[llvm-dev] Filename's in DIBuileder

Robinson, Paul via llvm-dev
Tue, 01 Sep 2020 17:10:24 -0000

Try using $PWD/test.cpp on the clang command line.  I am seeing the duplicate
DIFile entries, but not yet able to reproduce a .debug_line section with
multiple directory entries.
--paulr

From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of Tomar,
Sourabh Singh via llvm-dev
Sent: Tuesday, September 1, 2020 1:07 PM
To: Umesh Kalappa <umesh.kalappa0 at gmail.com>; cfe-dev at lists.llvm.org
Developers <cfe-dev at lists.llvm.org>
Cc: llvm-dev at lists.llvm.org
Subject: Re: [llvm-dev] Filename's in DIBuileder


[AMD Official Use Only - Internal Distribution Only]

Didn't observed this on trunk(Using attached test.cpp): Trunk at
29ae4485950ed76faa94dabbd13bbe91d2b5c750

$clang++ -std=c++14 -g test.cpp -c -S -emit-llvm -o - | awk /DIFile/
!3 = !DIFile(filename: "test.cpp", directory: "/home/")

$ clang++ -std=c++14 -g test.cpp -c -o - | llvm-dwarfdump -debug-line -
[...]
file_names[  1]:
           name: "test.cpp"
      dir_index: 0
       mod_time: 0x00000000
         length: 0x00000000
[...]

Did I missed something, while reproducing ? ?

--Sourabh

From: llvm-dev <llvm-dev-bounces at lists.llvm.org<mailto:llvm-dev-bounces
at lists.llvm.org>> On Behalf Of Umesh Kalappa via llvm-dev
Sent: Tuesday, September 1, 2020 9:50 PM
To: LLVM Developers Mailing List <llvm-dev at
lists.llvm.org<mailto:llvm-dev at lists.llvm.org>>; cfe-dev at
lists.llvm.org<mailto:cfe-dev at lists.llvm.org> Developers <cfe-dev at
lists.llvm.org<mailto:cfe-dev at lists.llvm.org>>
Subject: [llvm-dev] Filename's in DIBuileder

[CAUTION: External Email]
Hi All ,

We have a scenario in our debugger to handle the file index in the debug_ine
info like

$llvm-dwarfdump -debug-line test.o
file_names[  1]:
           name: "test.cpp"
      dir_index: 0
       mod_time: 0x00000000
         length: 0x00000000
file_names[  2]:
           name: "test.cpp"
      dir_index: 1
       mod_time: 0x00000000
         length: 0x00000000

Address            Line   Column File   ISA Discriminator Flags
------------------ ------ ------ ------ --- ------------- -------------
0x0000000000000000     12      0      1   0             0  is_stmt
0x0000000000000008     13      1      1   0             0  is_stmt prologue_end
0x0000000000000010     16      0      1   0             0  is_stmt
0x0000000000000018     17      1      1   0             0  is_stmt prologue_end
0x0000000000000020     20      0      1   0             0  is_stmt
0x0000000000000028     21      9      1   0             0  is_stmt prologue_end
0x000000000000002f     22      9      1   0             0  is_stmt
0x0000000000000032     22     10      1   0             0
0x0000000000000035     22      7      1   0             0
0x000000000000003c     23      1      1   0             0  is_stmt
0x0000000000000040     25      0      1   0             0  is_stmt
0x0000000000000044     25     13      1   0             0  is_stmt prologue_end
0x0000000000000080      0      0      2   0             0  is_stmt
0x000000000000008b      0      0      2   0             0  is_stmt end_sequence


the debug info is emitted by the DIBuilder like

!3 = !DIFile(filename: "/folk/tmp/test/test.cpp", directory:
"/folk/tmp/test")
!45 = distinct !DISubprogram(linkageName: "_GLOBAL__sub_I_test.cpp",
scope: !3, file: !3, type: !46, flags: DIFlagArtificial, spFlags:
DISPFlagLocalToUnit | DISPFlagDefinition, unit: !2, retainedNodes: !4)

!8 = !DIFile(filename: "test.cpp", directory:
"/folk/tmp/test")
!16 = !DISubprogram(name: "proc", linkageName:
"_ZN4test4procEv", scope: !9, file: !8, line: 8, type: !12, scopeLine:
8, flags: DIFlagPublic | DIFlagPrototyped, spFlags: 0)

Latest clang trunk used like

$clang -std=c++14  -g -eimit-llvm -S   /folk/tmp/test/test.cpp

and the respective files like test.cc ,test.ll and test.s are attached in the
mail for the reference.

the scenario is that why the file-name 's are different is both cases
,where "ZN4test4procEv" is the user defined function and
"_GLOBAL__sub_I_test.cpp"
is generated for the static initialisation ,which leads to the  two file index
like 1 and 2 for  two files in the filename table ,that confuse our debugger .

So we like to hear from experts here  ,before we investigate the DIBuilder to
fix the same.

Thank you
~Umesh
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