Fix fortran common-related error recovery ICE.

Upon reverting a symbol in a common block (after throwing an error),
the compiler was ICEing because the symbol's common_block field was set,
but the symbol was not in the common block's list of symbols.

Fixed by both adding the symbol to the common block list and setting
the symbol's common_block field at the same time.
Furthermore, the gfc_add_in_common call is delayed and its result is
ignored, so that its error messages are ignored and the compiler has
the opportunity to give a better error message.
Another gfc_add_in_common call is added later during resolution
to emit again the missing errors.

	PR fortran/67758
gcc/fortran/
	* match.c (gfc_match_common): Delay the common_block pointer
	assignment after error checking.
	Delay the call to gfc_add_in_common attribute after the handling
	of array specs.
	* resolve.c (resolve_common_vars): Call gfc_add_in_common again.
gcc/testsuite/
	* gfortran.dg/common_24.f: New.

From-SVN: r228457

5 files changed, 37 insertions, 7 deletions

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 014d67c..cdf27b2 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,5 +1,14 @@
 2015-10-04  Mikael Morin  <mikael@gcc.gnu.org>
 
+	PR fortran/67758
+	* match.c (gfc_match_common): Delay the common_block pointer
+	assignment after error checking.
+	Delay the call to gfc_add_in_common attribute after the handling
+	of array specs.
+	* resolve.c (resolve_common_vars): Call gfc_add_in_common again.
+
+2015-10-04  Mikael Morin  <mikael@gcc.gnu.org>
+
 	* resolve.c (resolve_common_vars): Move access to the common
 	block's head symbol inside the function.
 	(resolve_common_blocks, resolve_types): Update callers.
@@ -102,7 +111,6 @@
 
 	* resolve.c (nonscalar_typebound_assign): Fix typos in comment.
 
-
 2015-09-21  Steven G. Kargl  <kargl@gcc.gnu.org>
 
 	PR fortran/67615
diff --git a/gcc/fortran/match.c b/gcc/fortran/match.c
index a50ec2d..2363004 100644
--- a/gcc/fortran/match.c
+++ b/gcc/fortran/match.c
@@ -4330,10 +4330,6 @@ gfc_match_common (void)
 	  if (m == MATCH_NO)
 	    goto syntax;
 
-          /* Store a ref to the common block for error checking.  */
-          sym->common_block = t;
-          sym->common_block->refs++;
-
           /* See if we know the current common block is bind(c), and if
              so, then see if we can check if the symbol is (which it'll
              need to be).  This can happen if the bind(c) attr stmt was
@@ -4376,8 +4372,8 @@ gfc_match_common (void)
 		goto cleanup;
 	    }
 
-	  if (!gfc_add_in_common (&sym->attr, sym->name, NULL))
-	    goto cleanup;
+	  sym->common_block = t;
+	  sym->common_block->refs++;
 
 	  if (tail != NULL)
 	    tail->common_next = sym;
@@ -4416,6 +4412,10 @@ gfc_match_common (void)
 
 	    }
 
+	  /* Add the in_common attribute, but ignore the reported errors
+	     if any, and continue matching.  */
+	  gfc_add_in_common (&sym->attr, sym->name, NULL);
+
 	  sym->common_head = t;
 
 	  /* Check to see if the symbol is already in an equivalence group.
diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 614d8a9..e75c293 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -918,6 +918,12 @@ resolve_common_vars (gfc_common_head *common_block, bool named_common)
 
   for (; csym; csym = csym->common_next)
     {
+      /* gfc_add_in_common may have been called before, but the reported errors
+	 have been ignored to continue parsing.
+	 We do the checks again here.  */
+      if (!csym->attr.use_assoc)
+	gfc_add_in_common (&csym->attr, csym->name, &common_block->where);
+
       if (csym->value || csym->attr.data)
 	{
 	  if (!csym->ns->is_block_data)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 47b79f0..85d593d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2015-10-04  Mikael Morin  <mikael@gcc.gnu.org>
+
+	PR fortran/67758
+	* gfortran.dg/common_24.f: New.
+
 2015-10-03  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	* gcc.target/arm/pr67756.c: Fixed warnings.
diff --git a/gcc/testsuite/gfortran.dg/common_24.f b/gcc/testsuite/gfortran.dg/common_24.f
new file mode 100644
index 0000000..ea37c2a
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/common_24.f
@@ -0,0 +1,11 @@
+c { dg-do compile }
+c PR fortran/67758
+c
+c Check the absence of ICE after emitting the error message
+c
+c Contributed by Ilya Enkovich <ienkovich@gcc.gnu.org>
+
+      COMMON /FMCOM / X(80 000 000)
+      CALL T(XX(A))
+      COMMON /FMCOM / XX(80 000 000) ! { dg-error "Unexpected COMMON" }
+      END