[lld] [lld][MachO] Respect dylibs linked with `-allowable_client` (PR #114638)

Carlo Cabrera via llvm-commits llvm-commits at lists.llvm.org
Mon Nov 4 04:14:36 PST 2024


https://github.com/carlocab updated https://github.com/llvm/llvm-project/pull/114638

>From 198f70aed7ffbf4ba45e180df7bb10b4262e6aa8 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 1/2] [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                          |  31 +++++++++++++++++-
 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, 56 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 8f6da6330d7ad47..41bcd58acc27f7d 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 ab4abb1fa97efc8..6fe002aa91fa559 100644
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -407,8 +407,28 @@ 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->allowableClients.empty()) {
+        bool allowed = std::any_of(
+            dylibFile->allowableClients.begin(),
+            dylibFile->allowableClients.end(), [&](StringRef allowableClient) {
+              // Not what you expect, but exactly as LD64 does.
+              return allowableClient.starts_with(config->clientName);
+            });
+
+        // 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 +1883,15 @@ 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 firstDotOrUnderscore = cn.find_first_of("._");
+    cn = cn.take_front(firstDotOrUnderscore);
+    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 3086c9cc4729dd8..c715169927e7be2 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 allowableClient{reinterpret_cast<const char *>(cmd) +
+                                cmd->client};
+      allowableClients.push_back(allowableClient);
+    }
+  }
+
   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 5e550c167c232e1..bc8c8038a39d182 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> allowableClients;
   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 70eb7c8b9e466b2..739d1da15d4660f 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 000000000000000..8d499d570fe80a8
--- /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

>From 02ea5fd487b8ff1abc13e4756768ffcd420a4ff0 Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <github at carlo.cab>
Date: Sun, 3 Nov 2024 13:34:03 +0800
Subject: [PATCH 2/2] [lld][MachO] Respect `allowable-clients` field in `.tbd`s

Closes #114146.
---
 lld/MachO/InputFiles.cpp          |  6 +++
 lld/test/MachO/allowable-client.s | 77 +++++++++++++++++++++++++++----
 2 files changed, 74 insertions(+), 9 deletions(-)

diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
index c715169927e7be2..c3f7c434ffca142 100644
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -1899,6 +1899,12 @@ DylibFile::DylibFile(const InterfaceFile &interface, DylibFile *umbrella,
   exportingFile = (canBeImplicitlyLinked && isImplicitlyLinked(installName))
                       ? this
                       : umbrella;
+
+  if (!canBeImplicitlyLinked)
+    for (const auto &allowableClient : interface.allowableClients())
+      allowableClients.push_back(
+          *make<std::string>(allowableClient.getInstallName().data()));
+
   auto addSymbol = [&](const llvm::MachO::Symbol &symbol,
                        const Twine &name) -> void {
     StringRef savedName = saver().save(name);
diff --git a/lld/test/MachO/allowable-client.s b/lld/test/MachO/allowable-client.s
index 8d499d570fe80a8..3341dc59c1d8117 100644
--- a/lld/test/MachO/allowable-client.s
+++ b/lld/test/MachO/allowable-client.s
@@ -1,15 +1,74 @@
 # 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
+# RUN: rm -rf %t; split-file %s %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/test.s -o %t/test.o
 
-# 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
+# Check linking against a .dylib
+# RUN: not %lld -o %t/test %t/test.o -L%S/Inputs -lallowable_client 2>&1 | FileCheck %s --check-prefix=NOTALLOWED-IMPLICIT
+# RUN: not %lld -o %t/libtest_debug.exe %t/test.o -L%S/Inputs -lallowable_client 2>&1 | FileCheck %s --check-prefix=NOTALLOWED-IMPLICIT
+# RUN: not %lld -o %t/test %t/test.o -L%S/Inputs -lallowable_client -client_name notallowed 2>&1 | FileCheck %s --check-prefix=NOTALLOWED-EXPLICIT
+# RUN: %lld -o %t/test %t/test.o -L%S/Inputs -lallowable_client -client_name allowed
+# RUN: %lld -o %t/test %t/test.o -L%S/Inputs -lallowable_client -client_name all
+# RUN: %lld -o %t/all %t/test.o -L%S/Inputs -lallowable_client
+# RUN: %lld -o %t/allowed %t/test.o -L%S/Inputs -lallowable_client
+# RUN: %lld -o %t/liballowed_debug.exe %t/test.o -L%S/Inputs -lallowable_client
 
+# Check linking against a .tbd
+# RUN: not %lld -o %t/test %t/test.o -L%t -lallowable_client 2>&1 | FileCheck %s --check-prefix=NOTALLOWED-IMPLICIT
+# RUN: not %lld -o %t/libtest_debug.exe %t/test.o -L%t -lallowable_client 2>&1 | FileCheck %s --check-prefix=NOTALLOWED-IMPLICIT
+# RUN: not %lld -o %t/test %t/test.o -L%t -lallowable_client -client_name notallowed 2>&1 | FileCheck %s --check-prefix=NOTALLOWED-EXPLICIT
+# RUN: %lld -o %t/test %t/test.o -L%t -lallowable_client -client_name allowed
+# RUN: %lld -o %t/test %t/test.o -L%t -lallowable_client -client_name all
+# RUN: %lld -o %t/all %t/test.o -L%t -lallowable_client
+# RUN: %lld -o %t/allowed %t/test.o -L%t -lallowable_client
+# RUN: %lld -o %t/liballowed_debug.exe %t/test.o -L%t -lallowable_client
+
+# NOTALLOWED-IMPLICIT: error: cannot link directly with 'liballowable_client.dylib' because test is not an allowed client
+# NOTALLOWED-EXPLICIT: error: cannot link directly with 'liballowable_client.dylib' because notallowed is not an allowed client
+
+#--- test.s
 .text
-.global _main
+.globl _main
 _main:
-  mov $0, %rax
   ret
+
+#--- liballowable_client.tbd
+{
+  "main_library": {
+    "allowable_clients": [
+      {
+        "clients": [
+          "allowed"
+        ]
+      }
+    ],
+    "compatibility_versions": [
+      {
+        "version": "0"
+      }
+    ],
+    "current_versions": [
+      {
+        "version": "0"
+      }
+    ],
+    "flags": [
+      {
+        "attributes": [
+          "not_app_extension_safe"
+        ]
+      }
+    ],
+    "install_names": [
+      {
+        "name": "lib/liballowable_client.dylib"
+      }
+    ],
+    "target_info": [
+      {
+        "min_deployment": "10.11",
+        "target": "x86_64-macos"
+      }
+    ]
+  },
+  "tapi_tbd_version": 5
+}



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