Remove dependency of SILFunction in IRGenOptions

SILFunction::shouldBePreservedForDebugger checks if some optimizations
are enabled to decide whether a function should be preserved so its
accessible form the debugger or not. Some of these settings used to live
only in IRGenOptions making SILFunction depend on IRGenOptions.

Author: augusto2112

include/swift/AST/SILOptions.h

@@ -305,6 +305,10 @@ class SILOptions {
   /// The format used for serializing remarks (default: YAML)
   llvm::remarks::Format OptRecordFormat = llvm::remarks::Format::YAML;
 
+  /// Are there any options that indicate that functions should not be preserved
+  /// for the debugger?
+  bool ShouldFunctionsBePreservedToDebugger = true;
+
   SILOptions() {}
 
   /// Return a hash code of any components from these options that should

lib/Frontend/CompilerInvocation.cpp

@@ -2203,6 +2203,22 @@ void parseExclusivityEnforcementOptions(const llvm::opt::Arg *A,
   }
 }
 
+static std::optional<IRGenLLVMLTOKind>
+ParseLLVMLTOKind(const ArgList &Args, DiagnosticEngine &Diags) {
+  std::optional<IRGenLLVMLTOKind> LLVMLTOKind;
+  if (const Arg *A = Args.getLastArg(options::OPT_lto)) {
+    LLVMLTOKind =
+        llvm::StringSwitch<std::optional<IRGenLLVMLTOKind>>(A->getValue())
+            .Case("llvm-thin", IRGenLLVMLTOKind::Thin)
+            .Case("llvm-full", IRGenLLVMLTOKind::Full)
+            .Default(std::nullopt);
+    if (!LLVMLTOKind)
+      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
+                     A->getAsString(Args), A->getValue());
+  }
+  return LLVMLTOKind;
+}
+
 static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
                          IRGenOptions &IRGenOpts, const FrontendOptions &FEOpts,
                          const TypeCheckerOptions &TCOpts,
@@ -2603,6 +2619,16 @@ static bool ParseSILArgs(SILOptions &Opts, ArgList &Args,
   Opts.EnableExperimentalSwiftBasedClosureSpecialization = 
       Args.hasArg(OPT_enable_experimental_swift_based_closure_specialization);
 
+  // If these optimizations are enabled never preserve functions for the
+  // debugger.
+  Opts.ShouldFunctionsBePreservedToDebugger =
+      !Args.hasArg(OPT_enable_llvm_wme);
+  Opts.ShouldFunctionsBePreservedToDebugger &=
+      !Args.hasArg(OPT_enable_llvm_vfe);
+  if (auto LTOKind = ParseLLVMLTOKind(Args, Diags))
+    Opts.ShouldFunctionsBePreservedToDebugger &=
+        LTOKind.value() == IRGenLLVMLTOKind::None;
+
   return false;
 }
 
@@ -2949,18 +2975,8 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
     }
   }
 
-  if (const Arg *A = Args.getLastArg(options::OPT_lto)) {
-    auto LLVMLTOKind =
-        llvm::StringSwitch<std::optional<IRGenLLVMLTOKind>>(A->getValue())
-            .Case("llvm-thin", IRGenLLVMLTOKind::Thin)
-            .Case("llvm-full", IRGenLLVMLTOKind::Full)
-            .Default(std::nullopt);
-    if (LLVMLTOKind)
-      Opts.LLVMLTOKind = LLVMLTOKind.value();
-    else
-      Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
-                     A->getAsString(Args), A->getValue());
-  }
+  if (auto LTOKind = ParseLLVMLTOKind(Args, Diags))
+     Opts.LLVMLTOKind = LTOKind.value();
 
   if (const Arg *A = Args.getLastArg(options::OPT_sanitize_coverage_EQ)) {
     Opts.SanitizeCoverage =

lib/SIL/IR/SILFunction.cpp

@@ -16,7 +16,6 @@
 #include "swift/AST/Availability.h"
 #include "swift/AST/Expr.h"
 #include "swift/AST/GenericEnvironment.h"
-#include "swift/AST/IRGenOptions.h"
 #include "swift/AST/LocalArchetypeRequirementCollector.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/Stmt.h"
@@ -999,16 +998,11 @@ bool SILFunction::shouldBePreservedForDebugger() const {
   if (getEffectiveOptimizationMode() != OptimizationMode::NoOptimization)
     return false;
 
-  if (getModule().getASTContext().LangOpts.hasFeature(Feature::Embedded))
+  if (!getModule().getOptions().ShouldFunctionsBePreservedToDebugger)
     return false;
 
-  if (const IRGenOptions *options = getModule().getIRGenOptionsOrNull()) {
-    if (options->WitnessMethodElimination ||
-        options->VirtualFunctionElimination ||
-        options->LLVMLTOKind != IRGenLLVMLTOKind::None) {
-      return false;
-    }
-  }
+  if (getModule().getASTContext().LangOpts.hasFeature(Feature::Embedded))
+    return false;
 
   if (isAvailableExternally())
     return false;