Bug 2161820

Summary: Apparent issue with -fdebug-prefix-map
Product: [Fedora] Fedora Reporter: Orion Poplawski <orion>
Component: gccAssignee: Jakub Jelinek <jakub>
Status: CLOSED RAWHIDE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 38CC: aoliva, dmalcolm, fweimer, jakub, jlaw, jwakely, mcermak, mpolacek, msebor, nickc, sipoyare
Target Milestone: ---   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: gcc-13.0.1-0.7.fc39 Doc Type: If docs needed, set a value
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Story Points: ---
Clone Of: Environment:
Last Closed: 2023-03-22 02:27:11 UTC Type: Bug
Regression: --- Mount Type: ---
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Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2171460    
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Description Flags
Reproducer spec file none

Description Orion Poplawski 2023-01-18 01:43:58 UTC 
Description of problem:

With the update to gcc 13, ccache's test suite is failing complaining that debug-prefix-map is failing.  I reported it upstream to ccache (https://github.com/ccache/ccache/issues/1242#issuecomment-1386036279), and they responded:

This looks like a bug in GCC or binutils in Fedora Rawhide since -fdebug-prefix-map=FROM=TO does not work:

$ gcc --version | head -n 1
gcc (GCC) 13.0.0 20230115 (Red Hat 13.0.0-0)
$ as --version | head -n 1
GNU assembler version 2.39-6.fc38
$ touch test.c
$ gcc -g -fdebug-prefix-map=$PWD=XXX -c $PWD/test.c
$ grep -c $PWD test.o
2
$ grep -c XXX test.o
0

Compare with this:

$ gcc --version | head -n 1
gcc (Ubuntu 11.3.0-1ubuntu1~22.04) 11.3.0
$ as --version | head -n 1
GNU assembler (GNU Binutils for Ubuntu) 2.38
$ touch test.c
$ gcc -g -fdebug-prefix-map=$PWD=XXX -c $PWD/test.c
$ grep -c $PWD test.o
0
$ grep -c XXX test.o
2

Of course, I can't reproduce those results on my Fedora rawhide VM, but the test still fails so I think something is up.



Version-Release number of selected component (if applicable):
gcc-13.0.0-0.9.fc38.x86_64
Comment 1 Jakub Jelinek 2023-01-18 09:44:42 UTC 
Can't reproduce.
For empty test.c there isn't much debug info produced, but still I see
Contents of section .debug_str:
 0000 474e5520 43313720 31332e30 2e302032  GNU C17 13.0.0 2
 0010 30323330 31313520 28526564 20486174  0230115 (Red Hat
 0020 2031332e 302e302d 3029202d 6d736563   13.0.0-0) -msec
 0030 7572652d 706c7420 2d6d7475 6e653d70  ure-plt -mtune=p
 0040 6f776572 38202d6d 6370753d 706f7765  ower8 -mcpu=powe
 0050 7238202d 67005858 582f7465 73742e63  r8 -g.XXX/test.c
 0060 00                                   .               
When I try something non-empty:
int main () { return 0; }
I get:
readelf -wi a.o | grep 'tmp\|XXX'
    <12>   DW_AT_name        : (indirect string, offset: 0x0): XXX/a.c
    <16>   DW_AT_comp_dir    : XXX
Comment 2 Jakub Jelinek 2023-01-18 09:47:38 UTC 
Oh, and
readelf -wl a.o | grep 'tmp\|XXX'
  1	XXX
Comment 3 Orion Poplawski 2023-01-19 04:55:05 UTC 
Created attachment 1939079 [details]
Reproducer spec file

Okay, I think I've finally created a reproducer based on the actual test ccache runs.  It also shows a situation in which debug-prefix-map works and fails.

On rawhide I get:
+ cd debug-prefix-map-test-1.0.0
+ for dir in run.real run.real/dir1
+ mkdir -p run.real/include run.real/src
+ rm -f run
+ ln -s run.real run
+ cd run
+ cat
+ cat
+ CCACHE_DISABLE=1
+ CCACHE_COMPILER=
+ CCACHE_PREFIX=
+ /usr/bin/gcc -g -fdebug-prefix-map=/home/orion/debug-prefix-map-test/debug-prefix-map-test-1.0.0/run=some_name_not_likely_to_exist_in_path -Iinclude -c -fdiagnostics-color -o ./test.o src/test.c
+ readelf -wi test.o
+ grep -E '/home/orion/debug-prefix-map-test/debug-prefix-map-test-1.0.0/run|some_name_not_likely_to_exist_in_path'
    <12>   DW_AT_name        : (indirect line string, offset: 0x2b): some_name_not_likely_to_exist_in_path.real/src/test.c
    <16>   DW_AT_comp_dir    : (indirect line string, offset: 0x0): some_name_not_likely_to_exist_in_path.real
+ readelf -wl test.o
+ grep -E '/home/orion/debug-prefix-map-test/debug-prefix-map-test-1.0.0/run|some_name_not_likely_to_exist_in_path'
  0     (indirect line string, offset: 0x61): some_name_not_likely_to_exist_in_path.real
  1     (indirect line string, offset: 0x8c): some_name_not_likely_to_exist_in_path.real/src
  2     (indirect line string, offset: 0xbb): some_name_not_likely_to_exist_in_path.real/include
+ cd -
/home/orion/debug-prefix-map-test/debug-prefix-map-test-1.0.0
+ for dir in run.real run.real/dir1
+ mkdir -p run.real/dir1/include run.real/dir1/src
+ rm -f run
+ ln -s run.real run
+ cd run/dir1
+ cat
+ cat
+ CCACHE_DISABLE=1
+ CCACHE_COMPILER=
+ CCACHE_PREFIX=
+ /usr/bin/gcc -g -fdebug-prefix-map=/home/orion/debug-prefix-map-test/debug-prefix-map-test-1.0.0/run/dir1=some_name_not_likely_to_exist_in_path -Iinclude -c -fdiagnostics-color -o ./test.o src/test.c
+ readelf -wi test.o
+ grep -E '/home/orion/debug-prefix-map-test/debug-prefix-map-test-1.0.0/run/dir1|some_name_not_likely_to_exist_in_path'
    <16>   DW_AT_comp_dir    : (indirect line string, offset: 0xb): /home/orion/debug-prefix-map-test/debug-prefix-map-test-1.0.0/run/dir1
+ readelf -wl test.o
+ grep -E '/home/orion/debug-prefix-map-test/debug-prefix-map-test-1.0.0/run/dir1|some_name_not_likely_to_exist_in_path'
  0     (indirect line string, offset: 0x52): /home/orion/debug-prefix-map-test/debug-prefix-map-test-1.0.0/run/dir1
+ cd -
/home/orion/debug-prefix-map-test/debug-prefix-map-test-1.0.0
+ exit 1

So in the directory directly under the symlink the mapping works.  But when in a subdirectory of it it does not.

On F37:

+ cd debug-prefix-map-test-1.0.0
+ for dir in run.real run.real/dir1
+ mkdir -p run.real/include run.real/src
+ rm -f run
+ ln -s run.real run
+ cd run
+ cat
+ cat
+ CCACHE_DISABLE=1
+ CCACHE_COMPILER=
+ CCACHE_PREFIX=
+ /usr/bin/gcc -g -fdebug-prefix-map=/builddir/build/BUILD/debug-prefix-map-test-1.0.0/run=some_name_not_likely_to_exist_in_path -Iinclude -c -fdiagnostics-color -o ./test.o src/test.c
+ readelf -wi test.o
+ grep -E '/builddir/build/BUILD/debug-prefix-map-test-1.0.0/run|some_name_not_likely_to_exist_in_path'
    <16>   DW_AT_comp_dir    : (indirect line string, offset: 0x0): some_name_not_likely_to_exist_in_path
+ readelf -wl test.o
+ grep -E '/builddir/build/BUILD/debug-prefix-map-test-1.0.0/run|some_name_not_likely_to_exist_in_path'
  0     (indirect line string, offset: 0x31): some_name_not_likely_to_exist_in_path
/builddir/build/BUILD/debug-prefix-map-test-1.0.0
+ cd -
+ for dir in run.real run.real/dir1
+ mkdir -p run.real/dir1/include run.real/dir1/src
+ rm -f run
+ ln -s run.real run
+ cd run/dir1
+ cat
+ cat
+ CCACHE_DISABLE=1
+ CCACHE_COMPILER=
+ CCACHE_PREFIX=
+ /usr/bin/gcc -g -fdebug-prefix-map=/builddir/build/BUILD/debug-prefix-map-test-1.0.0/run/dir1=some_name_not_likely_to_exist_in_path -Iinclude -c -fdiagnostics-color -o ./test.o src/test.c
+ readelf -wi test.o
+ grep -E '/builddir/build/BUILD/debug-prefix-map-test-1.0.0/run/dir1|some_name_not_likely_to_exist_in_path'
    <16>   DW_AT_comp_dir    : (indirect line string, offset: 0x0): some_name_not_likely_to_exist_in_path
+ readelf -wl test.o
+ grep -E '/builddir/build/BUILD/debug-prefix-map-test-1.0.0/run/dir1|some_name_not_likely_to_exist_in_path'
  0     (indirect line string, offset: 0x31): some_name_not_likely_to_exist_in_path
+ cd -
/builddir/build/BUILD/debug-prefix-map-test-1.0.0
+ exit 1
Comment 4 Ben Cotton 2023-02-07 15:05:51 UTC 
This bug appears to have been reported against 'rawhide' during the Fedora Linux 38 development cycle.
Changing version to 38.
Comment 5 Orion Poplawski 2023-03-22 02:27:11 UTC 
This appears to be fixed now.