[flang] Handle substring in data statement constant

[klausler]

The case of a constant substring wasn't handled in the parser for data statement constants.

Fixes #119005.

[llvmbot]

@llvm/pr-subscribers-flang-parser

Author: Peter Klausler (klausler)

Changes

The case of a constant substring wasn't handled in the parser for data statement constants.

Fixes #119005.

---

Full diff: https://github.com/llvm/llvm-project/pull/120130.diff

5 Files Affected:

• (modified) flang/include/flang/Parser/parse-tree.h (+4-3)
• (modified) flang/lib/Parser/Fortran-parsers.cpp (+3-1)
• (modified) flang/lib/Parser/expr-parsers.cpp (+1-1)
• (modified) flang/lib/Parser/type-parsers.h (+1)
• (added) flang/test/Parser/lit-substr-data.f90 (+7)

diff --git a/flang/include/flang/Parser/parse-tree.h b/flang/include/flang/Parser/parse-tree.h
index 1d97126d17dbc4..f87a1cfceb37ba 100644
--- a/flang/include/flang/Parser/parse-tree.h
+++ b/flang/include/flang/Parser/parse-tree.h
@@ -1481,9 +1481,10 @@ struct DataStmtConstant {
   UNION_CLASS_BOILERPLATE(DataStmtConstant);
   CharBlock source;
   mutable TypedExpr typedExpr;
-  std::variant<LiteralConstant, SignedIntLiteralConstant,
-      SignedRealLiteralConstant, SignedComplexLiteralConstant, NullInit,
-      common::Indirection<Designator>, StructureConstructor>
+  std::variant<common::Indirection<CharLiteralConstantSubstring>,
+      LiteralConstant, SignedIntLiteralConstant, SignedRealLiteralConstant,
+      SignedComplexLiteralConstant, NullInit, common::Indirection<Designator>,
+      StructureConstructor>
       u;
 };
 
diff --git a/flang/lib/Parser/Fortran-parsers.cpp b/flang/lib/Parser/Fortran-parsers.cpp
index a3d2c363108073..426d1d01793612 100644
--- a/flang/lib/Parser/Fortran-parsers.cpp
+++ b/flang/lib/Parser/Fortran-parsers.cpp
@@ -930,7 +930,9 @@ TYPE_PARSER(construct<DataStmtRepeat>(intLiteralConstant) ||
 // So we parse literal constants, designator, null-init, and
 // structure-constructor, so that semantics can figure things out later
 // with the symbol table.
-TYPE_PARSER(sourced(first(construct<DataStmtConstant>(literalConstant),
+TYPE_PARSER(sourced(first(
+    construct<DataStmtConstant>(indirect(charLiteralConstantSubstring)),
+    construct<DataStmtConstant>(literalConstant),
     construct<DataStmtConstant>(signedRealLiteralConstant),
     construct<DataStmtConstant>(signedIntLiteralConstant),
     extension<LanguageFeature::SignedComplexLiteral>(
diff --git a/flang/lib/Parser/expr-parsers.cpp b/flang/lib/Parser/expr-parsers.cpp
index 77a13de7fd02d8..0b6e21e1ba2ff2 100644
--- a/flang/lib/Parser/expr-parsers.cpp
+++ b/flang/lib/Parser/expr-parsers.cpp
@@ -68,7 +68,7 @@ TYPE_PARSER(construct<AcImpliedDoControl>(
 // type-param-inquiry is parsed as a structure component, except for
 // substring%KIND/LEN
 constexpr auto primary{instrumented("primary"_en_US,
-    first(construct<Expr>(indirect(Parser<CharLiteralConstantSubstring>{})),
+    first(construct<Expr>(indirect(charLiteralConstantSubstring)),
         construct<Expr>(literalConstant),
         construct<Expr>(construct<Expr::Parentheses>("(" >>
             expr / !","_tok / recovery(")"_tok, SkipPastNested<'(', ')'>{}))),
diff --git a/flang/lib/Parser/type-parsers.h b/flang/lib/Parser/type-parsers.h
index d7e0cd06c3f444..623437f9d2e1d8 100644
--- a/flang/lib/Parser/type-parsers.h
+++ b/flang/lib/Parser/type-parsers.h
@@ -63,6 +63,7 @@ constexpr Parser<KindParam> kindParam; // R709
 constexpr Parser<RealLiteralConstant> realLiteralConstant; // R714
 constexpr Parser<CharLength> charLength; // R723
 constexpr Parser<CharLiteralConstant> charLiteralConstant; // R724
+constexpr Parser<CharLiteralConstantSubstring> charLiteralConstantSubstring;
 constexpr Parser<Initialization> initialization; // R743 & R805
 constexpr Parser<DerivedTypeSpec> derivedTypeSpec; // R754
 constexpr Parser<TypeDeclarationStmt> typeDeclarationStmt; // R801
diff --git a/flang/test/Parser/lit-substr-data.f90 b/flang/test/Parser/lit-substr-data.f90
new file mode 100644
index 00000000000000..7eed616a1ee2ec
--- /dev/null
+++ b/flang/test/Parser/lit-substr-data.f90
@@ -0,0 +1,7 @@
+!RUN: %flang_fc1 -fdebug-unparse %s 2>&1 | FileCheck %s
+!Regression test for bug #119005
+character*2 :: ary4
+!CHECK: DATA ary4/"cd"/
+data ary4/"abcdef"(3:4)/
+end
+

[eugeneepshteyn]

Perhaps the comment above (starting on line 921) could be updated to include literal constant substrings?

[psteinfeld]

All builds and tests correctly and looks good.

[eugeneepshteyn]

Question: indirect here is just to ensure that charLiteralConstantSubstring is not null?

[klausler]

No, it allows the type CharLiteralConstantSubstring to be forward-referenced before it can be defined.

[eugeneepshteyn]

One comment change request, but otherwise LGTM