[LTO][PATCH] Generate and use the .debug_str section when compiling with LTO

["William Maddox" <maddox at google dot com>]

This patch modifies the LTO reader to read the .debug_str section,
if present, and to resolve DW_FORM_strp attributes.  It also removes
the workaround in dwarf2out.c for the previous inability of LTO to grok
string table references.

gcc/
       * dwarf2out.c (AT_string_form): Remove code to suppress
       the use of the DWARF string table.

gcc/lto
       * lto.c (lto_str_fd_init): New function.
       (lto_str_fd_close): New function.
       (lto_file_init): Call lto_str_fd_init.
       (lto_file_close): Call lto_str_fd_close.
       (lto_str_read): New function. Read debug string table.
       (lto_str_lookup): New function. Get string for debug
       string table offset.
       (lto_read_form): Recognize DW_FORM_strp.
       (lto_file_read): Invoke lto_str_read.

       * lto-elf.c (lto_elf_file_open): Read raw section data
       for the .debug_str section, if present.

       * lto.h (struct lto_str_fd_struct): New struct.
       (struct lto_file_struct): Added new field DEBUG_STR
       to hold the file descriptor for the debug string table.

Attachment: lto-string-table-patch.txt
Description: Text document