Author: gclayton
Date: Tue May 31 17:29:56 2016
New Revision: 271343
URL: http://llvm.org/viewvc/llvm-project?rev=271343&view=rev
Log:
Add more verification on consectutive bitfields otherwise clang will assert.
We need to verify that consecutive bitfields have higher offsets and don't
overlap. The issues was found by running a broken version of recent clangs
where the bitfield offsets were being emitted incorrectly. To guard against
this we now verify and toss out any invalid bitfields and print a message that
indicates to file a bug against the compiler.
<rdar://problem/25737621>
Modified:
lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp?rev=271343&r1=271342&r2=271343&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
(original)
+++ lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp Tue May
31 17:29:56 2016
@@ -99,9 +99,9 @@ struct BitfieldInfo
uint64_t bit_size;
uint64_t bit_offset;
- BitfieldInfo () :
- bit_size (LLDB_INVALID_ADDRESS),
- bit_offset (LLDB_INVALID_ADDRESS)
+ BitfieldInfo() :
+ bit_size(LLDB_INVALID_ADDRESS),
+ bit_offset(LLDB_INVALID_ADDRESS)
{
}
@@ -112,10 +112,28 @@ struct BitfieldInfo
bit_offset = LLDB_INVALID_ADDRESS;
}
- bool IsValid ()
+ bool
+ IsValid() const
{
return (bit_size != LLDB_INVALID_ADDRESS) &&
- (bit_offset != LLDB_INVALID_ADDRESS);
+ (bit_offset != LLDB_INVALID_ADDRESS);
+ }
+
+ bool
+ NextBitfieldOffsetIsValid(const uint64_t next_bit_offset) const
+ {
+ if (IsValid())
+ {
+ // This bitfield info is valid, so any subsequent bitfields
+ // must not overlap and must be at a higher bit offset than
+ // any previous bitfield + size.
+ return (bit_size + bit_offset) <= next_bit_offset;
+ }
+ else
+ {
+ // If the this BitfieldInfo is not valid, then any offset isOK
+ return true;
+ }
}
};
@@ -2965,24 +2983,24 @@ DWARFASTParserClang::ParseChildMembers(c
{
this_field_info.bit_offset +=
byte_size * 8;
this_field_info.bit_offset -=
(bit_offset + bit_size);
-
- if (this_field_info.bit_offset >=
parent_bit_size)
- {
-
objfile->GetModule()->ReportWarning("0x%8.8" PRIx64 ": %s bitfield named \"%s\"
has invalid bit offset (0x%8.8" PRIx64 ") member will be ignored. Please file a
bug against the compiler and include the preprocessed output for %s\n",
-
die.GetID(),
-
DW_TAG_value_to_name(tag),
-
name,
-
this_field_info.bit_offset,
-
sc.comp_unit ? sc.comp_unit->GetPath().c_str() : "the source file");
- this_field_info.Clear();
- continue;
- }
}
else
{
this_field_info.bit_offset +=
bit_offset;
}
+ if ((this_field_info.bit_offset >=
parent_bit_size) ||
!last_field_info.NextBitfieldOffsetIsValid(this_field_info.bit_offset))
+ {
+
objfile->GetModule()->ReportWarning("0x%8.8" PRIx64 ": %s bitfield named \"%s\"
has invalid bit offset (0x%8.8" PRIx64 ") member will be ignored. Please file a
bug against the compiler and include the preprocessed output for %s\n",
+
die.GetID(),
+
DW_TAG_value_to_name(tag),
+
name,
+
this_field_info.bit_offset,
+
sc.comp_unit ? sc.comp_unit->GetPath().c_str() : "the source file");
+ this_field_info.Clear();
+ continue;
+ }
+
// Update the field bit offset we will
report for layout
field_bit_offset =
this_field_info.bit_offset;
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