[Bug translator/31028] New: Systemtap doesn't find probe points for process.function("*").callee("*")' in code with DWARF5 debuginfo

[Bug translator/31028] New: Systemtap doesn't find probe points for process.function("*").callee("*")' in code with DWARF5 debuginfo

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31028

            Bug ID: 31028
           Summary: Systemtap doesn't find probe points for
                    process.function("*").callee("*")' in code with DWARF5
                    debuginfo
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: translator
          Assignee: systemtap at sourceware dot org
          Reporter: wcohen at redhat dot com
  Target Milestone: ---

When reviewing the systemtap "make install" test results there were and
excessive number of failures for the systemtap.base/listing_mode.exp on RHEL9,
Fedora 38, and rawhide, about 200 failure on x86_64 machines.  this can be
reproduced with:

sudo make installcheck RUNTESTFLAGS="-debug systemtap.base/listing_mode.exp"

The issues are with the .callee()

There are fewer failures on RHEL8 machine.  When comparing the code being
instrumented I found that RHEL 8 is using DWARF4 and the tests with the high
failure rate are using DWARF5. Can narrow the reproducer down to following:

 gcc  /usr/share/systemtap/testsuite/systemtap.base/listing_mode.c  
-isystem/usr/share/systemtap/testsuite -isystem/usr/include -g -O -fPIC -shared
-DLISTING_MODE_LIB  -lm  -o liblisting_mode.so
 gcc  /usr/share/systemtap/testsuite/systemtap.base/listing_mode.c  
-isystem/usr/share/systemtap/testsuite -isystem/usr/include -g -O
-llisting_mode -Wl,-rpath,/usr/share/systemtap/testsuite -L.
-DLISTING_MODE_MAIN  -lm  -o listing_mode  

 stap -l 'process.function("foo").callee("bar")'  -c listing_mode

On RHEL8 get the expected output:

process("/home/wcohen/systemtap_write/systemtap/listing_mode").function("foo@/usr/share/systemtap/testsuite/systemtap.base/listing_mode.c:23").callee("bar@/usr/share/systemtap/testsuite/systemtap.base/listing_mode.c:16")

On RHEL9/fedora38/rawhide get nothing.

Comparing the llvm-dwarfdump output for listing_mode on RHEL8 see:

0x000003f6:     DW_TAG_GNU_call_site
                  DW_AT_low_pc  (0x0000000000400711)
                  DW_AT_abstract_origin (0x0000040c "bar")

0x00000403:       DW_TAG_GNU_call_site_parameter
                    DW_AT_location      (DW_OP_reg5 RDI)
                    DW_AT_GNU_call_site_value  
(DW_OP_GNU_entry_value(DW_OP_reg5 RDI))

On Fedora 38 the dwarf 5 call site information is a little different:

0x00000188:     DW_TAG_call_site
                  DW_AT_call_return_pc  (0x0000000000401182)
                  DW_AT_call_origin     (0x0000019e)

0x00000195:       DW_TAG_call_site_parameter
                    DW_AT_location      (DW_OP_reg5 RDI)
                    DW_AT_call_value    (DW_OP_entry_value(DW_OP_reg5 RDI))

Appears:
DWARF4 -> DWARF5
DW_AT_low_pc -> DW_AT_call_return_pc
DW_AT_abstract_origin -> DW_AT_call_origin

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[Bug translator/31028] Systemtap doesn't find probe points for process.function("*").callee("*")' in code with DWARF5 debuginfo

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31028

--- Comment #1 from William Cohen <wcohen at redhat dot com> ---
Created attachment 15206
  --> https://sourceware.org/bugzilla/attachment.cgi?id=15206&action=edit
WIP patch to add dwarf5 callee support

This is a non-working patch attempting to add the dwarf5 callee support.

It has changes in the general area expected for the callee checks, but does not
currently provide any expected matches with the simple:

 stap -l 'process.function("foo").callee("bar")'  -c listing_mode

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[Bug translator/31028] Systemtap doesn't find probe points for process.function("*").callee("*")' in code with DWARF5 debuginfo

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31028

--- Comment #2 from William Cohen <wcohen at redhat dot com> ---
Created attachment 15207
  --> https://sourceware.org/bugzilla/attachment.cgi?id=15207&action=edit
This patch appears to address the problem on f38 and works on rhel8

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[Bug translator/31028] Systemtap doesn't find probe points for process.function("*").callee("*")' in code with DWARF5 debuginfo

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31028

William Cohen <wcohen at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #3 from William Cohen <wcohen at redhat dot com> ---
This should be resolved git commit e72dc118e563c645d93a1a2d771e8d90e8fec1ae. 
After the commit the systemtap.base/listing_mode.exp test results are much
better:

sudo make installcheck RUNTESTFLAGS="systemtap.base/listing_mode.exp"
....
                === systemtap Summary ===

# of expected passes            1701
# of known failures             32

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