[Bug tools/29150] New: Would be useful to have a filter in eu-readelf like --name=

[mark at klomp dot org via Elfutils-devel]

https://sourceware.org/bugzilla/show_bug.cgi?id=29150

Bug ID: 29150
   Summary: Would be useful to have a filter in eu-readelf like
--name=
   Product: elfutils
   Version: unspecified
Status: NEW
  Severity: normal
  Priority: P2
 Component: tools
  Assignee: unassigned at sourceware dot org
  Reporter: mark at klomp dot org
CC: elfutils-devel at sourceware dot org
  Target Milestone: ---

Copied from https://bugzilla.redhat.com/show_bug.cgi?id=1980026

For large executables like the linux kernel the human readable output of
eu-readelf could be in the gigabytes.  llvm-dwarfdump has --name=
that allows the output to be limited to just DIEs with that symbol name.  So to
see the DIEs and their children (-c) of function trace_event_name for kernel
can do the following which is about 40K of output:

llvm-dwarfdump  -c --name=trace_event_name
/usr/lib/debug/lib/modules/5.12.7-300.fc34.x86_64/vmlinux >
trace_event_name.dwarf

Much easier to inspect 40KB of text than 4.8GB of the entire output from
llvm-dwarfdump.  Would be nice if eu-readelf had similar filter for
--debug-dump=info and ability to select whether to print children DIEs.

Documentation about the llvm-dwarfdump options is at
https://llvm.org/docs/CommandGuide/llvm-dwarfdump.html .

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[PATCH] libdwfl: Update docs and nonnull attributes for dwfl_module_addrinfo

[Mark Wielaard]

Make clear that both the offset and sym arguments cannot be NULL.

https://bugzilla.redhat.com/show_bug.cgi?id=1986555

Signed-off-by: Mark Wielaard 
---
 libdwfl/ChangeLog |  5 +
 libdwfl/libdwfl.h | 32 
 2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 76053039..b3ca56cb 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,8 @@
+2022-05-15  Mark Wielaard  
+
+   * libdwfl.h (dwfl_module_addrinfo): Update docs and nonnull
+   attribute to make clear offset and sym cannot be NULL.
+
 2022-04-22  Mark Wielaard  
 
* debuginfod-client.c (init_control): New static pthread_once_t.
diff --git a/libdwfl/libdwfl.h b/libdwfl/libdwfl.h
index f98f1d52..c55a8eaa 100644
--- a/libdwfl/libdwfl.h
+++ b/libdwfl/libdwfl.h
@@ -473,26 +473,26 @@ extern const char *dwfl_module_addrname (Dwfl_Module 
*mod, GElf_Addr address);
when nothing was found.  If the architecture uses function
descriptors, and symbol st_value points to one, ADDRESS will be
matched against either the adjusted st_value or the associated
-   function entry value as described in dwfl_module_getsym_info.  If
-   OFFSET is not NULL it will be filled in with the difference from
-   the start of the symbol (or function entry).  If SYM is not NULL it
-   is filled in with the symbol associated with the matched ADDRESS.
-   The SYM->ST_VALUE itself isn't adjusted in any way.  Fills in ELFP,
-   if not NULL, with the ELF file the symbol originally came from.
-   Note that symbols can come from either the main, debug or auxiliary
-   ELF symbol file (either dynsym or symtab).  If SHNDXP is non-null,
-   it's set with the section index (whether from st_shndx or extended
-   index table).  Fills in BIAS, if not NULL, with the difference
-   between addresses within the loaded module and those in symbol
-   table of the ELF file.  Note that the address matched against the
-   symbol might be in a different section than the returned symbol.
-   The section in the main elf file in ADDRESS falls can be found with
-   dwfl_module_address_section.  */
+   function entry value as described in dwfl_module_getsym_info.
+   OFFSET will be filled in with the difference from the start of the
+   symbol (or function entry), OFFSET cannot be NULL.  SYM is filled
+   in with the symbol associated with the matched ADDRESS, SYM cannot
+   be NULL.  The SYM->ST_VALUE itself isn't adjusted in any way.
+   Fills in ELFP, if not NULL, with the ELF file the symbol originally
+   came from.  Note that symbols can come from either the main, debug
+   or auxiliary ELF symbol file (either dynsym or symtab).  If SHNDXP
+   is non-null, it's set with the section index (whether from st_shndx
+   or extended index table).  Fills in BIAS, if not NULL, with the
+   difference between addresses within the loaded module and those in
+   symbol table of the ELF file.  Note that the address matched
+   against the symbol might be in a different section than the
+   returned symbol.  The section in the main elf file in ADDRESS falls
+   can be found with dwfl_module_address_section.  */
 extern const char *dwfl_module_addrinfo (Dwfl_Module *mod, GElf_Addr address,
 GElf_Off *offset, GElf_Sym *sym,
 GElf_Word *shndxp, Elf **elfp,
 Dwarf_Addr *bias)
-  __nonnull_attribute__ (3);
+  __nonnull_attribute__ (3, 4);
 
 /* Find the symbol that ADDRESS lies inside, and return detailed
information as for dwfl_module_getsym (above).  Note that like
-- 
2.30.2