[debug] Add debug and earlydebug dumps

With the introduction of early debug, we've added a phase in the compiler which
produces information which is not visible, unless we run the compiler in the
debugger and call debug_dwarf from dwarf2out_early_finish or some such.

This patch adds dumping of "early" and "final" debug info, into .earlydebug
and .debug dump files, enabled by -fdump-earlydebug and -fdumpdebug, such that
we can follow f.i. the upper bound of a vla type from early debug:
...
          DW_AT_upper_bound: location descriptor:
            (0x7f0d645b7550) DW_OP_GNU_variable_value , 0
...
to final debug:
...
          DW_AT_upper_bound: location descriptor:
            (0x7f0d645b7550) DW_OP_fbreg 18446744073709551592, 0
            (0x7f0d645b7a00) DW_OP_deref 8, 0
...
to -dA annotated assembly file:
...
        .uleb128 0x3    # DW_AT_upper_bound
        .byte   0x91    # DW_OP_fbreg
        .sleb128 -24
        .byte   0x6     # DW_OP_deref
...

The .debug file shows the same information as the annotated assembly, but in
the same format as the "early" debug info.

Bootstrapped and reg-tested on x86_64.

2018-08-21  Tom de Vries  <tdevries@suse.de>

	* cgraph.h (debuginfo_early_init, debuginfo_init, debuginfo_fini)
	(debuginfo_start, debuginfo_stop, debuginfo_early_start)
	(debuginfo_early_stop): Declare.
	* cgraphunit.c (debuginfo_early_init, debuginfo_init, debuginfo_fini)
	(debuginfo_start, debuginfo_stop, debuginfo_early_start)
	(debuginfo_early_stop): New function.
	(symbol_table::finalize_compilation_unit): Call debuginfo_early_start
	and debuginfo_early_stop.
	* dwarf2out.c (dwarf2out_finish, dwarf2out_early_finish): Dump dwarf.
	* toplev.c (compile_file): Call debuginfo_start and debuginfo_stop.
	(general_init): Call debuginfo_early_init.
	(finalize): Call debuginfo_fini.
	(do_compile): Call debuginfo_init.
	* doc/invoke.texi (@gccoptlist): Add -fdump-debug and
	-fdump-early-debug.
	(@item -fdump-debug, @item -fdump-earlydebug): Add.

	* lto.c (lto_main):  Call debuginfo_early_start and
	debuginfo_early_stop.

	* gcc.c-torture/unsorted/dump-noaddr.x: Use -gno-record-gcc-switches
	to avoid mismatch in .debug and .earlydebug dump files.

From-SVN: r263687

1 files changed, 85 insertions, 0 deletions

diff --git a/gcc/cgraphunit.c b/gcc/cgraphunit.c
index 208798f0dc7..ec490d75bd1 100644
--- a/gcc/cgraphunit.c
+++ b/gcc/cgraphunit.c
@@ -2641,6 +2641,89 @@ symbol_table::compile (void)
     }
 }
 
+/* Earlydebug dump file, flags, and number.  */
+
+static int debuginfo_early_dump_nr;
+static FILE *debuginfo_early_dump_file;
+static dump_flags_t debuginfo_early_dump_flags;
+
+/* Debug dump file, flags, and number.  */
+
+static int debuginfo_dump_nr;
+static FILE *debuginfo_dump_file;
+static dump_flags_t debuginfo_dump_flags;
+
+/* Register the debug and earlydebug dump files.  */
+
+void
+debuginfo_early_init (void)
+{
+  gcc::dump_manager *dumps = g->get_dumps ();
+  debuginfo_early_dump_nr = dumps->dump_register (".earlydebug", "earlydebug",
+						  "earlydebug", DK_tree,
+						  OPTGROUP_NONE,
+						  false);
+  debuginfo_dump_nr = dumps->dump_register (".debug", "debug",
+					     "debug", DK_tree,
+					     OPTGROUP_NONE,
+					     false);
+}
+
+/* Initialize the debug and earlydebug dump files.  */
+
+void
+debuginfo_init (void)
+{
+  gcc::dump_manager *dumps = g->get_dumps ();
+  debuginfo_dump_file = dump_begin (debuginfo_dump_nr, NULL);
+  debuginfo_dump_flags = dumps->get_dump_file_info (debuginfo_dump_nr)->pflags;
+  debuginfo_early_dump_file = dump_begin (debuginfo_early_dump_nr, NULL);
+  debuginfo_early_dump_flags
+    = dumps->get_dump_file_info (debuginfo_early_dump_nr)->pflags;
+}
+
+/* Finalize the debug and earlydebug dump files.  */
+
+void
+debuginfo_fini (void)
+{
+  if (debuginfo_dump_file)
+    dump_end (debuginfo_dump_nr, debuginfo_dump_file);
+  if (debuginfo_early_dump_file)
+    dump_end (debuginfo_early_dump_nr, debuginfo_early_dump_file);
+}
+
+/* Set dump_file to the debug dump file.  */
+
+void
+debuginfo_start (void)
+{
+  set_dump_file (debuginfo_dump_file);
+}
+
+/* Undo setting dump_file to the debug dump file.  */
+
+void
+debuginfo_stop (void)
+{
+  set_dump_file (NULL);
+}
+
+/* Set dump_file to the earlydebug dump file.  */
+
+void
+debuginfo_early_start (void)
+{
+  set_dump_file (debuginfo_early_dump_file);
+}
+
+/* Undo setting dump_file to the earlydebug dump file.  */
+
+void
+debuginfo_early_stop (void)
+{
+  set_dump_file (NULL);
+}
 
 /* Analyze the whole compilation unit once it is parsed completely.  */
 
@@ -2696,7 +2779,9 @@ symbol_table::finalize_compilation_unit (void)
 
       /* Clean up anything that needs cleaning up after initial debug
 	 generation.  */
+      debuginfo_early_start ();
       (*debug_hooks->early_finish) (main_input_filename);
+      debuginfo_early_stop ();
     }
 
   /* Finally drive the pass manager.  */