[llvm-dwarfdump] - Teach tool about few GNU call_sites constants.

[grimar]

Summary

This teaches tool about following consants: DW_TAG_GNU_call_site, DW_TAG_GNU_call_site_parameter,
DW_AT_GNU_call_site_value, DW_AT_GNU_all_call_sites.

We faced them during investigation of objects produced by GCC in PR34852.
Constants documented here: https://sourceware.org/elfutils/DwarfExtensions

[grimar]

• Updated to dump DW_AT_GNU_call_site_value exprloc.

[aprantl]

Could you also teach the DWARFVerifier about these attributes?
You might also want to add support for the standardized DWARF 5 version of DW_AT_call_site & friends.

[grimar]

In D39119#902232, @aprantl wrote:

Could you also teach the DWARFVerifier about these attributes?

Will take a look.

You might also want to add support for the standardized DWARF 5 version of DW_AT_call_site & friends.

I see Dwarf.def file already contains something about this:

HANDLE_DW_TAG(0x0048, call_site, 5, DWARF)
HANDLE_DW_TAG(0x0049, call_site_parameter, 5, DWARF)

I'll take a look if something is missing there.

Thanks !

[grimar]

In D39119#902232, @aprantl wrote:

Could you also teach the DWARFVerifier about these attributes?

I committed cleanup for testcase (rL316428). Now it passes -verify without errors.

And tried to investigate what can be needed for DWARFVerifier.
This attributes has following forms:

1. DW_AT_GNU_all_call_sites, DW_FORM_flag_present
2. DW_AT_GNU_call_site_value, DW_FORM_exprloc

First one seems does not need anything. DW_FORM_exprloc seems
need some verification, but DW_AT_GNU_call_site_value is already proccessed here (implemented in current patch):
https://github.com/llvm-mirror/llvm/blob/master/lib/DebugInfo/DWARF/DWARFDie.cpp#L238
together with another location expressions. And errors are reported:
https://github.com/llvm-mirror/llvm/blob/master/lib/DebugInfo/DWARF/DWARFExpression.cpp#L259.

Though that happens with -v and not with -verify for some reason. So if I break the expression,
with verbose option I get:

DW_AT_GNU_call_site_value [DW_FORM_exprloc] (DW_OP_lit4, decoding error. 00 00 00 00 00)

But with -verify it reports no any errors. Is it correct ? I would expect verify to report failture.
Its unrelative to my changes though.

Aside from this issue with DW_FORM_exprloc above, It seems nothing else should be done for
these 2 GNU all_call_sites attributes on DWARFVerifier side, am I right ? Should I check something else here ?

[aprantl]

In D39119#905051, @grimar wrote:

In D39119#902232, @aprantl wrote:

Could you also teach the DWARFVerifier about these attributes?

I committed cleanup for testcase (rL316428). Now it passes -verify without errors.

And tried to investigate what can be needed for DWARFVerifier.
This attributes has following forms:

1. DW_AT_GNU_all_call_sites, DW_FORM_flag_present
2. DW_AT_GNU_call_site_value, DW_FORM_exprloc

First one seems does not need anything. DW_FORM_exprloc seems
need some verification, but DW_AT_GNU_call_site_value is already proccessed here (implemented in current patch):
https://github.com/llvm-mirror/llvm/blob/master/lib/DebugInfo/DWARF/DWARFDie.cpp#L238
together with another location expressions. And errors are reported:
https://github.com/llvm-mirror/llvm/blob/master/lib/DebugInfo/DWARF/DWARFExpression.cpp#L259.

Though that happens with -v and not with -verify for some reason. So if I break the expression,
with verbose option I get:

DW_AT_GNU_call_site_value [DW_FORM_exprloc] (DW_OP_lit4, decoding error. 00 00 00 00 00)

But with -verify it reports no any errors. Is it correct ? I would expect verify to report failture.
Its unrelative to my changes though.

Aside from this issue with DW_FORM_exprloc above, It seems nothing else should be done for
these 2 GNU all_call_sites attributes on DWARFVerifier side, am I right ? Should I check something else here ?

@JDevlieghere: could you perhaps help @grimar to figure out what is missing here?

[JDevlieghere]

In D39119#905245, @aprantl wrote:

@JDevlieghere: could you perhaps help @grimar to figure out what is missing here?

The verifier currently doesn't consider DWARF expressions. I think this should be fairly easy to extend: just iterate over its iterations (as the print function does) and check DWARFExpression::Operation::isError().

include/llvm/BinaryFormat/Dwarf.def

 // Vendor extensions:
 HANDLE_DW_TAG(0x4081, MIPS_loop, 0, MIPS)
 HANDLE_DW_TAG(0x4101, format_label, 0, GNU)
 HANDLE_DW_TAG(0x4102, function_template, 0, GNU)
 HANDLE_DW_TAG(0x4103, class_template, 0, GNU)
 HANDLE_DW_TAG(0x4106, GNU_template_template_param, 0, GNU)
 HANDLE_DW_TAG(0x4107, GNU_template_parameter_pack, 0, GNU)
 HANDLE_DW_TAG(0x4108, GNU_formal_parameter_pack, 0, GNU)
+HANDLE_DW_TAG(0x4109, GNU_call_site, 0, GNU)
+HANDLE_DW_TAG(0x410a, GNU_call_site_parameter, 0, GNU)
 HANDLE_DW_TAG(0x4200, APPLE_property, 0, APPLE)
 HANDLE_DW_TAG(0xb000, BORLAND_property, 0, BORLAND)
 HANDLE_DW_TAG(0xb001, BORLAND_Delphi_string, 0, BORLAND)
 HANDLE_DW_TAG(0xb002, BORLAND_Delphi_dynamic_array, 0, BORLAND)
 HANDLE_DW_TAG(0xb003, BORLAND_Delphi_set, 0, BORLAND)
 HANDLE_DW_TAG(0xb004, BORLAND_Delphi_variant, 0, BORLAND)
 
 // Attributes.

 HANDLE_DW_AT(0x2102, src_info, 0, GNU)
 HANDLE_DW_AT(0x2103, mac_info, 0, GNU)
 HANDLE_DW_AT(0x2104, src_coords, 0, GNU)
 HANDLE_DW_AT(0x2105, body_begin, 0, GNU)
 HANDLE_DW_AT(0x2106, body_end, 0, GNU)
 HANDLE_DW_AT(0x2107, GNU_vector, 0, GNU)
 HANDLE_DW_AT(0x2110, GNU_template_name, 0, GNU)
 HANDLE_DW_AT(0x210f, GNU_odr_signature, 0, GNU)
+HANDLE_DW_AT(0x2111, GNU_call_site_value, 0, GNU)
+HANDLE_DW_AT(0x2117, GNU_all_call_sites, 0, GNU)
 HANDLE_DW_AT(0x2119, GNU_macros, 0, GNU)
 // Extensions for Fission proposal.
 HANDLE_DW_AT(0x2130, GNU_dwo_name, 0, GNU)
 HANDLE_DW_AT(0x2131, GNU_dwo_id, 0, GNU)
 HANDLE_DW_AT(0x2132, GNU_ranges_base, 0, GNU)
 HANDLE_DW_AT(0x2133, GNU_addr_base, 0, GNU)
 HANDLE_DW_AT(0x2134, GNU_pubnames, 0, GNU)
 HANDLE_DW_AT(0x2135, GNU_pubtypes, 0, GNU)

test/tools/llvm-dwarfdump/X86/gnu_call_site.s

+# RUN: llvm-mc %s -filetype obj -triple i686-pc-linux -o %t
+# RUN: llvm-dwarfdump %t | FileCheck %s
+
+# CHECK:      DW_TAG_subprogram
+# CHECK-NEXT:   DW_AT_external  (true)
+# CHECK-NEXT:   DW_AT_name      ("fn4")
+# CHECK-NEXT:   DW_AT_linkage_name      ()
+# CHECK-NEXT:   DW_AT_low_pc    (0x0000000000000000)
+# CHECK-NEXT:   DW_AT_high_pc   (0x00000000)
+# CHECK-NEXT:   DW_AT_frame_base        (DW_OP_call_frame_cfa)
+# CHECK-NEXT:   DW_AT_GNU_all_call_sites        (true)
+
+# CHECK:      DW_TAG_GNU_call_site
+# CHECK-NEXT:   DW_AT_low_pc  (0x0000000000000000)
+# CHECK-NEXT:   DW_AT_abstract_origin (cu + 0x0001)
+
+# CHECK:      DW_TAG_GNU_call_site_parameter
+# CHECK-NEXT:   DW_AT_location      (DW_OP_reg0 EAX)
+# CHECK-NEXT:   DW_AT_GNU_call_site_value   (<0x5> 03 00 00 00 00 )
+
+.section  .debug_info,"",@progbits
+  .long  0x47
+  .value  0x4
+  .long  0
+  .byte  0x4
+
+  .uleb128 0x1 # DW_TAG_compile_unit [1]
+  .long  0
+  .byte  0x0
+  .long  0
+  .long  0
+  .long  0
+  .long  0
+  .long  0
+
+  .uleb128 0xe # DW_TAG_subprogram [14]
+  .string  "fn4"
+  .long  0
+  .long  0
+  .long  0
+  .uleb128 0x1  # DW_AT_GNU_all_call_sites
+  .byte  0x9c
+
+  .uleb128 0x12 # DW_TAG_GNU_call_site [18]
+  .long  0x0
+  .long  0x1
+
+  .uleb128 0x13 # DW_TAG_GNU_call_site_parameter [19]
+  .uleb128 0x1
+  .byte  0x50
+  .uleb128 0x5
+  .byte  0x3
+  .long  X
+  .byte  0
+  .byte  0
+  .byte  0
+
+.section .debug_abbrev,"",@progbits
+  .uleb128 0x1
+  .uleb128 0x11
+  .byte  0x1 # [1]
+  .uleb128 0x25
+  .uleb128 0xe
+  .uleb128 0x13
+  .uleb128 0xb
+  .uleb128 0x3
+  .uleb128 0xe
+  .uleb128 0x1b
+  .uleb128 0xe
+  .uleb128 0x11
+  .uleb128 0x1
+  .uleb128 0x12
+  .uleb128 0x6
+  .uleb128 0x10
+  .uleb128 0x17
+  .byte  0
+  .byte  0
+
+  .uleb128 0xe # [14]
+  .uleb128 0x2e
+  .byte  0x1
+  .uleb128 0x3f
+  .uleb128 0x19
+  .uleb128 0x3
+  .uleb128 0x8
+  .uleb128 0x6e
+  .uleb128 0xe
+  .uleb128 0x11
+  .uleb128 0x1
+  .uleb128 0x12
+  .uleb128 0x6
+  .uleb128 0x40
+  .uleb128 0x18
+  .uleb128 0x2117
+  .uleb128 0x19
+  .byte  0
+  .byte  0
+
+  .uleb128 0x12 # [18]
+  .uleb128 0x4109
+  .byte  0x1
+  .uleb128 0x11
+  .uleb128 0x1
+  .uleb128 0x31
+  .uleb128 0x13
+  .byte  0
+  .byte  0
+
+  .uleb128 0x13 # [19]
+  .uleb128 0x410a
+  .byte  0
+  .uleb128 0x2
+  .uleb128 0x18
+  .uleb128 0x2111
+  .uleb128 0x18
+  .byte  0
+  .byte  0
+  .byte  0