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authorDavid Blaikie <dblaikie@gmail.com>2017-07-06 11:17:52 -0700
committerDavid Blaikie <dblaikie@gmail.com>2017-07-06 11:59:39 -0700
commit33c5cd75874c36374c0966c59feeaf6f17512499 (patch)
tree0606b4459c84ace78bd44375949527e38079b470
parenta0b7b105236d5bc65e8d3a35f1b4f34bcc5e3705 (diff)
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Fission support for multiple CUs per DWO file
In some cases a compiler may produce a single object file (& thus single DWO file) representing multiple source files. The most common example of this is in whole program optimization (such as LLVM's LTO). Fission may still be a beneficial feature to use here - to avoid the need to read/link the debug info with system libraries and the like. This change adds basic support for multiple CUs in a single DWO file to support LLVM's output in this situation. There is still outstanding work to design and implement a solution for cross-CU references (usually using DW_FORM_ref_addr) in this scenario. For now LLVM works around this by duplicating DIEs rather than making cross-CU references in DWO files. This degrades debugger behavior/quality especially for file-local entities. 2017-07-06 David Blaikie <dblaikie@gmail.com> * dwarf2read.c (struct dwo_file): Use a htab of dwo_unit* (rather than a singular dwo_unit*) to support multiple CUs in the same way that multiple TUs are supported. (create_cus_hash_table): Replace create_dwo_cu with a function for parsing multiple CUs from a DWO file. (open_and_init_dwo_file): Use create_cus_hash_table rather than create_dwo_cu. (lookup_dwo_cutu): Lookup CU in the hash table in the dwo_file with htab_find, rather than comparing the signature to a singleton CU in the dwo_file. 2017-07-06 David Blaikie <dblaikie@gmail.com> * gdb.dwarf2/fission-multi-cu.S: Test containing multiple CUs in a DWO, built from fissiont-multi-cu{1,2}.c. * gdb.dwarf2/fission-multi-cu.exp: Test similar to fission-base.exp, except putting 'main' and 'func' in separate CUs in the same DWO file. * gdb.dwarf2/fission-multi-cu1.c: First CU for the multi-CU-single-DWO test. * gdb.dwarf2/fission-multi-cu2.c: Second CU in the multi-CU-single-DWO test.
-rw-r--r--gdb/ChangeLog13
-rw-r--r--gdb/dwarf2read.c100
-rw-r--r--gdb/testsuite/ChangeLog11
-rw-r--r--gdb/testsuite/gdb.dwarf2/fission-multi-cu.S374
-rw-r--r--gdb/testsuite/gdb.dwarf2/fission-multi-cu.exp67
-rw-r--r--gdb/testsuite/gdb.dwarf2/fission-multi-cu1.c22
-rw-r--r--gdb/testsuite/gdb.dwarf2/fission-multi-cu2.c24
7 files changed, 564 insertions, 47 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 7908142..a474077 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,16 @@
+2017-07-06 David Blaikie <dblaikie@gmail.com>
+
+ * dwarf2read.c (struct dwo_file): Use a htab of dwo_unit* (rather than
+ a singular dwo_unit*) to support multiple CUs in the same way that
+ multiple TUs are supported.
+ (create_cus_hash_table): Replace create_dwo_cu with a function for
+ parsing multiple CUs from a DWO file.
+ (open_and_init_dwo_file): Use create_cus_hash_table rather than
+ create_dwo_cu.
+ (lookup_dwo_cutu): Lookup CU in the hash table in the dwo_file with
+ htab_find, rather than comparing the signature to a singleton CU in
+ the dwo_file.
+
2017-07-06 Pedro Alves <palves@redhat.com>
* python/py-unwind.c (pyuw_dealloc_cache): Fix for loop condition.
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 2f70bd2..0fdcd42 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -855,12 +855,11 @@ struct dwo_file
sections (for lack of a better name). */
struct dwo_sections sections;
- /* The CU in the file.
- We only support one because having more than one requires hacking the
- dwo_name of each to match, which is highly unlikely to happen.
- Doing this means all TUs can share comp_dir: We also assume that
- DW_AT_comp_dir across all TUs in a DWO file will be identical. */
- struct dwo_unit *cu;
+ /* The CUs in the file.
+ Each element is a struct dwo_unit. Multiple CUs per DWO are supported as
+ an extension to handle LLVM's Link Time Optimization output (where
+ multiple source files may be compiled into a single object/dwo pair). */
+ htab_t cus;
/* Table of TUs in the file.
Each element is a struct dwo_unit. */
@@ -9700,72 +9699,75 @@ create_dwo_cu_reader (const struct die_reader_specs *reader,
hex_string (dwo_unit->signature));
}
-/* Create the dwo_unit for the lone CU in DWO_FILE.
+/* Create the dwo_units for the CUs in a DWO_FILE.
Note: This function processes DWO files only, not DWP files. */
-static struct dwo_unit *
-create_dwo_cu (struct dwo_file *dwo_file)
+static void
+create_cus_hash_table (struct dwo_file &dwo_file, dwarf2_section_info &section,
+ htab_t &cus_htab)
{
struct objfile *objfile = dwarf2_per_objfile->objfile;
- struct dwarf2_section_info *section = &dwo_file->sections.info;
+ const struct dwarf2_section_info *abbrev_section = &dwo_file.sections.abbrev;
const gdb_byte *info_ptr, *end_ptr;
- struct create_dwo_cu_data create_dwo_cu_data;
- struct dwo_unit *dwo_unit;
- dwarf2_read_section (objfile, section);
- info_ptr = section->buffer;
+ dwarf2_read_section (objfile, &section);
+ info_ptr = section.buffer;
if (info_ptr == NULL)
- return NULL;
+ return;
if (dwarf_read_debug)
{
fprintf_unfiltered (gdb_stdlog, "Reading %s for %s:\n",
- get_section_name (section),
- get_section_file_name (section));
+ get_section_name (&section),
+ get_section_file_name (&section));
}
- create_dwo_cu_data.dwo_file = dwo_file;
- dwo_unit = NULL;
-
- end_ptr = info_ptr + section->size;
+ end_ptr = info_ptr + section.size;
while (info_ptr < end_ptr)
{
struct dwarf2_per_cu_data per_cu;
+ struct create_dwo_cu_data create_dwo_cu_data;
+ struct dwo_unit *dwo_unit;
+ void **slot;
+ sect_offset sect_off = (sect_offset) (info_ptr - section.buffer);
memset (&create_dwo_cu_data.dwo_unit, 0,
sizeof (create_dwo_cu_data.dwo_unit));
memset (&per_cu, 0, sizeof (per_cu));
per_cu.objfile = objfile;
per_cu.is_debug_types = 0;
- per_cu.sect_off = sect_offset (info_ptr - section->buffer);
- per_cu.section = section;
+ per_cu.sect_off = sect_offset (info_ptr - section.buffer);
+ per_cu.section = &section;
+
+ init_cutu_and_read_dies_no_follow (
+ &per_cu, &dwo_file, create_dwo_cu_reader, &create_dwo_cu_data);
+ info_ptr += per_cu.length;
+
+ // If the unit could not be parsed, skip it.
+ if (create_dwo_cu_data.dwo_unit.dwo_file == NULL)
+ continue;
- init_cutu_and_read_dies_no_follow (&per_cu, dwo_file,
- create_dwo_cu_reader,
- &create_dwo_cu_data);
+ if (cus_htab == NULL)
+ cus_htab = allocate_dwo_unit_table (objfile);
- if (create_dwo_cu_data.dwo_unit.dwo_file != NULL)
+ dwo_unit = OBSTACK_ZALLOC (&objfile->objfile_obstack, struct dwo_unit);
+ *dwo_unit = create_dwo_cu_data.dwo_unit;
+ slot = htab_find_slot (cus_htab, dwo_unit, INSERT);
+ gdb_assert (slot != NULL);
+ if (*slot != NULL)
{
- /* If we've already found one, complain. We only support one
- because having more than one requires hacking the dwo_name of
- each to match, which is highly unlikely to happen. */
- if (dwo_unit != NULL)
- {
- complaint (&symfile_complaints,
- _("Multiple CUs in DWO file %s [in module %s]"),
- dwo_file->dwo_name, objfile_name (objfile));
- break;
- }
+ const struct dwo_unit *dup_cu = (const struct dwo_unit *)*slot;
+ sect_offset dup_sect_off = dup_cu->sect_off;
- dwo_unit = OBSTACK_ZALLOC (&objfile->objfile_obstack, struct dwo_unit);
- *dwo_unit = create_dwo_cu_data.dwo_unit;
+ complaint (&symfile_complaints,
+ _("debug cu entry at offset 0x%x is duplicate to"
+ " the entry at offset 0x%x, signature %s"),
+ to_underlying (sect_off), to_underlying (dup_sect_off),
+ hex_string (dwo_unit->signature));
}
-
- info_ptr += per_cu.length;
+ *slot = (void *)dwo_unit;
}
-
- return dwo_unit;
}
/* DWP file .debug_{cu,tu}_index section format:
@@ -10770,7 +10772,7 @@ open_and_init_dwo_file (struct dwarf2_per_cu_data *per_cu,
bfd_map_over_sections (dwo_file->dbfd, dwarf2_locate_dwo_sections,
&dwo_file->sections);
- dwo_file->cu = create_dwo_cu (dwo_file);
+ create_cus_hash_table (*dwo_file, dwo_file->sections.info, dwo_file->cus);
create_debug_types_hash_table (dwo_file, dwo_file->sections.types,
dwo_file->tus);
@@ -11137,10 +11139,14 @@ lookup_dwo_cutu (struct dwarf2_per_cu_data *this_unit,
dwo_cutu
= (struct dwo_unit *) htab_find (dwo_file->tus, &find_dwo_cutu);
}
- else if (!is_debug_types && dwo_file->cu)
+ else if (!is_debug_types && dwo_file->cus)
{
- if (signature == dwo_file->cu->signature)
- dwo_cutu = dwo_file->cu;
+ struct dwo_unit find_dwo_cutu;
+
+ memset (&find_dwo_cutu, 0, sizeof (find_dwo_cutu));
+ find_dwo_cutu.signature = signature;
+ dwo_cutu = (struct dwo_unit *)htab_find (dwo_file->cus,
+ &find_dwo_cutu);
}
if (dwo_cutu != NULL)
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index d6a7252..8f28f44 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,14 @@
+2017-07-06 David Blaikie <dblaikie@gmail.com>
+
+ * gdb.dwarf2/fission-multi-cu.S: Test containing multiple CUs in a DWO,
+ built from fissiont-multi-cu{1,2}.c.
+ * gdb.dwarf2/fission-multi-cu.exp: Test similar to fission-base.exp,
+ except putting 'main' and 'func' in separate CUs in the same DWO file.
+ * gdb.dwarf2/fission-multi-cu1.c: First CU for the multi-CU-single-DWO
+ test.
+ * gdb.dwarf2/fission-multi-cu2.c: Second CU in the multi-CU-single-DWO
+ test.
+
2017-07-06 Pedro Alves <palves@redhat.com>
* gdb.python/py-unwind.exp: Test flushregs.
diff --git a/gdb/testsuite/gdb.dwarf2/fission-multi-cu.S b/gdb/testsuite/gdb.dwarf2/fission-multi-cu.S
new file mode 100644
index 0000000..d09a7e5
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/fission-multi-cu.S
@@ -0,0 +1,374 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2012-2017 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+ This file was created by doing:
+
+ clang fission-multi-cu*.c -g -fno-split-dwarf-inlining -emit-llvm -S -c
+ llvm-link fission-multi-cu*.ll -S -o fission-multi-cu.ll
+ clang-tot fission-multi-cu.ll -gsplit-dwarf -S
+
+ and then massaging the output.
+*/
+ .text
+ .file "llvm-link"
+ .globl func
+ .p2align 4, 0x90
+ .type func,@function
+func: # @func
+.Lfunc_begin0:
+ .file 1 "fission-multi-cu1.c"
+ .loc 1 20 0 # fission-multi-cu1.c:20:0
+ .cfi_startproc
+# BB#0: # %entry
+ pushq %rbp
+ .cfi_def_cfa_offset 16
+ .cfi_offset %rbp, -16
+ movq %rsp, %rbp
+ .cfi_def_cfa_register %rbp
+ movl %edi, -4(%rbp)
+ .loc 1 21 10 prologue_end # fission-multi-cu1.c:21:10
+ movl -4(%rbp), %edi
+ .loc 1 21 14 is_stmt 0 # fission-multi-cu1.c:21:14
+ addl $1, %edi
+ .loc 1 21 3 # fission-multi-cu1.c:21:3
+ movl %edi, %eax
+ popq %rbp
+ retq
+.Lfunc_end0:
+ .size func, .Lfunc_end0-func
+ .cfi_endproc
+
+ .globl main
+ .p2align 4, 0x90
+ .type main,@function
+main: # @main
+.Lfunc_begin1:
+ .file 2 "fission-multi-cu2.c"
+ .loc 2 23 0 is_stmt 1 # fission-multi-cu2.c:23:0
+ .cfi_startproc
+# BB#0: # %entry
+ pushq %rbp
+ .cfi_def_cfa_offset 16
+ .cfi_offset %rbp, -16
+ movq %rsp, %rbp
+ .cfi_def_cfa_register %rbp
+ movl $4294967295, %edi # imm = 0xFFFFFFFF
+ .loc 2 24 3 prologue_end # fission-multi-cu2.c:24:3
+ movb $0, %al
+ callq func
+ xorl %eax, %eax
+ .loc 2 25 1 # fission-multi-cu2.c:25:1
+ popq %rbp
+ retq
+.Lfunc_end1:
+ .size main, .Lfunc_end1-main
+ .cfi_endproc
+
+ .section .debug_str,"MS",@progbits,1
+.Lskel_string0:
+ .asciz "fission-multi-cu.dwo" # string offset=0
+.Lskel_string1:
+ .asciz "/tmp/src/gdb/testsuite" # string offset=21
+ .section .debug_loc.dwo,"",@progbits
+ .section .debug_abbrev,"",@progbits
+ .byte 1 # Abbreviation Code
+ .byte 17 # DW_TAG_compile_unit
+ .byte 0 # DW_CHILDREN_no
+ .byte 16 # DW_AT_stmt_list
+ .byte 23 # DW_FORM_sec_offset
+ .ascii "\260B" # DW_AT_GNU_dwo_name
+ .byte 14 # DW_FORM_strp
+ .byte 27 # DW_AT_comp_dir
+ .byte 14 # DW_FORM_strp
+ .ascii "\261B" # DW_AT_GNU_dwo_id
+ .byte 7 # DW_FORM_data8
+ .ascii "\263B" # DW_AT_GNU_addr_base
+ .byte 23 # DW_FORM_sec_offset
+ .byte 17 # DW_AT_low_pc
+ .byte 1 # DW_FORM_addr
+ .byte 18 # DW_AT_high_pc
+ .byte 6 # DW_FORM_data4
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 0 # EOM(3)
+ .section .debug_info,"",@progbits
+.Lcu_begin0:
+ .long 44 # Length of Unit
+ .short 4 # DWARF version number
+ .long .debug_abbrev # Offset Into Abbrev. Section
+ .byte 8 # Address Size (in bytes)
+ .byte 1 # Abbrev [1] 0xb:0x25 DW_TAG_compile_unit
+ .long .Lline_table_start0 # DW_AT_stmt_list
+ .long .Lskel_string0 # DW_AT_GNU_dwo_name
+ .long .Lskel_string1 # DW_AT_comp_dir
+ .quad 7615852067747431413 # DW_AT_GNU_dwo_id
+ .long .debug_addr # DW_AT_GNU_addr_base
+ .quad .Lfunc_begin0 # DW_AT_low_pc
+ .long .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+.Lcu_begin1:
+ .long 44 # Length of Unit
+ .short 4 # DWARF version number
+ .long .debug_abbrev # Offset Into Abbrev. Section
+ .byte 8 # Address Size (in bytes)
+ .byte 1 # Abbrev [1] 0xb:0x25 DW_TAG_compile_unit
+ .long .Lline_table_start0 # DW_AT_stmt_list
+ .long .Lskel_string0 # DW_AT_GNU_dwo_name
+ .long .Lskel_string1 # DW_AT_comp_dir
+ .quad 2037650261599692324 # DW_AT_GNU_dwo_id
+ .long .debug_addr # DW_AT_GNU_addr_base
+ .quad .Lfunc_begin1 # DW_AT_low_pc
+ .long .Lfunc_end1-.Lfunc_begin1 # DW_AT_high_pc
+ .section .debug_ranges,"",@progbits
+ .section .debug_macinfo,"",@progbits
+.Lcu_macro_begin1:
+.Lcu_macro_begin3:
+ .byte 0 # End Of Macro List Mark
+ .section .debug_str.dwo,"MS",@progbits,1
+.Linfo_string0:
+ .asciz "fission-multi-cu.dwo" # string offset=0
+.Linfo_string1:
+ .asciz "clang version 5.0.0 (trunk 302855) (llvm/trunk 302853)" # string offset=21
+.Linfo_string2:
+ .asciz "fission-multi-cu1.c" # string offset=76
+.Linfo_string3:
+ .asciz "fission-multi-cu2.c" # string offset=96
+.Linfo_string4:
+ .asciz "func" # string offset=116
+.Linfo_string5:
+ .asciz "int" # string offset=121
+.Linfo_string6:
+ .asciz "main" # string offset=125
+.Linfo_string7:
+ .asciz "arg" # string offset=130
+ .section .debug_str_offsets.dwo,"",@progbits
+ .long 0
+ .long 21
+ .long 76
+ .long 96
+ .long 116
+ .long 121
+ .long 125
+ .long 130
+ .section .debug_info.dwo,"",@progbits
+ .long 53 # Length of Unit
+ .short 4 # DWARF version number
+ .long 0 # Offset Into Abbrev. Section
+ .byte 8 # Address Size (in bytes)
+ .byte 1 # Abbrev [1] 0xb:0x2e DW_TAG_compile_unit
+ .byte 0 # DW_AT_GNU_dwo_name
+ .byte 1 # DW_AT_producer
+ .short 12 # DW_AT_language
+ .byte 2 # DW_AT_name
+ .quad 7615852067747431413 # DW_AT_GNU_dwo_id
+ .byte 2 # Abbrev [2] 0x19:0x1b DW_TAG_subprogram
+ .byte 0 # DW_AT_low_pc
+ .long .Lfunc_end0-.Lfunc_begin0 # DW_AT_high_pc
+ .byte 1 # DW_AT_frame_base
+ .byte 86
+ .byte 4 # DW_AT_name
+ .byte 1 # DW_AT_decl_file
+ .byte 19 # DW_AT_decl_line
+ # DW_AT_prototyped
+ .long 52 # DW_AT_type
+ # DW_AT_external
+ .byte 3 # Abbrev [3] 0x28:0xb DW_TAG_formal_parameter
+ .byte 2 # DW_AT_location
+ .byte 145
+ .byte 124
+ .byte 7 # DW_AT_name
+ .byte 1 # DW_AT_decl_file
+ .byte 19 # DW_AT_decl_line
+ .long 52 # DW_AT_type
+ .byte 0 # End Of Children Mark
+ .byte 4 # Abbrev [4] 0x34:0x4 DW_TAG_base_type
+ .byte 5 # DW_AT_name
+ .byte 5 # DW_AT_encoding
+ .byte 4 # DW_AT_byte_size
+ .byte 0 # End Of Children Mark
+ .long 41 # Length of Unit
+ .short 4 # DWARF version number
+ .long 0 # Offset Into Abbrev. Section
+ .byte 8 # Address Size (in bytes)
+ .byte 1 # Abbrev [1] 0xb:0x22 DW_TAG_compile_unit
+ .byte 0 # DW_AT_GNU_dwo_name
+ .byte 1 # DW_AT_producer
+ .short 12 # DW_AT_language
+ .byte 3 # DW_AT_name
+ .quad 2037650261599692324 # DW_AT_GNU_dwo_id
+ .byte 5 # Abbrev [5] 0x19:0xf DW_TAG_subprogram
+ .byte 1 # DW_AT_low_pc
+ .long .Lfunc_end1-.Lfunc_begin1 # DW_AT_high_pc
+ .byte 1 # DW_AT_frame_base
+ .byte 86
+ .byte 6 # DW_AT_name
+ .byte 2 # DW_AT_decl_file
+ .byte 22 # DW_AT_decl_line
+ .long 40 # DW_AT_type
+ # DW_AT_external
+ .byte 4 # Abbrev [4] 0x28:0x4 DW_TAG_base_type
+ .byte 5 # DW_AT_name
+ .byte 5 # DW_AT_encoding
+ .byte 4 # DW_AT_byte_size
+ .byte 0 # End Of Children Mark
+ .section .debug_abbrev.dwo,"",@progbits
+ .byte 1 # Abbreviation Code
+ .byte 17 # DW_TAG_compile_unit
+ .byte 1 # DW_CHILDREN_yes
+ .ascii "\260B" # DW_AT_GNU_dwo_name
+ .ascii "\202>" # DW_FORM_GNU_str_index
+ .byte 37 # DW_AT_producer
+ .ascii "\202>" # DW_FORM_GNU_str_index
+ .byte 19 # DW_AT_language
+ .byte 5 # DW_FORM_data2
+ .byte 3 # DW_AT_name
+ .ascii "\202>" # DW_FORM_GNU_str_index
+ .ascii "\261B" # DW_AT_GNU_dwo_id
+ .byte 7 # DW_FORM_data8
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 2 # Abbreviation Code
+ .byte 46 # DW_TAG_subprogram
+ .byte 1 # DW_CHILDREN_yes
+ .byte 17 # DW_AT_low_pc
+ .ascii "\201>" # DW_FORM_GNU_addr_index
+ .byte 18 # DW_AT_high_pc
+ .byte 6 # DW_FORM_data4
+ .byte 64 # DW_AT_frame_base
+ .byte 24 # DW_FORM_exprloc
+ .byte 3 # DW_AT_name
+ .ascii "\202>" # DW_FORM_GNU_str_index
+ .byte 58 # DW_AT_decl_file
+ .byte 11 # DW_FORM_data1
+ .byte 59 # DW_AT_decl_line
+ .byte 11 # DW_FORM_data1
+ .byte 39 # DW_AT_prototyped
+ .byte 25 # DW_FORM_flag_present
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .byte 63 # DW_AT_external
+ .byte 25 # DW_FORM_flag_present
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 3 # Abbreviation Code
+ .byte 5 # DW_TAG_formal_parameter
+ .byte 0 # DW_CHILDREN_no
+ .byte 2 # DW_AT_location
+ .byte 24 # DW_FORM_exprloc
+ .byte 3 # DW_AT_name
+ .ascii "\202>" # DW_FORM_GNU_str_index
+ .byte 58 # DW_AT_decl_file
+ .byte 11 # DW_FORM_data1
+ .byte 59 # DW_AT_decl_line
+ .byte 11 # DW_FORM_data1
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 4 # Abbreviation Code
+ .byte 36 # DW_TAG_base_type
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .ascii "\202>" # DW_FORM_GNU_str_index
+ .byte 62 # DW_AT_encoding
+ .byte 11 # DW_FORM_data1
+ .byte 11 # DW_AT_byte_size
+ .byte 11 # DW_FORM_data1
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 5 # Abbreviation Code
+ .byte 46 # DW_TAG_subprogram
+ .byte 0 # DW_CHILDREN_no
+ .byte 17 # DW_AT_low_pc
+ .ascii "\201>" # DW_FORM_GNU_addr_index
+ .byte 18 # DW_AT_high_pc
+ .byte 6 # DW_FORM_data4
+ .byte 64 # DW_AT_frame_base
+ .byte 24 # DW_FORM_exprloc
+ .byte 3 # DW_AT_name
+ .ascii "\202>" # DW_FORM_GNU_str_index
+ .byte 58 # DW_AT_decl_file
+ .byte 11 # DW_FORM_data1
+ .byte 59 # DW_AT_decl_line
+ .byte 11 # DW_FORM_data1
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .byte 63 # DW_AT_external
+ .byte 25 # DW_FORM_flag_present
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 0 # EOM(3)
+ .section .debug_line.dwo,"",@progbits
+.Ltmp4:
+ .long (.Ltmp5-.Ltmp4)-4
+ .short 2
+ .long (.Ltmp6-.Ltmp4)-10
+ .byte 1
+ .byte 1
+ .byte -5
+ .byte 14
+ .byte 1
+ .byte 0
+ .byte 0
+.Ltmp6:
+.Ltmp5:
+ .section .debug_addr,"",@progbits
+ .quad .Lfunc_begin0
+ .quad .Lfunc_begin1
+ .section .debug_pubnames,"",@progbits
+ .long .LpubNames_end0-.LpubNames_begin0 # Length of Public Names Info
+.LpubNames_begin0:
+ .short 2 # DWARF Version
+ .long .Lcu_begin0 # Offset of Compilation Unit Info
+ .long 48 # Compilation Unit Length
+ .long 25 # DIE offset
+ .asciz "func" # External Name
+ .long 0 # End Mark
+.LpubNames_end0:
+ .long .LpubNames_end1-.LpubNames_begin1 # Length of Public Names Info
+.LpubNames_begin1:
+ .short 2 # DWARF Version
+ .long .Lcu_begin1 # Offset of Compilation Unit Info
+ .long 48 # Compilation Unit Length
+ .long 25 # DIE offset
+ .asciz "main" # External Name
+ .long 0 # End Mark
+.LpubNames_end1:
+ .section .debug_pubtypes,"",@progbits
+ .long .LpubTypes_end0-.LpubTypes_begin0 # Length of Public Types Info
+.LpubTypes_begin0:
+ .short 2 # DWARF Version
+ .long .Lcu_begin0 # Offset of Compilation Unit Info
+ .long 48 # Compilation Unit Length
+ .long 52 # DIE offset
+ .asciz "int" # External Name
+ .long 0 # End Mark
+.LpubTypes_end0:
+ .long .LpubTypes_end1-.LpubTypes_begin1 # Length of Public Types Info
+.LpubTypes_begin1:
+ .short 2 # DWARF Version
+ .long .Lcu_begin1 # Offset of Compilation Unit Info
+ .long 48 # Compilation Unit Length
+ .long 40 # DIE offset
+ .asciz "int" # External Name
+ .long 0 # End Mark
+.LpubTypes_end1:
+
+ .ident "clang version 5.0.0 (trunk 302855) (llvm/trunk 302853)"
+ .ident "clang version 5.0.0 (trunk 302855) (llvm/trunk 302853)"
+ .section ".note.GNU-stack","",@progbits
+ .section .debug_line,"",@progbits
+.Lline_table_start0:
diff --git a/gdb/testsuite/gdb.dwarf2/fission-multi-cu.exp b/gdb/testsuite/gdb.dwarf2/fission-multi-cu.exp
new file mode 100644
index 0000000..1f23c5b6
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/fission-multi-cu.exp
@@ -0,0 +1,67 @@
+# Copyright 2012-2017 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+load_lib dwarf.exp
+
+# We run objcopy locally to split out the .dwo file.
+if [is_remote host] {
+ return 0
+}
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if ![dwarf2_support] {
+ return 0
+}
+
+# This test can only be run on x86-64 targets.
+if {![istarget x86_64-*] || ![is_lp64_target]} {
+ return 0
+}
+
+standard_testfile .S
+
+if [build_executable_from_fission_assembler \
+ "$testfile.exp" "$binfile" "$srcfile" {nodebug}] {
+ return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+# Make sure we can find the .dwo file, regardless of whether we're
+# running in parallel mode.
+gdb_test_no_output "set debug-file-directory [file dirname $binfile]" \
+ "set debug-file-directory"
+gdb_load $binfile
+
+if ![runto_main] {
+ return -1
+}
+
+# Do a few basic things to verify we're finding the DWO debug info.
+
+gdb_test "ptype main" "type = int \\(\\)"
+gdb_test "ptype func" "type = int \\(int\\)"
+
+gdb_test "frame" "#0 *main \\(\\) at ${testfile}2\\.c:$decimal.*" \
+ "frame in main"
+
+gdb_test "break func" "Breakpoint.*at.* file .*${testfile}1\\.c, line .*"
+
+gdb_test "continue" "Breakpoint.* func \\(arg=-1\\).*" \
+ "continue to func"
+
+gdb_test "frame" "#0 *func \\(arg=-1\\) at ${testfile}1\\.c:$decimal.*" \
+ "frame in func"
diff --git a/gdb/testsuite/gdb.dwarf2/fission-multi-cu1.c b/gdb/testsuite/gdb.dwarf2/fission-multi-cu1.c
new file mode 100644
index 0000000..d93e2f9
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/fission-multi-cu1.c
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2012-2017 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+int
+func (int arg)
+{
+ return arg + 1;
+}
diff --git a/gdb/testsuite/gdb.dwarf2/fission-multi-cu2.c b/gdb/testsuite/gdb.dwarf2/fission-multi-cu2.c
new file mode 100644
index 0000000..053b3ea
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/fission-multi-cu2.c
@@ -0,0 +1,24 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2012-2017 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+void func ();
+
+int
+main ()
+{
+ func (-1);
+}