Modify clang declaration weakly-imported query to use Swift's code-gen target triple

Similarly to how #70564 configures 'ClangImporter's 'CodeGenerator' using Swift's compilation target triple, we must use the versioned version of the 'isWeakImported' query to determine linkage for imported Clang symbols.

Author: artemcm

include/swift/AST/ClangModuleLoader.h

@@ -140,6 +140,7 @@ class ClangModuleLoader : public ModuleLoader {
   /// (The implementing `ClangImporter` class maintains separate Target info
   /// for use by IRGen/CodeGen clients)
   virtual clang::TargetInfo &getModuleAvailabilityTarget() const = 0;
+  virtual clang::TargetInfo &getTargetInfo() const = 0;
 
   virtual clang::ASTContext &getClangASTContext() const = 0;
   virtual clang::Preprocessor &getClangPreprocessor() const = 0;

include/swift/ClangImporter/ClangImporter.h

@@ -570,7 +570,7 @@ class ClangImporter final : public ClangModuleLoader {
   /// instead. To distinguish IRGen clients from module loading clients,
   /// `getModuleAvailabilityTarget` should be used instead by module-loading
   /// clients.
-  clang::TargetInfo &getTargetInfo() const;
+  clang::TargetInfo &getTargetInfo() const override;
   clang::CodeGenOptions &getCodeGenOpts() const;
 
   std::string getClangModuleHash() const;

lib/AST/Decl.cpp

@@ -75,6 +75,7 @@
 
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/Module.h"
+#include "clang/Basic/TargetInfo.h"
 #include "clang/AST/Attr.h"
 #include "clang/AST/DeclObjC.h"
 
@@ -1468,9 +1469,9 @@ AvailabilityRange Decl::getAvailabilityForLinkage() const {
 
 bool Decl::isAlwaysWeakImported() const {
   // For a Clang declaration, trust Clang.
-  if (auto clangDecl = getClangDecl()) {
-    return clangDecl->isWeakImported();
-  }
+  if (auto clangDecl = getClangDecl())
+    return clangDecl->isWeakImported(
+        getASTContext().LangOpts.getMinPlatformVersion());
 
   if (getAttrs().hasAttribute<WeakLinkedAttr>())
     return true;

lib/SIL/IR/SILFunction.cpp

@@ -618,7 +618,8 @@ bool SILFunction::isWeakImported(ModuleDecl *module) const {
 
   // For imported functions check the Clang declaration.
   if (ClangNodeOwner)
-    return ClangNodeOwner->getClangDecl()->isWeakImported();
+    return ClangNodeOwner->getClangDecl()->isWeakImported(
+        getASTContext().LangOpts.getMinPlatformVersion());
 
   // For native functions check a flag on the SILFunction
   // itself.