elf: actually commit relocatable.zig

src/Elf/relocatable.zig

@@ -0,0 +1,166 @@
+pub fn flush(elf_file: *Elf) !void {
+    claimUnresolved(elf_file);
+    try initSections(elf_file);
+    try elf_file.sortSections();
+    // try self.addAtomsToSections();
+    // try self.calcSectionSizesRelocatable();
+
+    // try self.allocateSectionsRelocatable();
+    // self.allocateAtoms();
+    // self.allocateLocals();
+    // self.allocateGlobals();
+    // self.allocateSyntheticSymbols();
+
+    // self.shoff = blk: {
+    //     const shdr = self.sections.items(.shdr)[self.sections.len - 1];
+    //     const offset = shdr.sh_offset + shdr.sh_size;
+    //     break :blk mem.alignForward(u64, offset, @alignOf(elf.Elf64_Shdr));
+    // };
+
+    Elf.state_log.debug("{}", .{elf_file.dumpState()});
+
+    // try self.writeAtomsRelocatable();
+    // try self.writeSyntheticSectionsRelocatable();
+    // try self.writeShdrs();
+    // try self.writeHeader();
+
+    elf_file.base.reportWarningsAndErrorsAndExit();
+}
+
+fn claimUnresolved(elf_file: *Elf) void {
+    for (elf_file.objects.items) |index| {
+        const object = elf_file.getFile(index).?.object;
+        const first_global = object.first_global orelse return;
+        for (object.getGlobals(), 0..) |global_index, i| {
+            const sym_idx = @as(u32, @intCast(first_global + i));
+            const sym = object.symtab[sym_idx];
+            if (sym.st_shndx != elf.SHN_UNDEF) continue;
+
+            const global = elf_file.getSymbol(global_index);
+            if (global.getFile(elf_file)) |_| {
+                if (global.getSourceSymbol(elf_file).st_shndx != elf.SHN_UNDEF) continue;
+            }
+
+            global.value = 0;
+            global.atom = 0;
+            global.sym_idx = sym_idx;
+            global.file = object.index;
+        }
+    }
+}
+
+fn initSections(elf_file: *Elf) !void {
+    for (elf_file.objects.items) |index| {
+        const object = elf_file.getFile(index).?.object;
+
+        for (object.atoms.items) |atom_index| {
+            const atom = elf_file.getAtom(atom_index) orelse continue;
+            if (!atom.flags.alive) continue;
+            atom.out_shndx = try object.initOutputSection(elf_file, atom.getInputShdr(elf_file));
+
+            const rela_shdr = object.getShdrs()[atom.relocs_shndx];
+            if (rela_shdr.sh_type != elf.SHT_NULL) {
+                const out_rela_shndx = try object.initOutputSection(elf_file, rela_shdr);
+                elf_file.sections.items(.shdr)[out_rela_shndx].sh_flags |= elf.SHF_INFO_LINK;
+                elf_file.sections.items(.rela_shndx)[atom.out_shndx] = out_rela_shndx;
+            }
+        }
+    }
+
+    const needs_eh_frame = for (elf_file.objects.items) |index| {
+        if (elf_file.getFile(index).?.object.cies.items.len > 0) break true;
+    } else false;
+    if (needs_eh_frame) {
+        elf_file.eh_frame_sect_index = try elf_file.addSection(.{
+            .name = ".eh_frame",
+            .flags = elf.SHF_ALLOC,
+            .type = elf.SHT_PROGBITS,
+            .addralign = @alignOf(u64),
+        });
+        elf_file.sections.items(.rela_shndx)[elf_file.eh_frame_sect_index.?] = try elf_file.addSection(.{
+            .name = ".rela.eh_frame",
+            .type = elf.SHT_RELA,
+            .flags = elf.SHF_INFO_LINK,
+            .entsize = @sizeOf(elf.Elf64_Rela),
+            .addralign = @alignOf(elf.Elf64_Rela),
+        });
+    }
+
+    try initComdatGroups(elf_file);
+    try elf_file.initSymtab();
+    try elf_file.initShStrtab();
+}
+
+fn initComdatGroups(elf_file: *Elf) !void {
+    const gpa = elf_file.base.allocator;
+
+    for (elf_file.objects.items) |index| {
+        const object = elf_file.getFile(index).?.object;
+
+        for (object.comdat_groups.items) |cg_index| {
+            const cg = elf_file.getComdatGroup(cg_index);
+            const cg_owner = elf_file.getComdatGroupOwner(cg.owner);
+            if (cg_owner.file != index) continue;
+
+            const cg_sec = try elf_file.comdat_group_sections.addOne(gpa);
+            cg_sec.* = .{
+                .shndx = try elf_file.addSection(.{
+                    .name = ".group",
+                    .type = elf.SHT_GROUP,
+                    .entsize = @sizeOf(u32),
+                    .addralign = @alignOf(u32),
+                }),
+                .cg_index = cg_index,
+            };
+        }
+    }
+}
+
+// fn calcSectionSizesRelocatable(self: *Elf) !void {
+//     for (self.sections.items(.shdr), self.sections.items(.atoms)) |*shdr, atoms| {
+//         if (atoms.items.len == 0) continue;
+
+//         for (atoms.items) |atom_index| {
+//             const atom = self.getAtom(atom_index).?;
+//             const alignment = try math.powi(u64, 2, atom.alignment);
+//             const offset = mem.alignForward(u64, shdr.sh_size, alignment);
+//             const padding = offset - shdr.sh_size;
+//             atom.value = offset;
+//             shdr.sh_size += padding + atom.size;
+//             shdr.sh_addralign = @max(shdr.sh_addralign, alignment);
+//         }
+//     }
+
+//     // TODO rela sections
+
+//     if (self.eh_frame_sect_index) |index| {
+//         const shdr = &self.sections.items(.shdr)[index];
+//         shdr.sh_size = try eh_frame.calcEhFrameSize(self);
+//         shdr.sh_addralign = @alignOf(u64);
+//     }
+
+//     try self.calcSymtabSize();
+//     self.calcComdatGroupsSizes();
+
+//     if (self.shstrtab_sect_index) |index| {
+//         const shdr = &self.sections.items(.shdr)[index];
+//         shdr.sh_size = self.shstrtab.buffer.items.len;
+//     }
+// }
+
+// fn calcComdatGroupsSizes(self: *Elf) void {
+//     for (self.comdat_group_sections.items) |cg| {
+//         const shdr = &self.sections.items(.shdr)[cg.shndx];
+//         shdr.sh_size = cg.size(self);
+//         shdr.sh_link = self.symtab_sect_index.?;
+
+//         const sym = self.getSymbol(cg.getSymbol(self));
+//         shdr.sh_info = sym.getOutputSymtabIndex(self) orelse
+//             self.getSectionSymbolOutputSymtabIndex(sym.shndx);
+//     }
+// }
+
+const elf = std.elf;
+const std = @import("std");
+
+const Elf = @import("../Elf.zig");