[flang-commits] [flang] 9469dc3 - [flang][runtime] Handle unconsumed repeated list-directed input items (#75400)

[via flang-commits]

Author: Peter Klausler
Date: 2023-12-26T15:44:31-08:00
New Revision: 9469dc38b01b857a6bef8a57480a30ddba61647d

URL: https://github.com/llvm/llvm-project/commit/9469dc38b01b857a6bef8a57480a30ddba61647d
DIFF: https://github.com/llvm/llvm-project/commit/9469dc38b01b857a6bef8a57480a30ddba61647d.diff

LOG: [flang][runtime] Handle unconsumed repeated list-directed input items (#75400)

If list-directed input contains a repeated item ("20*123.0") that is not
fully consumed by the READ statement's data item list, the end of that
READ statement was repositioning the input to the repeated value
("123.0"), leading to later confusion. Cancel the input item repetition
during EndIoStatement() processing to prevent this misbehavior.

Fixes llvm-test-suite/Fortran/gfortran/regression/list_read_4.f90.

Added: 
    

Modified: 
    flang/runtime/connection.cpp
    flang/runtime/connection.h
    flang/runtime/io-stmt.cpp
    flang/runtime/io-stmt.h

Removed: 
    


################################################################################
diff  --git a/flang/runtime/connection.cpp b/flang/runtime/connection.cpp
index 0abacd7995b471..91ac9a0e14e47b 100644
--- a/flang/runtime/connection.cpp
+++ b/flang/runtime/connection.cpp
@@ -46,13 +46,15 @@ SavedPosition::SavedPosition(IoStatementState &io) : io_{io} {
 }
 
 SavedPosition::~SavedPosition() {
-  ConnectionState &conn{io_.GetConnectionState()};
-  while (conn.currentRecordNumber > saved_.currentRecordNumber) {
-    io_.BackspaceRecord();
+  if (!cancelled_) {
+    ConnectionState &conn{io_.GetConnectionState()};
+    while (conn.currentRecordNumber > saved_.currentRecordNumber) {
+      io_.BackspaceRecord();
+    }
+    conn.leftTabLimit = saved_.leftTabLimit;
+    conn.furthestPositionInRecord = saved_.furthestPositionInRecord;
+    conn.positionInRecord = saved_.positionInRecord;
+    conn.pinnedFrame = saved_.pinnedFrame;
   }
-  conn.leftTabLimit = saved_.leftTabLimit;
-  conn.furthestPositionInRecord = saved_.furthestPositionInRecord;
-  conn.positionInRecord = saved_.positionInRecord;
-  conn.pinnedFrame = saved_.pinnedFrame;
 }
 } // namespace Fortran::runtime::io

diff  --git a/flang/runtime/connection.h b/flang/runtime/connection.h
index 70c20e17fd01ac..c9a7566f209881 100644
--- a/flang/runtime/connection.h
+++ b/flang/runtime/connection.h
@@ -111,10 +111,12 @@ class SavedPosition {
 public:
   explicit SavedPosition(IoStatementState &);
   ~SavedPosition();
+  void Cancel() { cancelled_ = true; }
 
 private:
   IoStatementState &io_;
   ConnectionState saved_;
+  bool cancelled_{false};
 };
 
 } // namespace Fortran::runtime::io

diff  --git a/flang/runtime/io-stmt.cpp b/flang/runtime/io-stmt.cpp
index 398f6127cf2758..921c6e625edb5d 100644
--- a/flang/runtime/io-stmt.cpp
+++ b/flang/runtime/io-stmt.cpp
@@ -189,6 +189,17 @@ InternalListIoStatementState<DIR>::InternalListIoStatementState(
     : InternalIoStatementState<DIR>{d, sourceFile, sourceLine},
       ioStatementState_{*this} {}
 
+template <Direction DIR>
+int InternalListIoStatementState<DIR>::EndIoStatement() {
+  if constexpr (DIR == Direction::Input) {
+    if (int status{ListDirectedStatementState<DIR>::EndIoStatement()};
+        status != IostatOk) {
+      return status;
+    }
+  }
+  return InternalIoStatementState<DIR>::EndIoStatement();
+}
+
 ExternalIoStatementBase::ExternalIoStatementBase(
     ExternalFileUnit &unit, const char *sourceFile, int sourceLine)
     : IoStatementBase{sourceFile, sourceLine}, unit_{unit} {}
@@ -707,6 +718,13 @@ ListDirectedStatementState<Direction::Output>::GetNextDataEdit(
   return edit;
 }
 
+int ListDirectedStatementState<Direction::Input>::EndIoStatement() {
+  if (repeatPosition_) {
+    repeatPosition_->Cancel();
+  }
+  return IostatOk;
+}
+
 std::optional<DataEdit>
 ListDirectedStatementState<Direction::Input>::GetNextDataEdit(
     IoStatementState &io, int maxRepeat) {
@@ -818,6 +836,17 @@ ListDirectedStatementState<Direction::Input>::GetNextDataEdit(
   return edit;
 }
 
+template <Direction DIR>
+int ExternalListIoStatementState<DIR>::EndIoStatement() {
+  if constexpr (DIR == Direction::Input) {
+    if (auto status{ListDirectedStatementState<DIR>::EndIoStatement()};
+        status != IostatOk) {
+      return status;
+    }
+  }
+  return ExternalIoStatementState<DIR>::EndIoStatement();
+}
+
 template <Direction DIR>
 bool ExternalUnformattedIoStatementState<DIR>::Receive(
     char *data, std::size_t bytes, std::size_t elementBytes) {
@@ -910,6 +939,16 @@ bool ChildUnformattedIoStatementState<DIR>::Receive(
   return this->child().parent().Receive(data, bytes, elementBytes);
 }
 
+template <Direction DIR> int ChildListIoStatementState<DIR>::EndIoStatement() {
+  if constexpr (DIR == Direction::Input) {
+    if (int status{ListDirectedStatementState<DIR>::EndIoStatement()};
+        status != IostatOk) {
+      return status;
+    }
+  }
+  return ChildIoStatementState<DIR>::EndIoStatement();
+}
+
 template class InternalIoStatementState<Direction::Output>;
 template class InternalIoStatementState<Direction::Input>;
 template class InternalFormattedIoStatementState<Direction::Output>;

diff  --git a/flang/runtime/io-stmt.h b/flang/runtime/io-stmt.h
index 91169f6c6e323e..0b6bcbd9af025a 100644
--- a/flang/runtime/io-stmt.h
+++ b/flang/runtime/io-stmt.h
@@ -304,6 +304,7 @@ class ListDirectedStatementState<Direction::Input>
     : public FormattedIoStatementState<Direction::Input> {
 public:
   bool inNamelistSequence() const { return inNamelistSequence_; }
+  int EndIoStatement();
 
   // Skips value separators, handles repetition and null values.
   // Vacant when '/' appears; present with descriptor == ListDirectedNullValue
@@ -317,6 +318,9 @@ class ListDirectedStatementState<Direction::Input>
   // NAMELIST input item.
   void ResetForNextNamelistItem(bool inNamelistSequence) {
     remaining_ = 0;
+    if (repeatPosition_) {
+      repeatPosition_->Cancel();
+    }
     eatComma_ = false;
     realPart_ = imaginaryPart_ = false;
     inNamelistSequence_ = inNamelistSequence;
@@ -399,6 +403,7 @@ class InternalListIoStatementState : public InternalIoStatementState<DIR>,
       const Descriptor &, const char *sourceFile = nullptr, int sourceLine = 0);
   IoStatementState &ioStatementState() { return ioStatementState_; }
   using ListDirectedStatementState<DIR>::GetNextDataEdit;
+  int EndIoStatement();
 
 private:
   IoStatementState ioStatementState_; // points to *this
@@ -474,6 +479,7 @@ class ExternalListIoStatementState : public ExternalIoStatementState<DIR>,
 public:
   using ExternalIoStatementState<DIR>::ExternalIoStatementState;
   using ListDirectedStatementState<DIR>::GetNextDataEdit;
+  int EndIoStatement();
 };
 
 template <Direction DIR>
@@ -532,6 +538,7 @@ class ChildListIoStatementState : public ChildIoStatementState<DIR>,
 public:
   using ChildIoStatementState<DIR>::ChildIoStatementState;
   using ListDirectedStatementState<DIR>::GetNextDataEdit;
+  int EndIoStatement();
 };
 
 template <Direction DIR>