From c3de306156696e01d8c240250b81c2daf0ca5c37 Mon Sep 17 00:00:00 2001
From: Sai Asish Y <say.apm35@gmail.com>
Date: Fri, 12 Jun 2026 23:55:24 -0700
Subject: [PATCH] Fix ARM panic when a code section has no mapping symbols

Signed-off-by: Sai Asish Y <say.apm35@gmail.com>
---
 objdiff-core/src/arch/arm.rs            |   1 +
 objdiff-core/tests/arch_arm.rs          |  19 +++++++++++++++++++
 objdiff-core/tests/data/arm/issue_352.o | Bin 0 -> 1020 bytes
 3 files changed, 20 insertions(+)
 create mode 100644 objdiff-core/tests/data/arm/issue_352.o

diff --git a/objdiff-core/src/arch/arm.rs b/objdiff-core/src/arch/arm.rs
index 35416c9f..ba839cdd 100644
--- a/objdiff-core/src/arch/arm.rs
+++ b/objdiff-core/src/arch/arm.rs
@@ -184,6 +184,7 @@ impl Arch for ArchArm {
             .disasm_modes
             .get(&section_index)
             .map(|x| x.as_slice())
+            .filter(|x| !x.is_empty())
             .unwrap_or(&fallback_mappings);
         let first_mapping_idx = mapping_symbols
             .binary_search_by_key(&start_addr, |x| x.address)
diff --git a/objdiff-core/tests/arch_arm.rs b/objdiff-core/tests/arch_arm.rs
index 9c507e1d..caab3a71 100644
--- a/objdiff-core/tests/arch_arm.rs
+++ b/objdiff-core/tests/arch_arm.rs
@@ -98,3 +98,22 @@ fn trim_trailing_hword() {
     let output = common::display_diff(&obj, &diff, symbol_idx, &diff_config);
     insta::assert_snapshot!(output);
 }
+
+#[test]
+#[cfg(feature = "arm")]
+fn no_mapping_symbols_in_text() {
+    // A .text section that contains code bytes but is not covered by any
+    // mapping symbol must not panic while scanning instructions.
+    let diff_config = diff::DiffObjConfig::default();
+    let obj = obj::read::parse(
+        include_object!("data/arm/issue_352.o"),
+        &diff_config,
+        diff::DiffSide::Base,
+    )
+    .unwrap();
+    for (symbol_idx, symbol) in obj.symbols.iter().enumerate() {
+        if symbol.section.is_some() && symbol.size > 0 {
+            let _ = diff::code::no_diff_code(&obj, symbol_idx, &diff_config);
+        }
+    }
+}
diff --git a/objdiff-core/tests/data/arm/issue_352.o b/objdiff-core/tests/data/arm/issue_352.o
new file mode 100644
index 0000000000000000000000000000000000000000..6b13eaa79697e42cd8e5aa147d3d07968f01ff3d
GIT binary patch
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zGl&ENy^_?55(d5EjN+1_lEfq+3r1Jwg84<MIf;58mq64LL4y1R!fa5rpfukGWrHYa
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tX;8`qsR3aDAQl8-n4Lf-LkLh)D2M?CFnd8M99i8CpgJ9xA|MS@2LO6g_96fP

literal 0
HcmV?d00001