[MachO] Use error instead of fatal for missing -arch

`fatal` should only be used for malformed inputs according to
ErrorHandler.h; `error` is more appropriate for missing arguments,
accompanied by a check to bail out early in case of the error. Some
tests need to be adjusted accordingly.

Makes `lld/test/MachO/arch.s` pass with `LLD_IN_TEST=2`.

Reviewed By: #lld-macho, int3

Differential Revision: https://reviews.llvm.org/D112879

Author: smeenai

lld/MachO/Driver.cpp

@@ -659,10 +659,12 @@ static PlatformKind parsePlatformVersion(const ArgList &args) {
 // Has the side-effect of setting Config::target.
 static TargetInfo *createTargetInfo(InputArgList &args) {
   StringRef archName = args.getLastArgValue(OPT_arch);
-  if (archName.empty())
-    fatal("must specify -arch");
-  PlatformKind platform = parsePlatformVersion(args);
+  if (archName.empty()) {
+    error("must specify -arch");
+    return nullptr;
+  }
 
+  PlatformKind platform = parsePlatformVersion(args);
   config->platformInfo.target =
       MachO::Target(getArchitectureFromName(archName), platform);
 
@@ -680,7 +682,8 @@ static TargetInfo *createTargetInfo(InputArgList &args) {
   case CPU_TYPE_ARM:
     return createARMTargetInfo(cpuSubtype);
   default:
-    fatal("missing or unsupported -arch " + archName);
+    error("missing or unsupported -arch " + archName);
+    return nullptr;
   }
 }
 
@@ -1118,6 +1121,8 @@ bool macho::link(ArrayRef<const char *> argsArr, bool canExitEarly,
   target = createTargetInfo(args);
   depTracker =
       make<DependencyTracker>(args.getLastArgValue(OPT_dependency_info));
+  if (errorCount())
+    return false;
 
   config->osoPrefix = args.getLastArgValue(OPT_oso_prefix);
   if (!config->osoPrefix.empty()) {

lld/test/MachO/color-diagnostics.test

@@ -1,12 +1,11 @@
 # Windows command prompt doesn't support ANSI escape sequences.
 # REQUIRES: shell
 
-# RUN: not %lld -xyz --color-diagnostics /nosuchfile 2>&1 \
+# RUN: not %lld --color-diagnostics /nosuchfile 2>&1 \
 # RUN:   | FileCheck -check-prefix=COLOR %s
-# RUN: not %lld -xyz --color-diagnostics=always /nosuchfile 2>&1 \
+# RUN: not %lld --color-diagnostics=always /nosuchfile 2>&1 \
 # RUN:   | FileCheck -check-prefix=COLOR %s
 
-# COLOR: {{lld: .\[0;31merror: .\[0munknown argument '-xyz'}}
 # COLOR: {{lld: .\[0;31merror: .\[0mcannot open /nosuchfile}}
 
 # RUN: not %lld --color-diagnostics=foobar 2>&1 | FileCheck -check-prefix=ERR %s

lld/test/MachO/driver.test

@@ -3,5 +3,4 @@ VERSION: LLD
 
 # RUN: not %lld ---help 2>&1 | FileCheck -check-prefix=SPELLHELP %s
 SPELLHELP: error: unknown argument '---help', did you mean '--help'
-# FIXME: This should say "no input files" instead
-SPELLHELP: error: undefined symbol: _main
+# FIXME: We should also output a "no input files" error

lld/test/MachO/search-paths-darwin.test

@@ -3,7 +3,7 @@ REQUIRES: system-darwin
 
 RUN: mkdir -p %t1 %t2
 
-RUN: not ld64.lld -arch x86_64 -v -L%t1 -F%t2 2>&1 | FileCheck -DLDIR=%t1 -DFDIR=%t2 %s
+RUN: not ld64.lld -arch x86_64 -platform_version macos 10.5 11.0 -v -L%t1 -F%t2 2>&1 | FileCheck -DLDIR=%t1 -DFDIR=%t2 %s
 CHECK:      Library search paths:
 CHECK-NEXT: [[LDIR]]
 CHECK-NEXT: /usr/lib
@@ -12,7 +12,7 @@ CHECK-NEXT: [[FDIR]]
 CHECK-NEXT: /Library/Frameworks
 CHECK-NEXT: /System/Library/Frameworks
 
-RUN: not ld64.lld -arch x86_64 -v -L%t1 -F%t2 -Z 2>&1 | FileCheck -DLDIR=%t1 -DFDIR=%t2 --check-prefix=CHECK_Z %s
+RUN: not ld64.lld -arch x86_64 -platform_version macos 10.5 11.0 -v -L%t1 -F%t2 -Z 2>&1 | FileCheck -DLDIR=%t1 -DFDIR=%t2 --check-prefix=CHECK_Z %s
 CHECK_Z:      Library search paths:
 CHECK_Z-NEXT: [[LDIR]]
 CHECK_Z-NEXT: Framework search paths: