Add flag -swift-async-framepointer=auto,never,always to control swift extended frame information emission

include/swift/AST/IRGenOptions.h

@@ -81,6 +81,12 @@ enum class IRGenEmbedMode : unsigned {
   EmbedBitcode
 };
 
+enum class SwiftAsyncFramePointerKind : unsigned {
+   Auto, // Choose Swift async extended frame info based on deployment target.
+   Always, // Unconditionally emit Swift async extended frame info.
+   Never,  // Don't emit Swift async extended frame info.
+};
+
 using clang::PointerAuthSchema;
 
 struct PointerAuthOptions : clang::PointerAuthOptions {
@@ -282,6 +288,8 @@ class IRGenOptions {
 
   IRGenLLVMLTOKind LLVMLTOKind : 2;
 
+  SwiftAsyncFramePointerKind SwiftAsyncFramePointer : 2;
+
   /// Add names to LLVM values.
   unsigned HasValueNamesSetting : 1;
   unsigned ValueNames : 1;
@@ -393,7 +401,9 @@ class IRGenOptions {
         Playground(false),
         EmitStackPromotionChecks(false), FunctionSections(false),
         PrintInlineTree(false), EmbedMode(IRGenEmbedMode::None),
-        LLVMLTOKind(IRGenLLVMLTOKind::None), HasValueNamesSetting(false),
+        LLVMLTOKind(IRGenLLVMLTOKind::None),
+        SwiftAsyncFramePointer(SwiftAsyncFramePointerKind::Always),
+        HasValueNamesSetting(false),
         ValueNames(false), EnableReflectionMetadata(true),
         EnableReflectionNames(true), EnableAnonymousContextMangledNames(false),
         ForcePublicLinkage(false), LazyInitializeClassMetadata(false),

include/swift/Option/FrontendOptions.td

@@ -806,6 +806,10 @@ def type_info_dump_filter_EQ : Joined<["-"], "type-info-dump-filter=">,
   Flags<[FrontendOption]>,
   HelpText<"One of 'all', 'resilient' or 'fragile'">;
 
+def swift_async_frame_pointer_EQ : Joined<["-"], "swift-async-frame-pointer=">,
+  Flags<[FrontendOption]>,
+  HelpText<"One of 'auto', 'always' or 'never'">;
+
 def previous_module_installname_map_file
   : Separate<["-"], "previous-module-installname-map-file">, MetaVarName<"<path>">,
     HelpText<"Path to a Json file indicating module name to installname map for @_originallyDefinedIn">;

lib/Frontend/CompilerInvocation.cpp

@@ -1908,6 +1908,26 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
     Opts.VirtualFunctionElimination = true;
   }
 
+  // Default to disabling swift async extended frame info on anything but
+  // darwin. Other platforms are unlikely to have support for extended frame
+  // pointer information.
+  if (!Triple.isOSDarwin()) {
+    Opts.SwiftAsyncFramePointer = SwiftAsyncFramePointerKind::Never;
+  }
+  if (const Arg *A = Args.getLastArg(OPT_swift_async_frame_pointer_EQ)) {
+    StringRef mode(A->getValue());
+    if (mode == "auto")
+      Opts.SwiftAsyncFramePointer = SwiftAsyncFramePointerKind::Auto;
+    else if (mode == "always")
+      Opts.SwiftAsyncFramePointer = SwiftAsyncFramePointerKind::Always;
+    else if (mode == "never")
+      Opts.SwiftAsyncFramePointer = SwiftAsyncFramePointerKind::Never;
+    else {
+      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
+                     A->getAsString(Args), A->getValue());
+    }
+  }
+
   return false;
 }
 

lib/IRGen/IRGen.cpp

@@ -180,6 +180,18 @@ swift::getIRTargetOptions(const IRGenOptions &Opts, ASTContext &Ctx) {
     TargetOpts.GlobalISelAbort = GlobalISelAbortMode::DisableWithDiag;
   }
 
+  switch (Opts.SwiftAsyncFramePointer) {
+  case SwiftAsyncFramePointerKind::Never:
+    TargetOpts.SwiftAsyncFramePointer = SwiftAsyncFramePointerMode::Never;
+    break;
+  case SwiftAsyncFramePointerKind::Auto:
+    TargetOpts.SwiftAsyncFramePointer = SwiftAsyncFramePointerMode::DeploymentBased;
+    break;
+  case SwiftAsyncFramePointerKind::Always:
+    TargetOpts.SwiftAsyncFramePointer = SwiftAsyncFramePointerMode::Always;
+    break;
+  }
+
   clang::TargetOptions &ClangOpts = Clang->getTargetInfo().getTargetOpts();
   return std::make_tuple(TargetOpts, ClangOpts.CPU, ClangOpts.Features, ClangOpts.Triple);
 }

stdlib/public/BackDeployConcurrency/CMakeLists.txt

@@ -46,5 +46,6 @@ set(swift_concurrency_options
 set(swift_concurrency_extra_sources
   "../BackDeployConcurrency/Exclusivity.cpp"
   "../BackDeployConcurrency/Metadata.cpp")
+set(swift_concurrency_async_fp_mode "never")
 
 add_subdirectory(../Concurrency stdlib/public/BackDeployConcurrency)

stdlib/public/Concurrency/CMakeLists.txt

@@ -31,6 +31,26 @@ if(SWIFT_CONCURRENCY_USES_DISPATCH)
   endif()
 endif()
 
+
+set(SWIFT_RUNTIME_CONCURRENCY_C_FLAGS)
+set(SWIFT_RUNTIME_CONCURRENCY_SWIFT_FLAGS)
+
+if(NOT swift_concurrency_async_fp_mode)
+  set(swift_concurrency_async_fp_mode "always")
+endif()
+
+# Don't emit extended frame info on platforms other than darwin, system
+# backtracer and system debugger are unlikely to support it.
+if(CMAKE_SYSTEM_NAME STREQUAL Darwin)
+  list(APPEND SWIFT_RUNTIME_CONCURRENCY_C_FLAGS
+    "-fswift-async-fp=${swift_concurrency_async_fp_mode}")
+  list(APPEND SWIFT_RUNTIME_CONCURRENCY_SWIFT_FLAGS
+    "-Xfrontend"
+    "-swift-async-frame-pointer=${swift_concurrency_async_fp_mode}")
+else()
+  list(APPEND SWIFT_RUNTIME_CONCURRENCY_C_FLAGS "-fswift-async-fp=never")
+endif()
+
 add_swift_target_library(swift_Concurrency ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   ../CompatibilityOverride/CompatibilityOverride.cpp
   Actor.cpp
@@ -91,13 +111,14 @@ add_swift_target_library(swift_Concurrency ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} I
   LINK_LIBRARIES ${swift_concurrency_link_libraries}
 
   C_COMPILE_FLAGS
-    -Dswift_Concurrency_EXPORTS
+    -Dswift_Concurrency_EXPORTS ${SWIFT_RUNTIME_CONCURRENCY_C_FLAGS}
   SWIFT_COMPILE_FLAGS
     ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
     -parse-stdlib
     -Xfrontend -enable-experimental-concurrency
     -Xfrontend -define-availability
     -Xfrontend "SwiftStdlib 5.5:macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0"
+    ${SWIFT_RUNTIME_CONCURRENCY_SWIFT_FLAGS}
   LINK_FLAGS "${SWIFT_RUNTIME_CONCURRENCY_SWIFT_LINK_FLAGS}"
   ${swift_concurrency_options}
   INSTALL_IN_COMPONENT ${swift_concurrency_install_component}

test/IRGen/swift_async_extended_frame_info.swift

@@ -0,0 +1,23 @@
+// RUN: %target-swift-frontend -disable-availability-checking -target x86_64-apple-macosx11 %s -S | %FileCheck  -check-prefix=ALWAYS %s
+// RUN: %target-swift-frontend -disable-availability-checking -target x86_64-apple-macosx12 %s -S | %FileCheck  -check-prefix=ALWAYS %s
+// RUN: %target-swift-frontend -disable-availability-checking -swift-async-frame-pointer=auto -target x86_64-apple-macosx11 %s -S | %FileCheck  -check-prefix=AUTO %s
+// RUN: %target-swift-frontend -disable-availability-checking -swift-async-frame-pointer=auto -target x86_64-apple-macosx12 %s -S | %FileCheck  -check-prefix=ALWAYS %s
+// RUN: %target-swift-frontend -disable-availability-checking -swift-async-frame-pointer=never -target x86_64-apple-macosx11 %s -S | %FileCheck  -check-prefix=NEVER %s
+// RUN: %target-swift-frontend -disable-availability-checking -swift-async-frame-pointer=never -target x86_64-apple-macosx12 %s -S | %FileCheck  -check-prefix=NEVER %s
+// RUN: %target-swift-frontend -disable-availability-checking -swift-async-frame-pointer=always -target x86_64-apple-macosx11 %s -S | %FileCheck  -check-prefix=ALWAYS %s
+// RUN: %target-swift-frontend -disable-availability-checking -swift-async-frame-pointer=always -target x86_64-apple-macosx12 %s -S | %FileCheck  -check-prefix=ALWAYS %s
+
+// REQUIRES: OS=macosx
+
+public func someAsyncFunction() async {
+}
+
+// AUTO: s31swift_async_extended_frame_info17someAsyncFunctionyyYaF:
+// AUTO:	_swift_async_extendedFramePointerFlags
+
+// ALWAYS: s31swift_async_extended_frame_info17someAsyncFunctionyyYaF:
+// ALWAYS: btsq	$60
+
+// NEVER: s31swift_async_extended_frame_info17someAsyncFunctionyyYaF:
+// NEVER-NOT:	_swift_async_extendedFramePointerFlags
+// NEVER-NOT: btsq	$60