Rework section alignment handling

- Honor splits.txt alignment values when writing ldscript.lcf
- Add alignment values to ldscript_partial.lcf, remove hacky code from rel make
- Guess alignment values in DOL loader

Fixes #27

assets/ldscript_partial.lcf

@@ -2,13 +2,7 @@ SECTIONS
 {
     GROUP:
     {
-        .init   :{}
-        .text   :{}
-        .ctors  :{}
-        .dtors  :{}
-        .rodata :{}
-        .data   :{ *(.data) *(extabindex) *(extab) }
-        .bss    :{}
+        $SECTIONS
     }
 }
 

src/cmd/rel.rs

@@ -30,7 +30,7 @@ use crate::{
     cmd::dol::{ModuleConfig, ProjectConfig},
     obj::{ObjInfo, ObjReloc, ObjRelocKind, ObjSection, ObjSectionKind, ObjSymbol},
     util::{
-        config::{is_auto_symbol, read_splits_sections, SectionDef},
+        config::is_auto_symbol,
         dol::process_dol,
         elf::{to_obj_reloc_kind, write_elf},
         file::{buf_reader, buf_writer, map_file, process_rsp, verify_hash, FileIterator},
@@ -170,12 +170,7 @@ fn load_rel(module_config: &ModuleConfig) -> Result<RelInfo> {
     let mut reader = file.as_reader();
     let header = process_rel_header(&mut reader)?;
     let sections = process_rel_sections(&mut reader, &header)?;
-    let section_defs = if let Some(splits_path) = &module_config.splits {
-        read_splits_sections(splits_path)?
-    } else {
-        None
-    };
-    Ok((header, sections, section_defs))
+    Ok((header, sections))
 }
 
 fn resolve_relocations(
@@ -191,8 +186,7 @@ fn resolve_relocations(
         if !matches!(section.name(), Ok(name) if PERMITTED_SECTIONS.contains(&name)) {
             continue;
         }
-        let section_index =
-            if let Some((_, sections, _)) = existing_headers.get(&(module_id as u32)) {
+        let section_index = if let Some((_, sections)) = existing_headers.get(&(module_id as u32)) {
             match_section_index(module, section.index(), sections)?
         } else {
             section.index().0
@@ -223,7 +217,7 @@ fn resolve_relocations(
                 (module_id, reloc_target)
             };
             let target_section_index = target_symbol.section_index().unwrap();
-            let target_section = if let Some((_, sections, _)) =
+            let target_section = if let Some((_, sections)) =
                 existing_headers.get(&(target_module_id as u32))
             {
                 match_section_index(&modules[target_module_id].0, target_section_index, sections)?
@@ -246,7 +240,7 @@ fn resolve_relocations(
     Ok(resolved)
 }
 
-type RelInfo = (RelHeader, Vec<RelSectionHeader>, Option<Vec<SectionDef>>);
+type RelInfo = (RelHeader, Vec<RelSectionHeader>);
 
 fn make(args: MakeArgs) -> Result<()> {
     let total = Instant::now();
@@ -347,17 +341,13 @@ fn make(args: MakeArgs) -> Result<()> {
             quiet: args.no_warn,
             section_align: None,
         };
-        if let Some((header, _, section_defs)) = existing_headers.get(&(module_id as u32)) {
+        if let Some((header, _)) = existing_headers.get(&(module_id as u32)) {
             info.version = header.version;
             info.name_offset = Some(header.name_offset);
             info.name_size = Some(header.name_size);
             info.align = header.align;
             info.bss_align = header.bss_align;
             info.section_count = Some(header.num_sections as usize);
-            info.section_align = section_defs
-                .as_ref()
-                .map(|defs| defs.iter().map(|def| def.align).collect())
-                .unwrap_or_default();
         }
         let rel_path = path.with_extension("rel");
         let mut w = buf_writer(&rel_path)?;

src/util/dol.rs

@@ -15,6 +15,7 @@ use crate::{
     },
     util::{
         alf::{AlfFile, AlfSymbol, ALF_MAGIC},
+        align_up,
         reader::{skip_bytes, Endian, FromReader},
     },
 };
@@ -555,6 +556,26 @@ pub fn process_dol(buf: &[u8], name: &str) -> Result<ObjInfo> {
         section.elf_index = idx + 1;
     }
 
+    // Guess section alignment
+    let mut last_section_end = sections.first().map_or(0, |s| s.address as u32);
+    for section in &mut sections {
+        let section_start = section.address as u32;
+        let mut align = 4;
+        while align_up(last_section_end, align) < section_start {
+            align = (align + 1).next_power_of_two();
+        }
+        if align_up(last_section_end, align) != section_start {
+            bail!(
+                "Couldn't determine alignment for section '{}' ({:#010X} -> {:#010X})",
+                section.name,
+                last_section_end,
+                section_start
+            );
+        }
+        last_section_end = section_start + section.size as u32;
+        section.align = align as u64;
+    }
+
     // Create object
     let mut obj = ObjInfo::new(
         ObjKind::Executable,

src/util/lcf.rs

@@ -1,13 +1,10 @@
 use std::path::PathBuf;
 
-use anyhow::{bail, Result};
+use anyhow::Result;
 use itertools::Itertools;
 use path_slash::PathBufExt;
 
-use crate::{
-    obj::{ObjInfo, ObjKind},
-    util::align_up,
-};
+use crate::obj::{ObjInfo, ObjKind};
 
 const LCF_TEMPLATE: &str = include_str!("../../assets/ldscript.lcf");
 const LCF_PARTIAL_TEMPLATE: &str = include_str!("../../assets/ldscript_partial.lcf");
@@ -27,32 +24,10 @@ pub fn generate_ldscript(
         _ => 65535, // default
     };
 
-    // Guess section alignment
-    let mut alignments = Vec::with_capacity(obj.sections.count());
-    let mut last_section_end = origin as u32;
-    for (_, section) in obj.sections.iter() {
-        let section_start = section.address as u32;
-        let mut align = 0x20;
-        while align_up(last_section_end, align) < section_start {
-            align = (align + 1).next_power_of_two();
-        }
-        if align_up(last_section_end, align) != section_start {
-            bail!(
-                "Couldn't determine alignment for section '{}' ({:#010X} -> {:#010X})",
-                section.name,
-                last_section_end,
-                section_start
-            );
-        }
-        last_section_end = section_start + section.size as u32;
-        alignments.push(align);
-    }
-
     let section_defs = obj
         .sections
         .iter()
-        .zip(alignments)
-        .map(|((_, s), align)| format!("{} ALIGN({:#X}):{{}}", s.name, align))
+        .map(|(_, s)| format!("{} ALIGN({:#X}):{{}}", s.name, s.align))
         .join("\n        ");
 
     let mut force_files = Vec::with_capacity(obj.link_order.len());
@@ -89,6 +64,15 @@ pub fn generate_ldscript_partial(
     template: Option<&str>,
     force_active: &[String],
 ) -> Result<String> {
+    let section_defs = obj
+        .sections
+        .iter()
+        .map(|(_, s)| {
+            let inner = if s.name == ".data" { " *(.data) *(extabindex) *(extab) " } else { "" };
+            format!("{} ALIGN({:#X}):{{{}}}", s.name, s.align, inner)
+        })
+        .join("\n        ");
+
     let mut force_files = Vec::with_capacity(obj.link_order.len());
     for unit in &obj.link_order {
         let obj_path = obj_path_for_unit(&unit.name);
@@ -104,6 +88,7 @@ pub fn generate_ldscript_partial(
 
     let out = template
         .unwrap_or(LCF_PARTIAL_TEMPLATE)
+        .replace("$SECTIONS", &section_defs)
         .replace("$FORCEACTIVE", &force_active.join("\n    "));
     Ok(out)
 }