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elf: remove explicit load segment alloc - we can replicate programmatically now

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This commit is contained in:
Jakub Konka 2023-09-28 11:46:40 +02:00
parent df285949f7
commit 42011a8249
1 changed files with 7 additions and 31 deletions
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38
src/link/Elf.zig
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@ -429,15 +429,15 @@ pub fn allocateSegment(self: *Elf, opts: AllocateSegmentOpts) error{OutOfMemory}
const addr = opts.addr orelse blk: {
const reserved_capacity = self.calcImageBase() * 4;
// Calculate largest VM address
const count = self.phdrs.items.len;
var addresses = std.ArrayList(u64).init(gpa);
defer addresses.deinit();
try addresses.ensureTotalCapacityPrecise(count);
try addresses.ensureTotalCapacityPrecise(self.phdrs.items.len);
for (self.phdrs.items) |phdr| {
if (phdr.p_type != elf.PT_LOAD) continue;
addresses.appendAssumeCapacity(phdr.p_vaddr + reserved_capacity);
}
mem.sort(u64, addresses.items, {}, std.sort.asc(u64));
break :blk mem.alignForward(u64, addresses.items[count - 1], opts.alignment);
break :blk mem.alignForward(u64, addresses.pop(), opts.alignment);
};
log.debug("allocating phdr({d})({c}{c}{c}) from 0x{x} to 0x{x} (0x{x} - 0x{x})", .{
index,
@ -543,7 +543,6 @@ pub fn populateMissingMetadata(self: *Elf) !void {
};
const ptr_size: u8 = self.ptrWidthBytes();
const is_linux = self.base.options.target.os.tag == .linux;
const large_addrspace = self.base.options.target.ptrBitWidth() >= 32;
const image_base = self.calcImageBase();
if (self.phdr_table_index == null) {
@ -566,23 +565,16 @@ pub fn populateMissingMetadata(self: *Elf) !void {
}
if (self.phdr_table_load_index == null) {
self.phdr_table_load_index = @intCast(self.phdrs.items.len);
try self.phdrs.append(gpa, .{
.p_type = elf.PT_LOAD,
.p_offset = 0,
.p_filesz = 0,
.p_vaddr = image_base,
.p_paddr = image_base,
.p_memsz = 0,
.p_align = self.page_size,
.p_flags = elf.PF_R,
self.phdr_table_load_index = try self.allocateSegment(.{
.addr = image_base,
.size = 0,
.alignment = self.page_size,
});
self.phdr_table_dirty = true;
}
if (self.phdr_load_re_index == null) {
self.phdr_load_re_index = try self.allocateSegment(.{
.addr = self.defaultEntryAddress(),
.size = self.base.options.program_code_size_hint,
.alignment = self.page_size,
.flags = elf.PF_X | elf.PF_R | elf.PF_W,
@ -591,12 +583,10 @@ pub fn populateMissingMetadata(self: *Elf) !void {
}
if (self.phdr_got_index == null) {
const addr: u64 = if (large_addrspace) 0x4000000 else 0x8000;
// We really only need ptr alignment but since we are using PROGBITS, linux requires
// page align.
const alignment = if (is_linux) self.page_size else @as(u16, ptr_size);
self.phdr_got_index = try self.allocateSegment(.{
.addr = addr,
.size = @as(u64, ptr_size) * self.base.options.symbol_count_hint,
.alignment = alignment,
.flags = elf.PF_R | elf.PF_W,
@ -604,10 +594,8 @@ pub fn populateMissingMetadata(self: *Elf) !void {
}
if (self.phdr_load_ro_index == null) {
const addr: u64 = if (large_addrspace) 0xc000000 else 0xa000;
const alignment = if (is_linux) self.page_size else @as(u16, ptr_size);
self.phdr_load_ro_index = try self.allocateSegment(.{
.addr = addr,
.size = 1024,
.alignment = alignment,
.flags = elf.PF_R | elf.PF_W,
@ -615,10 +603,8 @@ pub fn populateMissingMetadata(self: *Elf) !void {
}
if (self.phdr_load_rw_index == null) {
const addr: u64 = if (large_addrspace) 0x10000000 else 0xc000;
const alignment = if (is_linux) self.page_size else @as(u16, ptr_size);
self.phdr_load_rw_index = try self.allocateSegment(.{
.addr = addr,
.size = 1024,
.alignment = alignment,
.flags = elf.PF_R | elf.PF_W,
@ -626,10 +612,8 @@ pub fn populateMissingMetadata(self: *Elf) !void {
}
if (self.phdr_load_zerofill_index == null) {
const addr: u64 = if (large_addrspace) 0x14000000 else 0xf000;
const alignment = if (is_linux) self.page_size else @as(u16, ptr_size);
self.phdr_load_zerofill_index = try self.allocateSegment(.{
.addr = addr,
.size = 0,
.alignment = alignment,
.flags = elf.PF_R | elf.PF_W,
@ -3820,14 +3804,6 @@ pub fn calcImageBase(self: Elf) u64 {
};
}
pub fn defaultEntryAddress(self: Elf) u64 {
if (self.entry_addr) |addr| return addr;
return switch (self.base.options.target.cpu.arch) {
.spu_2 => 0,
else => default_entry_addr,
};
}
pub fn isDynLib(self: Elf) bool {
return self.base.options.output_mode == .Lib and self.base.options.link_mode == .Dynamic;
}