Fix LLDB crash accessing unknown DW_FORM_* attributes

Current LLDB (that is without DWZ support) crashes accessing Fedora debug info:
READ of size 8 at 0x60200000ffc8 thread T0
    #0 in DWARFDebugInfoEntry::BuildAddressRangeTable(SymbolFileDWARF*, DWARFCompileUnit const*, DWARFDebugAranges*) const tools/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp:1336

Greg Clayton: We will need a warning to be emitted in
SymbolFileDWARF::CalculateAbilities() stating we won't parse the DWARF due to
"unsupported DW_FORM value of 0x1f20".

Patch has been mostly written by Greg Clayton.

Differential revision: https://reviews.llvm.org/D35622

llvm-svn: 309581

1 files changed, 24 insertions, 0 deletions

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugAbbrev.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugAbbrev.cpp
index d681925daea..1cf0e7eeeb6 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugAbbrev.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugAbbrev.cpp
@@ -98,6 +98,21 @@ dw_uleb128_t DWARFAbbreviationDeclarationSet::AppendAbbrevDeclSequential(
 }
 
 //----------------------------------------------------------------------
+// DWARFAbbreviationDeclarationSet::GetUnsupportedForms()
+//----------------------------------------------------------------------
+void DWARFAbbreviationDeclarationSet::GetUnsupportedForms(
+    std::set<dw_form_t> &invalid_forms) const {
+  for (const auto &abbr_decl : m_decls) {
+    const size_t num_attrs = abbr_decl.NumAttributes();
+    for (size_t i=0; i<num_attrs; ++i) {
+      dw_form_t form = abbr_decl.GetFormByIndex(i);
+      if (!DWARFFormValue::FormIsSupported(form))
+        invalid_forms.insert(form);
+    }
+  }
+}
+
+//----------------------------------------------------------------------
 // Encode
 //
 // Encode the abbreviation table onto the end of the buffer provided
@@ -175,3 +190,12 @@ DWARFDebugAbbrev::GetAbbreviationDeclarationSet(
     return &(pos->second);
   return NULL;
 }
+
+//----------------------------------------------------------------------
+// DWARFDebugAbbrev::GetUnsupportedForms()
+//----------------------------------------------------------------------
+void DWARFDebugAbbrev::GetUnsupportedForms(
+    std::set<dw_form_t> &invalid_forms) const {
+  for (const auto &pair : m_abbrevCollMap)
+    pair.second.GetUnsupportedForms(invalid_forms);
+}