[lld] [llvm] [Symbolizer] Support for Missing Line Numbers. (PR #82240)
via llvm-commits
llvm-commits at lists.llvm.org
Sun Jul 28 22:02:19 PDT 2024
================
@@ -0,0 +1,252 @@
+## Test the "--skip-line-zero"(abbrev. 'SLZ') option.
+##
+## This test uses handcrafted assembly to produce the following line table:
+## Address Line Column File ISA Discriminator OpIndex Flags
+## ------------------ ------ ------ ------ --- ------------- ------- -------------
+## 0x0000000000001710 1 0 1 0 0 0
+## 0x0000000000001714 0 0 1 0 0 0
+## 0x0000000000001719 1 0 1 0 0 0
+## 0x000000000000171b 1 0 1 0 0 0 end_sequence
+## 0x00000000000016c0 0 0 1 0 0 0
+## 0x00000000000016cf 2 0 1 0 0 0
+## 0x00000000000016d4 0 0 1 0 0 0
+## 0x00000000000016d9 0 0 1 0 0 0
+## 0x00000000000016df 0 0 1 0 0 0 end_sequence
+
+# REQUIRES: x86-registered-target
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+
+## Check that without '--skip-line-zero', line zero is displayed for a line-table entry which has no source correspondence.
+# RUN: llvm-symbolizer --obj=%t.o 0x16d4 | FileCheck --strict-whitespace --match-full-lines --check-prefix=SLZ-DISABLE %s
+
+# SLZ-DISABLE:main
+# SLZ-DISABLE-NEXT:main.c:0:0
+
+## Check that the '--skip-line-zero' does not cross sequence boundaries.
+## If it fails to find in the current sequence then line zero is returned for the queried address.
+# RUN: llvm-symbolizer --obj=%t.o --skip-line-zero 0x16c0 | FileCheck --strict-whitespace --match-full-lines --check-prefix=SLZ-FAIL-ACROSS-SEQ %s
+
+# SLZ-FAIL-ACROSS-SEQ:main
+# SLZ-FAIL-ACROSS-SEQ-NEXT:main.c:0:0
+
+## Check that with '--skip-line-zero', the last non-zero line in the current sequence is displayed.
+# RUN: llvm-symbolizer --obj=%t.o --skip-line-zero 0x1717 | FileCheck --strict-whitespace --match-full-lines --check-prefix=SLZ-WITHIN-SEQ %s
+
+# SLZ-WITHIN-SEQ:foo
+# SLZ-WITHIN-SEQ-NEXT:main.c:1:0 (approximate)
+
+## Check that with '--skip-line-zero', multiple line zero rows are skipped within the current sequence.
+# RUN: llvm-symbolizer --obj=%t.o --skip-line-zero 0x16d9 | FileCheck --strict-whitespace --match-full-lines --check-prefix=SLZ-MULTIPLE-ROWS %s
+
+# SLZ-MULTIPLE-ROWS:main
+# SLZ-MULTIPLE-ROWS-NEXT:main.c:2:0 (approximate)
+
+## Check that '--skip-line-zero' only affects the line zero addresses when more than one address is specified.
+# RUN: llvm-symbolizer --obj=%t.o --skip-line-zero 0x16d4 0x1719 | FileCheck --strict-whitespace --match-full-lines --check-prefixes=SLZ-ENABLE,SLZ-NO-APPROX %s
+
+# SLZ-ENABLE:main
+# SLZ-ENABLE-NEXT:main.c:2:0 (approximate)
+# SLZ-NO-APPROX:foo
+# SLZ-NO-APPROX-NEXT:main.c:1:0
+
+## Check to ensure that '--skip-line-zero' with '--verbose' enabled displays approximate flag in verbose ouptut.
+# RUN: llvm-symbolizer --obj=%t.o --skip-line-zero --verbose 0x1717 | FileCheck --strict-whitespace --match-full-lines --check-prefix=SLZ-VERBOSE %s
+
+# SLZ-VERBOSE:foo
+# SLZ-VERBOSE-NEXT: Filename: main.c
+# SLZ-VERBOSE-NEXT: Function start filename: main.c
+# SLZ-VERBOSE-NEXT: Function start line: 1
+# SLZ-VERBOSE-NEXT: Function start address: 0x1710
+# SLZ-VERBOSE-NEXT: Line: 1
+# SLZ-VERBOSE-NEXT: Column: 0
+# SLZ-VERBOSE-NEXT: Approximate: true
+
+## Check to ensure that '--skip-line-zero' with '--output-style=JSON' displays approximate flag in JSON output.
+# RUN: llvm-symbolizer --obj=%t.o --skip-line-zero --output-style=JSON 0x1717 | FileCheck --strict-whitespace --match-full-lines --check-prefix=SLZ-JSON %s
+
+# SLZ-JSON:[{"Address":"0x1717","ModuleName":"{{.*}}{{[/|\]+}}test{{[/|\]+}}tools{{[/|\]+}}llvm-symbolizer{{[/|\]+}}Output{{[/|\]+}}skip-line-zero.s.tmp.o","Symbol":[{"Approximate":true,"Column":0,"Discriminator":0,"FileName":"main.c","FunctionName":"foo","Line":1,"StartAddress":"0x1710","StartFileName":"main.c","StartLine":1}]}]
+
+## main.c
+## __attribute__((section("def"))) int foo() { return 1234; }
+## int main(void) { return foo()+5678; }
+##
+## Generated using
+## clang -S -gdwarf-4 --target=x86_64-pc-linux -fdebug-prefix-map=/tmp="" main.c -o main.s
+##
+## Sections belonging to code segment(.text) are removed. Sections related to debug information(other than .debug_line and .debug_abbrev) are modified. Section .debug_line is handwritten.
+
+ .section .debug_abbrev,"", at progbits
+ .byte 1 # Abbreviation Code
+ .byte 17 # DW_TAG_compile_unit
+ .byte 1 # DW_CHILDREN_yes
+ .byte 37 # DW_AT_producer
+ .byte 14 # DW_FORM_strp
+ .byte 19 # DW_AT_language
+ .byte 5 # DW_FORM_data2
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 16 # DW_AT_stmt_list
+ .byte 23 # DW_FORM_sec_offset
+ .byte 17 # DW_AT_low_pc
+ .byte 1 # DW_FORM_addr
+ .byte 85 # DW_AT_ranges
+ .byte 23 # DW_FORM_sec_offset
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 2 # Abbreviation Code
+ .byte 46 # DW_TAG_subprogram
+ .byte 0 # DW_CHILDREN_no
+ .byte 17 # DW_AT_low_pc
+ .byte 1 # DW_FORM_addr
+ .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
+ .byte 14 # DW_FORM_strp
+ .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 3 # Abbreviation Code
+ .byte 46 # DW_TAG_subprogram
+ .byte 0 # DW_CHILDREN_no
+ .byte 17 # DW_AT_low_pc
+ .byte 1 # DW_FORM_addr
+ .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
+ .byte 14 # DW_FORM_strp
+ .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 4 # Abbreviation Code
+ .byte 36 # DW_TAG_base_type
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .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 0 # EOM(3)
+ .section .debug_info,"", at progbits
+.Lcu_begin0:
+ .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+ .short 4 # DWARF version number
+ .long .debug_abbrev # Offset Into Abbrev. Section
+ .byte 8 # Address Size (in bytes)
+ .byte 1 # Abbrev [1] 0xb:0x55 DW_TAG_compile_unit
+ .long .Linfo_string0 # DW_AT_producer
+ .short 29 # DW_AT_language
+ .long .Linfo_string1 # DW_AT_name
+ .long .Lline_table_start0 # DW_AT_stmt_list
+ .quad 0 # DW_AT_low_pc
+ .long .Ldebug_ranges0 # DW_AT_ranges
+ .byte 2 # Abbrev [2] 0x26:0x19 DW_TAG_subprogram
+ .quad 0x1710 # DW_AT_low_pc (.Lfunc_begin0)
+ .long 0x171b-0x1710 # DW_AT_high_pc(.Lfunc_end0-.Lfunc_begin0)
+ .byte 1 # DW_AT_frame_base
+ .byte 86
+ .long .Linfo_string2 # DW_AT_name
+ .byte 1 # DW_AT_decl_file
+ .byte 1 # DW_AT_decl_line
+ .long 88 # DW_AT_type
+ # DW_AT_external
+ .byte 3 # Abbrev [3] 0x3f:0x19 DW_TAG_subprogram
+ .quad 0x16c0 # DW_AT_low_pc (.Lfunc_begin1)
+ .long 0x16df-0x16c0 # DW_AT_high_pc (.Lfunc_end1-.Lfunc_begin1)
+ .byte 1 # DW_AT_frame_base
+ .byte 86
+ .long .Linfo_string4 # DW_AT_name
+ .byte 1 # DW_AT_decl_file
+ .byte 2 # DW_AT_decl_line
+ # DW_AT_prototyped
+ .long 88 # DW_AT_type
+ # DW_AT_external
+ .byte 4 # Abbrev [4] 0x58:0x7 DW_TAG_base_type
+ .long .Linfo_string3 # DW_AT_name
+ .byte 5 # DW_AT_encoding
+ .byte 4 # DW_AT_byte_size
+ .byte 0 # End Of Children Mark
+.Ldebug_info_end0:
+ .section .debug_ranges,"", at progbits
+.Ldebug_ranges0:
+ .quad 0x1710 #.Lfunc_begin0
+ .quad 0x171b #.Lfunc_end0
+ .quad 0x16c0 #.Lfunc_begin1
+ .quad 0x16df #.Lfunc_end1
+ .quad 0
+ .quad 0
+ .section .debug_str,"MS", at progbits,1
+.Linfo_string0:
+ .asciz "" # string offset=0
+.Linfo_string1:
+ .asciz "main.c" # string offset=113
+.Linfo_string2:
+ .asciz "foo" # string offset=120
+.Linfo_string3:
+ .asciz "int" # string offset=124
+.Linfo_string4:
+ .asciz "main" # string offset=128
+ .section .debug_line,"", at progbits
+.Lline_table_start0:
+ .long .Lunit_end - .Lunit_start # unit length
+.Lunit_start:
+ .short 4 # version
+ .long .Lprologue_end - .Lprologue_start # header length
+.Lprologue_start:
+ .byte 1 # minimum_instruction_length
+ .byte 1 # maximum_operations_per_instruction
+ .byte 0 # default_is_stmt
+ .byte -5 # line_base
+ .byte 14 # line_range
+ .byte 13 # opcode_base
+ .byte 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1 # arguments in standard opcodes
+ .byte 0 # end of include directories
+ .asciz "main.c" # filename
+ .byte 0 # directory index
+ .byte 0 # modification time
+ .byte 0 # length of file (unavailable)
+ .byte 0 # end of filenames
+.Lprologue_end:
+ .byte 0x00, 9, 2 # DW_LNE_set_address
+ .quad 0x1710 # Address Value
+ .byte 0x01 # DW_LNS_copy
+ .byte 0x49 # (address += 4, line += -1, op-index += 0)
----------------
ampandey-1995 wrote:
> Maybe I'm missing something. My thoughts are that for the "WITHIN-SEQ" 0x1717 testcase, for the current table we would get the following output if --skip-line-zero had chosen the 0x1710 row..
>
> ```
> foo
> main.c:1:0 (approximate)
> ```
>
> ..and the same output if it had chosen the 0x1719 row. With the proposed table we would get that same output if the 0x1710 row was chosen but..
That is not the case with 0x1719. In the current line-table which is :-
```
Address Line Column File ISA Discriminator OpIndex Flags
------------------ ------ ------ ------ --- ------------- ------- -------------
0x0000000000001710 1 0 1 0 0 0
0x0000000000001714 0 0 1 0 0 0
0x0000000000001719 1 0 1 0 0 0
0x000000000000171b 1 0 1 0 0 0 end_sequence
0x00000000000016c0 0 0 1 0 0 0
0x00000000000016cf 2 0 1 0 0 0
0x00000000000016d4 0 0 1 0 0 0
0x00000000000016d9 0 0 1 0 0 0
0x00000000000016df 0 0 1 0 0 0 end_sequence
```
```
Symbolizer o/p
~$ llvm-symbolizer --obj=skip-line-zero.o --skip-line-zero 0x1719
foo
main.c:1:0
```
This is because in the line table we have found the non-zero line-entry first , this will not be an approximate value.
Check the lit test ```NO-APPROX```.
> ```
> foo
> main.c:1:2 (approximate)
> ```
>
> ..if the 0x1719 row was chosen.
The proposed line-table produced below having column entry as per your viewpoint.
```
Address Line Column File ISA Discriminator OpIndex Flags
------------------ ------ ------ ------ --- ------------- ------- -------------
0x0000000000001710 1 0 1 0 0 0
0x0000000000001714 0 0 1 0 0 0
0x0000000000001719 1 2 1 0 0 0
0x000000000000171b 1 2 1 0 0 0 end_sequence
0x00000000000016c0 0 0 1 0 0 0
0x00000000000016cf 2 0 1 0 0 0
0x00000000000016d4 0 0 1 0 0 0
0x00000000000016d9 0 0 1 0 0 0
0x00000000000016df 0 0 1 0 0 0 end_sequence
```
```
Symbolizer output will be
~$ llvm-symbolizer --obj=skip-line-zero1.o 0x1719 --skip-line-zero
foo
main.c:1:2
```
The address 0x1719 have non-zero line value so it would not be an 'approximate'.
https://github.com/llvm/llvm-project/pull/82240
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