From 7ec5467b5ad67e6f0398c47cfc3759eb87466a83 Mon Sep 17 00:00:00 2001
From: omiinaya <omiinaya@mrxlab.net>
Date: Tue, 20 Oct 2026 23:51:43 -0400
Subject: [PATCH] Don't abandon the extab search at a gap between sections

locate_extab_extabindex() probes for _eti_init_info starting at
section_end - ETI_INIT_INFO_SIZE * (num_text_sections + 1) and walks forward, reading
a candidate table at each address. A section's size can stop short of the next
section: sizes come from _rom_copy_info, whose values are rounded differently from the
file's. The first candidate then lands in the gap, read_eti_init_info() fails with
"Failed to locate section @ <addr>", and the `?` on it abandoned the search for the
whole program -- so extab/extabindex were never named.

The result is a game that splits with no exception-table splits at all, or, once
anything names extabindex, a hard failure: "Failed to find extab section".

Clamp the first candidate to the section start, and treat an unreadable candidate as
"not this one" instead of aborting. Also give the end-of-table read in the second loop
a message that says what it was doing.

Reproduced with v1.8.4 on Sonic Adventure 2 Battle's DOL ("Failed to locate section @
0x80173124", the program has no extab) and on a DOL with Animal Crossing's section
layout (.init 0x80003100 stopping at 0x800055F0, extab 0x80005620, extabindex
0x80005660, _eti_init_info 0x80005684), where the warning is gone after the change.
For the Sonic DOL the split output (config.json, splits.txt, symbols.txt) is
byte-identical to v1.8.4's.
---
 src/util/dol.rs | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/util/dol.rs b/src/util/dol.rs
index 3ad425a8..bb809a35 100644
--- a/src/util/dol.rs
+++ b/src/util/dol.rs
@@ -871,16 +871,31 @@ fn locate_extab_extabindex(obj: &mut ObjInfo) -> Result<()> {
         let dol_section_start = dol_section.address as u32;
         let dol_section_end = dol_section_start + dol_section.size as u32;
         let eti_init_info_addr = {
-            let mut addr = dol_section_end - (ETI_INIT_INFO_SIZE * (num_text_sections + 1)) as u32;
+            // A section's size can stop short of the next section (the copied-to-RAM size in _rom_copy_info
+            // is often rounded differently from the file's), leaving gaps in the section map. A candidate
+            // address that lands in one says nothing about the others: skip it, don't abandon the search.
+            let lowest = dol_section_end
+                .saturating_sub((ETI_INIT_INFO_SIZE * (num_text_sections + 1)) as u32)
+                .max(dol_section_start);
+            let mut addr = lowest;
             loop {
-                let eti_init_info = read_eti_init_info(obj, addr)?;
+                let eti_init_info = match read_eti_init_info(obj, addr) {
+                    Ok(eti_init_info) => eti_init_info,
+                    Err(_) => {
+                        addr += 4;
+                        if addr > dol_section_end.saturating_sub(ETI_INIT_INFO_SIZE as u32) {
+                            continue 'outer;
+                        }
+                        continue;
+                    }
+                };
                 if validate_eti_init_info(obj, &eti_init_info, dol_section_start, dol_section_end)?
                 {
                     log::debug!("Found _eti_init_info @ {addr:#010X}");
                     break addr;
                 }
                 addr += 4;
-                if addr > dol_section_end - ETI_INIT_INFO_SIZE as u32 {
+                if addr > dol_section_end.saturating_sub(ETI_INIT_INFO_SIZE as u32) {
                     continue 'outer;
                 }
             }
@@ -889,7 +904,12 @@ fn locate_extab_extabindex(obj: &mut ObjInfo) -> Result<()> {
         let eti_init_info_end = {
             let mut addr = eti_init_info_addr;
             loop {
-                let eti_init_info = read_eti_init_info(obj, addr)?;
+                let Ok(eti_init_info) = read_eti_init_info(obj, addr) else {
+                    bail!(
+                        "Failed to locate _eti_init_info end (start @ {:#010X})",
+                        eti_init_info_addr
+                    );
+                };
                 addr += 16;
                 if eti_init_info.is_zero() {
                     break;