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llvm-dwarfdump: Don't crash if DW_AT_{decl,call}_{file,line} uses sig…
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…ned form

The DWARF spec says:

 Any debugging information entry representing the declaration of an object,
 module, subprogram or type may have DW_AT_decl_file, DW_AT_decl_line and
 DW_AT_decl_column attributes, each of whose value is an unsigned integer
							 ^^^^^^^^
 constant.

If however, a producer happens to emit DW_AT_decl_file /
DW_AT_decl_line using a signed integer form, llvm-dwarfdump crashes,
like so:

     (... snip ...)
     0x000000b4:   DW_TAG_structure_type
                     DW_AT_name      ("test_struct")
                     DW_AT_byte_size (136)
                     DW_AT_decl_file (llvm-dwarfdump: (... snip ...)/llvm/include/llvm/ADT/Optional.h:197: T& llvm::optional_detail::OptionalStorage<T, true>::getValue() &
 [with T = long unsigned int]: Assertion `hasVal' failed.
     PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
     Stack dump:
     0.      Program arguments: /opt/rocm/llvm/bin/llvm-dwarfdump ./testsuite/outputs/gdb.rocm/lane-pc-vega20/lane-pc-vega20-kernel.so
      #0 0x000055cc8e78315f PrintStackTraceSignalHandler(void*) Signals.cpp:0:0
      #1 0x000055cc8e780d3d SignalHandler(int) Signals.cpp:0:0
      #2 0x00007f8f2cae8420 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x14420)
      #3 0x00007f8f2c58d00b raise /build/glibc-SzIz7B/glibc-2.31/signal/../sysdeps/unix/sysv/linux/raise.c:51:1
      llvm#4 0x00007f8f2c56c859 abort /build/glibc-SzIz7B/glibc-2.31/stdlib/abort.c:81:7
      llvm#5 0x00007f8f2c56c729 get_sysdep_segment_value /build/glibc-SzIz7B/glibc-2.31/intl/loadmsgcat.c:509:8
      llvm#6 0x00007f8f2c56c729 _nl_load_domain /build/glibc-SzIz7B/glibc-2.31/intl/loadmsgcat.c:970:34
      llvm#7 0x00007f8f2c57dfd6 (/lib/x86_64-linux-gnu/libc.so.6+0x33fd6)
      llvm#8 0x000055cc8e58ceb9 llvm::DWARFDie::dump(llvm::raw_ostream&, unsigned int, llvm::DIDumpOptions) const (/opt/rocm/llvm/bin/llvm-dwarfdump+0x2e0eb9)
      llvm#9 0x000055cc8e58bec3 llvm::DWARFDie::dump(llvm::raw_ostream&, unsigned int, llvm::DIDumpOptions) const (/opt/rocm/llvm/bin/llvm-dwarfdump+0x2dfec3)
     llvm#10 0x000055cc8e5b28a3 llvm::DWARFCompileUnit::dump(llvm::raw_ostream&, llvm::DIDumpOptions) (.part.21) DWARFCompileUnit.cpp:0:0

Likewise with DW_AT_call_file / DW_AT_call_line.

The problem is that the code in llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
dumping these attributes assumes that
FormValue.getAsUnsignedConstant() returns an armed optional.  If in
debug mode, we get an assertion line the above.  If in release mode,
and asserts are compiled out, then we proceed as if the optional had a
value, running into undefined behavior, printing whatever random
value.

Fix this by checking whether the optional returned by
FormValue.getAsUnsignedConstant() has a value, like done in other
places.

In addition, DWARFVerifier.cpp is validating DW_AT_call_file /
DW_AT_decl_file, but not AT_call_line / DW_AT_decl_line.  This commit
fixes that too.

The llvm-dwarfdump/X86/verify_file_encoding.yaml testcase is extended
to cover these cases.  Current llvm-dwarfdump crashes running the
newly-extended test.

"make check-llvm-tools-llvm-dwarfdump" shows no regressions, on x86-64
GNU/Linux.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D129392
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@palves @dwblaikie
palves authored and dwblaikie committed Jul 8, 2022
1 parent ca50840 commit ac6df7f
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Showing 3 changed files with 92 additions and 12 deletions.
30 changes: 19 additions & 11 deletions llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -136,23 +136,31 @@ static void dumpAttribute(raw_ostream &OS, const DWARFDie &Die,
auto Color = HighlightColor::Enumerator;
if (Attr == DW_AT_decl_file || Attr == DW_AT_call_file) {
Color = HighlightColor::String;
if (const auto *LT = U->getContext().getLineTableForUnit(U))
if (LT->getFileNameByIndex(
*FormValue.getAsUnsignedConstant(), U->getCompilationDir(),
DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, File)) {
File = '"' + File + '"';
Name = File;
if (const auto *LT = U->getContext().getLineTableForUnit(U)) {
if (Optional<uint64_t> Val = FormValue.getAsUnsignedConstant()) {
if (LT->getFileNameByIndex(
*Val, U->getCompilationDir(),
DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath,
File)) {
File = '"' + File + '"';
Name = File;
}
}
}
} else if (Optional<uint64_t> Val = FormValue.getAsUnsignedConstant())
Name = AttributeValueString(Attr, *Val);

if (!Name.empty())
WithColor(OS, Color) << Name;
else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line)
OS << *FormValue.getAsUnsignedConstant();
else if (Attr == DW_AT_low_pc &&
(FormValue.getAsAddress() ==
dwarf::computeTombstoneAddress(U->getAddressByteSize()))) {
else if (Attr == DW_AT_decl_line || Attr == DW_AT_call_line) {
if (Optional<uint64_t> Val = FormValue.getAsUnsignedConstant()) {
OS << *Val;
} else {
FormValue.dump(OS, DumpOpts);
}
} else if (Attr == DW_AT_low_pc &&
(FormValue.getAsAddress() ==
dwarf::computeTombstoneAddress(U->getAddressByteSize()))) {
if (DumpOpts.Verbose) {
FormValue.dump(OS, DumpOpts);
OS << " (";
Expand Down
8 changes: 8 additions & 0 deletions llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -704,6 +704,14 @@ unsigned DWARFVerifier::verifyDebugInfoAttribute(const DWARFDie &Die,
}
break;
}
case DW_AT_call_line:
case DW_AT_decl_line: {
if (!AttrValue.Value.getAsUnsignedConstant()) {
ReportError("DIE has " + AttributeString(Attr) +
" with invalid encoding");
}
break;
}
default:
break;
}
Expand Down
66 changes: 65 additions & 1 deletion llvm/test/tools/llvm-dwarfdump/X86/verify_file_encoding.yaml
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,42 @@
# CHECK-NEXT: DW_AT_high_pc [DW_FORM_data4] (0x00000100)
# CHECK-NEXT: DW_AT_call_file [DW_FORM_strp] ( .debug_str[0x00000012] = "")
# CHECK-NEXT: DW_AT_call_line [DW_FORM_data1] (10){{[[:space:]]}}
# CHECK-NEXT: error: DIE has DW_AT_decl_file with invalid encoding{{[[:space:]]}}
# CHECK-NEXT: 0x0000004a: DW_TAG_subprogram
# CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x0000001b] = "foo")
# CHECK-NEXT: DW_AT_low_pc [DW_FORM_addr] (0x0000000000002000)
# CHECK-NEXT: DW_AT_high_pc [DW_FORM_addr] (0x0000000000003000)
# CHECK-NEXT: DW_AT_decl_file [DW_FORM_sdata] (2)
# CHECK-NEXT: DW_AT_decl_line [DW_FORM_sdata] (3)
# CHECK-NEXT: DW_AT_call_file [DW_FORM_sdata] (4)
# CHECK-NEXT: DW_AT_call_line [DW_FORM_sdata] (5){{[[:space:]]}}
# CHECK-NEXT: error: DIE has DW_AT_decl_line with invalid encoding{{[[:space:]]}}
# CHECK-NEXT: 0x0000004a: DW_TAG_subprogram
# CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x0000001b] = "foo")
# CHECK-NEXT: DW_AT_low_pc [DW_FORM_addr] (0x0000000000002000)
# CHECK-NEXT: DW_AT_high_pc [DW_FORM_addr] (0x0000000000003000)
# CHECK-NEXT: DW_AT_decl_file [DW_FORM_sdata] (2)
# CHECK-NEXT: DW_AT_decl_line [DW_FORM_sdata] (3)
# CHECK-NEXT: DW_AT_call_file [DW_FORM_sdata] (4)
# CHECK-NEXT: DW_AT_call_line [DW_FORM_sdata] (5){{[[:space:]]}}
# CHECK-NEXT: error: DIE has DW_AT_call_file with invalid encoding{{[[:space:]]}}
# CHECK-NEXT: 0x0000004a: DW_TAG_subprogram
# CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x0000001b] = "foo")
# CHECK-NEXT: DW_AT_low_pc [DW_FORM_addr] (0x0000000000002000)
# CHECK-NEXT: DW_AT_high_pc [DW_FORM_addr] (0x0000000000003000)
# CHECK-NEXT: DW_AT_decl_file [DW_FORM_sdata] (2)
# CHECK-NEXT: DW_AT_decl_line [DW_FORM_sdata] (3)
# CHECK-NEXT: DW_AT_call_file [DW_FORM_sdata] (4)
# CHECK-NEXT: DW_AT_call_line [DW_FORM_sdata] (5){{[[:space:]]}}
# CHECK-NEXT: error: DIE has DW_AT_call_line with invalid encoding{{[[:space:]]}}
# CHECK-NEXT: 0x0000004a: DW_TAG_subprogram
# CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x0000001b] = "foo")
# CHECK-NEXT: DW_AT_low_pc [DW_FORM_addr] (0x0000000000002000)
# CHECK-NEXT: DW_AT_high_pc [DW_FORM_addr] (0x0000000000003000)
# CHECK-NEXT: DW_AT_decl_file [DW_FORM_sdata] (2)
# CHECK-NEXT: DW_AT_decl_line [DW_FORM_sdata] (3)
# CHECK-NEXT: DW_AT_call_file [DW_FORM_sdata] (4)
# CHECK-NEXT: DW_AT_call_line [DW_FORM_sdata] (5){{[[:space:]]}}

--- !ELF
FileHeader:
Expand All @@ -28,6 +64,7 @@ DWARF:
- main
- ''
- inline1
- foo
debug_abbrev:
- Table:
- Code: 0x0000000000000001
Expand Down Expand Up @@ -68,8 +105,26 @@ DWARF:
Form: DW_FORM_strp
- Attribute: DW_AT_call_line
Form: DW_FORM_data1
- Code: 0x0000000000000004
Tag: DW_TAG_subprogram
Children: DW_CHILDREN_no
Attributes:
- Attribute: DW_AT_name
Form: DW_FORM_strp
- Attribute: DW_AT_low_pc
Form: DW_FORM_addr
- Attribute: DW_AT_high_pc
Form: DW_FORM_addr
- Attribute: DW_AT_decl_file
Form: DW_FORM_sdata
- Attribute: DW_AT_decl_line
Form: DW_FORM_sdata
- Attribute: DW_AT_call_file
Form: DW_FORM_sdata
- Attribute: DW_AT_call_line
Form: DW_FORM_sdata
debug_info:
- Length: 0x0000000000000048
- Length: 0x0000000000000061
Version: 4
AbbrOffset: 0x0000000000000000
AddrSize: 8
Expand All @@ -93,6 +148,15 @@ DWARF:
- Value: 0x0000000000000100
- Value: 0x0000000000000012
- Value: 0x000000000000000A
- AbbrCode: 0x00000004
Values:
- Value: 0x000000000000001B
- Value: 0x0000000000002000
- Value: 0x0000000000003000
- Value: 0x0000000000000002
- Value: 0x0000000000000003
- Value: 0x0000000000000004
- Value: 0x0000000000000005
- AbbrCode: 0x00000000
Values: []
- AbbrCode: 0x00000000
Expand Down

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