[flang-commits] [PATCH] D100352: [flang] More precise enforcement of runtime constraint

[Peter Klausler via Phabricator via flang-commits]

klausler created this revision.
klausler added a reviewer: sscalpone.
klausler added a project: Flang.
Herald added a subscriber: jdoerfert.
klausler requested review of this revision.

An OPEN statement that affects an already connected unit
without changing its external file is required to have
STATUS="OLD" or default STATUS=.  The code was eliciting
spurious runtime errors in situations where an OPEN statement
pertained to an existing unit number but did not need to have
STATUS="OLD'.


https://reviews.llvm.org/D100352

Files:
  flang/runtime/io-stmt.cpp
  flang/runtime/unit.cpp
  flang/runtime/unit.h


Index: flang/runtime/unit.h
===================================================================
--- flang/runtime/unit.h
+++ flang/runtime/unit.h
@@ -50,11 +50,11 @@
   static void CloseAll(IoErrorHandler &);
   static void FlushAll(IoErrorHandler &);
 
-  void OpenUnit(OpenStatus, std::optional<Action>, Position,
+  void OpenUnit(std::optional<OpenStatus>, std::optional<Action>, Position,
       OwningPtr<char> &&path, std::size_t pathLength, Convert,
       IoErrorHandler &);
   void OpenAnonymousUnit(
-      OpenStatus, std::optional<Action>, Position, Convert, IoErrorHandler &);
+      std::optional<OpenStatus>, std::optional<Action>, Position, Convert, IoErrorHandler &);
   void CloseUnit(CloseStatus, IoErrorHandler &);
   void DestroyClosed();
 
Index: flang/runtime/unit.cpp
===================================================================
--- flang/runtime/unit.cpp
+++ flang/runtime/unit.cpp
@@ -89,7 +89,7 @@
   return GetUnitMap().NewUnit(terminator).unitNumber();
 }
 
-void ExternalFileUnit::OpenUnit(OpenStatus status, std::optional<Action> action,
+void ExternalFileUnit::OpenUnit(std::optional<OpenStatus> status, std::optional<Action> action,
     Position position, OwningPtr<char> &&newPath, std::size_t newPathLength,
     Convert convert, IoErrorHandler &handler) {
   if (executionEnvironment.conversion != Convert::Unknown) {
@@ -99,11 +99,13 @@
       (convert == Convert::LittleEndian && !isHostLittleEndian) ||
       (convert == Convert::BigEndian && isHostLittleEndian);
   if (IsOpen()) {
-    if (status == OpenStatus::Old &&
-        (!newPath.get() ||
-            (path() && pathLength() == newPathLength &&
-                std::memcmp(path(), newPath.get(), newPathLength) == 0))) {
-      // OPEN of existing unit, STATUS='OLD', not new FILE=
+    bool isSamePath{newPath.get() && path() && pathLength() == newPathLength && std::memcmp(path(), newPath.get(), newPathLength) == 0};
+    if (status && *status != OpenStatus::Old && isSamePath) {
+      handler.SignalError("OPEN statement for connected unit may not have explicit STATUS= other than 'OLD'");
+      return;
+    }
+    if (!newPath.get() || isSamePath) {
+      // OPEN of existing unit, STATUS='OLD' or unspecified, not new FILE=
       newPath.reset();
       return;
     }
@@ -113,7 +115,7 @@
     Close(CloseStatus::Keep, handler);
   }
   set_path(std::move(newPath), newPathLength);
-  Open(status, action, position, handler);
+  Open(status.value_or(OpenStatus::Unknown), action, position, handler);
   auto totalBytes{knownSize()};
   if (access == Access::Direct) {
     if (!isFixedRecordLength || !recordLength) {
@@ -146,7 +148,7 @@
   }
 }
 
-void ExternalFileUnit::OpenAnonymousUnit(OpenStatus status,
+void ExternalFileUnit::OpenAnonymousUnit(std::optional<OpenStatus> status,
     std::optional<Action> action, Position position, Convert convert,
     IoErrorHandler &handler) {
   // I/O to an unconnected unit reads/creates a local file, e.g. fort.7
Index: flang/runtime/io-stmt.cpp
===================================================================
--- flang/runtime/io-stmt.cpp
+++ flang/runtime/io-stmt.cpp
@@ -188,16 +188,12 @@
 }
 
 int OpenStatementState::EndIoStatement() {
-  if (wasExtant_ && status_ && *status_ != OpenStatus::Old) {
-    SignalError("OPEN statement for connected unit may not have STATUS= other "
-                "than 'OLD'");
-  }
   if (path_.get() || wasExtant_ ||
       (status_ && *status_ == OpenStatus::Scratch)) {
-    unit().OpenUnit(status_.value_or(OpenStatus::Unknown), action_, position_,
+    unit().OpenUnit(status_, action_, position_,
         std::move(path_), pathLength_, convert_, *this);
   } else {
-    unit().OpenAnonymousUnit(status_.value_or(OpenStatus::Unknown), action_,
+    unit().OpenAnonymousUnit(status_, action_,
         position_, convert_, *this);
   }
   if (access_) {


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