[flang-commits] [flang] 174cabe - [flang] Fix cycle-catcher in procedure characterization

[Peter Klausler via flang-commits]

Author: Peter Klausler
Date: 2022-03-25T09:49:55-07:00
New Revision: 174cabeda57d8d53601d2970b426bf9ee865f2f4

URL: https://github.com/llvm/llvm-project/commit/174cabeda57d8d53601d2970b426bf9ee865f2f4
DIFF: https://github.com/llvm/llvm-project/commit/174cabeda57d8d53601d2970b426bf9ee865f2f4.diff

LOG: [flang] Fix cycle-catcher in procedure characterization

The "seenProcs" sets passed as arguments to the procedure and dummy
procedure characterization routines need to be passed by value so that
local updates to those sets do not become permanent.  They are
presently passed by reference and that has led to bogus errors about
recursively defined procedures in testing.

(It might be faster to pass the sets by reference and undo those local
updates in these functions, but that's error-prone, and the performance
difference is not expected to be detectable in practice.)

Differential Revision: https://reviews.llvm.org/D122439

Added: 
    

Modified: 
    flang/lib/Evaluate/characteristics.cpp

Removed: 
    


################################################################################
diff  --git a/flang/lib/Evaluate/characteristics.cpp b/flang/lib/Evaluate/characteristics.cpp
index b0a130d278530..e79c563c136f2 100644
--- a/flang/lib/Evaluate/characteristics.cpp
+++ b/flang/lib/Evaluate/characteristics.cpp
@@ -366,11 +366,11 @@ static std::string GetSeenProcs(
 // 15.4.3.6, paragraph 2.
 static std::optional<DummyArgument> CharacterizeDummyArgument(
     const semantics::Symbol &symbol, FoldingContext &context,
-    semantics::UnorderedSymbolSet &seenProcs);
+    semantics::UnorderedSymbolSet seenProcs);
 
 static std::optional<Procedure> CharacterizeProcedure(
     const semantics::Symbol &original, FoldingContext &context,
-    semantics::UnorderedSymbolSet &seenProcs) {
+    semantics::UnorderedSymbolSet seenProcs) {
   Procedure result;
   const auto &symbol{ResolveAssociations(original)};
   if (seenProcs.find(symbol) != seenProcs.end()) {
@@ -508,7 +508,7 @@ static std::optional<Procedure> CharacterizeProcedure(
 
 static std::optional<DummyProcedure> CharacterizeDummyProcedure(
     const semantics::Symbol &symbol, FoldingContext &context,
-    semantics::UnorderedSymbolSet &seenProcs) {
+    semantics::UnorderedSymbolSet seenProcs) {
   if (auto procedure{CharacterizeProcedure(symbol, context, seenProcs)}) {
     // Dummy procedures may not be elemental.  Elemental dummy procedure
     // interfaces are errors when the interface is not intrinsic, and that
@@ -562,7 +562,7 @@ bool DummyArgument::IsCompatibleWith(const DummyArgument &actual) const {
 
 static std::optional<DummyArgument> CharacterizeDummyArgument(
     const semantics::Symbol &symbol, FoldingContext &context,
-    semantics::UnorderedSymbolSet &seenProcs) {
+    semantics::UnorderedSymbolSet seenProcs) {
   auto name{symbol.name().ToString()};
   if (symbol.has<semantics::ObjectEntityDetails>() ||
       symbol.has<semantics::EntityDetails>()) {