Stop Gas from generating line info or address ranges for sections that do not contain code or are not loaded.

PR 26850
	* dwarf2dbg.c (dwarf2_gen_line_info_1): Do not record lines in
	sections that are not executable or not loadable.
	(out_debug_line): Move warning message into dwarf2_gen_line_info_1.
	* testsuite/gas/elf/dwarf2-20.s: New test.
	* testsuite/gas/elf/dwarf2-20.d: New test driver.
	* testsuite/gas/elf/elf.exp: Run the new test.
	* testsuite/gas/elf/warn-2.s: Use the .nop directive.

gas/ChangeLog

@@ -1,3 +1,12 @@
+2020-11-12  Nick Clifton  <nickc@redhat.com>
+
+	PR 26850
+	* dwarf2dbg.c
+	* testsuite/gas/elf/dwarf2-20.s: New test.
+	* testsuite/gas/elf/dwarf2-20.d: New test driver.
+	* testsuite/gas/elf/elf.exp: Run the new test.
+	* testsuite/gas/elf/warn-2.s
+
 2020-11-11  Przemyslaw Wirkus  <przemyslaw.wirkus@arm.com>
 
 	* testsuite/gas/aarch64/ls64.s: Update test.

gas/dwarf2dbg.c

@@ -504,6 +504,18 @@ dwarf2_gen_line_info_1 (symbolS *label, struct dwarf2_line_info *loc)
 {
   struct line_subseg *lss;
   struct line_entry *e;
+  flagword need_flags = SEC_ALLOC | SEC_LOAD | SEC_CODE;
+
+  /* PR 26850: Do not record LOCs in non-executable, non-allocated,
+     or non-loaded sections.  */
+  if ((now_seg->flags & need_flags) != need_flags)
+    {
+      if (! SEG_NORMAL (now_seg))
+	/* FIXME: Add code to suppress multiple warnings ?  */
+	as_warn ("dwarf line number information for %s ignored",
+		 segment_name (now_seg));
+      return;
+    }
 
   e = XNEW (struct line_entry);
   e->next = NULL;
@@ -2341,11 +2353,10 @@ out_debug_line (segT line_seg)
 
   /* For each section, emit a statement program.  */
   for (s = all_segs; s; s = s->next)
+    /* Paranoia - this check should have already have
+       been handled in dwarf2_gen_line_info_1().  */
     if (SEG_NORMAL (s->seg))
       process_entries (s->seg, s->head->head);
-    else
-      as_warn ("dwarf line number information for %s ignored",
-	       segment_name (s->seg));
 
   if (flag_dwarf_sections)
     /* We have to switch to the special .debug_line_end section
@@ -2740,7 +2751,6 @@ dwarf2_init (void)
     flag_dwarf_cie_version = 1;
 }
 
-
 /* Finish the dwarf2 debug sections.  We emit .debug.line if there
    were any .file/.loc directives, or --gdwarf2 was given, and if the
    file has a non-empty .debug_info section and an empty .debug_line

gas/testsuite/gas/elf/dwarf2-20.d

@@ -0,0 +1,18 @@
+#as: -gdwarf-3
+#readelf: -wr
+#name: DWARF2_20: debug ranges ignore non-code sections
+# The mn10200 target has a pointer size of 3, but it does not use segment selectors.  This confuses DWARF and readelf will complain.
+#xfail: mn102*-*
+
+Contents of the .debug_aranges section:
+
+[ 	]+Length:[ 	]+(16|28|44)
+[ 	]+Version:.*
+[ 	]+Offset into .debug_info:[ 	]+0x0
+[ 	]+Pointer Size:[ 	]+(2|4|8)
+[ 	]+Segment Size:[ 	]+0
+
+[ 	]+Address[ 	]+Length
+[ 	]+0+000 0+00. 
+[ 	]+0+000 0+000 
+#pass

gas/testsuite/gas/elf/dwarf2-20.s

@@ -0,0 +1,10 @@
+	.section .alloc0,"a"
+	.nop
+	.section .alloc1,"a"
+	.nop
+	.section .nonalloc,""
+	.nop
+	.section .allocexec,"ax"
+	.nop
+	.section .nonallocexec,"x"
+	.nop

gas/testsuite/gas/elf/elf.exp

@@ -282,6 +282,7 @@ if { [is_elf_format] } then {
     run_dump_test "dwarf2-17" $dump_opts
     run_dump_test "dwarf2-18" $dump_opts
     run_dump_test "dwarf2-19" $dump_opts
+    run_dump_test "dwarf2-20" $dump_opts
     run_dump_test "dwarf-5-file0" $dump_opts
     run_dump_test "dwarf-4-cu" $dump_opts
     run_dump_test "dwarf-5-cu" $dump_opts

gas/testsuite/gas/elf/warn-2.s

@@ -1,18 +1,7 @@
 ;# { dg-do assemble }
-;# { dg-options "--gdwarf2 --defsym nop_type=0" }
-;# { dg-options "--gdwarf2 --defsym nop_type=1" { target ia64-*-* } }
-;# { dg-options "--gdwarf2 --defsym nop_type=2" { target or1k*-*-* } }
+;# { dg-options "--gdwarf2" }
 
 	.offset 40
-	
- .ifeq nop_type - 1
-	nop 0
- .else
- .ifeq nop_type - 2
-	l.nop 0
- .else
-	nop
- .endif
- .endif
+	.nop
 
 ;# { dg-warning "Warning: dwarf line number information for .* ignored" "" { xfail v850*-*-* } 0 }