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elf: add growAllocSection and growNonAllocSection

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Update `Dwarf.zig` to use `growNonAllocSection` for ELF and implement
routine to make space for `.debug_line` header.
This commit is contained in:
Jakub Konka
2022-12-08 13:49:23 +01:00
parent aa2f48f013
commit d7e42014ca
2 changed files with 137 additions and 151 deletions
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123
src/link/Dwarf.zig
View File

@@ -1150,29 +1150,9 @@ pub fn commitDeclState(
switch (self.bin_file.tag) {
.elf => {
const elf_file = self.bin_file.cast(File.Elf).?;
const debug_line_sect = &elf_file.sections.items[elf_file.debug_line_section_index.?];
if (needed_size != debug_line_sect.sh_size) {
if (needed_size > elf_file.allocatedSize(debug_line_sect.sh_offset)) {
const new_offset = elf_file.findFreeSpace(needed_size, 1);
const existing_size = last_src_fn.off;
log.debug("moving .debug_line section: {d} bytes from 0x{x} to 0x{x}", .{
existing_size,
debug_line_sect.sh_offset,
new_offset,
});
const amt = try elf_file.base.file.?.copyRangeAll(
debug_line_sect.sh_offset,
elf_file.base.file.?,
new_offset,
existing_size,
);
if (amt != existing_size) return error.InputOutput;
debug_line_sect.sh_offset = new_offset;
}
debug_line_sect.sh_size = needed_size;
elf_file.shdr_table_dirty = true; // TODO look into making only the one section dirty
elf_file.debug_line_header_dirty = true;
}
const shdr_index = elf_file.debug_line_section_index.?;
try elf_file.growNonAllocSection(shdr_index, needed_size, 1);
const debug_line_sect = elf_file.sections.items[shdr_index];
const file_pos = debug_line_sect.sh_offset + src_fn.off;
try pwriteDbgLineNops(
elf_file.base.file.?,
@@ -1417,29 +1397,9 @@ fn writeDeclDebugInfo(self: *Dwarf, atom: *Atom, dbg_info_buf: []const u8) !void
switch (self.bin_file.tag) {
.elf => {
const elf_file = self.bin_file.cast(File.Elf).?;
const debug_info_sect = &elf_file.sections.items[elf_file.debug_info_section_index.?];
if (needed_size != debug_info_sect.sh_size) {
if (needed_size > elf_file.allocatedSize(debug_info_sect.sh_offset)) {
const new_offset = elf_file.findFreeSpace(needed_size, 1);
const existing_size = last_decl.off;
log.debug("moving .debug_info section: {d} bytes from 0x{x} to 0x{x}", .{
existing_size,
debug_info_sect.sh_offset,
new_offset,
});
const amt = try elf_file.base.file.?.copyRangeAll(
debug_info_sect.sh_offset,
elf_file.base.file.?,
new_offset,
existing_size,
);
if (amt != existing_size) return error.InputOutput;
debug_info_sect.sh_offset = new_offset;
}
debug_info_sect.sh_size = needed_size;
elf_file.shdr_table_dirty = true; // TODO look into making only the one section dirty
elf_file.debug_info_header_dirty = true;
}
const shdr_index = elf_file.debug_info_section_index.?;
try elf_file.growNonAllocSection(shdr_index, needed_size, 1);
const debug_info_sect = elf_file.sections.items[shdr_index];
const file_pos = debug_info_sect.sh_offset + atom.off;
try pwriteDbgInfoNops(
elf_file.base.file.?,
@@ -1728,18 +1688,9 @@ pub fn writeDbgAbbrev(self: *Dwarf) !void {
switch (self.bin_file.tag) {
.elf => {
const elf_file = self.bin_file.cast(File.Elf).?;
const debug_abbrev_sect = &elf_file.sections.items[elf_file.debug_abbrev_section_index.?];
const allocated_size = elf_file.allocatedSize(debug_abbrev_sect.sh_offset);
if (needed_size > allocated_size) {
debug_abbrev_sect.sh_size = 0; // free the space
debug_abbrev_sect.sh_offset = elf_file.findFreeSpace(needed_size, 1);
}
debug_abbrev_sect.sh_size = needed_size;
log.debug(".debug_abbrev start=0x{x} end=0x{x}", .{
debug_abbrev_sect.sh_offset,
debug_abbrev_sect.sh_offset + needed_size,
});
const shdr_index = elf_file.debug_abbrev_section_index.?;
try elf_file.growNonAllocSection(shdr_index, needed_size, 1);
const debug_abbrev_sect = elf_file.sections.items[shdr_index];
const file_pos = debug_abbrev_sect.sh_offset + abbrev_offset;
try elf_file.base.file.?.pwriteAll(&abbrev_buf, file_pos);
},
@@ -2174,17 +2125,9 @@ pub fn writeDbgAranges(self: *Dwarf, addr: u64, size: u64) !void {
switch (self.bin_file.tag) {
.elf => {
const elf_file = self.bin_file.cast(File.Elf).?;
const debug_aranges_sect = &elf_file.sections.items[elf_file.debug_aranges_section_index.?];
const allocated_size = elf_file.allocatedSize(debug_aranges_sect.sh_offset);
if (needed_size > allocated_size) {
debug_aranges_sect.sh_size = 0; // free the space
debug_aranges_sect.sh_offset = elf_file.findFreeSpace(needed_size, 16);
}
debug_aranges_sect.sh_size = needed_size;
log.debug(".debug_aranges start=0x{x} end=0x{x}", .{
debug_aranges_sect.sh_offset,
debug_aranges_sect.sh_offset + needed_size,
});
const shdr_index = elf_file.debug_aranges_section_index.?;
try elf_file.growNonAllocSection(shdr_index, needed_size, 16);
const debug_aranges_sect = elf_file.sections.items[shdr_index];
const file_pos = debug_aranges_sect.sh_offset;
try elf_file.base.file.?.pwriteAll(di_buf.items, file_pos);
},
@@ -2335,21 +2278,40 @@ pub fn writeDbgLineHeader(self: *Dwarf, module: *Module) !void {
const needed_with_padding = padToIdeal(needed_bytes);
const delta = needed_with_padding - dbg_line_prg_off;
const d_sym = self.bin_file.cast(File.MachO).?.getDebugSymbols().?;
const sect_index = d_sym.debug_line_section_index.?;
const needed_size = @intCast(u32, d_sym.getSection(sect_index).size + delta);
try d_sym.growSection(sect_index, needed_size);
var src_fn = self.dbg_line_fn_first.?;
const last_fn = self.dbg_line_fn_last.?;
const file_pos = d_sym.getSection(sect_index).offset + src_fn.off;
var buffer = try gpa.alloc(u8, last_fn.off + last_fn.len - src_fn.off);
defer gpa.free(buffer);
const amt = try d_sym.file.preadAll(buffer, file_pos);
if (amt != buffer.len) return error.InputOutput;
try d_sym.file.pwriteAll(buffer, file_pos + delta);
switch (self.bin_file.tag) {
.elf => {
const elf_file = self.bin_file.cast(File.Elf).?;
const shdr_index = elf_file.debug_line_section_index.?;
const needed_size = elf_file.sections.items[shdr_index].sh_size + delta;
try elf_file.growNonAllocSection(shdr_index, needed_size, 1);
const file_pos = elf_file.sections.items[shdr_index].sh_offset + src_fn.off;
const amt = try elf_file.base.file.?.preadAll(buffer, file_pos);
if (amt != buffer.len) return error.InputOutput;
try elf_file.base.file.?.pwriteAll(buffer, file_pos + delta);
},
.macho => {
const d_sym = self.bin_file.cast(File.MachO).?.getDebugSymbols().?;
const sect_index = d_sym.debug_line_section_index.?;
const needed_size = @intCast(u32, d_sym.getSection(sect_index).size + delta);
try d_sym.growSection(sect_index, needed_size);
const file_pos = d_sym.getSection(sect_index).offset + src_fn.off;
const amt = try d_sym.file.preadAll(buffer, file_pos);
if (amt != buffer.len) return error.InputOutput;
try d_sym.file.pwriteAll(buffer, file_pos + delta);
},
.wasm => @panic("TODO grow section"),
else => unreachable,
}
while (true) {
src_fn.off += delta;
@@ -2568,7 +2530,10 @@ fn addDIFile(self: *Dwarf, mod: *Module, decl_index: Module.Decl.Index) !u28 {
const gop = try self.di_files.getOrPut(self.allocator, file_scope);
if (!gop.found_existing) {
switch (self.bin_file.tag) {
.elf => self.bin_file.cast(File.Elf).?.debug_line_header_dirty = true,
.elf => {
const elf_file = self.bin_file.cast(File.Elf).?;
elf_file.markDirty(elf_file.debug_line_section_index.?, null);
},
.macho => {
const d_sym = self.bin_file.cast(File.MachO).?.getDebugSymbols().?;
d_sym.markDirty(d_sym.debug_line_section_index.?);

165
src/link/Elf.zig
View File

@@ -931,6 +931,94 @@ pub fn populateMissingMetadata(self: *Elf) !void {
}
}
fn growAllocSection(self: *Elf, shdr_index: u16, phdr_index: u16, needed_size: u64) !void {
// TODO Also detect virtual address collisions.
const shdr = &self.sections.items[shdr_index];
const phdr = &self.program_headers.items[phdr_index];
if (needed_size > self.allocatedSize(shdr.sh_offset)) {
// Must move the entire section.
const new_offset = self.findFreeSpace(needed_size, self.page_size);
const existing_size = if (self.atoms.get(phdr_index)) |last| blk: {
const sym = self.local_symbols.items[last.local_sym_index];
break :blk (sym.st_value + sym.st_size) - phdr.p_vaddr;
} else if (shdr_index == self.got_section_index.?) blk: {
break :blk shdr.sh_size;
} else 0;
shdr.sh_size = 0;
log.debug("new '{s}' file offset 0x{x} to 0x{x}", .{
self.getString(shdr.sh_name),
new_offset,
new_offset + existing_size,
});
const amt = try self.base.file.?.copyRangeAll(shdr.sh_offset, self.base.file.?, new_offset, existing_size);
if (amt != existing_size) return error.InputOutput;
shdr.sh_offset = new_offset;
phdr.p_offset = new_offset;
}
shdr.sh_size = needed_size;
phdr.p_memsz = needed_size;
phdr.p_filesz = needed_size;
self.markDirty(shdr_index, phdr_index);
}
pub fn growNonAllocSection(self: *Elf, shdr_index: u16, needed_size: u64, min_alignment: u32) !void {
const shdr = &self.sections.items[shdr_index];
if (needed_size > self.allocatedSize(shdr.sh_offset)) {
const existing_size = if (self.symtab_section_index.? == shdr_index) blk: {
const sym_size: u64 = switch (self.ptr_width) {
.p32 => @sizeOf(elf.Elf32_Sym),
.p64 => @sizeOf(elf.Elf64_Sym),
};
break :blk @as(u64, shdr.sh_info) * sym_size;
} else shdr.sh_size;
shdr.sh_size = 0;
// Move all the symbols to a new file location.
const new_offset = self.findFreeSpace(needed_size, min_alignment);
log.debug("moving '{s}' from 0x{x} to 0x{x}", .{ self.getString(shdr.sh_name), shdr.sh_offset, new_offset });
const amt = try self.base.file.?.copyRangeAll(
shdr.sh_offset,
self.base.file.?,
new_offset,
existing_size,
);
if (amt != existing_size) return error.InputOutput;
shdr.sh_offset = new_offset;
}
shdr.sh_size = needed_size; // anticipating adding the global symbols later
self.markDirty(shdr_index, null);
}
pub fn markDirty(self: *Elf, shdr_index: u16, phdr_index: ?u16) void {
self.shdr_table_dirty = true; // TODO look into only writing one section
if (phdr_index) |_| {
self.phdr_table_dirty = true; // TODO look into making only the one program header dirty
}
if (self.dwarf) |_| {
if (self.debug_info_section_index.? == shdr_index) {
self.debug_info_header_dirty = true;
} else if (self.debug_line_section_index.? == shdr_index) {
self.debug_line_header_dirty = true;
} else if (self.debug_abbrev_section_index.? == shdr_index) {
self.debug_abbrev_section_dirty = true;
} else if (self.debug_str_section_index.? == shdr_index) {
self.debug_strtab_dirty = true;
} else if (self.debug_aranges_section_index.? == shdr_index) {
self.debug_aranges_section_dirty = true;
}
}
}
pub fn flush(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
if (self.base.options.emit == null) {
if (build_options.have_llvm) {
@@ -2134,27 +2222,10 @@ fn allocateTextBlock(self: *Elf, text_block: *TextBlock, new_block_size: u64, al
const expand_text_section = block_placement == null or block_placement.?.next == null;
if (expand_text_section) {
const text_capacity = self.allocatedSize(shdr.sh_offset);
const needed_size = (vaddr + new_block_size) - phdr.p_vaddr;
if (needed_size > text_capacity) {
// Must move the entire section.
const new_offset = self.findFreeSpace(needed_size, self.page_size);
const text_size = if (self.atoms.get(phdr_index)) |last| blk: {
const sym = self.local_symbols.items[last.local_sym_index];
break :blk (sym.st_value + sym.st_size) - phdr.p_vaddr;
} else 0;
log.debug("new PT_LOAD file offset 0x{x} to 0x{x}", .{ new_offset, new_offset + text_size });
const amt = try self.base.file.?.copyRangeAll(shdr.sh_offset, self.base.file.?, new_offset, text_size);
if (amt != text_size) return error.InputOutput;
shdr.sh_offset = new_offset;
phdr.p_offset = new_offset;
}
try self.growAllocSection(shdr_index, phdr_index, needed_size);
_ = try self.atoms.put(self.base.allocator, phdr_index, text_block);
shdr.sh_size = needed_size;
phdr.p_memsz = needed_size;
phdr.p_filesz = needed_size;
if (self.dwarf) |_| {
// The .debug_info section has `low_pc` and `high_pc` values which is the virtual address
// range of the compilation unit. When we expand the text section, this range changes,
@@ -2165,9 +2236,6 @@ fn allocateTextBlock(self: *Elf, text_block: *TextBlock, new_block_size: u64, al
// model each package as a different compilation unit.
self.debug_aranges_section_dirty = true;
}
self.phdr_table_dirty = true; // TODO look into making only the one program header dirty
self.shdr_table_dirty = true; // TODO look into making only the one section dirty
}
shdr.sh_addralign = math.max(shdr.sh_addralign, alignment);
@@ -2747,31 +2815,14 @@ fn writeSectHeader(self: *Elf, index: usize) !void {
}
fn writeOffsetTableEntry(self: *Elf, index: usize) !void {
const shdr = &self.sections.items[self.got_section_index.?];
const phdr = &self.program_headers.items[self.phdr_got_index.?];
const entry_size: u16 = self.archPtrWidthBytes();
if (self.offset_table_count_dirty) {
// TODO Also detect virtual address collisions.
const allocated_size = self.allocatedSize(shdr.sh_offset);
const needed_size = self.offset_table.items.len * entry_size;
if (needed_size > allocated_size) {
// Must move the entire got section.
const new_offset = self.findFreeSpace(needed_size, self.page_size);
const amt = try self.base.file.?.copyRangeAll(shdr.sh_offset, self.base.file.?, new_offset, shdr.sh_size);
if (amt != shdr.sh_size) return error.InputOutput;
shdr.sh_offset = new_offset;
phdr.p_offset = new_offset;
}
shdr.sh_size = needed_size;
phdr.p_memsz = needed_size;
phdr.p_filesz = needed_size;
self.shdr_table_dirty = true; // TODO look into making only the one section dirty
self.phdr_table_dirty = true; // TODO look into making only the one program header dirty
try self.growAllocSection(self.got_section_index.?, self.phdr_got_index.?, needed_size);
self.offset_table_count_dirty = false;
}
const endian = self.base.options.target.cpu.arch.endian();
const shdr = &self.sections.items[self.got_section_index.?];
const off = shdr.sh_offset + @as(u64, entry_size) * index;
switch (entry_size) {
2 => {
@@ -2810,23 +2861,8 @@ fn writeSymbol(self: *Elf, index: usize) !void {
.p64 => @alignOf(elf.Elf64_Sym),
};
const needed_size = (self.local_symbols.items.len + self.global_symbols.items.len) * sym_size;
if (needed_size > self.allocatedSize(syms_sect.sh_offset)) {
// Move all the symbols to a new file location.
const new_offset = self.findFreeSpace(needed_size, sym_align);
log.debug("moving '.symtab' from 0x{x} to 0x{x}", .{ syms_sect.sh_offset, new_offset });
const existing_size = @as(u64, syms_sect.sh_info) * sym_size;
const amt = try self.base.file.?.copyRangeAll(
syms_sect.sh_offset,
self.base.file.?,
new_offset,
existing_size,
);
if (amt != existing_size) return error.InputOutput;
syms_sect.sh_offset = new_offset;
}
try self.growNonAllocSection(self.symtab_section_index.?, needed_size, sym_align);
syms_sect.sh_info = @intCast(u32, self.local_symbols.items.len);
syms_sect.sh_size = needed_size; // anticipating adding the global symbols later
self.shdr_table_dirty = true; // TODO look into only writing one section
}
const foreign_endian = self.base.options.target.cpu.arch.endian() != builtin.cpu.arch.endian();
const off = switch (self.ptr_width) {
@@ -2874,22 +2910,7 @@ fn writeAllGlobalSymbols(self: *Elf) !void {
.p64 => @alignOf(elf.Elf64_Sym),
};
const needed_size = (self.local_symbols.items.len + self.global_symbols.items.len) * sym_size;
if (needed_size > self.allocatedSize(syms_sect.sh_offset)) {
// Move all the symbols to a new file location.
const new_offset = self.findFreeSpace(needed_size, sym_align);
log.debug("moving '.symtab' from 0x{x} to 0x{x}", .{ syms_sect.sh_offset, new_offset });
const existing_size = @as(u64, syms_sect.sh_info) * sym_size;
const amt = try self.base.file.?.copyRangeAll(
syms_sect.sh_offset,
self.base.file.?,
new_offset,
existing_size,
);
if (amt != existing_size) return error.InputOutput;
syms_sect.sh_offset = new_offset;
}
syms_sect.sh_size = needed_size; // anticipating adding the global symbols later
self.shdr_table_dirty = true; // TODO look into only writing one section
try self.growNonAllocSection(self.symtab_section_index.?, needed_size, sym_align);
const foreign_endian = self.base.options.target.cpu.arch.endian() != builtin.cpu.arch.endian();
const global_syms_off = syms_sect.sh_offset + self.local_symbols.items.len * sym_size;