Author: gclayton
Date: Wed Jun 18 14:55:34 2014
New Revision: 211212
URL: http://llvm.org/viewvc/llvm-project?rev=211212&view=rev
Log:
Don't allow multiple line entries with the same address to exist sequentially.
The compiler, when JIT'ing code, can emit illegal DWARF line tables (address is
line table sequences must increase). This changes fixes that issue by replacing
previous line entries whose start address is the same with the new line entry
to avoid having multiple line entries with the same address. Since the address
range of lines entries is determined by the delta between the current and next
line entry, this shouldn't cause any issues.
Modified:
lldb/trunk/source/Symbol/LineTable.cpp
Modified: lldb/trunk/source/Symbol/LineTable.cpp
URL:
http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Symbol/LineTable.cpp?rev=211212&r1=211211&r2=211212&view=diff
==============================================================================
--- lldb/trunk/source/Symbol/LineTable.cpp (original)
+++ lldb/trunk/source/Symbol/LineTable.cpp Wed Jun 18 14:55:34 2014
@@ -96,7 +96,17 @@ LineTable::AppendLineEntryToSequence
assert(sequence != nullptr);
LineSequenceImpl* seq = reinterpret_cast<LineSequenceImpl*>(sequence);
Entry entry(file_addr, line, column, file_idx, is_start_of_statement,
is_start_of_basic_block, is_prologue_end, is_epilogue_begin, is_terminal_entry);
- seq->m_entries.push_back (entry);
+ entry_collection &entries = seq->m_entries;
+ // Replace the last entry if the address is the same, otherwise append it.
If we have multiple
+ // line entries at the same address, this indicates illegal DWARF so this
"fixes" the line table
+ // to be correct. If not fixed this can cause a line entry's address that
when resolved back to
+ // a symbol context, could resolve to a different line entry. We really
want a 1 to 1 mapping
+ // here to avoid these kinds of inconsistencies. We will need tor revisit
this if the DWARF line
+ // tables are updated to allow multiple entries at the same address
legally.
+ if (!entries.empty() && entries.back().file_addr == file_addr)
+ entries.back() = entry;
+ else
+ entries.push_back (entry);
}
void
_______________________________________________
lldb-commits mailing list
[email protected]
http://lists.cs.uiuc.edu/mailman/listinfo/lldb-commits
