On Mon, Sep 21, 2015 at 5:41 PM, David Edelsohn <[email protected]> wrote:
> Appended is a patch to support DWARF on AIX and works with GDB and AIX
> assembler. The AIX assembler prepends the CU length to the section
> and does not want the compiler to provide it, so I need to disable
> those parts of dwarf2out.c. I know it's ugly, but, on the upside,
> this eventually allows GCC to deprecate Stabs, which I think is worth
> the pain.
>
> I discovered that -g3 emits the debug_macros section, which AIX also
> does not like, so I disable that section as well. As I mentioned in
> v2, I moved the calculation of aranges_length to its one use in the
> output function instead of calculating it early to avoid an unused
> function argument.
>
> I also switched to XCOFF_DEBUGGING_INFO as the macro to test in
> dwarf2out.c. I think a target hook or testing that DWARF section
> names have not been overridden to NULL is overkill. Suggestions
> welcome, but any solution that disables arbitrary portions of
> dwarf2out.c is going to be ugly. I doubt that any other system,
> especially ones based on ELF file format, would ever do this.
Using an existing macro works for me - but as we are working towards
eliminating conditional compilation can you try using
if (!XCOFF_DEBUGGING_INFO)
? If the macro is not always defined devise a new one defined from
XCOFF_DEBUGGING_INFO.
Richard.
> With a few tweaks to the testsuite, this passes GCC dwarf2 tests.
>
> Thanks, David
>
> * dwarf2out.c (size_of_pubnames): Don't define on AIX.
> (size_of_aranges): Don't define on AIX.
> (output_compilation_unit_header): Don't output length on AIX.
> (output_pubnames): Don't output length on AIX.
> (output_aranges): Delete argument. Compute length locally. Don't
> output length on AIX.
> (output_line_info): Don't output length on AIX.
> (dwarf2out_finish): Don't output location lists on AIX.
> Don't compute aranges_length. Don't output macros section.
> * config/rs6000/rs6000.c (rs6000_xcoff_debug_unwind_info):
> New.
> (rs6000_xcoff_asm_named_section): Emit .dwsect pseudo-op
> for SECTION_DEBUG.
> (rs6000_xcoff_declare_function_name): Emit different
> .function pseudo-op when DWARF2_DEBUG.
> * config/rs6000/xcoff.h (TARGET_DEBUG_UNWIND_INFO):
> Redefine.
> * config/rs6000/aix71.h (DWARF2_DEBUGGING_INFO): Define.
> (PREFERRED_DEBUGGING_TYPE): Define.
> (DEBUG_INFO_SECTION): Define.
> (DEBUG_ABBREV_SECTION): Define.
> (DEBUG_ARANGES_SECTION): Define.
> (DEBUG_LINE_SECTION): Define.
> (DEBUG_PUBNAMES_SECTION): Define.
> (DEBUG_PUBTYPES_SECTION): Define.
> (DEBUG_STR_SECTION): Define.
> (DEBUG_RANGES_SECTION): Define.
>
> Index: dwarf2out.c
> ===================================================================
> --- dwarf2out.c (revision 227959)
> +++ dwarf2out.c (working copy)
> @@ -3185,8 +3185,10 @@ static void calc_base_type_die_sizes (void);
> static void mark_dies (dw_die_ref);
> static void unmark_dies (dw_die_ref);
> static void unmark_all_dies (dw_die_ref);
> +#ifndef XCOFF_DEBUGGING_INFO
> static unsigned long size_of_pubnames (vec<pubname_entry, va_gc> *);
> static unsigned long size_of_aranges (void);
> +#endif
> static enum dwarf_form value_format (dw_attr_node *);
> static void output_value_format (dw_attr_node *);
> static void output_abbrev_section (void);
> @@ -3202,7 +3204,7 @@ static void add_enumerator_pubname (const char *,
> static void add_pubname_string (const char *, dw_die_ref);
> static void add_pubtype (tree, dw_die_ref);
> static void output_pubnames (vec<pubname_entry, va_gc> *);
> -static void output_aranges (unsigned long);
> +static void output_aranges (void);
> static unsigned int add_ranges_num (int);
> static unsigned int add_ranges (const_tree);
> static void add_ranges_by_labels (dw_die_ref, const char *, const char *,
> @@ -8387,6 +8389,7 @@ include_pubname_in_output (vec<pubname_entry, va_g
> || !flag_eliminate_unused_debug_types);
> }
>
> +#ifndef XCOFF_DEBUGGING_INFO
> /* Return the size of the .debug_pubnames or .debug_pubtypes table
> generated for the compilation unit. */
>
> @@ -8441,6 +8444,7 @@ size_of_aranges (void)
> size += 2 * DWARF2_ADDR_SIZE;
> return size;
> }
> +#endif
> ^L
> /* Select the encoding of an attribute value. */
>
> @@ -9198,12 +9202,14 @@ output_compilation_unit_header (void)
> DWARFv5 draft DIE tags in DWARFv4 format. */
> int ver = dwarf_version < 5 ? dwarf_version : 4;
>
> +#ifndef XCOFF_DEBUGGING_INFO
> if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
> dw2_asm_output_data (4, 0xffffffff,
> "Initial length escape value indicating 64-bit DWARF extension");
> dw2_asm_output_data (DWARF_OFFSET_SIZE,
> next_die_offset - DWARF_INITIAL_LENGTH_SIZE,
> "Length of Compilation Unit Info");
> +#endif
> dw2_asm_output_data (2, ver, "DWARF version number");
> dw2_asm_output_offset (DWARF_OFFSET_SIZE, abbrev_section_label,
> debug_abbrev_section,
> @@ -9630,13 +9636,16 @@ static void
> output_pubnames (vec<pubname_entry, va_gc> *names)
> {
> unsigned i;
> - unsigned long pubnames_length = size_of_pubnames (names);
> pubname_entry *pub;
>
> +#ifndef XCOFF_DEBUGGING_INFO
> + unsigned long pubnames_length = size_of_pubnames (names);
> +
> if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
> dw2_asm_output_data (4, 0xffffffff,
> "Initial length escape value indicating 64-bit DWARF extension");
> dw2_asm_output_data (DWARF_OFFSET_SIZE, pubnames_length, "Pub Info
> Length");
> +#endif
>
> /* Version number for pubnames/pubtypes is independent of dwarf version.
> */
> dw2_asm_output_data (2, 2, "DWARF Version");
> @@ -9706,15 +9715,19 @@ output_pubtables (void)
> text section generated for this compilation unit. */
>
> static void
> -output_aranges (unsigned long aranges_length)
> +output_aranges (void)
> {
> unsigned i;
>
> - if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
> +#ifndef XCOFF_DEBUGGING_INFO
> + unsigned long aranges_length = size_of_aranges ();
> +
> +if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
> dw2_asm_output_data (4, 0xffffffff,
> "Initial length escape value indicating 64-bit DWARF extension");
> dw2_asm_output_data (DWARF_OFFSET_SIZE, aranges_length,
> "Length of Address Ranges Info");
> +#endif
> /* Version number for aranges is still 2, even up to DWARF5. */
> dw2_asm_output_data (2, 2, "DWARF Version");
> if (dwarf_split_debug_info)
> @@ -10398,11 +10411,13 @@ output_line_info (bool prologue_only)
> ASM_GENERATE_INTERNAL_LABEL (p1, LN_PROLOG_AS_LABEL, 0);
> ASM_GENERATE_INTERNAL_LABEL (p2, LN_PROLOG_END_LABEL, 0);
>
> +#ifndef XCOFF_DEBUGGING_INFO
> if (DWARF_INITIAL_LENGTH_SIZE - DWARF_OFFSET_SIZE == 4)
> dw2_asm_output_data (4, 0xffffffff,
> "Initial length escape value indicating 64-bit DWARF extension");
> dw2_asm_output_delta (DWARF_OFFSET_SIZE, l2, l1,
> "Length of Source Line Info");
> +#endif
> ASM_OUTPUT_LABEL (asm_out_file, l1);
>
> dw2_asm_output_data (2, ver, "DWARF Version");
> @@ -25486,6 +25501,7 @@ dwarf2out_finish (const char *filename)
> output_abbrev_section ();
> }
>
> +#ifndef XCOFF_DEBUGGING_INFO
> /* Output location list section if necessary. */
> if (have_location_lists)
> {
> @@ -25494,6 +25510,7 @@ dwarf2out_finish (const char *filename)
> ASM_OUTPUT_LABEL (asm_out_file, loc_section_label);
> output_location_lists (comp_unit_die ());
> }
> +#endif
>
> output_pubtables ();
>
> @@ -25504,10 +25521,8 @@ dwarf2out_finish (const char *filename)
> generate a table that would have contained data. */
> if (info_section_emitted)
> {
> - unsigned long aranges_length = size_of_aranges ();
> -
> switch_to_section (debug_aranges_section);
> - output_aranges (aranges_length);
> + output_aranges ();
> }
>
> /* Output ranges section if necessary. */
> @@ -25518,6 +25533,7 @@ dwarf2out_finish (const char *filename)
> output_ranges ();
> }
>
> +#ifndef XCOFF_DEBUGGING_INFO
> /* Have to end the macro section. */
> if (have_macinfo)
> {
> @@ -25526,6 +25542,7 @@ dwarf2out_finish (const char *filename)
> output_macinfo ();
> dw2_asm_output_data (1, 0, "End compilation unit");
> }
> +#endif
>
> /* Output the source line correspondence table. We must do this
> even if there is no line information. Otherwise, on an empty
> Index: config/rs6000/rs6000.c
> ===================================================================
> --- config/rs6000/rs6000.c (revision 227937)
> +++ config/rs6000/rs6000.c (working copy)
> @@ -30684,6 +30684,12 @@
> #endif
>
> #if TARGET_XCOFF
> +static enum unwind_info_type
> +rs6000_xcoff_debug_unwind_info (void)
> +{
> + return UI_NONE;
> +}
> +
> static void
> rs6000_xcoff_asm_output_anchor (rtx symbol)
> {
> @@ -30805,6 +30811,11 @@
> int smclass;
> static const char * const suffix[4] = { "PR", "RO", "RW", "TL" };
>
> + if (flags & SECTION_DEBUG)
> + {
> + fprintf (asm_out_file, "\t.dwsect %s\n", name);
> + return;
> + }
> if (flags & SECTION_CODE)
> smclass = 0;
> else if (flags & SECTION_TLS)
> @@ -31140,8 +31151,16 @@
> fputs (":\n", file);
> data.function_descriptor = true;
> symtab_node::get (decl)->call_for_symbol_and_aliases
> (rs6000_declare_alias, &
> data, true);
> - if (write_symbols != NO_DEBUG && !DECL_IGNORED_P (decl))
> - xcoffout_declare_function (file, decl, buffer);
> + if (!DECL_IGNORED_P (decl))
> + {
> + if (write_symbols == DBX_DEBUG || write_symbols == XCOFF_DEBUG)
> + xcoffout_declare_function (file, decl, buffer);
> + else if (write_symbols == DWARF2_DEBUG)
> + {
> + name = (*targetm.strip_name_encoding) (name);
> + fprintf (file, "\t.function .%s,.%s,2,0\n", name, name);
> + }
> + }
> return;
> }
>
> Index: config/rs6000/xcoff.h
> ===================================================================
> --- config/rs6000/xcoff.h (revision 227937)
> +++ config/rs6000/xcoff.h (working copy)
> @@ -86,6 +86,8 @@
> || (SCALAR_FLOAT_MODE_P (GET_MODE (X)) \
> && ! TARGET_NO_FP_IN_TOC)))))
>
> +#undef TARGET_DEBUG_UNWIND_INFO
> +#define TARGET_DEBUG_UNWIND_INFO rs6000_xcoff_debug_unwind_info
> #define TARGET_ASM_OUTPUT_ANCHOR rs6000_xcoff_asm_output_anchor
> #define TARGET_ASM_GLOBALIZE_LABEL rs6000_xcoff_asm_globalize_label
> #define TARGET_ASM_INIT_SECTIONS rs6000_xcoff_asm_init_sections
> Index: config/rs6000/aix71.h
> ===================================================================
> +/* AIX 7.1 supports DWARF debugging, but XCOFF remains the default. */
> +#define DWARF2_DEBUGGING_INFO 1
> +#define PREFERRED_DEBUGGING_TYPE XCOFF_DEBUG
> +#define DEBUG_INFO_SECTION "0x10000"
> +#define DEBUG_ABBREV_SECTION "0x60000"
> +#define DEBUG_ARANGES_SECTION "0x50000"
> +#define DEBUG_LINE_SECTION "0x20000"
> +#define DEBUG_PUBNAMES_SECTION "0x30000"
> +#define DEBUG_PUBTYPES_SECTION "0x40000"
> +#define DEBUG_STR_SECTION "0x70000"
> +#define DEBUG_RANGES_SECTION "0x80000"
