authorgravatar for kubkon@jakubkonka.comJakub Konka <kubkon@jakubkonka.com> 2024-09-03 21:01:12+02:00
committergravatar for kubkon@jakubkonka.comJakub Konka <kubkon@jakubkonka.com> 2024-09-04 13:34:26+02:00
logeeec50d2515c5a3b65cab697ba3e28d89cc3b14c
treeec0b7769fa070c189aa605c00015ec943997b6b1
parentfca92fd7c0a2e1431338ef62440751870563a0e3

elf: misc .eh_frame management fixes

5 files changed, 64 insertions(+), 61 deletions(-)

src/link/Elf.zig+18-26
......@@ -621,7 +621,6 @@ pub fn growNonAllocSection(
621621 try self.base.file.?.setEndPos(shdr.sh_offset + needed_size);
622622 }
623623 shdr.sh_size = needed_size;
624
625624 self.markDirty(shdr_index);
626625}
627626
......@@ -2895,28 +2894,25 @@ fn initSyntheticSections(self: *Elf) !void {
28952894 const target = self.getTarget();
28962895 const ptr_size = self.ptrWidthBytes();
28972896
2898 const needs_eh_frame = if (self.zigObjectPtr()) |zo|
2899 zo.eh_frame_index != null
2900 else for (self.objects.items) |index| {
2901 if (self.file(index).?.object.cies.items.len > 0) break true;
2902 } else false;
2897 const needs_eh_frame = blk: {
2898 if (self.zigObjectPtr()) |zo|
2899 if (zo.eh_frame_index != null) break :blk true;
2900 break :blk for (self.objects.items) |index| {
2901 if (self.file(index).?.object.cies.items.len > 0) break true;
2902 } else false;
2903 };
29032904 if (needs_eh_frame) {
29042905 if (self.eh_frame_section_index == null) {
2905 self.eh_frame_section_index = blk: {
2906 if (self.zigObjectPtr()) |zo| {
2907 if (zo.eh_frame_index) |idx| break :blk zo.symbol(idx).atom(self).?.output_section_index;
2908 }
2909 break :blk try self.addSection(.{
2910 .name = try self.insertShString(".eh_frame"),
2911 .type = if (target.cpu.arch == .x86_64)
2912 elf.SHT_X86_64_UNWIND
2913 else
2914 elf.SHT_PROGBITS,
2915 .flags = elf.SHF_ALLOC,
2916 .addralign = ptr_size,
2917 .offset = std.math.maxInt(u64),
2918 });
2919 };
2906 self.eh_frame_section_index = self.sectionByName(".eh_frame") orelse try self.addSection(.{
2907 .name = try self.insertShString(".eh_frame"),
2908 .type = if (target.cpu.arch == .x86_64)
2909 elf.SHT_X86_64_UNWIND
2910 else
2911 elf.SHT_PROGBITS,
2912 .flags = elf.SHF_ALLOC,
2913 .addralign = ptr_size,
2914 .offset = std.math.maxInt(u64),
2915 });
29202916 }
29212917 if (comp.link_eh_frame_hdr) {
29222918 self.eh_frame_hdr_section_index = try self.addSection(.{
......@@ -3591,11 +3587,7 @@ fn updateSectionSizes(self: *Elf) !void {
35913587
35923588 const shdrs = slice.items(.shdr);
35933589 if (self.eh_frame_section_index) |index| {
3594 shdrs[index].sh_size = existing_size: {
3595 const zo = self.zigObjectPtr() orelse break :existing_size 0;
3596 const sym = zo.symbol(zo.eh_frame_index orelse break :existing_size 0);
3597 break :existing_size sym.atom(self).?.size;
3598 } + try eh_frame.calcEhFrameSize(self);
3590 shdrs[index].sh_size = try eh_frame.calcEhFrameSize(self);
35993591 }
36003592
36013593 if (self.eh_frame_hdr_section_index) |index| {
src/link/Elf/Object.zig+1
......@@ -1096,6 +1096,7 @@ pub fn initRelaSections(self: *Object, elf_file: *Elf) !void {
10961096 for (self.atoms_indexes.items) |atom_index| {
10971097 const atom_ptr = self.atom(atom_index) orelse continue;
10981098 if (!atom_ptr.alive) continue;
1099 if (atom_ptr.output_section_index == elf_file.eh_frame_section_index) continue;
10991100 const shndx = atom_ptr.relocsShndx() orelse continue;
11001101 const shdr = self.shdrs.items[shndx];
11011102 const out_shndx = try elf_file.initOutputSection(.{
src/link/Elf/ZigObject.zig+12
......@@ -111,6 +111,7 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
111111 });
112112 self.debug_str_section_dirty = true;
113113 self.debug_str_index = try self.addSectionSymbol(gpa, ".debug_str", .@"1", osec);
114 elf_file.sections.items(.last_atom)[osec] = self.symbol(self.debug_str_index.?).ref;
114115 }
115116
116117 if (self.debug_info_index == null) {
......@@ -121,6 +122,7 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
121122 });
122123 self.debug_info_section_dirty = true;
123124 self.debug_info_index = try self.addSectionSymbol(gpa, ".debug_info", .@"1", osec);
125 elf_file.sections.items(.last_atom)[osec] = self.symbol(self.debug_info_index.?).ref;
124126 }
125127
126128 if (self.debug_abbrev_index == null) {
......@@ -131,6 +133,7 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
131133 });
132134 self.debug_abbrev_section_dirty = true;
133135 self.debug_abbrev_index = try self.addSectionSymbol(gpa, ".debug_abbrev", .@"1", osec);
136 elf_file.sections.items(.last_atom)[osec] = self.symbol(self.debug_abbrev_index.?).ref;
134137 }
135138
136139 if (self.debug_aranges_index == null) {
......@@ -141,6 +144,7 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
141144 });
142145 self.debug_aranges_section_dirty = true;
143146 self.debug_aranges_index = try self.addSectionSymbol(gpa, ".debug_aranges", .@"16", osec);
147 elf_file.sections.items(.last_atom)[osec] = self.symbol(self.debug_aranges_index.?).ref;
144148 }
145149
146150 if (self.debug_line_index == null) {
......@@ -151,6 +155,7 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
151155 });
152156 self.debug_line_section_dirty = true;
153157 self.debug_line_index = try self.addSectionSymbol(gpa, ".debug_line", .@"1", osec);
158 elf_file.sections.items(.last_atom)[osec] = self.symbol(self.debug_line_index.?).ref;
154159 }
155160
156161 if (self.debug_line_str_index == null) {
......@@ -163,6 +168,7 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
163168 });
164169 self.debug_line_str_section_dirty = true;
165170 self.debug_line_str_index = try self.addSectionSymbol(gpa, ".debug_line_str", .@"1", osec);
171 elf_file.sections.items(.last_atom)[osec] = self.symbol(self.debug_line_str_index.?).ref;
166172 }
167173
168174 if (self.debug_loclists_index == null) {
......@@ -173,6 +179,7 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
173179 });
174180 self.debug_loclists_section_dirty = true;
175181 self.debug_loclists_index = try self.addSectionSymbol(gpa, ".debug_loclists", .@"1", osec);
182 elf_file.sections.items(.last_atom)[osec] = self.symbol(self.debug_loclists_index.?).ref;
176183 }
177184
178185 if (self.debug_rnglists_index == null) {
......@@ -183,6 +190,7 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
183190 });
184191 self.debug_rnglists_section_dirty = true;
185192 self.debug_rnglists_index = try self.addSectionSymbol(gpa, ".debug_rnglists", .@"1", osec);
193 elf_file.sections.items(.last_atom)[osec] = self.symbol(self.debug_rnglists_index.?).ref;
186194 }
187195
188196 if (self.eh_frame_index == null) {
......@@ -197,6 +205,7 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
197205 });
198206 self.eh_frame_section_dirty = true;
199207 self.eh_frame_index = try self.addSectionSymbol(gpa, ".eh_frame", Atom.Alignment.fromNonzeroByteUnits(ptr_size), osec);
208 elf_file.sections.items(.last_atom)[osec] = self.symbol(self.eh_frame_index.?).ref;
200209 }
201210
202211 try dwarf.initMetadata();
......@@ -1116,6 +1125,9 @@ pub fn getOrCreateMetadataForNav(
11161125 return gop.value_ptr.symbol_index;
11171126}
11181127
1128// FIXME: we always create an atom to basically store size and alignment, however, this is only true for
1129// sections that have a single atom like the debug sections. It would be a better solution to decouple this
1130// concept from the atom, maybe.
11191131fn addSectionSymbol(
11201132 self: *ZigObject,
11211133 allocator: Allocator,
src/link/Elf/eh_frame.zig+10-8
......@@ -233,7 +233,10 @@ pub fn calcEhFrameSize(elf_file: *Elf) !usize {
233233 const comp = elf_file.base.comp;
234234 const gpa = comp.gpa;
235235
236 var offset: usize = 0;
236 var offset: usize = if (elf_file.zigObjectPtr()) |zo| blk: {
237 const sym = zo.symbol(zo.eh_frame_index orelse break :blk 0);
238 break :blk sym.atom(elf_file).?.size;
239 } else 0;
237240
238241 var cies = std.ArrayList(Cie).init(gpa);
239242 defer cies.deinit();
......@@ -423,9 +426,8 @@ pub fn writeEhFrameRelocatable(elf_file: *Elf, writer: anytype) !void {
423426 }
424427}
425428
426fn emitReloc(elf_file: *Elf, base_offset: u64, sym: *const Symbol, rel: elf.Elf64_Rela) elf.Elf64_Rela {
429fn emitReloc(elf_file: *Elf, r_offset: u64, sym: *const Symbol, rel: elf.Elf64_Rela) elf.Elf64_Rela {
427430 const cpu_arch = elf_file.getTarget().cpu.arch;
428 const r_offset = base_offset + rel.r_offset;
429431 const r_type = rel.r_type();
430432 var r_addend = rel.r_addend;
431433 var r_sym: u32 = 0;
......@@ -467,7 +469,7 @@ pub fn writeEhFrameRelocs(elf_file: *Elf, writer: anytype) !void {
467469 for (atom_ptr.relocs(elf_file)) |rel| {
468470 const ref = zo.resolveSymbol(rel.r_sym(), elf_file);
469471 const target = elf_file.symbol(ref).?;
470 const out_rel = emitReloc(elf_file, 0, target, rel);
472 const out_rel = emitReloc(elf_file, rel.r_offset, target, rel);
471473 try writer.writeStruct(out_rel);
472474 }
473475 }
......@@ -480,8 +482,8 @@ pub fn writeEhFrameRelocs(elf_file: *Elf, writer: anytype) !void {
480482 for (cie.relocs(elf_file)) |rel| {
481483 const ref = object.resolveSymbol(rel.r_sym(), elf_file);
482484 const sym = elf_file.symbol(ref).?;
483 const offset = cie.address(elf_file) - cie.offset;
484 const out_rel = emitReloc(elf_file, offset, sym, rel);
485 const r_offset = cie.address(elf_file) + rel.r_offset - cie.offset;
486 const out_rel = emitReloc(elf_file, r_offset, sym, rel);
485487 try writer.writeStruct(out_rel);
486488 }
487489 }
......@@ -491,8 +493,8 @@ pub fn writeEhFrameRelocs(elf_file: *Elf, writer: anytype) !void {
491493 for (fde.relocs(elf_file)) |rel| {
492494 const ref = object.resolveSymbol(rel.r_sym(), elf_file);
493495 const sym = elf_file.symbol(ref).?;
494 const offset = fde.address(elf_file) - fde.offset;
495 const out_rel = emitReloc(elf_file, offset, sym, rel);
496 const r_offset = fde.address(elf_file) + rel.r_offset - fde.offset;
497 const out_rel = emitReloc(elf_file, r_offset, sym, rel);
496498 try writer.writeStruct(out_rel);
497499 }
498500 }
src/link/Elf/relocatable.zig+23-27
......@@ -302,30 +302,29 @@ fn initSections(elf_file: *Elf) !void {
302302 try msec.initOutputSection(elf_file);
303303 }
304304
305 const needs_eh_frame = if (elf_file.zigObjectPtr()) |zo|
306 zo.eh_frame_index != null
307 else for (elf_file.objects.items) |index| {
308 if (elf_file.file(index).?.object.cies.items.len > 0) break true;
309 } else false;
305 const needs_eh_frame = blk: {
306 if (elf_file.zigObjectPtr()) |zo|
307 if (zo.eh_frame_index != null) break :blk true;
308 break :blk for (elf_file.objects.items) |index| {
309 if (elf_file.file(index).?.object.cies.items.len > 0) break true;
310 } else false;
311 };
310312 if (needs_eh_frame) {
311313 if (elf_file.eh_frame_section_index == null) {
312 elf_file.eh_frame_section_index = blk: {
313 if (elf_file.zigObjectPtr()) |zo| {
314 if (zo.eh_frame_index) |idx| break :blk zo.symbol(idx).atom(elf_file).?.output_section_index;
315 }
316 break :blk try elf_file.addSection(.{
317 .name = try elf_file.insertShString(".eh_frame"),
318 .type = if (elf_file.getTarget().cpu.arch == .x86_64)
319 elf.SHT_X86_64_UNWIND
320 else
321 elf.SHT_PROGBITS,
322 .flags = elf.SHF_ALLOC,
323 .addralign = elf_file.ptrWidthBytes(),
324 .offset = std.math.maxInt(u64),
325 });
326 };
314 elf_file.eh_frame_section_index = elf_file.sectionByName(".eh_frame") orelse
315 try elf_file.addSection(.{
316 .name = try elf_file.insertShString(".eh_frame"),
317 .type = if (elf_file.getTarget().cpu.arch == .x86_64)
318 elf.SHT_X86_64_UNWIND
319 else
320 elf.SHT_PROGBITS,
321 .flags = elf.SHF_ALLOC,
322 .addralign = elf_file.ptrWidthBytes(),
323 .offset = std.math.maxInt(u64),
324 });
327325 }
328 elf_file.eh_frame_rela_section_index = try elf_file.addRelaShdr(
326 elf_file.eh_frame_rela_section_index = elf_file.sectionByName(".rela.eh_frame") orelse
327 try elf_file.addRelaShdr(
329328 try elf_file.insertShString(".rela.eh_frame"),
330329 elf_file.eh_frame_section_index.?,
331330 );
......@@ -367,6 +366,7 @@ fn updateSectionSizes(elf_file: *Elf) !void {
367366 for (slice.items(.shdr), 0..) |*shdr, shndx| {
368367 const atom_list = slice.items(.atom_list)[shndx];
369368 if (shdr.sh_type != elf.SHT_RELA) continue;
369 if (@as(u32, @intCast(shndx)) == elf_file.eh_frame_section_index) continue;
370370 for (atom_list.items) |ref| {
371371 const atom_ptr = elf_file.atom(ref) orelse continue;
372372 if (!atom_ptr.alive) continue;
......@@ -378,11 +378,7 @@ fn updateSectionSizes(elf_file: *Elf) !void {
378378 }
379379
380380 if (elf_file.eh_frame_section_index) |index| {
381 slice.items(.shdr)[index].sh_size = existing_size: {
382 const zo = elf_file.zigObjectPtr() orelse break :existing_size 0;
383 const sym = zo.symbol(zo.eh_frame_index orelse break :existing_size 0);
384 break :existing_size sym.atom(elf_file).?.size;
385 } + try eh_frame.calcEhFrameSize(elf_file);
381 slice.items(.shdr)[index].sh_size = try eh_frame.calcEhFrameSize(elf_file);
386382 }
387383 if (elf_file.eh_frame_rela_section_index) |index| {
388384 const shdr = &slice.items(.shdr)[index];
......@@ -464,8 +460,8 @@ fn writeSyntheticSections(elf_file: *Elf) !void {
464460
465461 for (slice.items(.shdr), slice.items(.atom_list), 0..) |shdr, atom_list, shndx| {
466462 if (shdr.sh_type != elf.SHT_RELA) continue;
467 if (@as(u32, @intCast(shndx)) == elf_file.eh_frame_rela_section_index) continue;
468463 if (atom_list.items.len == 0) continue;
464 if (@as(u32, @intCast(shndx)) == elf_file.eh_frame_section_index) continue;
469465
470466 const num_relocs = math.cast(usize, @divExact(shdr.sh_size, shdr.sh_entsize)) orelse
471467 return error.Overflow;