[flang][runtime] Preserve type when remapping monomorphic pointers (#149427)

Pointer remappings unconditionally update the element byte size and
derived type of the pointer's descriptor. This is okay when the pointer
is polymorphic, but not when a pointer is associated with an extended
type.

To communicate this monomorphic case to the runtime, add a new entry
point so as to not break forward binary compatibility.

2 files changed, 12 insertions, 9 deletions

diff --git a/flang/lib/Lower/Bridge.cpp b/flang/lib/Lower/Bridge.cpp
index 5f0783f..7ce397a 100644
--- a/flang/lib/Lower/Bridge.cpp
+++ b/flang/lib/Lower/Bridge.cpp
@@ -4703,8 +4703,10 @@ private:
       mlir::Value lhs = lhsMutableBox.getAddr();
       mlir::Value rhs = fir::getBase(genExprBox(loc, assign.rhs, stmtCtx));
       mlir::Value boundsDesc = createBoundArray(lbounds, ubounds, loc);
-      Fortran::lower::genPointerAssociateRemapping(*builder, loc, lhs, rhs,
-                                                   boundsDesc);
+      Fortran::lower::genPointerAssociateRemapping(
+          *builder, loc, lhs, rhs, boundsDesc,
+          lhsType && rhsType && !lhsType->IsPolymorphic() &&
+              rhsType->IsPolymorphic());
       return;
     }
     if (!lowerToHighLevelFIR() && explicitIterationSpace()) {
diff --git a/flang/lib/Lower/Runtime.cpp b/flang/lib/Lower/Runtime.cpp
index 5f73335..ae8bf0e 100644
--- a/flang/lib/Lower/Runtime.cpp
+++ b/flang/lib/Lower/Runtime.cpp
@@ -213,14 +213,15 @@ void Fortran::lower::genPointerAssociate(fir::FirOpBuilder &builder,
   builder.create<fir::CallOp>(loc, func, args);
 }
 
-void Fortran::lower::genPointerAssociateRemapping(fir::FirOpBuilder &builder,
-                                                  mlir::Location loc,
-                                                  mlir::Value pointer,
-                                                  mlir::Value target,
-                                                  mlir::Value bounds) {
+void Fortran::lower::genPointerAssociateRemapping(
+    fir::FirOpBuilder &builder, mlir::Location loc, mlir::Value pointer,
+    mlir::Value target, mlir::Value bounds, bool isMonomorphic) {
   mlir::func::FuncOp func =
-      fir::runtime::getRuntimeFunc<mkRTKey(PointerAssociateRemapping)>(loc,
-                                                                       builder);
+      isMonomorphic
+          ? fir::runtime::getRuntimeFunc<mkRTKey(
+                PointerAssociateRemappingMonomorphic)>(loc, builder)
+          : fir::runtime::getRuntimeFunc<mkRTKey(PointerAssociateRemapping)>(
+                loc, builder);
   auto fTy = func.getFunctionType();
   auto sourceFile = fir::factory::locationToFilename(builder, loc);
   auto sourceLine =