[flang-commits] [flang] [flang] Do not stop on mismatched DATA substring length (PR #69336)

[via flang-commits]

https://github.com/jeanPerier created https://github.com/llvm/llvm-project/pull/69336

https://reviews.llvm.org/D143819 turned mismatched DATA substring from a crash into a warning. However, the resulting DATA was incorrect when there were subsequent DATA values after the mismatch because the DATA to init conversion stopped. This change let the DATA to init continue.

I added a LengthMismatch tag instead of using SizeMismatch because the other situation where SizeMismatch is returned seem like bug situations to me (the DATA value is dropped and the offset is not advanced), so I did not want to continue DATA processing in these cases.

>From df4dca18015f286dadf47a52a4130f16ec2a5fce Mon Sep 17 00:00:00 2001
From: Jean Perier <jperier at nvidia.com>
Date: Tue, 17 Oct 2023 07:10:42 -0700
Subject: [PATCH] [flang] Do not stop on mismatched DATA substring length

https://reviews.llvm.org/D143819 turned mismatched DATA substring from
a crash into a warning. However, the resulting DATA was incorrect when
there were subsequent DATA values after the mismatch because the DATA
to init conversion stopped. This change let the DATA to init continue.

I added a LengthMismatch tag instead of using SizeMismatch because the
other situation where SizeMismatch is returned seem like bug situations
to me (the DATA value is dropped and the offset is not advanced), so I
did not want to continue DATA processing in these cases.
---
 flang/include/flang/Evaluate/initial-image.h |  4 ++--
 flang/lib/Semantics/data-to-inits.cpp        |  3 ++-
 flang/test/Semantics/data19.f90              | 13 +++++++++++++
 3 files changed, 17 insertions(+), 3 deletions(-)
 create mode 100644 flang/test/Semantics/data19.f90

diff --git a/flang/include/flang/Evaluate/initial-image.h b/flang/include/flang/Evaluate/initial-image.h
index 7c8f986f853a34b..e1f9a68acb00c20 100644
--- a/flang/include/flang/Evaluate/initial-image.h
+++ b/flang/include/flang/Evaluate/initial-image.h
@@ -22,7 +22,7 @@ namespace Fortran::evaluate {
 
 class InitialImage {
 public:
-  enum Result { Ok, NotAConstant, OutOfRange, SizeMismatch };
+  enum Result { Ok, NotAConstant, OutOfRange, SizeMismatch, LengthMismatch };
 
   explicit InitialImage(std::size_t bytes) : data_(bytes) {}
   InitialImage(InitialImage &&that) = default;
@@ -72,7 +72,7 @@ class InitialImage {
           auto scalar{x.At(at)}; // this is a std string; size() in chars
           auto scalarBytes{scalar.size() * KIND};
           if (scalarBytes != elementBytes) {
-            result = SizeMismatch;
+            result = LengthMismatch;
           }
           // Blank padding when short
           for (; scalarBytes < elementBytes; scalarBytes += KIND) {
diff --git a/flang/lib/Semantics/data-to-inits.cpp b/flang/lib/Semantics/data-to-inits.cpp
index 85bce874e78cdeb..188f3fa69617e7d 100644
--- a/flang/lib/Semantics/data-to-inits.cpp
+++ b/flang/lib/Semantics/data-to-inits.cpp
@@ -457,10 +457,11 @@ bool DataInitializationCompiler<DSV>::InitElement(
             folded.AsFortran(), DescribeElement());
       } else if (status == evaluate::InitialImage::OutOfRange) {
         OutOfRangeError();
-      } else if (status == evaluate::InitialImage::SizeMismatch) {
+      } else if (status == evaluate::InitialImage::LengthMismatch) {
         exprAnalyzer_.Say(
             "DATA statement value '%s' for '%s' has the wrong length"_warn_en_US,
             folded.AsFortran(), DescribeElement());
+        return true;
       } else {
         CHECK(exprAnalyzer_.context().AnyFatalError());
       }
diff --git a/flang/test/Semantics/data19.f90 b/flang/test/Semantics/data19.f90
new file mode 100644
index 000000000000000..6ed2e2144d401fc
--- /dev/null
+++ b/flang/test/Semantics/data19.f90
@@ -0,0 +1,13 @@
+! RUN: %flang_fc1 -fdebug-dump-symbols %s 2>&1 | FileCheck %s
+! Test truncation/padding in DATA statement.
+
+  character(len=3) :: c1, c2, c3(2), c4(2)
+  data c1(1:2), c1(3:3) /'123', '4'/
+  data c2(1:2), c2(3:3) /'1', '2'/
+  data c3(:)(1:2), c3(:)(3:3) /'123', '678', '4', '9'/
+  data c4(:)(1:2), c4(:)(3:3) /'1', '6', '2', '7'/
+end
+!CHECK:  c1 (InDataStmt) size=3 offset=0: ObjectEntity type: CHARACTER(3_4,1) init:"124"
+!CHECK:  c2 (InDataStmt) size=3 offset=3: ObjectEntity type: CHARACTER(3_4,1) init:"1 2"
+!CHECK:  c3 (InDataStmt) size=6 offset=6: ObjectEntity type: CHARACTER(3_4,1) shape: 1_8:2_8 init:[CHARACTER(KIND=1,LEN=3)::"124","679"]
+!CHECK:  c4 (InDataStmt) size=6 offset=12: ObjectEntity type: CHARACTER(3_4,1) shape: 1_8:2_8 init:[CHARACTER(KIND=1,LEN=3)::"1 2","6 7"]