Merge pull request #17172 from jckarter/jit-relative-references-4.2

[4.2] IRGen: More specifically curtail JIT use of relative references to the integrated REPL.

Author: jckarter

include/swift/AST/IRGenOptions.h

@@ -103,6 +103,9 @@ class IRGenOptions {
   /// \brief Whether we're generating IR for the JIT.
   unsigned UseJIT : 1;
 
+  /// \brief Whether we're generating code for the integrated REPL.
+  unsigned IntegratedREPL : 1;
+  
   /// \brief Whether we should run LLVM optimizations after IRGen.
   unsigned DisableLLVMOptzns : 1;
 
@@ -182,6 +185,7 @@ class IRGenOptions {
         Verify(true), OptMode(OptimizationMode::NotSet),
         Sanitizers(OptionSet<SanitizerKind>()),
         DebugInfoKind(IRGenDebugInfoKind::None), UseJIT(false),
+        IntegratedREPL(false),
         DisableLLVMOptzns(false), DisableSwiftSpecificLLVMOptzns(false),
         DisableLLVMSLPVectorizer(false), DisableFPElim(true), Playground(false),
         EmitStackPromotionChecks(false), PrintInlineTree(false),

lib/IRGen/GenDecl.cpp

@@ -2580,12 +2580,12 @@ IRGenModule::getAddrOfLLVMVariableOrGOTEquivalent(LinkEntity entity,
   // binary, then we ought to be able to directly relative-reference the
   // symbol. However, some platforms don't have the necessary relocations to
   // represent a relative reference to an undefined symbol, so conservatively
-  // produce an indirect reference in this case. Also, some JIT modes
-  // incrementally add new definitions that refer back to existing ones
+  // produce an indirect reference in this case. Also, the integrated REPL
+  // incrementally adds new definitions that refer back to existing ones
   // relatively, so always use indirect references in this situation.
   auto entry = GlobalVars[entity];
   if (forceIndirectness == ConstantReference::Direct &&
-      !IRGen.Opts.UseJIT &&
+      !IRGen.Opts.IntegratedREPL &&
       (!entity.isAvailableExternally(*this) || isDefinition(entry))) {
     // FIXME: Relative references to aliases break MC on 32-bit Mach-O
     // platforms (rdar://problem/22450593 ), so substitute an alias with its

lib/IRGen/IRGenMangler.cpp

@@ -92,7 +92,7 @@ IRGenMangler::mangleTypeForReflection(IRGenModule &IGM,
 
   if (IGM.CurSourceFile
       && !isa<ClangModuleUnit>(IGM.CurSourceFile)
-      && !IGM.getOptions().UseJIT) {
+      && !IGM.getOptions().IntegratedREPL) {
     CanSymbolicReference = [&](const DeclContext *dc) -> bool {
       // Symbolically reference types that are defined in the same file unit
       // as we're referencing from.

lib/Immediate/REPL.cpp

@@ -1004,6 +1004,7 @@ class REPLEnvironment {
     IRGenOpts.OptMode = OptimizationMode::NoOptimization;
     IRGenOpts.OutputKind = IRGenOutputKind::Module;
     IRGenOpts.UseJIT = true;
+    IRGenOpts.IntegratedREPL = true;
     IRGenOpts.DebugInfoKind = IRGenDebugInfoKind::None;
 
     if (!ParseStdlib) {