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Merge pull request #11433 from ziglang/elf-fixes

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elf: support `--strip` option and set symtab size when writing globals
This commit is contained in:
Jakub Konka
2022-04-14 20:04:29 +02:00
committed by GitHub
parent 2587474717 4d77ef25f9
commit 35171dd3db
1 changed files with 176 additions and 155 deletions
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331
src/link/Elf.zig
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@@ -100,11 +100,11 @@ offset_table: std.ArrayListUnmanaged(u64) = .{},
phdr_table_dirty: bool = false,
shdr_table_dirty: bool = false,
shstrtab_dirty: bool = false,
debug_strtab_dirty: bool = false,
offset_table_count_dirty: bool = false,
debug_strtab_dirty: bool = false,
debug_abbrev_section_dirty: bool = false,
debug_aranges_section_dirty: bool = false,
debug_info_header_dirty: bool = false,
debug_line_header_dirty: bool = false,
@@ -749,127 +749,129 @@ pub fn populateMissingMetadata(self: *Elf) !void {
try self.writeSymbol(0);
}
if (self.debug_str_section_index == null) {
self.debug_str_section_index = @intCast(u16, self.sections.items.len);
assert(self.dwarf.?.strtab.items.len == 0);
try self.sections.append(self.base.allocator, .{
.sh_name = try self.makeString(".debug_str"),
.sh_type = elf.SHT_PROGBITS,
.sh_flags = elf.SHF_MERGE | elf.SHF_STRINGS,
.sh_addr = 0,
.sh_offset = 0,
.sh_size = 0,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = 1,
.sh_entsize = 1,
});
self.debug_strtab_dirty = true;
self.shdr_table_dirty = true;
}
if (self.dwarf) |dw| {
if (self.debug_str_section_index == null) {
self.debug_str_section_index = @intCast(u16, self.sections.items.len);
assert(dw.strtab.items.len == 0);
try self.sections.append(self.base.allocator, .{
.sh_name = try self.makeString(".debug_str"),
.sh_type = elf.SHT_PROGBITS,
.sh_flags = elf.SHF_MERGE | elf.SHF_STRINGS,
.sh_addr = 0,
.sh_offset = 0,
.sh_size = 0,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = 1,
.sh_entsize = 1,
});
self.debug_strtab_dirty = true;
self.shdr_table_dirty = true;
}
if (self.debug_info_section_index == null) {
self.debug_info_section_index = @intCast(u16, self.sections.items.len);
if (self.debug_info_section_index == null) {
self.debug_info_section_index = @intCast(u16, self.sections.items.len);
const file_size_hint = 200;
const p_align = 1;
const off = self.findFreeSpace(file_size_hint, p_align);
log.debug("found .debug_info free space 0x{x} to 0x{x}", .{
off,
off + file_size_hint,
});
try self.sections.append(self.base.allocator, .{
.sh_name = try self.makeString(".debug_info"),
.sh_type = elf.SHT_PROGBITS,
.sh_flags = 0,
.sh_addr = 0,
.sh_offset = off,
.sh_size = file_size_hint,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = p_align,
.sh_entsize = 0,
});
self.shdr_table_dirty = true;
self.debug_info_header_dirty = true;
}
const file_size_hint = 200;
const p_align = 1;
const off = self.findFreeSpace(file_size_hint, p_align);
log.debug("found .debug_info free space 0x{x} to 0x{x}", .{
off,
off + file_size_hint,
});
try self.sections.append(self.base.allocator, .{
.sh_name = try self.makeString(".debug_info"),
.sh_type = elf.SHT_PROGBITS,
.sh_flags = 0,
.sh_addr = 0,
.sh_offset = off,
.sh_size = file_size_hint,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = p_align,
.sh_entsize = 0,
});
self.shdr_table_dirty = true;
self.debug_info_header_dirty = true;
}
if (self.debug_abbrev_section_index == null) {
self.debug_abbrev_section_index = @intCast(u16, self.sections.items.len);
if (self.debug_abbrev_section_index == null) {
self.debug_abbrev_section_index = @intCast(u16, self.sections.items.len);
const file_size_hint = 128;
const p_align = 1;
const off = self.findFreeSpace(file_size_hint, p_align);
log.debug("found .debug_abbrev free space 0x{x} to 0x{x}", .{
off,
off + file_size_hint,
});
try self.sections.append(self.base.allocator, .{
.sh_name = try self.makeString(".debug_abbrev"),
.sh_type = elf.SHT_PROGBITS,
.sh_flags = 0,
.sh_addr = 0,
.sh_offset = off,
.sh_size = file_size_hint,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = p_align,
.sh_entsize = 0,
});
self.shdr_table_dirty = true;
self.debug_abbrev_section_dirty = true;
}
const file_size_hint = 128;
const p_align = 1;
const off = self.findFreeSpace(file_size_hint, p_align);
log.debug("found .debug_abbrev free space 0x{x} to 0x{x}", .{
off,
off + file_size_hint,
});
try self.sections.append(self.base.allocator, .{
.sh_name = try self.makeString(".debug_abbrev"),
.sh_type = elf.SHT_PROGBITS,
.sh_flags = 0,
.sh_addr = 0,
.sh_offset = off,
.sh_size = file_size_hint,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = p_align,
.sh_entsize = 0,
});
self.shdr_table_dirty = true;
self.debug_abbrev_section_dirty = true;
}
if (self.debug_aranges_section_index == null) {
self.debug_aranges_section_index = @intCast(u16, self.sections.items.len);
if (self.debug_aranges_section_index == null) {
self.debug_aranges_section_index = @intCast(u16, self.sections.items.len);
const file_size_hint = 160;
const p_align = 16;
const off = self.findFreeSpace(file_size_hint, p_align);
log.debug("found .debug_aranges free space 0x{x} to 0x{x}", .{
off,
off + file_size_hint,
});
try self.sections.append(self.base.allocator, .{
.sh_name = try self.makeString(".debug_aranges"),
.sh_type = elf.SHT_PROGBITS,
.sh_flags = 0,
.sh_addr = 0,
.sh_offset = off,
.sh_size = file_size_hint,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = p_align,
.sh_entsize = 0,
});
self.shdr_table_dirty = true;
self.debug_aranges_section_dirty = true;
}
const file_size_hint = 160;
const p_align = 16;
const off = self.findFreeSpace(file_size_hint, p_align);
log.debug("found .debug_aranges free space 0x{x} to 0x{x}", .{
off,
off + file_size_hint,
});
try self.sections.append(self.base.allocator, .{
.sh_name = try self.makeString(".debug_aranges"),
.sh_type = elf.SHT_PROGBITS,
.sh_flags = 0,
.sh_addr = 0,
.sh_offset = off,
.sh_size = file_size_hint,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = p_align,
.sh_entsize = 0,
});
self.shdr_table_dirty = true;
self.debug_aranges_section_dirty = true;
}
if (self.debug_line_section_index == null) {
self.debug_line_section_index = @intCast(u16, self.sections.items.len);
if (self.debug_line_section_index == null) {
self.debug_line_section_index = @intCast(u16, self.sections.items.len);
const file_size_hint = 250;
const p_align = 1;
const off = self.findFreeSpace(file_size_hint, p_align);
log.debug("found .debug_line free space 0x{x} to 0x{x}", .{
off,
off + file_size_hint,
});
try self.sections.append(self.base.allocator, .{
.sh_name = try self.makeString(".debug_line"),
.sh_type = elf.SHT_PROGBITS,
.sh_flags = 0,
.sh_addr = 0,
.sh_offset = off,
.sh_size = file_size_hint,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = p_align,
.sh_entsize = 0,
});
self.shdr_table_dirty = true;
self.debug_line_header_dirty = true;
const file_size_hint = 250;
const p_align = 1;
const off = self.findFreeSpace(file_size_hint, p_align);
log.debug("found .debug_line free space 0x{x} to 0x{x}", .{
off,
off + file_size_hint,
});
try self.sections.append(self.base.allocator, .{
.sh_name = try self.makeString(".debug_line"),
.sh_type = elf.SHT_PROGBITS,
.sh_flags = 0,
.sh_addr = 0,
.sh_offset = off,
.sh_size = file_size_hint,
.sh_link = 0,
.sh_info = 0,
.sh_addralign = p_align,
.sh_entsize = 0,
});
self.shdr_table_dirty = true;
self.debug_line_header_dirty = true;
}
}
const shsize: u64 = switch (self.ptr_width) {
@@ -1001,40 +1003,42 @@ pub fn flushModule(self: *Elf, comp: *Compilation) !void {
// mixing local and global symbols within a symbol table.
try self.writeAllGlobalSymbols();
if (self.debug_abbrev_section_dirty) {
try self.dwarf.?.writeDbgAbbrev(&self.base);
if (!self.shdr_table_dirty) {
// Then it won't get written with the others and we need to do it.
try self.writeSectHeader(self.debug_abbrev_section_index.?);
if (self.dwarf) |*dw| {
if (self.debug_abbrev_section_dirty) {
try dw.writeDbgAbbrev(&self.base);
if (!self.shdr_table_dirty) {
// Then it won't get written with the others and we need to do it.
try self.writeSectHeader(self.debug_abbrev_section_index.?);
}
self.debug_abbrev_section_dirty = false;
}
self.debug_abbrev_section_dirty = false;
}
if (self.debug_info_header_dirty) {
// Currently only one compilation unit is supported, so the address range is simply
// identical to the main program header virtual address and memory size.
const text_phdr = &self.program_headers.items[self.phdr_load_re_index.?];
const low_pc = text_phdr.p_vaddr;
const high_pc = text_phdr.p_vaddr + text_phdr.p_memsz;
try self.dwarf.?.writeDbgInfoHeader(&self.base, module, low_pc, high_pc);
self.debug_info_header_dirty = false;
}
if (self.debug_aranges_section_dirty) {
// Currently only one compilation unit is supported, so the address range is simply
// identical to the main program header virtual address and memory size.
const text_phdr = &self.program_headers.items[self.phdr_load_re_index.?];
try self.dwarf.?.writeDbgAranges(&self.base, text_phdr.p_vaddr, text_phdr.p_memsz);
if (!self.shdr_table_dirty) {
// Then it won't get written with the others and we need to do it.
try self.writeSectHeader(self.debug_aranges_section_index.?);
if (self.debug_info_header_dirty) {
// Currently only one compilation unit is supported, so the address range is simply
// identical to the main program header virtual address and memory size.
const text_phdr = &self.program_headers.items[self.phdr_load_re_index.?];
const low_pc = text_phdr.p_vaddr;
const high_pc = text_phdr.p_vaddr + text_phdr.p_memsz;
try dw.writeDbgInfoHeader(&self.base, module, low_pc, high_pc);
self.debug_info_header_dirty = false;
}
self.debug_aranges_section_dirty = false;
}
if (self.debug_line_header_dirty) {
try self.dwarf.?.writeDbgLineHeader(&self.base, module);
self.debug_line_header_dirty = false;
if (self.debug_aranges_section_dirty) {
// Currently only one compilation unit is supported, so the address range is simply
// identical to the main program header virtual address and memory size.
const text_phdr = &self.program_headers.items[self.phdr_load_re_index.?];
try dw.writeDbgAranges(&self.base, text_phdr.p_vaddr, text_phdr.p_memsz);
if (!self.shdr_table_dirty) {
// Then it won't get written with the others and we need to do it.
try self.writeSectHeader(self.debug_aranges_section_index.?);
}
self.debug_aranges_section_dirty = false;
}
if (self.debug_line_header_dirty) {
try dw.writeDbgLineHeader(&self.base, module);
self.debug_line_header_dirty = false;
}
}
if (self.phdr_table_dirty) {
@@ -1105,9 +1109,8 @@ pub fn flushModule(self: *Elf, comp: *Compilation) !void {
}
}
{
if (self.dwarf) |dwarf| {
const debug_strtab_sect = &self.sections.items[self.debug_str_section_index.?];
const dwarf = self.dwarf.?;
if (self.debug_strtab_dirty or dwarf.strtab.items.len != debug_strtab_sect.sh_size) {
const allocated_size = self.allocatedSize(debug_strtab_sect.sh_offset);
const needed_size = dwarf.strtab.items.len;
@@ -2105,14 +2108,16 @@ fn allocateTextBlock(self: *Elf, text_block: *TextBlock, new_block_size: u64, al
phdr.p_memsz = needed_size;
phdr.p_filesz = needed_size;
// The .debug_info section has `low_pc` and `high_pc` values which is the virtual address
// range of the compilation unit. When we expand the text section, this range changes,
// so the DW_TAG.compile_unit tag of the .debug_info section becomes dirty.
self.debug_info_header_dirty = true;
// This becomes dirty for the same reason. We could potentially make this more
// fine-grained with the addition of support for more compilation units. It is planned to
// model each package as a different compilation unit.
self.debug_aranges_section_dirty = true;
if (self.dwarf) |_| {
// The .debug_info section has `low_pc` and `high_pc` values which is the virtual address
// range of the compilation unit. When we expand the text section, this range changes,
// so the DW_TAG.compile_unit tag of the .debug_info section becomes dirty.
self.debug_info_header_dirty = true;
// This becomes dirty for the same reason. We could potentially make this more
// fine-grained with the addition of support for more compilation units. It is planned to
// model each package as a different compilation unit.
self.debug_aranges_section_dirty = true;
}
self.phdr_table_dirty = true; // TODO look into making only the one program header dirty
self.shdr_table_dirty = true; // TODO look into making only the one section dirty
@@ -2794,6 +2799,22 @@ fn writeAllGlobalSymbols(self: *Elf) !void {
.p32 => @sizeOf(elf.Elf32_Sym),
.p64 => @sizeOf(elf.Elf64_Sym),
};
const sym_align: u16 = switch (self.ptr_width) {
.p32 => @alignOf(elf.Elf32_Sym),
.p64 => @alignOf(elf.Elf64_Sym),
};
const needed_size = (self.local_symbols.items.len + self.global_symbols.items.len) * sym_size;
if (needed_size > self.allocatedSize(syms_sect.sh_offset)) {
// Move all the symbols to a new file location.
const new_offset = self.findFreeSpace(needed_size, sym_align);
const existing_size = @as(u64, syms_sect.sh_info) * sym_size;
const amt = try self.base.file.?.copyRangeAll(syms_sect.sh_offset, self.base.file.?, new_offset, existing_size);
if (amt != existing_size) return error.InputOutput;
syms_sect.sh_offset = new_offset;
}
syms_sect.sh_size = needed_size; // anticipating adding the global symbols later
self.shdr_table_dirty = true; // TODO look into only writing one section
const foreign_endian = self.base.options.target.cpu.arch.endian() != builtin.cpu.arch.endian();
const global_syms_off = syms_sect.sh_offset + self.local_symbols.items.len * sym_size;
switch (self.ptr_width) {