[Lldb-commits] [lldb] r142897 - /lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

[Greg Clayton]

Author: gclayton
Date: Mon Oct 24 20:25:35 2011
New Revision: 142897

URL: http://llvm.org/viewvc/llvm-project?rev=142897&view=rev
Log:
<rdar://problem/10335756>

Fixed an issue where bad DWARF from clang would get recycled from DWARF back
into types and cause clang to assert and die, killing the lldb binary, when
it tried to used the type in an expression.


Modified:
    lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp?rev=142897&r1=142896&r2=142897&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp (original)
+++ lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp Mon Oct 24 20:25:35 2011
@@ -1348,8 +1348,27 @@
                         }
                     }
                     
-                    // FIXME: Make Clang ignore Objective-C accessibility for expressions
+                    // Clang has a DWARF generation bug where sometimes it 
+                    // represents fields that are references with bad byte size
+                    // and bit size/offset information such as:
+                    //
+                    //  DW_AT_byte_size( 0x00 )
+                    //  DW_AT_bit_size( 0x40 )
+                    //  DW_AT_bit_offset( 0xffffffffffffffc0 )
+                    //
+                    // So check the bit offset to make sure it is sane, and if 
+                    // the values are not sane, remove them. If we don't do this
+                    // then we will end up with a crash if we try to use this 
+                    // type in an expression when clang becomes unhappy with its
+                    // recycled debug info.
                     
+                    if (bit_offset > 128)
+                    {
+                        bit_size = 0;
+                        bit_offset = 0;
+                    }
+
+                    // FIXME: Make Clang ignore Objective-C accessibility for expressions
                     if (class_language == eLanguageTypeObjC ||
                         class_language == eLanguageTypeObjC_plus_plus)
                         accessibility = eAccessNone;