[flang] Implement IERRNO intrinsic

Author: JDPailleux

flang/include/flang/Optimizer/Builder/IntrinsicCall.h

@@ -307,6 +307,8 @@ struct IntrinsicLibrary {
   mlir::Value genIeor(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue genIndex(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   mlir::Value genIor(mlir::Type, llvm::ArrayRef<mlir::Value>);
+  mlir::Value genIerrno(mlir::Type resultType,
+                        llvm::ArrayRef<mlir::Value> args);
   fir::ExtendedValue genIparity(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   fir::ExtendedValue genIsContiguous(mlir::Type,
                                      llvm::ArrayRef<fir::ExtendedValue>);

flang/include/flang/Optimizer/Builder/Runtime/Command.h

@@ -58,5 +58,9 @@ mlir::Value genGetEnvVariable(fir::FirOpBuilder &, mlir::Location,
 mlir::Value genGetCwd(fir::FirOpBuilder &builder, mlir::Location loc,
                       mlir::Value c);
 
+/// Generate a call to the Ierrno runtime function which implements
+/// the IERRNO intrinsic.
+mlir::Value genIerrno(fir::FirOpBuilder &, mlir::Location);
+
 } // namespace fir::runtime
 #endif // FORTRAN_OPTIMIZER_BUILDER_RUNTIME_COMMAND_H

flang/include/flang/Runtime/command.h

@@ -59,6 +59,10 @@ std::int32_t RTNAME(GetEnvVariable)(const Descriptor &name,
 // Calls getcwd()
 std::int32_t RTNAME(GetCwd)(
     const Descriptor &cwd, const char *sourceFile, int line);
+
+// IERRNO
+// Returns the last system error number, as given by the C errno variable.
+int RTNAME(Ierrno)();
 }
 } // namespace Fortran::runtime
 

flang/lib/Evaluate/intrinsics.cpp

@@ -591,6 +591,7 @@ static const IntrinsicInterface genericIntrinsicFunction[]{
         {{"i", OperandUnsigned}, {"j", OperandUnsigned, Rank::elementalOrBOZ}},
         OperandUnsigned},
     {"ieor", {{"i", BOZ}, {"j", SameIntOrUnsigned}}, SameIntOrUnsigned},
+    {"ierrno", {}, DefaultInt},
     {"image_index",
         {{"coarray", AnyData, Rank::coarray}, {"sub", AnyInt, Rank::vector}},
         DefaultInt, Rank::scalar, IntrinsicClass::transformationalFunction},

flang/lib/Optimizer/Builder/IntrinsicCall.cpp

@@ -403,6 +403,7 @@ static constexpr IntrinsicHandler handlers[]{
     {"ieee_unordered", &I::genIeeeUnordered},
     {"ieee_value", &I::genIeeeValue},
     {"ieor", &I::genIeor},
+    {"ierrno", &I::genIerrno},
     {"index",
      &I::genIndex,
      {{{"string", asAddr},
@@ -5546,6 +5547,13 @@ mlir::Value IntrinsicLibrary::genIeor(mlir::Type resultType,
                                                      args[1]);
 }
 
+// IERRNO
+mlir::Value IntrinsicLibrary::genIerrno(mlir::Type resultType,
+                                        llvm::ArrayRef<mlir::Value> args) {
+  assert(args.size() == 0);
+  return fir::runtime::genIerrno(builder, loc);
+}
+
 // INDEX
 fir::ExtendedValue
 IntrinsicLibrary::genIndex(mlir::Type resultType,

flang/lib/Optimizer/Builder/Runtime/Command.cpp

@@ -101,3 +101,11 @@ mlir::Value fir::runtime::genGetCwd(fir::FirOpBuilder &builder,
       builder, loc, runtimeFuncTy, cwd, sourceFile, sourceLine);
   return builder.create<fir::CallOp>(loc, func, args).getResult(0);
 }
+
+mlir::Value fir::runtime::genIerrno(fir::FirOpBuilder &builder,
+                                    mlir::Location loc) {
+  auto runtimeFunc =
+      fir::runtime::getRuntimeFunc<mkRTKey(Ierrno)>(loc, builder);
+  mlir::FunctionType runtimeFuncTy = runtimeFunc.getFunctionType();
+  return builder.create<fir::CallOp>(loc, runtimeFunc).getResult(0);
+}

flang/runtime/command.cpp

@@ -261,4 +261,6 @@ std::int32_t RTNAME(GetCwd)(
   return status;
 }
 
+int RTNAME(Ierrno)() { return errno; }
+
 } // namespace Fortran::runtime

flang/test/Lower/Intrinsics/ierrno.f90

@@ -0,0 +1,12 @@
+! RUN: bbc -emit-fir -hlfir=false %s -o - | FileCheck --check-prefixes=CHECK %s
+! RUN: %flang_fc1 -emit-fir -flang-deprecated-no-hlfir %s -o - | FileCheck --check-prefixes=CHECK %s
+
+! CHECK-LABEL: func @_QPtest_ierrno(
+subroutine test_ierrno(name)
+    integer :: i
+    i = ierrno()
+! CHECK: %[[VAL_0:.*]] = fir.alloca i32 {bindc_name = "i", uniq_name = "_QFtest_ierrnoEi"}
+! CHECK: %[[VAL_1:.*]] = fir.call @_FortranAIerrno
+! CHECK: fir.store %[[VAL_1]] to %[[VAL_0]] : !fir.ref<i32>
+! CHECK: return
+end subroutine test_ierrno