[lld] [lld][MachO] Respect dylibs linked with `-allowable_client` (PR #114638)
Carlo Cabrera via llvm-commits
llvm-commits at lists.llvm.org
Sat Nov 2 00:08:40 PDT 2024
https://github.com/carlocab updated https://github.com/llvm/llvm-project/pull/114638
>From 295308cdcd6343dffdbcee5b2acb2a5d8c3ac1fb Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <github at carlo.cab>
Date: Sat, 2 Nov 2024 12:13:11 +0800
Subject: [PATCH] [lld][MachO] Respect dylibs linked with `-allowable_client`
ld64.lld will currently allow you to link against dylibs linked with
`-allowable_client`, even if the client's name does not match any
allowed client.
This change fixes that. See #114146 for related discussion. It doesn't
quite fix that issue yet, but this change should enable fixing that
issue too, once lld learns how to parse the `allowable_clients` field in
`.tbd`s.
---
lld/MachO/Config.h | 1 +
lld/MachO/Driver.cpp | 40 +++++++++++++++++-
lld/MachO/InputFiles.cpp | 8 ++++
lld/MachO/InputFiles.h | 1 +
lld/MachO/Options.td | 3 +-
.../MachO/Inputs/liballowable_client.dylib | Bin 0 -> 16416 bytes
lld/test/MachO/allowable-client.s | 15 +++++++
7 files changed, 65 insertions(+), 3 deletions(-)
create mode 100755 lld/test/MachO/Inputs/liballowable_client.dylib
create mode 100644 lld/test/MachO/allowable-client.s
diff --git a/lld/MachO/Config.h b/lld/MachO/Config.h
index 8f6da6330d7ad4..41bcd58acc27f7 100644
--- a/lld/MachO/Config.h
+++ b/lld/MachO/Config.h
@@ -164,6 +164,7 @@ struct Configuration {
llvm::StringRef finalOutput;
llvm::StringRef installName;
+ llvm::StringRef clientName;
llvm::StringRef mapFile;
llvm::StringRef ltoObjPath;
llvm::StringRef thinLTOJobs;
diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
index ab4abb1fa97efc..ec655844b6781c 100644
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -407,8 +407,35 @@ static InputFile *addFile(StringRef path, LoadType loadType,
case file_magic::macho_dynamically_linked_shared_lib_stub:
case file_magic::tapi_file:
if (DylibFile *dylibFile =
- loadDylib(mbref, nullptr, /*isBundleLoader=*/false, isExplicit))
+ loadDylib(mbref, nullptr, /*isBundleLoader=*/false, isExplicit)) {
+ if (isExplicit && !dylibFile->allowedClients.empty()) {
+ bool allowed = false;
+
+ for (StringRef allowedClient : dylibFile->allowedClients) {
+ if (allowedClient == "!") {
+ allowed = false;
+ break;
+ }
+
+ // Not what you expect, but just as LD64 does it.
+ if (allowedClient.starts_with(config->clientName)) {
+ allowed = true;
+ }
+ }
+
+ // TODO: This behaviour doesn't quite match the latest available source
+ // release of LD64 (ld64-951.9), which allows "parents" and "siblings"
+ // to link to libraries even when they're not explicitly named as
+ // allowable clients. However, behaviour around this seems to have
+ // changed in the latest release of Xcode (ld64-1115.7.3), so it's not
+ // clear what the correct thing to do is yet.
+ if (!allowed)
+ error("cannot link directly with '" +
+ sys::path::filename(dylibFile->installName) + "' because " +
+ config->clientName + " is not an allowed client");
+ }
newFile = dylibFile;
+ }
break;
case file_magic::bitcode:
newFile = make<BitcodeFile>(mbref, "", 0, isLazy);
@@ -1863,6 +1890,17 @@ bool link(ArrayRef<const char *> argsArr, llvm::raw_ostream &stdoutOS,
config->installName = config->finalOutput;
}
+ auto getClientName = [&]() {
+ StringRef cn = path::filename(config->finalOutput);
+ cn.consume_front("lib");
+ auto firstDot = cn.find_first_of('.');
+ cn = cn.take_front(firstDot);
+ auto firstUnderscore = cn.find_first_of('_');
+ cn = cn.take_front(firstUnderscore);
+ return cn;
+ };
+ config->clientName = args.getLastArgValue(OPT_client_name, getClientName());
+
if (args.hasArg(OPT_mark_dead_strippable_dylib)) {
if (config->outputType != MH_DYLIB)
warn("-mark_dead_strippable_dylib: ignored, only has effect with -dylib");
diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
index 3086c9cc4729dd..6896138f88f508 100644
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -1730,6 +1730,14 @@ DylibFile::DylibFile(MemoryBufferRef mb, DylibFile *umbrella,
? this
: this->umbrella;
+ if (!canBeImplicitlyLinked) {
+ for (auto *cmd : findCommands<sub_client_command>(hdr, LC_SUB_CLIENT)) {
+ StringRef allowedClient{reinterpret_cast<const char *>(cmd) +
+ cmd->client};
+ allowedClients.push_back(allowedClient);
+ }
+ }
+
const auto *dyldInfo = findCommand<dyld_info_command>(hdr, LC_DYLD_INFO_ONLY);
const auto *exportsTrie =
findCommand<linkedit_data_command>(hdr, LC_DYLD_EXPORTS_TRIE);
diff --git a/lld/MachO/InputFiles.h b/lld/MachO/InputFiles.h
index 5e550c167c232e..63f60fe715d563 100644
--- a/lld/MachO/InputFiles.h
+++ b/lld/MachO/InputFiles.h
@@ -241,6 +241,7 @@ class DylibFile final : public InputFile {
DylibFile *exportingFile = nullptr;
DylibFile *umbrella;
SmallVector<StringRef, 2> rpaths;
+ SmallVector<StringRef> allowedClients;
uint32_t compatibilityVersion = 0;
uint32_t currentVersion = 0;
int64_t ordinal = 0; // Ordinal numbering starts from 1, so 0 is a sentinel
diff --git a/lld/MachO/Options.td b/lld/MachO/Options.td
index 70eb7c8b9e466b..739d1da15d4660 100644
--- a/lld/MachO/Options.td
+++ b/lld/MachO/Options.td
@@ -875,8 +875,7 @@ def allowable_client : Separate<["-"], "allowable_client">,
Group<grp_rare>;
def client_name : Separate<["-"], "client_name">,
MetaVarName<"<name>">,
- HelpText<"Specifies a <name> this client should match with the -allowable_client <name> in a dependent dylib">,
- Flags<[HelpHidden]>,
+ HelpText<"Specifies a <name> this client should match with the -allowable_client <name> in an explicitly linked dylib">,
Group<grp_rare>;
def umbrella : Separate<["-"], "umbrella">,
MetaVarName<"<name>">,
diff --git a/lld/test/MachO/Inputs/liballowable_client.dylib b/lld/test/MachO/Inputs/liballowable_client.dylib
new file mode 100755
index 0000000000000000000000000000000000000000..7c174a8a72a4c0972033660b129a8739f2aa4e3c
GIT binary patch
literal 16416
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literal 0
HcmV?d00001
diff --git a/lld/test/MachO/allowable-client.s b/lld/test/MachO/allowable-client.s
new file mode 100644
index 00000000000000..8d499d570fe80a
--- /dev/null
+++ b/lld/test/MachO/allowable-client.s
@@ -0,0 +1,15 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o
+# RUN: not %lld -o %t %t.o -L%S/Inputs -lallowable_client 2>&1 | FileCheck %s --check-prefix=NOTALLOWED1
+# RUN: not %lld -o %t %t.o -L%S/Inputs -lallowable_client -client_name notallowed 2>&1 | FileCheck %s --check-prefix=NOTALLOWED2
+# RUN: %lld -o %t %t.o -L%S/Inputs -lallowable_client -client_name allowed
+# RUN: %lld -o %t %t.o -L%S/Inputs -lallowable_client -client_name all
+
+# NOTALLOWED1: error: cannot link directly with 'liballowable_client.dylib' because {{.*}} is not an allowed client
+# NOTALLOWED2: error: cannot link directly with 'liballowable_client.dylib' because notallowed is not an allowed client
+
+.text
+.global _main
+_main:
+ mov $0, %rax
+ ret
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