DWARFVerifier: Check "completeness" of .debug_names section

Summary:
This patch implements a check which makes sure all entries required by
the DWARF v5 specification are present in the Name Index. The algorithm
tries to follow the wording of Section 6.1.1.1 of the spec as closely as
possible.

The main deviation from it is that instead of a whitelist-based approach
in the spec "The name index must contain an entry for each debugging
information entry that defines a named subprogram, label, variable,
type, or namespace" I chose a blacklist-based one, where I consider
everything to be "in" and then remove the entries that don't make sense.
I did this because it has more potential for catching interesting cases
and the above is a bit vague (it uses plain words like "variable" and
"subprogram", but the rest of the section speaks about specific TAGs).

This approach has raised some interesting questions, the main one being
whether enumerator values should be indexed. The consensus seems to be
that they should, although it does not follow from section 6.1.1.1.
For the time being I made the verifier ignore these, as LLVM does not do
this yet, and I wanted to get a clean run when verifying generated debug
info.

Another interesting case was the DW_TAG_imported_declaration. It was not
immediately clear to me whether this should go in or not, but currently
it is not indexed, and (unlike the enumerators) in does not seem to cause
problems for LLDB, so I've also ignored it.

Reviewers: JDevlieghere, aprantl, dblaikie

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D46583

llvm-svn: 331868

1 files changed, 195 insertions, 0 deletions

diff --git a/llvm/test/tools/llvm-dwarfdump/X86/debug-names-verify-completeness.s b/llvm/test/tools/llvm-dwarfdump/X86/debug-names-verify-completeness.s
new file mode 100644
index 00000000000..359dce9b0b9
--- /dev/null
+++ b/llvm/test/tools/llvm-dwarfdump/X86/debug-names-verify-completeness.s
@@ -0,0 +1,195 @@
+# RUN: llvm-mc -triple x86_64-pc-linux %s -filetype=obj -o - | not llvm-dwarfdump -verify - | FileCheck %s
+
+# CHECK: error: Name Index @ 0x0: Entry for DIE @ 0x10 (DW_TAG_namespace) with name namesp missing.
+# CHECK: error: Name Index @ 0x0: Entry for DIE @ 0x15 (DW_TAG_variable) with name var_block_addr missing.
+# CHECK: error: Name Index @ 0x0: Entry for DIE @ 0x25 (DW_TAG_namespace) with name (anonymous namespace) missing.
+# CHECK: error: Name Index @ 0x0: Entry for DIE @ 0x26 (DW_TAG_variable) with name var_loc_addr missing.
+# CHECK: error: Name Index @ 0x0: Entry for DIE @ 0x30 (DW_TAG_variable) with name var_loc_tls missing.
+# CHECK: error: Name Index @ 0x0: Entry for DIE @ 0x37 (DW_TAG_variable) with name var_loc_gnu_tls missing.
+# CHECK: error: Name Index @ 0x0: Entry for DIE @ 0x3e (DW_TAG_subprogram) with name fun_name missing.
+# CHECK: error: Name Index @ 0x0: Entry for DIE @ 0x3e (DW_TAG_subprogram) with name _Z8fun_name missing.
+# CHECK: error: Name Index @ 0x0: Entry for DIE @ 0x4f (DW_TAG_inlined_subroutine) with name fun_inline missing.
+# CHECK: error: Name Index @ 0x0: Entry for DIE @ 0x64 (DW_TAG_label) with name label missing.
+
+	.section	.debug_str,"MS",@progbits,1
+.Linfo_producer:
+	.asciz	"hand-written DWARF"
+.Lname_var_block_addr:
+	.asciz	"var_block_addr"
+.Lname_var_loc_addr:
+	.asciz	"var_loc_addr"
+.Lname_var_loc_tls:
+	.asciz	"var_loc_tls"
+.Lname_var_loc_gnu_tls:
+	.asciz	"var_loc_gnu_tls"
+.Lname_fun_name:
+	.asciz	"fun_name"
+.Lname_fun_link_name:
+	.asciz	"_Z8fun_name"
+.Lname_fun_inline:
+	.asciz	"fun_inline"
+.Lnamespace:
+	.asciz	"namesp"
+.Lname_label:
+	.asciz	"label"
+
+	.section	.debug_loc,"",@progbits
+.Ldebug_loc0:
+	.quad	0
+	.quad	1
+	.short	.Lloc0_end-.Lloc0_start # Loc expr size
+.Lloc0_start:
+	.byte	3                       # DW_OP_addr
+        .quad 0x47
+.Lloc0_end:
+	.quad	0
+	.quad	0
+
+	.section	.debug_abbrev,"",@progbits
+	.byte	1                       # Abbreviation Code
+	.byte	17                      # DW_TAG_compile_unit
+	.byte	1                       # DW_CHILDREN_yes
+	.byte	37                      # DW_AT_producer
+	.byte	14                      # DW_FORM_strp
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+
+	.byte	2                       # Abbreviation Code
+	.byte	52                      # DW_TAG_variable
+	.byte	0                       # DW_CHILDREN_no
+	.byte	3                       # DW_AT_name
+	.byte	14                      # DW_FORM_strp
+	.byte	2                       # DW_AT_location
+	.byte	24                      # DW_FORM_exprloc
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+
+	.byte	3                       # Abbreviation Code
+	.byte	46                      # DW_TAG_subprogram
+	.byte	1                       # DW_CHILDREN_yes
+	.byte	3                       # DW_AT_name
+	.byte	14                      # DW_FORM_strp
+	.byte	110                     # DW_AT_linkage_name
+	.byte	14                      # DW_FORM_strp
+	.byte	82                      # DW_AT_entry_pc
+	.byte	1                       # DW_FORM_addr
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+
+	.byte	4                       # Abbreviation Code
+	.byte	57                      # DW_TAG_namespace
+	.byte	1                       # DW_CHILDREN_yes
+	.byte	3                       # DW_AT_name
+	.byte	14                      # DW_FORM_strp
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+
+	.byte	5                       # Abbreviation Code
+	.byte	52                      # DW_TAG_variable
+	.byte	0                       # DW_CHILDREN_no
+	.byte	3                       # DW_AT_name
+	.byte	14                      # DW_FORM_strp
+	.byte	2                       # DW_AT_location
+	.byte	23                      # DW_FORM_sec_offset
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+
+	.byte	6                       # Abbreviation Code
+	.byte	57                      # DW_TAG_namespace
+	.byte	1                       # DW_CHILDREN_yes
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+
+	.byte	7                       # Abbreviation Code
+	.byte	29                      # DW_TAG_inlined_subroutine
+	.byte	0                       # DW_CHILDREN_no
+	.byte	3                       # DW_AT_name
+	.byte	14                      # DW_FORM_strp
+	.byte	17                      # DW_AT_low_pc
+	.byte	1                       # DW_FORM_addr
+	.byte	18                      # DW_AT_high_pc
+	.byte	1                       # DW_FORM_addr
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+
+	.byte	8                       # Abbreviation Code
+	.byte	10                      # DW_TAG_label
+	.byte	0                       # DW_CHILDREN_no
+	.byte	3                       # DW_AT_name
+	.byte	14                      # DW_FORM_strp
+	.byte	82                      # DW_AT_entry_pc
+	.byte	1                       # DW_FORM_addr
+	.byte	0                       # EOM(1)
+	.byte	0                       # EOM(2)
+
+	.byte	0                       # EOM(3)
+	.section	.debug_info,"",@progbits
+.Lcu_begin0:
+	.long	.Lcu_end0-.Lcu_start0   # Length of Unit
+.Lcu_start0:
+	.short	4                       # DWARF version number
+	.long	.debug_abbrev           # Offset Into Abbrev. Section
+	.byte	8                       # Address Size (in bytes)
+	.byte	1                       # Abbrev [1] DW_TAG_compile_unit
+	.long	.Linfo_producer         # DW_AT_producer
+
+	.byte	4                       # Abbrev [4] DW_TAG_namespace
+	.long	.Lnamespace             # DW_AT_name
+	.byte	2                       # Abbrev [2] DW_TAG_variable
+	.long	.Lname_var_block_addr   # DW_AT_name
+	.byte	9                       # DW_AT_location
+	.byte	3                       # DW_OP_addr
+	.quad	0x47
+	.byte	0                       # End Of Children Mark
+
+	.byte	6                       # Abbrev [6] DW_TAG_namespace
+	.byte	5                       # Abbrev [5] DW_TAG_variable
+	.long	.Lname_var_loc_addr     # DW_AT_name
+	.long	.Ldebug_loc0            # DW_AT_location
+	.byte	0                       # End Of Children Mark
+
+	.byte	2                       # Abbrev [2] DW_TAG_variable
+	.long	.Lname_var_loc_tls      # DW_AT_name
+	.byte	1                       # DW_AT_location
+	.byte	0x9b                    # DW_OP_form_tls_address
+
+	.byte	2                       # Abbrev [2] DW_TAG_variable
+	.long	.Lname_var_loc_gnu_tls  # DW_AT_name
+	.byte	1                       # DW_AT_location
+	.byte	0xe0                    # DW_OP_GNU_push_tls_address
+
+	.byte	3                       # Abbrev [3] DW_TAG_subprogram
+	.long	.Lname_fun_name         # DW_AT_name
+	.long	.Lname_fun_link_name    # DW_AT_linkage_name
+	.quad	0x47                    # DW_AT_entry_pc
+	.byte	7                       # Abbrev [7] DW_TAG_inlined_subroutine
+	.long	.Lname_fun_inline       # DW_AT_name
+	.quad	0x48                    # DW_AT_low_pc
+	.quad	0x49                    # DW_AT_high_pc
+	.byte	8                       # Abbrev [8] DW_TAG_label
+	.long	.Lname_label            # DW_AT_name
+	.quad	0x4a                    # DW_AT_entry_pc
+	.byte	0                       # End Of Children Mark
+
+	.byte	0                       # End Of Children Mark
+.Lcu_end0:
+
+	.section	.debug_names,"",@progbits
+	.long	.Lnames_end0-.Lnames_start0 # Header: contribution length
+.Lnames_start0:
+	.short	5                       # Header: version
+	.short	0                       # Header: padding
+	.long	1                       # Header: compilation unit count
+	.long	0                       # Header: local type unit count
+	.long	0                       # Header: foreign type unit count
+	.long	0                       # Header: bucket count
+	.long	0                       # Header: name count
+	.long	.Lnames_abbrev_end0-.Lnames_abbrev_start0 # Header: abbreviation table size
+	.long	0                       # Header: augmentation length
+	.long	.Lcu_begin0             # Compilation unit 0
+.Lnames_abbrev_start0:
+	.byte	0                       # End of abbrev list
+.Lnames_abbrev_end0:
+.Lnames_entries0:
+.Lnames_end0:
+