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https://github.com/ziglang/zig.git
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elf: allocate linker defined symbols
This commit is contained in:
Jakub Konka
parent
1c3fd16c37
commit
a3ce011408
197
src/link/Elf.zig
197
src/link/Elf.zig
@ -47,8 +47,13 @@ got: GotSection = .{},
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text_section_index: ?u16 = null,
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rodata_section_index: ?u16 = null,
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got_section_index: ?u16 = null,
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data_section_index: ?u16 = null,
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dynamic_section_index: ?u16 = null,
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got_section_index: ?u16 = null,
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got_plt_section_index: ?u16 = null,
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plt_section_index: ?u16 = null,
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eh_frame_hdr_section_index: ?u16 = null,
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rela_dyn_section_index: ?u16 = null,
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debug_info_section_index: ?u16 = null,
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debug_abbrev_section_index: ?u16 = null,
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debug_str_section_index: ?u16 = null,
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@ -74,6 +79,7 @@ gnu_eh_frame_hdr_index: ?Symbol.Index = null,
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dso_handle_index: ?Symbol.Index = null,
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rela_iplt_start_index: ?Symbol.Index = null,
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rela_iplt_end_index: ?Symbol.Index = null,
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start_stop_indexes: std.ArrayListUnmanaged(u32) = .{},
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symbols: std.ArrayListUnmanaged(Symbol) = .{},
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symbols_extra: std.ArrayListUnmanaged(u32) = .{},
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@ -264,6 +270,7 @@ pub fn deinit(self: *Elf) void {
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self.got.deinit(gpa);
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self.resolver.deinit(gpa);
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self.unresolved.deinit(gpa);
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self.start_stop_indexes.deinit(gpa);
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{
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var it = self.decls.iterator();
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@ -385,6 +392,7 @@ pub fn populateMissingMetadata(self: *Elf) !void {
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.p64 => false,
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};
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const ptr_size: u8 = self.ptrWidthBytes();
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const image_base = self.calcImageBase();
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if (self.phdr_table_index == null) {
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self.phdr_table_index = @as(u16, @intCast(self.phdrs.items.len));
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@ -396,8 +404,8 @@ pub fn populateMissingMetadata(self: *Elf) !void {
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.p_type = elf.PT_PHDR,
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.p_offset = 0,
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.p_filesz = 0,
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.p_vaddr = 0,
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.p_paddr = 0,
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.p_vaddr = image_base,
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.p_paddr = image_base,
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.p_memsz = 0,
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.p_align = p_align,
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.p_flags = elf.PF_R,
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@ -408,16 +416,14 @@ pub fn populateMissingMetadata(self: *Elf) !void {
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if (self.phdr_table_load_index == null) {
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self.phdr_table_load_index = @as(u16, @intCast(self.phdrs.items.len));
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// TODO Same as for GOT
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const phdr_addr: u64 = if (self.base.options.target.ptrBitWidth() >= 32) 0x1000000 else 0x1000;
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const p_align = self.page_size;
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try self.phdrs.append(gpa, .{
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.p_type = elf.PT_LOAD,
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.p_offset = 0,
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.p_filesz = 0,
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.p_vaddr = phdr_addr,
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.p_paddr = phdr_addr,
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.p_vaddr = image_base,
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.p_paddr = image_base,
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.p_memsz = 0,
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.p_align = p_align,
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.p_align = self.page_size,
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.p_flags = elf.PF_R,
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});
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self.phdr_table_dirty = true;
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@ -429,7 +435,7 @@ pub fn populateMissingMetadata(self: *Elf) !void {
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const p_align = self.page_size;
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const off = self.findFreeSpace(file_size, p_align);
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log.debug("found PT_LOAD RE free space 0x{x} to 0x{x}", .{ off, off + file_size });
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const entry_addr: u64 = self.entry_addr orelse if (self.base.options.target.cpu.arch == .spu_2) @as(u64, 0) else default_entry_addr;
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const entry_addr = self.defaultEntryAddress();
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try self.phdrs.append(gpa, .{
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.p_type = elf.PT_LOAD,
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.p_offset = off,
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@ -1055,6 +1061,8 @@ pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node
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try self.addLinkerDefinedSymbols();
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self.allocateLinkerDefinedSymbols();
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// Beyond this point, everything has been allocated a virtual address and we can resolve
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// the relocations.
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{
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@ -2764,6 +2772,129 @@ fn addLinkerDefinedSymbols(self: *Elf) !void {
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linker_defined.resolveSymbols(self);
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}
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fn allocateLinkerDefinedSymbols(self: *Elf) void {
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// _DYNAMIC
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if (self.dynamic_section_index) |shndx| {
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const shdr = self.sections.items(.shdr)[shndx];
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const symbol_ptr = self.symbol(self.dynamic_index.?);
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symbol_ptr.value = shdr.sh_addr;
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symbol_ptr.output_section_index = shndx;
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}
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// __ehdr_start
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{
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const symbol_ptr = self.symbol(self.ehdr_start_index.?);
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symbol_ptr.value = self.calcImageBase();
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symbol_ptr.output_section_index = 1;
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}
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// __init_array_start, __init_array_end
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if (self.sectionByName(".init_array")) |shndx| {
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const start_sym = self.symbol(self.init_array_start_index.?);
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const end_sym = self.symbol(self.init_array_end_index.?);
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const shdr = &self.sections.items(.shdr)[shndx];
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start_sym.output_section_index = shndx;
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start_sym.value = shdr.sh_addr;
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end_sym.output_section_index = shndx;
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end_sym.value = shdr.sh_addr + shdr.sh_size;
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}
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// __fini_array_start, __fini_array_end
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if (self.sectionByName(".fini_array")) |shndx| {
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const start_sym = self.symbol(self.fini_array_start_index.?);
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const end_sym = self.symbol(self.fini_array_end_index.?);
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const shdr = &self.sections.items(.shdr)[shndx];
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start_sym.output_section_index = shndx;
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start_sym.value = shdr.sh_addr;
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end_sym.output_section_index = shndx;
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end_sym.value = shdr.sh_addr + shdr.sh_size;
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}
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// __preinit_array_start, __preinit_array_end
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if (self.sectionByName(".preinit_array")) |shndx| {
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const start_sym = self.symbol(self.preinit_array_start_index.?);
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const end_sym = self.symbol(self.preinit_array_end_index.?);
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const shdr = &self.sections.items(.shdr)[shndx];
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start_sym.output_section_index = shndx;
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start_sym.value = shdr.sh_addr;
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end_sym.output_section_index = shndx;
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end_sym.value = shdr.sh_addr + shdr.sh_size;
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}
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// _GLOBAL_OFFSET_TABLE_
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if (self.got_plt_section_index) |shndx| {
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const shdr = &self.sections.items(.shdr)[shndx];
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const symbol_ptr = self.symbol(self.got_index.?);
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symbol_ptr.value = shdr.sh_addr;
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symbol_ptr.output_section_index = shndx;
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}
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// _PROCEDURE_LINKAGE_TABLE_
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if (self.plt_section_index) |shndx| {
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const shdr = &self.sections.items(.shdr)[shndx];
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const symbol_ptr = self.symbol(self.plt_index.?);
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symbol_ptr.value = shdr.sh_addr;
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symbol_ptr.output_section_index = shndx;
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}
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// __dso_handle
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if (self.dso_handle_index) |index| {
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const shdr = &self.sections.items(.shdr)[1];
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const symbol_ptr = self.symbol(index);
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symbol_ptr.value = shdr.sh_addr;
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symbol_ptr.output_section_index = 0;
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}
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// __GNU_EH_FRAME_HDR
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if (self.eh_frame_hdr_section_index) |shndx| {
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const shdr = &self.sections.items(.shdr)[shndx];
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const symbol_ptr = self.symbol(self.gnu_eh_frame_hdr_index.?);
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symbol_ptr.value = shdr.sh_addr;
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symbol_ptr.output_section_index = shndx;
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}
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// __rela_iplt_start, __rela_iplt_end
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if (self.rela_dyn_section_index) |shndx| blk: {
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if (self.base.options.link_mode != .Static or self.base.options.pie) break :blk;
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const shdr = &self.sections.items(.shdr)[shndx];
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const end_addr = shdr.sh_addr + shdr.sh_size;
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const start_addr = end_addr - self.calcNumIRelativeRelocs() * @sizeOf(elf.Elf64_Rela);
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const start_sym = self.symbol(self.rela_iplt_start_index.?);
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const end_sym = self.symbol(self.rela_iplt_end_index.?);
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start_sym.value = start_addr;
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start_sym.output_section_index = shndx;
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end_sym.value = end_addr;
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end_sym.output_section_index = shndx;
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}
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// _end
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{
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const end_symbol = self.symbol(self.end_index.?);
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for (self.sections.items(.shdr), 0..) |shdr, shndx| {
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if (shdr.sh_flags & elf.SHF_ALLOC != 0) {
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end_symbol.value = shdr.sh_addr + shdr.sh_size;
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end_symbol.output_section_index = @intCast(shndx);
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}
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}
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}
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// __start_*, __stop_*
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{
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var index: usize = 0;
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while (index < self.start_stop_indexes.items.len) : (index += 2) {
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const start = self.symbol(self.start_stop_indexes.items[index]);
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const name = start.name(self);
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const stop = self.symbol(self.start_stop_indexes.items[index + 1]);
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const shndx = self.sectionByName(name["__start_".len..]).?;
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const shdr = self.sections.items(.shdr)[shndx];
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start.value = shdr.sh_addr;
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start.output_section_index = shndx;
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stop.value = shdr.sh_addr + shdr.sh_size;
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stop.output_section_index = shndx;
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}
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}
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}
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fn updateSymtabSize(self: *Elf) !void {
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var sizes = SymtabSize{};
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@ -2774,17 +2905,17 @@ fn updateSymtabSize(self: *Elf) !void {
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sizes.nglobals += zig_module.output_symtab_size.nglobals;
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}
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if (self.got_section_index) |_| {
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self.got.updateSymtabSize(self);
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sizes.nlocals += self.got.output_symtab_size.nlocals;
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}
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if (self.linker_defined_index) |index| {
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const linker_defined = self.file(index).?.linker_defined;
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linker_defined.updateSymtabSize(self);
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sizes.nlocals += linker_defined.output_symtab_size.nlocals;
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}
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if (self.got_section_index) |_| {
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self.got.updateSymtabSize(self);
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sizes.nlocals += self.got.output_symtab_size.nlocals;
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}
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const shdr = &self.sections.items(.shdr)[self.symtab_section_index.?];
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shdr.sh_info = sizes.nlocals + 1;
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self.markDirty(self.symtab_section_index.?, null);
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@ -2829,17 +2960,17 @@ fn writeSymtab(self: *Elf) !void {
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ctx.iglobal += zig_module.output_symtab_size.nglobals;
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}
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if (self.got_section_index) |_| {
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try self.got.writeSymtab(self, ctx);
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ctx.ilocal += self.got.output_symtab_size.nlocals;
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}
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if (self.linker_defined_index) |index| {
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const linker_defined = self.file(index).?.linker_defined;
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linker_defined.writeSymtab(self, ctx);
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ctx.ilocal += linker_defined.output_symtab_size.nlocals;
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}
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if (self.got_section_index) |_| {
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try self.got.writeSymtab(self, ctx);
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ctx.ilocal += self.got.output_symtab_size.nlocals;
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}
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const foreign_endian = self.base.options.target.cpu.arch.endian() != builtin.cpu.arch.endian();
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switch (self.ptr_width) {
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.p32 => {
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@ -3179,6 +3310,34 @@ const CsuObjects = struct {
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}
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};
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pub fn calcImageBase(self: Elf) u64 {
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if (self.base.options.pic) return 0; // TODO flag an error if PIC and image_base_override
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return self.base.options.image_base_override orelse switch (self.ptr_width) {
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.p32 => 0x1000,
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.p64 => 0x1000000,
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};
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}
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pub fn defaultEntryAddress(self: Elf) u64 {
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if (self.entry_addr) |addr| return addr;
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return switch (self.base.options.target.cpu.arch) {
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.spu_2 => 0,
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else => default_entry_addr,
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};
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}
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pub fn sectionByName(self: *Elf, name: [:0]const u8) ?u16 {
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for (self.sections.items(.shdr), 0..) |shdr, i| {
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const this_name = self.shstrtab.getAssumeExists(shdr.sh_name);
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if (mem.eql(u8, this_name, name)) return @as(u16, @intCast(i));
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} else return null;
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}
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pub fn calcNumIRelativeRelocs(self: *Elf) u64 {
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_ = self;
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unreachable; // TODO
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}
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pub fn atom(self: *Elf, atom_index: Atom.Index) ?*Atom {
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if (atom_index == 0) return null;
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assert(atom_index < self.atoms.items.len);
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