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elf: set output section index when parsing objects

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This commit is contained in:
Jakub Konka 2023-09-12 17:35:56 +02:00
parent 44e84af874
commit 472d326a8c
2 changed files with 64 additions and 25 deletions
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11
src/link/Elf.zig
View File

@ -1043,14 +1043,17 @@ pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node
self.linker_defined_index = index;
}
// Symbol resolution happens here
try self.addLinkerDefinedSymbols();
// Resolve symbols
self.resolveSymbols();
self.markImportsExports();
self.claimUnresolved();
// Scan and create missing synthetic entries such as GOT indirection
try self.scanRelocs();
// Allocate atoms parsed from input object files
self.allocateObjects();
self.allocateLinkerDefinedSymbols();
// Beyond this point, everything has been allocated a virtual address and we can resolve
@ -1402,6 +1405,10 @@ fn scanRelocs(self: *Elf) !void {
}
}
fn allocateObjects(self: *Elf) void {
_ = self;
}
fn linkWithLLD(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) !void {
const tracy = trace(@src());
defer tracy.end();

78
src/link/Elf/Object.zig
View File

@ -17,7 +17,6 @@ comdat_groups: std.ArrayListUnmanaged(Elf.ComdatGroup.Index) = .{},
fdes: std.ArrayListUnmanaged(Fde) = .{},
cies: std.ArrayListUnmanaged(Cie) = .{},
needs_exec_stack: bool = false,
alive: bool = true,
num_dynrelocs: u32 = 0,
@ -80,12 +79,12 @@ pub fn parse(self: *Object, elf_file: *Elf) !void {
try self.initAtoms(elf_file);
try self.initSymtab(elf_file);
for (self.shdrs.items, 0..) |shdr, i| {
const atom = elf_file.atom(self.atoms.items[i]) orelse continue;
if (!atom.alive) continue;
if (shdr.sh_type == elf.SHT_X86_64_UNWIND or mem.eql(u8, atom.name(elf_file), ".eh_frame"))
try self.parseEhFrame(@as(u16, @intCast(i)), elf_file);
}
// for (self.shdrs.items, 0..) |shdr, i| {
// const atom = elf_file.atom(self.atoms.items[i]) orelse continue;
// if (!atom.alive) continue;
// if (shdr.sh_type == elf.SHT_X86_64_UNWIND or mem.eql(u8, atom.name(elf_file), ".eh_frame"))
// try self.parseEhFrame(@as(u16, @intCast(i)), elf_file);
// }
}
fn initAtoms(self: *Object, elf_file: *Elf) !void {
@ -148,20 +147,6 @@ fn initAtoms(self: *Object, elf_file: *Elf) !void {
else => {
const name = self.strings.getAssumeExists(shdr.sh_name);
const shndx = @as(u16, @intCast(i));
// if (mem.eql(u8, ".note.GNU-stack", name)) {
// if (shdr.sh_flags & elf.SHF_EXECINSTR != 0) {
// if (!elf_file.options.z_execstack or !elf_file.options.z_execstack_if_needed) {
// elf_file.base.warn(
// "{}: may cause segmentation fault as this file requested executable stack",
// .{self.fmtPath()},
// );
// }
// self.needs_exec_stack = true;
// }
// continue;
// }
if (self.skipShdr(shndx, elf_file)) continue;
try self.addAtom(shdr, shndx, name, elf_file);
},
@ -187,6 +172,7 @@ fn addAtom(self: *Object, shdr: elf.Elf64_Shdr, shndx: u16, name: [:0]const u8,
atom.name_offset = try elf_file.strtab.insert(elf_file.base.allocator, name);
atom.file_index = self.index;
atom.input_section_index = shndx;
atom.output_section_index = self.getOutputSectionIndex(elf_file, shdr);
atom.alive = true;
self.atoms.items[shndx] = atom_index;
@ -201,15 +187,61 @@ fn addAtom(self: *Object, shdr: elf.Elf64_Shdr, shndx: u16, name: [:0]const u8,
}
}
fn getOutputSectionIndex(self: *Object, elf_file: *Elf, shdr: elf.Elf64_Shdr) u16 {
const name = blk: {
const name = self.strings.getAssumeExists(shdr.sh_name);
// if (shdr.sh_flags & elf.SHF_MERGE != 0) break :blk name;
const sh_name_prefixes: []const [:0]const u8 = &.{
".text", ".data.rel.ro", ".data", ".rodata", ".bss.rel.ro", ".bss",
".init_array", ".fini_array", ".tbss", ".tdata", ".gcc_except_table", ".ctors",
".dtors", ".gnu.warning",
};
inline for (sh_name_prefixes) |prefix| {
if (std.mem.eql(u8, name, prefix) or std.mem.startsWith(u8, name, prefix ++ ".")) {
break :blk prefix;
}
}
break :blk name;
};
const @"type" = switch (shdr.sh_type) {
elf.SHT_NULL => unreachable,
elf.SHT_PROGBITS => blk: {
if (std.mem.eql(u8, name, ".init_array") or std.mem.startsWith(u8, name, ".init_array."))
break :blk elf.SHT_INIT_ARRAY;
if (std.mem.eql(u8, name, ".fini_array") or std.mem.startsWith(u8, name, ".fini_array."))
break :blk elf.SHT_FINI_ARRAY;
break :blk shdr.sh_type;
},
elf.SHT_X86_64_UNWIND => elf.SHT_PROGBITS,
else => shdr.sh_type,
};
const flags = blk: {
const flags = shdr.sh_flags & ~@as(u64, elf.SHF_COMPRESSED | elf.SHF_GROUP | elf.SHF_GNU_RETAIN);
break :blk switch (@"type") {
elf.SHT_INIT_ARRAY, elf.SHT_FINI_ARRAY => flags | elf.SHF_WRITE,
else => flags,
};
};
_ = flags;
const out_shndx = elf_file.sectionByName(name) orelse {
log.err("{}: output section {s} not found", .{ self.fmtPath(), name });
@panic("TODO: missing output section!");
};
return out_shndx;
}
fn skipShdr(self: *Object, index: u16, elf_file: *Elf) bool {
_ = elf_file;
const shdr = self.shdrs.items[index];
const name = self.strings.getAssumeExists(shdr.sh_name);
const ignore = blk: {
if (mem.startsWith(u8, name, ".note")) break :blk true;
if (mem.startsWith(u8, name, ".comment")) break :blk true;
if (mem.startsWith(u8, name, ".llvm_addrsig")) break :blk true;
if (elf_file.base.options.strip and shdr.sh_flags & elf.SHF_ALLOC == 0 and
mem.startsWith(u8, name, ".debug")) break :blk true;
if (mem.startsWith(u8, name, ".eh_frame")) break :blk true;
// if (elf_file.base.options.strip and shdr.sh_flags & elf.SHF_ALLOC == 0 and
// mem.startsWith(u8, name, ".debug")) break :blk true;
if (shdr.sh_flags & elf.SHF_ALLOC == 0 and mem.startsWith(u8, name, ".debug")) break :blk true;
break :blk false;
};
return ignore;