[TBDGen] Ensure symbols listed include maccatalyst when library is built (#67160)

zippered.

This also introduces a dependency on new testing tool
llvm-tapi-diff. This allows for a structural difference check on tbd
files.

resolves: rdar://107368040

Author: cyndyishida

lib/IRGen/TBDGen.cpp

@@ -606,13 +606,14 @@ TBDFile GenerateTBDRequest::evaluate(Evaluator &evaluator,
 
   llvm::MachO::Target target(ctx.LangOpts.Target);
   file.addTarget(target);
+  llvm::MachO::TargetList targets{target};
   // Add target variant
   if (ctx.LangOpts.TargetVariant.has_value()) {
     llvm::MachO::Target targetVar(*ctx.LangOpts.TargetVariant);
     file.addTarget(targetVar);
+    targets.push_back(targetVar);
   }
 
-  llvm::MachO::TargetList targets{target};
   auto addSymbol = [&](StringRef symbol, SymbolKind kind, SymbolSource source) {
     file.addSymbol(kind, symbol, targets);
   };

test/CMakeLists.txt

@@ -92,6 +92,7 @@ function(get_test_dependencies SDK result_var_name)
       llvm-readobj
       llvm-size
       llvm-strings
+      llvm-tapi-diff
       not
       split-file)
   endif()

test/TBD/zippered.swift

@@ -0,0 +1,25 @@
+// REQUIRES: OS=macosx
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %swift -target arm64-apple-macos13.0 -target-variant arm64-apple-ios16.0-macabi -typecheck -parse-as-library %t/test.swift -emit-tbd -emit-tbd-path %t/zippered.tbd
+// RUN: %llvm-tapi-diff %t/zippered.tbd %t/expected.tbd
+
+//--- test.swift
+public func foo() -> Bool {
+    return true
+}
+
+//--- expected.tbd
+--- !tapi-tbd
+tbd-version:     4
+targets:         [ arm64-macos, arm64-maccatalyst ]
+flags:           [ not_app_extension_safe ]
+install-name:    ''
+current-version: 0
+compatibility-version: 0
+swift-abi-version: 7
+exports:
+  - targets:         [ arm64-macos, arm64-maccatalyst ]
+    symbols:         [ '_$s4test3fooSbyF' ]
+...

test/lit.cfg

@@ -337,6 +337,7 @@ config.llvm_dwarfdump = inferSwiftBinary('llvm-dwarfdump')
 config.llvm_readelf = inferSwiftBinary('llvm-readelf')
 config.llvm_dis = inferSwiftBinary('llvm-dis')
 config.llvm_nm = inferSwiftBinary('llvm-nm')
+config.llvm_tapi_diff = inferSwiftBinary('llvm-tapi-diff')
 config.llvm_size = inferSwiftBinary('llvm-size')
 config.sourcekitd_test = inferSwiftBinary('sourcekitd-test')
 config.complete_test = inferSwiftBinary('complete-test')
@@ -604,6 +605,7 @@ config.substitutions.append( ('%llvm-dwarfdump', config.llvm_dwarfdump) )
 config.substitutions.append( ('%llvm-readelf', config.llvm_readelf) )
 config.substitutions.append( ('%llvm-dis', config.llvm_dis) )
 config.substitutions.append( ('%llvm-nm', config.llvm_nm) )
+config.substitutions.append( ('%llvm-tapi-diff', config.llvm_tapi_diff) )
 config.substitutions.append( ('%llvm-size', config.llvm_size) )
 config.substitutions.append( ('%swift-demangle-yamldump', config.swift_demangle_yamldump) )
 config.substitutions.append( ('%swift-demangle', config.swift_demangle) )