[flang-commits] [flang] [flang] Improve OpenACC SELF clause parser (PR #135883)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-flang-parser

@llvm/pr-subscribers-flang-semantics

Author: Peter Klausler (klausler)

<details>
<summary>Changes</summary>

The current parser can fail on "self(x * 2)" by recognizing just "x" as a one-element list of object names and then failing at a higher level because it never reached the right parenthesis. Add lookahead checks and error recovery.

Fixes https://github.com/llvm/llvm-project/issues/135810.

---
Full diff: https://github.com/llvm/llvm-project/pull/135883.diff


3 Files Affected:

- (modified) flang/lib/Parser/openacc-parsers.cpp (+7-2) 
- (added) flang/test/Semantics/OpenACC/bug135810-1.f90 (+9) 
- (added) flang/test/Semantics/OpenACC/bug135810-2.f90 (+12) 


``````````diff
diff --git a/flang/lib/Parser/openacc-parsers.cpp b/flang/lib/Parser/openacc-parsers.cpp
index fb731ee52cbba..5e0a56b1d374c 100644
--- a/flang/lib/Parser/openacc-parsers.cpp
+++ b/flang/lib/Parser/openacc-parsers.cpp
@@ -126,8 +126,13 @@ TYPE_PARSER(construct<AccDefaultClause>(
 // SELF clause is either a simple optional condition for compute construct
 // or a synonym of the HOST clause for the update directive 2.14.4 holding
 // an object list.
-TYPE_PARSER(construct<AccSelfClause>(Parser<AccObjectList>{}) ||
-    construct<AccSelfClause>(scalarLogicalExpr))
+TYPE_PARSER(
+    construct<AccSelfClause>(Parser<AccObjectList>{}) / lookAhead(")"_tok) ||
+    construct<AccSelfClause>(scalarLogicalExpr / lookAhead(")"_tok)) ||
+    construct<AccSelfClause>(
+        recovery(fail<std::optional<ScalarLogicalExpr>>(
+                     "logical expression or object list expected"_err_en_US),
+            SkipTo<')'>{} >> pure<std::optional<ScalarLogicalExpr>>())))
 
 // Modifier for copyin, copyout, cache and create
 TYPE_PARSER(construct<AccDataModifier>(
diff --git a/flang/test/Semantics/OpenACC/bug135810-1.f90 b/flang/test/Semantics/OpenACC/bug135810-1.f90
new file mode 100644
index 0000000000000..c40f4720b4f06
--- /dev/null
+++ b/flang/test/Semantics/OpenACC/bug135810-1.f90
@@ -0,0 +1,9 @@
+! RUN: %python %S/../test_errors.py %s %flang -fopenacc
+integer function square(x)
+    implicit none
+    integer, intent(in) :: x
+!ERROR: Must have LOGICAL type, but is INTEGER(4)
+    !$acc parallel self(x * 2)
+    !$acc end parallel
+    square = x * x
+end function square
diff --git a/flang/test/Semantics/OpenACC/bug135810-2.f90 b/flang/test/Semantics/OpenACC/bug135810-2.f90
new file mode 100644
index 0000000000000..8ed608b0b4cc9
--- /dev/null
+++ b/flang/test/Semantics/OpenACC/bug135810-2.f90
@@ -0,0 +1,12 @@
+! RUN: %python %S/../test_errors.py %s %flang -fopenacc
+integer function square(x)
+    implicit none
+    integer, intent(in) :: x
+!ERROR: logical expression or object list expected
+    !$acc parallel self(,)
+    !$acc end parallel
+!ERROR: logical expression or object list expected
+    !$acc parallel self(.true., )
+    !$acc end parallel
+    square = x * x
+end function square

``````````

</details>


https://github.com/llvm/llvm-project/pull/135883