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elf: put logic for allocating load segments in a helper
This commit is contained in:
Jakub Konka
parent
d9c5a26cfb
commit
9f05cb318b
157
src/link/Elf.zig
157
src/link/Elf.zig
@ -400,7 +400,7 @@ fn allocatedVirtualSize(self: *Elf, start: u64) u64 {
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return min_pos - start;
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}
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fn findFreeSpace(self: *Elf, object_size: u64, min_alignment: u32) u64 {
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fn findFreeSpace(self: *Elf, object_size: u64, min_alignment: u64) u64 {
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var start: u64 = 0;
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while (self.detectAllocCollision(start, object_size)) |item_end| {
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start = mem.alignForward(u64, item_end, min_alignment);
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@ -408,6 +408,38 @@ fn findFreeSpace(self: *Elf, object_size: u64, min_alignment: u32) u64 {
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return start;
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}
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const AllocateSegmentOpts = struct {
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addr: u64, // TODO find free VM space
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size: u64,
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alignment: u64,
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flags: u32 = elf.PF_R,
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};
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fn allocateSegment(self: *Elf, opts: AllocateSegmentOpts) !u16 {
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const index = @as(u16, @intCast(self.phdrs.items.len));
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try self.phdrs.ensureUnusedCapacity(self.base.allocator, 1);
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const off = self.findFreeSpace(opts.size, opts.alignment);
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log.debug("found PHDR {c}{c}{c} free space 0x{x} to 0x{x}", .{
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if (opts.flags & elf.PF_R != 0) @as(u8, 'R') else '_',
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if (opts.flags & elf.PF_W != 0) @as(u8, 'W') else '_',
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if (opts.flags & elf.PF_X != 0) @as(u8, 'X') else '_',
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off,
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off + opts.size,
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});
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self.phdrs.appendAssumeCapacity(.{
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.p_type = elf.PT_LOAD,
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.p_offset = off,
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.p_filesz = opts.size,
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.p_vaddr = opts.addr,
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.p_paddr = opts.addr,
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.p_memsz = opts.size,
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.p_align = opts.alignment,
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.p_flags = opts.flags,
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});
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self.phdr_table_dirty = true;
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return index;
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}
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pub fn populateMissingMetadata(self: *Elf) !void {
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const gpa = self.base.allocator;
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const small_ptr = switch (self.ptr_width) {
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@ -438,7 +470,6 @@ 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 = @intCast(self.phdrs.items.len);
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// TODO Same as for GOT
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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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@ -453,115 +484,67 @@ pub fn populateMissingMetadata(self: *Elf) !void {
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}
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if (self.phdr_load_re_index == null) {
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self.phdr_load_re_index = @intCast(self.phdrs.items.len);
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const file_size = self.base.options.program_code_size_hint;
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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 = 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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.p_filesz = file_size,
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.p_vaddr = entry_addr,
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.p_paddr = entry_addr,
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.p_memsz = file_size,
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.p_align = p_align,
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.p_flags = elf.PF_X | elf.PF_R | elf.PF_W,
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self.phdr_load_re_index = try self.allocateSegment(.{
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.addr = self.defaultEntryAddress(),
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.size = self.base.options.program_code_size_hint,
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.alignment = self.page_size,
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.flags = elf.PF_X | elf.PF_R | elf.PF_W,
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});
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self.entry_addr = null;
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self.phdr_table_dirty = true;
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}
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if (self.phdr_got_index == null) {
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self.phdr_got_index = @intCast(self.phdrs.items.len);
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const file_size = @as(u64, ptr_size) * self.base.options.symbol_count_hint;
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// We really only need ptr alignment but since we are using PROGBITS, linux requires
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// page align.
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const p_align = if (self.base.options.target.os.tag == .linux) self.page_size else @as(u16, ptr_size);
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const off = self.findFreeSpace(file_size, p_align);
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log.debug("found PT_LOAD GOT free space 0x{x} to 0x{x}", .{ off, off + file_size });
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// TODO instead of hard coding the vaddr, make a function to find a vaddr to put things at.
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// we'll need to re-use that function anyway, in case the GOT grows and overlaps something
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// else in virtual memory.
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const got_addr: u32 = if (self.base.options.target.ptrBitWidth() >= 32) 0x4000000 else 0x8000;
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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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.p_filesz = file_size,
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.p_vaddr = got_addr,
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.p_paddr = got_addr,
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.p_memsz = file_size,
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.p_align = p_align,
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.p_flags = elf.PF_R | elf.PF_W,
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const addr: u64 = if (self.base.options.target.ptrBitWidth() >= 32) 0x4000000 else 0x8000;
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// We really only need ptr alignment but since we are using PROGBITS, linux requires
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// page align.
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const alignment = if (self.base.options.target.os.tag == .linux) self.page_size else @as(u16, ptr_size);
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self.phdr_got_index = try self.allocateSegment(.{
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.addr = addr,
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.size = @as(u64, ptr_size) * self.base.options.symbol_count_hint,
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.alignment = alignment,
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.flags = elf.PF_R | elf.PF_W,
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});
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self.phdr_table_dirty = true;
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}
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if (self.phdr_load_ro_index == null) {
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self.phdr_load_ro_index = @intCast(self.phdrs.items.len);
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// TODO Find a hint about how much data need to be in rodata ?
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const file_size = 1024;
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// Same reason as for GOT
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const p_align = if (self.base.options.target.os.tag == .linux) self.page_size else @as(u16, ptr_size);
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const off = self.findFreeSpace(file_size, p_align);
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log.debug("found PT_LOAD RO free space 0x{x} to 0x{x}", .{ off, off + file_size });
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// TODO Same as for GOT
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const rodata_addr: u32 = if (self.base.options.target.ptrBitWidth() >= 32) 0xc000000 else 0xa000;
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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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.p_filesz = file_size,
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.p_vaddr = rodata_addr,
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.p_paddr = rodata_addr,
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.p_memsz = file_size,
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.p_align = p_align,
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.p_flags = elf.PF_R | elf.PF_W,
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const addr: u64 = if (self.base.options.target.ptrBitWidth() >= 32) 0xc000000 else 0xa000;
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// Same reason as for GOT
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const alignment = if (self.base.options.target.os.tag == .linux) self.page_size else @as(u16, ptr_size);
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self.phdr_load_ro_index = try self.allocateSegment(.{
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.addr = addr,
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.size = 1024,
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.alignment = alignment,
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.flags = elf.PF_R | elf.PF_W,
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});
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self.phdr_table_dirty = true;
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}
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if (self.phdr_load_rw_index == null) {
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self.phdr_load_rw_index = @intCast(self.phdrs.items.len);
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// TODO Find a hint about how much data need to be in data ?
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const file_size = 1024;
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// Same reason as for GOT
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const p_align = if (self.base.options.target.os.tag == .linux) self.page_size else @as(u16, ptr_size);
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const off = self.findFreeSpace(file_size, p_align);
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log.debug("found PT_LOAD RW free space 0x{x} to 0x{x}", .{ off, off + file_size });
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// TODO Same as for GOT
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const rwdata_addr: u32 = if (self.base.options.target.ptrBitWidth() >= 32) 0x10000000 else 0xc000;
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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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.p_filesz = file_size,
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.p_vaddr = rwdata_addr,
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.p_paddr = rwdata_addr,
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.p_memsz = file_size,
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.p_align = p_align,
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.p_flags = elf.PF_R | elf.PF_W,
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const addr: u64 = if (self.base.options.target.ptrBitWidth() >= 32) 0x10000000 else 0xc000;
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// Same reason as for GOT
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const alignment = if (self.base.options.target.os.tag == .linux) self.page_size else @as(u16, ptr_size);
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self.phdr_load_rw_index = try self.allocateSegment(.{
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.addr = addr,
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.size = 1024,
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.alignment = alignment,
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.flags = elf.PF_R | elf.PF_W,
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});
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self.phdr_table_dirty = true;
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}
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if (self.phdr_load_zerofill_index == null) {
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self.phdr_load_zerofill_index = @intCast(self.phdrs.items.len);
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const p_align = if (self.base.options.target.os.tag == .linux) self.page_size else @as(u16, ptr_size);
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const off = self.phdrs.items[self.phdr_load_rw_index.?].p_offset;
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log.debug("found PT_LOAD zerofill free space 0x{x} to 0x{x}", .{ off, off });
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// TODO Same as for GOT
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const addr: u32 = if (self.base.options.target.ptrBitWidth() >= 32) 0x14000000 else 0xf000;
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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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.p_filesz = 0,
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.p_vaddr = addr,
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.p_paddr = addr,
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.p_memsz = 0,
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.p_align = p_align,
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.p_flags = elf.PF_R | elf.PF_W,
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const addr: u64 = if (self.base.options.target.ptrBitWidth() >= 32) 0x14000000 else 0xf000;
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const alignment = if (self.base.options.target.os.tag == .linux) self.page_size else @as(u16, ptr_size);
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self.phdr_load_zerofill_index = try self.allocateSegment(.{
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.addr = addr,
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.size = 0,
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.alignment = alignment,
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.flags = elf.PF_R | elf.PF_W,
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});
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self.phdr_table_dirty = true;
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}
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if (self.shstrtab_section_index == null) {
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