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elf: allocate .tdata and .tbss sections

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This commit is contained in:
Jakub Konka 2023-09-28 13:29:04 +02:00
parent 22127a8792
commit a63ce5a37c
1 changed files with 56 additions and 10 deletions
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66
src/link/Elf.zig
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@ -46,7 +46,9 @@ phdr_load_zerofill_index: ?u16 = null,
/// The index into the program headers of the PT_TLS program header.
phdr_tls_index: ?u16 = null,
/// The index into the program headers of a PT_LOAD program header with TLS data.
phdr_load_tls_index: ?u16 = null,
phdr_load_tls_data_index: ?u16 = null,
/// The index into the program headers of a PT_LOAD program header with TLS zerofill data.
phdr_load_tls_zerofill_index: ?u16 = null,
entry_addr: ?u64 = null,
page_size: u32,
@ -499,7 +501,7 @@ pub fn allocateAllocSection(self: *Elf, opts: AllocateAllocSectionOpts) error{Ou
.sh_flags = opts.flags,
.sh_addr = phdr.p_vaddr,
.sh_offset = phdr.p_offset,
.sh_size = phdr.p_filesz,
.sh_size = phdr.p_memsz,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = opts.alignment,
@ -631,24 +633,37 @@ pub fn populateMissingMetadata(self: *Elf) !void {
}
if (!self.base.options.single_threaded) {
if (self.phdr_load_tls_index == null) {
if (self.phdr_load_tls_data_index == null) {
const alignment = if (is_linux) self.page_size else @as(u16, ptr_size);
self.phdr_load_tls_index = try self.allocateSegment(.{
self.phdr_load_tls_data_index = try self.allocateSegment(.{
.size = 1024,
.alignment = alignment,
.flags = elf.PF_R | elf.PF_W,
});
}
if (self.phdr_load_tls_zerofill_index == null) {
const alignment = if (is_linux) self.page_size else @as(u16, ptr_size);
self.phdr_load_tls_zerofill_index = try self.allocateSegment(.{
.size = 0,
.alignment = alignment,
.flags = elf.PF_R | elf.PF_W,
});
const phdr = &self.phdrs.items[self.phdr_load_tls_zerofill_index.?];
phdr.p_offset = self.phdrs.items[self.phdr_load_tls_data_index.?].p_offset; // .tbss overlaps .tdata
phdr.p_memsz = 1024;
}
if (self.phdr_tls_index == null) {
const phdr = &self.phdrs.items[self.phdr_load_tls_index.?];
const phdr_tdata = &self.phdrs.items[self.phdr_load_tls_data_index.?];
const phdr_tbss = &self.phdrs.items[self.phdr_load_tls_zerofill_index.?];
try self.phdrs.append(gpa, .{
.p_type = elf.PT_TLS,
.p_offset = phdr.p_offset,
.p_vaddr = phdr.p_vaddr,
.p_paddr = phdr.p_paddr,
.p_filesz = phdr.p_filesz,
.p_memsz = phdr.p_memsz,
.p_offset = phdr_tdata.p_offset,
.p_vaddr = phdr_tdata.p_vaddr,
.p_paddr = phdr_tdata.p_paddr,
.p_filesz = phdr_tdata.p_filesz,
.p_memsz = phdr_tbss.p_vaddr + phdr_tbss.p_memsz - phdr_tdata.p_vaddr,
.p_align = ptr_size,
.p_flags = elf.PF_R,
});
@ -724,6 +739,31 @@ pub fn populateMissingMetadata(self: *Elf) !void {
try self.last_atom_and_free_list_table.putNoClobber(gpa, self.bss_section_index.?, .{});
}
if (self.phdr_load_tls_data_index) |phdr_index| {
if (self.tdata_section_index == null) {
self.tdata_section_index = try self.allocateAllocSection(.{
.name = ".tdata",
.phdr_index = phdr_index,
.alignment = ptr_size,
.flags = elf.SHF_ALLOC | elf.SHF_WRITE | elf.SHF_TLS,
});
try self.last_atom_and_free_list_table.putNoClobber(gpa, self.tdata_section_index.?, .{});
}
}
if (self.phdr_load_tls_zerofill_index) |phdr_index| {
if (self.tbss_section_index == null) {
self.tbss_section_index = try self.allocateAllocSection(.{
.name = ".tbss",
.phdr_index = phdr_index,
.alignment = ptr_size,
.flags = elf.SHF_ALLOC | elf.SHF_WRITE | elf.SHF_TLS,
.type = elf.SHT_NOBITS,
});
try self.last_atom_and_free_list_table.putNoClobber(gpa, self.tbss_section_index.?, .{});
}
}
if (self.symtab_section_index == null) {
const min_align: u16 = if (small_ptr) @alignOf(elf.Elf32_Sym) else @alignOf(elf.Elf64_Sym);
const each_size: u64 = if (small_ptr) @sizeOf(elf.Elf32_Sym) else @sizeOf(elf.Elf64_Sym);
@ -1295,6 +1335,12 @@ pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node
self.phdrs.items[bss_phndx].p_offset = self.phdrs.items[data_phndx].p_offset;
}
// Same treatment for .tbss section.
if (self.tdata_section_index) |tdata_shndx| blk: {
const tbss_shndx = self.tbss_section_index orelse break :blk;
self.shdrs.items[tbss_shndx].sh_offset = self.shdrs.items[tdata_shndx].sh_offset;
}
// Dump the state for easy debugging.
// State can be dumped via `--debug-log link_state`.
if (build_options.enable_logging) {