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elf: allocate .data.rel.ro and .rodata in ZigObject similarly to .eh_frame

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This commit is contained in:
Jakub Konka
2024-08-29 20:56:12 +02:00
parent 0b92404ddf
commit 848535535d
2 changed files with 62 additions and 48 deletions
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9
src/link/Elf.zig
View File

@@ -57,8 +57,6 @@ phdrs: std.ArrayListUnmanaged(elf.Elf64_Phdr) = .{},
/// Tracked loadable segments during incremental linking.
/// The index into the program headers of a PT_LOAD program header with Read and Execute flags
phdr_zig_load_re_index: ?u16 = null,
/// The index into the program headers of a PT_LOAD program header with Read flag
phdr_zig_load_ro_index: ?u16 = null,
/// Special program headers
/// PT_PHDR
@@ -123,7 +121,6 @@ comdat_group_sections: std.ArrayListUnmanaged(ComdatGroupSection) = .{},
/// Tracked section headers with incremental updates to Zig object.
/// .rela.* sections are only used when emitting a relocatable object file.
zig_text_section_index: ?u32 = null,
zig_data_rel_ro_section_index: ?u32 = null,
debug_info_section_index: ?u32 = null,
debug_abbrev_section_index: ?u32 = null,
@@ -3360,7 +3357,6 @@ fn sortPhdrs(self: *Elf) error{OutOfMemory}!void {
for (&[_]*?u16{
&self.phdr_zig_load_re_index,
&self.phdr_zig_load_ro_index,
&self.phdr_table_index,
&self.phdr_table_load_index,
&self.phdr_interp_index,
@@ -3487,7 +3483,6 @@ fn resetShdrIndexes(self: *Elf, backlinks: []const u32) void {
&self.versym_section_index,
&self.verneed_section_index,
&self.zig_text_section_index,
&self.zig_data_rel_ro_section_index,
&self.debug_info_section_index,
&self.debug_abbrev_section_index,
&self.debug_str_section_index,
@@ -3588,6 +3583,7 @@ fn updateSectionSizes(self: *Elf) !void {
if (self.zigObjectPtr()) |zo| blk: {
const sym_index = for ([_]?Symbol.Index{
zo.data_index,
zo.data_relro_index,
zo.bss_index,
}) |maybe_idx| {
if (maybe_idx) |idx| break idx;
@@ -3932,6 +3928,7 @@ pub fn allocateAllocSections(self: *Elf) !void {
if (self.zigObjectPtr()) |zo| blk: {
const existing_size = for ([_]?Symbol.Index{
zo.data_index,
zo.data_relro_index,
zo.eh_frame_index,
}) |maybe_sym_index| {
const sect_sym_index = maybe_sym_index orelse continue;
@@ -4105,6 +4102,7 @@ fn writeAtoms(self: *Elf) !void {
} else if (self.zigObjectPtr()) |zo| base_offset: {
const sym_index = for ([_]?Symbol.Index{
zo.data_index,
zo.data_relro_index,
zo.eh_frame_index,
}) |maybe_idx| {
if (maybe_idx) |idx| break idx;
@@ -4818,7 +4816,6 @@ pub fn isEffectivelyDynLib(self: Elf) bool {
pub fn isZigSection(self: Elf, shndx: u32) bool {
inline for (&[_]?u32{
self.zig_text_section_index,
self.zig_data_rel_ro_section_index,
}) |index| {
if (index == shndx) return true;
}

101
src/link/Elf/ZigObject.zig
View File

@@ -62,6 +62,8 @@ debug_rnglists_index: ?Symbol.Index = null,
eh_frame_index: ?Symbol.Index = null,
bss_index: ?Symbol.Index = null,
data_index: ?Symbol.Index = null,
data_relro_index: ?Symbol.Index = null,
rodata_index: ?Symbol.Index = null,
pub const global_symbol_bit: u32 = 0x80000000;
pub const symbol_mask: u32 = 0x7fffffff;
@@ -121,21 +123,6 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
.flags = elf.PF_X | elf.PF_R | elf.PF_W,
});
}
if (elf_file.phdr_zig_load_ro_index == null) {
const alignment = elf_file.page_size;
const filesz: u64 = 1024;
const off = try elf_file.findFreeSpace(filesz, alignment);
elf_file.phdr_zig_load_ro_index = try elf_file.addPhdr(.{
.type = elf.PT_LOAD,
.offset = off,
.filesz = filesz,
.addr = if (ptr_size >= 4) 0xc000000 else 0xa000,
.memsz = filesz,
.@"align" = alignment,
.flags = elf.PF_R | elf.PF_W,
});
}
}
if (elf_file.zig_text_section_index == null) {
@@ -159,27 +146,6 @@ pub fn init(self: *ZigObject, elf_file: *Elf, options: InitOptions) !void {
}
}
if (elf_file.zig_data_rel_ro_section_index == null) {
elf_file.zig_data_rel_ro_section_index = try elf_file.addSection(.{
.name = try elf_file.insertShString(".data.rel.ro.zig"),
.type = elf.SHT_PROGBITS,
.addralign = 1,
.flags = elf.SHF_ALLOC | elf.SHF_WRITE,
.offset = std.math.maxInt(u64),
});
const shdr = &elf_file.sections.items(.shdr)[elf_file.zig_data_rel_ro_section_index.?];
const phndx = &elf_file.sections.items(.phndx)[elf_file.zig_data_rel_ro_section_index.?];
try fillSection(elf_file, shdr, 1024, elf_file.phdr_zig_load_ro_index);
if (elf_file.base.isRelocatable()) {
_ = try elf_file.addRelaShdr(
try elf_file.insertShString(".rela.data.rel.ro.zig"),
elf_file.zig_data_rel_ro_section_index.?,
);
} else {
phndx.* = elf_file.phdr_zig_load_ro_index.?;
}
}
switch (comp.config.debug_format) {
.strip => {},
.dwarf => |v| {
@@ -1083,6 +1049,20 @@ pub fn lowerUav(
return .{ .mcv = .{ .load_symbol = metadata.symbol_index } };
}
const osec = if (self.data_relro_index) |sym_index|
self.symbol(sym_index).atom(elf_file).?.output_section_index
else osec: {
const osec = try elf_file.addSection(.{
.name = try elf_file.insertShString(".data.rel.ro"),
.type = elf.SHT_PROGBITS,
.addralign = 1,
.flags = elf.SHF_ALLOC | elf.SHF_WRITE,
.offset = std.math.maxInt(u64),
});
self.data_relro_index = osec;
break :osec osec;
};
var name_buf: [32]u8 = undefined;
const name = std.fmt.bufPrint(&name_buf, "__anon_{d}", .{
@intFromEnum(uav),
@@ -1093,7 +1073,7 @@ pub fn lowerUav(
name,
val,
uav_alignment,
elf_file.zig_data_rel_ro_section_index.?,
osec,
src_loc,
) catch |err| switch (err) {
error.OutOfMemory => return error.OutOfMemory,
@@ -1240,7 +1220,19 @@ fn getNavShdrIndex(
.offset = std.math.maxInt(u64),
});
}
if (is_const) return elf_file.zig_data_rel_ro_section_index.?;
if (is_const) {
if (self.data_relro_index) |symbol_index|
return self.symbol(symbol_index).atom(elf_file).?.output_section_index;
const osec = try elf_file.addSection(.{
.name = try elf_file.insertShString(".data.rel.ro"),
.type = elf.SHT_PROGBITS,
.addralign = 1,
.flags = elf.SHF_ALLOC | elf.SHF_WRITE,
.offset = std.math.maxInt(u64),
});
self.data_relro_index = try self.addSectionSymbol(gpa, ".data.rel.ro", .@"1", osec);
return osec;
}
if (nav_init != .none and Value.fromInterned(nav_init).isUndefDeep(zcu))
return switch (zcu.navFileScope(nav_index).mod.optimize_mode) {
.Debug, .ReleaseSafe => {
@@ -1253,7 +1245,12 @@ fn getNavShdrIndex(
.flags = elf.SHF_ALLOC | elf.SHF_WRITE,
.offset = std.math.maxInt(u64),
});
self.data_index = try self.addSectionSymbol(gpa, ".data", .@"1", osec);
self.data_index = try self.addSectionSymbol(
gpa,
".data",
Atom.Alignment.fromNonzeroByteUnits(ptr_size),
osec,
);
return osec;
},
.ReleaseFast, .ReleaseSmall => {
@@ -1293,7 +1290,12 @@ fn getNavShdrIndex(
.flags = elf.SHF_ALLOC | elf.SHF_WRITE,
.offset = std.math.maxInt(u64),
});
self.data_index = try self.addSectionSymbol(gpa, ".data", .@"1", osec);
self.data_index = try self.addSectionSymbol(
gpa,
".data",
Atom.Alignment.fromNonzeroByteUnits(ptr_size),
osec,
);
return osec;
}
@@ -1702,7 +1704,19 @@ fn updateLazySymbol(
const output_section_index = switch (sym.kind) {
.code => elf_file.zig_text_section_index.?,
.const_data => elf_file.zig_data_rel_ro_section_index.?,
.const_data => if (self.rodata_index) |sym_index|
self.symbol(sym_index).atom(elf_file).?.output_section_index
else osec: {
const osec = try elf_file.addSection(.{
.name = try elf_file.insertShString(".rodata"),
.type = elf.SHT_PROGBITS,
.addralign = 1,
.flags = elf.SHF_ALLOC,
.offset = std.math.maxInt(u64),
});
self.rodata_index = try self.addSectionSymbol(gpa, ".rodata", .@"1", osec);
break :osec osec;
},
};
const local_sym = self.symbol(symbol_index);
local_sym.name_offset = name_str_index;
@@ -2003,7 +2017,10 @@ fn allocateAtom(self: *ZigObject, atom_ptr: *Atom, elf_file: *Elf) !void {
}
shdr.sh_addralign = @max(shdr.sh_addralign, atom_ptr.alignment.toByteUnits().?);
const sect_atom_ptr = for ([_]?Symbol.Index{self.data_index}) |maybe_sym_index| {
const sect_atom_ptr = for ([_]?Symbol.Index{
self.data_index,
self.data_relro_index,
}) |maybe_sym_index| {
const sect_sym_index = maybe_sym_index orelse continue;
const sect_atom_ptr = self.symbol(sect_sym_index).atom(elf_file).?;
if (sect_atom_ptr.output_section_index == atom_ptr.output_section_index) break sect_atom_ptr;