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compiler: avoid use of undefined memory

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InternPool is nice in some ways but it also comes with its own set of
footguns. This commit fixes 5 instances. I see quite a few Valgrind
warnings remaining when running the behavior tests.

Perhaps the solution is to have stringToSlice return a struct with start
and length as indexes, which has a format function?
This commit is contained in:
Andrew Kelley 2023-06-02 00:33:28 -07:00
parent 69b7b91092
commit f1c900c72e
2 changed files with 31 additions and 7 deletions
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33
src/Module.zig
View File

@ -576,7 +576,6 @@ pub const Decl = struct {
}
mod.destroyFunc(func);
}
_ = mod.memoized_decls.remove(decl.val.ip_index);
}
/// This name is relative to the containing namespace of the decl.
@ -690,10 +689,30 @@ pub const Decl = struct {
}
pub fn getFullyQualifiedName(decl: Decl, mod: *Module) !InternPool.NullTerminatedString {
const gpa = mod.gpa;
if (decl.name_fully_qualified) return decl.name;
const ip = &mod.intern_pool;
const count = count: {
var count: usize = ip.stringToSlice(decl.name).len + 1;
var ns: Namespace.Index = decl.src_namespace;
while (true) {
const namespace = mod.namespacePtr(ns);
const ns_decl_index = namespace.getDeclIndex(mod);
const ns_decl = mod.declPtr(ns_decl_index);
count += ip.stringToSlice(ns_decl.name).len + 1;
ns = namespace.parent.unwrap() orelse {
count += namespace.file_scope.sub_file_path.len;
break :count count;
};
}
};
const gpa = mod.gpa;
const start = ip.string_bytes.items.len;
try decl.renderFullyQualifiedName(mod, ip.string_bytes.writer(gpa));
// Protects reads of interned strings from being reallocated during the call to
// renderFullyQualifiedName.
try ip.string_bytes.ensureUnusedCapacity(gpa, count);
decl.renderFullyQualifiedName(mod, ip.string_bytes.writer(gpa)) catch unreachable;
// Sanitize the name for nvptx which is more restrictive.
// TODO This should be handled by the backend, not the frontend. Have a
@ -4018,7 +4037,7 @@ pub fn ensureDeclAnalyzed(mod: *Module, decl_index: Decl.Index) SemaError!void {
.unreferenced => false,
};
var decl_prog_node = mod.sema_prog_node.start(mod.intern_pool.stringToSlice(decl.name), 0);
var decl_prog_node = mod.sema_prog_node.start("", 0);
decl_prog_node.activate();
defer decl_prog_node.end();
@ -5774,9 +5793,11 @@ pub fn createAnonymousDeclFromDecl(
const new_decl_index = try mod.allocateNewDecl(namespace, src_decl.src_node, src_scope);
errdefer mod.destroyDecl(new_decl_index);
const ip = &mod.intern_pool;
const name = try ip.getOrPutStringFmt(mod.gpa, "{s}__anon_{d}", .{
// This protects the getOrPutStringFmt from reallocating src decl name while reading it.
try ip.string_bytes.ensureUnusedCapacity(mod.gpa, ip.stringToSlice(src_decl.name).len + 20);
const name = ip.getOrPutStringFmt(mod.gpa, "{s}__anon_{d}", .{
ip.stringToSlice(src_decl.name), @enumToInt(new_decl_index),
});
}) catch unreachable;
try mod.initNewAnonDecl(new_decl_index, src_decl.src_line, namespace, tv, name);
return new_decl_index;
}

5
src/Sema.zig
View File

@ -17065,6 +17065,7 @@ fn typeInfoNamespaceDecls(
seen_namespaces: *std.AutoHashMap(*Namespace, void),
) !void {
const mod = sema.mod;
const ip = &mod.intern_pool;
const gop = try seen_namespaces.getOrPut(namespace);
if (gop.found_existing) return;
const decls = namespace.decls.keys();
@ -17081,7 +17082,9 @@ fn typeInfoNamespaceDecls(
const name_val = v: {
var anon_decl = try block.startAnonDecl();
defer anon_decl.deinit();
const name = mod.intern_pool.stringToSlice(decl.name);
// Protects the decl name slice from being invalidated at the call to intern().
try ip.string_bytes.ensureUnusedCapacity(sema.gpa, ip.stringToSlice(decl.name).len + 1);
const name = ip.stringToSlice(decl.name);
const new_decl_ty = try mod.arrayType(.{
.len = name.len,
.child = .u8_type,