[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.
llvm · Dec 26, 2023 · 9469dc3 · 9469dc3
1 parent 7b50176
commit 9469dc3
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Showing 4 changed files with 57 additions and 7 deletions.
diff --git 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
@@ -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
@@ -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
@@ -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>