Implement sections_start_alignment to allow aligning individual sec…

…tions Closes #66
decompals · Jul 12, 2024 · adf6e79 · adf6e79
1 parent 9af7dc7
commit adf6e79
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diff --git a/docs/file_format/segments.md b/docs/file_format/segments.md
@@ -59,14 +59,18 @@ Every attribute listed is optional unless explicitly stated.
     - [Example](#example-11)
     - [Valid values](#valid-values-10)
     - [Default value](#default-value-9)
-  - [`wildcard_sections`](#wildcard_sections)
+  - [`sections_start_alignment`](#sections_start_alignment)
     - [Example](#example-12)
     - [Valid values](#valid-values-11)
     - [Default value](#default-value-10)
-  - [`fill_value`](#fill_value)
+  - [`wildcard_sections`](#wildcard_sections)
     - [Example](#example-13)
     - [Valid values](#valid-values-12)
     - [Default value](#default-value-11)
+  - [`fill_value`](#fill_value)
+    - [Example](#example-14)
+    - [Valid values](#valid-values-13)
+    - [Default value](#default-value-12)
 
 ## `name`
 
@@ -383,6 +387,35 @@ Positive integers or `null`.
 The value specified for
 [settings.md#section_end_align](settings.md#section_end_align)
 
+## `sections_start_alignment`
+
+Allows to specify different alignments for the start of every section of this
+specific segment.
+
+If a specific section is not pressent on this mapping then no alignment will be
+forced on the given section.
+
+This option overrides the global setting, see
+[settings.md#sections_start_alignment](settings.md#sections_start_alignment) for
+more info.
+
+### Example
+
+```yaml
+segments:
+  - name: main
+    section_start_alignment: { .text: 4, .rodata: 0x10, .data: 0x20 }
+```
+
+### Valid values
+
+A mapping of strings as keys and positive numbers as values.
+
+### Default value
+
+The value specified for
+[settings.md#sections_start_alignment](settings.md#sections_start_alignment)
+
 ## `wildcard_sections`
 
 Toggles using wildcards (`*`) as suffix in the emitted sections for this

diff --git a/docs/file_format/settings.md b/docs/file_format/settings.md
@@ -87,14 +87,18 @@ as well.
     - [Example](#example-19)
     - [Valid values](#valid-values-19)
     - [Default value](#default-value-14)
-  - [`wildcard_sections`](#wildcard_sections)
+  - [`sections_start_alignment`](#sections_start_alignment)
     - [Example](#example-20)
     - [Valid values](#valid-values-20)
     - [Default value](#default-value-15)
-  - [`fill_value`](#fill_value)
+  - [`wildcard_sections`](#wildcard_sections)
     - [Example](#example-21)
     - [Valid values](#valid-values-21)
     - [Default value](#default-value-16)
+  - [`fill_value`](#fill_value)
+    - [Example](#example-22)
+    - [Valid values](#valid-values-22)
+    - [Default value](#default-value-17)
 
 ## `base_path`
 
@@ -627,6 +631,32 @@ Positive integers or `null`.
 
 `0x10`
 
+## `sections_start_alignment`
+
+Allows to specify different alignments for the start of every section.
+
+If a specific section is not pressent on this mapping then no alignment will be
+forced on the given section.
+
+This option can be overriden per segment, see
+[segments.md#sections_start_alignment](segments.md#sections_start_alignment) for
+more info.
+
+### Example
+
+```yaml
+settings:
+  section_start_alignment: { .text: 128, .rodata: 0x40, .sdata: 0x8 }
+```
+
+### Valid values
+
+A mapping of strings as keys and positive numbers as values.
+
+### Default value
+
+Empty mapping.
+
 ## `wildcard_sections`
 
 Toggles using wildcards (`*`) as suffix in the emitted sections.

diff --git a/slinky/src/document.rs b/slinky/src/document.rs
@@ -118,7 +118,13 @@ impl Document {
         Ok(new_path)
     }
 
-    pub(crate) fn should_emit_entry(&self, exclude_if_any: &[(String, String)], exclude_if_all: &[(String, String)], include_if_any: &[(String, String)], include_if_all: &[(String, String)]) -> bool {
+    pub(crate) fn should_emit_entry(
+        &self,
+        exclude_if_any: &[(String, String)],
+        exclude_if_all: &[(String, String)],
+        include_if_any: &[(String, String)],
+        include_if_all: &[(String, String)],
+    ) -> bool {
         if exclude_if_any
             .iter()
             .any(|(key, value)| self.custom_options.get(key) == Some(value))

diff --git a/slinky/src/linker_writer.rs b/slinky/src/linker_writer.rs
@@ -175,7 +175,12 @@ impl<'a> LinkerWriter<'a> {
     }
 
     pub fn add_segment(&mut self, segment: &Segment) -> Result<(), SlinkyError> {
-        if !self.d.should_emit_entry(&segment.exclude_if_any, &segment.exclude_if_all, &segment.include_if_any, &segment.include_if_all) {
+        if !self.d.should_emit_entry(
+            &segment.exclude_if_any,
+            &segment.exclude_if_all,
+            &segment.include_if_any,
+            &segment.include_if_all,
+        ) {
             return Ok(());
         }
 
@@ -559,6 +564,9 @@ impl LinkerWriter<'_> {
 
             let section_start_sym = style.segment_section_start(&segment.name, section);
 
+            if let Some(align_value) = segment.sections_start_alignment.get(section) {
+                self.buffer.align_symbol(".", *align_value);
+            }
             self.buffer.write_symbol(&section_start_sym, ".");
         }
     }
@@ -624,7 +632,12 @@ impl LinkerWriter<'_> {
         section: &str,
         base_path: &Path,
     ) -> Result<(), SlinkyError> {
-        if !self.d.should_emit_entry(&file.exclude_if_any, &file.exclude_if_all, &file.include_if_any, &file.include_if_all) {
+        if !self.d.should_emit_entry(
+            &file.exclude_if_any,
+            &file.exclude_if_all,
+            &file.include_if_any,
+            &file.include_if_all,
+        ) {
             return Ok(());
         }
 

diff --git a/slinky/src/segment.rs b/slinky/src/segment.rs
@@ -1,7 +1,7 @@
 /* SPDX-FileCopyrightText: © 2024 decompals */
 /* SPDX-License-Identifier: MIT */
 
-use std::path::PathBuf;
+use std::{collections::HashMap, path::PathBuf};
 
 use serde::Deserialize;
 
@@ -50,6 +50,7 @@ pub struct Segment {
     pub subalign: Option<u32>,
     pub segment_start_align: Option<u32>,
     pub section_end_align: Option<u32>,
+    pub sections_start_alignment: HashMap<String, u32>,
 
     pub wildcard_sections: bool,
 
@@ -98,6 +99,8 @@ pub(crate) struct SegmentSerial {
     pub segment_start_align: AbsentNullable<u32>,
     #[serde(default)]
     pub section_end_align: AbsentNullable<u32>,
+    #[serde(default)]
+    pub sections_start_alignment: AbsentNullable<HashMap<String, u32>>,
 
     #[serde(default)]
     pub wildcard_sections: AbsentNullable<bool>,
@@ -187,17 +190,17 @@ impl SegmentSerial {
         let dir = self.dir.get_non_null("dir", PathBuf::new)?;
 
         let include_if_any = self
-        .include_if_any
-        .get_non_null("include_if_any", Vec::new)?;
-    let include_if_all = self
-        .include_if_all
-        .get_non_null("include_if_all", Vec::new)?;
-    let exclude_if_any = self
-        .exclude_if_any
-        .get_non_null("exclude_if_any", Vec::new)?;
-    let exclude_if_all = self
-        .exclude_if_all
-        .get_non_null("exclude_if_all", Vec::new)?;
+            .include_if_any
+            .get_non_null("include_if_any", Vec::new)?;
+        let include_if_all = self
+            .include_if_all
+            .get_non_null("include_if_all", Vec::new)?;
+        let exclude_if_any = self
+            .exclude_if_any
+            .get_non_null("exclude_if_any", Vec::new)?;
+        let exclude_if_all = self
+            .exclude_if_all
+            .get_non_null("exclude_if_all", Vec::new)?;
 
         let alloc_sections = self
             .alloc_sections
@@ -218,6 +221,12 @@ impl SegmentSerial {
             .section_end_align
             .get_optional_nullable("section_end_align", || settings.section_end_align)?;
 
+        let sections_start_alignment = self
+            .sections_start_alignment
+            .get_non_null("sections_start_alignment", || {
+                settings.sections_start_alignment.clone()
+            })?;
+
         let wildcard_sections = self
             .wildcard_sections
             .get_non_null("wildcard_sections", || settings.wildcard_sections)?;
@@ -243,6 +252,7 @@ impl SegmentSerial {
             subalign,
             segment_start_align,
             section_end_align,
+            sections_start_alignment,
             wildcard_sections,
             fill_value,
         })

diff --git a/slinky/src/settings.rs b/slinky/src/settings.rs
@@ -2,7 +2,7 @@
 /* SPDX-License-Identifier: MIT */
 
 use serde::Deserialize;
-use std::path::PathBuf;
+use std::{collections::HashMap, path::PathBuf};
 
 use crate::{
     absent_nullable::AbsentNullable, linker_symbols_style::LinkerSymbolsStyle, SlinkyError,
@@ -39,6 +39,7 @@ pub struct Settings {
     pub subalign: Option<u32>,
     pub segment_start_align: Option<u32>,
     pub section_end_align: Option<u32>,
+    pub sections_start_alignment: HashMap<String, u32>,
 
     pub wildcard_sections: bool,
 
@@ -144,6 +145,10 @@ const fn settings_default_section_end_align() -> Option<u32> {
     Some(0x10)
 }
 
+fn settings_default_sections_start_alignment() -> HashMap<String, u32> {
+    HashMap::new()
+}
+
 const fn settings_default_wildcard_sections() -> bool {
     true
 }
@@ -183,6 +188,7 @@ impl Default for Settings {
             subalign: settings_default_subalign(),
             segment_start_align: settings_default_segment_start_align(),
             section_end_align: settings_default_section_end_align(),
+            sections_start_alignment: settings_default_sections_start_alignment(),
 
             wildcard_sections: settings_default_wildcard_sections(),
 
@@ -243,6 +249,8 @@ pub(crate) struct SettingsSerial {
     pub segment_start_align: AbsentNullable<u32>,
     #[serde(default)]
     pub section_end_align: AbsentNullable<u32>,
+    #[serde(default)]
+    pub sections_start_alignment: AbsentNullable<HashMap<String, u32>>,
 
     #[serde(default)]
     pub wildcard_sections: AbsentNullable<bool>,
@@ -337,6 +345,11 @@ impl SettingsSerial {
             .section_end_align
             .get_optional_nullable("section_end_align", settings_default_section_end_align)?;
 
+        let sections_start_alignment = self.sections_start_alignment.get_non_null(
+            "sections_start_alignment",
+            settings_default_sections_start_alignment,
+        )?;
+
         let wildcard_sections = self
             .wildcard_sections
             .get_non_null("wildcard_sections", settings_default_wildcard_sections)?;
@@ -372,6 +385,7 @@ impl SettingsSerial {
             subalign,
             segment_start_align,
             section_end_align,
+            sections_start_alignment,
             wildcard_sections,
             fill_value,
         })