[opt] Add new -enable-cmo-everything flag to enable serializing all sil, match serialization behavior of Embedded Swift.

include/swift/Option/Options.td

@@ -976,6 +976,11 @@ def EnbaleDefaultCMO : Flag<["-"], "enable-default-cmo">,
   Flags<[HelpHidden, FrontendOption]>,
   HelpText<"Perform conservative cross-module optimization">;
 
+def EnbaleCMOEverything : Flag<["-"], "enable-cmo-everything">,
+  Flags<[HelpHidden, FrontendOption]>,
+  HelpText<"Perform cross-module optimization on everything (all APIs). "
+           "This is the same level of serialization as Embedded Swift.">;
+
 def CrossModuleOptimization : Flag<["-"], "cross-module-optimization">,
   Flags<[HelpHidden, FrontendOption]>,
   HelpText<"Perform cross-module optimization">;

lib/Frontend/CompilerInvocation.cpp

@@ -2308,6 +2308,8 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
     Opts.CMOMode = CrossModuleOptimizationMode::Aggressive;
   } else if (Args.hasArg(OPT_EnbaleDefaultCMO)) {
     Opts.CMOMode = CrossModuleOptimizationMode::Default;  
+  } else if (Args.hasArg(OPT_EnbaleCMOEverything)) {
+    Opts.CMOMode = CrossModuleOptimizationMode::Everything;
   }
   Opts.EnableStackProtection =
       Args.hasFlag(OPT_enable_stack_protector, OPT_disable_stack_protector,

lib/FrontendTool/FrontendTool.cpp

@@ -1607,7 +1607,8 @@ static bool validateTBDIfNeeded(const CompilerInvocation &Invocation,
     }
 
     // Cross-module optimization does not support TBD.
-    if (Invocation.getSILOptions().CMOMode == CrossModuleOptimizationMode::Aggressive) {
+    if (Invocation.getSILOptions().CMOMode == CrossModuleOptimizationMode::Aggressive ||
+        Invocation.getSILOptions().CMOMode == CrossModuleOptimizationMode::Everything) {
       return false;
     }
 

test/SILOptimizer/cross-module-opt-everything.swift

@@ -0,0 +1,46 @@
+// RUN: %empty-directory(%t)
+// RUN: %{python} %utils/split_file.py -o %t %s
+
+// RUN: %target-swift-frontend -emit-module -o %t/Module.swiftmodule %t/Module.swift -experimental-performance-annotations -enable-cmo-everything -wmo
+// RUN: %target-swift-frontend -emit-ir %t/Main.swift -I%t -experimental-performance-annotations -enable-cmo-everything -wmo
+
+
+// REQUIRES: swift_in_compiler
+// REQUIRES: OS=macosx || OS=linux-gnu
+
+// BEGIN Module.swift
+
+@_semantics("optimize.no.crossmodule")
+private func bar<R>(count: Int, _ body: (UnsafeMutableBufferPointer<Int>) -> R) -> R {
+  let pointer = UnsafeMutablePointer<Int>(bitPattern: 42)!
+  let inoutBufferPointer = UnsafeMutableBufferPointer(start: pointer, count: count)
+  return body(inoutBufferPointer)
+}
+
+public func foo<R>(_ body: () -> R) -> R {
+  bar(count: 10) { p in
+    body()
+  }
+}
+
+public func module_func() {
+  foo {
+    return 0
+  }
+}
+
+// BEGIN Main.swift
+
+import Module
+
+@_noLocks
+public func test() {
+  module_func()
+}
+
+@_noLocks
+public func client_func() {
+  foo {
+    return 0
+  }
+}