Implement section_end_align

Fixes #25

docs/file_format/segments.md

@@ -154,6 +154,32 @@ Positive integers or `null`.
 
 The value specified for [settings.md#subalign](settings.md#subalign)
 
+## `section_end_align`
+
+Force aligning the end of each section for this segment to the specified value.
+
+If the value is `null` then no alignment will be forced on the end of the
+sections of this segment.
+
+This option overrides the global setting, see
+[settings.md#section_end_align](settings.md#section_end_align) for more info.
+
+### Example
+
+```yaml
+segments:
+  - name: main
+    section_end_align: null
+```
+
+### Valid values
+
+Positive integers or `null`.
+
+### Default value
+
+The value specified for [settings.md#section_end_align](settings.md#section_end_align)
+
 ## `wildcard_sections`
 
 Toggles using wildcards (`*`) as suffix in the emitted sections for this

docs/file_format/settings.md

@@ -275,7 +275,32 @@ Positive integers or `null`.
 
 ### Default value
 
-`16`
+`0x10`
+
+## `section_end_align`
+
+Force aligning the end of each section to the specified value.
+
+If the value is `null` then no alignment will be forced on the end of the
+sections.
+
+This option can be overriden per segment, see
+[segments.md#section_end_align](segments.md#section_end_align) for more info.
+
+### Example
+
+```yaml
+settings:
+  section_end_align: 0x10
+```
+
+### Valid values
+
+Positive integers or `null`.
+
+### Default value
+
+`0x10`
 
 ## `wildcard_sections`
 

slinky/src/linker_writer.rs

@@ -284,7 +284,7 @@ impl LinkerWriter<'_> {
         self.write_sym_end_size(seg_sym_start, seg_sym_end, seg_sym_size, ".");
     }
 
-    fn write_files_for_section(&mut self, segment: &Segment, section: &str) {
+    fn emit_section(&mut self, segment: &Segment, section: &str) {
         let style = &self.settings.linker_symbols_style;
 
         for file in &segment.files {
@@ -352,8 +352,11 @@ impl LinkerWriter<'_> {
 
             self.write_symbol(&section_start_sym, ".");
 
-            self.write_files_for_section(segment, section);
+            self.emit_section(segment, section);
 
+            if let Some(section_end_align) = segment.section_end_align {
+                self.writeln(&format!(". = ALIGN(0x{:X})", section_end_align));
+            }
             self.write_sym_end_size(&section_start_sym, &section_end_sym, &section_size_sym, ".");
 
             if i + 1 < sections.len() {

slinky/src/segment.rs

@@ -30,6 +30,7 @@ pub struct Segment {
     pub noload_sections: Vec<String>,
 
     pub subalign: Option<u32>,
+    pub section_end_align: Option<u32>,
 
     pub wildcard_sections: bool,
 
@@ -54,6 +55,8 @@ pub(crate) struct SegmentSerial {
 
     #[serde(default)]
     pub subalign: AbsentNullable<u32>,
+    #[serde(default)]
+    pub section_end_align: AbsentNullable<u32>,
 
     #[serde(default)]
     pub wildcard_sections: AbsentNullable<bool>,
@@ -108,6 +111,10 @@ impl SegmentSerial {
             .subalign
             .get_optional_nullable("subalign", || settings.subalign)?;
 
+        let section_end_align = self
+            .section_end_align
+            .get_optional_nullable("section_end_align", || settings.section_end_align)?;
+
         let wildcard_sections = self
             .wildcard_sections
             .get_non_null("wildcard_sections", || settings.wildcard_sections)?;
@@ -124,6 +131,7 @@ impl SegmentSerial {
             alloc_sections,
             noload_sections,
             subalign,
+            section_end_align,
             wildcard_sections,
             fill_value,
         })

slinky/src/settings.rs

@@ -25,6 +25,7 @@ pub struct Settings {
     pub noload_sections: Vec<String>,
 
     pub subalign: Option<u32>,
+    pub section_end_align: Option<u32>,
 
     pub wildcard_sections: bool,
 
@@ -87,7 +88,11 @@ fn settings_default_noload_sections() -> Vec<String> {
 }
 
 fn settings_default_subalign() -> Option<u32> {
-    Some(16)
+    Some(0x10)
+}
+
+fn settings_default_section_end_align() -> Option<u32> {
+    Some(0x10)
 }
 
 fn settings_default_wildcard_sections() -> bool {
@@ -115,6 +120,7 @@ impl Default for Settings {
             noload_sections: settings_default_noload_sections(),
 
             subalign: settings_default_subalign(),
+            section_end_align: settings_default_section_end_align(),
 
             wildcard_sections: settings_default_wildcard_sections(),
 
@@ -143,14 +149,16 @@ pub(crate) struct SettingsSerial {
     #[serde(default)]
     pub discard_wildcard_section: AbsentNullable<bool>,
 
+    // Options passed down to each Segment
     #[serde(default)]
     pub alloc_sections: AbsentNullable<Vec<String>>,
     #[serde(default)]
     pub noload_sections: AbsentNullable<Vec<String>>,
 
-    // Options passed down to each Segment
     #[serde(default)]
     pub subalign: AbsentNullable<u32>,
+    #[serde(default)]
+    pub section_end_align: AbsentNullable<u32>,
 
     #[serde(default)]
     pub wildcard_sections: AbsentNullable<bool>,
@@ -199,6 +207,10 @@ impl SettingsSerial {
             .subalign
             .get_optional_nullable("subalign", settings_default_subalign)?;
 
+        let section_end_align = self
+            .section_end_align
+            .get_optional_nullable("section_end_align", settings_default_section_end_align)?;
+
         let wildcard_sections = self
             .wildcard_sections
             .get_non_null("wildcard_sections", settings_default_wildcard_sections)?;
@@ -218,6 +230,7 @@ impl SettingsSerial {
             alloc_sections,
             noload_sections,
             subalign,
+            section_end_align,
             wildcard_sections,
             fill_value,
         })

tests/input_files/follow_segment.yaml

@@ -1,5 +1,6 @@
 settings:
   base_path: build
+  section_end_align: null
 
 segments:
   - name: boot
@@ -13,6 +14,7 @@ segments:
 
   - name: main
     follows_segment: boot
+    section_end_align: 0x20
     files:
       - { path: src/main/main.o }
       - { path: src/main/dmadata.o }

tests/input_files/pad_test.yaml

@@ -1,5 +1,6 @@
 settings:
   base_path: build
+  section_end_align: null
 
 segments:
   - name: boot

tests/linker_scripts/archives.ld

@@ -20,6 +20,7 @@ SECTIONS
         build/lib/libmus.a:aud_thread.o(.text*);
         build/lib/libmus.a:lib_memory.o(.text*);
         build/lib/libmus.a:aud_samples.o(.text*);
+        . = ALIGN(0x10)
         boot_TEXT_END = .;
         boot_TEXT_SIZE = ABSOLUTE(boot_TEXT_END - boot_TEXT_START);
 
@@ -35,6 +36,7 @@ SECTIONS
         build/lib/libmus.a:aud_thread.o(.data*);
         build/lib/libmus.a:lib_memory.o(.data*);
         build/lib/libmus.a:aud_samples.o(.data*);
+        . = ALIGN(0x10)
         boot_DATA_END = .;
         boot_DATA_SIZE = ABSOLUTE(boot_DATA_END - boot_DATA_START);
 
@@ -50,6 +52,7 @@ SECTIONS
         build/lib/libmus.a:aud_thread.o(.rodata*);
         build/lib/libmus.a:lib_memory.o(.rodata*);
         build/lib/libmus.a:aud_samples.o(.rodata*);
+        . = ALIGN(0x10)
         boot_RODATA_END = .;
         boot_RODATA_SIZE = ABSOLUTE(boot_RODATA_END - boot_RODATA_START);
 
@@ -65,6 +68,7 @@ SECTIONS
         build/lib/libmus.a:aud_thread.o(.sdata*);
         build/lib/libmus.a:lib_memory.o(.sdata*);
         build/lib/libmus.a:aud_samples.o(.sdata*);
+        . = ALIGN(0x10)
         boot_SDATA_END = .;
         boot_SDATA_SIZE = ABSOLUTE(boot_SDATA_END - boot_SDATA_START);
     }
@@ -87,6 +91,7 @@ SECTIONS
         build/lib/libmus.a:aud_thread.o(.sbss*);
         build/lib/libmus.a:lib_memory.o(.sbss*);
         build/lib/libmus.a:aud_samples.o(.sbss*);
+        . = ALIGN(0x10)
         boot_SBSS_END = .;
         boot_SBSS_SIZE = ABSOLUTE(boot_SBSS_END - boot_SBSS_START);
 
@@ -102,6 +107,7 @@ SECTIONS
         build/lib/libmus.a:aud_thread.o(.scommon*);
         build/lib/libmus.a:lib_memory.o(.scommon*);
         build/lib/libmus.a:aud_samples.o(.scommon*);
+        . = ALIGN(0x10)
         boot_SCOMMON_END = .;
         boot_SCOMMON_SIZE = ABSOLUTE(boot_SCOMMON_END - boot_SCOMMON_START);
 
@@ -117,6 +123,7 @@ SECTIONS
         build/lib/libmus.a:aud_thread.o(.bss*);
         build/lib/libmus.a:lib_memory.o(.bss*);
         build/lib/libmus.a:aud_samples.o(.bss*);
+        . = ALIGN(0x10)
         boot_BSS_END = .;
         boot_BSS_SIZE = ABSOLUTE(boot_BSS_END - boot_BSS_START);
 
@@ -132,6 +139,7 @@ SECTIONS
         build/lib/libmus.a:aud_thread.o(COMMON*);
         build/lib/libmus.a:lib_memory.o(COMMON*);
         build/lib/libmus.a:aud_samples.o(COMMON*);
+        . = ALIGN(0x10)
         bootCOMMON_END = .;
         bootCOMMON_SIZE = ABSOLUTE(bootCOMMON_END - bootCOMMON_START);
     }