Re: [PATCH 2/2] PR debug/38757 continued. Handle C11, C++11 and C++14.

[Mark Wielaard <mjw at redhat dot com>]

On Fri, 2014-11-21 at 21:34 +0100, Mark Wielaard wrote:
> On Fri, Nov 21, 2014 at 09:28:45AM +0100, Jakub Jelinek wrote:
> > I think best would be to tweak
> >       if (value < 2 || value > 4)
> >         error_at (loc, "dwarf version %d is not supported", value);
> >       else
> >         opts->x_dwarf_version = value;
> > so that we accept value 5 too, and for now, until the
> > most common consumers are changed, use
> >   if (dwarf_version >= 5 /* || !dwarf_strict */)
> > so that
> > - you can actually use it in the test with -gdwarf-5
> > - you can commit it right away
> > - people can start playing with what it will mean to support DWARF5
> > 
> > GCC 4.5 also allowed -gdwarf-4 even when DWARF4 has not been released yet.
> > When there are consumers that can grok it, we can uncomment the
> > || !dwarf_strict.
> 
> That makes sense and would be convenient for me.
> 
> I made the change in opts.c and added some minimal documentation.
> And made sure we only emit the new DWARFv5 language values, but not yet
> anything else (the table header format has changed for debug_info and
> debug_line in v5, but we don't emit new style headers yet). The testcases
> were updated to explicitly add -gdwarf-5.
> 
> > >    else if (strncmp (language_string, "GNU C", 5) == 0)
> > >      {
> > >        language = DW_LANG_C89;
> > >        if (dwarf_version >= 3 || !dwarf_strict)
> > > -	if (strcmp (language_string, "GNU C99") == 0)
> > > -	  language = DW_LANG_C99;
> > > +	{
> > > +	  if (strcmp (language_string, "GNU C89") != 0)
> > > +	    language = DW_LANG_C99;
> > > +
> > > +	  if (dwarf_version >= 5 || !dwarf_strict)
> > > +	    if (strcmp (language_string, "GNU C11") == 0)
> > > +	      language = DW_LANG_C11;
> > > +	}
> > 
> > Shouldn't we emit at least DW_LANG_C99 for GNU C11 if
> > not dwarf_version >= 5 /* || !dwarf_strict */ but
> > dwarf_version >= 3 || !dwarf_strict is true?
> 
> Yes, that is the intention. If it is a versioned GNU C then it is
> at least DW_LANG_C89, if we have -gdwarf-3 or higher and it isn't
> GNU C89 then it is at least DW_LANG_C99 and if we have -gdwarf-5
> and it is GNU C11 then we emit DW_LANG_C11.
> 
> I added an explicit testcase for this.
> 
> > BTW, noticed we don't have anything for Fortran 2003 and 2008,
> > filed a DWARF Issue for that.
> 
> Thanks. I have only focussed on C and C++ because I don't know anything
> about version changes in other language standards.
> 
> With the above change everything keeps working fine. You only need a
> patched GDB when explicitly using -gdwarf-5.
> 
> OK to commit?

Ping. Rebased patch attached.

I have submitted patches for elfutils, valgrind, gdb and binutils for
this. But they are pending till this patch hits GCC first.

Thanks,

Mark

From a9c0a73bc74a7a25edd449cf42d179c16fbc13f4 Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mjw@redhat.com>
Date: Fri, 21 Nov 2014 21:18:00 +0100
Subject: [PATCH] PR debug/38757 continued. Handle C11, C++11 and C++14.

Add experimental (minimal) DWARFv5 support.

This change depends on the new DWARFv5 constants mentioned in the
following draft: http://dwarfstd.org/doc/dwarf5.20141029.pdf

gcc/ChangeLog

	* doc/invoke.texi (-gdwarf-@{version}): Mention experimental DWARFv5.
	* opts.c (common_handle_option): Accept -gdwarf-5.
	* dwarf2out.c (is_cxx): Add DW_LANG_C_plus_plus_11 and
	DW_LANG_C_plus_plus_14.
	(lower_bound_default): Likewise. Plus DW_LANG_C11.
	(gen_compile_unit_die): Output DW_LANG_C_plus_plus_11,
	DW_LANG_C_plus_plus_14 or DW_LANG_C11.
	(output_compilation_unit_header): Output at most a DWARFv4 header.
	(output_skeleton_debug_sections): Likewise.
	(output_line_info): Likewise.
	(output_aranges): Document header version number.

gcc/testsuite/ChangeLog

	* gcc.dg/debug/dwarf2/lang-c11.c: New test.
	* gcc.dg/debug/dwarf2/lang-c11-d4-strict.c: Likewise.
	* g++.dg/debug/dwarf2/lang-cpp11.C: Likewise.
	* g++.dg/debug/dwarf2/lang-cpp14.C: Likewise.
	* g++.dg/debug/dwarf2/lang-cpp98.C: Likewise.

include/ChangeLog

	* dwarf2.h: Add DW_LANG_C_plus_plus_11, DW_LANG_C11 and
	DW_LANG_C_plus_plus_14.
---
 gcc/ChangeLog                                      | 14 +++++++
 gcc/doc/invoke.texi                                |  4 +-
 gcc/dwarf2out.c                                    | 45 +++++++++++++++++-----
 gcc/opts.c                                         |  2 +-
 gcc/testsuite/ChangeLog                            |  8 ++++
 gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp11.C     |  6 +++
 gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp14.C     |  6 +++
 gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp98.C     |  6 +++
 .../gcc.dg/debug/dwarf2/lang-c11-d4-strict.c       |  7 ++++
 gcc/testsuite/gcc.dg/debug/dwarf2/lang-c11.c       |  6 +++
 include/ChangeLog                                  |  5 +++
 include/dwarf2.h                                   |  4 ++
 12 files changed, 101 insertions(+), 12 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp11.C
 create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp14.C
 create mode 100644 gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp98.C
 create mode 100644 gcc/testsuite/gcc.dg/debug/dwarf2/lang-c11-d4-strict.c
 create mode 100644 gcc/testsuite/gcc.dg/debug/dwarf2/lang-c11.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e7845c7..06cdaa4 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,17 @@
+2014-11-21  Mark Wielaard  <mjw@redhat.com>
+
+	* doc/invoke.texi (-gdwarf-@{version}): Mention experimental DWARFv5.
+	* opts.c (common_handle_option): Accept -gdwarf-5.
+	* dwarf2out.c (is_cxx): Add DW_LANG_C_plus_plus_11 and
+	DW_LANG_C_plus_plus_14.
+	(lower_bound_default): Likewise. Plus DW_LANG_C11.
+	(gen_compile_unit_die): Output DW_LANG_C_plus_plus_11,
+	DW_LANG_C_plus_plus_14 or DW_LANG_C11.
+	(output_compilation_unit_header): Output at most a DWARFv4 header.
+	(output_skeleton_debug_sections): Likewise.
+	(output_line_info): Likewise.
+	(output_aranges): Document header version number.
+
 2014-11-25  Mark Wielaard  <mjw@redhat.com>
 
 	* dwarf2out.c (gen_subprogram_die): Add DW_AT_noreturn when the
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 89edddb..d7bce2a 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -5407,8 +5407,8 @@ assembler (GAS) to fail with an error.
 @item -gdwarf-@var{version}
 @opindex gdwarf-@var{version}
 Produce debugging information in DWARF format (if that is supported).
-The value of @var{version} may be either 2, 3 or 4; the default version
-for most targets is 4.
+The value of @var{version} may be either 2, 3, 4 or 5; the default version
+for most targets is 4.  DWARF Version 5 is only experimental.
 
 Note that with DWARF Version 2, some ports require and always
 use some non-conflicting DWARF 3 extensions in the unwind tables.
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 25307d2..25f0e7d 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -4684,7 +4684,8 @@ is_cxx (void)
 {
   unsigned int lang = get_AT_unsigned (comp_unit_die (), DW_AT_language);
 
-  return lang == DW_LANG_C_plus_plus || lang == DW_LANG_ObjC_plus_plus;
+  return (lang == DW_LANG_C_plus_plus || lang == DW_LANG_ObjC_plus_plus
+	  || lang == DW_LANG_C_plus_plus_11 || lang == DW_LANG_C_plus_plus_14);
 }
 
 /* Return TRUE if the language is Java.  */
@@ -8966,7 +8967,9 @@ output_die (dw_die_ref die)
 static void
 output_compilation_unit_header (void)
 {
-  int ver = dwarf_version;
+  /* We don't support actual DWARFv5 units yet, we just use some
+     DWARFv5 draft DIE tags in DWARFv4 format.  */
+  int ver = dwarf_version < 5 ? dwarf_version : 4;
 
   if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
     dw2_asm_output_data (4, 0xffffffff,
@@ -9109,6 +9112,10 @@ add_top_level_skeleton_die_attrs (dw_die_ref die)
 static void
 output_skeleton_debug_sections (dw_die_ref comp_unit)
 {
+  /* We don't support actual DWARFv5 units yet, we just use some
+     DWARFv5 draft DIE tags in DWARFv4 format.  */
+  int ver = dwarf_version < 5 ? dwarf_version : 4;
+
   /* These attributes will be found in the full debug_info section.  */
   remove_AT (comp_unit, DW_AT_producer);
   remove_AT (comp_unit, DW_AT_language);
@@ -9128,7 +9135,7 @@ output_skeleton_debug_sections (dw_die_ref comp_unit)
                        - DWARF_INITIAL_LENGTH_SIZE
                        + size_of_die (comp_unit),
                       "Length of Compilation Unit Info");
-  dw2_asm_output_data (2, dwarf_version, "DWARF version number");
+  dw2_asm_output_data (2, ver, "DWARF version number");
   dw2_asm_output_offset (DWARF_OFFSET_SIZE, debug_skeleton_abbrev_section_label,
                          debug_abbrev_section,
                          "Offset Into Abbrev. Section");
@@ -9481,7 +9488,7 @@ output_aranges (unsigned long aranges_length)
       "Initial length escape value indicating 64-bit DWARF extension");
   dw2_asm_output_data (DWARF_OFFSET_SIZE, aranges_length,
 		       "Length of Address Ranges Info");
-  /* Version number for aranges is still 2, even in DWARF3.  */
+  /* Version number for aranges is still 2, even up to DWARF5.  */
   dw2_asm_output_data (2, 2, "DWARF Version");
   if (dwarf_split_debug_info)
     dw2_asm_output_offset (DWARF_OFFSET_SIZE, debug_skeleton_info_section_label,
@@ -10156,7 +10163,8 @@ static void
 output_line_info (bool prologue_only)
 {
   char l1[20], l2[20], p1[20], p2[20];
-  int ver = dwarf_version;
+  /* We don't support DWARFv5 line tables yet.  */
+  int ver = dwarf_version < 5 ? dwarf_version : 4;
   bool saw_one = false;
   int opc;
 
@@ -16402,7 +16410,10 @@ lower_bound_default (void)
     case DW_LANG_C:
     case DW_LANG_C89:
     case DW_LANG_C99:
+    case DW_LANG_C11:
     case DW_LANG_C_plus_plus:
+    case DW_LANG_C_plus_plus_11:
+    case DW_LANG_C_plus_plus_14:
     case DW_LANG_ObjC:
     case DW_LANG_ObjC_plus_plus:
     case DW_LANG_Java:
@@ -16746,6 +16757,7 @@ add_prototyped_attribute (dw_die_ref die, tree func_type)
     case DW_LANG_C:
     case DW_LANG_C89:
     case DW_LANG_C99:
+    case DW_LANG_C11:
     case DW_LANG_ObjC:
       if (prototype_p (func_type))
 	add_AT_flag (die, DW_AT_prototyped, 1);
@@ -19595,15 +19607,30 @@ gen_compile_unit_die (const char *filename)
 
   language = DW_LANG_C;
   if (strncmp (language_string, "GNU C", 5) == 0
-      && (language_string[5] == 0 || ISDIGIT (language_string[5])))
+      && ISDIGIT (language_string[5]))
     {
       language = DW_LANG_C89;
       if (dwarf_version >= 3 || !dwarf_strict)
-	if (strcmp (language_string, "GNU C99") == 0)
-	  language = DW_LANG_C99;
+	{
+	  if (strcmp (language_string, "GNU C89") != 0)
+	    language = DW_LANG_C99;
+
+	  if (dwarf_version >= 5 /* || !dwarf_strict */)
+	    if (strcmp (language_string, "GNU C11") == 0)
+	      language = DW_LANG_C11;
+	}
     }
   else if (strncmp (language_string, "GNU C++", 7) == 0)
-    language = DW_LANG_C_plus_plus;
+    {
+      language = DW_LANG_C_plus_plus;
+      if (dwarf_version >= 5 /* || !dwarf_strict */)
+	{
+	  if (strcmp (language_string, "GNU C++11") == 0)
+	    language = DW_LANG_C_plus_plus_11;
+	  else if (strcmp (language_string, "GNU C++14") == 0)
+	    language = DW_LANG_C_plus_plus_14;
+	}
+    }
   else if (strcmp (language_string, "GNU F77") == 0)
     language = DW_LANG_Fortran77;
   else if (strcmp (language_string, "GNU Pascal") == 0)
diff --git a/gcc/opts.c b/gcc/opts.c
index f3deb40..3a0ed61 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -1992,7 +1992,7 @@ common_handle_option (struct gcc_options *opts,
       
       /* FALLTHRU */
     case OPT_gdwarf_:
-      if (value < 2 || value > 4)
+      if (value < 2 || value > 5)
 	error_at (loc, "dwarf version %d is not supported", value);
       else
 	opts->x_dwarf_version = value;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 429885c..1872046 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2014-11-21  Mark Wielaard  <mjw@redhat.com>
+
+	* gcc.dg/debug/dwarf2/lang-c11.c: New test.
+	* gcc.dg/debug/dwarf2/lang-c11-d4-strict.c: Likewise.
+	* g++.dg/debug/dwarf2/lang-cpp11.C: Likewise.
+	* g++.dg/debug/dwarf2/lang-cpp14.C: Likewise.
+	* g++.dg/debug/dwarf2/lang-cpp98.C: Likewise.
+
 2014-11-24  Mark Wielaard  <mjw@redhat.com>
 
 	* g++.dg/debug/dwarf2/noreturn-function.C: New test.
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp11.C b/gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp11.C
new file mode 100644
index 0000000..8079c0e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp11.C
@@ -0,0 +1,6 @@
+// { dg-do compile }
+// { dg-options "-O -std=c++11 -gdwarf-5 -dA" }
+// DW_LANG_C_plus_plus_11 = 0x001a
+// { dg-final { scan-assembler "0x1a.*DW_AT_language" } } */
+
+int version;
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp14.C b/gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp14.C
new file mode 100644
index 0000000..448ec7c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp14.C
@@ -0,0 +1,6 @@
+// { dg-do compile }
+// { dg-options "-O -std=c++14 -gdwarf-5 -dA" }
+// DW_LANG_C_plus_plus_14 = 0x0021
+// { dg-final { scan-assembler "0x21.*DW_AT_language" } } */
+
+int version;
diff --git a/gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp98.C b/gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp98.C
new file mode 100644
index 0000000..065cc18
--- /dev/null
+++ b/gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp98.C
@@ -0,0 +1,6 @@
+// { dg-do compile }
+// { dg-options "-O -std=c++98 -g -dA" }
+// DW_LANG_C_plus_plus = 0x0004
+// { dg-final { scan-assembler "0x4.*DW_AT_language" } } */
+
+int version;
diff --git a/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c11-d4-strict.c b/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c11-d4-strict.c
new file mode 100644
index 0000000..accc13f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c11-d4-strict.c
@@ -0,0 +1,7 @@
+// { dg-do compile }
+// { dg-options "-O -std=c11 -gdwarf-4 -gstrict-dwarf -dA" }
+// We cannot produce DW_LANG_C11 = 0x001d because strict-dwarf.
+// So expect DW_LANG_C99 = 0x000c
+// { dg-final { scan-assembler "0xc.*DW_AT_language" } } */
+
+int version;
diff --git a/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c11.c b/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c11.c
new file mode 100644
index 0000000..f14c49f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c11.c
@@ -0,0 +1,6 @@
+// { dg-do compile }
+// { dg-options "-O -std=c11 -gdwarf-5 -dA" }
+// DW_LANG_C11 = 0x001d
+// { dg-final { scan-assembler "0x1d.*DW_AT_language" } } */
+
+int version;
diff --git a/include/ChangeLog b/include/ChangeLog
index e73a9a8..e0baca9 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,8 @@
+2014-11-21  Mark Wielaard  <mjw@redhat.com>
+
+	* dwarf2.h: Add DW_LANG_C_plus_plus_11, DW_LANG_C11 and
+	DW_LANG_C_plus_plus_14.
+
 2014-11-25  Mark Wielaard  <mjw@redhat.com>
 
 	* dwarf2.def (DW_AT_noreturn): New DWARF5 attribute.
diff --git a/include/dwarf2.h b/include/dwarf2.h
index 120e2c1..ca440dd 100644
--- a/include/dwarf2.h
+++ b/include/dwarf2.h
@@ -309,6 +309,10 @@ enum dwarf_source_language
     /* DWARF 5.  */
     DW_LANG_Go = 0x0016,
 
+    DW_LANG_C_plus_plus_11 = 0x001a, /* dwarf5.20141029.pdf DRAFT */
+    DW_LANG_C11 = 0x001d,
+    DW_LANG_C_plus_plus_14 = 0x0021,
+
     DW_LANG_lo_user = 0x8000,	/* Implementation-defined range start.  */
     DW_LANG_hi_user = 0xffff,	/* Implementation-defined range start.  */
 
-- 
1.8.3.1