AArch64: Close sequences at the end of sections

Any open sequence at the end of a section or assembly is considered an error.
This patch adds a check at the end to ensure that all sequences have been closed
and if not reports a warning.

During disassembly it's not possible to detect this condition in the back-end so
the warning is only emitted from the assembler for now.

gas/

	* config/tc-aarch64.c (force_automatic_sequence_close,
	aarch64_frob_section): New.
	* config/tc-aarch64.h (tc_frob_section, aarch64_frob_section): New.

3 files changed, 27 insertions, 0 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index b4cafbb..56609f4 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,5 +1,11 @@
 2018-10-03  Tamar Christina  <tamar.christina@arm.com>
 
+	* config/tc-aarch64.c (force_automatic_sequence_close,
+	aarch64_frob_section): New.
+	* config/tc-aarch64.h (tc_frob_section, aarch64_frob_section): New.
+
+2018-10-03  Tamar Christina  <tamar.christina@arm.com>
+
 	* config/tc-aarch64.c (output_operand_error_report): Order warnings.
 
 2018-10-03  Tamar Christina  <tamar.christina@arm.com>
diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index a5fe6bc..085ffa2 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -6738,6 +6738,17 @@ warn_unpredictable_ldst (aarch64_instruction *instr, char *str)
     }
 }
 
+static void
+force_automatic_sequence_close (void)
+{
+  if (now_instr_sequence.instr)
+    {
+      as_warn (_("previous `%s' sequence has not been closed"),
+	       now_instr_sequence.instr->opcode->name);
+      init_insn_sequence (NULL, &now_instr_sequence);
+    }
+}
+
 /* A wrapper function to interface with libopcodes on encoding and
    record the error message if there is any.
 
@@ -6931,6 +6942,13 @@ aarch64_frob_label (symbolS * sym)
   dwarf2_emit_label (sym);
 }
 
+void
+aarch64_frob_section (asection *sec ATTRIBUTE_UNUSED)
+{
+  /* Check to see if we have a block to close.  */
+  force_automatic_sequence_close ();
+}
+
 int
 aarch64_data_in_code (void)
 {
diff --git a/gas/config/tc-aarch64.h b/gas/config/tc-aarch64.h
index cdf9883..88df2aa 100644
--- a/gas/config/tc-aarch64.h
+++ b/gas/config/tc-aarch64.h
@@ -78,6 +78,8 @@ struct aarch64_fix
 /* We also need to mark assembler created symbols:  */
 #define tc_frob_fake_label(S) aarch64_frob_label (S)
 
+#define tc_frob_section(S) aarch64_frob_section (S)
+
 #define TC_FIX_TYPE struct aarch64_fix
 #define TC_INIT_FIX_DATA(FIX) { (FIX)->tc_fix_data.inst = NULL;	\
     (FIX)->tc_fix_data.opnd = AARCH64_OPND_NIL; }
@@ -218,6 +220,7 @@ extern int aarch64_force_relocation (struct fix *);
 extern void aarch64_cleanup (void);
 extern void aarch64_start_line_hook (void);
 extern void aarch64_frob_label (symbolS *);
+extern void aarch64_frob_section (asection *sec);
 extern int aarch64_data_in_code (void);
 extern char * aarch64_canonicalize_symbol_name (char *);
 extern void aarch64_adjust_symtab (void);