub(left_section.address).map(|a| a + s.size)
-        })
+    let left_max = symbols_matching_section(&left_obj.symbols, left_section_idx)
+        .filter_map(|(_, s)| s.address.checked_sub(left_section.address).map(|a| a + s.size))
         .max()
         .unwrap_or(0)
         .min(left_section.size);
-    let right_max = right_obj
-        .symbols
-        .iter()
-        .filter_map(|s| {
-            if s.section != Some(right_section_idx) || s.kind == SymbolKind::Section {
-                return None;
-            }
-            s.address.checked_sub(right_section.address).map(|a| a + s.size)
-        })
+    let right_max = symbols_matching_section(&right_obj.symbols, right_section_idx)
+        .filter_map(|(_, s)| s.address.checked_sub(right_section.address).map(|a| a + s.size))
         .max()
         .unwrap_or(0)
         .min(right_section.size);
@@ -412,21 +398,13 @@ pub fn diff_generic_section(
     left_section_idx: usize,
     _right_section_idx: usize,
 ) -> Result<(SectionDiff, SectionDiff)> {
-    let match_percent = if left_obj
-        .symbols
-        .iter()
-        .enumerate()
-        .filter(|(_, s)| s.section == Some(left_section_idx) && s.kind != SymbolKind::Section)
+    let match_percent = if symbols_matching_section(&left_obj.symbols, left_section_idx)
         .map(|(i, _)| &left_diff.symbols[i])
         .all(|d| d.match_percent == Some(100.0))
     {
         100.0 // Avoid fp precision issues
     } else {
-        let (matched, total) = left_obj
-            .symbols
-            .iter()
-            .enumerate()
-            .filter(|(_, s)| s.section == Some(left_section_idx) && s.kind != SymbolKind::Section)
+        let (matched, total) = symbols_matching_section(&left_obj.symbols, left_section_idx)
             .map(|(i, s)| (s, &left_diff.symbols[i]))
             .fold((0.0, 0.0), |(matched, total), (s, d)| {
                 (matched + d.match_percent.unwrap_or(0.0) * s.size as f32, total + s.size as f32)
@@ -449,19 +427,11 @@ pub fn diff_bss_section(
     right_section_idx: usize,
 ) -> Result<(SectionDiff, SectionDiff)> {
     let left_section = &left_obj.sections[left_section_idx];
-    let left_sizes = left_obj
-        .symbols
-        .iter()
-        .enumerate()
-        .filter(|(_, s)| s.section == Some(left_section_idx) && s.kind != SymbolKind::Section)
+    let left_sizes = symbols_matching_section(&left_obj.symbols, left_section_idx)
         .filter_map(|(_, s)| s.address.checked_sub(left_section.address).map(|a| (a, s.size)))
         .collect::<Vec<_>>();
     let right_section = &right_obj.sections[right_section_idx];
-    let right_sizes = right_obj
-        .symbols
-        .iter()
-        .enumerate()
-        .filter(|(_, s)| s.section == Some(right_section_idx) && s.kind != SymbolKind::Section)
+    let right_sizes = symbols_matching_section(&right_obj.symbols, right_section_idx)
         .filter_map(|(_, s)| s.address.checked_sub(right_section.address).map(|a| (a, s.size)))
         .collect::<Vec<_>>();
     let ops = capture_diff_slices(Algorithm::Patience, &left_sizes, &right_sizes);
@@ -487,3 +457,15 @@ pub fn diff_bss_section(
         SectionDiff { match_percent: Some(match_percent), data_diff: vec![], reloc_diff: vec![] },
     ))
 }
+
+fn symbols_matching_section(
+    symbols: &[Symbol],
+    section_idx: usize,
+) -> impl Iterator<Item = (usize, &Symbol)> + '_ {
+    symbols.iter().enumerate().filter(move |(_, s)| {
+        s.section == Some(section_idx)
+            && s.kind != SymbolKind::Section
+            && s.size > 0
+            && !s.flags.contains(SymbolFlag::Ignored)
+    })
+}

objdiff-core/src/diff/display.rs

@@ -580,7 +580,11 @@ fn symbol_matches_filter(
     if symbol.section.is_none() && !symbol.flags.contains(SymbolFlag::Common) {
         return false;
     }
-    if !show_hidden_symbols && (symbol.size == 0 || symbol.flags.contains(SymbolFlag::Hidden)) {
+    if !show_hidden_symbols
+        && (symbol.size == 0
+            || symbol.flags.contains(SymbolFlag::Hidden)
+            || symbol.flags.contains(SymbolFlag::Ignored))
+    {
         return false;
     }
     match filter {

objdiff-core/src/diff/mod.rs

@@ -371,7 +371,10 @@ fn generate_mapping_symbols(
     };
     let base_section_kind = symbol_section_kind(base_obj, &base_obj.symbols[base_symbol_ref]);
     for (target_symbol_index, target_symbol) in target_obj.symbols.iter().enumerate() {
-        if symbol_section_kind(target_obj, target_symbol) != base_section_kind {
+        if target_symbol.size == 0
+            || target_symbol.flags.contains(SymbolFlag::Ignored)
+            || symbol_section_kind(target_obj, target_symbol) != base_section_kind
+        {
             continue;
         }
         match base_section_kind {
@@ -526,6 +529,9 @@ fn matching_symbols(
             )?;
         }
         for (symbol_idx, symbol) in left.symbols.iter().enumerate() {
+            if symbol.size == 0 || symbol.flags.contains(SymbolFlag::Ignored) {
+                continue;
+            }
             let section_kind = symbol_section_kind(left, symbol);
             if section_kind == SectionKind::Unknown {
                 continue;
@@ -547,6 +553,9 @@ fn matching_symbols(
     }
     if let Some(right) = right {
         for (symbol_idx, symbol) in right.symbols.iter().enumerate() {
+            if symbol.size == 0 || symbol.flags.contains(SymbolFlag::Ignored) {
+                continue;
+            }
             let section_kind = symbol_section_kind(right, symbol);
             if section_kind == SectionKind::Unknown {
                 continue;
@@ -572,9 +581,10 @@ fn unmatched_symbols<'obj, 'used>(
 where
     'obj: 'used,
 {
-    obj.symbols.iter().enumerate().filter(move |&(symbol_idx, _)| {
-        // Skip symbols that have already been matched
-        !used.is_some_and(|u| u.contains(&symbol_idx))
+    obj.symbols.iter().enumerate().filter(move |&(symbol_idx, symbol)| {
+        !symbol.flags.contains(SymbolFlag::Ignored)
+            // Skip symbols that have already been matched
+            && !used.is_some_and(|u| u.contains(&symbol_idx))
     })
 }
 

objdiff-core/src/obj/mod.rs

@@ -42,6 +42,8 @@ flags! {
         HasExtra,
         /// Symbol size was missing and was inferred
         SizeInferred,
+        /// Symbol should be ignored by any diffing
+        Ignored,
     }
 }
 

objdiff-core/tests/arch_mips.rs

@@ -37,3 +37,11 @@ fn cross_endian_diff() {
     assert_eq!(left_diff.instruction_rows[2].kind, diff::InstructionDiffKind::None);
     assert_eq!(right_diff.instruction_rows[2].kind, diff::InstructionDiffKind::None);
 }
+
+#[test]
+#[cfg(feature = "mips")]
+fn filter_non_matching() {
+    let diff_config = diff::DiffObjConfig::default();
+    let obj = obj::read::parse(include_object!("data/mips/vw_main.c.o"), &diff_config).unwrap();
+    insta::assert_debug_snapshot!(obj.symbols);
+}