commit 0aa24ac2e3c122ad16d54d640c11f2de6eb2299a (tree)
parent 9a15c3e1a1dc01d04c976ffbdec46b206455634e
Author: Jakub Konka <kubkon@jakubkonka.com>
Date: Mon, 30 Sep 2024 22:09:44 +0200
elf: move sections in segments that need moving only
Diffstat:
2 files changed, 53 insertions(+), 82 deletions(-)
diff --git a/src/link/Elf.zig b/src/link/Elf.zig
@@ -570,8 +570,6 @@ pub fn growAllocSection(self: *Elf, shdr_index: u32, needed_size: u64, min_align
const slice = self.sections.slice();
const shdr = &slice.items(.shdr)[shdr_index];
assert(shdr.sh_flags & elf.SHF_ALLOC != 0);
- const phndx = slice.items(.phndx)[shdr_index];
- const maybe_phdr = if (phndx) |ndx| &self.phdrs.items[ndx] else null;
log.debug("allocated size {x} of {s}, needed size {x}", .{
self.allocatedSize(shdr.sh_offset),
@@ -598,11 +596,9 @@ pub fn growAllocSection(self: *Elf, shdr_index: u32, needed_size: u64, min_align
if (amt != existing_size) return error.InputOutput;
shdr.sh_offset = new_offset;
- if (maybe_phdr) |phdr| phdr.p_offset = new_offset;
} else if (shdr.sh_offset + allocated_size == std.math.maxInt(u64)) {
try self.base.file.?.setEndPos(shdr.sh_offset + needed_size);
}
- if (maybe_phdr) |phdr| phdr.p_filesz = needed_size;
}
shdr.sh_size = needed_size;
self.markDirty(shdr_index);
@@ -3890,57 +3886,70 @@ pub fn allocateAllocSections(self: *Elf) !void {
}
const first = slice.items(.shdr)[cover.items[0]];
- var new_offset = try self.findFreeSpace(filesz, @"align");
const phndx = self.getPhdr(.{ .type = elf.PT_LOAD, .flags = shdrToPhdrFlags(first.sh_flags) }).?;
const phdr = &self.phdrs.items[phndx];
- phdr.p_offset = new_offset;
- phdr.p_vaddr = first.sh_addr;
- phdr.p_paddr = first.sh_addr;
- phdr.p_memsz = memsz;
- phdr.p_filesz = filesz;
- phdr.p_align = @"align";
-
- for (cover.items) |shndx| {
- const shdr = &slice.items(.shdr)[shndx];
- slice.items(.phndx)[shndx] = phndx;
- if (shdr.sh_type == elf.SHT_NOBITS) {
- shdr.sh_offset = 0;
- continue;
- }
- new_offset = alignment.@"align"(shndx, shdr.sh_addralign, new_offset);
+ const allocated_size = self.allocatedSize(phdr.p_offset);
+ if (filesz > allocated_size) {
+ const old_offset = phdr.p_offset;
+ phdr.p_offset = 0;
+ var new_offset = try self.findFreeSpace(filesz, @"align");
+ phdr.p_offset = new_offset;
+
+ log.debug("moving phdr({d}) from 0x{x} to 0x{x}", .{ phndx, old_offset, new_offset });
+
+ for (cover.items) |shndx| {
+ const shdr = &slice.items(.shdr)[shndx];
+ slice.items(.phndx)[shndx] = phndx;
+ if (shdr.sh_type == elf.SHT_NOBITS) {
+ shdr.sh_offset = 0;
+ continue;
+ }
+ new_offset = alignment.@"align"(shndx, shdr.sh_addralign, new_offset);
- if (self.zigObjectPtr()) |zo| blk: {
- const existing_size = for ([_]?Symbol.Index{
- zo.text_index,
- zo.rodata_index,
- zo.data_relro_index,
- zo.data_index,
- zo.tdata_index,
- zo.eh_frame_index,
- }) |maybe_sym_index| {
- const sect_sym_index = maybe_sym_index orelse continue;
- const sect_atom_ptr = zo.symbol(sect_sym_index).atom(self).?;
- if (sect_atom_ptr.output_section_index != shndx) continue;
- break sect_atom_ptr.size;
- } else break :blk;
log.debug("moving {s} from 0x{x} to 0x{x}", .{
self.getShString(shdr.sh_name),
shdr.sh_offset,
new_offset,
});
- const amt = try self.base.file.?.copyRangeAll(
- shdr.sh_offset,
- self.base.file.?,
- new_offset,
- existing_size,
- );
- if (amt != existing_size) return error.InputOutput;
- }
- shdr.sh_offset = new_offset;
- new_offset += shdr.sh_size;
+ if (shdr.sh_offset > 0) {
+ // Get size actually commited to the output file.
+ const existing_size = if (self.zigObjectPtr()) |zo| for ([_]?Symbol.Index{
+ zo.text_index,
+ zo.rodata_index,
+ zo.data_relro_index,
+ zo.data_index,
+ zo.tdata_index,
+ zo.eh_frame_index,
+ }) |maybe_sym_index| {
+ const sect_sym_index = maybe_sym_index orelse continue;
+ const sect_atom_ptr = zo.symbol(sect_sym_index).atom(self).?;
+ if (sect_atom_ptr.output_section_index != shndx) continue;
+ break sect_atom_ptr.size;
+ } else 0 else 0 + if (!slice.items(.atom_list_2)[shndx].dirty)
+ slice.items(.atom_list_2)[shndx].size
+ else
+ 0;
+ const amt = try self.base.file.?.copyRangeAll(
+ shdr.sh_offset,
+ self.base.file.?,
+ new_offset,
+ existing_size,
+ );
+ if (amt != existing_size) return error.InputOutput;
+ }
+
+ shdr.sh_offset = new_offset;
+ new_offset += shdr.sh_size;
+ }
}
+ phdr.p_vaddr = first.sh_addr;
+ phdr.p_paddr = first.sh_addr;
+ phdr.p_memsz = memsz;
+ phdr.p_filesz = filesz;
+ phdr.p_align = @"align";
+
addr = mem.alignForward(u64, addr, self.page_size);
}
}
diff --git a/src/link/Elf/ZigObject.zig b/src/link/Elf/ZigObject.zig
@@ -336,8 +336,6 @@ pub fn flushModule(self: *ZigObject, elf_file: *Elf, tid: Zcu.PerThread.Id) !voi
const atom_ptr = self.atom(sym.ref.index).?;
if (!atom_ptr.alive) continue;
- log.debug("parsing relocs in {s}", .{sym.name(elf_file)});
-
const relocs = &self.relocs.items[atom_ptr.relocsShndx().?];
for (sect.units.items) |*unit| {
try relocs.ensureUnusedCapacity(gpa, unit.cross_unit_relocs.items.len +
@@ -350,12 +348,6 @@ pub fn flushModule(self: *ZigObject, elf_file: *Elf, tid: Zcu.PerThread.Id) !voi
else
0));
const r_type = relocation.dwarf.crossSectionRelocType(dwarf.format, cpu_arch);
- log.debug(" {s} <- r_off={x}, r_add={x}, r_type={}", .{
- self.symbol(sym_index).name(elf_file),
- r_offset,
- r_addend,
- relocation.fmtRelocType(r_type, cpu_arch),
- });
atom_ptr.addRelocAssumeCapacity(.{
.r_offset = r_offset,
.r_addend = r_addend,
@@ -384,12 +376,6 @@ pub fn flushModule(self: *ZigObject, elf_file: *Elf, tid: Zcu.PerThread.Id) !voi
else
0));
const r_type = relocation.dwarf.crossSectionRelocType(dwarf.format, cpu_arch);
- log.debug(" {s} <- r_off={x}, r_add={x}, r_type={}", .{
- self.symbol(target_sym_index).name(elf_file),
- r_offset,
- r_addend,
- relocation.fmtRelocType(r_type, cpu_arch),
- });
atom_ptr.addRelocAssumeCapacity(.{
.r_offset = r_offset,
.r_addend = r_addend,
@@ -410,12 +396,6 @@ pub fn flushModule(self: *ZigObject, elf_file: *Elf, tid: Zcu.PerThread.Id) !voi
else
0));
const r_type = relocation.dwarf.crossSectionRelocType(dwarf.format, cpu_arch);
- log.debug(" {s} <- r_off={x}, r_add={x}, r_type={}", .{
- self.symbol(sym_index).name(elf_file),
- r_offset,
- r_addend,
- relocation.fmtRelocType(r_type, cpu_arch),
- });
atom_ptr.addRelocAssumeCapacity(.{
.r_offset = r_offset,
.r_addend = r_addend,
@@ -430,12 +410,6 @@ pub fn flushModule(self: *ZigObject, elf_file: *Elf, tid: Zcu.PerThread.Id) !voi
else
0));
const r_type = relocation.dwarf.crossSectionRelocType(dwarf.format, cpu_arch);
- log.debug(" {s} <- r_off={x}, r_add={x}, r_type={}", .{
- self.symbol(sym_index).name(elf_file),
- r_offset,
- r_addend,
- relocation.fmtRelocType(r_type, cpu_arch),
- });
atom_ptr.addRelocAssumeCapacity(.{
.r_offset = r_offset,
.r_addend = r_addend,
@@ -464,12 +438,6 @@ pub fn flushModule(self: *ZigObject, elf_file: *Elf, tid: Zcu.PerThread.Id) !voi
else
0));
const r_type = relocation.dwarf.crossSectionRelocType(dwarf.format, cpu_arch);
- log.debug(" {s} <- r_off={x}, r_add={x}, r_type={}", .{
- self.symbol(target_sym_index).name(elf_file),
- r_offset,
- r_addend,
- relocation.fmtRelocType(r_type, cpu_arch),
- });
atom_ptr.addRelocAssumeCapacity(.{
.r_offset = r_offset,
.r_addend = r_addend,
@@ -481,12 +449,6 @@ pub fn flushModule(self: *ZigObject, elf_file: *Elf, tid: Zcu.PerThread.Id) !voi
const r_offset = entry_off + reloc.source_off;
const r_addend: i64 = @intCast(reloc.target_off);
const r_type = relocation.dwarf.externalRelocType(target_sym.*, sect_index, dwarf.address_size, cpu_arch);
- log.debug(" {s} <- r_off={x}, r_add={x}, r_type={}", .{
- target_sym.name(elf_file),
- r_offset,
- r_addend,
- relocation.fmtRelocType(r_type, cpu_arch),
- });
atom_ptr.addRelocAssumeCapacity(.{
.r_offset = r_offset,
.r_addend = r_addend,
