[PATCH] D83098: [flang] External I/O runtime work, repackaged (part 1)

[Peter Klausler via Phabricator via llvm-commits]

klausler created this revision.
klausler added reviewers: tskeith, sscalpone.
klausler added a project: Flang.
Herald added a reviewer: jdoerfert.
Herald added a reviewer: DavidTruby.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

Add a isFixedRecordLength flag member to Connection to
disambiguate the state of "record has known variable length"
from "record has fixed length".  Code that sets and tests this
flag will appear in later patches.  Rearrange data members to
reduce storage requirements, since Connection might indirectly
end up on a program stack frame.  Add a utility member function
BeginRecord(); use it in internal I/O processing.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D83098

Files:
  flang/runtime/connection.h
  flang/runtime/internal-unit.cpp


Index: flang/runtime/internal-unit.cpp
===================================================================
--- flang/runtime/internal-unit.cpp
+++ flang/runtime/internal-unit.cpp
@@ -17,6 +17,7 @@
 template <Direction DIR>
 InternalDescriptorUnit<DIR>::InternalDescriptorUnit(
     Scalar scalar, std::size_t length) {
+  isFixedRecordLength = true;
   recordLength = length;
   endfileRecordNumber = 2;
   void *pointer{reinterpret_cast<void *>(const_cast<char *>(scalar))};
@@ -33,6 +34,7 @@
       terminator, that.SizeInBytes() <= d.SizeInBytes(maxRank, true, 0));
   new (&d) Descriptor{that};
   d.Check();
+  isFixedRecordLength = true;
   recordLength = d.ElementBytes();
   endfileRecordNumber = d.Elements() + 1;
 }
@@ -123,8 +125,7 @@
     }
   }
   ++currentRecordNumber;
-  positionInRecord = 0;
-  furthestPositionInRecord = 0;
+  BeginRecord();
   return true;
 }
 
@@ -132,8 +133,7 @@
 void InternalDescriptorUnit<DIR>::BackspaceRecord(IoErrorHandler &handler) {
   RUNTIME_CHECK(handler, currentRecordNumber > 1);
   --currentRecordNumber;
-  positionInRecord = 0;
-  furthestPositionInRecord = 0;
+  BeginRecord();
 }
 
 template class InternalDescriptorUnit<Direction::Output>;
Index: flang/runtime/connection.h
===================================================================
--- flang/runtime/connection.h
+++ flang/runtime/connection.h
@@ -26,9 +26,10 @@
 // established in an OPEN statement.
 struct ConnectionAttributes {
   Access access{Access::Sequential}; // ACCESS='SEQUENTIAL', 'DIRECT', 'STREAM'
-  std::optional<std::int64_t> recordLength; // RECL= when fixed-length
   bool isUnformatted{false}; // FORM='UNFORMATTED'
   bool isUTF8{false}; // ENCODING='UTF-8'
+  bool isFixedRecordLength{false}; // RECL= on OPEN
+  std::optional<std::int64_t> recordLength; // RECL= or current record
 };
 
 struct ConnectionState : public ConnectionAttributes {
@@ -37,6 +38,12 @@
   void HandleAbsolutePosition(std::int64_t);
   void HandleRelativePosition(std::int64_t);
 
+  void BeginRecord() {
+    positionInRecord = 0;
+    furthestPositionInRecord = 0;
+    leftTabLimit.reset();
+  }
+
   // Positions in a record file (sequential or direct, not stream)
   std::int64_t currentRecordNumber{1}; // 1 is first
   std::int64_t positionInRecord{0}; // offset in current record


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