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macho: limit export info to entrypoint and mh symbol when executable

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This commit is contained in:
Jakub Konka
2022-07-18 00:25:28 +02:00
parent 0f1b5d45bc
commit 2dfc78dc03
1 changed files with 61 additions and 24 deletions
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85
src/link/MachO.zig
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@@ -3289,9 +3289,9 @@ fn setEntryPoint(self: *MachO) !void {
if (self.base.options.output_mode != .Exe) return;
const seg = self.load_commands.items[self.text_segment_cmd_index.?].segment;
const entry_name = self.base.options.entry orelse "_main";
const global = self.globals.get(entry_name) orelse {
log.err("entrypoint '{s}' not found", .{entry_name});
const global = self.getEntryPoint() orelse {
const name = self.base.options.entry orelse "_main";
log.err("entrypoint '{s}' not found", .{name});
return error.MissingMainEntrypoint;
};
const sym = self.getSymbol(global);
@@ -5492,15 +5492,27 @@ fn gcAtoms(self: *MachO, gc_roots: *std.AutoHashMap(*Atom, void)) !void {
const gpa = self.base.allocator;
// Add all exports as GC roots
for (self.globals.values()) |global| {
const sym = self.getSymbol(global);
if (!sym.sect()) continue;
const gc_root = self.getAtomForSymbol(global) orelse {
log.debug("skipping {s}", .{self.getSymbolName(global)});
continue;
};
_ = try gc_roots.getOrPut(gc_root);
if (self.base.options.output_mode == .Exe) {
// Add entrypoint as GC root
if (self.getEntryPoint()) |global| {
if (self.getAtomForSymbol(global)) |gc_root| {
_ = try gc_roots.getOrPut(gc_root);
} else {
log.debug("skipping {s}", .{self.getSymbolName(global)});
}
}
} else {
assert(self.base.options.output_mode == .Lib);
// Add exports as GC roots
for (self.globals.values()) |global| {
const sym = self.getSymbol(global);
if (!sym.sect()) continue;
const gc_root = self.getAtomForSymbol(global) orelse {
log.debug("skipping {s}", .{self.getSymbolName(global)});
continue;
};
_ = try gc_roots.getOrPut(gc_root);
}
}
// Add any atom targeting an import as GC root
@@ -5836,19 +5848,37 @@ fn writeDyldInfoData(self: *MachO) !void {
const text_segment = self.load_commands.items[self.text_segment_cmd_index.?].segment;
const base_address = text_segment.inner.vmaddr;
for (self.globals.values()) |global| {
const sym = self.getSymbol(global);
if (sym.undf()) continue;
if (!sym.ext()) continue;
if (sym.n_desc == N_DESC_GCED) continue;
const sym_name = self.getSymbolName(global);
log.debug(" (putting '{s}' defined at 0x{x})", .{ sym_name, sym.n_value });
if (self.base.options.output_mode == .Exe) {
for (&[_]SymbolWithLoc{
self.getEntryPoint().?, // We would already errored out if no entrypoint was found.
self.globals.get("__mh_execute_header").?,
}) |global| {
const sym = self.getSymbol(global);
const sym_name = self.getSymbolName(global);
log.debug(" (putting '{s}' defined at 0x{x})", .{ sym_name, sym.n_value });
try trie.put(gpa, .{
.name = sym_name,
.vmaddr_offset = sym.n_value - base_address,
.export_flags = macho.EXPORT_SYMBOL_FLAGS_KIND_REGULAR,
});
}
} else {
assert(self.base.options.output_mode == .Lib);
for (self.globals.values()) |global| {
const sym = self.getSymbol(global);
try trie.put(gpa, .{
.name = sym_name,
.vmaddr_offset = sym.n_value - base_address,
.export_flags = macho.EXPORT_SYMBOL_FLAGS_KIND_REGULAR,
});
if (sym.undf()) continue;
if (!sym.ext()) continue;
if (sym.n_desc == N_DESC_GCED) continue;
const sym_name = self.getSymbolName(global);
log.debug(" (putting '{s}' defined at 0x{x})", .{ sym_name, sym.n_value });
try trie.put(gpa, .{
.name = sym_name,
.vmaddr_offset = sym.n_value - base_address,
.export_flags = macho.EXPORT_SYMBOL_FLAGS_KIND_REGULAR,
});
}
}
try trie.finalize(gpa);
@@ -6602,6 +6632,13 @@ pub fn getTlvPtrAtomForSymbol(self: *MachO, sym_with_loc: SymbolWithLoc) ?*Atom
return self.tlv_ptr_entries.items[tlv_ptr_index].atom;
}
/// Returns symbol location corresponding to the set entrypoint.
/// Asserts output mode is executable.
pub fn getEntryPoint(self: MachO) ?SymbolWithLoc {
const entry_name = self.base.options.entry orelse "_main";
return self.globals.get(entry_name);
}
pub fn findFirst(comptime T: type, haystack: []const T, start: usize, predicate: anytype) usize {
if (!@hasDecl(@TypeOf(predicate), "predicate"))
@compileError("Predicate is required to define fn predicate(@This(), T) bool");