Revert "[lld] enable fixup chains by default (llvm#79894)"

This caused links to fail with:

  lld/MachO/Symbols.cpp:97:
  virtual uint64_t lld::macho::Defined::getVA() const:
  Assertion `target->usesThunks()' failed.

or crash when asserts are disabled. See comment on
llvm#79894

> Enable chained fixups in lld when all platform and version criteria are
> met. This is an attempt at simplifying the logic used in ld 907:
>
> https://github.com/apple-oss-distributions/ld64/blob/93d74eafc37c0558b4ffb88a8bc15c17bed44a20/src/ld/Options.cpp#L5458-L5549
>
> Some changes were made to simplify the logic:
> - only enable chained fixups for macOS from 13.0 to avoid the arch check
> - only enable chained fixups for iphonesimulator from 16.0 to avoid the
> arch check
> - don't enable chained fixups for not specifically listed platforms
> - don't enable chained fixups for arm64_32

This reverts commit 775c285.

Author: zmodem

lld/MachO/Driver.cpp

@@ -49,7 +49,6 @@
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/TimeProfiler.h"
 #include "llvm/TargetParser/Host.h"
-#include "llvm/TextAPI/Architecture.h"
 #include "llvm/TextAPI/PackedVersion.h"
 
 #include <algorithm>
@@ -1043,53 +1042,41 @@ static bool shouldEmitChainedFixups(const InputArgList &args) {
   if (arg && arg->getOption().matches(OPT_no_fixup_chains))
     return false;
 
-  bool requested = arg && arg->getOption().matches(OPT_fixup_chains);
-  if (!config->isPic) {
-    if (requested)
-      error("-fixup_chains is incompatible with -no_pie");
+  bool isRequested = arg != nullptr;
 
-    return false;
+  // Version numbers taken from the Xcode 13.3 release notes.
+  static const std::array<std::pair<PlatformType, VersionTuple>, 4> minVersion =
+      {{{PLATFORM_MACOS, VersionTuple(11, 0)},
+        {PLATFORM_IOS, VersionTuple(13, 4)},
+        {PLATFORM_TVOS, VersionTuple(14, 0)},
+        {PLATFORM_WATCHOS, VersionTuple(7, 0)}}};
+  PlatformType platform = removeSimulator(config->platformInfo.target.Platform);
+  auto it = llvm::find_if(minVersion,
+                          [&](const auto &p) { return p.first == platform; });
+  if (it != minVersion.end() &&
+      it->second > config->platformInfo.target.MinDeployment) {
+    if (!isRequested)
+      return false;
+
+    warn("-fixup_chains requires " + getPlatformName(config->platform()) + " " +
+         it->second.getAsString() + ", which is newer than target minimum of " +
+         config->platformInfo.target.MinDeployment.getAsString());
   }
 
   if (!is_contained({AK_x86_64, AK_x86_64h, AK_arm64}, config->arch())) {
-    if (requested)
+    if (isRequested)
       error("-fixup_chains is only supported on x86_64 and arm64 targets");
-
     return false;
   }
 
-  if (args.hasArg(OPT_preload)) {
-    if (requested)
-      error("-fixup_chains is incompatible with -preload");
-
+  if (!config->isPic) {
+    if (isRequested)
+      error("-fixup_chains is incompatible with -no_pie");
     return false;
   }
 
-  if (requested)
-    return true;
-
-  static const std::array<std::pair<PlatformType, VersionTuple>, 7> minVersion =
-      {{
-          {PLATFORM_IOS, VersionTuple(13, 4)},
-          {PLATFORM_IOSSIMULATOR, VersionTuple(16, 0)},
-          {PLATFORM_MACOS, VersionTuple(13, 0)},
-          {PLATFORM_TVOS, VersionTuple(14, 0)},
-          {PLATFORM_TVOSSIMULATOR, VersionTuple(15, 0)},
-          {PLATFORM_WATCHOS, VersionTuple(7, 0)},
-          {PLATFORM_WATCHOSSIMULATOR, VersionTuple(8, 0)},
-      }};
-  PlatformType platform = config->platformInfo.target.Platform;
-  auto it = llvm::find_if(minVersion,
-                          [&](const auto &p) { return p.first == platform; });
-
-  // We don't know the versions for other platforms, so default to disabled.
-  if (it == minVersion.end())
-    return false;
-
-  if (it->second > config->platformInfo.target.MinDeployment)
-    return false;
-
-  return true;
+  // TODO: Enable by default once stable.
+  return isRequested;
 }
 
 void SymbolPatterns::clear() {

lld/test/MachO/arm64-32-stubs.s

@@ -10,7 +10,7 @@
 # RUN: llvm-mc -filetype=obj -triple=arm64_32-apple-watchos %t/test.s -o %t/test.o
 # RUN: %lld-watchos -dylib -install_name @executable_path/libfoo.dylib %t/foo.o -o %t/libfoo.dylib
 # RUN: %lld-watchos -dylib -install_name @executable_path/libbar.dylib %t/bar.o -o %t/libbar.dylib
-# RUN: %lld-watchos -lSystem %t/libfoo.dylib %t/libbar.dylib %t/test.o -o %t/test -no_fixup_chains
+# RUN: %lld-watchos -lSystem %t/libfoo.dylib %t/libbar.dylib %t/test.o -o %t/test
 
 # RUN: llvm-objdump --no-print-imm-hex --macho -d --no-show-raw-insn --section="__TEXT,__stubs" --section="__TEXT,__stub_helper" %t/test | FileCheck %s
 

lld/test/MachO/arm64-stubs.s

@@ -5,7 +5,7 @@
 # RUN: llvm-mc -filetype=obj -triple=arm64-apple-darwin %t/test.s -o %t/test.o
 # RUN: %lld -arch arm64 -dylib -install_name @executable_path/libfoo.dylib %t/foo.o -o %t/libfoo.dylib
 # RUN: %lld -arch arm64 -dylib -install_name @executable_path/libbar.dylib %t/bar.o -o %t/libbar.dylib
-# RUN: %lld -arch arm64 -lSystem %t/libfoo.dylib %t/libbar.dylib %t/test.o -o %t/test -no_fixup_chains
+# RUN: %lld -arch arm64 -lSystem %t/libfoo.dylib %t/libbar.dylib %t/test.o -o %t/test
 
 # RUN: llvm-objdump --no-print-imm-hex --macho -d --no-show-raw-insn --section="__TEXT,__stubs" --section="__TEXT,__stub_helper" %t/test | FileCheck %s
 

lld/test/MachO/dyld-stub-binder.s

@@ -14,27 +14,27 @@
 # RUN: %lld -arch arm64 -lSystem -dylib %t/foo.o -o %t/libfoo.dylib
 # RUN: llvm-nm -m %t/libfoo.dylib | FileCheck --check-prefix=STUB %s
 
+
 ## Dylibs that do lazy dynamic calls do need dyld_stub_binder.
 # RUN: not %no-lsystem-lld -arch arm64 -dylib %t/bar.o %t/libfoo.dylib \
-# RUN:     -o %t/libbar.dylib -no_fixup_chains 2>&1 | \
-# RUN:     FileCheck --check-prefix=MISSINGSTUB %s
+# RUN:     -o %t/libbar.dylib 2>&1 | FileCheck --check-prefix=MISSINGSTUB %s
 # RUN: %lld -arch arm64 -lSystem -dylib %t/bar.o  %t/libfoo.dylib \
-# RUN:     -o %t/libbar.dylib -no_fixup_chains
+# RUN:     -o %t/libbar.dylib
 # RUN: llvm-nm -m %t/libbar.dylib | FileCheck --check-prefix=STUB %s
 
 ## As do executables.
 # RUN: not %no-lsystem-lld -arch arm64 %t/libfoo.dylib %t/libbar.dylib %t/test.o \
-# RUN:     -o %t/test -no_fixup_chains 2>&1 | FileCheck --check-prefix=MISSINGSTUB %s
+# RUN:     -o %t/test 2>&1 | FileCheck --check-prefix=MISSINGSTUB %s
 # RUN: %lld -arch arm64 -lSystem %t/libfoo.dylib %t/libbar.dylib %t/test.o \
-# RUN:     -o %t/test -no_fixup_chains
+# RUN:     -o %t/test
 # RUN: llvm-nm -m %t/test | FileCheck --check-prefix=STUB %s
 
 ## Test dynamic lookup of dyld_stub_binder.
 # RUN: %no-lsystem-lld -arch arm64 %t/libfoo.dylib %t/libbar.dylib %t/test.o \
-# RUN:     -o %t/test -undefined dynamic_lookup -no_fixup_chains
+# RUN:     -o %t/test -undefined dynamic_lookup
 # RUN: llvm-nm -m %t/test | FileCheck --check-prefix=DYNSTUB %s
 # RUN: %no-lsystem-lld -arch arm64 %t/libfoo.dylib %t/libbar.dylib %t/test.o \
-# RUN:     -o %t/test -U dyld_stub_binder -no_fixup_chains
+# RUN:     -o %t/test -U dyld_stub_binder
 # RUN: llvm-nm -m %t/test | FileCheck --check-prefix=DYNSTUB %s
 
 # MISSINGSTUB:      error: undefined symbol: dyld_stub_binder

lld/test/MachO/icf-safe.ll

@@ -3,14 +3,14 @@
 ; RUN: rm -rf %t; mkdir %t
 
 ; RUN: llc -filetype=obj %s -O3 -o %t/icf-obj.o -enable-machine-outliner=never -mtriple arm64-apple-macos -addrsig
-; RUN: %lld -arch arm64 -lSystem --icf=safe -dylib -o %t/icf-safe.dylib %t/icf-obj.o -no_fixup_chains
-; RUN: %lld -arch arm64 -lSystem --icf=all  -dylib -o %t/icf-all.dylib  %t/icf-obj.o -no_fixup_chains
+; RUN: %lld -arch arm64 -lSystem --icf=safe -dylib -o %t/icf-safe.dylib %t/icf-obj.o
+; RUN: %lld -arch arm64 -lSystem --icf=all  -dylib -o %t/icf-all.dylib  %t/icf-obj.o
 ; RUN: llvm-objdump %t/icf-safe.dylib -d --macho | FileCheck %s --check-prefix=ICFSAFE
 ; RUN: llvm-objdump %t/icf-all.dylib  -d --macho | FileCheck %s --check-prefix=ICFALL
 
 ; RUN: llvm-as %s -o %t/icf-bitcode.o
-; RUN: %lld -arch arm64 -lSystem --icf=safe -dylib -o %t/icf-safe-bitcode.dylib %t/icf-bitcode.o -no_fixup_chains
-; RUN: %lld -arch arm64 -lSystem --icf=all  -dylib -o %t/icf-all-bitcode.dylib %t/icf-bitcode.o -no_fixup_chains
+; RUN: %lld -arch arm64 -lSystem --icf=safe -dylib -o %t/icf-safe-bitcode.dylib %t/icf-bitcode.o
+; RUN: %lld -arch arm64 -lSystem --icf=all  -dylib -o %t/icf-all-bitcode.dylib %t/icf-bitcode.o
 ; RUN: llvm-objdump %t/icf-safe-bitcode.dylib -d --macho | FileCheck %s --check-prefix=ICFSAFE
 ; RUN: llvm-objdump %t/icf-all-bitcode.dylib  -d --macho | FileCheck %s --check-prefix=ICFALL
 

lld/test/MachO/invalid/chained-fixups-incompatible.s

@@ -2,13 +2,17 @@
 # RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %s -o %t.o
 # RUN: not %lld -lSystem -no_pie -fixup_chains %t.o -o /dev/null 2>&1 | \
 # RUN:   FileCheck %s --check-prefix=NO-PIE
+# RUN: %no-fatal-warnings-lld -fixup_chains %t.o -o /dev/null \
+# RUN:   -lSystem -platform_version macos 10.15 10.15 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=VERSION
 # RUN: llvm-mc -filetype=obj -triple=arm64_32-apple-darwin %s -o %t-arm64_32.o
 # RUN: not %lld-watchos -lSystem -fixup_chains %t-arm64_32.o -o /dev/null 2>&1 | \
 # RUN:   FileCheck %s --check-prefix=ARCH
 
 ## Check that we emit diagnostics when -fixup_chains is explicitly specified,
 ## but we don't support creating chained fixups for said configuration.
 # NO-PIE:  error: -fixup_chains is incompatible with -no_pie
+# VERSION: warning: -fixup_chains requires macOS 11.0, which is newer than target minimum of 10.15
 # ARCH:    error: -fixup_chains is only supported on x86_64 and arm64 targets
 
 .globl _main

lld/test/MachO/objc-selrefs.s

@@ -6,14 +6,14 @@
 # RUN: llvm-mc -filetype=obj -triple=arm64-apple-darwin %t/implicit-selrefs.s -o %t/implicit-selrefs.o
 
 # RUN: %lld -dylib -arch arm64 -lSystem -o %t/explicit-only-no-icf \
-# RUN:   %t/explicit-selrefs-1.o %t/explicit-selrefs-2.o -no_fixup_chains
+# RUN:   %t/explicit-selrefs-1.o %t/explicit-selrefs-2.o
 # RUN: llvm-otool -vs __DATA __objc_selrefs %t/explicit-only-no-icf | \
 # RUN:   FileCheck %s --check-prefix=EXPLICIT-NO-ICF
 
 ## NOTE: ld64 always dedups the selrefs unconditionally, but we only do it when
 ## ICF is enabled.
 # RUN: %lld -dylib -arch arm64 -lSystem -o %t/explicit-only-with-icf \
-# RUN:   %t/explicit-selrefs-1.o %t/explicit-selrefs-2.o -no_fixup_chains
+# RUN:   %t/explicit-selrefs-1.o %t/explicit-selrefs-2.o
 # RUN: llvm-otool -vs __DATA __objc_selrefs %t/explicit-only-with-icf \
 # RUN:   | FileCheck %s --check-prefix=EXPLICIT-WITH-ICF
 
@@ -25,8 +25,7 @@
 # SELREFS-EMPTY:
 
 # RUN: %lld -dylib -arch arm64 -lSystem --icf=all -o %t/explicit-and-implicit \
-# RUN:   %t/explicit-selrefs-1.o %t/explicit-selrefs-2.o %t/implicit-selrefs.o \
-# RUN:   -no_fixup_chains
+# RUN:   %t/explicit-selrefs-1.o %t/explicit-selrefs-2.o %t/implicit-selrefs.o
 # RUN: llvm-otool -vs __DATA __objc_selrefs %t/explicit-and-implicit \
 # RUN:   | FileCheck %s --check-prefix=EXPLICIT-AND-IMPLICIT