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[PATCH] PR debug/38757 gcc does not emit DW_LANG_C99


Hi,

This patch was written a long time ago by Jakub and has been in Fedora
gcc for some time. All I did was rebase it to current gcc trunk
and add a testcase. Back when it was originally proposed the issue was
that because DWARF was generated late adding new lang hooks for this
was problematic for LTO. Now that there is a move towards generating
DWARF early I am hoping this patch can finally make it to mainline gcc.

This lang hook will be more useful when DWARFv5 gets out, which is
supposed to define language identifiers for newer C and C++ versions.

Previous discussions:
http://gcc.gnu.org/ml/gcc-patches/2009-03/msg00858.html
http://gcc.gnu.org/ml/gcc-patches/2010-04/msg00991.html

gcc/ChangeLog

2009-03-18  Jakub Jelinek  <jakub@redhat.com>

	PR debug/38757
	* langhooks.h (struct lang_hooks): Add source_language langhook.
	* langhooks-def.h (LANG_HOOKS_SOURCE_LANGUAGE): Define to NULL.
	(LANG_HOOKS_INITIALIZER): Add LANG_HOOKS_SOURCE_LANGUAGE.
	* dwarf2out.c (add_prototyped_attribute): Add DW_AT_prototype
	also for DW_LANG_{C,C99,ObjC}.
	(gen_compile_unit_die): Use lang_hooks.source_language () to
	determine if DW_LANG_C99 or DW_LANG_C89 should be returned.

gcc/c/ChangeLog

2009-03-18  Jakub Jelinek  <jakub@redhat.com>

	PR debug/38757
	* c-lang.c (c_source_language): New function.
	(LANG_HOOKS_SOURCE_LANGUAGE): Define.

gcc/testsuite/ChangeLog

2014-10-08  Mark Wielaard  <mjw@redhat.com>

	PR debug/38757
	* gcc.dg/debug/dwarf2/lang-c89.c: New test.
	* gcc.dg/debug/dwarf2/lang-c99.c: Likewise.
---
 gcc/ChangeLog                                | 11 +++++++++++
 gcc/c/ChangeLog                              |  6 ++++++
 gcc/c/c-lang.c                               |  8 ++++++++
 gcc/dwarf2out.c                              | 19 ++++++++++++++++---
 gcc/langhooks-def.h                          |  4 +++-
 gcc/langhooks.h                              |  4 ++++
 gcc/testsuite/ChangeLog                      |  6 ++++++
 gcc/testsuite/gcc.dg/debug/dwarf2/lang-c89.c |  6 ++++++
 gcc/testsuite/gcc.dg/debug/dwarf2/lang-c99.c |  6 ++++++
 9 files changed, 66 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/debug/dwarf2/lang-c89.c
 create mode 100644 gcc/testsuite/gcc.dg/debug/dwarf2/lang-c99.c

diff --git a/gcc/c/c-lang.c b/gcc/c/c-lang.c
index 97c0443..dadeb1a 100644
--- a/gcc/c/c-lang.c
+++ b/gcc/c/c-lang.c
@@ -35,6 +35,12 @@ along with GCC; see the file COPYING3.  If not see
 
 enum c_language_kind c_language = clk_c;
 
+static int
+c_source_language (void)
+{
+  return flag_isoc99 ? 1999 : 1989;
+}
+
 /* Lang hooks common to C and ObjC are declared in c-objc-common.h;
    consequently, there should be very few hooks below.  */
 
@@ -44,6 +50,8 @@ enum c_language_kind c_language = clk_c;
 #define LANG_HOOKS_INIT c_objc_common_init
 #undef LANG_HOOKS_INIT_TS
 #define LANG_HOOKS_INIT_TS c_common_init_ts
+#undef LANG_HOOKS_SOURCE_LANGUAGE
+#define LANG_HOOKS_SOURCE_LANGUAGE c_source_language
 
 /* Each front end provides its own lang hook initializer.  */
 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 59c05ed..4932cd0 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -16708,9 +16708,18 @@ add_bit_size_attribute (dw_die_ref die, tree decl)
 static inline void
 add_prototyped_attribute (dw_die_ref die, tree func_type)
 {
-  if (get_AT_unsigned (comp_unit_die (), DW_AT_language) == DW_LANG_C89
-      && prototype_p (func_type))
-    add_AT_flag (die, DW_AT_prototyped, 1);
+  switch (get_AT_unsigned (comp_unit_die (), DW_AT_language))
+    {
+    case DW_LANG_C:
+    case DW_LANG_C89:
+    case DW_LANG_C99:
+    case DW_LANG_ObjC:
+      if (prototype_p (func_type))
+	add_AT_flag (die, DW_AT_prototyped, 1);
+      break;
+    default:
+      break;
+    }
 }
 
 /* Add an 'abstract_origin' attribute below a given DIE.  The DIE is found
@@ -19544,6 +19553,10 @@ gen_compile_unit_die (const char *filename)
 	language = DW_LANG_ObjC;
       else if (strcmp (language_string, "GNU Objective-C++") == 0)
 	language = DW_LANG_ObjC_plus_plus;
+      else if (strcmp (language_string, "GNU C") == 0
+	       && lang_hooks.source_language
+	       && lang_hooks.source_language () >= 1999)
+	language = DW_LANG_C99;
       else if (dwarf_version >= 5 || !dwarf_strict)
 	{
 	  if (strcmp (language_string, "GNU Go") == 0)
diff --git a/gcc/langhooks-def.h b/gcc/langhooks-def.h
index e5ae3e3..b6c8dd4 100644
--- a/gcc/langhooks-def.h
+++ b/gcc/langhooks-def.h
@@ -120,6 +120,7 @@ extern bool lhd_omp_mappable_type (tree);
 #define LANG_HOOKS_BLOCK_MAY_FALLTHRU	hook_bool_const_tree_true
 #define LANG_HOOKS_EH_USE_CXA_END_CLEANUP	false
 #define LANG_HOOKS_DEEP_UNSHARING	false
+#define LANG_HOOKS_SOURCE_LANGUAGE	NULL
 
 /* Attribute hooks.  */
 #define LANG_HOOKS_ATTRIBUTE_TABLE		NULL
@@ -313,7 +314,8 @@ extern void lhd_end_section (void);
   LANG_HOOKS_EH_PROTECT_CLEANUP_ACTIONS, \
   LANG_HOOKS_BLOCK_MAY_FALLTHRU, \
   LANG_HOOKS_EH_USE_CXA_END_CLEANUP, \
-  LANG_HOOKS_DEEP_UNSHARING \
+  LANG_HOOKS_DEEP_UNSHARING, \
+  LANG_HOOKS_SOURCE_LANGUAGE \
 }
 
 #endif /* GCC_LANG_HOOKS_DEF_H */
diff --git a/gcc/langhooks.h b/gcc/langhooks.h
index 32e76f9..0022516 100644
--- a/gcc/langhooks.h
+++ b/gcc/langhooks.h
@@ -485,6 +485,10 @@ struct lang_hooks
      gimplification.  */
   bool deep_unsharing;
 
+  /* Return year of the source language standard version if the FE supports
+     multiple versions of the standard.  */
+  int (*source_language) (void);
+
   /* Whenever you add entries here, make sure you adjust langhooks-def.h
      and langhooks.c accordingly.  */
 };
diff --git a/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c89.c b/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c89.c
new file mode 100644
index 0000000..6292cf8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c89.c
@@ -0,0 +1,6 @@
+/* { dg-do compile } */
+/* { dg-options "-O -std=c89 -g -dA" } */
+/* DW_LANG_C89 = 0x0001 */
+/* { dg-final { scan-assembler "0x1.*DW_AT_language" } } */
+
+int version;
diff --git a/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c99.c b/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c99.c
new file mode 100644
index 0000000..1d789fe
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/debug/dwarf2/lang-c99.c
@@ -0,0 +1,6 @@
+// { dg-do compile }
+// { dg-options "-O -std=c99 -g -dA" }
+// DW_LANG_C99 = 0x000c
+// { dg-final { scan-assembler "0xc.*DW_AT_language" } } */
+
+int version;
-- 
1.8.3.1


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