[flang-commits] [PATCH] D145089: [flang] Warn about dangerous actual argument association with TARGET dummy arguments

[Peter Klausler via Phabricator via flang-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGfee3f0bd4acb: [flang] Warn about dangerous actual argument association with TARGET dummy… (authored by klausler).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D145089/new/

https://reviews.llvm.org/D145089

Files:
  flang/lib/Semantics/check-call.cpp
  flang/test/Semantics/call34.f90


Index: flang/test/Semantics/call34.f90
===================================================================
--- /dev/null
+++ flang/test/Semantics/call34.f90
@@ -0,0 +1,22 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1 -Werror
+module m
+ contains
+  subroutine foo(a)
+    real, intent(in), target :: a(:)
+  end subroutine
+end module
+
+program test
+  use m
+  real, target :: a(1)
+  real :: b(1)
+  call foo(a) ! ok
+  !WARNING: Any pointer associated with TARGET dummy argument 'a=' during this call must not be used afterwards, as 'b' is not a target
+  call foo(b)
+  !WARNING: Any pointer associated with TARGET dummy argument 'a=' during this call will not be associated with the value of '(a)' afterwards
+  call foo((a))
+  !WARNING: Any pointer associated with TARGET dummy argument 'a=' during this call will not be associated with the value of 'a([INTEGER(8)::1_8])' afterwards
+  call foo(a([1]))
+  !ERROR: Scalar actual argument may not be associated with assumed-shape dummy argument 'a='
+  call foo(a(1))
+end
Index: flang/lib/Semantics/check-call.cpp
===================================================================
--- flang/lib/Semantics/check-call.cpp
+++ flang/lib/Semantics/check-call.cpp
@@ -441,7 +441,8 @@
   // technically legal but worth emitting a warning
   // llvm-project issue #58973: constant actual argument passed in where dummy
   // argument is marked volatile
-  if (dummyIsVolatile && !IsVariable(actual)) {
+  bool actualIsVariable{evaluate::IsVariable(actual)};
+  if (dummyIsVolatile && !actualIsVariable) {
     messages.Say(
         "actual argument associated with VOLATILE %s is not a variable"_warn_en_US,
         dummyName);
@@ -599,6 +600,24 @@
         "Actual argument associated with %s may not be null pointer %s"_err_en_US,
         dummyName, actual.AsFortran());
   }
+
+  // Warn about dubious actual argument association with a TARGET dummy argument
+  if (dummy.attrs.test(characteristics::DummyDataObject::Attr::Target)) {
+    bool actualIsTemp{!actualIsVariable || HasVectorSubscript(actual) ||
+        evaluate::ExtractCoarrayRef(actual)};
+    if (actualIsTemp) {
+      messages.Say(
+          "Any pointer associated with TARGET %s during this call will not be associated with the value of '%s' afterwards"_warn_en_US,
+          dummyName, actual.AsFortran());
+    } else {
+      auto actualSymbolVector{GetSymbolVector(actual)};
+      if (!evaluate::GetLastTarget(actualSymbolVector)) {
+        messages.Say(
+            "Any pointer associated with TARGET %s during this call must not be used afterwards, as '%s' is not a target"_warn_en_US,
+            dummyName, actual.AsFortran());
+      }
+    }
+  }
 }
 
 static void CheckProcedureArg(evaluate::ActualArgument &arg,


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