[flang][fir] Upstream utility function valueHasFirAttribute()

This function will be used in subsequent upstreaming merges.

Author: Jean Perier

Differential Revision: https://reviews.llvm.org/D97502

flang/include/flang/Optimizer/Dialect/FIROpsSupport.h

@@ -6,8 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef OPTIMIZER_DIALECT_FIROPSSUPPORT_H
-#define OPTIMIZER_DIALECT_FIROPSSUPPORT_H
+#ifndef FORTRAN_OPTIMIZER_DIALECT_FIROPSSUPPORT_H
+#define FORTRAN_OPTIMIZER_DIALECT_FIROPSSUPPORT_H
 
 #include "flang/Optimizer/Dialect/FIROps.h"
 #include "mlir/Dialect/StandardOps/IR/Ops.h"
@@ -59,6 +59,21 @@ fir::GlobalOp createGlobalOp(mlir::Location loc, mlir::ModuleOp module,
                              llvm::StringRef name, mlir::Type type,
                              llvm::ArrayRef<mlir::NamedAttribute> attrs = {});
 
+/// Attribute to mark Fortran entities with the CONTIGUOUS attribute.
+constexpr llvm::StringRef getContiguousAttrName() { return "fir.contiguous"; }
+/// Attribute to mark Fortran entities with the OPTIONAL attribute.
+constexpr llvm::StringRef getOptionalAttrName() { return "fir.optional"; }
+
+/// Tell if \p value is:
+///   - a function argument that has attribute \p attributeName
+///   - or, the result of fir.alloca/fir.allocamem op that has attribute \p
+///     attributeName
+///   - or, the result of a fir.address_of of a fir.global that has attribute \p
+///     attributeName
+///   - or, a fir.box loaded from a fir.ref<fir.box> that matches one of the
+///     previous cases.
+bool valueHasFirAttribute(mlir::Value value, llvm::StringRef attributeName);
+
 } // namespace fir
 
-#endif // OPTIMIZER_DIALECT_FIROPSSUPPORT_H
+#endif // FORTRAN_OPTIMIZER_DIALECT_FIROPSSUPPORT_H

flang/lib/Optimizer/Dialect/FIROps.cpp

@@ -1966,6 +1966,47 @@ fir::GlobalOp fir::createGlobalOp(mlir::Location loc, mlir::ModuleOp module,
   return result;
 }
 
+bool fir::valueHasFirAttribute(mlir::Value value,
+                               llvm::StringRef attributeName) {
+  // If this is a fir.box that was loaded, the fir attributes will be on the
+  // related fir.ref<fir.box> creation.
+  if (value.getType().isa<fir::BoxType>())
+    if (auto definingOp = value.getDefiningOp())
+      if (auto loadOp = mlir::dyn_cast<fir::LoadOp>(definingOp))
+        value = loadOp.memref();
+  // If this is a function argument, look in the argument attributes.
+  if (auto blockArg = value.dyn_cast<mlir::BlockArgument>()) {
+    if (blockArg.getOwner() && blockArg.getOwner()->isEntryBlock())
+      if (auto funcOp =
+              mlir::dyn_cast<mlir::FuncOp>(blockArg.getOwner()->getParentOp()))
+        if (funcOp.getArgAttr(blockArg.getArgNumber(), attributeName))
+          return true;
+    return false;
+  }
+
+  if (auto definingOp = value.getDefiningOp()) {
+    // If this is an allocated value, look at the allocation attributes.
+    if (mlir::isa<fir::AllocMemOp>(definingOp) ||
+        mlir::isa<AllocaOp>(definingOp))
+      return definingOp->hasAttr(attributeName);
+    // If this is an imported global, look at AddrOfOp and GlobalOp attributes.
+    // Both operations are looked at because use/host associated variable (the
+    // AddrOfOp) can have ASYNCHRONOUS/VOLATILE attributes even if the ultimate
+    // entity (the globalOp) does not have them.
+    if (auto addressOfOp = mlir::dyn_cast<fir::AddrOfOp>(definingOp)) {
+      if (addressOfOp->hasAttr(attributeName))
+        return true;
+      if (auto module = definingOp->getParentOfType<mlir::ModuleOp>())
+        if (auto globalOp =
+                module.lookupSymbol<fir::GlobalOp>(addressOfOp.symbol()))
+          return globalOp->hasAttr(attributeName);
+    }
+  }
+  // TODO: Construct associated entities attributes. Decide where the fir
+  // attributes must be placed/looked for in this case.
+  return false;
+}
+
 // Tablegen operators
 
 #define GET_OP_CLASSES