[Lldb-commits] [PATCH] Let lldb dump line tables for DWARF v3

[Matthew Gardiner]

Hi people,

I have been looking into the support for ARM binary images by lldb. One 
of the ARM tool chains I use produces .debug_line tables as specified by 
DWARF v3. With lldb and llvm-dwarfdump built from the top of the tree, I 
observed that the dwarfdump tool dumps the line table, but lldb does 
not. After some investigation I discovered that the dump tool is built 
against llvm/lib/DebugInfo/DWARFDebugLine.cpp, whereas lldb uses 
lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugLine.cpp.

It turned out that the source used by lldb has a subtle difference in 
flow-control with regards the treatment of the line table's prologue 
version number compared to that of the llvm source. After duplication of 
this flow-control, it is possible for lldb to print the line-table built 
according to DWARF standards above and beyond v2.

Could somebody submit the following patch to the lldb tree which fixes 
this issue?

Index: source/Plugins/SymbolFile/DWARF/DWARFDebugLine.cpp
===================================================================
--- source/Plugins/SymbolFile/DWARF/DWARFDebugLine.cpp	(revision 205611)
+++ source/Plugins/SymbolFile/DWARF/DWARFDebugLine.cpp	(working copy)
@@ -418,7 +418,7 @@
      const char * s;
      prologue->total_length      = 
debug_line_data.GetDWARFInitialLength(offset_ptr);
      prologue->version           = debug_line_data.GetU16(offset_ptr);
-    if (prologue->version != 2)
+    if (prologue->version < 2)
        return false;

      prologue->prologue_length   = 
debug_line_data.GetDWARFOffset(offset_ptr);
@@ -486,7 +486,7 @@
      (void)debug_line_data.GetDWARFInitialLength(&offset);
      const char * s;
      uint32_t version = debug_line_data.GetU16(&offset);
-    if (version != 2)
+    if (version < 2)
        return false;

      const dw_offset_t end_prologue_offset = 
debug_line_data.GetDWARFOffset(&offset) + offset;


thank you
Matthew Gardiner


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