Re: [OG12][PATCH] OpenMP: Fix ICE with OMP metadirectives

[Paul-Antoine Arras <pa@codesourcery.com>]

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Hi Tobias,

Thanks for your review.

Here is a revised patch resulting from your comments.

The only issue that I could not easily fix is the following code 
triggering an ICE:

```
    !$OMP begin metadirective &
    !$OMP   when ( user = { condition ( UseDevice ) } &
    !$OMP     : nothing ) &
    !$OMP   default ( parallel )
    block
       call foo()
    end block
    call bar()	<--- ICE
    !$omp end metadirective
```

I filed a PR on Bugzilla: 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107067

Is it OK for you?
-- 
PA

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From 03476214bda71c6581b7978cf9fd5b701896a052 Mon Sep 17 00:00:00 2001
From: Paul-Antoine Arras <pa@codesourcery.com>
Date: Wed, 21 Sep 2022 15:52:56 +0000
Subject: [PATCH] OpenMP: Fix ICE with OMP metadirectives

Problem: ending an OpenMP metadirective block with an OMP end statement
results in an internal compiler error.
Solution: reject invalid end statements and issue a proper diagnostic.

This revision also fixes a couple of minor metadirective issues and adds
related test cases.

gcc/fortran/ChangeLog:

	* parse.cc (gfc_ascii_statement): Missing $ in !$OMP END METADIRECTIVE.
	(parse_omp_structured_block): Fix handling of OMP end metadirective.
	(parse_omp_metadirective_body): Reject OMP end statements
	at the end of an OMP metadirective.

gcc/testsuite/ChangeLog:

	* gfortran.dg/gomp/metadirective-1.f90: Match !$OMP END METADIRECTIVE.
	* gfortran.dg/gomp/metadirective-10.f90: New test.
	* gfortran.dg/gomp/metadirective-11.f90: New xfail test.
	* gfortran.dg/gomp/metadirective-9.f90: New test.
---
 gcc/fortran/ChangeLog.omp                     |  7 ++++
 gcc/fortran/parse.cc                          | 32 ++++++++++-----
 gcc/testsuite/ChangeLog.omp                   |  7 ++++
 .../gfortran.dg/gomp/metadirective-1.f90      |  2 +-
 .../gfortran.dg/gomp/metadirective-10.f90     | 40 +++++++++++++++++++
 .../gfortran.dg/gomp/metadirective-11.f90     | 33 +++++++++++++++
 .../gfortran.dg/gomp/metadirective-9.f90      | 30 ++++++++++++++
 7 files changed, 141 insertions(+), 10 deletions(-)
 create mode 100644 gcc/testsuite/gfortran.dg/gomp/metadirective-10.f90
 create mode 100644 gcc/testsuite/gfortran.dg/gomp/metadirective-11.f90
 create mode 100644 gcc/testsuite/gfortran.dg/gomp/metadirective-9.f90

diff --git gcc/fortran/ChangeLog.omp gcc/fortran/ChangeLog.omp
index 8c89cd5bd43..14f897e8fec 100644
--- gcc/fortran/ChangeLog.omp
+++ gcc/fortran/ChangeLog.omp
@@ -1,3 +1,10 @@
+2022-09-21  Paul-Antoine Arras  <pa@codesourcery.com>
+
+	* parse.cc (gfc_ascii_statement): Missing $ in !$OMP END METADIRECTIVE.
+	(parse_omp_structured_block): Fix handling of OMP end metadirective.
+	(parse_omp_metadirective_body): Reject OMP end statements
+	at the end of an OMP metadirective.
+
 2022-09-09  Tobias Burnus  <tobias@codesourcery.com>
 
 	Backport from mainline:
diff --git gcc/fortran/parse.cc gcc/fortran/parse.cc
index b35d76a4f6b..fc88111a7ad 100644
--- gcc/fortran/parse.cc
+++ gcc/fortran/parse.cc
@@ -2517,7 +2517,7 @@ gfc_ascii_statement (gfc_statement st)
       p = "!$OMP END MASTER TASKLOOP SIMD";
       break;
     case ST_OMP_END_METADIRECTIVE:
-      p = "!OMP END METADIRECTIVE";
+      p = "!$OMP END METADIRECTIVE";
       break;
     case ST_OMP_END_ORDERED:
       p = "!$OMP END ORDERED";
@@ -5643,9 +5643,15 @@ parse_omp_structured_block (gfc_statement omp_st, bool workshare_stmts_only)
   np->block = NULL;
 
   omp_end_st = gfc_omp_end_stmt (omp_st, false, true);
-  if (omp_st == ST_NONE)
+  if (omp_end_st == ST_NONE)
     gcc_unreachable ();
 
+  /* If handling a metadirective variant, treat 'omp end metadirective'
+     as the expected end statement for the current construct.  */
+  if (gfc_state_stack->previous != NULL
+      && gfc_state_stack->previous->state == COMP_OMP_BEGIN_METADIRECTIVE)
+    omp_end_st = ST_OMP_END_METADIRECTIVE;
+
   bool block_construct = false;
   gfc_namespace *my_ns = NULL;
   gfc_namespace *my_parent = NULL;
@@ -5744,13 +5750,6 @@ parse_omp_structured_block (gfc_statement omp_st, bool workshare_stmts_only)
       else
 	st = parse_executable (st);
 
-      /* If handling a metadirective variant, treat 'omp end metadirective'
-	 as the expected end statement for the current construct.  */
-      if (st == ST_OMP_END_METADIRECTIVE
-	  && gfc_state_stack->previous != NULL
-	  && gfc_state_stack->previous->state == COMP_OMP_BEGIN_METADIRECTIVE)
-	st = omp_end_st;
-
       if (st == ST_NONE)
 	unexpected_eof ();
       else if (st == ST_OMP_SECTION
@@ -5863,6 +5862,21 @@ parse_omp_metadirective_body (gfc_statement omp_st)
 	  break;
 	}
 
+      if (gfc_state_stack->state == COMP_OMP_METADIRECTIVE
+	  && startswith (gfc_ascii_statement (st), "!$OMP END "))
+	{
+	  for (gfc_state_data *p = gfc_state_stack; p; p = p->previous)
+	    if (p->state == COMP_OMP_STRUCTURED_BLOCK
+		|| p->state == COMP_OMP_BEGIN_METADIRECTIVE)
+	      goto finish;
+	  gfc_error (
+	    "Unexpected %s statement in an OMP METADIRECTIVE block at %C",
+	    gfc_ascii_statement (st));
+	  reject_statement ();
+	  st = next_statement ();
+	}
+    finish:
+
       gfc_in_metadirective_body = old_in_metadirective_body;
 
       if (gfc_state_stack->head)
diff --git gcc/testsuite/ChangeLog.omp gcc/testsuite/ChangeLog.omp
index e0c8c138620..f0d1b1a388b 100644
--- gcc/testsuite/ChangeLog.omp
+++ gcc/testsuite/ChangeLog.omp
@@ -1,3 +1,10 @@
+2022-09-21  Paul-Antoine Arras  <pa@codesourcery.com>
+
+	* gfortran.dg/gomp/metadirective-1.f90: Match !$OMP END METADIRECTIVE.
+	* gfortran.dg/gomp/metadirective-10.f90: New test.
+	* gfortran.dg/gomp/metadirective-11.f90: New test.
+	* gfortran.dg/gomp/metadirective-9.f90: New test.
+
 2022-09-09  Paul-Antoine Arras  <pa@codesourcery.com>
 
 	Backport from mainline:
diff --git gcc/testsuite/gfortran.dg/gomp/metadirective-1.f90 gcc/testsuite/gfortran.dg/gomp/metadirective-1.f90
index aa439fc855e..ca62aecad89 100644
--- gcc/testsuite/gfortran.dg/gomp/metadirective-1.f90
+++ gcc/testsuite/gfortran.dg/gomp/metadirective-1.f90
@@ -37,5 +37,5 @@ program main
     do i = 1, N
       c(i) = a(i) * b(i)
     end do
-  !$omp end metadirective ! { dg-error "Unexpected !OMP END METADIRECTIVE statement at .1." }
+  !$omp end metadirective ! { dg-error "Unexpected !.OMP END METADIRECTIVE statement at .1." }
 end program
diff --git gcc/testsuite/gfortran.dg/gomp/metadirective-10.f90 gcc/testsuite/gfortran.dg/gomp/metadirective-10.f90
new file mode 100644
index 00000000000..5dad5d29eb6
--- /dev/null
+++ gcc/testsuite/gfortran.dg/gomp/metadirective-10.f90
@@ -0,0 +1,40 @@
+! { dg-do compile }
+
+program metadirectives
+   implicit none
+   logical :: UseDevice
+
+   !$OMP metadirective &
+   !$OMP   when ( user = { condition ( UseDevice ) } &
+   !$OMP     : parallel ) &
+   !$OMP   default ( parallel )
+   block
+      call bar()
+   end block
+
+   !$OMP metadirective &
+   !$OMP   when ( user = { condition ( UseDevice ) } &
+   !$OMP     : parallel ) &
+   !$OMP   default ( parallel )
+   call bar()
+   !$omp end parallel  ! Accepted, because all cases have 'parallel'
+   
+   !$OMP begin metadirective &
+   !$OMP   when ( user = { condition ( UseDevice ) } &
+   !$OMP     : nothing ) &
+   !$OMP   default ( parallel )
+   call bar()
+   block
+      call foo()
+   end block
+   !$OMP end metadirective
+
+   !$OMP begin metadirective &
+   !$OMP   when ( user = { condition ( UseDevice ) } &
+   !$OMP     : parallel ) &
+   !$OMP   default ( parallel )
+   call bar()
+   !$omp end parallel  ! { dg-error "Unexpected !.OMP END PARALLEL statement at .1." }
+end program ! { dg-error "Unexpected END statement at .1." }
+
+! { dg-error "Unexpected end of file" "" { target *-*-* } 0 }
diff --git gcc/testsuite/gfortran.dg/gomp/metadirective-11.f90 gcc/testsuite/gfortran.dg/gomp/metadirective-11.f90
new file mode 100644
index 00000000000..e7de70e6259
--- /dev/null
+++ gcc/testsuite/gfortran.dg/gomp/metadirective-11.f90
@@ -0,0 +1,33 @@
+! { dg-do compile }
+! { dg-ice "Statements following a block in a metadirective" }
+! PR fortran/107067
+
+program metadirectives
+   implicit none
+   logical :: UseDevice
+
+   !$OMP begin metadirective &
+   !$OMP   when ( user = { condition ( UseDevice ) } &
+   !$OMP     : nothing ) &
+   !$OMP   default ( parallel )
+   block
+      call foo()
+   end block
+   call bar()   ! FIXME/XFAIL ICE in parse_omp_metadirective_body()
+   !$omp end metadirective
+
+
+   !$OMP begin metadirective &
+   !$OMP   when ( user = { condition ( UseDevice ) } &
+   !$OMP     : nothing ) &
+   !$OMP   default ( parallel )
+   block
+      call bar()
+   end block
+   block        ! FIXME/XFAIL ICE in parse_omp_metadirective_body()
+      call foo()
+   end block
+   !$omp end metadirective
+end program
+
+
diff --git gcc/testsuite/gfortran.dg/gomp/metadirective-9.f90 gcc/testsuite/gfortran.dg/gomp/metadirective-9.f90
new file mode 100644
index 00000000000..e6ab3fc0a65
--- /dev/null
+++ gcc/testsuite/gfortran.dg/gomp/metadirective-9.f90
@@ -0,0 +1,30 @@
+! { dg-do compile }
+
+program OpenMP_Metadirective_WrongEnd_Test
+  implicit none
+
+  integer :: &
+  iaVS, iV, jV, kV
+  integer, dimension ( 3 ) :: &
+    lV, uV
+  logical :: &
+    UseDevice
+
+    !$OMP metadirective &
+    !$OMP   when ( user = { condition ( UseDevice ) } &
+    !$OMP     : target teams distribute parallel do simd collapse ( 3 ) &
+    !$OMP         private ( iaVS ) ) &
+    !$OMP   default ( parallel do simd collapse ( 3 ) private ( iaVS ) )
+    do kV = lV ( 3 ), uV ( 3 )
+      do jV = lV ( 2 ), uV ( 2 )
+        do iV = lV ( 1 ), uV ( 1 )
+
+
+        end do
+      end do
+    end do
+    !$OMP end target teams distribute parallel do simd ! { dg-error "Unexpected !.OMP END TARGET TEAMS DISTRIBUTE PARALLEL DO SIMD statement in an OMP METADIRECTIVE block at .1." }
+
+
+end program
+
-- 
2.31.1