6d5f0679fe
break-asm-file.exp has some manually written dwarf to create some line
number entries like this,
[0x0000013d] Extended opcode 2: set Address to 0x40053f
[0x00000144] Advance Line by 4 to 7
[0x00000146] Copy
[0x00000147] Extended opcode 2: set Address to 0x400541
[0x0000014e] Advance Line by 1 to 8
[0x00000150] Copy
[0x00000151] Extended opcode 2: set Address to 0x400547
[0x00000158] Extended opcode 1: End of Sequence
0x40053f is the start address of function func, and is mapped to line
7. 0x400541 is within function func, and is mapped to line 8.
(gdb) disassemble /r 0x40053f,+8
Dump of assembler code from 0x40053f to 0x400547:
0x000000000040053f <func+0>: 00 00 add %al,(%rax)
0x0000000000400541 <func+2>: 00 00 add %al,(%rax)
0x0000000000400543 <func+4>: 00 00 add %al,(%rax)
0x0000000000400545 <func+6>: 00 00 add %al,(%rax)
in the following test,
(gdb) break a/break-asm-file0.s:func
Breakpoint 1 at 0x40053f: file a/break-asm-file0.s, line 7.
As we can see, breakpoint is set at the start address of function func
on x86, which means no prologue is skipped. On other targets, such as
arm and aarch64, breakpoint is set at the address *after* the start
address, which is mapped to line 8. Then test fails.
In fact, it is lucky this test doesn't fail on x86 and x86_64, whose
gdbarch method skip_prologue doesn't reply on skip_prologue_using_sal
if producer isn't clang.
if (find_pc_partial_function (start_pc, NULL, &func_addr, NULL))
{
CORE_ADDR post_prologue_pc
= skip_prologue_using_sal (gdbarch, func_addr);
struct compunit_symtab *cust = find_pc_compunit_symtab (func_addr);
/* Clang always emits a line note before the prologue and another
one after. We trust clang to emit usable line notes. */
if (post_prologue_pc
&& (cust != NULL
&& COMPUNIT_PRODUCER (cust) != NULL
&& startswith (COMPUNIT_PRODUCER (cust), "clang ")))
return max (start_pc, post_prologue_pc);
}
so it doesn't return and go further to prologue analyser. Since ".int 0"
isn't an instruction of prologue, nothing is skipped, starting address
is used, and test passes.
however, on targets which don't have such producer checking, the first
line number entry is skipped, and skip_prologue_using_sal returns sal
represents the second line number entry.
The idea of this patch is to force GDB stop at somewhere which is stilled
mapped to line 7 after skipping prologue. I choose to add a new line
number entry for the following instruction but mapped to the same line (7),
because I see the comments in dwarf2read.c,
... fact that two consecutive
line number entries for the same line is a heuristic used by gcc
to denote the end of the prologue.
then the line table becomes:
[0x000000d4] Extended opcode 2: set Address to 0x400529
[0x000000db] Advance Line by 4 to 7
[0x000000dd] Copy
[0x000000de] Extended opcode 2: set Address to 0x40052a
[0x000000e5] Advance Line by 0 to 7
[0x000000e7] Copy
[0x000000e8] Extended opcode 2: set Address to 0x40052b
[0x000000ef] Advance Line by 1 to 8
[0x000000f1] Copy
[0x000000f2] Extended opcode 2: set Address to 0x40052c
[0x000000f9] Extended opcode 1: End of Sequence
gdb/testsuite:
2015-03-26 Yao Qi <yao.qi@linaro.org>
PR testsuite/18139
* gdb.linespec/break-asm-file0.s (func): New label .Lfunc_2.
Add a line number entry for the same line.
* gdb.linespec/break-asm-file1.s (func): New label .Lfunc_2.
Add a line number entry for the same line.
259 lines
6.2 KiB
ArmAsm
259 lines
6.2 KiB
ArmAsm
/* This testcase is part of GDB, the GNU debugger.
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Copyright 2004-2015 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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.text
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.Lbegin_text1:
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.globl _func3
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_func3:
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.globl func3
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.type func3, %function
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func3:
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.Lbegin_func3:
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nop
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nop
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.Lend_func3:
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.size func3, .-func3
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_func:
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.type func, %function
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func:
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.Lbegin_func:
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nop
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.Lfunc_1:
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nop
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.Lfunc_2:
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nop
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.Lend_func:
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.size func, .-func
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.Lend_text1:
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/* Debug information */
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.section .debug_info
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.Lcu1_begin:
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/* CU header */
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.4byte .Lcu1_end - .Lcu1_start /* Length of Compilation Unit */
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.Lcu1_start:
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.2byte 2 /* DWARF Version */
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.4byte .Labbrev1_begin /* Offset into abbrev section */
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.byte 4 /* Pointer size */
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/* CU die */
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.uleb128 1 /* Abbrev: DW_TAG_compile_unit */
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.4byte .Lline1_begin /* DW_AT_stmt_list */
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.4byte .Lend_text1 /* DW_AT_high_pc */
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.4byte .Lbegin_text1 /* DW_AT_low_pc */
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.ascii "b/break-asm-file0.s\0" /* DW_AT_name */
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.ascii "GNU C 3.3.3\0" /* DW_AT_producer */
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.2byte 0x8001 /* DW_AT_language (Mips Assembler) */
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/* func3 */
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.uleb128 2 /* Abbrev: DW_TAG_subprogram */
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.byte 1 /* DW_AT_external */
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.byte 1 /* DW_AT_decl_file */
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.byte 2 /* DW_AT_decl_line */
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.ascii "func3\0" /* DW_AT_name */
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.4byte .Ltype_int-.Lcu1_begin /* DW_AT_type */
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.4byte .Lbegin_func3 /* DW_AT_low_pc */
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.4byte .Lend_func3 /* DW_AT_high_pc */
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.byte 1 /* DW_AT_frame_base: length */
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.byte 0x55 /* DW_AT_frame_base: DW_OP_reg5 */
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/* func */
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.uleb128 2 /* Abbrev: DW_TAG_subprogram */
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.byte 0 /* DW_AT_external */
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.byte 1 /* DW_AT_decl_file */
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.byte 4 /* DW_AT_decl_line */
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.ascii "func\0" /* DW_AT_name */
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.4byte .Ltype_int-.Lcu1_begin /* DW_AT_type */
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.4byte .Lbegin_func /* DW_AT_low_pc */
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.4byte .Lend_func /* DW_AT_high_pc */
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.byte 1 /* DW_AT_frame_base: length */
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.byte 0x55 /* DW_AT_frame_base: DW_OP_reg5 */
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.Ltype_int:
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.uleb128 3 /* Abbrev: DW_TAG_base_type */
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.ascii "int\0" /* DW_AT_name */
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.byte 4 /* DW_AT_byte_size */
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.byte 5 /* DW_AT_encoding */
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.byte 0 /* End of children of CU */
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.Lcu1_end:
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/* Abbrev table */
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.section .debug_abbrev
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.Labbrev1_begin:
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.uleb128 1 /* Abbrev code */
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.uleb128 0x11 /* DW_TAG_compile_unit */
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.byte 1 /* has_children */
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.uleb128 0x10 /* DW_AT_stmt_list */
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.uleb128 0x6 /* DW_FORM_data4 */
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.uleb128 0x12 /* DW_AT_high_pc */
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.uleb128 0x1 /* DW_FORM_addr */
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.uleb128 0x11 /* DW_AT_low_pc */
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.uleb128 0x1 /* DW_FORM_addr */
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.uleb128 0x3 /* DW_AT_name */
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.uleb128 0x8 /* DW_FORM_string */
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.uleb128 0x25 /* DW_AT_producer */
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.uleb128 0x8 /* DW_FORM_string */
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.uleb128 0x13 /* DW_AT_language */
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.uleb128 0x5 /* DW_FORM_data2 */
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.byte 0x0 /* Terminator */
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.byte 0x0 /* Terminator */
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.uleb128 2 /* Abbrev code */
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.uleb128 0x2e /* DW_TAG_subprogram */
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.byte 0 /* has_children */
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.uleb128 0x3f /* DW_AT_external */
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.uleb128 0xc /* DW_FORM_flag */
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.uleb128 0x3a /* DW_AT_decl_file */
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.uleb128 0xb /* DW_FORM_data1 */
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.uleb128 0x3b /* DW_AT_decl_line */
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.uleb128 0xb /* DW_FORM_data1 */
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.uleb128 0x3 /* DW_AT_name */
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.uleb128 0x8 /* DW_FORM_string */
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.uleb128 0x49 /* DW_AT_type */
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.uleb128 0x13 /* DW_FORM_ref4 */
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.uleb128 0x11 /* DW_AT_low_pc */
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.uleb128 0x1 /* DW_FORM_addr */
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.uleb128 0x12 /* DW_AT_high_pc */
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.uleb128 0x1 /* DW_FORM_addr */
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.uleb128 0x40 /* DW_AT_frame_base */
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.uleb128 0xa /* DW_FORM_block1 */
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.byte 0x0 /* Terminator */
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.byte 0x0 /* Terminator */
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.uleb128 3 /* Abbrev code */
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.uleb128 0x24 /* DW_TAG_base_type */
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.byte 0 /* has_children */
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.uleb128 0x3 /* DW_AT_name */
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.uleb128 0x8 /* DW_FORM_string */
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.uleb128 0xb /* DW_AT_byte_size */
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.uleb128 0xb /* DW_FORM_data1 */
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.uleb128 0x3e /* DW_AT_encoding */
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.uleb128 0xb /* DW_FORM_data1 */
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.byte 0x0 /* Terminator */
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.byte 0x0 /* Terminator */
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.byte 0x0 /* Terminator */
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.byte 0x0 /* Terminator */
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/* Line table */
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.section .debug_line
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.Lline1_begin:
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.4byte .Lline1_end - .Lline1_start /* Initial length */
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.Lline1_start:
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.2byte 2 /* Version */
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.4byte .Lline1_lines - .Lline1_hdr /* header_length */
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.Lline1_hdr:
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.byte 1 /* Minimum insn length */
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.byte 1 /* default_is_stmt */
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.byte 1 /* line_base */
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.byte 1 /* line_range */
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.byte 0x10 /* opcode_base */
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/* Standard lengths */
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.byte 0
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.byte 1
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.byte 1
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.byte 1
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.byte 1
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.byte 0
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.byte 0
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.byte 0
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.byte 1
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.byte 0
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.byte 0
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.byte 1
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.byte 0
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.byte 0
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.byte 0
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/* Include directories */
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.byte 0
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/* File names */
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.ascii "b/break-asm-file0.s\0"
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.uleb128 0
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.uleb128 0
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.uleb128 0
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.byte 0
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.Lline1_lines:
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.byte 0 /* DW_LNE_set_address */
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.uleb128 5
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.byte 2
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.4byte .Lbegin_func3
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.byte 3 /* DW_LNS_advance_line */
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.sleb128 1 /* ... to 2 */
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.byte 1 /* DW_LNS_copy */
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.byte 0 /* DW_LNE_set_address */
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.uleb128 5
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.byte 2
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.4byte .Lbegin_func3+1
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.byte 3 /* DW_LNS_advance_line */
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.sleb128 1 /* ... to 3 */
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.byte 1 /* DW_LNS_copy */
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.byte 0 /* DW_LNE_set_address */
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.uleb128 5
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.byte 2
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.4byte .Lbegin_func
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.byte 3 /* DW_LNS_advance_line */
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.sleb128 4 /* ... to 7 */
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.byte 1 /* DW_LNS_copy */
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.byte 0 /* DW_LNE_set_address */
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.uleb128 5
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.byte 2
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.4byte .Lfunc_1
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/* A line number entry for the same line (7) denotes the end */
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/* of prologue. */
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.byte 3 /* DW_LNS_advance_line */
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.sleb128 0 /* ... to 7 */
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.byte 1 /* DW_LNS_copy */
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.byte 0 /* DW_LNE_set_address */
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.uleb128 5
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.byte 2
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.4byte .Lfunc_2
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.byte 3 /* DW_LNS_advance_line */
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.sleb128 1 /* ... to 8 */
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.byte 1 /* DW_LNS_copy */
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.byte 0 /* DW_LNE_set_address */
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.uleb128 5
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.byte 2
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.4byte .Lend_func
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.byte 0 /* DW_LNE_end_of_sequence */
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.uleb128 1
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.byte 1
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.Lline1_end:
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