[dsymutil] Add -q/--quiet flag to suppress warnings (#91658)

Add a -q/--quiet flag to suppress dsymutil output. For now the flag is
limited to dsymutil, though there might be other places in the DWARF
linker that could be conditionalized by this flag.

The motivation is having a way to silence the "no debug symbols in
executable" warning. This is useful when we want to generate a dSYM for
a binary not containing debug symbols, but still want a dSYM that can be
indexed by spotlight.

rdar://127843467

llvm/docs/CommandGuide/dsymutil.rst

@@ -115,6 +115,10 @@ OPTIONS
  Specifies an alternate ``path`` to place the dSYM bundle. The default dSYM
  bundle path is created by appending ``.dSYM`` to the executable name.
 
+.. option:: -q, --quiet
+
+ Enable quiet mode and limit output.
+
 .. option:: --remarks-drop-without-debug
 
  Drop remarks without valid debug locations. Without this flags, all remarks are kept.

llvm/test/tools/dsymutil/ARM/empty-map.test

@@ -1,4 +1,5 @@
 # RUN: dsymutil -f -oso-prepend-path=%p/../Inputs -y %s -o - 2>&1 | FileCheck %s
+# RUN: dsymutil -q -f -oso-prepend-path=%p/../Inputs -y %s -o - 2>&1 | FileCheck %s --check-prefix QUIET
 
 # RUN: dsymutil --linker parallel -f -oso-prepend-path=%p/../Inputs -y %s -o - 2>&1 | FileCheck %s
 
@@ -7,3 +8,4 @@ triple:          'thumbv7-apple-darwin'
 ...
 
 # CHECK: warning: no debug symbols in executable (-arch armv7)
+# QUIET-NOT: no debug symbols in executable

llvm/test/tools/dsymutil/cmdline.test

@@ -23,6 +23,7 @@ CHECK: -object-prefix-map <prefix=remapped>
 CHECK: -oso-prepend-path <path>
 CHECK: -out <filename>
 CHECK: {{-o <filename>}}
+CHECK: -quiet
 CHECK: -remarks-drop-without-debug
 CHECK: -remarks-output-format <format>
 CHECK: -remarks-prepend-path <path>
@@ -46,3 +47,6 @@ NOINPUT: error: no input files specified
 
 RUN: dsymutil -bogus -help 2>&1 | FileCheck --check-prefix=BOGUS %s
 BOGUS: warning: ignoring unknown option: -bogus
+
+RUN: not dsymutil --quiet --verbose 2>&1 | FileCheck --check-prefix=CONFLICT %s
+CONFLICT: error: --quiet and --verbose cannot be specified together

llvm/tools/dsymutil/LinkUtils.h

@@ -38,6 +38,9 @@ struct LinkOptions {
   /// Verbosity
   bool Verbose = false;
 
+  /// Quiet
+  bool Quiet = false;
+
   /// Statistics
   bool Statistics = false;
 

llvm/tools/dsymutil/Options.td

@@ -24,6 +24,14 @@ def verbose: F<"verbose">,
   HelpText<"Enable verbose mode.">,
   Group<grp_general>;
 
+def quiet: F<"quiet">,
+  HelpText<"Enable quiet mode.">,
+  Group<grp_general>;
+def: Flag<["-"], "q">,
+  Alias<quiet>,
+  HelpText<"Alias for --quiet">,
+  Group<grp_general>;
+
 def keep_func_for_static: F<"keep-function-for-static">,
   HelpText<"Make a static variable keep the enclosing function even if it would have been omitted otherwise.">,
   Group<grp_general>;

llvm/tools/dsymutil/dsymutil.cpp

@@ -169,6 +169,12 @@ static Expected<std::vector<std::string>> getInputs(opt::InputArgList &Args,
 
 // Verify that the given combination of options makes sense.
 static Error verifyOptions(const DsymutilOptions &Options) {
+  if (Options.LinkOpts.Verbose && Options.LinkOpts.Quiet) {
+    return make_error<StringError>(
+        "--quiet and --verbose cannot be specified together",
+        errc::invalid_argument);
+  }
+
   if (Options.InputFiles.empty()) {
     return make_error<StringError>("no input files specified",
                                    errc::invalid_argument);
@@ -311,6 +317,7 @@ static Expected<DsymutilOptions> getOptions(opt::InputArgList &Args) {
   Options.LinkOpts.NoTimestamp = Args.hasArg(OPT_no_swiftmodule_timestamp);
   Options.LinkOpts.Update = Args.hasArg(OPT_update);
   Options.LinkOpts.Verbose = Args.hasArg(OPT_verbose);
+  Options.LinkOpts.Quiet = Args.hasArg(OPT_quiet);
   Options.LinkOpts.Statistics = Args.hasArg(OPT_statistics);
   Options.LinkOpts.Fat64 = Args.hasArg(OPT_fat64);
   Options.LinkOpts.KeepFunctionForStatic =
@@ -483,16 +490,20 @@ static bool verifyOutput(StringRef OutputFile, StringRef Arch,
                          DsymutilOptions Options, std::mutex &Mutex) {
 
   if (OutputFile == "-") {
-    std::lock_guard<std::mutex> Guard(Mutex);
-    WithColor::warning() << "verification skipped for " << Arch
-                         << " because writing to stdout.\n";
+    if (!Options.LinkOpts.Quiet) {
+      std::lock_guard<std::mutex> Guard(Mutex);
+      WithColor::warning() << "verification skipped for " << Arch
+                           << " because writing to stdout.\n";
+    }
     return true;
   }
 
   if (Options.LinkOpts.NoOutput) {
-    std::lock_guard<std::mutex> Guard(Mutex);
-    WithColor::warning() << "verification skipped for " << Arch
-                         << " because --no-output was passed.\n";
+    if (!Options.LinkOpts.Quiet) {
+      std::lock_guard<std::mutex> Guard(Mutex);
+      WithColor::warning() << "verification skipped for " << Arch
+                           << " because --no-output was passed.\n";
+    }
     return true;
   }
 
@@ -507,10 +518,12 @@ static bool verifyOutput(StringRef OutputFile, StringRef Arch,
   if (auto *Obj = dyn_cast<MachOObjectFile>(&Binary)) {
     std::unique_ptr<DWARFContext> DICtx = DWARFContext::create(*Obj);
     if (DICtx->getMaxVersion() > 5) {
-      std::lock_guard<std::mutex> Guard(Mutex);
-      WithColor::warning()
-          << "verification skipped for " << Arch
-          << " because DWARF standard greater than v5 is not supported yet.\n";
+      if (!Options.LinkOpts.Quiet) {
+        std::lock_guard<std::mutex> Guard(Mutex);
+        WithColor::warning() << "verification skipped for " << Arch
+                             << " because DWARF standard greater than v5 is "
+                                "not supported yet.\n";
+      }
       return true;
     }
 
@@ -751,11 +764,13 @@ int dsymutil_main(int argc, char **argv, const llvm::ToolContext &) {
           continue;
 
         if (Map->begin() == Map->end()) {
-          std::lock_guard<std::mutex> Guard(ErrorHandlerMutex);
-          WithColor::warning()
-              << "no debug symbols in executable (-arch "
-              << MachOUtils::getArchName(Map->getTriple().getArchName())
-              << ")\n";
+          if (!Options.LinkOpts.Quiet) {
+            std::lock_guard<std::mutex> Guard(ErrorHandlerMutex);
+            WithColor::warning()
+                << "no debug symbols in executable (-arch "
+                << MachOUtils::getArchName(Map->getTriple().getArchName())
+                << ")\n";
+          }
         }
 
         // Using a std::shared_ptr rather than std::unique_ptr because move-only