elf+dwarf: refer sections via section symbols

3 files changed, 100 insertions, 106 deletions

diff --git a/src/link/Dwarf.zig b/src/link/Dwarf.zig
index c3197f7651..332c79e0fc 100644
--- a/src/link/Dwarf.zig
+++ b/src/link/Dwarf.zig
@@ -375,12 +375,17 @@ pub const Section = struct {
     fn resize(sec: *Section, dwarf: *Dwarf, len: u64) UpdateError!void {
         if (len <= sec.len) return;
         if (dwarf.bin_file.cast(.elf)) |elf_file| {
+            const zo = elf_file.zigObjectPtr().?;
+            const atom = zo.symbol(sec.index).atom(elf_file).?;
+            const shndx = atom.output_section_index;
             if (sec == &dwarf.debug_frame.section)
-                try elf_file.growAllocSection(sec.index, len)
+                try elf_file.growAllocSection(shndx, len)
             else
-                try elf_file.growNonAllocSection(sec.index, len, @intCast(sec.alignment.toByteUnits().?), true);
-            const shdr = &elf_file.sections.items(.shdr)[sec.index];
-            sec.off = shdr.sh_offset;
+                try elf_file.growNonAllocSection(shndx, len, @intCast(sec.alignment.toByteUnits().?), true);
+            const shdr = elf_file.sections.items(.shdr)[shndx];
+            atom.size = shdr.sh_size;
+            atom.alignment = InternPool.Alignment.fromNonzeroByteUnits(shdr.sh_addralign);
+            sec.off = shdr.sh_offset + @as(u64, @intCast(atom.value));
             sec.len = shdr.sh_size;
         } else if (dwarf.bin_file.cast(.macho)) |macho_file| {
             const header = if (macho_file.d_sym) |*d_sym| header: {
@@ -402,7 +407,11 @@ pub const Section = struct {
         sec.off += len;
         sec.len -= len;
         if (dwarf.bin_file.cast(.elf)) |elf_file| {
-            const shdr = &elf_file.sections.items(.shdr)[sec.index];
+            const zo = elf_file.zigObjectPtr().?;
+            const atom = zo.symbol(sec.index).atom(elf_file).?;
+            const shndx = atom.output_section_index;
+            const shdr = &elf_file.sections.items(.shdr)[shndx];
+            atom.size = sec.len;
             shdr.sh_offset = sec.off;
             shdr.sh_size = sec.len;
         } else if (dwarf.bin_file.cast(.macho)) |macho_file| {
@@ -891,9 +900,11 @@ const Entry = struct {
         if (std.debug.runtime_safety) {
             log.err("missing {} from {s}", .{
                 @as(Entry.Index, @enumFromInt(entry - unit.entries.items.ptr)),
-                std.mem.sliceTo(if (dwarf.bin_file.cast(.elf)) |elf_file|
-                    elf_file.shstrtab.items[elf_file.sections.items(.shdr)[sec.index].sh_name..]
-                else if (dwarf.bin_file.cast(.macho)) |macho_file|
+                std.mem.sliceTo(if (dwarf.bin_file.cast(.elf)) |elf_file| sh_name: {
+                    const zo = elf_file.zigObjectPtr().?;
+                    const shndx = zo.symbol(sec.index).atom(elf_file).?.output_section_index;
+                    break :sh_name elf_file.shstrtab.items[elf_file.sections.items(.shdr)[shndx].sh_name..];
+                } else if (dwarf.bin_file.cast(.macho)) |macho_file|
                     if (macho_file.d_sym) |*d_sym|
                         &d_sym.sections.items[sec.index].segname
                     else
@@ -961,7 +972,8 @@ const Entry = struct {
             .none, .debug_frame => {},
             .eh_frame => return if (dwarf.bin_file.cast(.elf)) |elf_file| {
                 const zo = elf_file.zigObjectPtr().?;
-                const entry_addr: i64 = @intCast(entry_off - sec.off + elf_file.shdrs.items[sec.index].sh_addr);
+                const shndx = zo.symbol(sec.index).atom(elf_file).?.output_section_index;
+                const entry_addr: i64 = @intCast(entry_off - sec.off + elf_file.shdrs.items[shndx].sh_addr);
                 for (entry.external_relocs.items) |reloc| {
                     const symbol = zo.symbol(reloc.target_sym);
                     try dwarf.resolveReloc(
@@ -1877,34 +1889,7 @@ pub fn init(lf: *link.File, format: DW.Format) Dwarf {
 }
 
 pub fn reloadSectionMetadata(dwarf: *Dwarf) void {
-    if (dwarf.bin_file.cast(.elf)) |elf_file| {
-        for ([_]*Section{
-            &dwarf.debug_abbrev.section,
-            &dwarf.debug_aranges.section,
-            &dwarf.debug_frame.section,
-            &dwarf.debug_info.section,
-            &dwarf.debug_line.section,
-            &dwarf.debug_line_str.section,
-            &dwarf.debug_loclists.section,
-            &dwarf.debug_rnglists.section,
-            &dwarf.debug_str.section,
-        }, [_]u32{
-            elf_file.debug_abbrev_section_index.?,
-            elf_file.debug_aranges_section_index.?,
-            elf_file.eh_frame_section_index.?,
-            elf_file.debug_info_section_index.?,
-            elf_file.debug_line_section_index.?,
-            elf_file.debug_line_str_section_index.?,
-            elf_file.debug_loclists_section_index.?,
-            elf_file.debug_rnglists_section_index.?,
-            elf_file.debug_str_section_index.?,
-        }) |sec, section_index| {
-            const shdr = &elf_file.sections.items(.shdr)[section_index];
-            sec.index = section_index;
-            sec.off = shdr.sh_offset;
-            sec.len = shdr.sh_size;
-        }
-    } else if (dwarf.bin_file.cast(.macho)) |macho_file| {
+    if (dwarf.bin_file.cast(.macho)) |macho_file| {
         if (macho_file.d_sym) |*d_sym| {
             for ([_]*Section{
                 &dwarf.debug_abbrev.section,
@@ -1960,6 +1945,32 @@ pub fn reloadSectionMetadata(dwarf: *Dwarf) void {
 }
 
 pub fn initMetadata(dwarf: *Dwarf) UpdateError!void {
+    if (dwarf.bin_file.cast(.elf)) |elf_file| {
+        const zo = elf_file.zigObjectPtr().?;
+        for ([_]*Section{
+            &dwarf.debug_abbrev.section,
+            &dwarf.debug_aranges.section,
+            &dwarf.debug_frame.section,
+            &dwarf.debug_info.section,
+            &dwarf.debug_line.section,
+            &dwarf.debug_line_str.section,
+            &dwarf.debug_loclists.section,
+            &dwarf.debug_rnglists.section,
+            &dwarf.debug_str.section,
+        }, [_]u32{
+            zo.debug_abbrev_index.?,
+            zo.debug_aranges_index.?,
+            zo.eh_frame_index.?,
+            zo.debug_info_index.?,
+            zo.debug_line_index.?,
+            zo.debug_line_str_index.?,
+            zo.debug_loclists_index.?,
+            zo.debug_rnglists_index.?,
+            zo.debug_str_index.?,
+        }) |sec, sym_index| {
+            sec.index = sym_index;
+        }
+    }
     dwarf.reloadSectionMetadata();
 
     dwarf.debug_abbrev.section.pad_to_ideal = false;
diff --git a/src/link/Elf.zig b/src/link/Elf.zig
index d44892836c..2940759009 100644
--- a/src/link/Elf.zig
+++ b/src/link/Elf.zig
@@ -114,15 +114,6 @@ rela_plt: std.ArrayListUnmanaged(elf.Elf64_Rela) = .{},
 /// Applies only to a relocatable.
 comdat_group_sections: std.ArrayListUnmanaged(ComdatGroupSection) = .{},
 
-debug_info_section_index: ?u32 = null,
-debug_abbrev_section_index: ?u32 = null,
-debug_str_section_index: ?u32 = null,
-debug_aranges_section_index: ?u32 = null,
-debug_line_section_index: ?u32 = null,
-debug_line_str_section_index: ?u32 = null,
-debug_loclists_section_index: ?u32 = null,
-debug_rnglists_section_index: ?u32 = null,
-
 copy_rel_section_index: ?u32 = null,
 dynamic_section_index: ?u32 = null,
 dynstrtab_section_index: ?u32 = null,
@@ -636,24 +627,31 @@ pub fn growNonAllocSection(
 }
 
 pub fn markDirty(self: *Elf, shdr_index: u32) void {
-    const zig_object = self.zigObjectPtr().?;
-    if (zig_object.dwarf) |_| {
-        if (self.debug_info_section_index.? == shdr_index) {
-            zig_object.debug_info_section_dirty = true;
-        } else if (self.debug_abbrev_section_index.? == shdr_index) {
-            zig_object.debug_abbrev_section_dirty = true;
-        } else if (self.debug_str_section_index.? == shdr_index) {
-            zig_object.debug_str_section_dirty = true;
-        } else if (self.debug_aranges_section_index.? == shdr_index) {
-            zig_object.debug_aranges_section_dirty = true;
-        } else if (self.debug_line_section_index.? == shdr_index) {
-            zig_object.debug_line_section_dirty = true;
-        } else if (self.debug_line_str_section_index.? == shdr_index) {
-            zig_object.debug_line_str_section_dirty = true;
-        } else if (self.debug_loclists_section_index.? == shdr_index) {
-            zig_object.debug_loclists_section_dirty = true;
-        } else if (self.debug_rnglists_section_index.? == shdr_index) {
-            zig_object.debug_rnglists_section_dirty = true;
+    if (self.zigObjectPtr()) |zo| {
+        for ([_]?Symbol.Index{
+            zo.debug_info_index,
+            zo.debug_abbrev_index,
+            zo.debug_aranges_index,
+            zo.debug_str_index,
+            zo.debug_line_index,
+            zo.debug_line_str_index,
+            zo.debug_loclists_index,
+            zo.debug_rnglists_index,
+        }, [_]*bool{
+            &zo.debug_info_section_dirty,
+            &zo.debug_abbrev_section_dirty,
+            &zo.debug_aranges_section_dirty,
+            &zo.debug_str_section_dirty,
+            &zo.debug_line_section_dirty,
+            &zo.debug_line_str_section_dirty,
+            &zo.debug_loclists_section_dirty,
+            &zo.debug_rnglists_section_dirty,
+        }) |maybe_sym_index, dirty| {
+            const sym_index = maybe_sym_index orelse continue;
+            if (zo.symbol(sym_index).atom(self).?.output_section_index == shdr_index) {
+                dirty.* = true;
+                break;
+            }
         }
     }
 }
@@ -3473,14 +3471,6 @@ fn resetShdrIndexes(self: *Elf, backlinks: []const u32) void {
         &self.copy_rel_section_index,
         &self.versym_section_index,
         &self.verneed_section_index,
-        &self.debug_info_section_index,
-        &self.debug_abbrev_section_index,
-        &self.debug_str_section_index,
-        &self.debug_aranges_section_index,
-        &self.debug_line_section_index,
-        &self.debug_line_str_section_index,
-        &self.debug_loclists_section_index,
-        &self.debug_rnglists_section_index,
     }) |maybe_index| {
         if (maybe_index.*) |*index| {
             index.* = backlinks[index.*];
@@ -3505,7 +3495,6 @@ fn resetShdrIndexes(self: *Elf, backlinks: []const u32) void {
             const atom_ptr = zo.atom(atom_index) orelse continue;
             atom_ptr.output_section_index = backlinks[atom_ptr.output_section_index];
         }
-        if (zo.dwarf) |*dwarf| dwarf.reloadSectionMetadata();
     }
 
     for (self.comdat_group_sections.items) |*cg| {
diff --git a/src/link/Elf/ZigObject.zig b/src/link/Elf/ZigObject.zig
index 27fb121b04..8de8551463 100644
--- a/src/link/Elf/ZigObject.zig
+++ b/src/link/Elf/ZigObject.zig
@@ -99,8 +99,8 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
         .dwarf => |v| {
             var dwarf = Dwarf.init(&elf_file.base, v);
 
-            if (elf_file.debug_str_section_index == null) {
-                elf_file.debug_str_section_index = try elf_file.addSection(.{
+            if (self.debug_str_index == null) {
+                const osec = try elf_file.addSection(.{
                     .name = try elf_file.insertShString(".debug_str"),
                     .flags = elf.SHF_MERGE | elf.SHF_STRINGS,
                     .entsize = 1,
@@ -108,51 +108,51 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
                     .addralign = 1,
                 });
                 self.debug_str_section_dirty = true;
-                self.debug_str_index = try self.addSectionSymbol(gpa, ".debug_str", .@"1", elf_file.debug_str_section_index.?);
+                self.debug_str_index = try self.addSectionSymbol(gpa, ".debug_str", .@"1", osec);
             }
 
-            if (elf_file.debug_info_section_index == null) {
-                elf_file.debug_info_section_index = try elf_file.addSection(.{
+            if (self.debug_info_index == null) {
+                const osec = try elf_file.addSection(.{
                     .name = try elf_file.insertShString(".debug_info"),
                     .type = elf.SHT_PROGBITS,
                     .addralign = 1,
                 });
                 self.debug_info_section_dirty = true;
-                self.debug_info_index = try self.addSectionSymbol(gpa, ".debug_info", .@"1", elf_file.debug_info_section_index.?);
+                self.debug_info_index = try self.addSectionSymbol(gpa, ".debug_info", .@"1", osec);
             }
 
-            if (elf_file.debug_abbrev_section_index == null) {
-                elf_file.debug_abbrev_section_index = try elf_file.addSection(.{
+            if (self.debug_abbrev_index == null) {
+                const osec = try elf_file.addSection(.{
                     .name = try elf_file.insertShString(".debug_abbrev"),
                     .type = elf.SHT_PROGBITS,
                     .addralign = 1,
                 });
                 self.debug_abbrev_section_dirty = true;
-                self.debug_abbrev_index = try self.addSectionSymbol(gpa, ".debug_abbrev", .@"1", elf_file.debug_abbrev_section_index.?);
+                self.debug_abbrev_index = try self.addSectionSymbol(gpa, ".debug_abbrev", .@"1", osec);
             }
 
-            if (elf_file.debug_aranges_section_index == null) {
-                elf_file.debug_aranges_section_index = try elf_file.addSection(.{
+            if (self.debug_aranges_index == null) {
+                const osec = try elf_file.addSection(.{
                     .name = try elf_file.insertShString(".debug_aranges"),
                     .type = elf.SHT_PROGBITS,
                     .addralign = 16,
                 });
                 self.debug_aranges_section_dirty = true;
-                self.debug_aranges_index = try self.addSectionSymbol(gpa, ".debug_aranges", .@"16", elf_file.debug_aranges_section_index.?);
+                self.debug_aranges_index = try self.addSectionSymbol(gpa, ".debug_aranges", .@"16", osec);
             }
 
-            if (elf_file.debug_line_section_index == null) {
-                elf_file.debug_line_section_index = try elf_file.addSection(.{
+            if (self.debug_line_index == null) {
+                const osec = try elf_file.addSection(.{
                     .name = try elf_file.insertShString(".debug_line"),
                     .type = elf.SHT_PROGBITS,
                     .addralign = 1,
                 });
                 self.debug_line_section_dirty = true;
-                self.debug_line_index = try self.addSectionSymbol(gpa, ".debug_line", .@"1", elf_file.debug_line_section_index.?);
+                self.debug_line_index = try self.addSectionSymbol(gpa, ".debug_line", .@"1", osec);
             }
 
-            if (elf_file.debug_line_str_section_index == null) {
-                elf_file.debug_line_str_section_index = try elf_file.addSection(.{
+            if (self.debug_line_str_index == null) {
+                const osec = try elf_file.addSection(.{
                     .name = try elf_file.insertShString(".debug_line_str"),
                     .flags = elf.SHF_MERGE | elf.SHF_STRINGS,
                     .entsize = 1,
@@ -160,31 +160,31 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
                     .addralign = 1,
                 });
                 self.debug_line_str_section_dirty = true;
-                self.debug_line_str_index = try self.addSectionSymbol(gpa, ".debug_line_str", .@"1", elf_file.debug_line_str_section_index.?);
+                self.debug_line_str_index = try self.addSectionSymbol(gpa, ".debug_line_str", .@"1", osec);
             }
 
-            if (elf_file.debug_loclists_section_index == null) {
-                elf_file.debug_loclists_section_index = try elf_file.addSection(.{
+            if (self.debug_loclists_index == null) {
+                const osec = try elf_file.addSection(.{
                     .name = try elf_file.insertShString(".debug_loclists"),
                     .type = elf.SHT_PROGBITS,
                     .addralign = 1,
                 });
                 self.debug_loclists_section_dirty = true;
-                self.debug_loclists_index = try self.addSectionSymbol(gpa, ".debug_loclists", .@"1", elf_file.debug_loclists_section_index.?);
+                self.debug_loclists_index = try self.addSectionSymbol(gpa, ".debug_loclists", .@"1", osec);
             }
 
-            if (elf_file.debug_rnglists_section_index == null) {
-                elf_file.debug_rnglists_section_index = try elf_file.addSection(.{
+            if (self.debug_rnglists_index == null) {
+                const osec = try elf_file.addSection(.{
                     .name = try elf_file.insertShString(".debug_rnglists"),
                     .type = elf.SHT_PROGBITS,
                     .addralign = 1,
                 });
                 self.debug_rnglists_section_dirty = true;
-                self.debug_rnglists_index = try self.addSectionSymbol(gpa, ".debug_rnglists", .@"1", elf_file.debug_rnglists_section_index.?);
+                self.debug_rnglists_index = try self.addSectionSymbol(gpa, ".debug_rnglists", .@"1", osec);
             }
 
-            if (elf_file.eh_frame_section_index == null) {
-                elf_file.eh_frame_section_index = try elf_file.addSection(.{
+            if (self.eh_frame_index == null) {
+                const osec = try elf_file.addSection(.{
                     .name = try elf_file.insertShString(".eh_frame"),
                     .type = if (elf_file.getTarget().cpu.arch == .x86_64)
                         elf.SHT_X86_64_UNWIND
@@ -194,7 +194,7 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
                     .addralign = ptr_size,
                 });
                 self.eh_frame_section_dirty = true;
-                self.eh_frame_index = try self.addSectionSymbol(gpa, ".eh_frame", Atom.Alignment.fromNonzeroByteUnits(ptr_size), elf_file.eh_frame_section_index.?);
+                self.eh_frame_index = try self.addSectionSymbol(gpa, ".eh_frame", Atom.Alignment.fromNonzeroByteUnits(ptr_size), osec);
             }
 
             try dwarf.initMetadata();
@@ -328,12 +328,6 @@ pub fn flushModule(self: *ZigObject, elf_file: *Elf, tid: Zcu.PerThread.Id) !voi
             const sym = self.symbol(sym_index);
             const atom_ptr = self.atom(sym.ref.index).?;
             if (!atom_ptr.alive) continue;
-            const shndx = sym.outputShndx(elf_file).?;
-            const shdr = elf_file.sections.items(.shdr)[shndx];
-            const esym = &self.symtab.items(.elf_sym)[sym.esym_index];
-            esym.st_size = shdr.sh_size;
-            atom_ptr.size = shdr.sh_size;
-            atom_ptr.alignment = Atom.Alignment.fromNonzeroByteUnits(shdr.sh_addralign);
 
             log.debug("parsing relocs in {s}", .{sym.name(elf_file)});