[patch] Fix PR lto/48148

[Eric Botcazou <ebotcazou at adacore dot com>]

Hi,

this is the assembler error during an LTO bootstrap:

cc1.ltrans8.s: Assembler messages:
cc1.ltrans8.s:249143: Error: symbol `.Ldebug_info0' is already defined

In the assembly file:

.Letext0:
	.file 93 "/home/eric/svn/gcc/gcc/c-parser.c"
	.section	.debug_info,"",@progbits
.Ldebug_info0:
[...]
	.file 225 "/usr/include/mpc.h"
	.file 226 "/usr/include/mpfr.h"
.Ldebug_info0:


output_comp_unit is passed a completely bogus DIE:

DIE   11: DW_TAG_enumeration_type (0x7ffff2024a50)
  abbrev id: 1 offset: 11 mark: 1
  DW_AT_name: "prec"
  DW_AT_byte_size: 4
  DW_AT_decl_file: "/home/eric/svn/gcc/gcc/c-parser.c" (93)
  DW_AT_decl_line: 5459

created by the call to resolve_addr at line 23613 of dwarf2out.c:

  limbo_die_list = NULL;

  resolve_addr (comp_unit_die ());


#20 0x00000000005941a6 in gen_formal_parameter_die (node=0x7ffff5dc6000,
    origin=0x0, emit_name_p=1 '\001', context_die=0x7ffff4b28780)
    at /home/eric/svn/gcc/gcc/dwarf2out.c:18682
#21 0x0000000000594303 in gen_formal_types_die (
    function_or_method_type=0x7ffff5dcba80, context_die=0x7ffff4b28780)
    at /home/eric/svn/gcc/gcc/dwarf2out.c:18776
#22 0x0000000000592187 in gen_subprogram_die (decl=0x7ffff5dce300,
    context_die=0x7ffff2c13f00) at /home/eric/svn/gcc/gcc/dwarf2out.c:19388
#23 0x000000000059b632 in force_decl_die (decl=0x7ffff5dce300)
    at /home/eric/svn/gcc/gcc/dwarf2out.c:21025
#24 0x000000000059bb25 in resolve_addr (die=0x7ffff3d747d0)
    at /home/eric/svn/gcc/gcc/dwarf2out.c:23115
23115                   force_decl_die (tdecl);
(gdb) p debug_dwarf_die(die)
DIE    0: DW_TAG_GNU_call_site (0x7ffff3d747d0)
  abbrev id: 0 offset: 0 mark: 0
  DW_AT_low_pc: label: *.LVL13657
  DW_AT_abstract_origin: address

	if (die->die_tag == DW_TAG_GNU_call_site
	    && a->dw_attr == DW_AT_abstract_origin)
	  {
	    tree tdecl = SYMBOL_REF_DECL (a->dw_attr_val.v.val_addr);
	    dw_die_ref tdie = lookup_decl_die (tdecl);
	    if (tdie == NULL
		&& DECL_EXTERNAL (tdecl)
		&& DECL_ABSTRACT_ORIGIN (tdecl) == NULL_TREE)
	      {
		force_decl_die (tdecl);


The DW_TAG_enumeration_type DIE is for an unrelated type of c-parser.c:

static struct c_expr
c_parser_binary_expression (c_parser *parser, struct c_expr *after)
{
  enum prec {
    PREC_NONE,
    PREC_LOGOR,
    PREC_LOGAND,
    PREC_BITOR,
    PREC_BITXOR,
    PREC_BITAND,
    PREC_EQ,
    PREC_REL,
    PREC_SHIFT,
    PREC_ADD,
    PREC_MULT,
    NUM_PRECS
  };

which happens to be merged with a type at top-level in cpplib.h:

/* C language kind, used when calling cpp_create_reader.  */
enum c_lang {CLK_GNUC89 = 0, CLK_GNUC99, CLK_GNUC1X,
	     CLK_STDC89, CLK_STDC94, CLK_STDC99, CLK_STDC1X,
	     CLK_GNUCXX, CLK_CXX98, CLK_GNUCXX0X, CLK_CXX0X, CLK_ASM};

so the LANG field of:

struct cpp_options
{
  /* Characters between tab stops.  */
  unsigned int tabstop;

  /* The language we're preprocessing.  */
  enum c_lang lang;

gets enum prec as type and things go downhill from there.


I don't think the two enum types should be merged: fields of structures are 
merged only if they have the same identifier, this should apply here as well.
Hence the attached patch.  LTO bootstrapped on x86_64-suse-linux, OK for the 
mainline?


2011-04-18  Eric Botcazou  <ebotcazou@adacore.com>

	PR lto/48148
	* gimple.c (gimple_types_compatible_p_1) <ENUMERAL_TYPE>: Do not
	merge the types if they have different enumeration identifiers.


-- 
Eric Botcazou

Index: gimple.c
===================================================================
--- gimple.c	(revision 172617)
+++ gimple.c	(working copy)
@@ -3731,6 +3731,9 @@ gimple_types_compatible_p_1 (tree t1, tr
 
 	    if (tree_int_cst_equal (c1, c2) != 1)
 	      goto different_types;
+
+	    if (mode == GTC_MERGE && TREE_PURPOSE (v1) != TREE_PURPOSE (v2))
+	      goto different_types;
 	  }
 
 	/* If one enumeration has more values than the other, they