[flang-commits] [flang] [llvm] [flang] Add functionality for calling `FLUSH` (PR #165942)
Miguel Saldivar via flang-commits
flang-commits at lists.llvm.org
Fri Oct 31 17:00:01 PDT 2025
https://github.com/Saldivarcher created https://github.com/llvm/llvm-project/pull/165942
Currently `FLUSH` was only available as a statement, so something like:
```fortran
program flush_stmt_example
implicit none
integer :: unit
! Open a file for writing
open(unit=10, file="flush_stmt.txt", status="replace", action="write")
write(10,*) "This line is written to the file."
flush(10) ! <-- flush statement, not a CALL
print *, "The file has been flushed. You can read it now before close."
close(10)
end program flush_stmt_example
```
If `FLUSH` was used as subroutine call, like `call flush(10)` there was no special handling of it. This PR should add that functionality.
Fixes #119418
>From d3e215fa40c2ef34a0a3bd0b25fd09cbecfdc49a Mon Sep 17 00:00:00 2001
From: Miguel Saldivar <saldivarcher at gmail.com>
Date: Fri, 31 Oct 2025 16:46:49 -0700
Subject: [PATCH] [flang] Add functionality for calling `FLUSH`
Currently `FLUSH` was only available as a statement, so something like:
```fortran
program flush_stmt_example
implicit none
integer :: unit
! Open a file for writing
open(unit=10, file="flush_stmt.txt", status="replace", action="write")
write(10,*) "This line is written to the file."
flush(10) ! <-- flush statement, not a CALL
print *, "The file has been flushed. You can read it now before close."
close(10)
end program flush_stmt_example
```
If `FLUSH` was used as subroutine call, like `call flush(10)` there was
no special handling of it. This PR should add that functionality.
Fixes #119418
---
flang-rt/lib/runtime/extensions.cpp | 11 +++++++++++
.../flang/Optimizer/Builder/IntrinsicCall.h | 1 +
.../Optimizer/Builder/Runtime/Intrinsics.h | 2 ++
flang/include/flang/Runtime/extensions.h | 1 +
flang/lib/Evaluate/intrinsics.cpp | 4 ++++
flang/lib/Optimizer/Builder/IntrinsicCall.cpp | 18 ++++++++++++++++++
.../Optimizer/Builder/Runtime/Intrinsics.cpp | 9 +++++++++
7 files changed, 46 insertions(+)
diff --git a/flang-rt/lib/runtime/extensions.cpp b/flang-rt/lib/runtime/extensions.cpp
index 19e75143705ab..d3a618c1a39ec 100644
--- a/flang-rt/lib/runtime/extensions.cpp
+++ b/flang-rt/lib/runtime/extensions.cpp
@@ -163,6 +163,17 @@ void FORTRAN_PROCEDURE_NAME(flush)(const int &unit) {
Cookie cookie{IONAME(BeginFlush)(unit, __FILE__, __LINE__)};
IONAME(EndIoStatement)(cookie);
}
+
+void RTNAME(Flush)(int unit) {
+ // We set the `unit == -1` on the `flush()` case, so flush all units.
+ if (unit < 0) {
+ Terminator terminator{__FILE__, __LINE__};
+ IoErrorHandler handler{terminator};
+ ExternalFileUnit::FlushAll(handler);
+ return;
+ }
+ FORTRAN_PROCEDURE_NAME(flush)(unit);
+}
} // namespace io
// CALL FDATE(DATE)
diff --git a/flang/include/flang/Optimizer/Builder/IntrinsicCall.h b/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
index 3407dd01dd504..51a3ae5af7688 100644
--- a/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
+++ b/flang/include/flang/Optimizer/Builder/IntrinsicCall.h
@@ -278,6 +278,7 @@ struct IntrinsicLibrary {
mlir::Value genExtremum(mlir::Type, llvm::ArrayRef<mlir::Value>);
void genFenceProxyAsync(llvm::ArrayRef<fir::ExtendedValue>);
mlir::Value genFloor(mlir::Type, llvm::ArrayRef<mlir::Value>);
+ void genFlush(llvm::ArrayRef<fir::ExtendedValue>);
mlir::Value genFraction(mlir::Type resultType,
mlir::ArrayRef<mlir::Value> args);
void genFree(mlir::ArrayRef<fir::ExtendedValue> args);
diff --git a/flang/include/flang/Optimizer/Builder/Runtime/Intrinsics.h b/flang/include/flang/Optimizer/Builder/Runtime/Intrinsics.h
index 7a97172cfbb9a..5121ccce921c6 100644
--- a/flang/include/flang/Optimizer/Builder/Runtime/Intrinsics.h
+++ b/flang/include/flang/Optimizer/Builder/Runtime/Intrinsics.h
@@ -51,6 +51,8 @@ mlir::Value genDsecnds(fir::FirOpBuilder &builder, mlir::Location loc,
void genEtime(fir::FirOpBuilder &builder, mlir::Location loc,
mlir::Value values, mlir::Value time);
+void genFlush(fir::FirOpBuilder &builder, mlir::Location loc, mlir::Value unit);
+
void genFree(fir::FirOpBuilder &builder, mlir::Location loc, mlir::Value ptr);
mlir::Value genFseek(fir::FirOpBuilder &builder, mlir::Location loc,
diff --git a/flang/include/flang/Runtime/extensions.h b/flang/include/flang/Runtime/extensions.h
index 9fd3e118a0f22..8db68eb9c245c 100644
--- a/flang/include/flang/Runtime/extensions.h
+++ b/flang/include/flang/Runtime/extensions.h
@@ -34,6 +34,7 @@ double RTNAME(Dsecnds)(double *refTime, const char *sourceFile, int line);
// CALL FLUSH(n) antedates the Fortran 2003 FLUSH statement.
void FORTRAN_PROCEDURE_NAME(flush)(const int &unit);
+void RTNAME(Flush)(int unit);
// GNU extension subroutine FDATE
void FORTRAN_PROCEDURE_NAME(fdate)(char *string, std::int64_t length);
diff --git a/flang/lib/Evaluate/intrinsics.cpp b/flang/lib/Evaluate/intrinsics.cpp
index 1de5e6b53ba71..d403afe9de307 100644
--- a/flang/lib/Evaluate/intrinsics.cpp
+++ b/flang/lib/Evaluate/intrinsics.cpp
@@ -1597,6 +1597,10 @@ static const IntrinsicInterface intrinsicSubroutine[]{
{"exit", {{"status", DefaultInt, Rank::scalar, Optionality::optional}}, {},
Rank::elemental, IntrinsicClass::impureSubroutine},
{"free", {{"ptr", Addressable}}, {}},
+ {"flush",
+ {{"unit", AnyInt, Rank::scalar, Optionality::optional,
+ common::Intent::In}},
+ {}, Rank::elemental, IntrinsicClass::impureSubroutine},
{"fseek",
{{"unit", AnyInt, Rank::scalar}, {"offset", AnyInt, Rank::scalar},
{"whence", AnyInt, Rank::scalar},
diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index 15ea84565dd75..317414ef0fec6 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -525,6 +525,10 @@ static constexpr IntrinsicHandler handlers[]{
{"back", asValue, handleDynamicOptional}}},
/*isElemental=*/false},
{"floor", &I::genFloor},
+ {"flush",
+ &I::genFlush,
+ {{{"unit", asValue, handleDynamicOptional}}},
+ /*isElemental=*/false},
{"fraction", &I::genFraction},
{"free", &I::genFree},
{"fseek",
@@ -4601,6 +4605,20 @@ mlir::Value IntrinsicLibrary::genFloor(mlir::Type resultType,
return builder.createConvert(loc, resultType, floor);
}
+// FLUSH
+void IntrinsicLibrary::genFlush(llvm::ArrayRef<fir::ExtendedValue> args) {
+ assert(args.size() == 1);
+
+ mlir::Value unit;
+ if (isStaticallyAbsent(args[0]))
+ // Give a sentinal value of `-1` on the `()` case.
+ unit = builder.createIntegerConstant(loc, builder.getI32Type(), -1);
+ else
+ unit = fir::getBase(args[0]);
+
+ fir::runtime::genFlush(builder, loc, unit);
+}
+
// FRACTION
mlir::Value IntrinsicLibrary::genFraction(mlir::Type resultType,
llvm::ArrayRef<mlir::Value> args) {
diff --git a/flang/lib/Optimizer/Builder/Runtime/Intrinsics.cpp b/flang/lib/Optimizer/Builder/Runtime/Intrinsics.cpp
index 110b1b20898c7..9fa3b18a255bd 100644
--- a/flang/lib/Optimizer/Builder/Runtime/Intrinsics.cpp
+++ b/flang/lib/Optimizer/Builder/Runtime/Intrinsics.cpp
@@ -137,6 +137,15 @@ void fir::runtime::genEtime(fir::FirOpBuilder &builder, mlir::Location loc,
fir::CallOp::create(builder, loc, runtimeFunc, args);
}
+void fir::runtime::genFlush(fir::FirOpBuilder &builder, mlir::Location loc,
+ mlir::Value unit) {
+ auto runtimeFunc = fir::runtime::getRuntimeFunc<mkRTKey(Flush)>(loc, builder);
+ llvm::SmallVector<mlir::Value> args = fir::runtime::createArguments(
+ builder, loc, runtimeFunc.getFunctionType(), unit);
+
+ fir::CallOp::create(builder, loc, runtimeFunc, args);
+}
+
void fir::runtime::genFree(fir::FirOpBuilder &builder, mlir::Location loc,
mlir::Value ptr) {
auto runtimeFunc = fir::runtime::getRuntimeFunc<mkRTKey(Free)>(loc, builder);
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