PR/21391

	* testsuite/gcc.dg/20060410.c: New.
	* dwarf2out.c (struct die_struct): Add die_perennial_p field.
	(premark_used_types_helper): New.
	(premark_used_types): New.
	(gen_subprogram_die): Call premark_used_types.
	(prune_unused_types_walk): Do not prune perennial dies.
	* function.c (used_types_insert): New.
	* function.h (struct function): Add used_types_hash field.
	(used_types_insert): Add prototype.
	* Makefile.in (FUNCTION_H): Depend on HASHTAB_H.
	* c-parser.c (c_parser_cast_expression): Save casted types in used
	types hash table.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@112845 138bc75d-0d04-0410-961f-82ee72b054a4

8 files changed, 99 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 05581772ec2..209b378d34d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,18 @@
+2006-04-10  Aldy Hernandez  <aldyh@redhat.com>
+
+	PR/21391
+	* dwarf2out.c (struct die_struct): Add die_perennial_p field.
+	(premark_used_types_helper): New.
+	(premark_used_types): New.
+	(gen_subprogram_die): Call premark_used_types.
+	(prune_unused_types_walk): Do not prune perennial dies.
+	* function.c (used_types_insert): New.
+	* function.h (struct function): Add used_types_hash field.
+	(used_types_insert): Add prototype.
+	* Makefile.in (FUNCTION_H): Depend on HASHTAB_H.
+	* c-parser.c (c_parser_cast_expression): Save casted types in used
+	types hash table.
+
 2006-04-11  Mark Mitchell  <mark@codesourcery.com>
 
 	PR target/26459
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 25559e4ab33..d29fcaa961d 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -751,7 +751,7 @@ RECOG_H = recog.h
 ALIAS_H = alias.h
 EMIT_RTL_H = emit-rtl.h
 FLAGS_H = flags.h options.h
-FUNCTION_H = function.h $(TREE_H)
+FUNCTION_H = function.h $(TREE_H) $(HASHTAB_H)
 EXPR_H = expr.h insn-config.h $(FUNCTION_H) $(RTL_H) $(FLAGS_H) $(TREE_H) $(MACHMODE_H) $(EMIT_RTL_H)
 OPTABS_H = optabs.h insn-codes.h
 REGS_H = regs.h varray.h $(MACHMODE_H) $(OBSTACK_H) $(BASIC_BLOCK_H) $(FUNCTION_H)
diff --git a/gcc/c-parser.c b/gcc/c-parser.c
index b5722738ac9..0c90fa84bd8 100644
--- a/gcc/c-parser.c
+++ b/gcc/c-parser.c
@@ -4660,6 +4660,11 @@ c_parser_cast_expression (c_parser *parser, struct c_expr *after)
 	  ret.original_code = ERROR_MARK;
 	  return ret;
 	}
+
+      /* Save casted types in the function's used types hash table.  */
+      if (debug_info_level > DINFO_LEVEL_NONE)
+	used_types_insert (type_name->specs->type, cfun);
+
       if (c_parser_next_token_is (parser, CPP_OPEN_BRACE))
 	return c_parser_postfix_expression_after_paren_type (parser,
 							     type_name);
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 3a02acf725e..f7de3d7cfde 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -354,6 +354,7 @@ static void dwarf2out_stack_adjust (rtx, bool);
 static void flush_queued_reg_saves (void);
 static bool clobbers_queued_reg_save (rtx);
 static void dwarf2out_frame_debug_expr (rtx, const char *);
+static void premark_used_types (void);
 
 /* Support for complex CFA locations.  */
 static void output_cfa_loc (dw_cfi_ref);
@@ -3697,6 +3698,8 @@ typedef struct die_struct GTY(())
   dw_offset die_offset;
   unsigned long die_abbrev;
   int die_mark;
+  /* Die is used and must not be pruned as unused.  */
+  int die_perennial_p;
   unsigned int decl_id;
 }
 die_node;
@@ -11511,6 +11514,32 @@ dwarf2out_abstract_function (tree decl)
   current_function_decl = save_fn;
 }
 
+/* Helper function of premark_used_types() which gets called through
+   htab_traverse_resize().
+
+   Marks the DIE of a given type in *SLOT as perennial, so it never gets
+   marked as unused by prune_unused_types.  */
+static int
+premark_used_types_helper (void **slot, void *data ATTRIBUTE_UNUSED)
+{
+  tree type;
+  dw_die_ref die;
+
+  type = *slot;
+  die = lookup_type_die (type);
+  if (die != NULL)
+    die->die_perennial_p = 1;
+  return 1;
+}
+
+/* Mark all members of used_types_hash as perennial.  */
+static void
+premark_used_types (void)
+{
+  if (cfun && cfun->used_types_hash)
+    htab_traverse (cfun->used_types_hash, premark_used_types_helper, NULL);
+}
+
 /* Generate a DIE to represent a declared function (either file-scope or
    block-local).  */
 
@@ -11526,6 +11555,8 @@ gen_subprogram_die (tree decl, dw_die_ref context_die)
   int declaration = (current_function_decl != decl
 		     || class_or_namespace_scope_p (context_die));
 
+  premark_used_types();
+
   /* It is possible to have both DECL_ABSTRACT and DECLARATION be true if we
      started to generate the abstract instance of an inline, decided to output
      its containing class, and proceeded to emit the declaration of the inline
@@ -13965,6 +13996,9 @@ prune_unused_types_walk (dw_die_ref die)
   case DW_TAG_subrange_type:
   case DW_TAG_ptr_to_member_type:
   case DW_TAG_file_type:
+    if (die->die_perennial_p)
+      break;
+
     /* It's a type node --- don't mark it.  */
     return;
 
diff --git a/gcc/function.c b/gcc/function.c
index fd5eeb983fe..ecdf28232b5 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -5587,6 +5587,23 @@ rest_of_handle_check_leaf_regs (void)
   return 0;
 }
 
+/* Insert a type into the used types hash table.  */
+void
+used_types_insert (tree t, struct function *func)
+{
+  if (t != NULL && func != NULL)
+    {
+      void **slot;
+
+      if (func->used_types_hash == NULL)
+	func->used_types_hash = htab_create_ggc (37, htab_hash_pointer,
+					     htab_eq_pointer, NULL);
+      slot = htab_find_slot (func->used_types_hash, t, INSERT);
+      if (*slot == NULL)
+	*slot = t;
+    }
+}
+
 struct tree_opt_pass pass_leaf_regs =
 {
   NULL,                                 /* name */
diff --git a/gcc/function.h b/gcc/function.h
index 4a60eb2d705..282e04c1047 100644
--- a/gcc/function.h
+++ b/gcc/function.h
@@ -23,6 +23,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
 #define GCC_FUNCTION_H
 
 #include "tree.h"
+#include "hashtab.h"
 
 struct var_refs_queue GTY(())
 {
@@ -312,6 +313,9 @@ struct function GTY(())
   /* Language-specific code can use this to store whatever it likes.  */
   struct language_function * language;
 
+  /* Used types hash table.  */
+  htab_t GTY ((param_is (union tree_node))) used_types_hash;
+
   /* For reorg.  */
 
   /* If some insns can be deferred to the delay slots of the epilogue, the
@@ -566,4 +570,6 @@ extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode,
 				     tree, bool);
 
+extern void used_types_insert (tree, struct function *);
+
 #endif  /* GCC_FUNCTION_H */
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9f16bfec7e4..237a690b657 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2006-04-10  Aldy Hernandez  <aldyh@redhat.com>
+
+	PR/21391
+	* gcc.dg/20060410.c: New.
+
 2006-04-10  Matthias Klose  <doko@debian.org>
 
 	* testsuite/lib/gcc-defs.exp (gcc-set-multilib-library-path):
diff --git a/gcc/testsuite/gcc.dg/20060410.c b/gcc/testsuite/gcc.dg/20060410.c
new file mode 100644
index 00000000000..88253bb43f3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/20060410.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-g" } */
+
+/* Make sure we didn't eliminate foo because we thought it was unused.  */
+
+struct foo 
+{
+    int i;
+};
+
+int bar (void)
+{
+    return ((struct foo *)0x1234)->i;
+}
+
+/* { dg-final { scan-assembler "foo" } } */