[flang-commits] [flang] [Flang][OpenMP] Don't expect block arguments using early privatization (PR #105842)

[Sergio Afonso via flang-commits]

https://github.com/skatrak created https://github.com/llvm/llvm-project/pull/105842

There are some spots where all symbols to privatize collected by a `DataSharingProcessor` instance are expected to have corresponding entry block arguments associated regardless of whether delayed privatization was enabled.

This can result in compiler crashes if a `DataSharingProcessor` instance created with `useDelayedPrivatization=false` is queried in this way. The solution proposed by this patch is to provide another public method to query specifically delayed privatization symbols, which will either be empty or point to the complete set of symbols to privatize accordingly.

>From 039edceba6bf2ee6e815abf8a4f10cc0e973da61 Mon Sep 17 00:00:00 2001
From: Sergio Afonso <safonsof at amd.com>
Date: Fri, 23 Aug 2024 16:04:37 +0100
Subject: [PATCH] [Flang][OpenMP] Don't expect block arguments using early
 privatization

There are some spots where all symbols to privatize collected by a
`DataSharingProcessor` instance are expected to have corresponding entry
block arguments associated regardless of whether delayed privatization was
enabled.

This can result in compiler crashes if a `DataSharingProcessor` instance
created with `useDelayedPrivatization=false` is queried in this way. The
solution proposed by this patch is to provide another public method to query
specifically delayed privatization symbols, which will either be empty or point
to the complete set of symbols to privatize accordingly.
---
 flang/lib/Lower/OpenMP/DataSharingProcessor.h | 6 ++++++
 flang/lib/Lower/OpenMP/OpenMP.cpp             | 6 +++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/flang/lib/Lower/OpenMP/DataSharingProcessor.h b/flang/lib/Lower/OpenMP/DataSharingProcessor.h
index 1e9d07ec13857d..166cdfa37fc7fa 100644
--- a/flang/lib/Lower/OpenMP/DataSharingProcessor.h
+++ b/flang/lib/Lower/OpenMP/DataSharingProcessor.h
@@ -153,6 +153,12 @@ class DataSharingProcessor {
   getAllSymbolsToPrivatize() const {
     return allPrivatizedSymbols;
   }
+
+  llvm::ArrayRef<const semantics::Symbol *> getDelayedPrivSymbols() const {
+    return useDelayedPrivatization
+               ? allPrivatizedSymbols.getArrayRef()
+               : llvm::ArrayRef<const semantics::Symbol *>();
+  }
 };
 
 } // namespace omp
diff --git a/flang/lib/Lower/OpenMP/OpenMP.cpp b/flang/lib/Lower/OpenMP/OpenMP.cpp
index d614db8b68ef65..e445731883f06f 100644
--- a/flang/lib/Lower/OpenMP/OpenMP.cpp
+++ b/flang/lib/Lower/OpenMP/OpenMP.cpp
@@ -882,7 +882,7 @@ static void genBodyOfTargetOp(
   }
 
   for (auto [argIndex, argSymbol] :
-       llvm::enumerate(dsp.getAllSymbolsToPrivatize())) {
+       llvm::enumerate(dsp.getDelayedPrivSymbols())) {
     argIndex = mapSyms.size() + argIndex;
 
     const mlir::BlockArgument &arg = region.getArgument(argIndex);
@@ -1494,8 +1494,8 @@ genParallelOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
                              allRegionArgLocs);
 
     llvm::SmallVector<const semantics::Symbol *> allSymbols(reductionSyms);
-    allSymbols.append(dsp.getAllSymbolsToPrivatize().begin(),
-                      dsp.getAllSymbolsToPrivatize().end());
+    allSymbols.append(dsp.getDelayedPrivSymbols().begin(),
+                      dsp.getDelayedPrivSymbols().end());
 
     unsigned argIdx = 0;
     for (const semantics::Symbol *arg : allSymbols) {