From e632c5ec9604bcd125cb5ed00879b82a4fa03c51 Mon Sep 17 00:00:00 2001
From: Ellie Shin <ellie_shin@apple.com>
Date: Wed, 15 May 2024 15:35:40 -0700
Subject: [PATCH] -Add package-cmo check to bypassResilienceInPackage method.
 -Fix SILDeclRef getLinkageLimit() for GlobalAccessor to return Limit::None if
 bypassResilienceInPackage is enabled.

---
 lib/AST/Decl.cpp                 | 28 +++++++++++++++++++---------
 lib/SIL/IR/SILDeclRef.cpp        |  8 ++++++--
 lib/SIL/Verifier/SILVerifier.cpp | 30 ++++++++++++------------------
 3 files changed, 37 insertions(+), 29 deletions(-)

diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 46263924ce01c..64ac3f1e65ac4 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -3060,7 +3060,7 @@ bool AbstractStorageDecl::isResilient(ModuleDecl *M,
   case ResilienceExpansion::Maximal:
     if (M == getModuleContext())
       return false;
-    // Non-resilient if bypass optimization in package is enabled
+    // Access non-resiliently if package optimization is enabled
     if (bypassResilienceInPackage(M))
       return false;
     return isResilient();
@@ -4271,13 +4271,23 @@ bool ValueDecl::hasOpenAccess(const DeclContext *useDC) const {
 }
 
 bool ValueDecl::bypassResilienceInPackage(ModuleDecl *accessingModule) const {
-  // Client needs to opt in to bypass resilience checks at the use site.
-  // Client and the loaded module both need to be in the same package.
-  // The loaded module needs to be built from source and opt in to allow
-  // non-resilient access.
-  return getASTContext().LangOpts.EnableBypassResilienceInPackage &&
-         getModuleContext()->inSamePackage(accessingModule) &&
-         getModuleContext()->allowNonResilientAccess();
+  auto declModule = getModuleContext();
+  if (declModule->inSamePackage(accessingModule) &&
+      declModule->allowNonResilientAccess()) {
+    // If the defining module is built with package-cmo,
+    // allow direct access from the use site that belongs
+    // to accessingModule (client module).
+    if (declModule->isResilient() &&
+        declModule->serializePackageEnabled())
+      return true;
+
+    // If not, check if the client can still opt in to
+    // have a direct access to this decl from the use
+    // site with a flag.
+    // FIXME: serialize this flag to Module and get it via accessingModule.
+    return getASTContext().LangOpts.EnableBypassResilienceInPackage;
+  }
+  return false;
 }
 
 /// Given the formal access level for using \p VD, compute the scope where
@@ -5134,7 +5144,7 @@ bool NominalTypeDecl::isResilient(ModuleDecl *M,
     // non-resiliently in a maximal context.
     if (M == getModuleContext())
       return false;
-    // Non-resilient if bypass optimization in package is enabled
+    // Access non-resiliently if package optimization is enabled
     if (bypassResilienceInPackage(M))
       return false;
 
diff --git a/lib/SIL/IR/SILDeclRef.cpp b/lib/SIL/IR/SILDeclRef.cpp
index 346c21e44e6e3..e2cc7b35bb4b2 100644
--- a/lib/SIL/IR/SILDeclRef.cpp
+++ b/lib/SIL/IR/SILDeclRef.cpp
@@ -460,8 +460,12 @@ static LinkageLimit getLinkageLimit(SILDeclRef constant) {
   case Kind::EnumElement:
     return Limit::OnDemand;
 
-  case Kind::GlobalAccessor:
-    return cast<VarDecl>(d)->isResilient() ? Limit::NeverPublic : Limit::None;
+  case Kind::GlobalAccessor: {
+    auto varDecl = cast<VarDecl>(d);
+    return varDecl->isResilient() &&
+           !varDecl->getModuleContext()->allowNonResilientAccess() ?
+           Limit::NeverPublic : Limit::None;
+  }
 
   case Kind::DefaultArgGenerator:
     // If the default argument is to be serialized, only use non-ABI public
diff --git a/lib/SIL/Verifier/SILVerifier.cpp b/lib/SIL/Verifier/SILVerifier.cpp
index ba4ff6e1e3109..cff0aabacfffa 100644
--- a/lib/SIL/Verifier/SILVerifier.cpp
+++ b/lib/SIL/Verifier/SILVerifier.cpp
@@ -160,29 +160,23 @@ bool checkResilience(DeclType *D, ModuleDecl *accessingModule,
                      ResilienceExpansion expansion,
                      bool isSerializedForPackage) {
   auto declModule = D->getModuleContext();
-  // Explicitly bypassed for debugging with `bypass-resilience-checks`
+
+  // For DEBUGGING: this check looks up
+  // `bypass-resilience-checks`, which is
+  // an old flag used for debugging, and
+  // has nothing to do with optimizations.
   if (declModule->getBypassResilience())
     return false;
 
-  // Check whether the function or a decl referenced
-  // by the function was serialized with package-cmo
-  // optimization.
-  // If enabled, resilience expansion for the function
-  // is maximal (see SILFunction::getResilienceExpansion()).
+  // If the SIL function containing the decl D is
+  // [serialized_for_package], package-cmo had been
+  // enabled in its defining module, so direct access
+  // from a client module should be allowed.
   if (accessingModule != declModule &&
-      expansion == ResilienceExpansion::Maximal) {
-    // If the function is [serialized_for_package],
-    // package-cmo had been enabled in its defining
-    // module, so direct access should be allowed.
-    if (isSerializedForPackage)
-      return false;
-    // If not, check whether the referenced decl was
-    // serialized with package-cmo.
-    if (declModule->isResilient() &&
-        declModule->serializePackageEnabled() &&
-        declModule->inSamePackage(accessingModule))
+      expansion == ResilienceExpansion::Maximal &&
+      isSerializedForPackage)
       return false;
-  }
+
   return D->isResilient(accessingModule, expansion);
 }